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authorsss <sss@dark-alexandr.net>2023-01-17 00:38:19 +0300
committersss <sss@dark-alexandr.net>2023-01-17 00:38:19 +0300
commitcc3f33db7a8d3c4ad373e646b199808e01bc5d9b (patch)
treeec09d690c7656ab5f2cc72607e05fb359c24d8b2 /3rdparty/libev
added webrdp public code
Diffstat (limited to '3rdparty/libev')
-rw-r--r--3rdparty/libev/CMakeLists.txt63
-rw-r--r--3rdparty/libev/Changes617
-rw-r--r--3rdparty/libev/LICENSE37
-rw-r--r--3rdparty/libev/README59
-rw-r--r--3rdparty/libev/Symbols.ev73
-rw-r--r--3rdparty/libev/Symbols.event24
-rw-r--r--3rdparty/libev/TODO14
-rw-r--r--3rdparty/libev/cmake_config.h.in141
-rw-r--r--3rdparty/libev/ev++.h818
-rw-r--r--3rdparty/libev/ev.35819
-rw-r--r--3rdparty/libev/ev.c5627
-rw-r--r--3rdparty/libev/ev.h860
-rw-r--r--3rdparty/libev/ev.pod5741
-rw-r--r--3rdparty/libev/ev_epoll.c298
-rw-r--r--3rdparty/libev/ev_iouring.c694
-rw-r--r--3rdparty/libev/ev_kqueue.c224
-rw-r--r--3rdparty/libev/ev_linuxaio.c620
-rw-r--r--3rdparty/libev/ev_poll.c156
-rw-r--r--3rdparty/libev/ev_port.c192
-rw-r--r--3rdparty/libev/ev_select.c316
-rw-r--r--3rdparty/libev/ev_vars.h249
-rw-r--r--3rdparty/libev/ev_win32.c162
-rw-r--r--3rdparty/libev/ev_wrap.h272
-rw-r--r--3rdparty/libev/event.c425
-rw-r--r--3rdparty/libev/event.h177
25 files changed, 23678 insertions, 0 deletions
diff --git a/3rdparty/libev/CMakeLists.txt b/3rdparty/libev/CMakeLists.txt
new file mode 100644
index 0000000..1284d51
--- /dev/null
+++ b/3rdparty/libev/CMakeLists.txt
@@ -0,0 +1,63 @@
+cmake_minimum_required(VERSION 3.0 FATAL_ERROR)
+
+project(libev C)
+
+set (libev_VERSION_MAJOR 4)
+set (libev_VERSION_MINOR 33)
+set(VERSION TRUE)
+
+include_directories("${PROJECT_SOURCE_DIR}")
+include_directories("${PROJECT_BINARY_DIR}")
+
+include(CheckSymbolExists)
+
+set(LIBEV_SOURCES ev.c event.c)
+
+check_symbol_exists(epoll_ctl sys/epoll.h HAVE_EPOLL_CTL)
+check_symbol_exists(clock_gettime time.h HAVE_CLOCK_GETTIME)
+find_file(HAVE_DLFCN_H dlfcn.h)
+check_symbol_exists(eventfd sys/eventfd.h HAVE_EVENTFD)
+set(CMAKE_REQUIRED_LIBRARIES -lm)
+check_symbol_exists(floor math.h HAVE_FLOOR)
+check_symbol_exists(inotify_init sys/inotify.h HAVE_INOTIFY_INIT)
+find_file(HAVE_INTTYPES_H inttypes.h)
+check_symbol_exists(kqueue sys/time.h;sys/types.h;sys/event.h HAVE_KQUEUE)
+find_library(HAVE_LIBRT librt.so)
+find_file(HAVE_MEMORY_H memory.h)
+check_symbol_exists(nanosleep time.h HAVE_NANOSLEEP)
+check_symbol_exists(poll poll.h HAVE_POLL)
+find_file(HAVE_POLL_H poll.h)
+check_symbol_exists(port_create port.h HAVE_PORT_CREATE)
+find_file(HAVE_PORT_H port.h)
+check_symbol_exists(select sys/select.h HAVE_SELECT)
+check_symbol_exists(signalfd sys/signalfd.h HAVE_SIGNALFD)
+find_file(HAVE_STDINT_H stdint.h)
+find_file(HAVE_STDLIB_H stdlib.h)
+find_file(HAVE_STRINGS_H strings.h)
+find_file(HAVE_STRING_H string.h)
+find_file(HAVE_SYS_EPOLL_H sys/epoll.h)
+find_file(HAVE_SYS_EVENTFD_H sys/eventfd.h)
+find_file(HAVE_SYS_EVENT_H sys/event.h)
+find_file(HAVE_SYS_INOTIFY_H sys/inotify.h)
+find_file(HAVE_SYS_SELECT_H sys/select.h)
+find_file(HAVE_SYS_SIGNALFD_H sys/signalfd.h)
+find_file(HAVE_SYS_STAT_H sys/stat.h)
+find_file(HAVE_SYS_TYPES_H sys/types.h)
+find_file(HAVE_UNISTD_H unistd.h)
+find_file(HAVE_LINUX_AIO_ABI_H linux/aio_abi.h)
+check_symbol_exists(kernel_rwf_t linux/fs.h HAVE_KERNEL_RWF_T)
+find_file(HAVE_LINUX_FS_H linux/fs.h)
+find_file(HAVE_SYS_TIMERFD_H sys/timerfd.h)
+
+
+configure_file (
+ "${PROJECT_SOURCE_DIR}/cmake_config.h.in"
+ "${PROJECT_BINARY_DIR}/config.h"
+)
+
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DHAVE_CONFIG_H -fPIC -DPIC")
+
+add_library(ev STATIC ${LIBEV_SOURCES})
+
+
+
diff --git a/3rdparty/libev/Changes b/3rdparty/libev/Changes
new file mode 100644
index 0000000..d200b9e
--- /dev/null
+++ b/3rdparty/libev/Changes
@@ -0,0 +1,617 @@
+Revision history for libev, a high-performance and full-featured event loop.
+
+TODO: for next ABI/API change, consider moving EV__IOFDSSET into io->fd instead and provide a getter.
+TODO: document EV_TSTAMP_T
+
+4.33 Wed Mar 18 13:22:29 CET 2020
+ - no changes w.r.t. 4.32.
+
+4.32 (EV only)
+ - the 4.31 timerfd code wrongly changed the priority of the signal
+ fd watcher, which is usually harmless unless signal fds are
+ also used (found via cpan tester service).
+ - the documentation wrongly claimed that user may modify fd and events
+ members in io watchers when the watcher was stopped
+ (found by b_jonas).
+ - new ev_io_modify mutator which changes only the events member,
+ which can be faster. also added ev::io::set (int events) method
+ to ev++.h.
+ - officially allow a zero events mask for io watchers. this should
+ work with older libev versions as well but was not officially
+ allowed before.
+ - do not wake up every minute when timerfd is used to detect timejumps.
+ - do not wake up every minute when periodics are disabled and we have
+ a monotonic clock.
+ - support a lot more "uncommon" compile time configurations,
+ such as ev_embed enabled but ev_timer disabled.
+ - use a start/stop wrapper class to reduce code duplication in
+ ev++.h and make it needlessly more c++-y.
+ - the linux aio backend is no longer compiled in by default.
+ - update to libecb version 0x00010008.
+
+4.31 Fri Dec 20 21:58:29 CET 2019
+ - handle backends with minimum wait time a bit better by not
+ waiting in the presence of already-expired timers
+ (behaviour reported by Felipe Gasper).
+ - new feature: use timerfd to detect timejumps quickly,
+ can be disabled with the new EVFLAG_NOTIMERFD loop flag.
+ - document EV_USE_SIGNALFD feature macro.
+
+4.30 (EV only)
+ - change non-autoconf test for __kernel_rwf_t by testing
+ LINUX_VERSION_CODE, the most direct test I could find.
+ - fix a bug in the io_uring backend that polled the wrong
+ backend fd, causing it to not work in many cases.
+
+4.29 (EV only)
+ - add io uring autoconf and non-autoconf detection.
+ - disable io_uring when some header files are too old.
+
+4.28 (EV only)
+ - linuxaio backend resulted in random memory corruption
+ when loop is forked.
+ - linuxaio backend might have tried to cancel an iocb
+ multiple times (was unable to trigger this).
+ - linuxaio backend now employs a generation counter to
+ avoid handling spurious events from cancelled requests.
+ - io_cancel can return EINTR, deal with it. also, assume
+ io_submit also returns EINTR.
+ - fix some other minor bugs in linuxaio backend.
+ - ev_tstamp type can now be overriden by defining EV_TSTAMP_T.
+ - cleanup: replace expect_true/false and noinline by their
+ libecb counterparts.
+ - move syscall infrastructure from ev_linuxaio.c to ev.c.
+ - prepare io_uring integration.
+ - tweak ev_floor.
+ - epoll, poll, win32 Sleep and other places that use millisecond
+ reslution now all try to round up times.
+ - solaris port backend didn't compile.
+ - abstract time constants into their macros, for more flexibility.
+
+4.27 Thu Jun 27 22:43:44 CEST 2019
+ - linux aio backend almost completely rewritten to work around its
+ limitations.
+ - linux aio backend now requires linux 4.19+.
+ - epoll backend now mandatory for linux aio backend.
+ - fail assertions more aggressively on invalid fd's detected
+ in the event loop, do not just silently fd_kill in case of
+ user error.
+ - ev_io_start/ev_io_stop now verify the watcher fd using
+ a syscall when EV_VERIFY is 2 or higher.
+
+4.26 (EV only)
+ - update to libecb 0x00010006.
+ - new experimental linux aio backend (linux 4.18+).
+ - removed redundant 0-ptr check in ev_once.
+ - updated/extended ev_set_allocator documentation.
+ - replaced EMPTY2 macro by array_needsize_noinit.
+ - minor code cleanups.
+ - epoll backend now uses epoll_create1 also after fork.
+
+4.25 Fri Dec 21 07:49:20 CET 2018
+ - INCOMPATIBLE CHANGE: EV_THROW was renamed to EV_NOEXCEPT
+ (EV_THROW still provided) and now uses noexcept on C++11 or newer.
+ - move the darwin select workaround higher in ev.c, as newer versions of
+ darwin managed to break their broken select even more.
+ - ANDROID => __ANDROID__ (reported by enh@google.com).
+ - disable epoll_create1 on android because it has broken header files
+ and google is unwilling to fix them (reported by enh@google.com).
+ - avoid a minor compilation warning on win32.
+ - c++: remove deprecated dynamic throw() specifications.
+ - c++: improve the (unsupported) bad_loop exception class.
+ - backport perl ev_periodic example to C, untested.
+ - update libecb, biggets change is to include a memory fence
+ in ECB_MEMORY_FENCE_RELEASE on x86/amd64.
+ - minor autoconf/automake modernisation.
+
+4.24 Wed Dec 28 05:19:55 CET 2016
+ - bump version to 4.24, as the release tarball inexplicably
+ didn't have the right version in ev.h, even though the cvs-tagged
+ version did have the right one (reported by Ales Teska).
+
+4.23 Wed Nov 16 18:23:41 CET 2016
+ - move some declarations at the beginning to help certain retarded
+ microsoft compilers, even though their documentation claims
+ otherwise (reported by Ruslan Osmanov).
+
+4.22 Sun Dec 20 22:11:50 CET 2015
+ - when epoll detects unremovable fds in the fd set, rebuild
+ only the epoll descriptor, not the signal pipe, to avoid
+ SIGPIPE in ev_async_send. This doesn't solve it on fork,
+ so document what needs to be done in ev_loop_fork
+ (analyzed by Benjamin Mahler).
+ - remove superfluous sys/timeb.h include on win32
+ (analyzed by Jason Madden).
+ - updated libecb.
+
+4.20 Sat Jun 20 13:01:43 CEST 2015
+ - prefer noexcept over throw () with C++ 11.
+ - update ecb.h due to incompatibilities with c11.
+ - fix a potential aliasing issue when reading and writing
+ watcher callbacks.
+
+4.19 Thu Sep 25 08:18:25 CEST 2014
+ - ev.h wasn't valid C++ anymore, which tripped compilers other than
+ clang, msvc or gcc (analyzed by Raphael 'kena' Poss). Unfortunately,
+ C++ doesn't support typedefs for function pointers fully, so the affected
+ declarations have to spell out the types each time.
+ - when not using autoconf, tighten the check for clock_gettime and related
+ functionality.
+
+4.18 Fri Sep 5 17:55:26 CEST 2014
+ - events on files were not always generated properly with the
+ epoll backend (testcase by Assaf Inbal).
+ - mark event pipe fd as cloexec after a fork (analyzed by Sami Farin).
+ - (ecb) support m68k, m88k and sh (patch by Miod Vallat).
+ - use a reasonable fallback for EV_NSIG instead of erroring out
+ when we can't detect the signal set size.
+ - in the absence of autoconf, do not use the clock syscall
+ on glibc >= 2.17 (avoids the syscall AND -lrt on systems
+ doing clock_gettime in userspace).
+ - ensure extern "C" function pointers are used for externally-visible
+ loop callbacks (not watcher callbacks yet).
+ - (ecb) work around memory barriers and volatile apparently both being
+ broken in visual studio 2008 and later (analysed and patch by Nicolas Noble).
+
+4.15 Fri Mar 1 12:04:50 CET 2013
+ - destroying a non-default loop would stop the global waitpid
+ watcher (Denis Bilenko).
+ - queueing pending watchers of higher priority from a watcher now invokes
+ them in a timely fashion (reported by Denis Bilenko).
+ - add throw() to all libev functions that cannot throw exceptions, for
+ further code size decrease when compiling for C++.
+ - add throw () to callbacks that must not throw exceptions (allocator,
+ syserr, loop acquire/release, periodic reschedule cbs).
+ - fix event_base_loop return code, add event_get_callback, event_base_new,
+ event_base_get_method calls to improve libevent 1.x emulation and add
+ some libevent 2.x functionality (based on a patch by Jeff Davey).
+ - add more memory fences to fix a bug reported by Jeff Davey. Better
+ be overfenced than underprotected.
+ - ev_run now returns a boolean status (true meaning watchers are
+ still active).
+ - ev_once: undef EV_ERROR in ev_kqueue.c, to avoid clashing with
+ libev's EV_ERROR (reported by 191919).
+ - (ecb) add memory fence support for xlC (Darin McBride).
+ - (ecb) add memory fence support for gcc-mips (Anton Kirilov).
+ - (ecb) add memory fence support for gcc-alpha (Christian Weisgerber).
+ - work around some kernels losing file descriptors by leaking
+ the kqueue descriptor in the child.
+ - work around linux inotify not reporting IN_ATTRIB changes for directories
+ in many cases.
+ - include sys/syscall.h instead of plain syscall.h.
+ - check for io watcher loops in ev_verify, check for the most
+ common reported usage bug in ev_io_start.
+ - choose socket vs. WSASocket at compiletime using EV_USE_WSASOCKET.
+ - always use WSASend/WSARecv directly on windows, hoping that this
+ works in all cases (unlike read/write/send/recv...).
+ - try to detect signals around a fork faster (test program by
+ Denis Bilenko).
+ - work around recent glibc versions that leak memory in realloc.
+ - rename ev::embed::set to ev::embed::set_embed to avoid clashing
+ the watcher base set (loop) method.
+ - rewrite the async/signal pipe logic to always keep a valid fd, which
+ simplifies (and hopefully correctifies :) the race checking
+ on fork, at the cost of one extra fd.
+ - add fat, msdos, jffs2, ramfs, ntfs and btrfs to the list of
+ inotify-supporting filesystems.
+ - move orig_CFLAGS assignment to after AC_INIT, as newer autoconf
+ versions ignore it before
+ (https://bugzilla.redhat.com/show_bug.cgi?id=908096).
+ - add some untested android support.
+ - enum expressions must be of type int (reported by Juan Pablo L).
+
+4.11 Sat Feb 4 19:52:39 CET 2012
+ - INCOMPATIBLE CHANGE: ev_timer_again now clears the pending status, as
+ was documented already, but not implemented in the repeating case.
+ - new compiletime symbols: EV_NO_SMP and EV_NO_THREADS.
+ - fix a race where the workaround against the epoll fork bugs
+ caused signals to not be handled anymore.
+ - correct backend_fudge for most backends, and implement a windows
+ specific workaround to avoid looping because we call both
+ select and Sleep, both with different time resolutions.
+ - document range and guarantees of ev_sleep.
+ - document reasonable ranges for periodics interval and offset.
+ - rename backend_fudge to backend_mintime to avoid future confusion :)
+ - change the default periodic reschedule function to hopefully be more
+ exact and correct even in corner cases or in the far future.
+ - do not rely on -lm anymore: use it when available but use our
+ own floor () if it is missing. This should make it easier to embed,
+ as no external libraries are required.
+ - strategically import macros from libecb and mark rarely-used functions
+ as cache-cold (saving almost 2k code size on typical amd64 setups).
+ - add Symbols.ev and Symbols.event files, that were missing.
+ - fix backend_mintime value for epoll (was 1/1024, is 1/1000 now).
+ - fix #3 "be smart about timeouts" to not "deadlock" when
+ timeout == now, also improve the section overall.
+ - avoid "AVOIDING FINISHING BEFORE RETURNING" idiom.
+ - support new EV_API_STATIC mode to make all libev symbols
+ static.
+ - supply default CFLAGS of -g -O3 with gcc when original CFLAGS
+ were empty.
+
+4.04 Wed Feb 16 09:01:51 CET 2011
+ - fix two problems in the native win32 backend, where reuse of fd's
+ with different underlying handles caused handles not to be removed
+ or added to the select set (analyzed and tested by Bert Belder).
+ - do no rely on ceil() in ev_e?poll.c.
+ - backport libev to HP-UX versions before 11 v3.
+ - configure did not detect nanosleep and clock_gettime properly when
+ they are available in the libc (as opposed to -lrt).
+
+4.03 Tue Jan 11 14:37:25 CET 2011
+ - officially support polling files with all backends.
+ - support files, /dev/zero etc. the same way as select in the epoll
+ backend, by generating events on our own.
+ - ports backend: work around solaris bug 6874410 and many related ones
+ (EINTR, maybe more), with no performance loss (note that the solaris
+ bug report is actually wrong, reality is far more bizarre and broken
+ than that).
+ - define EV_READ/EV_WRITE as macros in event.h, as some programs use
+ #ifdef to test for them.
+ - new (experimental) function: ev_feed_signal.
+ - new (to become default) EVFLAG_NOSIGMASK flag.
+ - new EVBACKEND_MASK symbol.
+ - updated COMMON IDIOMS SECTION.
+
+4.01 Fri Nov 5 21:51:29 CET 2010
+ - automake fucked it up, apparently, --add-missing -f is not quite enough
+ to make it update its files, so 4.00 didn't install ev++.h and
+ event.h on make install. grrr.
+ - ev_loop(count|depth) didn't return anything (Robin Haberkorn).
+ - change EV_UNDEF to 0xffffffff to silence some overzealous compilers.
+ - use "(libev) " prefix for all libev error messages now.
+
+4.00 Mon Oct 25 12:32:12 CEST 2010
+ - "PORTING FROM LIBEV 3.X TO 4.X" (in ev.pod) is recommended reading.
+ - ev_embed_stop did not correctly stop the watcher (very good
+ testcase by Vladimir Timofeev).
+ - ev_run will now always update the current loop time - it erroneously
+ didn't when idle watchers were active, causing timers not to fire.
+ - fix a bug where a timeout of zero caused the timer not to fire
+ in the libevent emulation (testcase by Péter Szabó).
+ - applied win32 fixes by Michael Lenaghan (also James Mansion).
+ - replace EV_MINIMAL by EV_FEATURES.
+ - prefer EPOLL_CTL_ADD over EPOLL_CTL_MOD in some more cases, as it
+ seems the former is *much* faster than the latter.
+ - linux kernel version detection (for inotify bug workarounds)
+ did not work properly.
+ - reduce the number of spurious wake-ups with the ports backend.
+ - remove dependency on sys/queue.h on freebsd (patch by Vanilla Hsu).
+ - do async init within ev_async_start, not ev_async_set, which avoids
+ an API quirk where the set function must be called in the C++ API
+ even when there is nothing to set.
+ - add (undocumented) EV_ENABLE when adding events with kqueue,
+ this might help with OS X, which seems to need it despite documenting
+ not to need it (helpfully pointed out by Tilghman Lesher).
+ - do not use poll by default on freebsd, it's broken (what isn't
+ on freebsd...).
+ - allow to embed epoll on kernels >= 2.6.32.
+ - configure now prepends -O3, not appends it, so one can still
+ override it.
+ - ev.pod: greatly expanded the portability section, added a porting
+ section, a description of watcher states and made lots of minor fixes.
+ - disable poll backend on AIX, the poll header spams the namespace
+ and it's not worth working around dead platforms (reported
+ and analyzed by Aivars Kalvans).
+ - improve header file compatibility of the standalone eventfd code
+ in an obscure case.
+ - implement EV_AVOID_STDIO option.
+ - do not use sscanf to parse linux version number (smaller, faster,
+ no sscanf dependency).
+ - new EV_CHILD_ENABLE and EV_SIGNAL_ENABLE configurable settings.
+ - update libev.m4 HAVE_CLOCK_SYSCALL test for newer glibcs.
+ - add section on accept() problems to the manpage.
+ - rename EV_TIMEOUT to EV_TIMER.
+ - rename ev_loop_count/depth/verify/loop/unloop.
+ - remove ev_default_destroy and ev_default_fork.
+ - switch to two-digit minor version.
+ - work around an apparent gentoo compiler bug.
+ - define _DARWIN_UNLIMITED_SELECT. just so.
+ - use enum instead of #define for most constants.
+ - improve compatibility to older C++ compilers.
+ - (experimental) ev_run/ev_default_loop/ev_break/ev_loop_new have now
+ default arguments when compiled as C++.
+ - enable automake dependency tracking.
+ - ev_loop_new no longer leaks memory when loop creation failed.
+ - new ev_cleanup watcher type.
+
+3.9 Thu Dec 31 07:59:59 CET 2009
+ - signalfd is no longer used by default and has to be requested
+ explicitly - this means that easy to catch bugs become hard to
+ catch race conditions, but the users have spoken.
+ - point out the unspecified signal mask in the documentation, and
+ that this is a race condition regardless of EV_SIGNALFD.
+ - backport inotify code to C89.
+ - inotify file descriptors could leak into child processes.
+ - ev_stat watchers could keep an erroneous extra ref on the loop,
+ preventing exit when unregistering all watchers (testcases
+ provided by ry@tinyclouds.org).
+ - implement EV_WIN32_HANDLE_TO_FD and EV_WIN32_CLOSE_FD configuration
+ symbols to make it easier for apps to do their own fd management.
+ - support EV_IDLE_ENABLE being disabled in ev++.h
+ (patch by Didier Spezia).
+ - take advantage of inotify_init1, if available, to set cloexec/nonblock
+ on fd creation, to avoid races.
+ - the signal handling pipe wasn't always initialised under windows
+ (analysed by lekma).
+ - changed minimum glibc requirement from glibc 2.9 to 2.7, for
+ signalfd.
+ - add missing string.h include (Denis F. Latypoff).
+ - only replace ev_stat.prev when we detect an actual difference,
+ so prev is (almost) always different to attr. this might
+ have caused the problems with 04_stat.t.
+ - add ev::timer->remaining () method to C++ API.
+
+3.8 Sun Aug 9 14:30:45 CEST 2009
+ - incompatible change: do not necessarily reset signal handler
+ to SIG_DFL when a sighandler is stopped.
+ - ev_default_destroy did not properly free or zero some members,
+ potentially causing crashes and memory corruption on repeated
+ ev_default_destroy/ev_default_loop calls.
+ - take advantage of signalfd on GNU/Linux systems.
+ - document that the signal mask might be in an unspecified
+ state when using libev's signal handling.
+ - take advantage of some GNU/Linux calls to set cloexec/nonblock
+ on fd creation, to avoid race conditions.
+
+3.7 Fri Jul 17 16:36:32 CEST 2009
+ - ev_unloop and ev_loop wrongly used a global variable to exit loops,
+ instead of using a per-loop variable (bug caught by accident...).
+ - the ev_set_io_collect_interval interpretation has changed.
+ - add new functionality: ev_set_userdata, ev_userdata,
+ ev_set_invoke_pending_cb, ev_set_loop_release_cb,
+ ev_invoke_pending, ev_pending_count, together with a long example
+ about thread locking.
+ - add ev_timer_remaining (as requested by Denis F. Latypoff).
+ - add ev_loop_depth.
+ - calling ev_unloop in fork/prepare watchers will no longer poll
+ for new events.
+ - Denis F. Latypoff corrected many typos in example code snippets.
+ - honor autoconf detection of EV_USE_CLOCK_SYSCALL, also double-
+ check that the syscall number is available before trying to
+ use it (reported by ry@tinyclouds).
+ - use GetSystemTimeAsFileTime instead of _timeb on windows, for
+ slightly higher accuracy.
+ - properly declare ev_loop_verify and ev_now_update even when
+ !EV_MULTIPLICITY.
+ - do not compile in any priority code when EV_MAXPRI == EV_MINPRI.
+ - support EV_MINIMAL==2 for a reduced API.
+ - actually 0-initialise struct sigaction when installing signals.
+ - add section on hibernate and stopped processes to ev_timer docs.
+
+3.6 Tue Apr 28 02:49:30 CEST 2009
+ - multiple timers becoming ready within an event loop iteration
+ will be invoked in the "correct" order now.
+ - do not leave the event loop early just because we have no active
+ watchers, fixing a problem when embedding a kqueue loop
+ that has active kernel events but no registered watchers
+ (reported by blacksand blacksand).
+ - correctly zero the idx values for arrays, so destroying and
+ reinitialising the default loop actually works (patch by
+ Malek Hadj-Ali).
+ - implement ev_suspend and ev_resume.
+ - new EV_CUSTOM revents flag for use by applications.
+ - add documentation section about priorities.
+ - add a glossary to the documentation.
+ - extend the ev_fork description slightly.
+ - optimize a jump out of call_pending.
+
+3.53 Sun Feb 15 02:38:20 CET 2009
+ - fix a bug in event pipe creation on win32 that would cause a
+ failed assertion on event loop creation (patch by Malek Hadj-Ali).
+ - probe for CLOCK_REALTIME support at runtime as well and fall
+ back to gettimeofday if there is an error, to support older
+ operating systems with newer header files/libraries.
+ - prefer gettimeofday over clock_gettime with USE_CLOCK_SYSCALL
+ (default most everywhere), otherwise not.
+
+3.52 Wed Jan 7 21:43:02 CET 2009
+ - fix compilation of select backend in fd_set mode when NFDBITS is
+ missing (to get it to compile on QNX, reported by Rodrigo Campos).
+ - better select-nfds handling when select backend is in fd_set mode.
+ - diagnose fd_set overruns when select backend is in fd_set mode.
+ - due to a thinko, instead of disabling everything but
+ select on the borked OS X platform, everything but select was
+ allowed (reported by Emanuele Giaquinta).
+ - actually verify that local and remote port are matching in
+ libev's socketpair emulation, which makes denial-of-service
+ attacks harder (but not impossible - it's windows). Make sure
+ it even works under vista, which thinks that getpeer/sockname
+ should return fantasy port numbers.
+ - include "libev" in all assertion messages for potentially
+ clearer diagnostics.
+ - event_get_version (libevent compatibility) returned
+ a useless string instead of the expected version string
+ (patch by W.C.A. Wijngaards).
+
+3.51 Wed Dec 24 23:00:11 CET 2008
+ - fix a bug where an inotify watcher was added twice, causing
+ freezes on hash collisions (reported and analysed by Graham Leggett).
+ - new config symbol, EV_USE_CLOCK_SYSCALL, to make libev use
+ a direct syscall - slower, but no dependency on librt et al.
+ - assume negative return values != -1 signals success of port_getn
+ (http://cvs.epicsol.org/cgi/viewcvs.cgi/epic5/source/newio.c?rev=1.52)
+ (no known failure reports, but it doesn't hurt).
+ - fork detection in ev_embed now stops and restarts the watcher
+ automatically.
+ - EXPERIMENTAL: default the method to operator () in ev++.h,
+ to make it nicer to use functors (requested by Benedek László).
+ - fixed const object callbacks in ev++.h.
+ - replaced loop_ref argument of watcher.set (loop) by a direct
+ ev_loop * in ev++.h, to avoid clashes with functor patch.
+ - do not try to watch the empty string via inotify.
+ - inotify watchers could be leaked under certain circumstances.
+ - OS X 10.5 is actually even more broken than earlier versions,
+ so fall back to select on that piece of garbage.
+ - fixed some weirdness in the ev_embed documentation.
+
+3.49 Wed Nov 19 11:26:53 CET 2008
+ - ev_stat watchers will now use inotify as a mere hint on
+ kernels <2.6.25, or if the filesystem is not in the
+ "known to be good" list.
+ - better mingw32 compatibility (it's not as borked as native win32)
+ (analysed by Roger Pack).
+ - include stdio.h in the example program, as too many people are
+ confused by the weird C language otherwise. I guess the next thing
+ I get told is that the "..." ellipses in the examples don't compile
+ with their C compiler.
+
+3.48 Thu Oct 30 09:02:37 CET 2008
+ - further optimise away the EPOLL_CTL_ADD/MOD combo in the epoll
+ backend by assuming the kernel event mask hasn't changed if
+ ADD fails with EEXIST.
+ - work around spurious event notification bugs in epoll by using
+ a 32-bit generation counter. recreate kernel state if we receive
+ spurious notifications or unwanted events. this is very costly,
+ but I didn't come up with this horrible design.
+ - use memset to initialise most arrays now and do away with the
+ init functions.
+ - expand time-out strategies into a "Be smart about timeouts" section.
+ - drop the "struct" from all ev_watcher declarations in the
+ documentation and did other clarifications (yeah, it was a mistake
+ to have a struct AND a function called ev_loop).
+ - fix a bug where ev_default would not initialise the default
+ loop again after it was destroyed with ev_default_destroy.
+ - rename syserr to ev_syserr to avoid name clashes when embedding,
+ do similar changes for event.c.
+
+3.45 Tue Oct 21 21:59:26 CEST 2008
+ - disable inotify usage on linux <2.6.25, as it is broken
+ (reported by Yoann Vandoorselaere).
+ - ev_stat erroneously would try to add inotify watchers
+ even when inotify wasn't available (this should only
+ have a performance impact).
+ - ev_once now passes both timeout and io to the callback if both
+ occur concurrently, instead of giving timeouts precedence.
+ - disable EV_USE_INOTIFY when sys/inotify.h is too old.
+
+3.44 Mon Sep 29 05:18:39 CEST 2008
+ - embed watchers now automatically invoke ev_loop_fork on the
+ embedded loop when the parent loop forks.
+ - new function: ev_now_update (loop).
+ - verify_watcher was not marked static.
+ - improve the "associating..." manpage section.
+ - documentation tweaks here and there.
+
+3.43 Sun Jul 6 05:34:41 CEST 2008
+ - include more include files on windows to get struct _stati64
+ (reported by Chris Hulbert, but doesn't quite fix his issue).
+ - add missing #include <io.h> in ev.c on windows (reported by
+ Matt Tolton).
+
+3.42 Tue Jun 17 12:12:07 CEST 2008
+ - work around yet another windows bug: FD_SET actually adds fd's
+ multiple times to the fd_*SET*, despite official MSN docs claiming
+ otherwise. Reported and well-analysed by Matt Tolton.
+ - define NFDBITS to 0 when EV_SELECT_IS_WINSOCKET to make it compile
+ (reported any analysed by Chris Hulbert).
+ - fix a bug in ev_ebadf (this function is only used to catch
+ programming errors in the libev user). reported by Matt Tolton.
+ - fix a bug in fd_intern on win32 (could lead to compile errors
+ under some circumstances, but would work correctly if it compiles).
+ reported by Matt Tolton.
+ - (try to) work around missing lstat on windows.
+ - pass in the write fd set as except fd set under windows. windows
+ is so uncontrollably lame that it requires this. this means that
+ switching off oobinline is not supported (but tcp/ip doesn't
+ have oob, so that would be stupid anyways.
+ - use posix module symbol to auto-detect monotonic clock presence
+ and some other default values.
+
+3.41 Fri May 23 18:42:54 CEST 2008
+ - work around an obscure bug in winsocket select: if you
+ provide only empty fd sets then select returns WSAEINVAL. how sucky.
+ - improve timer scheduling stability and reduce use of time_epsilon.
+ - use 1-based 2-heap for EV_MINIMAL, simplifies code, reduces
+ codesize and makes for better cache-efficiency.
+ - use 3-based 4-heap for !EV_MINIMAL. this makes better use
+ of cpu cache lines and gives better growth behaviour than
+ 2-based heaps.
+ - cache timestamp within heap for !EV_MINIMAL, to avoid random
+ memory accesses.
+ - document/add EV_USE_4HEAP and EV_HEAP_CACHE_AT.
+ - fix a potential aliasing issue in ev_timer_again.
+ - add/document ev_periodic_at, retract direct access to ->at.
+ - improve ev_stat docs.
+ - add portability requirements section.
+ - fix manpage headers etc.
+ - normalise WSA error codes to lower range on windows.
+ - add consistency check code that can be called automatically
+ or on demand to check for internal structures (ev_loop_verify).
+
+3.31 Wed Apr 16 20:45:04 CEST 2008
+ - added last minute fix for ev_poll.c by Brandon Black.
+
+3.3 Wed Apr 16 19:04:10 CEST 2008
+ - event_base_loopexit should return 0 on success
+ (W.C.A. Wijngaards).
+ - added linux eventfd support.
+ - try to autodetect epoll and inotify support
+ by libc header version if not using autoconf.
+ - new symbols: EV_DEFAULT_UC and EV_DEFAULT_UC_.
+ - declare functions defined in ev.h as inline if
+ C99 or gcc are available.
+ - enable inlining with gcc versions 2 and 3.
+ - work around broken poll implementations potentially
+ not clearing revents field in ev_poll (Brandon Black)
+ (no such systems are known at this time).
+ - work around a bug in realloc on openbsd and darwin,
+ also makes the erroneous valgrind complaints
+ go away (noted by various people).
+ - fix ev_async_pending, add c++ wrapper for ev_async
+ (based on patch sent by Johannes Deisenhofer).
+ - add sensible set method to ev::embed.
+ - made integer constants type int in ev.h.
+
+3.2 Wed Apr 2 17:11:19 CEST 2008
+ - fix a 64 bit overflow issue in the select backend,
+ by using fd_mask instead of int for the mask.
+ - rename internal sighandler to avoid clash with very old perls.
+ - entering ev_loop will not clear the ONESHOT or NONBLOCKING
+ flags of any outer loops anymore.
+ - add ev_async_pending.
+
+3.1 Thu Mar 13 13:45:22 CET 2008
+ - implement ev_async watchers.
+ - only initialise signal pipe on demand.
+ - make use of sig_atomic_t configurable.
+ - improved documentation.
+
+3.0 Mon Jan 28 13:14:47 CET 2008
+ - API/ABI bump to version 3.0.
+ - ev++.h includes "ev.h" by default now, not <ev.h>.
+ - slightly improved documentation.
+ - speed up signal detection after a fork.
+ - only optionally return trace status changed in ev_child
+ watchers.
+ - experimental (and undocumented) loop wrappers for ev++.h.
+
+2.01 Tue Dec 25 08:04:41 CET 2007
+ - separate Changes file.
+ - fix ev_path_set => ev_stat_set typo.
+ - remove event_compat.h from the libev tarball.
+ - change how include files are found.
+ - doc updates.
+ - update licenses, explicitly allow for GPL relicensing.
+
+2.0 Sat Dec 22 17:47:03 CET 2007
+ - new ev_sleep, ev_set_(io|timeout)_collect_interval.
+ - removed epoll from embeddable fd set.
+ - fix embed watchers.
+ - renamed ev_embed.loop to other.
+ - added exported Symbol tables.
+ - undefine member wrapper macros at the end of ev.c.
+ - respect EV_H in ev++.h.
+
+1.86 Tue Dec 18 02:36:57 CET 2007
+ - fix memleak on loop destroy (not relevant for perl).
+
+1.85 Fri Dec 14 20:32:40 CET 2007
+ - fix some aliasing issues w.r.t. timers and periodics
+ (not relevant for perl).
+
+(for historic versions refer to EV/Changes, found in the Perl interface)
+
+0.1 Wed Oct 31 21:31:48 CET 2007
+ - original version; hacked together in <24h.
+
diff --git a/3rdparty/libev/LICENSE b/3rdparty/libev/LICENSE
new file mode 100644
index 0000000..2fdabd4
--- /dev/null
+++ b/3rdparty/libev/LICENSE
@@ -0,0 +1,37 @@
+All files in libev are
+Copyright (c)2007,2008,2009,2010,2011,2012,2013 Marc Alexander Lehmann.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above
+ copyright notice, this list of conditions and the following
+ disclaimer in the documentation and/or other materials provided
+ with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+Alternatively, the contents of this package may be used under the terms
+of the GNU General Public License ("GPL") version 2 or any later version,
+in which case the provisions of the GPL are applicable instead of the
+above. If you wish to allow the use of your version of this package only
+under the terms of the GPL and not to allow others to use your version of
+this file under the BSD license, indicate your decision by deleting the
+provisions above and replace them with the notice and other provisions
+required by the GPL in this and the other files of this package. If you do
+not delete the provisions above, a recipient may use your version of this
+file under either the BSD or the GPL.
diff --git a/3rdparty/libev/README b/3rdparty/libev/README
new file mode 100644
index 0000000..fca5fdf
--- /dev/null
+++ b/3rdparty/libev/README
@@ -0,0 +1,59 @@
+libev is a high-performance event loop/event model with lots of features.
+(see benchmark at http://libev.schmorp.de/bench.html)
+
+
+ABOUT
+
+ Homepage: http://software.schmorp.de/pkg/libev
+ Mailinglist: libev@lists.schmorp.de
+ http://lists.schmorp.de/cgi-bin/mailman/listinfo/libev
+ Library Documentation: http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod
+
+ Libev is modelled (very losely) after libevent and the Event perl
+ module, but is faster, scales better and is more correct, and also more
+ featureful. And also smaller. Yay.
+
+ Some of the specialties of libev not commonly found elsewhere are:
+
+ - extensive and detailed, readable documentation (not doxygen garbage).
+ - fully supports fork, can detect fork in various ways and automatically
+ re-arms kernel mechanisms that do not support fork.
+ - highly optimised select, poll, linux epoll, linux aio, bsd kqueue
+ and solaris event ports backends.
+ - filesystem object (path) watching (with optional linux inotify support).
+ - wallclock-based times (using absolute time, cron-like).
+ - relative timers/timeouts (handle time jumps).
+ - fast intra-thread communication between multiple
+ event loops (with optional fast linux eventfd backend).
+ - extremely easy to embed (fully documented, no dependencies,
+ autoconf supported but optional).
+ - very small codebase, no bloated library, simple code.
+ - fully extensible by being able to plug into the event loop,
+ integrate other event loops, integrate other event loop users.
+ - very little memory use (small watchers, small event loop data).
+ - optional C++ interface allowing method and function callbacks
+ at no extra memory or runtime overhead.
+ - optional Perl interface with similar characteristics (capable
+ of running Glib/Gtk2 on libev).
+ - support for other languages (multiple C++ interfaces, D, Ruby,
+ Python) available from third-parties.
+
+ Examples of programs that embed libev: the EV perl module, node.js,
+ auditd, rxvt-unicode, gvpe (GNU Virtual Private Ethernet), the
+ Deliantra MMORPG server (http://www.deliantra.net/), Rubinius (a
+ next-generation Ruby VM), the Ebb web server, the Rev event toolkit.
+
+
+CONTRIBUTORS
+
+ libev was written and designed by Marc Lehmann and Emanuele Giaquinta.
+
+ The following people sent in patches or made other noteworthy
+ contributions to the design (for minor patches, see the Changes
+ file. If I forgot to include you, please shout at me, it was an
+ accident):
+
+ W.C.A. Wijngaards
+ Christopher Layne
+ Chris Brody
+
diff --git a/3rdparty/libev/Symbols.ev b/3rdparty/libev/Symbols.ev
new file mode 100644
index 0000000..fe169fa
--- /dev/null
+++ b/3rdparty/libev/Symbols.ev
@@ -0,0 +1,73 @@
+ev_async_send
+ev_async_start
+ev_async_stop
+ev_backend
+ev_break
+ev_check_start
+ev_check_stop
+ev_child_start
+ev_child_stop
+ev_cleanup_start
+ev_cleanup_stop
+ev_clear_pending
+ev_default_loop
+ev_default_loop_ptr
+ev_depth
+ev_embeddable_backends
+ev_embed_start
+ev_embed_stop
+ev_embed_sweep
+ev_feed_event
+ev_feed_fd_event
+ev_feed_signal
+ev_feed_signal_event
+ev_fork_start
+ev_fork_stop
+ev_idle_start
+ev_idle_stop
+ev_invoke
+ev_invoke_pending
+ev_io_start
+ev_io_stop
+ev_iteration
+ev_loop_destroy
+ev_loop_fork
+ev_loop_new
+ev_now
+ev_now_update
+ev_once
+ev_pending_count
+ev_periodic_again
+ev_periodic_start
+ev_periodic_stop
+ev_prepare_start
+ev_prepare_stop
+ev_recommended_backends
+ev_ref
+ev_resume
+ev_run
+ev_set_allocator
+ev_set_invoke_pending_cb
+ev_set_io_collect_interval
+ev_set_loop_release_cb
+ev_set_syserr_cb
+ev_set_timeout_collect_interval
+ev_set_userdata
+ev_signal_start
+ev_signal_stop
+ev_sleep
+ev_stat_start
+ev_stat_stat
+ev_stat_stop
+ev_supported_backends
+ev_suspend
+ev_time
+ev_timer_again
+ev_timer_remaining
+ev_timer_start
+ev_timer_stop
+ev_unref
+ev_userdata
+ev_verify
+ev_version_major
+ev_version_minor
diff --git a/3rdparty/libev/Symbols.event b/3rdparty/libev/Symbols.event
new file mode 100644
index 0000000..799d424
--- /dev/null
+++ b/3rdparty/libev/Symbols.event
@@ -0,0 +1,24 @@
+event_active
+event_add
+event_base_dispatch
+event_base_free
+event_base_get_method
+event_base_loop
+event_base_loopexit
+event_base_new
+event_base_once
+event_base_priority_init
+event_base_set
+event_del
+event_dispatch
+event_get_callback
+event_get_method
+event_get_version
+event_init
+event_loop
+event_loopexit
+event_once
+event_pending
+event_priority_init
+event_priority_set
+event_set
diff --git a/3rdparty/libev/TODO b/3rdparty/libev/TODO
new file mode 100644
index 0000000..a9d2c91
--- /dev/null
+++ b/3rdparty/libev/TODO
@@ -0,0 +1,14 @@
+TODO: ev_loop_wakeup
+TODO: EV_STANDALONE == NO_HASSLE (do not use clock_gettime in ev_standalone)
+TODO: faq, process a thing in each iteration
+TODO: dbeugging tips, ev_verify, ev_init twice
+TODO: ev_break for immediate exit (EVBREAK_NOW?)
+TODO: ev_feed_child_event
+TODO: document the special problem of signals around fork.
+TODO: store pid for each signal
+TODO: document file descriptor usage per loop
+TODO: store loop pid_t and compare isndie signal handler,store 1 for same, 2 for differign pid, clean up in loop_fork
+TODO: embed watchers need updating when fd changes
+TODO: document portability requirements for atomic pointer access
+TODO: document requirements for function pointers and calling conventions.
+
diff --git a/3rdparty/libev/cmake_config.h.in b/3rdparty/libev/cmake_config.h.in
new file mode 100644
index 0000000..ed0555c
--- /dev/null
+++ b/3rdparty/libev/cmake_config.h.in
@@ -0,0 +1,141 @@
+/* config.h.in. Generated from configure.ac by autoheader. */
+
+/* Define to 1 if you have the `clock_gettime' function. */
+#cmakedefine HAVE_CLOCK_GETTIME 1
+
+/* Define to 1 to use the syscall interface for clock_gettime */
+#cmakedefine HAVE_CLOCK_SYSCALL 1
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#cmakedefine HAVE_DLFCN_H 1
+
+/* Define to 1 if you have the `epoll_ctl' function. */
+#cmakedefine HAVE_EPOLL_CTL 1
+
+/* Define to 1 if you have the `eventfd' function. */
+#cmakedefine HAVE_EVENTFD 1
+
+/* Define to 1 if the floor function is available */
+#cmakedefine HAVE_FLOOR 1
+
+/* Define to 1 if you have the `inotify_init' function. */
+#cmakedefine HAVE_INOTIFY_INIT 1
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#cmakedefine HAVE_INTTYPES_H 1
+
+/* Define to 1 if you have the `kqueue' function. */
+#cmakedefine HAVE_KQUEUE 1
+
+/* Define to 1 if you have the `rt' library (-lrt). */
+#cmakedefine HAVE_LIBRT 1
+
+/* Define to 1 if you have the <memory.h> header file. */
+#cmakedefine HAVE_MEMORY_H 1
+
+/* Define to 1 if you have the `nanosleep' function. */
+#cmakedefine HAVE_NANOSLEEP 1
+
+/* Define to 1 if you have the `poll' function. */
+#cmakedefine HAVE_POLL 1
+
+/* Define to 1 if you have the <poll.h> header file. */
+#cmakedefine HAVE_POLL_H 1
+
+/* Define to 1 if you have the `port_create' function. */
+#cmakedefine HAVE_PORT_CREATE 1
+
+/* Define to 1 if you have the <port.h> header file. */
+#cmakedefine HAVE_PORT_H 1
+
+/* Define to 1 if you have the `select' function. */
+#cmakedefine HAVE_SELECT 1
+
+/* Define to 1 if you have the `signalfd' function. */
+#cmakedefine HAVE_SIGNALFD 1
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#cmakedefine HAVE_STDINT_H 1
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#cmakedefine HAVE_STDLIB_H 1
+
+/* Define to 1 if you have the <strings.h> header file. */
+#cmakedefine HAVE_STRINGS_H 1
+
+/* Define to 1 if you have the <string.h> header file. */
+#cmakedefine HAVE_STRING_H 1
+
+/* Define to 1 if you have the <sys/epoll.h> header file. */
+#cmakedefine HAVE_SYS_EPOLL_H 1
+
+/* Define to 1 if you have the <sys/eventfd.h> header file. */
+#cmakedefine HAVE_SYS_EVENTFD_H 1
+
+/* Define to 1 if you have the <sys/event.h> header file. */
+#cmakedefine HAVE_SYS_EVENT_H 1
+
+/* Define to 1 if you have the <sys/inotify.h> header file. */
+#cmakedefine HAVE_SYS_INOTIFY_H 1
+
+/* Define to 1 if you have the <sys/select.h> header file. */
+#cmakedefine HAVE_SYS_SELECT_H 1
+
+/* Define to 1 if you have the <sys/signalfd.h> header file. */
+#cmakedefine HAVE_SYS_SIGNALFD_H 1
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#cmakedefine HAVE_SYS_STAT_H 1
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#cmakedefine HAVE_SYS_TYPES_H 1
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#cmakedefine HAVE_UNISTD_H 1
+
+/* Define to 1 if you have the <linux/aio_abi.h> header file. */
+#cmakedefine HAVE_LINUX_AIO_ABI_H 1
+
+
+/* Define to the sub-directory where libtool stores uninstalled libraries. */
+#cmakedefine LT_OBJDIR
+
+/* Name of package */
+#cmakedefine PACKAGE
+
+/* Define to the address where bug reports for this package should be sent. */
+#cmakedefine PACKAGE_BUGREPORT
+
+/* Define to the full name of this package. */
+#cmakedefine PACKAGE_NAME
+
+/* Define to the full name and version of this package. */
+#cmakedefine PACKAGE_STRING
+
+/* Define to the one symbol short name of this package. */
+#cmakedefine PACKAGE_TARNAME
+
+/* Define to the home page for this package. */
+#cmakedefine PACKAGE_URL
+
+/* Define to the version of this package. */
+#cmakedefine PACKAGE_VERSION
+
+/* Define to 1 if you have the ANSI C header files. */
+#cmakedefine STDC_HEADERS
+
+/* Define to 1 if you have the <linux/aio_abi.h> header file. */
+#cmakedefine HAVE_LINUX_AIO_ABI_H 0
+
+/* Define to 1 if linux/fs.h defined kernel_rwf_t */
+#cmakedefine HAVE_KERNEL_RWF_T 0
+
+/* Define to 1 if you have the <linux/fs.h> header file. */
+#cmakedefine HAVE_LINUX_FS_H 0
+
+/* Define to 1 if you have the <sys/timerfd.h> header file. */
+#cmakedefine HAVE_SYS_TIMERFD_H 0
+
+
+/* Version number of package */
+#cmakedefine VERSION "@libev_VERSION_MAJOR@.@libev_VERSION_MINOR@"
diff --git a/3rdparty/libev/ev++.h b/3rdparty/libev/ev++.h
new file mode 100644
index 0000000..22dfcf5
--- /dev/null
+++ b/3rdparty/libev/ev++.h
@@ -0,0 +1,818 @@
+/*
+ * libev simple C++ wrapper classes
+ *
+ * Copyright (c) 2007,2008,2010,2018,2020 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#ifndef EVPP_H__
+#define EVPP_H__
+
+#ifdef EV_H
+# include EV_H
+#else
+# include "ev.h"
+#endif
+
+#ifndef EV_USE_STDEXCEPT
+# define EV_USE_STDEXCEPT 1
+#endif
+
+#if EV_USE_STDEXCEPT
+# include <stdexcept>
+#endif
+
+namespace ev {
+
+ typedef ev_tstamp tstamp;
+
+ enum {
+ UNDEF = EV_UNDEF,
+ NONE = EV_NONE,
+ READ = EV_READ,
+ WRITE = EV_WRITE,
+#if EV_COMPAT3
+ TIMEOUT = EV_TIMEOUT,
+#endif
+ TIMER = EV_TIMER,
+ PERIODIC = EV_PERIODIC,
+ SIGNAL = EV_SIGNAL,
+ CHILD = EV_CHILD,
+ STAT = EV_STAT,
+ IDLE = EV_IDLE,
+ CHECK = EV_CHECK,
+ PREPARE = EV_PREPARE,
+ FORK = EV_FORK,
+ ASYNC = EV_ASYNC,
+ EMBED = EV_EMBED,
+# undef ERROR // some systems stupidly #define ERROR
+ ERROR = EV_ERROR
+ };
+
+ enum
+ {
+ AUTO = EVFLAG_AUTO,
+ NOENV = EVFLAG_NOENV,
+ FORKCHECK = EVFLAG_FORKCHECK,
+
+ SELECT = EVBACKEND_SELECT,
+ POLL = EVBACKEND_POLL,
+ EPOLL = EVBACKEND_EPOLL,
+ KQUEUE = EVBACKEND_KQUEUE,
+ DEVPOLL = EVBACKEND_DEVPOLL,
+ PORT = EVBACKEND_PORT
+ };
+
+ enum
+ {
+#if EV_COMPAT3
+ NONBLOCK = EVLOOP_NONBLOCK,
+ ONESHOT = EVLOOP_ONESHOT,
+#endif
+ NOWAIT = EVRUN_NOWAIT,
+ ONCE = EVRUN_ONCE
+ };
+
+ enum how_t
+ {
+ ONE = EVBREAK_ONE,
+ ALL = EVBREAK_ALL
+ };
+
+ struct bad_loop
+#if EV_USE_STDEXCEPT
+ : std::exception
+#endif
+ {
+#if EV_USE_STDEXCEPT
+ const char *what () const EV_NOEXCEPT
+ {
+ return "libev event loop cannot be initialized, bad value of LIBEV_FLAGS?";
+ }
+#endif
+ };
+
+#ifdef EV_AX
+# undef EV_AX
+#endif
+
+#ifdef EV_AX_
+# undef EV_AX_
+#endif
+
+#if EV_MULTIPLICITY
+# define EV_AX raw_loop
+# define EV_AX_ raw_loop,
+#else
+# define EV_AX
+# define EV_AX_
+#endif
+
+ struct loop_ref
+ {
+ loop_ref (EV_P) EV_NOEXCEPT
+#if EV_MULTIPLICITY
+ : EV_AX (EV_A)
+#endif
+ {
+ }
+
+ bool operator == (const loop_ref &other) const EV_NOEXCEPT
+ {
+#if EV_MULTIPLICITY
+ return EV_AX == other.EV_AX;
+#else
+ return true;
+#endif
+ }
+
+ bool operator != (const loop_ref &other) const EV_NOEXCEPT
+ {
+#if EV_MULTIPLICITY
+ return ! (*this == other);
+#else
+ return false;
+#endif
+ }
+
+#if EV_MULTIPLICITY
+ bool operator == (const EV_P) const EV_NOEXCEPT
+ {
+ return this->EV_AX == EV_A;
+ }
+
+ bool operator != (const EV_P) const EV_NOEXCEPT
+ {
+ return ! (*this == EV_A);
+ }
+
+ operator struct ev_loop * () const EV_NOEXCEPT
+ {
+ return EV_AX;
+ }
+
+ operator const struct ev_loop * () const EV_NOEXCEPT
+ {
+ return EV_AX;
+ }
+
+ bool is_default () const EV_NOEXCEPT
+ {
+ return EV_AX == ev_default_loop (0);
+ }
+#endif
+
+#if EV_COMPAT3
+ void loop (int flags = 0)
+ {
+ ev_run (EV_AX_ flags);
+ }
+
+ void unloop (how_t how = ONE) EV_NOEXCEPT
+ {
+ ev_break (EV_AX_ how);
+ }
+#endif
+
+ void run (int flags = 0)
+ {
+ ev_run (EV_AX_ flags);
+ }
+
+ void break_loop (how_t how = ONE) EV_NOEXCEPT
+ {
+ ev_break (EV_AX_ how);
+ }
+
+ void post_fork () EV_NOEXCEPT
+ {
+ ev_loop_fork (EV_AX);
+ }
+
+ unsigned int backend () const EV_NOEXCEPT
+ {
+ return ev_backend (EV_AX);
+ }
+
+ tstamp now () const EV_NOEXCEPT
+ {
+ return ev_now (EV_AX);
+ }
+
+ void ref () EV_NOEXCEPT
+ {
+ ev_ref (EV_AX);
+ }
+
+ void unref () EV_NOEXCEPT
+ {
+ ev_unref (EV_AX);
+ }
+
+#if EV_FEATURE_API
+ unsigned int iteration () const EV_NOEXCEPT
+ {
+ return ev_iteration (EV_AX);
+ }
+
+ unsigned int depth () const EV_NOEXCEPT
+ {
+ return ev_depth (EV_AX);
+ }
+
+ void set_io_collect_interval (tstamp interval) EV_NOEXCEPT
+ {
+ ev_set_io_collect_interval (EV_AX_ interval);
+ }
+
+ void set_timeout_collect_interval (tstamp interval) EV_NOEXCEPT
+ {
+ ev_set_timeout_collect_interval (EV_AX_ interval);
+ }
+#endif
+
+ // function callback
+ void once (int fd, int events, tstamp timeout, void (*cb)(int, void *), void *arg = 0) EV_NOEXCEPT
+ {
+ ev_once (EV_AX_ fd, events, timeout, cb, arg);
+ }
+
+ // method callback
+ template<class K, void (K::*method)(int)>
+ void once (int fd, int events, tstamp timeout, K *object) EV_NOEXCEPT
+ {
+ once (fd, events, timeout, method_thunk<K, method>, object);
+ }
+
+ // default method == operator ()
+ template<class K>
+ void once (int fd, int events, tstamp timeout, K *object) EV_NOEXCEPT
+ {
+ once (fd, events, timeout, method_thunk<K, &K::operator ()>, object);
+ }
+
+ template<class K, void (K::*method)(int)>
+ static void method_thunk (int revents, void *arg)
+ {
+ (static_cast<K *>(arg)->*method)
+ (revents);
+ }
+
+ // no-argument method callback
+ template<class K, void (K::*method)()>
+ void once (int fd, int events, tstamp timeout, K *object) EV_NOEXCEPT
+ {
+ once (fd, events, timeout, method_noargs_thunk<K, method>, object);
+ }
+
+ template<class K, void (K::*method)()>
+ static void method_noargs_thunk (int revents, void *arg)
+ {
+ (static_cast<K *>(arg)->*method)
+ ();
+ }
+
+ // simpler function callback
+ template<void (*cb)(int)>
+ void once (int fd, int events, tstamp timeout) EV_NOEXCEPT
+ {
+ once (fd, events, timeout, simpler_func_thunk<cb>);
+ }
+
+ template<void (*cb)(int)>
+ static void simpler_func_thunk (int revents, void *arg)
+ {
+ (*cb)
+ (revents);
+ }
+
+ // simplest function callback
+ template<void (*cb)()>
+ void once (int fd, int events, tstamp timeout) EV_NOEXCEPT
+ {
+ once (fd, events, timeout, simplest_func_thunk<cb>);
+ }
+
+ template<void (*cb)()>
+ static void simplest_func_thunk (int revents, void *arg)
+ {
+ (*cb)
+ ();
+ }
+
+ void feed_fd_event (int fd, int revents) EV_NOEXCEPT
+ {
+ ev_feed_fd_event (EV_AX_ fd, revents);
+ }
+
+ void feed_signal_event (int signum) EV_NOEXCEPT
+ {
+ ev_feed_signal_event (EV_AX_ signum);
+ }
+
+#if EV_MULTIPLICITY
+ struct ev_loop* EV_AX;
+#endif
+
+ };
+
+#if EV_MULTIPLICITY
+ struct dynamic_loop : loop_ref
+ {
+
+ dynamic_loop (unsigned int flags = AUTO)
+ : loop_ref (ev_loop_new (flags))
+ {
+ if (!EV_AX)
+ throw bad_loop ();
+ }
+
+ ~dynamic_loop () EV_NOEXCEPT
+ {
+ ev_loop_destroy (EV_AX);
+ EV_AX = 0;
+ }
+
+ private:
+
+ dynamic_loop (const dynamic_loop &);
+
+ dynamic_loop & operator= (const dynamic_loop &);
+
+ };
+#endif
+
+ struct default_loop : loop_ref
+ {
+ default_loop (unsigned int flags = AUTO)
+#if EV_MULTIPLICITY
+ : loop_ref (ev_default_loop (flags))
+#endif
+ {
+ if (
+#if EV_MULTIPLICITY
+ !EV_AX
+#else
+ !ev_default_loop (flags)
+#endif
+ )
+ throw bad_loop ();
+ }
+
+ private:
+ default_loop (const default_loop &);
+ default_loop &operator = (const default_loop &);
+ };
+
+ inline loop_ref get_default_loop () EV_NOEXCEPT
+ {
+#if EV_MULTIPLICITY
+ return ev_default_loop (0);
+#else
+ return loop_ref ();
+#endif
+ }
+
+#undef EV_AX
+#undef EV_AX_
+
+#undef EV_PX
+#undef EV_PX_
+#if EV_MULTIPLICITY
+# define EV_PX loop_ref EV_A
+# define EV_PX_ loop_ref EV_A_
+#else
+# define EV_PX
+# define EV_PX_
+#endif
+
+ template<class ev_watcher, class watcher>
+ struct base : ev_watcher
+ {
+ // scoped pause/unpause of a watcher
+ struct freeze_guard
+ {
+ watcher &w;
+ bool active;
+
+ freeze_guard (watcher *self) EV_NOEXCEPT
+ : w (*self), active (w.is_active ())
+ {
+ if (active) w.stop ();
+ }
+
+ ~freeze_guard ()
+ {
+ if (active) w.start ();
+ }
+ };
+
+ #if EV_MULTIPLICITY
+ EV_PX;
+
+ // loop set
+ void set (EV_P) EV_NOEXCEPT
+ {
+ this->EV_A = EV_A;
+ }
+ #endif
+
+ base (EV_PX) EV_NOEXCEPT
+ #if EV_MULTIPLICITY
+ : EV_A (EV_A)
+ #endif
+ {
+ ev_init (this, 0);
+ }
+
+ void set_ (const void *data, void (*cb)(EV_P_ ev_watcher *w, int revents)) EV_NOEXCEPT
+ {
+ this->data = (void *)data;
+ ev_set_cb (static_cast<ev_watcher *>(this), cb);
+ }
+
+ // function callback
+ template<void (*function)(watcher &w, int)>
+ void set (void *data = 0) EV_NOEXCEPT
+ {
+ set_ (data, function_thunk<function>);
+ }
+
+ template<void (*function)(watcher &w, int)>
+ static void function_thunk (EV_P_ ev_watcher *w, int revents)
+ {
+ function
+ (*static_cast<watcher *>(w), revents);
+ }
+
+ // method callback
+ template<class K, void (K::*method)(watcher &w, int)>
+ void set (K *object) EV_NOEXCEPT
+ {
+ set_ (object, method_thunk<K, method>);
+ }
+
+ // default method == operator ()
+ template<class K>
+ void set (K *object) EV_NOEXCEPT
+ {
+ set_ (object, method_thunk<K, &K::operator ()>);
+ }
+
+ template<class K, void (K::*method)(watcher &w, int)>
+ static void method_thunk (EV_P_ ev_watcher *w, int revents)
+ {
+ (static_cast<K *>(w->data)->*method)
+ (*static_cast<watcher *>(w), revents);
+ }
+
+ // no-argument callback
+ template<class K, void (K::*method)()>
+ void set (K *object) EV_NOEXCEPT
+ {
+ set_ (object, method_noargs_thunk<K, method>);
+ }
+
+ template<class K, void (K::*method)()>
+ static void method_noargs_thunk (EV_P_ ev_watcher *w, int revents)
+ {
+ (static_cast<K *>(w->data)->*method)
+ ();
+ }
+
+ void operator ()(int events = EV_UNDEF)
+ {
+ return
+ ev_cb (static_cast<ev_watcher *>(this))
+ (static_cast<ev_watcher *>(this), events);
+ }
+
+ bool is_active () const EV_NOEXCEPT
+ {
+ return ev_is_active (static_cast<const ev_watcher *>(this));
+ }
+
+ bool is_pending () const EV_NOEXCEPT
+ {
+ return ev_is_pending (static_cast<const ev_watcher *>(this));
+ }
+
+ void feed_event (int revents) EV_NOEXCEPT
+ {
+ ev_feed_event (EV_A_ static_cast<ev_watcher *>(this), revents);
+ }
+ };
+
+ inline tstamp now (EV_P) EV_NOEXCEPT
+ {
+ return ev_now (EV_A);
+ }
+
+ inline void delay (tstamp interval) EV_NOEXCEPT
+ {
+ ev_sleep (interval);
+ }
+
+ inline int version_major () EV_NOEXCEPT
+ {
+ return ev_version_major ();
+ }
+
+ inline int version_minor () EV_NOEXCEPT
+ {
+ return ev_version_minor ();
+ }
+
+ inline unsigned int supported_backends () EV_NOEXCEPT
+ {
+ return ev_supported_backends ();
+ }
+
+ inline unsigned int recommended_backends () EV_NOEXCEPT
+ {
+ return ev_recommended_backends ();
+ }
+
+ inline unsigned int embeddable_backends () EV_NOEXCEPT
+ {
+ return ev_embeddable_backends ();
+ }
+
+ inline void set_allocator (void *(*cb)(void *ptr, long size) EV_NOEXCEPT) EV_NOEXCEPT
+ {
+ ev_set_allocator (cb);
+ }
+
+ inline void set_syserr_cb (void (*cb)(const char *msg) EV_NOEXCEPT) EV_NOEXCEPT
+ {
+ ev_set_syserr_cb (cb);
+ }
+
+ #if EV_MULTIPLICITY
+ #define EV_CONSTRUCT(cppstem,cstem) \
+ (EV_PX = get_default_loop ()) EV_NOEXCEPT \
+ : base<ev_ ## cstem, cppstem> (EV_A) \
+ { \
+ }
+ #else
+ #define EV_CONSTRUCT(cppstem,cstem) \
+ () EV_NOEXCEPT \
+ { \
+ }
+ #endif
+
+ /* using a template here would require quite a few more lines,
+ * so a macro solution was chosen */
+ #define EV_BEGIN_WATCHER(cppstem,cstem) \
+ \
+ struct cppstem : base<ev_ ## cstem, cppstem> \
+ { \
+ void start () EV_NOEXCEPT \
+ { \
+ ev_ ## cstem ## _start (EV_A_ static_cast<ev_ ## cstem *>(this)); \
+ } \
+ \
+ void stop () EV_NOEXCEPT \
+ { \
+ ev_ ## cstem ## _stop (EV_A_ static_cast<ev_ ## cstem *>(this)); \
+ } \
+ \
+ cppstem EV_CONSTRUCT(cppstem,cstem) \
+ \
+ ~cppstem () EV_NOEXCEPT \
+ { \
+ stop (); \
+ } \
+ \
+ using base<ev_ ## cstem, cppstem>::set; \
+ \
+ private: \
+ \
+ cppstem (const cppstem &o); \
+ \
+ cppstem &operator =(const cppstem &o); \
+ \
+ public:
+
+ #define EV_END_WATCHER(cppstem,cstem) \
+ };
+
+ EV_BEGIN_WATCHER (io, io)
+ void set (int fd, int events) EV_NOEXCEPT
+ {
+ freeze_guard freeze (this);
+ ev_io_set (static_cast<ev_io *>(this), fd, events);
+ }
+
+ void set (int events) EV_NOEXCEPT
+ {
+ freeze_guard freeze (this);
+ ev_io_modify (static_cast<ev_io *>(this), events);
+ }
+
+ void start (int fd, int events) EV_NOEXCEPT
+ {
+ set (fd, events);
+ start ();
+ }
+ EV_END_WATCHER (io, io)
+
+ EV_BEGIN_WATCHER (timer, timer)
+ void set (ev_tstamp after, ev_tstamp repeat = 0.) EV_NOEXCEPT
+ {
+ freeze_guard freeze (this);
+ ev_timer_set (static_cast<ev_timer *>(this), after, repeat);
+ }
+
+ void start (ev_tstamp after, ev_tstamp repeat = 0.) EV_NOEXCEPT
+ {
+ set (after, repeat);
+ start ();
+ }
+
+ void again () EV_NOEXCEPT
+ {
+ ev_timer_again (EV_A_ static_cast<ev_timer *>(this));
+ }
+
+ ev_tstamp remaining ()
+ {
+ return ev_timer_remaining (EV_A_ static_cast<ev_timer *>(this));
+ }
+ EV_END_WATCHER (timer, timer)
+
+ #if EV_PERIODIC_ENABLE
+ EV_BEGIN_WATCHER (periodic, periodic)
+ void set (ev_tstamp at, ev_tstamp interval = 0.) EV_NOEXCEPT
+ {
+ freeze_guard freeze (this);
+ ev_periodic_set (static_cast<ev_periodic *>(this), at, interval, 0);
+ }
+
+ void start (ev_tstamp at, ev_tstamp interval = 0.) EV_NOEXCEPT
+ {
+ set (at, interval);
+ start ();
+ }
+
+ void again () EV_NOEXCEPT
+ {
+ ev_periodic_again (EV_A_ static_cast<ev_periodic *>(this));
+ }
+ EV_END_WATCHER (periodic, periodic)
+ #endif
+
+ #if EV_SIGNAL_ENABLE
+ EV_BEGIN_WATCHER (sig, signal)
+ void set (int signum) EV_NOEXCEPT
+ {
+ freeze_guard freeze (this);
+ ev_signal_set (static_cast<ev_signal *>(this), signum);
+ }
+
+ void start (int signum) EV_NOEXCEPT
+ {
+ set (signum);
+ start ();
+ }
+ EV_END_WATCHER (sig, signal)
+ #endif
+
+ #if EV_CHILD_ENABLE
+ EV_BEGIN_WATCHER (child, child)
+ void set (int pid, int trace = 0) EV_NOEXCEPT
+ {
+ freeze_guard freeze (this);
+ ev_child_set (static_cast<ev_child *>(this), pid, trace);
+ }
+
+ void start (int pid, int trace = 0) EV_NOEXCEPT
+ {
+ set (pid, trace);
+ start ();
+ }
+ EV_END_WATCHER (child, child)
+ #endif
+
+ #if EV_STAT_ENABLE
+ EV_BEGIN_WATCHER (stat, stat)
+ void set (const char *path, ev_tstamp interval = 0.) EV_NOEXCEPT
+ {
+ freeze_guard freeze (this);
+ ev_stat_set (static_cast<ev_stat *>(this), path, interval);
+ }
+
+ void start (const char *path, ev_tstamp interval = 0.) EV_NOEXCEPT
+ {
+ stop ();
+ set (path, interval);
+ start ();
+ }
+
+ void update () EV_NOEXCEPT
+ {
+ ev_stat_stat (EV_A_ static_cast<ev_stat *>(this));
+ }
+ EV_END_WATCHER (stat, stat)
+ #endif
+
+ #if EV_IDLE_ENABLE
+ EV_BEGIN_WATCHER (idle, idle)
+ void set () EV_NOEXCEPT { }
+ EV_END_WATCHER (idle, idle)
+ #endif
+
+ #if EV_PREPARE_ENABLE
+ EV_BEGIN_WATCHER (prepare, prepare)
+ void set () EV_NOEXCEPT { }
+ EV_END_WATCHER (prepare, prepare)
+ #endif
+
+ #if EV_CHECK_ENABLE
+ EV_BEGIN_WATCHER (check, check)
+ void set () EV_NOEXCEPT { }
+ EV_END_WATCHER (check, check)
+ #endif
+
+ #if EV_EMBED_ENABLE
+ EV_BEGIN_WATCHER (embed, embed)
+ void set_embed (struct ev_loop *embedded_loop) EV_NOEXCEPT
+ {
+ freeze_guard freeze (this);
+ ev_embed_set (static_cast<ev_embed *>(this), embedded_loop);
+ }
+
+ void start (struct ev_loop *embedded_loop) EV_NOEXCEPT
+ {
+ set (embedded_loop);
+ start ();
+ }
+
+ void sweep ()
+ {
+ ev_embed_sweep (EV_A_ static_cast<ev_embed *>(this));
+ }
+ EV_END_WATCHER (embed, embed)
+ #endif
+
+ #if EV_FORK_ENABLE
+ EV_BEGIN_WATCHER (fork, fork)
+ void set () EV_NOEXCEPT { }
+ EV_END_WATCHER (fork, fork)
+ #endif
+
+ #if EV_ASYNC_ENABLE
+ EV_BEGIN_WATCHER (async, async)
+ void send () EV_NOEXCEPT
+ {
+ ev_async_send (EV_A_ static_cast<ev_async *>(this));
+ }
+
+ bool async_pending () EV_NOEXCEPT
+ {
+ return ev_async_pending (static_cast<ev_async *>(this));
+ }
+ EV_END_WATCHER (async, async)
+ #endif
+
+ #undef EV_PX
+ #undef EV_PX_
+ #undef EV_CONSTRUCT
+ #undef EV_BEGIN_WATCHER
+ #undef EV_END_WATCHER
+}
+
+#endif
+
diff --git a/3rdparty/libev/ev.3 b/3rdparty/libev/ev.3
new file mode 100644
index 0000000..af578f0
--- /dev/null
+++ b/3rdparty/libev/ev.3
@@ -0,0 +1,5819 @@
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+.\"
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+.\"
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+. ds ^ \&
+. ds , \&
+. ds ~ ~
+. ds /
+.\}
+.if t \{\
+. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
+. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
+. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
+. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
+. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
+. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
+.\}
+. \" troff and (daisy-wheel) nroff accents
+.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
+.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
+.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
+.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
+.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
+.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
+.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
+.ds ae a\h'-(\w'a'u*4/10)'e
+.ds Ae A\h'-(\w'A'u*4/10)'E
+. \" corrections for vroff
+.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
+.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
+. \" for low resolution devices (crt and lpr)
+.if \n(.H>23 .if \n(.V>19 \
+\{\
+. ds : e
+. ds 8 ss
+. ds o a
+. ds d- d\h'-1'\(ga
+. ds D- D\h'-1'\(hy
+. ds th \o'bp'
+. ds Th \o'LP'
+. ds ae ae
+. ds Ae AE
+.\}
+.rm #[ #] #H #V #F C
+.\" ========================================================================
+.\"
+.IX Title "LIBEV 3"
+.TH LIBEV 3 "2020-03-12" "libev-4.31" "libev - high performance full featured event loop"
+.\" For nroff, turn off justification. Always turn off hyphenation; it makes
+.\" way too many mistakes in technical documents.
+.if n .ad l
+.nh
+.SH "NAME"
+libev \- a high performance full\-featured event loop written in C
+.SH "SYNOPSIS"
+.IX Header "SYNOPSIS"
+.Vb 1
+\& #include <ev.h>
+.Ve
+.SS "\s-1EXAMPLE PROGRAM\s0"
+.IX Subsection "EXAMPLE PROGRAM"
+.Vb 2
+\& // a single header file is required
+\& #include <ev.h>
+\&
+\& #include <stdio.h> // for puts
+\&
+\& // every watcher type has its own typedef\*(Aqd struct
+\& // with the name ev_TYPE
+\& ev_io stdin_watcher;
+\& ev_timer timeout_watcher;
+\&
+\& // all watcher callbacks have a similar signature
+\& // this callback is called when data is readable on stdin
+\& static void
+\& stdin_cb (EV_P_ ev_io *w, int revents)
+\& {
+\& puts ("stdin ready");
+\& // for one\-shot events, one must manually stop the watcher
+\& // with its corresponding stop function.
+\& ev_io_stop (EV_A_ w);
+\&
+\& // this causes all nested ev_run\*(Aqs to stop iterating
+\& ev_break (EV_A_ EVBREAK_ALL);
+\& }
+\&
+\& // another callback, this time for a time\-out
+\& static void
+\& timeout_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& puts ("timeout");
+\& // this causes the innermost ev_run to stop iterating
+\& ev_break (EV_A_ EVBREAK_ONE);
+\& }
+\&
+\& int
+\& main (void)
+\& {
+\& // use the default event loop unless you have special needs
+\& struct ev_loop *loop = EV_DEFAULT;
+\&
+\& // initialise an io watcher, then start it
+\& // this one will watch for stdin to become readable
+\& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
+\& ev_io_start (loop, &stdin_watcher);
+\&
+\& // initialise a timer watcher, then start it
+\& // simple non\-repeating 5.5 second timeout
+\& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+\& ev_timer_start (loop, &timeout_watcher);
+\&
+\& // now wait for events to arrive
+\& ev_run (loop, 0);
+\&
+\& // break was called, so exit
+\& return 0;
+\& }
+.Ve
+.SH "ABOUT THIS DOCUMENT"
+.IX Header "ABOUT THIS DOCUMENT"
+This document documents the libev software package.
+.PP
+The newest version of this document is also available as an html-formatted
+web page you might find easier to navigate when reading it for the first
+time: <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>.
+.PP
+While this document tries to be as complete as possible in documenting
+libev, its usage and the rationale behind its design, it is not a tutorial
+on event-based programming, nor will it introduce event-based programming
+with libev.
+.PP
+Familiarity with event based programming techniques in general is assumed
+throughout this document.
+.SH "WHAT TO READ WHEN IN A HURRY"
+.IX Header "WHAT TO READ WHEN IN A HURRY"
+This manual tries to be very detailed, but unfortunately, this also makes
+it very long. If you just want to know the basics of libev, I suggest
+reading \*(L"\s-1ANATOMY OF A WATCHER\*(R"\s0, then the \*(L"\s-1EXAMPLE PROGRAM\*(R"\s0 above and
+look up the missing functions in \*(L"\s-1GLOBAL FUNCTIONS\*(R"\s0 and the \f(CW\*(C`ev_io\*(C'\fR and
+\&\f(CW\*(C`ev_timer\*(C'\fR sections in \*(L"\s-1WATCHER TYPES\*(R"\s0.
+.SH "ABOUT LIBEV"
+.IX Header "ABOUT LIBEV"
+Libev is an event loop: you register interest in certain events (such as a
+file descriptor being readable or a timeout occurring), and it will manage
+these event sources and provide your program with events.
+.PP
+To do this, it must take more or less complete control over your process
+(or thread) by executing the \fIevent loop\fR handler, and will then
+communicate events via a callback mechanism.
+.PP
+You register interest in certain events by registering so-called \fIevent
+watchers\fR, which are relatively small C structures you initialise with the
+details of the event, and then hand it over to libev by \fIstarting\fR the
+watcher.
+.SS "\s-1FEATURES\s0"
+.IX Subsection "FEATURES"
+Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific aio and \f(CW\*(C`epoll\*(C'\fR
+interfaces, the BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port
+mechanisms for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR
+interface (for \f(CW\*(C`ev_stat\*(C'\fR), Linux eventfd/signalfd (for faster and cleaner
+inter-thread wakeup (\f(CW\*(C`ev_async\*(C'\fR)/signal handling (\f(CW\*(C`ev_signal\*(C'\fR)) relative
+timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers with customised rescheduling
+(\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals (\f(CW\*(C`ev_signal\*(C'\fR), process status
+change events (\f(CW\*(C`ev_child\*(C'\fR), and event watchers dealing with the event
+loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, \f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and
+\&\f(CW\*(C`ev_check\*(C'\fR watchers) as well as file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even
+limited support for fork events (\f(CW\*(C`ev_fork\*(C'\fR).
+.PP
+It also is quite fast (see this
+benchmark <http://libev.schmorp.de/bench.html> comparing it to libevent
+for example).
+.SS "\s-1CONVENTIONS\s0"
+.IX Subsection "CONVENTIONS"
+Libev is very configurable. In this manual the default (and most common)
+configuration will be described, which supports multiple event loops. For
+more info about various configuration options please have a look at
+\&\fB\s-1EMBED\s0\fR section in this manual. If libev was configured without support
+for multiple event loops, then all functions taking an initial argument of
+name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have
+this argument.
+.SS "\s-1TIME REPRESENTATION\s0"
+.IX Subsection "TIME REPRESENTATION"
+Libev represents time as a single floating point number, representing
+the (fractional) number of seconds since the (\s-1POSIX\s0) epoch (in practice
+somewhere near the beginning of 1970, details are complicated, don't
+ask). This type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use
+too. It usually aliases to the \f(CW\*(C`double\*(C'\fR type in C. When you need to do
+any calculations on it, you should treat it as some floating point value.
+.PP
+Unlike the name component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for
+time differences (e.g. delays) throughout libev.
+.SH "ERROR HANDLING"
+.IX Header "ERROR HANDLING"
+Libev knows three classes of errors: operating system errors, usage errors
+and internal errors (bugs).
+.PP
+When libev catches an operating system error it cannot handle (for example
+a system call indicating a condition libev cannot fix), it calls the callback
+set via \f(CW\*(C`ev_set_syserr_cb\*(C'\fR, which is supposed to fix the problem or
+abort. The default is to print a diagnostic message and to call \f(CW\*(C`abort
+()\*(C'\fR.
+.PP
+When libev detects a usage error such as a negative timer interval, then
+it will print a diagnostic message and abort (via the \f(CW\*(C`assert\*(C'\fR mechanism,
+so \f(CW\*(C`NDEBUG\*(C'\fR will disable this checking): these are programming errors in
+the libev caller and need to be fixed there.
+.PP
+Via the \f(CW\*(C`EV_FREQUENT\*(C'\fR macro you can compile in and/or enable extensive
+consistency checking code inside libev that can be used to check for
+internal inconsistencies, suually caused by application bugs.
+.PP
+Libev also has a few internal error-checking \f(CW\*(C`assert\*(C'\fRions. These do not
+trigger under normal circumstances, as they indicate either a bug in libev
+or worse.
+.SH "GLOBAL FUNCTIONS"
+.IX Header "GLOBAL FUNCTIONS"
+These functions can be called anytime, even before initialising the
+library in any way.
+.IP "ev_tstamp ev_time ()" 4
+.IX Item "ev_tstamp ev_time ()"
+Returns the current time as libev would use it. Please note that the
+\&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp
+you actually want to know. Also interesting is the combination of
+\&\f(CW\*(C`ev_now_update\*(C'\fR and \f(CW\*(C`ev_now\*(C'\fR.
+.IP "ev_sleep (ev_tstamp interval)" 4
+.IX Item "ev_sleep (ev_tstamp interval)"
+Sleep for the given interval: The current thread will be blocked
+until either it is interrupted or the given time interval has
+passed (approximately \- it might return a bit earlier even if not
+interrupted). Returns immediately if \f(CW\*(C`interval <= 0\*(C'\fR.
+.Sp
+Basically this is a sub-second-resolution \f(CW\*(C`sleep ()\*(C'\fR.
+.Sp
+The range of the \f(CW\*(C`interval\*(C'\fR is limited \- libev only guarantees to work
+with sleep times of up to one day (\f(CW\*(C`interval <= 86400\*(C'\fR).
+.IP "int ev_version_major ()" 4
+.IX Item "int ev_version_major ()"
+.PD 0
+.IP "int ev_version_minor ()" 4
+.IX Item "int ev_version_minor ()"
+.PD
+You can find out the major and minor \s-1ABI\s0 version numbers of the library
+you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and
+\&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global
+symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the
+version of the library your program was compiled against.
+.Sp
+These version numbers refer to the \s-1ABI\s0 version of the library, not the
+release version.
+.Sp
+Usually, it's a good idea to terminate if the major versions mismatch,
+as this indicates an incompatible change. Minor versions are usually
+compatible to older versions, so a larger minor version alone is usually
+not a problem.
+.Sp
+Example: Make sure we haven't accidentally been linked against the wrong
+version (note, however, that this will not detect other \s-1ABI\s0 mismatches,
+such as \s-1LFS\s0 or reentrancy).
+.Sp
+.Vb 3
+\& assert (("libev version mismatch",
+\& ev_version_major () == EV_VERSION_MAJOR
+\& && ev_version_minor () >= EV_VERSION_MINOR));
+.Ve
+.IP "unsigned int ev_supported_backends ()" 4
+.IX Item "unsigned int ev_supported_backends ()"
+Return the set of all backends (i.e. their corresponding \f(CW\*(C`EV_BACKEND_*\*(C'\fR
+value) compiled into this binary of libev (independent of their
+availability on the system you are running on). See \f(CW\*(C`ev_default_loop\*(C'\fR for
+a description of the set values.
+.Sp
+Example: make sure we have the epoll method, because yeah this is cool and
+a must have and can we have a torrent of it please!!!11
+.Sp
+.Vb 2
+\& assert (("sorry, no epoll, no sex",
+\& ev_supported_backends () & EVBACKEND_EPOLL));
+.Ve
+.IP "unsigned int ev_recommended_backends ()" 4
+.IX Item "unsigned int ev_recommended_backends ()"
+Return the set of all backends compiled into this binary of libev and
+also recommended for this platform, meaning it will work for most file
+descriptor types. This set is often smaller than the one returned by
+\&\f(CW\*(C`ev_supported_backends\*(C'\fR, as for example kqueue is broken on most BSDs
+and will not be auto-detected unless you explicitly request it (assuming
+you know what you are doing). This is the set of backends that libev will
+probe for if you specify no backends explicitly.
+.IP "unsigned int ev_embeddable_backends ()" 4
+.IX Item "unsigned int ev_embeddable_backends ()"
+Returns the set of backends that are embeddable in other event loops. This
+value is platform-specific but can include backends not available on the
+current system. To find which embeddable backends might be supported on
+the current system, you would need to look at \f(CW\*(C`ev_embeddable_backends ()
+& ev_supported_backends ()\*(C'\fR, likewise for recommended ones.
+.Sp
+See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info.
+.IP "ev_set_allocator (void *(*cb)(void *ptr, long size) throw ())" 4
+.IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size) throw ())"
+Sets the allocation function to use (the prototype is similar \- the
+semantics are identical to the \f(CW\*(C`realloc\*(C'\fR C89/SuS/POSIX function). It is
+used to allocate and free memory (no surprises here). If it returns zero
+when memory needs to be allocated (\f(CW\*(C`size != 0\*(C'\fR), the library might abort
+or take some potentially destructive action.
+.Sp
+Since some systems (at least OpenBSD and Darwin) fail to implement
+correct \f(CW\*(C`realloc\*(C'\fR semantics, libev will use a wrapper around the system
+\&\f(CW\*(C`realloc\*(C'\fR and \f(CW\*(C`free\*(C'\fR functions by default.
+.Sp
+You could override this function in high-availability programs to, say,
+free some memory if it cannot allocate memory, to use a special allocator,
+or even to sleep a while and retry until some memory is available.
+.Sp
+Example: The following is the \f(CW\*(C`realloc\*(C'\fR function that libev itself uses
+which should work with \f(CW\*(C`realloc\*(C'\fR and \f(CW\*(C`free\*(C'\fR functions of all kinds and
+is probably a good basis for your own implementation.
+.Sp
+.Vb 5
+\& static void *
+\& ev_realloc_emul (void *ptr, long size) EV_NOEXCEPT
+\& {
+\& if (size)
+\& return realloc (ptr, size);
+\&
+\& free (ptr);
+\& return 0;
+\& }
+.Ve
+.Sp
+Example: Replace the libev allocator with one that waits a bit and then
+retries.
+.Sp
+.Vb 8
+\& static void *
+\& persistent_realloc (void *ptr, size_t size)
+\& {
+\& if (!size)
+\& {
+\& free (ptr);
+\& return 0;
+\& }
+\&
+\& for (;;)
+\& {
+\& void *newptr = realloc (ptr, size);
+\&
+\& if (newptr)
+\& return newptr;
+\&
+\& sleep (60);
+\& }
+\& }
+\&
+\& ...
+\& ev_set_allocator (persistent_realloc);
+.Ve
+.IP "ev_set_syserr_cb (void (*cb)(const char *msg) throw ())" 4
+.IX Item "ev_set_syserr_cb (void (*cb)(const char *msg) throw ())"
+Set the callback function to call on a retryable system call error (such
+as failed select, poll, epoll_wait). The message is a printable string
+indicating the system call or subsystem causing the problem. If this
+callback is set, then libev will expect it to remedy the situation, no
+matter what, when it returns. That is, libev will generally retry the
+requested operation, or, if the condition doesn't go away, do bad stuff
+(such as abort).
+.Sp
+Example: This is basically the same thing that libev does internally, too.
+.Sp
+.Vb 6
+\& static void
+\& fatal_error (const char *msg)
+\& {
+\& perror (msg);
+\& abort ();
+\& }
+\&
+\& ...
+\& ev_set_syserr_cb (fatal_error);
+.Ve
+.IP "ev_feed_signal (int signum)" 4
+.IX Item "ev_feed_signal (int signum)"
+This function can be used to \*(L"simulate\*(R" a signal receive. It is completely
+safe to call this function at any time, from any context, including signal
+handlers or random threads.
+.Sp
+Its main use is to customise signal handling in your process, especially
+in the presence of threads. For example, you could block signals
+by default in all threads (and specifying \f(CW\*(C`EVFLAG_NOSIGMASK\*(C'\fR when
+creating any loops), and in one thread, use \f(CW\*(C`sigwait\*(C'\fR or any other
+mechanism to wait for signals, then \*(L"deliver\*(R" them to libev by calling
+\&\f(CW\*(C`ev_feed_signal\*(C'\fR.
+.SH "FUNCTIONS CONTROLLING EVENT LOOPS"
+.IX Header "FUNCTIONS CONTROLLING EVENT LOOPS"
+An event loop is described by a \f(CW\*(C`struct ev_loop *\*(C'\fR (the \f(CW\*(C`struct\*(C'\fR is
+\&\fInot\fR optional in this case unless libev 3 compatibility is disabled, as
+libev 3 had an \f(CW\*(C`ev_loop\*(C'\fR function colliding with the struct name).
+.PP
+The library knows two types of such loops, the \fIdefault\fR loop, which
+supports child process events, and dynamically created event loops which
+do not.
+.IP "struct ev_loop *ev_default_loop (unsigned int flags)" 4
+.IX Item "struct ev_loop *ev_default_loop (unsigned int flags)"
+This returns the \*(L"default\*(R" event loop object, which is what you should
+normally use when you just need \*(L"the event loop\*(R". Event loop objects and
+the \f(CW\*(C`flags\*(C'\fR parameter are described in more detail in the entry for
+\&\f(CW\*(C`ev_loop_new\*(C'\fR.
+.Sp
+If the default loop is already initialised then this function simply
+returns it (and ignores the flags. If that is troubling you, check
+\&\f(CW\*(C`ev_backend ()\*(C'\fR afterwards). Otherwise it will create it with the given
+flags, which should almost always be \f(CW0\fR, unless the caller is also the
+one calling \f(CW\*(C`ev_run\*(C'\fR or otherwise qualifies as \*(L"the main program\*(R".
+.Sp
+If you don't know what event loop to use, use the one returned from this
+function (or via the \f(CW\*(C`EV_DEFAULT\*(C'\fR macro).
+.Sp
+Note that this function is \fInot\fR thread-safe, so if you want to use it
+from multiple threads, you have to employ some kind of mutex (note also
+that this case is unlikely, as loops cannot be shared easily between
+threads anyway).
+.Sp
+The default loop is the only loop that can handle \f(CW\*(C`ev_child\*(C'\fR watchers,
+and to do this, it always registers a handler for \f(CW\*(C`SIGCHLD\*(C'\fR. If this is
+a problem for your application you can either create a dynamic loop with
+\&\f(CW\*(C`ev_loop_new\*(C'\fR which doesn't do that, or you can simply overwrite the
+\&\f(CW\*(C`SIGCHLD\*(C'\fR signal handler \fIafter\fR calling \f(CW\*(C`ev_default_init\*(C'\fR.
+.Sp
+Example: This is the most typical usage.
+.Sp
+.Vb 2
+\& if (!ev_default_loop (0))
+\& fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
+.Ve
+.Sp
+Example: Restrict libev to the select and poll backends, and do not allow
+environment settings to be taken into account:
+.Sp
+.Vb 1
+\& ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
+.Ve
+.IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4
+.IX Item "struct ev_loop *ev_loop_new (unsigned int flags)"
+This will create and initialise a new event loop object. If the loop
+could not be initialised, returns false.
+.Sp
+This function is thread-safe, and one common way to use libev with
+threads is indeed to create one loop per thread, and using the default
+loop in the \*(L"main\*(R" or \*(L"initial\*(R" thread.
+.Sp
+The flags argument can be used to specify special behaviour or specific
+backends to use, and is usually specified as \f(CW0\fR (or \f(CW\*(C`EVFLAG_AUTO\*(C'\fR).
+.Sp
+The following flags are supported:
+.RS 4
+.ie n .IP """EVFLAG_AUTO""" 4
+.el .IP "\f(CWEVFLAG_AUTO\fR" 4
+.IX Item "EVFLAG_AUTO"
+The default flags value. Use this if you have no clue (it's the right
+thing, believe me).
+.ie n .IP """EVFLAG_NOENV""" 4
+.el .IP "\f(CWEVFLAG_NOENV\fR" 4
+.IX Item "EVFLAG_NOENV"
+If this flag bit is or'ed into the flag value (or the program runs setuid
+or setgid) then libev will \fInot\fR look at the environment variable
+\&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will
+override the flags completely if it is found in the environment. This is
+useful to try out specific backends to test their performance, to work
+around bugs, or to make libev threadsafe (accessing environment variables
+cannot be done in a threadsafe way, but usually it works if no other
+thread modifies them).
+.ie n .IP """EVFLAG_FORKCHECK""" 4
+.el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4
+.IX Item "EVFLAG_FORKCHECK"
+Instead of calling \f(CW\*(C`ev_loop_fork\*(C'\fR manually after a fork, you can also
+make libev check for a fork in each iteration by enabling this flag.
+.Sp
+This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop,
+and thus this might slow down your event loop if you do a lot of loop
+iterations and little real work, but is usually not noticeable (on my
+GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn
+sequence without a system call and thus \fIvery\fR fast, but my GNU/Linux
+system also has \f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). (Update: glibc
+versions 2.25 apparently removed the \f(CW\*(C`getpid\*(C'\fR optimisation again).
+.Sp
+The big advantage of this flag is that you can forget about fork (and
+forget about forgetting to tell libev about forking, although you still
+have to ignore \f(CW\*(C`SIGPIPE\*(C'\fR) when you use this flag.
+.Sp
+This flag setting cannot be overridden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR
+environment variable.
+.ie n .IP """EVFLAG_NOINOTIFY""" 4
+.el .IP "\f(CWEVFLAG_NOINOTIFY\fR" 4
+.IX Item "EVFLAG_NOINOTIFY"
+When this flag is specified, then libev will not attempt to use the
+\&\fIinotify\fR \s-1API\s0 for its \f(CW\*(C`ev_stat\*(C'\fR watchers. Apart from debugging and
+testing, this flag can be useful to conserve inotify file descriptors, as
+otherwise each loop using \f(CW\*(C`ev_stat\*(C'\fR watchers consumes one inotify handle.
+.ie n .IP """EVFLAG_SIGNALFD""" 4
+.el .IP "\f(CWEVFLAG_SIGNALFD\fR" 4
+.IX Item "EVFLAG_SIGNALFD"
+When this flag is specified, then libev will attempt to use the
+\&\fIsignalfd\fR \s-1API\s0 for its \f(CW\*(C`ev_signal\*(C'\fR (and \f(CW\*(C`ev_child\*(C'\fR) watchers. This \s-1API\s0
+delivers signals synchronously, which makes it both faster and might make
+it possible to get the queued signal data. It can also simplify signal
+handling with threads, as long as you properly block signals in your
+threads that are not interested in handling them.
+.Sp
+Signalfd will not be used by default as this changes your signal mask, and
+there are a lot of shoddy libraries and programs (glib's threadpool for
+example) that can't properly initialise their signal masks.
+.ie n .IP """EVFLAG_NOSIGMASK""" 4
+.el .IP "\f(CWEVFLAG_NOSIGMASK\fR" 4
+.IX Item "EVFLAG_NOSIGMASK"
+When this flag is specified, then libev will avoid to modify the signal
+mask. Specifically, this means you have to make sure signals are unblocked
+when you want to receive them.
+.Sp
+This behaviour is useful when you want to do your own signal handling, or
+want to handle signals only in specific threads and want to avoid libev
+unblocking the signals.
+.Sp
+It's also required by \s-1POSIX\s0 in a threaded program, as libev calls
+\&\f(CW\*(C`sigprocmask\*(C'\fR, whose behaviour is officially unspecified.
+.ie n .IP """EVFLAG_NOTIMERFD""" 4
+.el .IP "\f(CWEVFLAG_NOTIMERFD\fR" 4
+.IX Item "EVFLAG_NOTIMERFD"
+When this flag is specified, the libev will avoid using a \f(CW\*(C`timerfd\*(C'\fR to
+detect time jumps. It will still be able to detect time jumps, but takes
+longer and has a lower accuracy in doing so, but saves a file descriptor
+per loop.
+.Sp
+The current implementation only tries to use a \f(CW\*(C`timerfd\*(C'\fR when the first
+\&\f(CW\*(C`ev_periodic\*(C'\fR watcher is started and falls back on other methods if it
+cannot be created, but this behaviour might change in the future.
+.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4
+.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4
+.IX Item "EVBACKEND_SELECT (value 1, portable select backend)"
+This is your standard \fBselect\fR\|(2) backend. Not \fIcompletely\fR standard, as
+libev tries to roll its own fd_set with no limits on the number of fds,
+but if that fails, expect a fairly low limit on the number of fds when
+using this backend. It doesn't scale too well (O(highest_fd)), but its
+usually the fastest backend for a low number of (low-numbered :) fds.
+.Sp
+To get good performance out of this backend you need a high amount of
+parallelism (most of the file descriptors should be busy). If you are
+writing a server, you should \f(CW\*(C`accept ()\*(C'\fR in a loop to accept as many
+connections as possible during one iteration. You might also want to have
+a look at \f(CW\*(C`ev_set_io_collect_interval ()\*(C'\fR to increase the amount of
+readiness notifications you get per iteration.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR to the \f(CW\*(C`readfds\*(C'\fR set and \f(CW\*(C`EV_WRITE\*(C'\fR to the
+\&\f(CW\*(C`writefds\*(C'\fR set (and to work around Microsoft Windows bugs, also onto the
+\&\f(CW\*(C`exceptfds\*(C'\fR set on that platform).
+.ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4
+.el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4
+.IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)"
+And this is your standard \fBpoll\fR\|(2) backend. It's more complicated
+than select, but handles sparse fds better and has no artificial
+limit on the number of fds you can use (except it will slow down
+considerably with a lot of inactive fds). It scales similarly to select,
+i.e. O(total_fds). See the entry for \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR, above, for
+performance tips.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR to \f(CW\*(C`POLLIN | POLLERR | POLLHUP\*(C'\fR, and
+\&\f(CW\*(C`EV_WRITE\*(C'\fR to \f(CW\*(C`POLLOUT | POLLERR | POLLHUP\*(C'\fR.
+.ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4
+.el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4
+.IX Item "EVBACKEND_EPOLL (value 4, Linux)"
+Use the Linux-specific \fBepoll\fR\|(7) interface (for both pre\- and post\-2.6.9
+kernels).
+.Sp
+For few fds, this backend is a bit little slower than poll and select, but
+it scales phenomenally better. While poll and select usually scale like
+O(total_fds) where total_fds is the total number of fds (or the highest
+fd), epoll scales either O(1) or O(active_fds).
+.Sp
+The epoll mechanism deserves honorable mention as the most misdesigned
+of the more advanced event mechanisms: mere annoyances include silently
+dropping file descriptors, requiring a system call per change per file
+descriptor (and unnecessary guessing of parameters), problems with dup,
+returning before the timeout value, resulting in additional iterations
+(and only giving 5ms accuracy while select on the same platform gives
+0.1ms) and so on. The biggest issue is fork races, however \- if a program
+forks then \fIboth\fR parent and child process have to recreate the epoll
+set, which can take considerable time (one syscall per file descriptor)
+and is of course hard to detect.
+.Sp
+Epoll is also notoriously buggy \- embedding epoll fds \fIshould\fR work,
+but of course \fIdoesn't\fR, and epoll just loves to report events for
+totally \fIdifferent\fR file descriptors (even already closed ones, so
+one cannot even remove them from the set) than registered in the set
+(especially on \s-1SMP\s0 systems). Libev tries to counter these spurious
+notifications by employing an additional generation counter and comparing
+that against the events to filter out spurious ones, recreating the set
+when required. Epoll also erroneously rounds down timeouts, but gives you
+no way to know when and by how much, so sometimes you have to busy-wait
+because epoll returns immediately despite a nonzero timeout. And last
+not least, it also refuses to work with some file descriptors which work
+perfectly fine with \f(CW\*(C`select\*(C'\fR (files, many character devices...).
+.Sp
+Epoll is truly the train wreck among event poll mechanisms, a frankenpoll,
+cobbled together in a hurry, no thought to design or interaction with
+others. Oh, the pain, will it ever stop...
+.Sp
+While stopping, setting and starting an I/O watcher in the same iteration
+will result in some caching, there is still a system call per such
+incident (because the same \fIfile descriptor\fR could point to a different
+\&\fIfile description\fR now), so its best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed
+file descriptors might not work very well if you register events for both
+file descriptors.
+.Sp
+Best performance from this backend is achieved by not unregistering all
+watchers for a file descriptor until it has been closed, if possible,
+i.e. keep at least one watcher active per fd at all times. Stopping and
+starting a watcher (without re-setting it) also usually doesn't cause
+extra overhead. A fork can both result in spurious notifications as well
+as in libev having to destroy and recreate the epoll object, which can
+take considerable time and thus should be avoided.
+.Sp
+All this means that, in practice, \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR can be as fast or
+faster than epoll for maybe up to a hundred file descriptors, depending on
+the usage. So sad.
+.Sp
+While nominally embeddable in other event loops, this feature is broken in
+a lot of kernel revisions, but probably(!) works in current versions.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as
+\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
+.ie n .IP """EVBACKEND_LINUXAIO"" (value 64, Linux)" 4
+.el .IP "\f(CWEVBACKEND_LINUXAIO\fR (value 64, Linux)" 4
+.IX Item "EVBACKEND_LINUXAIO (value 64, Linux)"
+Use the Linux-specific Linux \s-1AIO\s0 (\fInot\fR \f(CWaio(7)\fR but \f(CWio_submit(2)\fR) event interface available in post\-4.18 kernels (but libev
+only tries to use it in 4.19+).
+.Sp
+This is another Linux train wreck of an event interface.
+.Sp
+If this backend works for you (as of this writing, it was very
+experimental), it is the best event interface available on Linux and might
+be well worth enabling it \- if it isn't available in your kernel this will
+be detected and this backend will be skipped.
+.Sp
+This backend can batch oneshot requests and supports a user-space ring
+buffer to receive events. It also doesn't suffer from most of the design
+problems of epoll (such as not being able to remove event sources from
+the epoll set), and generally sounds too good to be true. Because, this
+being the Linux kernel, of course it suffers from a whole new set of
+limitations, forcing you to fall back to epoll, inheriting all its design
+issues.
+.Sp
+For one, it is not easily embeddable (but probably could be done using
+an event fd at some extra overhead). It also is subject to a system wide
+limit that can be configured in \fI/proc/sys/fs/aio\-max\-nr\fR. If no \s-1AIO\s0
+requests are left, this backend will be skipped during initialisation, and
+will switch to epoll when the loop is active.
+.Sp
+Most problematic in practice, however, is that not all file descriptors
+work with it. For example, in Linux 5.1, \s-1TCP\s0 sockets, pipes, event fds,
+files, \fI/dev/null\fR and many others are supported, but ttys do not work
+properly (a known bug that the kernel developers don't care about, see
+<https://lore.kernel.org/patchwork/patch/1047453/>), so this is not
+(yet?) a generic event polling interface.
+.Sp
+Overall, it seems the Linux developers just don't want it to have a
+generic event handling mechanism other than \f(CW\*(C`select\*(C'\fR or \f(CW\*(C`poll\*(C'\fR.
+.Sp
+To work around all these problem, the current version of libev uses its
+epoll backend as a fallback for file descriptor types that do not work. Or
+falls back completely to epoll if the kernel acts up.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as
+\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
+.ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4
+.el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4
+.IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)"
+Kqueue deserves special mention, as at the time this backend was
+implemented, it was broken on all BSDs except NetBSD (usually it doesn't
+work reliably with anything but sockets and pipes, except on Darwin,
+where of course it's completely useless). Unlike epoll, however, whose
+brokenness is by design, these kqueue bugs can be (and mostly have been)
+fixed without \s-1API\s0 changes to existing programs. For this reason it's not
+being \*(L"auto-detected\*(R" on all platforms unless you explicitly specify it
+in the flags (i.e. using \f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a
+known-to-be-good (\-enough) system like NetBSD.
+.Sp
+You still can embed kqueue into a normal poll or select backend and use it
+only for sockets (after having made sure that sockets work with kqueue on
+the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info.
+.Sp
+It scales in the same way as the epoll backend, but the interface to the
+kernel is more efficient (which says nothing about its actual speed, of
+course). While stopping, setting and starting an I/O watcher does never
+cause an extra system call as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to
+two event changes per incident. Support for \f(CW\*(C`fork ()\*(C'\fR is very bad (you
+might have to leak fds on fork, but it's more sane than epoll) and it
+drops fds silently in similarly hard-to-detect cases.
+.Sp
+This backend usually performs well under most conditions.
+.Sp
+While nominally embeddable in other event loops, this doesn't work
+everywhere, so you might need to test for this. And since it is broken
+almost everywhere, you should only use it when you have a lot of sockets
+(for which it usually works), by embedding it into another event loop
+(e.g. \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR (but \f(CW\*(C`poll\*(C'\fR is of course
+also broken on \s-1OS X\s0)) and, did I mention it, using it only for sockets.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR into an \f(CW\*(C`EVFILT_READ\*(C'\fR kevent with
+\&\f(CW\*(C`NOTE_EOF\*(C'\fR, and \f(CW\*(C`EV_WRITE\*(C'\fR into an \f(CW\*(C`EVFILT_WRITE\*(C'\fR kevent with
+\&\f(CW\*(C`NOTE_EOF\*(C'\fR.
+.ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4
+.el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4
+.IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)"
+This is not implemented yet (and might never be, unless you send me an
+implementation). According to reports, \f(CW\*(C`/dev/poll\*(C'\fR only supports sockets
+and is not embeddable, which would limit the usefulness of this backend
+immensely.
+.ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4
+.el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4
+.IX Item "EVBACKEND_PORT (value 32, Solaris 10)"
+This uses the Solaris 10 event port mechanism. As with everything on Solaris,
+it's really slow, but it still scales very well (O(active_fds)).
+.Sp
+While this backend scales well, it requires one system call per active
+file descriptor per loop iteration. For small and medium numbers of file
+descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend
+might perform better.
+.Sp
+On the positive side, this backend actually performed fully to
+specification in all tests and is fully embeddable, which is a rare feat
+among the OS-specific backends (I vastly prefer correctness over speed
+hacks).
+.Sp
+On the negative side, the interface is \fIbizarre\fR \- so bizarre that
+even sun itself gets it wrong in their code examples: The event polling
+function sometimes returns events to the caller even though an error
+occurred, but with no indication whether it has done so or not (yes, it's
+even documented that way) \- deadly for edge-triggered interfaces where you
+absolutely have to know whether an event occurred or not because you have
+to re-arm the watcher.
+.Sp
+Fortunately libev seems to be able to work around these idiocies.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as
+\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
+.ie n .IP """EVBACKEND_ALL""" 4
+.el .IP "\f(CWEVBACKEND_ALL\fR" 4
+.IX Item "EVBACKEND_ALL"
+Try all backends (even potentially broken ones that wouldn't be tried
+with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as
+\&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR.
+.Sp
+It is definitely not recommended to use this flag, use whatever
+\&\f(CW\*(C`ev_recommended_backends ()\*(C'\fR returns, or simply do not specify a backend
+at all.
+.ie n .IP """EVBACKEND_MASK""" 4
+.el .IP "\f(CWEVBACKEND_MASK\fR" 4
+.IX Item "EVBACKEND_MASK"
+Not a backend at all, but a mask to select all backend bits from a
+\&\f(CW\*(C`flags\*(C'\fR value, in case you want to mask out any backends from a flags
+value (e.g. when modifying the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR environment variable).
+.RE
+.RS 4
+.Sp
+If one or more of the backend flags are or'ed into the flags value,
+then only these backends will be tried (in the reverse order as listed
+here). If none are specified, all backends in \f(CW\*(C`ev_recommended_backends
+()\*(C'\fR will be tried.
+.Sp
+Example: Try to create a event loop that uses epoll and nothing else.
+.Sp
+.Vb 3
+\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
+\& if (!epoller)
+\& fatal ("no epoll found here, maybe it hides under your chair");
+.Ve
+.Sp
+Example: Use whatever libev has to offer, but make sure that kqueue is
+used if available.
+.Sp
+.Vb 1
+\& struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
+.Ve
+.Sp
+Example: Similarly, on linux, you mgiht want to take advantage of the
+linux aio backend if possible, but fall back to something else if that
+isn't available.
+.Sp
+.Vb 1
+\& struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_LINUXAIO);
+.Ve
+.RE
+.IP "ev_loop_destroy (loop)" 4
+.IX Item "ev_loop_destroy (loop)"
+Destroys an event loop object (frees all memory and kernel state
+etc.). None of the active event watchers will be stopped in the normal
+sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your
+responsibility to either stop all watchers cleanly yourself \fIbefore\fR
+calling this function, or cope with the fact afterwards (which is usually
+the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them
+for example).
+.Sp
+Note that certain global state, such as signal state (and installed signal
+handlers), will not be freed by this function, and related watchers (such
+as signal and child watchers) would need to be stopped manually.
+.Sp
+This function is normally used on loop objects allocated by
+\&\f(CW\*(C`ev_loop_new\*(C'\fR, but it can also be used on the default loop returned by
+\&\f(CW\*(C`ev_default_loop\*(C'\fR, in which case it is not thread-safe.
+.Sp
+Note that it is not advisable to call this function on the default loop
+except in the rare occasion where you really need to free its resources.
+If you need dynamically allocated loops it is better to use \f(CW\*(C`ev_loop_new\*(C'\fR
+and \f(CW\*(C`ev_loop_destroy\*(C'\fR.
+.IP "ev_loop_fork (loop)" 4
+.IX Item "ev_loop_fork (loop)"
+This function sets a flag that causes subsequent \f(CW\*(C`ev_run\*(C'\fR iterations
+to reinitialise the kernel state for backends that have one. Despite
+the name, you can call it anytime you are allowed to start or stop
+watchers (except inside an \f(CW\*(C`ev_prepare\*(C'\fR callback), but it makes most
+sense after forking, in the child process. You \fImust\fR call it (or use
+\&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR) in the child before resuming or calling \f(CW\*(C`ev_run\*(C'\fR.
+.Sp
+In addition, if you want to reuse a loop (via this function or
+\&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR), you \fIalso\fR have to ignore \f(CW\*(C`SIGPIPE\*(C'\fR.
+.Sp
+Again, you \fIhave\fR to call it on \fIany\fR loop that you want to re-use after
+a fork, \fIeven if you do not plan to use the loop in the parent\fR. This is
+because some kernel interfaces *cough* \fIkqueue\fR *cough* do funny things
+during fork.
+.Sp
+On the other hand, you only need to call this function in the child
+process if and only if you want to use the event loop in the child. If
+you just fork+exec or create a new loop in the child, you don't have to
+call it at all (in fact, \f(CW\*(C`epoll\*(C'\fR is so badly broken that it makes a
+difference, but libev will usually detect this case on its own and do a
+costly reset of the backend).
+.Sp
+The function itself is quite fast and it's usually not a problem to call
+it just in case after a fork.
+.Sp
+Example: Automate calling \f(CW\*(C`ev_loop_fork\*(C'\fR on the default loop when
+using pthreads.
+.Sp
+.Vb 5
+\& static void
+\& post_fork_child (void)
+\& {
+\& ev_loop_fork (EV_DEFAULT);
+\& }
+\&
+\& ...
+\& pthread_atfork (0, 0, post_fork_child);
+.Ve
+.IP "int ev_is_default_loop (loop)" 4
+.IX Item "int ev_is_default_loop (loop)"
+Returns true when the given loop is, in fact, the default loop, and false
+otherwise.
+.IP "unsigned int ev_iteration (loop)" 4
+.IX Item "unsigned int ev_iteration (loop)"
+Returns the current iteration count for the event loop, which is identical
+to the number of times libev did poll for new events. It starts at \f(CW0\fR
+and happily wraps around with enough iterations.
+.Sp
+This value can sometimes be useful as a generation counter of sorts (it
+\&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with
+\&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls \- and is incremented between the
+prepare and check phases.
+.IP "unsigned int ev_depth (loop)" 4
+.IX Item "unsigned int ev_depth (loop)"
+Returns the number of times \f(CW\*(C`ev_run\*(C'\fR was entered minus the number of
+times \f(CW\*(C`ev_run\*(C'\fR was exited normally, in other words, the recursion depth.
+.Sp
+Outside \f(CW\*(C`ev_run\*(C'\fR, this number is zero. In a callback, this number is
+\&\f(CW1\fR, unless \f(CW\*(C`ev_run\*(C'\fR was invoked recursively (or from another thread),
+in which case it is higher.
+.Sp
+Leaving \f(CW\*(C`ev_run\*(C'\fR abnormally (setjmp/longjmp, cancelling the thread,
+throwing an exception etc.), doesn't count as \*(L"exit\*(R" \- consider this
+as a hint to avoid such ungentleman-like behaviour unless it's really
+convenient, in which case it is fully supported.
+.IP "unsigned int ev_backend (loop)" 4
+.IX Item "unsigned int ev_backend (loop)"
+Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in
+use.
+.IP "ev_tstamp ev_now (loop)" 4
+.IX Item "ev_tstamp ev_now (loop)"
+Returns the current \*(L"event loop time\*(R", which is the time the event loop
+received events and started processing them. This timestamp does not
+change as long as callbacks are being processed, and this is also the base
+time used for relative timers. You can treat it as the timestamp of the
+event occurring (or more correctly, libev finding out about it).
+.IP "ev_now_update (loop)" 4
+.IX Item "ev_now_update (loop)"
+Establishes the current time by querying the kernel, updating the time
+returned by \f(CW\*(C`ev_now ()\*(C'\fR in the progress. This is a costly operation and
+is usually done automatically within \f(CW\*(C`ev_run ()\*(C'\fR.
+.Sp
+This function is rarely useful, but when some event callback runs for a
+very long time without entering the event loop, updating libev's idea of
+the current time is a good idea.
+.Sp
+See also \*(L"The special problem of time updates\*(R" in the \f(CW\*(C`ev_timer\*(C'\fR section.
+.IP "ev_suspend (loop)" 4
+.IX Item "ev_suspend (loop)"
+.PD 0
+.IP "ev_resume (loop)" 4
+.IX Item "ev_resume (loop)"
+.PD
+These two functions suspend and resume an event loop, for use when the
+loop is not used for a while and timeouts should not be processed.
+.Sp
+A typical use case would be an interactive program such as a game: When
+the user presses \f(CW\*(C`^Z\*(C'\fR to suspend the game and resumes it an hour later it
+would be best to handle timeouts as if no time had actually passed while
+the program was suspended. This can be achieved by calling \f(CW\*(C`ev_suspend\*(C'\fR
+in your \f(CW\*(C`SIGTSTP\*(C'\fR handler, sending yourself a \f(CW\*(C`SIGSTOP\*(C'\fR and calling
+\&\f(CW\*(C`ev_resume\*(C'\fR directly afterwards to resume timer processing.
+.Sp
+Effectively, all \f(CW\*(C`ev_timer\*(C'\fR watchers will be delayed by the time spend
+between \f(CW\*(C`ev_suspend\*(C'\fR and \f(CW\*(C`ev_resume\*(C'\fR, and all \f(CW\*(C`ev_periodic\*(C'\fR watchers
+will be rescheduled (that is, they will lose any events that would have
+occurred while suspended).
+.Sp
+After calling \f(CW\*(C`ev_suspend\*(C'\fR you \fBmust not\fR call \fIany\fR function on the
+given loop other than \f(CW\*(C`ev_resume\*(C'\fR, and you \fBmust not\fR call \f(CW\*(C`ev_resume\*(C'\fR
+without a previous call to \f(CW\*(C`ev_suspend\*(C'\fR.
+.Sp
+Calling \f(CW\*(C`ev_suspend\*(C'\fR/\f(CW\*(C`ev_resume\*(C'\fR has the side effect of updating the
+event loop time (see \f(CW\*(C`ev_now_update\*(C'\fR).
+.IP "bool ev_run (loop, int flags)" 4
+.IX Item "bool ev_run (loop, int flags)"
+Finally, this is it, the event handler. This function usually is called
+after you have initialised all your watchers and you want to start
+handling events. It will ask the operating system for any new events, call
+the watcher callbacks, and then repeat the whole process indefinitely: This
+is why event loops are called \fIloops\fR.
+.Sp
+If the flags argument is specified as \f(CW0\fR, it will keep handling events
+until either no event watchers are active anymore or \f(CW\*(C`ev_break\*(C'\fR was
+called.
+.Sp
+The return value is false if there are no more active watchers (which
+usually means \*(L"all jobs done\*(R" or \*(L"deadlock\*(R"), and true in all other cases
+(which usually means " you should call \f(CW\*(C`ev_run\*(C'\fR again").
+.Sp
+Please note that an explicit \f(CW\*(C`ev_break\*(C'\fR is usually better than
+relying on all watchers to be stopped when deciding when a program has
+finished (especially in interactive programs), but having a program
+that automatically loops as long as it has to and no longer by virtue
+of relying on its watchers stopping correctly, that is truly a thing of
+beauty.
+.Sp
+This function is \fImostly\fR exception-safe \- you can break out of a
+\&\f(CW\*(C`ev_run\*(C'\fR call by calling \f(CW\*(C`longjmp\*(C'\fR in a callback, throwing a \*(C+
+exception and so on. This does not decrement the \f(CW\*(C`ev_depth\*(C'\fR value, nor
+will it clear any outstanding \f(CW\*(C`EVBREAK_ONE\*(C'\fR breaks.
+.Sp
+A flags value of \f(CW\*(C`EVRUN_NOWAIT\*(C'\fR will look for new events, will handle
+those events and any already outstanding ones, but will not wait and
+block your process in case there are no events and will return after one
+iteration of the loop. This is sometimes useful to poll and handle new
+events while doing lengthy calculations, to keep the program responsive.
+.Sp
+A flags value of \f(CW\*(C`EVRUN_ONCE\*(C'\fR will look for new events (waiting if
+necessary) and will handle those and any already outstanding ones. It
+will block your process until at least one new event arrives (which could
+be an event internal to libev itself, so there is no guarantee that a
+user-registered callback will be called), and will return after one
+iteration of the loop.
+.Sp
+This is useful if you are waiting for some external event in conjunction
+with something not expressible using other libev watchers (i.e. "roll your
+own \f(CW\*(C`ev_run\*(C'\fR"). However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is
+usually a better approach for this kind of thing.
+.Sp
+Here are the gory details of what \f(CW\*(C`ev_run\*(C'\fR does (this is for your
+understanding, not a guarantee that things will work exactly like this in
+future versions):
+.Sp
+.Vb 10
+\& \- Increment loop depth.
+\& \- Reset the ev_break status.
+\& \- Before the first iteration, call any pending watchers.
+\& LOOP:
+\& \- If EVFLAG_FORKCHECK was used, check for a fork.
+\& \- If a fork was detected (by any means), queue and call all fork watchers.
+\& \- Queue and call all prepare watchers.
+\& \- If ev_break was called, goto FINISH.
+\& \- If we have been forked, detach and recreate the kernel state
+\& as to not disturb the other process.
+\& \- Update the kernel state with all outstanding changes.
+\& \- Update the "event loop time" (ev_now ()).
+\& \- Calculate for how long to sleep or block, if at all
+\& (active idle watchers, EVRUN_NOWAIT or not having
+\& any active watchers at all will result in not sleeping).
+\& \- Sleep if the I/O and timer collect interval say so.
+\& \- Increment loop iteration counter.
+\& \- Block the process, waiting for any events.
+\& \- Queue all outstanding I/O (fd) events.
+\& \- Update the "event loop time" (ev_now ()), and do time jump adjustments.
+\& \- Queue all expired timers.
+\& \- Queue all expired periodics.
+\& \- Queue all idle watchers with priority higher than that of pending events.
+\& \- Queue all check watchers.
+\& \- Call all queued watchers in reverse order (i.e. check watchers first).
+\& Signals and child watchers are implemented as I/O watchers, and will
+\& be handled here by queueing them when their watcher gets executed.
+\& \- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
+\& were used, or there are no active watchers, goto FINISH, otherwise
+\& continue with step LOOP.
+\& FINISH:
+\& \- Reset the ev_break status iff it was EVBREAK_ONE.
+\& \- Decrement the loop depth.
+\& \- Return.
+.Ve
+.Sp
+Example: Queue some jobs and then loop until no events are outstanding
+anymore.
+.Sp
+.Vb 4
+\& ... queue jobs here, make sure they register event watchers as long
+\& ... as they still have work to do (even an idle watcher will do..)
+\& ev_run (my_loop, 0);
+\& ... jobs done or somebody called break. yeah!
+.Ve
+.IP "ev_break (loop, how)" 4
+.IX Item "ev_break (loop, how)"
+Can be used to make a call to \f(CW\*(C`ev_run\*(C'\fR return early (but only after it
+has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either
+\&\f(CW\*(C`EVBREAK_ONE\*(C'\fR, which will make the innermost \f(CW\*(C`ev_run\*(C'\fR call return, or
+\&\f(CW\*(C`EVBREAK_ALL\*(C'\fR, which will make all nested \f(CW\*(C`ev_run\*(C'\fR calls return.
+.Sp
+This \*(L"break state\*(R" will be cleared on the next call to \f(CW\*(C`ev_run\*(C'\fR.
+.Sp
+It is safe to call \f(CW\*(C`ev_break\*(C'\fR from outside any \f(CW\*(C`ev_run\*(C'\fR calls, too, in
+which case it will have no effect.
+.IP "ev_ref (loop)" 4
+.IX Item "ev_ref (loop)"
+.PD 0
+.IP "ev_unref (loop)" 4
+.IX Item "ev_unref (loop)"
+.PD
+Ref/unref can be used to add or remove a reference count on the event
+loop: Every watcher keeps one reference, and as long as the reference
+count is nonzero, \f(CW\*(C`ev_run\*(C'\fR will not return on its own.
+.Sp
+This is useful when you have a watcher that you never intend to
+unregister, but that nevertheless should not keep \f(CW\*(C`ev_run\*(C'\fR from
+returning. In such a case, call \f(CW\*(C`ev_unref\*(C'\fR after starting, and \f(CW\*(C`ev_ref\*(C'\fR
+before stopping it.
+.Sp
+As an example, libev itself uses this for its internal signal pipe: It
+is not visible to the libev user and should not keep \f(CW\*(C`ev_run\*(C'\fR from
+exiting if no event watchers registered by it are active. It is also an
+excellent way to do this for generic recurring timers or from within
+third-party libraries. Just remember to \fIunref after start\fR and \fIref
+before stop\fR (but only if the watcher wasn't active before, or was active
+before, respectively. Note also that libev might stop watchers itself
+(e.g. non-repeating timers) in which case you have to \f(CW\*(C`ev_ref\*(C'\fR
+in the callback).
+.Sp
+Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_run\*(C'\fR
+running when nothing else is active.
+.Sp
+.Vb 4
+\& ev_signal exitsig;
+\& ev_signal_init (&exitsig, sig_cb, SIGINT);
+\& ev_signal_start (loop, &exitsig);
+\& ev_unref (loop);
+.Ve
+.Sp
+Example: For some weird reason, unregister the above signal handler again.
+.Sp
+.Vb 2
+\& ev_ref (loop);
+\& ev_signal_stop (loop, &exitsig);
+.Ve
+.IP "ev_set_io_collect_interval (loop, ev_tstamp interval)" 4
+.IX Item "ev_set_io_collect_interval (loop, ev_tstamp interval)"
+.PD 0
+.IP "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" 4
+.IX Item "ev_set_timeout_collect_interval (loop, ev_tstamp interval)"
+.PD
+These advanced functions influence the time that libev will spend waiting
+for events. Both time intervals are by default \f(CW0\fR, meaning that libev
+will try to invoke timer/periodic callbacks and I/O callbacks with minimum
+latency.
+.Sp
+Setting these to a higher value (the \f(CW\*(C`interval\*(C'\fR \fImust\fR be >= \f(CW0\fR)
+allows libev to delay invocation of I/O and timer/periodic callbacks
+to increase efficiency of loop iterations (or to increase power-saving
+opportunities).
+.Sp
+The idea is that sometimes your program runs just fast enough to handle
+one (or very few) event(s) per loop iteration. While this makes the
+program responsive, it also wastes a lot of \s-1CPU\s0 time to poll for new
+events, especially with backends like \f(CW\*(C`select ()\*(C'\fR which have a high
+overhead for the actual polling but can deliver many events at once.
+.Sp
+By setting a higher \fIio collect interval\fR you allow libev to spend more
+time collecting I/O events, so you can handle more events per iteration,
+at the cost of increasing latency. Timeouts (both \f(CW\*(C`ev_periodic\*(C'\fR and
+\&\f(CW\*(C`ev_timer\*(C'\fR) will not be affected. Setting this to a non-null value will
+introduce an additional \f(CW\*(C`ev_sleep ()\*(C'\fR call into most loop iterations. The
+sleep time ensures that libev will not poll for I/O events more often then
+once per this interval, on average (as long as the host time resolution is
+good enough).
+.Sp
+Likewise, by setting a higher \fItimeout collect interval\fR you allow libev
+to spend more time collecting timeouts, at the expense of increased
+latency/jitter/inexactness (the watcher callback will be called
+later). \f(CW\*(C`ev_io\*(C'\fR watchers will not be affected. Setting this to a non-null
+value will not introduce any overhead in libev.
+.Sp
+Many (busy) programs can usually benefit by setting the I/O collect
+interval to a value near \f(CW0.1\fR or so, which is often enough for
+interactive servers (of course not for games), likewise for timeouts. It
+usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR,
+as this approaches the timing granularity of most systems. Note that if
+you do transactions with the outside world and you can't increase the
+parallelity, then this setting will limit your transaction rate (if you
+need to poll once per transaction and the I/O collect interval is 0.01,
+then you can't do more than 100 transactions per second).
+.Sp
+Setting the \fItimeout collect interval\fR can improve the opportunity for
+saving power, as the program will \*(L"bundle\*(R" timer callback invocations that
+are \*(L"near\*(R" in time together, by delaying some, thus reducing the number of
+times the process sleeps and wakes up again. Another useful technique to
+reduce iterations/wake\-ups is to use \f(CW\*(C`ev_periodic\*(C'\fR watchers and make sure
+they fire on, say, one-second boundaries only.
+.Sp
+Example: we only need 0.1s timeout granularity, and we wish not to poll
+more often than 100 times per second:
+.Sp
+.Vb 2
+\& ev_set_timeout_collect_interval (EV_DEFAULT_UC_ 0.1);
+\& ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
+.Ve
+.IP "ev_invoke_pending (loop)" 4
+.IX Item "ev_invoke_pending (loop)"
+This call will simply invoke all pending watchers while resetting their
+pending state. Normally, \f(CW\*(C`ev_run\*(C'\fR does this automatically when required,
+but when overriding the invoke callback this call comes handy. This
+function can be invoked from a watcher \- this can be useful for example
+when you want to do some lengthy calculation and want to pass further
+event handling to another thread (you still have to make sure only one
+thread executes within \f(CW\*(C`ev_invoke_pending\*(C'\fR or \f(CW\*(C`ev_run\*(C'\fR of course).
+.IP "int ev_pending_count (loop)" 4
+.IX Item "int ev_pending_count (loop)"
+Returns the number of pending watchers \- zero indicates that no watchers
+are pending.
+.IP "ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(\s-1EV_P\s0))" 4
+.IX Item "ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))"
+This overrides the invoke pending functionality of the loop: Instead of
+invoking all pending watchers when there are any, \f(CW\*(C`ev_run\*(C'\fR will call
+this callback instead. This is useful, for example, when you want to
+invoke the actual watchers inside another context (another thread etc.).
+.Sp
+If you want to reset the callback, use \f(CW\*(C`ev_invoke_pending\*(C'\fR as new
+callback.
+.IP "ev_set_loop_release_cb (loop, void (*release)(\s-1EV_P\s0) throw (), void (*acquire)(\s-1EV_P\s0) throw ())" 4
+.IX Item "ev_set_loop_release_cb (loop, void (*release)(EV_P) throw (), void (*acquire)(EV_P) throw ())"
+Sometimes you want to share the same loop between multiple threads. This
+can be done relatively simply by putting mutex_lock/unlock calls around
+each call to a libev function.
+.Sp
+However, \f(CW\*(C`ev_run\*(C'\fR can run an indefinite time, so it is not feasible
+to wait for it to return. One way around this is to wake up the event
+loop via \f(CW\*(C`ev_break\*(C'\fR and \f(CW\*(C`ev_async_send\*(C'\fR, another way is to set these
+\&\fIrelease\fR and \fIacquire\fR callbacks on the loop.
+.Sp
+When set, then \f(CW\*(C`release\*(C'\fR will be called just before the thread is
+suspended waiting for new events, and \f(CW\*(C`acquire\*(C'\fR is called just
+afterwards.
+.Sp
+Ideally, \f(CW\*(C`release\*(C'\fR will just call your mutex_unlock function, and
+\&\f(CW\*(C`acquire\*(C'\fR will just call the mutex_lock function again.
+.Sp
+While event loop modifications are allowed between invocations of
+\&\f(CW\*(C`release\*(C'\fR and \f(CW\*(C`acquire\*(C'\fR (that's their only purpose after all), no
+modifications done will affect the event loop, i.e. adding watchers will
+have no effect on the set of file descriptors being watched, or the time
+waited. Use an \f(CW\*(C`ev_async\*(C'\fR watcher to wake up \f(CW\*(C`ev_run\*(C'\fR when you want it
+to take note of any changes you made.
+.Sp
+In theory, threads executing \f(CW\*(C`ev_run\*(C'\fR will be async-cancel safe between
+invocations of \f(CW\*(C`release\*(C'\fR and \f(CW\*(C`acquire\*(C'\fR.
+.Sp
+See also the locking example in the \f(CW\*(C`THREADS\*(C'\fR section later in this
+document.
+.IP "ev_set_userdata (loop, void *data)" 4
+.IX Item "ev_set_userdata (loop, void *data)"
+.PD 0
+.IP "void *ev_userdata (loop)" 4
+.IX Item "void *ev_userdata (loop)"
+.PD
+Set and retrieve a single \f(CW\*(C`void *\*(C'\fR associated with a loop. When
+\&\f(CW\*(C`ev_set_userdata\*(C'\fR has never been called, then \f(CW\*(C`ev_userdata\*(C'\fR returns
+\&\f(CW0\fR.
+.Sp
+These two functions can be used to associate arbitrary data with a loop,
+and are intended solely for the \f(CW\*(C`invoke_pending_cb\*(C'\fR, \f(CW\*(C`release\*(C'\fR and
+\&\f(CW\*(C`acquire\*(C'\fR callbacks described above, but of course can be (ab\-)used for
+any other purpose as well.
+.IP "ev_verify (loop)" 4
+.IX Item "ev_verify (loop)"
+This function only does something when \f(CW\*(C`EV_VERIFY\*(C'\fR support has been
+compiled in, which is the default for non-minimal builds. It tries to go
+through all internal structures and checks them for validity. If anything
+is found to be inconsistent, it will print an error message to standard
+error and call \f(CW\*(C`abort ()\*(C'\fR.
+.Sp
+This can be used to catch bugs inside libev itself: under normal
+circumstances, this function will never abort as of course libev keeps its
+data structures consistent.
+.SH "ANATOMY OF A WATCHER"
+.IX Header "ANATOMY OF A WATCHER"
+In the following description, uppercase \f(CW\*(C`TYPE\*(C'\fR in names stands for the
+watcher type, e.g. \f(CW\*(C`ev_TYPE_start\*(C'\fR can mean \f(CW\*(C`ev_timer_start\*(C'\fR for timer
+watchers and \f(CW\*(C`ev_io_start\*(C'\fR for I/O watchers.
+.PP
+A watcher is an opaque structure that you allocate and register to record
+your interest in some event. To make a concrete example, imagine you want
+to wait for \s-1STDIN\s0 to become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher
+for that:
+.PP
+.Vb 5
+\& static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
+\& {
+\& ev_io_stop (w);
+\& ev_break (loop, EVBREAK_ALL);
+\& }
+\&
+\& struct ev_loop *loop = ev_default_loop (0);
+\&
+\& ev_io stdin_watcher;
+\&
+\& ev_init (&stdin_watcher, my_cb);
+\& ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
+\& ev_io_start (loop, &stdin_watcher);
+\&
+\& ev_run (loop, 0);
+.Ve
+.PP
+As you can see, you are responsible for allocating the memory for your
+watcher structures (and it is \fIusually\fR a bad idea to do this on the
+stack).
+.PP
+Each watcher has an associated watcher structure (called \f(CW\*(C`struct ev_TYPE\*(C'\fR
+or simply \f(CW\*(C`ev_TYPE\*(C'\fR, as typedefs are provided for all watcher structs).
+.PP
+Each watcher structure must be initialised by a call to \f(CW\*(C`ev_init (watcher
+*, callback)\*(C'\fR, which expects a callback to be provided. This callback is
+invoked each time the event occurs (or, in the case of I/O watchers, each
+time the event loop detects that the file descriptor given is readable
+and/or writable).
+.PP
+Each watcher type further has its own \f(CW\*(C`ev_TYPE_set (watcher *, ...)\*(C'\fR
+macro to configure it, with arguments specific to the watcher type. There
+is also a macro to combine initialisation and setting in one call: \f(CW\*(C`ev_TYPE_init (watcher *, callback, ...)\*(C'\fR.
+.PP
+To make the watcher actually watch out for events, you have to start it
+with a watcher-specific start function (\f(CW\*(C`ev_TYPE_start (loop, watcher
+*)\*(C'\fR), and you can stop watching for events at any time by calling the
+corresponding stop function (\f(CW\*(C`ev_TYPE_stop (loop, watcher *)\*(C'\fR.
+.PP
+As long as your watcher is active (has been started but not stopped) you
+must not touch the values stored in it except when explicitly documented
+otherwise. Most specifically you must never reinitialise it or call its
+\&\f(CW\*(C`ev_TYPE_set\*(C'\fR macro.
+.PP
+Each and every callback receives the event loop pointer as first, the
+registered watcher structure as second, and a bitset of received events as
+third argument.
+.PP
+The received events usually include a single bit per event type received
+(you can receive multiple events at the same time). The possible bit masks
+are:
+.ie n .IP """EV_READ""" 4
+.el .IP "\f(CWEV_READ\fR" 4
+.IX Item "EV_READ"
+.PD 0
+.ie n .IP """EV_WRITE""" 4
+.el .IP "\f(CWEV_WRITE\fR" 4
+.IX Item "EV_WRITE"
+.PD
+The file descriptor in the \f(CW\*(C`ev_io\*(C'\fR watcher has become readable and/or
+writable.
+.ie n .IP """EV_TIMER""" 4
+.el .IP "\f(CWEV_TIMER\fR" 4
+.IX Item "EV_TIMER"
+The \f(CW\*(C`ev_timer\*(C'\fR watcher has timed out.
+.ie n .IP """EV_PERIODIC""" 4
+.el .IP "\f(CWEV_PERIODIC\fR" 4
+.IX Item "EV_PERIODIC"
+The \f(CW\*(C`ev_periodic\*(C'\fR watcher has timed out.
+.ie n .IP """EV_SIGNAL""" 4
+.el .IP "\f(CWEV_SIGNAL\fR" 4
+.IX Item "EV_SIGNAL"
+The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread.
+.ie n .IP """EV_CHILD""" 4
+.el .IP "\f(CWEV_CHILD\fR" 4
+.IX Item "EV_CHILD"
+The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change.
+.ie n .IP """EV_STAT""" 4
+.el .IP "\f(CWEV_STAT\fR" 4
+.IX Item "EV_STAT"
+The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow.
+.ie n .IP """EV_IDLE""" 4
+.el .IP "\f(CWEV_IDLE\fR" 4
+.IX Item "EV_IDLE"
+The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do.
+.ie n .IP """EV_PREPARE""" 4
+.el .IP "\f(CWEV_PREPARE\fR" 4
+.IX Item "EV_PREPARE"
+.PD 0
+.ie n .IP """EV_CHECK""" 4
+.el .IP "\f(CWEV_CHECK\fR" 4
+.IX Item "EV_CHECK"
+.PD
+All \f(CW\*(C`ev_prepare\*(C'\fR watchers are invoked just \fIbefore\fR \f(CW\*(C`ev_run\*(C'\fR starts to
+gather new events, and all \f(CW\*(C`ev_check\*(C'\fR watchers are queued (not invoked)
+just after \f(CW\*(C`ev_run\*(C'\fR has gathered them, but before it queues any callbacks
+for any received events. That means \f(CW\*(C`ev_prepare\*(C'\fR watchers are the last
+watchers invoked before the event loop sleeps or polls for new events, and
+\&\f(CW\*(C`ev_check\*(C'\fR watchers will be invoked before any other watchers of the same
+or lower priority within an event loop iteration.
+.Sp
+Callbacks of both watcher types can start and stop as many watchers as
+they want, and all of them will be taken into account (for example, a
+\&\f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep \f(CW\*(C`ev_run\*(C'\fR from
+blocking).
+.ie n .IP """EV_EMBED""" 4
+.el .IP "\f(CWEV_EMBED\fR" 4
+.IX Item "EV_EMBED"
+The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention.
+.ie n .IP """EV_FORK""" 4
+.el .IP "\f(CWEV_FORK\fR" 4
+.IX Item "EV_FORK"
+The event loop has been resumed in the child process after fork (see
+\&\f(CW\*(C`ev_fork\*(C'\fR).
+.ie n .IP """EV_CLEANUP""" 4
+.el .IP "\f(CWEV_CLEANUP\fR" 4
+.IX Item "EV_CLEANUP"
+The event loop is about to be destroyed (see \f(CW\*(C`ev_cleanup\*(C'\fR).
+.ie n .IP """EV_ASYNC""" 4
+.el .IP "\f(CWEV_ASYNC\fR" 4
+.IX Item "EV_ASYNC"
+The given async watcher has been asynchronously notified (see \f(CW\*(C`ev_async\*(C'\fR).
+.ie n .IP """EV_CUSTOM""" 4
+.el .IP "\f(CWEV_CUSTOM\fR" 4
+.IX Item "EV_CUSTOM"
+Not ever sent (or otherwise used) by libev itself, but can be freely used
+by libev users to signal watchers (e.g. via \f(CW\*(C`ev_feed_event\*(C'\fR).
+.ie n .IP """EV_ERROR""" 4
+.el .IP "\f(CWEV_ERROR\fR" 4
+.IX Item "EV_ERROR"
+An unspecified error has occurred, the watcher has been stopped. This might
+happen because the watcher could not be properly started because libev
+ran out of memory, a file descriptor was found to be closed or any other
+problem. Libev considers these application bugs.
+.Sp
+You best act on it by reporting the problem and somehow coping with the
+watcher being stopped. Note that well-written programs should not receive
+an error ever, so when your watcher receives it, this usually indicates a
+bug in your program.
+.Sp
+Libev will usually signal a few \*(L"dummy\*(R" events together with an error, for
+example it might indicate that a fd is readable or writable, and if your
+callbacks is well-written it can just attempt the operation and cope with
+the error from \fBread()\fR or \fBwrite()\fR. This will not work in multi-threaded
+programs, though, as the fd could already be closed and reused for another
+thing, so beware.
+.SS "\s-1GENERIC WATCHER FUNCTIONS\s0"
+.IX Subsection "GENERIC WATCHER FUNCTIONS"
+.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4
+.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4
+.IX Item "ev_init (ev_TYPE *watcher, callback)"
+This macro initialises the generic portion of a watcher. The contents
+of the watcher object can be arbitrary (so \f(CW\*(C`malloc\*(C'\fR will do). Only
+the generic parts of the watcher are initialised, you \fIneed\fR to call
+the type-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR macro afterwards to initialise the
+type-specific parts. For each type there is also a \f(CW\*(C`ev_TYPE_init\*(C'\fR macro
+which rolls both calls into one.
+.Sp
+You can reinitialise a watcher at any time as long as it has been stopped
+(or never started) and there are no pending events outstanding.
+.Sp
+The callback is always of type \f(CW\*(C`void (*)(struct ev_loop *loop, ev_TYPE *watcher,
+int revents)\*(C'\fR.
+.Sp
+Example: Initialise an \f(CW\*(C`ev_io\*(C'\fR watcher in two steps.
+.Sp
+.Vb 3
+\& ev_io w;
+\& ev_init (&w, my_cb);
+\& ev_io_set (&w, STDIN_FILENO, EV_READ);
+.Ve
+.ie n .IP """ev_TYPE_set"" (ev_TYPE *watcher, [args])" 4
+.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *watcher, [args])" 4
+.IX Item "ev_TYPE_set (ev_TYPE *watcher, [args])"
+This macro initialises the type-specific parts of a watcher. You need to
+call \f(CW\*(C`ev_init\*(C'\fR at least once before you call this macro, but you can
+call \f(CW\*(C`ev_TYPE_set\*(C'\fR any number of times. You must not, however, call this
+macro on a watcher that is active (it can be pending, however, which is a
+difference to the \f(CW\*(C`ev_init\*(C'\fR macro).
+.Sp
+Although some watcher types do not have type-specific arguments
+(e.g. \f(CW\*(C`ev_prepare\*(C'\fR) you still need to call its \f(CW\*(C`set\*(C'\fR macro.
+.Sp
+See \f(CW\*(C`ev_init\*(C'\fR, above, for an example.
+.ie n .IP """ev_TYPE_init"" (ev_TYPE *watcher, callback, [args])" 4
+.el .IP "\f(CWev_TYPE_init\fR (ev_TYPE *watcher, callback, [args])" 4
+.IX Item "ev_TYPE_init (ev_TYPE *watcher, callback, [args])"
+This convenience macro rolls both \f(CW\*(C`ev_init\*(C'\fR and \f(CW\*(C`ev_TYPE_set\*(C'\fR macro
+calls into a single call. This is the most convenient method to initialise
+a watcher. The same limitations apply, of course.
+.Sp
+Example: Initialise and set an \f(CW\*(C`ev_io\*(C'\fR watcher in one step.
+.Sp
+.Vb 1
+\& ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);
+.Ve
+.ie n .IP """ev_TYPE_start"" (loop, ev_TYPE *watcher)" 4
+.el .IP "\f(CWev_TYPE_start\fR (loop, ev_TYPE *watcher)" 4
+.IX Item "ev_TYPE_start (loop, ev_TYPE *watcher)"
+Starts (activates) the given watcher. Only active watchers will receive
+events. If the watcher is already active nothing will happen.
+.Sp
+Example: Start the \f(CW\*(C`ev_io\*(C'\fR watcher that is being abused as example in this
+whole section.
+.Sp
+.Vb 1
+\& ev_io_start (EV_DEFAULT_UC, &w);
+.Ve
+.ie n .IP """ev_TYPE_stop"" (loop, ev_TYPE *watcher)" 4
+.el .IP "\f(CWev_TYPE_stop\fR (loop, ev_TYPE *watcher)" 4
+.IX Item "ev_TYPE_stop (loop, ev_TYPE *watcher)"
+Stops the given watcher if active, and clears the pending status (whether
+the watcher was active or not).
+.Sp
+It is possible that stopped watchers are pending \- for example,
+non-repeating timers are being stopped when they become pending \- but
+calling \f(CW\*(C`ev_TYPE_stop\*(C'\fR ensures that the watcher is neither active nor
+pending. If you want to free or reuse the memory used by the watcher it is
+therefore a good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function.
+.IP "bool ev_is_active (ev_TYPE *watcher)" 4
+.IX Item "bool ev_is_active (ev_TYPE *watcher)"
+Returns a true value iff the watcher is active (i.e. it has been started
+and not yet been stopped). As long as a watcher is active you must not modify
+it.
+.IP "bool ev_is_pending (ev_TYPE *watcher)" 4
+.IX Item "bool ev_is_pending (ev_TYPE *watcher)"
+Returns a true value iff the watcher is pending, (i.e. it has outstanding
+events but its callback has not yet been invoked). As long as a watcher
+is pending (but not active) you must not call an init function on it (but
+\&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must
+make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR
+it).
+.IP "callback ev_cb (ev_TYPE *watcher)" 4
+.IX Item "callback ev_cb (ev_TYPE *watcher)"
+Returns the callback currently set on the watcher.
+.IP "ev_set_cb (ev_TYPE *watcher, callback)" 4
+.IX Item "ev_set_cb (ev_TYPE *watcher, callback)"
+Change the callback. You can change the callback at virtually any time
+(modulo threads).
+.IP "ev_set_priority (ev_TYPE *watcher, int priority)" 4
+.IX Item "ev_set_priority (ev_TYPE *watcher, int priority)"
+.PD 0
+.IP "int ev_priority (ev_TYPE *watcher)" 4
+.IX Item "int ev_priority (ev_TYPE *watcher)"
+.PD
+Set and query the priority of the watcher. The priority is a small
+integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR
+(default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked
+before watchers with lower priority, but priority will not keep watchers
+from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers).
+.Sp
+If you need to suppress invocation when higher priority events are pending
+you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality.
+.Sp
+You \fImust not\fR change the priority of a watcher as long as it is active or
+pending.
+.Sp
+Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is
+fine, as long as you do not mind that the priority value you query might
+or might not have been clamped to the valid range.
+.Sp
+The default priority used by watchers when no priority has been set is
+always \f(CW0\fR, which is supposed to not be too high and not be too low :).
+.Sp
+See \*(L"\s-1WATCHER PRIORITY MODELS\*(R"\s0, below, for a more thorough treatment of
+priorities.
+.IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4
+.IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)"
+Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither
+\&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback
+can deal with that fact, as both are simply passed through to the
+callback.
+.IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4
+.IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)"
+If the watcher is pending, this function clears its pending status and
+returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the
+watcher isn't pending it does nothing and returns \f(CW0\fR.
+.Sp
+Sometimes it can be useful to \*(L"poll\*(R" a watcher instead of waiting for its
+callback to be invoked, which can be accomplished with this function.
+.IP "ev_feed_event (loop, ev_TYPE *watcher, int revents)" 4
+.IX Item "ev_feed_event (loop, ev_TYPE *watcher, int revents)"
+Feeds the given event set into the event loop, as if the specified event
+had happened for the specified watcher (which must be a pointer to an
+initialised but not necessarily started event watcher). Obviously you must
+not free the watcher as long as it has pending events.
+.Sp
+Stopping the watcher, letting libev invoke it, or calling
+\&\f(CW\*(C`ev_clear_pending\*(C'\fR will clear the pending event, even if the watcher was
+not started in the first place.
+.Sp
+See also \f(CW\*(C`ev_feed_fd_event\*(C'\fR and \f(CW\*(C`ev_feed_signal_event\*(C'\fR for related
+functions that do not need a watcher.
+.PP
+See also the \*(L"\s-1ASSOCIATING CUSTOM DATA WITH A WATCHER\*(R"\s0 and \*(L"\s-1BUILDING YOUR
+OWN COMPOSITE WATCHERS\*(R"\s0 idioms.
+.SS "\s-1WATCHER STATES\s0"
+.IX Subsection "WATCHER STATES"
+There are various watcher states mentioned throughout this manual \-
+active, pending and so on. In this section these states and the rules to
+transition between them will be described in more detail \- and while these
+rules might look complicated, they usually do \*(L"the right thing\*(R".
+.IP "initialised" 4
+.IX Item "initialised"
+Before a watcher can be registered with the event loop it has to be
+initialised. This can be done with a call to \f(CW\*(C`ev_TYPE_init\*(C'\fR, or calls to
+\&\f(CW\*(C`ev_init\*(C'\fR followed by the watcher-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR function.
+.Sp
+In this state it is simply some block of memory that is suitable for
+use in an event loop. It can be moved around, freed, reused etc. at
+will \- as long as you either keep the memory contents intact, or call
+\&\f(CW\*(C`ev_TYPE_init\*(C'\fR again.
+.IP "started/running/active" 4
+.IX Item "started/running/active"
+Once a watcher has been started with a call to \f(CW\*(C`ev_TYPE_start\*(C'\fR it becomes
+property of the event loop, and is actively waiting for events. While in
+this state it cannot be accessed (except in a few documented ways), moved,
+freed or anything else \- the only legal thing is to keep a pointer to it,
+and call libev functions on it that are documented to work on active watchers.
+.IP "pending" 4
+.IX Item "pending"
+If a watcher is active and libev determines that an event it is interested
+in has occurred (such as a timer expiring), it will become pending. It will
+stay in this pending state until either it is stopped or its callback is
+about to be invoked, so it is not normally pending inside the watcher
+callback.
+.Sp
+The watcher might or might not be active while it is pending (for example,
+an expired non-repeating timer can be pending but no longer active). If it
+is stopped, it can be freely accessed (e.g. by calling \f(CW\*(C`ev_TYPE_set\*(C'\fR),
+but it is still property of the event loop at this time, so cannot be
+moved, freed or reused. And if it is active the rules described in the
+previous item still apply.
+.Sp
+It is also possible to feed an event on a watcher that is not active (e.g.
+via \f(CW\*(C`ev_feed_event\*(C'\fR), in which case it becomes pending without being
+active.
+.IP "stopped" 4
+.IX Item "stopped"
+A watcher can be stopped implicitly by libev (in which case it might still
+be pending), or explicitly by calling its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. The
+latter will clear any pending state the watcher might be in, regardless
+of whether it was active or not, so stopping a watcher explicitly before
+freeing it is often a good idea.
+.Sp
+While stopped (and not pending) the watcher is essentially in the
+initialised state, that is, it can be reused, moved, modified in any way
+you wish (but when you trash the memory block, you need to \f(CW\*(C`ev_TYPE_init\*(C'\fR
+it again).
+.SS "\s-1WATCHER PRIORITY MODELS\s0"
+.IX Subsection "WATCHER PRIORITY MODELS"
+Many event loops support \fIwatcher priorities\fR, which are usually small
+integers that influence the ordering of event callback invocation
+between watchers in some way, all else being equal.
+.PP
+In libev, watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its
+description for the more technical details such as the actual priority
+range.
+.PP
+There are two common ways how these these priorities are being interpreted
+by event loops:
+.PP
+In the more common lock-out model, higher priorities \*(L"lock out\*(R" invocation
+of lower priority watchers, which means as long as higher priority
+watchers receive events, lower priority watchers are not being invoked.
+.PP
+The less common only-for-ordering model uses priorities solely to order
+callback invocation within a single event loop iteration: Higher priority
+watchers are invoked before lower priority ones, but they all get invoked
+before polling for new events.
+.PP
+Libev uses the second (only-for-ordering) model for all its watchers
+except for idle watchers (which use the lock-out model).
+.PP
+The rationale behind this is that implementing the lock-out model for
+watchers is not well supported by most kernel interfaces, and most event
+libraries will just poll for the same events again and again as long as
+their callbacks have not been executed, which is very inefficient in the
+common case of one high-priority watcher locking out a mass of lower
+priority ones.
+.PP
+Static (ordering) priorities are most useful when you have two or more
+watchers handling the same resource: a typical usage example is having an
+\&\f(CW\*(C`ev_io\*(C'\fR watcher to receive data, and an associated \f(CW\*(C`ev_timer\*(C'\fR to handle
+timeouts. Under load, data might be received while the program handles
+other jobs, but since timers normally get invoked first, the timeout
+handler will be executed before checking for data. In that case, giving
+the timer a lower priority than the I/O watcher ensures that I/O will be
+handled first even under adverse conditions (which is usually, but not
+always, what you want).
+.PP
+Since idle watchers use the \*(L"lock-out\*(R" model, meaning that idle watchers
+will only be executed when no same or higher priority watchers have
+received events, they can be used to implement the \*(L"lock-out\*(R" model when
+required.
+.PP
+For example, to emulate how many other event libraries handle priorities,
+you can associate an \f(CW\*(C`ev_idle\*(C'\fR watcher to each such watcher, and in
+the normal watcher callback, you just start the idle watcher. The real
+processing is done in the idle watcher callback. This causes libev to
+continuously poll and process kernel event data for the watcher, but when
+the lock-out case is known to be rare (which in turn is rare :), this is
+workable.
+.PP
+Usually, however, the lock-out model implemented that way will perform
+miserably under the type of load it was designed to handle. In that case,
+it might be preferable to stop the real watcher before starting the
+idle watcher, so the kernel will not have to process the event in case
+the actual processing will be delayed for considerable time.
+.PP
+Here is an example of an I/O watcher that should run at a strictly lower
+priority than the default, and which should only process data when no
+other events are pending:
+.PP
+.Vb 2
+\& ev_idle idle; // actual processing watcher
+\& ev_io io; // actual event watcher
+\&
+\& static void
+\& io_cb (EV_P_ ev_io *w, int revents)
+\& {
+\& // stop the I/O watcher, we received the event, but
+\& // are not yet ready to handle it.
+\& ev_io_stop (EV_A_ w);
+\&
+\& // start the idle watcher to handle the actual event.
+\& // it will not be executed as long as other watchers
+\& // with the default priority are receiving events.
+\& ev_idle_start (EV_A_ &idle);
+\& }
+\&
+\& static void
+\& idle_cb (EV_P_ ev_idle *w, int revents)
+\& {
+\& // actual processing
+\& read (STDIN_FILENO, ...);
+\&
+\& // have to start the I/O watcher again, as
+\& // we have handled the event
+\& ev_io_start (EV_P_ &io);
+\& }
+\&
+\& // initialisation
+\& ev_idle_init (&idle, idle_cb);
+\& ev_io_init (&io, io_cb, STDIN_FILENO, EV_READ);
+\& ev_io_start (EV_DEFAULT_ &io);
+.Ve
+.PP
+In the \*(L"real\*(R" world, it might also be beneficial to start a timer, so that
+low-priority connections can not be locked out forever under load. This
+enables your program to keep a lower latency for important connections
+during short periods of high load, while not completely locking out less
+important ones.
+.SH "WATCHER TYPES"
+.IX Header "WATCHER TYPES"
+This section describes each watcher in detail, but will not repeat
+information given in the last section. Any initialisation/set macros,
+functions and members specific to the watcher type are explained.
+.PP
+Most members are additionally marked with either \fI[read\-only]\fR, meaning
+that, while the watcher is active, you can look at the member and expect
+some sensible content, but you must not modify it (you can modify it while
+the watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
+means you can expect it to have some sensible content while the watcher is
+active, but you can also modify it (within the same thread as the event
+loop, i.e. without creating data races). Modifying it may not do something
+sensible or take immediate effect (or do anything at all), but libev will
+not crash or malfunction in any way.
+.PP
+In any case, the documentation for each member will explain what the
+effects are, and if there are any additional access restrictions.
+.ie n .SS """ev_io"" \- is this file descriptor readable or writable?"
+.el .SS "\f(CWev_io\fP \- is this file descriptor readable or writable?"
+.IX Subsection "ev_io - is this file descriptor readable or writable?"
+I/O watchers check whether a file descriptor is readable or writable
+in each iteration of the event loop, or, more precisely, when reading
+would not block the process and writing would at least be able to write
+some data. This behaviour is called level-triggering because you keep
+receiving events as long as the condition persists. Remember you can stop
+the watcher if you don't want to act on the event and neither want to
+receive future events.
+.PP
+In general you can register as many read and/or write event watchers per
+fd as you want (as long as you don't confuse yourself). Setting all file
+descriptors to non-blocking mode is also usually a good idea (but not
+required if you know what you are doing).
+.PP
+Another thing you have to watch out for is that it is quite easy to
+receive \*(L"spurious\*(R" readiness notifications, that is, your callback might
+be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block
+because there is no data. It is very easy to get into this situation even
+with a relatively standard program structure. Thus it is best to always
+use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning \f(CW\*(C`EAGAIN\*(C'\fR is far
+preferable to a program hanging until some data arrives.
+.PP
+If you cannot run the fd in non-blocking mode (for example you should
+not play around with an Xlib connection), then you have to separately
+re-test whether a file descriptor is really ready with a known-to-be good
+interface such as poll (fortunately in the case of Xlib, it already does
+this on its own, so its quite safe to use). Some people additionally
+use \f(CW\*(C`SIGALRM\*(C'\fR and an interval timer, just to be sure you won't block
+indefinitely.
+.PP
+But really, best use non-blocking mode.
+.PP
+\fIThe special problem of disappearing file descriptors\fR
+.IX Subsection "The special problem of disappearing file descriptors"
+.PP
+Some backends (e.g. kqueue, epoll, linuxaio) need to be told about closing
+a file descriptor (either due to calling \f(CW\*(C`close\*(C'\fR explicitly or any other
+means, such as \f(CW\*(C`dup2\*(C'\fR). The reason is that you register interest in some
+file descriptor, but when it goes away, the operating system will silently
+drop this interest. If another file descriptor with the same number then
+is registered with libev, there is no efficient way to see that this is,
+in fact, a different file descriptor.
+.PP
+To avoid having to explicitly tell libev about such cases, libev follows
+the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev
+will assume that this is potentially a new file descriptor, otherwise
+it is assumed that the file descriptor stays the same. That means that
+you \fIhave\fR to call \f(CW\*(C`ev_io_set\*(C'\fR (or \f(CW\*(C`ev_io_init\*(C'\fR) when you change the
+descriptor even if the file descriptor number itself did not change.
+.PP
+This is how one would do it normally anyway, the important point is that
+the libev application should not optimise around libev but should leave
+optimisations to libev.
+.PP
+\fIThe special problem of dup'ed file descriptors\fR
+.IX Subsection "The special problem of dup'ed file descriptors"
+.PP
+Some backends (e.g. epoll), cannot register events for file descriptors,
+but only events for the underlying file descriptions. That means when you
+have \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors or weirder constellations, and register
+events for them, only one file descriptor might actually receive events.
+.PP
+There is no workaround possible except not registering events
+for potentially \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors, or to resort to
+\&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
+.PP
+\fIThe special problem of files\fR
+.IX Subsection "The special problem of files"
+.PP
+Many people try to use \f(CW\*(C`select\*(C'\fR (or libev) on file descriptors
+representing files, and expect it to become ready when their program
+doesn't block on disk accesses (which can take a long time on their own).
+.PP
+However, this cannot ever work in the \*(L"expected\*(R" way \- you get a readiness
+notification as soon as the kernel knows whether and how much data is
+there, and in the case of open files, that's always the case, so you
+always get a readiness notification instantly, and your read (or possibly
+write) will still block on the disk I/O.
+.PP
+Another way to view it is that in the case of sockets, pipes, character
+devices and so on, there is another party (the sender) that delivers data
+on its own, but in the case of files, there is no such thing: the disk
+will not send data on its own, simply because it doesn't know what you
+wish to read \- you would first have to request some data.
+.PP
+Since files are typically not-so-well supported by advanced notification
+mechanism, libev tries hard to emulate \s-1POSIX\s0 behaviour with respect
+to files, even though you should not use it. The reason for this is
+convenience: sometimes you want to watch \s-1STDIN\s0 or \s-1STDOUT,\s0 which is
+usually a tty, often a pipe, but also sometimes files or special devices
+(for example, \f(CW\*(C`epoll\*(C'\fR on Linux works with \fI/dev/random\fR but not with
+\&\fI/dev/urandom\fR), and even though the file might better be served with
+asynchronous I/O instead of with non-blocking I/O, it is still useful when
+it \*(L"just works\*(R" instead of freezing.
+.PP
+So avoid file descriptors pointing to files when you know it (e.g. use
+libeio), but use them when it is convenient, e.g. for \s-1STDIN/STDOUT,\s0 or
+when you rarely read from a file instead of from a socket, and want to
+reuse the same code path.
+.PP
+\fIThe special problem of fork\fR
+.IX Subsection "The special problem of fork"
+.PP
+Some backends (epoll, kqueue, linuxaio, iouring) do not support \f(CW\*(C`fork ()\*(C'\fR
+at all or exhibit useless behaviour. Libev fully supports fork, but needs
+to be told about it in the child if you want to continue to use it in the
+child.
+.PP
+To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork
+()\*(C'\fR after a fork in the child, enable \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR, or resort to
+\&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
+.PP
+\fIThe special problem of \s-1SIGPIPE\s0\fR
+.IX Subsection "The special problem of SIGPIPE"
+.PP
+While not really specific to libev, it is easy to forget about \f(CW\*(C`SIGPIPE\*(C'\fR:
+when writing to a pipe whose other end has been closed, your program gets
+sent a \s-1SIGPIPE,\s0 which, by default, aborts your program. For most programs
+this is sensible behaviour, for daemons, this is usually undesirable.
+.PP
+So when you encounter spurious, unexplained daemon exits, make sure you
+ignore \s-1SIGPIPE\s0 (and maybe make sure you log the exit status of your daemon
+somewhere, as that would have given you a big clue).
+.PP
+\fIThe special problem of \f(BIaccept()\fIing when you can't\fR
+.IX Subsection "The special problem of accept()ing when you can't"
+.PP
+Many implementations of the \s-1POSIX\s0 \f(CW\*(C`accept\*(C'\fR function (for example,
+found in post\-2004 Linux) have the peculiar behaviour of not removing a
+connection from the pending queue in all error cases.
+.PP
+For example, larger servers often run out of file descriptors (because
+of resource limits), causing \f(CW\*(C`accept\*(C'\fR to fail with \f(CW\*(C`ENFILE\*(C'\fR but not
+rejecting the connection, leading to libev signalling readiness on
+the next iteration again (the connection still exists after all), and
+typically causing the program to loop at 100% \s-1CPU\s0 usage.
+.PP
+Unfortunately, the set of errors that cause this issue differs between
+operating systems, there is usually little the app can do to remedy the
+situation, and no known thread-safe method of removing the connection to
+cope with overload is known (to me).
+.PP
+One of the easiest ways to handle this situation is to just ignore it
+\&\- when the program encounters an overload, it will just loop until the
+situation is over. While this is a form of busy waiting, no \s-1OS\s0 offers an
+event-based way to handle this situation, so it's the best one can do.
+.PP
+A better way to handle the situation is to log any errors other than
+\&\f(CW\*(C`EAGAIN\*(C'\fR and \f(CW\*(C`EWOULDBLOCK\*(C'\fR, making sure not to flood the log with such
+messages, and continue as usual, which at least gives the user an idea of
+what could be wrong (\*(L"raise the ulimit!\*(R"). For extra points one could stop
+the \f(CW\*(C`ev_io\*(C'\fR watcher on the listening fd \*(L"for a while\*(R", which reduces \s-1CPU\s0
+usage.
+.PP
+If your program is single-threaded, then you could also keep a dummy file
+descriptor for overload situations (e.g. by opening \fI/dev/null\fR), and
+when you run into \f(CW\*(C`ENFILE\*(C'\fR or \f(CW\*(C`EMFILE\*(C'\fR, close it, run \f(CW\*(C`accept\*(C'\fR,
+close that fd, and create a new dummy fd. This will gracefully refuse
+clients under typical overload conditions.
+.PP
+The last way to handle it is to simply log the error and \f(CW\*(C`exit\*(C'\fR, as
+is often done with \f(CW\*(C`malloc\*(C'\fR failures, but this results in an easy
+opportunity for a DoS attack.
+.PP
+\fIWatcher-Specific Functions\fR
+.IX Subsection "Watcher-Specific Functions"
+.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
+.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
+.PD 0
+.IP "ev_io_set (ev_io *, int fd, int events)" 4
+.IX Item "ev_io_set (ev_io *, int fd, int events)"
+.PD
+Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to
+receive events for and \f(CW\*(C`events\*(C'\fR is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR, both
+\&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR or \f(CW0\fR, to express the desire to receive the given
+events.
+.Sp
+Note that setting the \f(CW\*(C`events\*(C'\fR to \f(CW0\fR and starting the watcher is
+supported, but not specially optimized \- if your program sometimes happens
+to generate this combination this is fine, but if it is easy to avoid
+starting an io watcher watching for no events you should do so.
+.IP "ev_io_modify (ev_io *, int events)" 4
+.IX Item "ev_io_modify (ev_io *, int events)"
+Similar to \f(CW\*(C`ev_io_set\*(C'\fR, but only changes the requested events. Using this
+might be faster with some backends, as libev can assume that the \f(CW\*(C`fd\*(C'\fR
+still refers to the same underlying file description, something it cannot
+do when using \f(CW\*(C`ev_io_set\*(C'\fR.
+.IP "int fd [no\-modify]" 4
+.IX Item "int fd [no-modify]"
+The file descriptor being watched. While it can be read at any time, you
+must not modify this member even when the watcher is stopped \- always use
+\&\f(CW\*(C`ev_io_set\*(C'\fR for that.
+.IP "int events [no\-modify]" 4
+.IX Item "int events [no-modify]"
+The set of events the fd is being watched for, among other flags. Remember
+that this is a bit set \- to test for \f(CW\*(C`EV_READ\*(C'\fR, use \f(CW\*(C`w\->events &
+EV_READ\*(C'\fR, and similarly for \f(CW\*(C`EV_WRITE\*(C'\fR.
+.Sp
+As with \f(CW\*(C`fd\*(C'\fR, you must not modify this member even when the watcher is
+stopped, always use \f(CW\*(C`ev_io_set\*(C'\fR or \f(CW\*(C`ev_io_modify\*(C'\fR for that.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well
+readable, but only once. Since it is likely line-buffered, you could
+attempt to read a whole line in the callback.
+.PP
+.Vb 6
+\& static void
+\& stdin_readable_cb (struct ev_loop *loop, ev_io *w, int revents)
+\& {
+\& ev_io_stop (loop, w);
+\& .. read from stdin here (or from w\->fd) and handle any I/O errors
+\& }
+\&
+\& ...
+\& struct ev_loop *loop = ev_default_init (0);
+\& ev_io stdin_readable;
+\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
+\& ev_io_start (loop, &stdin_readable);
+\& ev_run (loop, 0);
+.Ve
+.ie n .SS """ev_timer"" \- relative and optionally repeating timeouts"
+.el .SS "\f(CWev_timer\fP \- relative and optionally repeating timeouts"
+.IX Subsection "ev_timer - relative and optionally repeating timeouts"
+Timer watchers are simple relative timers that generate an event after a
+given time, and optionally repeating in regular intervals after that.
+.PP
+The timers are based on real time, that is, if you register an event that
+times out after an hour and you reset your system clock to January last
+year, it will still time out after (roughly) one hour. \*(L"Roughly\*(R" because
+detecting time jumps is hard, and some inaccuracies are unavoidable (the
+monotonic clock option helps a lot here).
+.PP
+The callback is guaranteed to be invoked only \fIafter\fR its timeout has
+passed (not \fIat\fR, so on systems with very low-resolution clocks this
+might introduce a small delay, see \*(L"the special problem of being too
+early\*(R", below). If multiple timers become ready during the same loop
+iteration then the ones with earlier time-out values are invoked before
+ones of the same priority with later time-out values (but this is no
+longer true when a callback calls \f(CW\*(C`ev_run\*(C'\fR recursively).
+.PP
+\fIBe smart about timeouts\fR
+.IX Subsection "Be smart about timeouts"
+.PP
+Many real-world problems involve some kind of timeout, usually for error
+recovery. A typical example is an \s-1HTTP\s0 request \- if the other side hangs,
+you want to raise some error after a while.
+.PP
+What follows are some ways to handle this problem, from obvious and
+inefficient to smart and efficient.
+.PP
+In the following, a 60 second activity timeout is assumed \- a timeout that
+gets reset to 60 seconds each time there is activity (e.g. each time some
+data or other life sign was received).
+.IP "1. Use a timer and stop, reinitialise and start it on activity." 4
+.IX Item "1. Use a timer and stop, reinitialise and start it on activity."
+This is the most obvious, but not the most simple way: In the beginning,
+start the watcher:
+.Sp
+.Vb 2
+\& ev_timer_init (timer, callback, 60., 0.);
+\& ev_timer_start (loop, timer);
+.Ve
+.Sp
+Then, each time there is some activity, \f(CW\*(C`ev_timer_stop\*(C'\fR it, initialise it
+and start it again:
+.Sp
+.Vb 3
+\& ev_timer_stop (loop, timer);
+\& ev_timer_set (timer, 60., 0.);
+\& ev_timer_start (loop, timer);
+.Ve
+.Sp
+This is relatively simple to implement, but means that each time there is
+some activity, libev will first have to remove the timer from its internal
+data structure and then add it again. Libev tries to be fast, but it's
+still not a constant-time operation.
+.ie n .IP "2. Use a timer and re-start it with ""ev_timer_again"" inactivity." 4
+.el .IP "2. Use a timer and re-start it with \f(CWev_timer_again\fR inactivity." 4
+.IX Item "2. Use a timer and re-start it with ev_timer_again inactivity."
+This is the easiest way, and involves using \f(CW\*(C`ev_timer_again\*(C'\fR instead of
+\&\f(CW\*(C`ev_timer_start\*(C'\fR.
+.Sp
+To implement this, configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value
+of \f(CW60\fR and then call \f(CW\*(C`ev_timer_again\*(C'\fR at start and each time you
+successfully read or write some data. If you go into an idle state where
+you do not expect data to travel on the socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR
+the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will automatically restart it if need be.
+.Sp
+That means you can ignore both the \f(CW\*(C`ev_timer_start\*(C'\fR function and the
+\&\f(CW\*(C`after\*(C'\fR argument to \f(CW\*(C`ev_timer_set\*(C'\fR, and only ever use the \f(CW\*(C`repeat\*(C'\fR
+member and \f(CW\*(C`ev_timer_again\*(C'\fR.
+.Sp
+At start:
+.Sp
+.Vb 3
+\& ev_init (timer, callback);
+\& timer\->repeat = 60.;
+\& ev_timer_again (loop, timer);
+.Ve
+.Sp
+Each time there is some activity:
+.Sp
+.Vb 1
+\& ev_timer_again (loop, timer);
+.Ve
+.Sp
+It is even possible to change the time-out on the fly, regardless of
+whether the watcher is active or not:
+.Sp
+.Vb 2
+\& timer\->repeat = 30.;
+\& ev_timer_again (loop, timer);
+.Ve
+.Sp
+This is slightly more efficient then stopping/starting the timer each time
+you want to modify its timeout value, as libev does not have to completely
+remove and re-insert the timer from/into its internal data structure.
+.Sp
+It is, however, even simpler than the \*(L"obvious\*(R" way to do it.
+.IP "3. Let the timer time out, but then re-arm it as required." 4
+.IX Item "3. Let the timer time out, but then re-arm it as required."
+This method is more tricky, but usually most efficient: Most timeouts are
+relatively long compared to the intervals between other activity \- in
+our example, within 60 seconds, there are usually many I/O events with
+associated activity resets.
+.Sp
+In this case, it would be more efficient to leave the \f(CW\*(C`ev_timer\*(C'\fR alone,
+but remember the time of last activity, and check for a real timeout only
+within the callback:
+.Sp
+.Vb 3
+\& ev_tstamp timeout = 60.;
+\& ev_tstamp last_activity; // time of last activity
+\& ev_timer timer;
+\&
+\& static void
+\& callback (EV_P_ ev_timer *w, int revents)
+\& {
+\& // calculate when the timeout would happen
+\& ev_tstamp after = last_activity \- ev_now (EV_A) + timeout;
+\&
+\& // if negative, it means we the timeout already occurred
+\& if (after < 0.)
+\& {
+\& // timeout occurred, take action
+\& }
+\& else
+\& {
+\& // callback was invoked, but there was some recent
+\& // activity. simply restart the timer to time out
+\& // after "after" seconds, which is the earliest time
+\& // the timeout can occur.
+\& ev_timer_set (w, after, 0.);
+\& ev_timer_start (EV_A_ w);
+\& }
+\& }
+.Ve
+.Sp
+To summarise the callback: first calculate in how many seconds the
+timeout will occur (by calculating the absolute time when it would occur,
+\&\f(CW\*(C`last_activity + timeout\*(C'\fR, and subtracting the current time, \f(CW\*(C`ev_now
+(EV_A)\*(C'\fR from that).
+.Sp
+If this value is negative, then we are already past the timeout, i.e. we
+timed out, and need to do whatever is needed in this case.
+.Sp
+Otherwise, we now the earliest time at which the timeout would trigger,
+and simply start the timer with this timeout value.
+.Sp
+In other words, each time the callback is invoked it will check whether
+the timeout occurred. If not, it will simply reschedule itself to check
+again at the earliest time it could time out. Rinse. Repeat.
+.Sp
+This scheme causes more callback invocations (about one every 60 seconds
+minus half the average time between activity), but virtually no calls to
+libev to change the timeout.
+.Sp
+To start the machinery, simply initialise the watcher and set
+\&\f(CW\*(C`last_activity\*(C'\fR to the current time (meaning there was some activity just
+now), then call the callback, which will \*(L"do the right thing\*(R" and start
+the timer:
+.Sp
+.Vb 3
+\& last_activity = ev_now (EV_A);
+\& ev_init (&timer, callback);
+\& callback (EV_A_ &timer, 0);
+.Ve
+.Sp
+When there is some activity, simply store the current time in
+\&\f(CW\*(C`last_activity\*(C'\fR, no libev calls at all:
+.Sp
+.Vb 2
+\& if (activity detected)
+\& last_activity = ev_now (EV_A);
+.Ve
+.Sp
+When your timeout value changes, then the timeout can be changed by simply
+providing a new value, stopping the timer and calling the callback, which
+will again do the right thing (for example, time out immediately :).
+.Sp
+.Vb 3
+\& timeout = new_value;
+\& ev_timer_stop (EV_A_ &timer);
+\& callback (EV_A_ &timer, 0);
+.Ve
+.Sp
+This technique is slightly more complex, but in most cases where the
+time-out is unlikely to be triggered, much more efficient.
+.IP "4. Wee, just use a double-linked list for your timeouts." 4
+.IX Item "4. Wee, just use a double-linked list for your timeouts."
+If there is not one request, but many thousands (millions...), all
+employing some kind of timeout with the same timeout value, then one can
+do even better:
+.Sp
+When starting the timeout, calculate the timeout value and put the timeout
+at the \fIend\fR of the list.
+.Sp
+Then use an \f(CW\*(C`ev_timer\*(C'\fR to fire when the timeout at the \fIbeginning\fR of
+the list is expected to fire (for example, using the technique #3).
+.Sp
+When there is some activity, remove the timer from the list, recalculate
+the timeout, append it to the end of the list again, and make sure to
+update the \f(CW\*(C`ev_timer\*(C'\fR if it was taken from the beginning of the list.
+.Sp
+This way, one can manage an unlimited number of timeouts in O(1) time for
+starting, stopping and updating the timers, at the expense of a major
+complication, and having to use a constant timeout. The constant timeout
+ensures that the list stays sorted.
+.PP
+So which method the best?
+.PP
+Method #2 is a simple no-brain-required solution that is adequate in most
+situations. Method #3 requires a bit more thinking, but handles many cases
+better, and isn't very complicated either. In most case, choosing either
+one is fine, with #3 being better in typical situations.
+.PP
+Method #1 is almost always a bad idea, and buys you nothing. Method #4 is
+rather complicated, but extremely efficient, something that really pays
+off after the first million or so of active timers, i.e. it's usually
+overkill :)
+.PP
+\fIThe special problem of being too early\fR
+.IX Subsection "The special problem of being too early"
+.PP
+If you ask a timer to call your callback after three seconds, then
+you expect it to be invoked after three seconds \- but of course, this
+cannot be guaranteed to infinite precision. Less obviously, it cannot be
+guaranteed to any precision by libev \- imagine somebody suspending the
+process with a \s-1STOP\s0 signal for a few hours for example.
+.PP
+So, libev tries to invoke your callback as soon as possible \fIafter\fR the
+delay has occurred, but cannot guarantee this.
+.PP
+A less obvious failure mode is calling your callback too early: many event
+loops compare timestamps with a \*(L"elapsed delay >= requested delay\*(R", but
+this can cause your callback to be invoked much earlier than you would
+expect.
+.PP
+To see why, imagine a system with a clock that only offers full second
+resolution (think windows if you can't come up with a broken enough \s-1OS\s0
+yourself). If you schedule a one-second timer at the time 500.9, then the
+event loop will schedule your timeout to elapse at a system time of 500
+(500.9 truncated to the resolution) + 1, or 501.
+.PP
+If an event library looks at the timeout 0.1s later, it will see \*(L"501 >=
+501\*(R" and invoke the callback 0.1s after it was started, even though a
+one-second delay was requested \- this is being \*(L"too early\*(R", despite best
+intentions.
+.PP
+This is the reason why libev will never invoke the callback if the elapsed
+delay equals the requested delay, but only when the elapsed delay is
+larger than the requested delay. In the example above, libev would only invoke
+the callback at system time 502, or 1.1s after the timer was started.
+.PP
+So, while libev cannot guarantee that your callback will be invoked
+exactly when requested, it \fIcan\fR and \fIdoes\fR guarantee that the requested
+delay has actually elapsed, or in other words, it always errs on the \*(L"too
+late\*(R" side of things.
+.PP
+\fIThe special problem of time updates\fR
+.IX Subsection "The special problem of time updates"
+.PP
+Establishing the current time is a costly operation (it usually takes
+at least one system call): \s-1EV\s0 therefore updates its idea of the current
+time only before and after \f(CW\*(C`ev_run\*(C'\fR collects new events, which causes a
+growing difference between \f(CW\*(C`ev_now ()\*(C'\fR and \f(CW\*(C`ev_time ()\*(C'\fR when handling
+lots of events in one iteration.
+.PP
+The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR
+time. This is usually the right thing as this timestamp refers to the time
+of the event triggering whatever timeout you are modifying/starting. If
+you suspect event processing to be delayed and you \fIneed\fR to base the
+timeout on the current time, use something like the following to adjust
+for it:
+.PP
+.Vb 1
+\& ev_timer_set (&timer, after + (ev_time () \- ev_now ()), 0.);
+.Ve
+.PP
+If the event loop is suspended for a long time, you can also force an
+update of the time returned by \f(CW\*(C`ev_now ()\*(C'\fR by calling \f(CW\*(C`ev_now_update
+()\*(C'\fR, although that will push the event time of all outstanding events
+further into the future.
+.PP
+\fIThe special problem of unsynchronised clocks\fR
+.IX Subsection "The special problem of unsynchronised clocks"
+.PP
+Modern systems have a variety of clocks \- libev itself uses the normal
+\&\*(L"wall clock\*(R" clock and, if available, the monotonic clock (to avoid time
+jumps).
+.PP
+Neither of these clocks is synchronised with each other or any other clock
+on the system, so \f(CW\*(C`ev_time ()\*(C'\fR might return a considerably different time
+than \f(CW\*(C`gettimeofday ()\*(C'\fR or \f(CW\*(C`time ()\*(C'\fR. On a GNU/Linux system, for example,
+a call to \f(CW\*(C`gettimeofday\*(C'\fR might return a second count that is one higher
+than a directly following call to \f(CW\*(C`time\*(C'\fR.
+.PP
+The moral of this is to only compare libev-related timestamps with
+\&\f(CW\*(C`ev_time ()\*(C'\fR and \f(CW\*(C`ev_now ()\*(C'\fR, at least if you want better precision than
+a second or so.
+.PP
+One more problem arises due to this lack of synchronisation: if libev uses
+the system monotonic clock and you compare timestamps from \f(CW\*(C`ev_time\*(C'\fR
+or \f(CW\*(C`ev_now\*(C'\fR from when you started your timer and when your callback is
+invoked, you will find that sometimes the callback is a bit \*(L"early\*(R".
+.PP
+This is because \f(CW\*(C`ev_timer\*(C'\fRs work in real time, not wall clock time, so
+libev makes sure your callback is not invoked before the delay happened,
+\&\fImeasured according to the real time\fR, not the system clock.
+.PP
+If your timeouts are based on a physical timescale (e.g. \*(L"time out this
+connection after 100 seconds\*(R") then this shouldn't bother you as it is
+exactly the right behaviour.
+.PP
+If you want to compare wall clock/system timestamps to your timers, then
+you need to use \f(CW\*(C`ev_periodic\*(C'\fRs, as these are based on the wall clock
+time, where your comparisons will always generate correct results.
+.PP
+\fIThe special problems of suspended animation\fR
+.IX Subsection "The special problems of suspended animation"
+.PP
+When you leave the server world it is quite customary to hit machines that
+can suspend/hibernate \- what happens to the clocks during such a suspend?
+.PP
+Some quick tests made with a Linux 2.6.28 indicate that a suspend freezes
+all processes, while the clocks (\f(CW\*(C`times\*(C'\fR, \f(CW\*(C`CLOCK_MONOTONIC\*(C'\fR) continue
+to run until the system is suspended, but they will not advance while the
+system is suspended. That means, on resume, it will be as if the program
+was frozen for a few seconds, but the suspend time will not be counted
+towards \f(CW\*(C`ev_timer\*(C'\fR when a monotonic clock source is used. The real time
+clock advanced as expected, but if it is used as sole clocksource, then a
+long suspend would be detected as a time jump by libev, and timers would
+be adjusted accordingly.
+.PP
+I would not be surprised to see different behaviour in different between
+operating systems, \s-1OS\s0 versions or even different hardware.
+.PP
+The other form of suspend (job control, or sending a \s-1SIGSTOP\s0) will see a
+time jump in the monotonic clocks and the realtime clock. If the program
+is suspended for a very long time, and monotonic clock sources are in use,
+then you can expect \f(CW\*(C`ev_timer\*(C'\fRs to expire as the full suspension time
+will be counted towards the timers. When no monotonic clock source is in
+use, then libev will again assume a timejump and adjust accordingly.
+.PP
+It might be beneficial for this latter case to call \f(CW\*(C`ev_suspend\*(C'\fR
+and \f(CW\*(C`ev_resume\*(C'\fR in code that handles \f(CW\*(C`SIGTSTP\*(C'\fR, to at least get
+deterministic behaviour in this case (you can do nothing against
+\&\f(CW\*(C`SIGSTOP\*(C'\fR).
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4
+.IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)"
+.PD 0
+.IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4
+.IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)"
+.PD
+Configure the timer to trigger after \f(CW\*(C`after\*(C'\fR seconds (fractional and
+negative values are supported). If \f(CW\*(C`repeat\*(C'\fR is \f(CW0.\fR, then it will
+automatically be stopped once the timeout is reached. If it is positive,
+then the timer will automatically be configured to trigger again \f(CW\*(C`repeat\*(C'\fR
+seconds later, again, and again, until stopped manually.
+.Sp
+The timer itself will do a best-effort at avoiding drift, that is, if
+you configure a timer to trigger every 10 seconds, then it will normally
+trigger at exactly 10 second intervals. If, however, your program cannot
+keep up with the timer (because it takes longer than those 10 seconds to
+do stuff) the timer will not fire more than once per event loop iteration.
+.IP "ev_timer_again (loop, ev_timer *)" 4
+.IX Item "ev_timer_again (loop, ev_timer *)"
+This will act as if the timer timed out, and restarts it again if it is
+repeating. It basically works like calling \f(CW\*(C`ev_timer_stop\*(C'\fR, updating the
+timeout to the \f(CW\*(C`repeat\*(C'\fR value and calling \f(CW\*(C`ev_timer_start\*(C'\fR.
+.Sp
+The exact semantics are as in the following rules, all of which will be
+applied to the watcher:
+.RS 4
+.IP "If the timer is pending, the pending status is always cleared." 4
+.IX Item "If the timer is pending, the pending status is always cleared."
+.PD 0
+.IP "If the timer is started but non-repeating, stop it (as if it timed out, without invoking it)." 4
+.IX Item "If the timer is started but non-repeating, stop it (as if it timed out, without invoking it)."
+.ie n .IP "If the timer is repeating, make the ""repeat"" value the new timeout and start the timer, if necessary." 4
+.el .IP "If the timer is repeating, make the \f(CWrepeat\fR value the new timeout and start the timer, if necessary." 4
+.IX Item "If the timer is repeating, make the repeat value the new timeout and start the timer, if necessary."
+.RE
+.RS 4
+.PD
+.Sp
+This sounds a bit complicated, see \*(L"Be smart about timeouts\*(R", above, for a
+usage example.
+.RE
+.IP "ev_tstamp ev_timer_remaining (loop, ev_timer *)" 4
+.IX Item "ev_tstamp ev_timer_remaining (loop, ev_timer *)"
+Returns the remaining time until a timer fires. If the timer is active,
+then this time is relative to the current event loop time, otherwise it's
+the timeout value currently configured.
+.Sp
+That is, after an \f(CW\*(C`ev_timer_set (w, 5, 7)\*(C'\fR, \f(CW\*(C`ev_timer_remaining\*(C'\fR returns
+\&\f(CW5\fR. When the timer is started and one second passes, \f(CW\*(C`ev_timer_remaining\*(C'\fR
+will return \f(CW4\fR. When the timer expires and is restarted, it will return
+roughly \f(CW7\fR (likely slightly less as callback invocation takes some time,
+too), and so on.
+.IP "ev_tstamp repeat [read\-write]" 4
+.IX Item "ev_tstamp repeat [read-write]"
+The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out
+or \f(CW\*(C`ev_timer_again\*(C'\fR is called, and determines the next timeout (if any),
+which is also when any modifications are taken into account.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Create a timer that fires after 60 seconds.
+.PP
+.Vb 5
+\& static void
+\& one_minute_cb (struct ev_loop *loop, ev_timer *w, int revents)
+\& {
+\& .. one minute over, w is actually stopped right here
+\& }
+\&
+\& ev_timer mytimer;
+\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
+\& ev_timer_start (loop, &mytimer);
+.Ve
+.PP
+Example: Create a timeout timer that times out after 10 seconds of
+inactivity.
+.PP
+.Vb 5
+\& static void
+\& timeout_cb (struct ev_loop *loop, ev_timer *w, int revents)
+\& {
+\& .. ten seconds without any activity
+\& }
+\&
+\& ev_timer mytimer;
+\& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
+\& ev_timer_again (&mytimer); /* start timer */
+\& ev_run (loop, 0);
+\&
+\& // and in some piece of code that gets executed on any "activity":
+\& // reset the timeout to start ticking again at 10 seconds
+\& ev_timer_again (&mytimer);
+.Ve
+.ie n .SS """ev_periodic"" \- to cron or not to cron?"
+.el .SS "\f(CWev_periodic\fP \- to cron or not to cron?"
+.IX Subsection "ev_periodic - to cron or not to cron?"
+Periodic watchers are also timers of a kind, but they are very versatile
+(and unfortunately a bit complex).
+.PP
+Unlike \f(CW\*(C`ev_timer\*(C'\fR, periodic watchers are not based on real time (or
+relative time, the physical time that passes) but on wall clock time
+(absolute time, the thing you can read on your calendar or clock). The
+difference is that wall clock time can run faster or slower than real
+time, and time jumps are not uncommon (e.g. when you adjust your
+wrist-watch).
+.PP
+You can tell a periodic watcher to trigger after some specific point
+in time: for example, if you tell a periodic watcher to trigger \*(L"in 10
+seconds\*(R" (by specifying e.g. \f(CW\*(C`ev_now () + 10.\*(C'\fR, that is, an absolute time
+not a delay) and then reset your system clock to January of the previous
+year, then it will take a year or more to trigger the event (unlike an
+\&\f(CW\*(C`ev_timer\*(C'\fR, which would still trigger roughly 10 seconds after starting
+it, as it uses a relative timeout).
+.PP
+\&\f(CW\*(C`ev_periodic\*(C'\fR watchers can also be used to implement vastly more complex
+timers, such as triggering an event on each \*(L"midnight, local time\*(R", or
+other complicated rules. This cannot easily be done with \f(CW\*(C`ev_timer\*(C'\fR
+watchers, as those cannot react to time jumps.
+.PP
+As with timers, the callback is guaranteed to be invoked only when the
+point in time where it is supposed to trigger has passed. If multiple
+timers become ready during the same loop iteration then the ones with
+earlier time-out values are invoked before ones with later time-out values
+(but this is no longer true when a callback calls \f(CW\*(C`ev_run\*(C'\fR recursively).
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)" 4
+.IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)"
+.PD 0
+.IP "ev_periodic_set (ev_periodic *, ev_tstamp offset, ev_tstamp interval, reschedule_cb)" 4
+.IX Item "ev_periodic_set (ev_periodic *, ev_tstamp offset, ev_tstamp interval, reschedule_cb)"
+.PD
+Lots of arguments, let's sort it out... There are basically three modes of
+operation, and we will explain them from simplest to most complex:
+.RS 4
+.IP "\(bu" 4
+absolute timer (offset = absolute time, interval = 0, reschedule_cb = 0)
+.Sp
+In this configuration the watcher triggers an event after the wall clock
+time \f(CW\*(C`offset\*(C'\fR has passed. It will not repeat and will not adjust when a
+time jump occurs, that is, if it is to be run at January 1st 2011 then it
+will be stopped and invoked when the system clock reaches or surpasses
+this point in time.
+.IP "\(bu" 4
+repeating interval timer (offset = offset within interval, interval > 0, reschedule_cb = 0)
+.Sp
+In this mode the watcher will always be scheduled to time out at the next
+\&\f(CW\*(C`offset + N * interval\*(C'\fR time (for some integer N, which can also be
+negative) and then repeat, regardless of any time jumps. The \f(CW\*(C`offset\*(C'\fR
+argument is merely an offset into the \f(CW\*(C`interval\*(C'\fR periods.
+.Sp
+This can be used to create timers that do not drift with respect to the
+system clock, for example, here is an \f(CW\*(C`ev_periodic\*(C'\fR that triggers each
+hour, on the hour (with respect to \s-1UTC\s0):
+.Sp
+.Vb 1
+\& ev_periodic_set (&periodic, 0., 3600., 0);
+.Ve
+.Sp
+This doesn't mean there will always be 3600 seconds in between triggers,
+but only that the callback will be called when the system time shows a
+full hour (\s-1UTC\s0), or more correctly, when the system time is evenly divisible
+by 3600.
+.Sp
+Another way to think about it (for the mathematically inclined) is that
+\&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible
+time where \f(CW\*(C`time = offset (mod interval)\*(C'\fR, regardless of any time jumps.
+.Sp
+The \f(CW\*(C`interval\*(C'\fR \fI\s-1MUST\s0\fR be positive, and for numerical stability, the
+interval value should be higher than \f(CW\*(C`1/8192\*(C'\fR (which is around 100
+microseconds) and \f(CW\*(C`offset\*(C'\fR should be higher than \f(CW0\fR and should have
+at most a similar magnitude as the current time (say, within a factor of
+ten). Typical values for offset are, in fact, \f(CW0\fR or something between
+\&\f(CW0\fR and \f(CW\*(C`interval\*(C'\fR, which is also the recommended range.
+.Sp
+Note also that there is an upper limit to how often a timer can fire (\s-1CPU\s0
+speed for example), so if \f(CW\*(C`interval\*(C'\fR is very small then timing stability
+will of course deteriorate. Libev itself tries to be exact to be about one
+millisecond (if the \s-1OS\s0 supports it and the machine is fast enough).
+.IP "\(bu" 4
+manual reschedule mode (offset ignored, interval ignored, reschedule_cb = callback)
+.Sp
+In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`offset\*(C'\fR are both being
+ignored. Instead, each time the periodic watcher gets scheduled, the
+reschedule callback will be called with the watcher as first, and the
+current time as second argument.
+.Sp
+\&\s-1NOTE:\s0 \fIThis callback \s-1MUST NOT\s0 stop or destroy any periodic watcher, ever,
+or make \s-1ANY\s0 other event loop modifications whatsoever, unless explicitly
+allowed by documentation here\fR.
+.Sp
+If you need to stop it, return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop
+it afterwards (e.g. by starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is the
+only event loop modification you are allowed to do).
+.Sp
+The callback prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(ev_periodic
+*w, ev_tstamp now)\*(C'\fR, e.g.:
+.Sp
+.Vb 5
+\& static ev_tstamp
+\& my_rescheduler (ev_periodic *w, ev_tstamp now)
+\& {
+\& return now + 60.;
+\& }
+.Ve
+.Sp
+It must return the next time to trigger, based on the passed time value
+(that is, the lowest time value larger than to the second argument). It
+will usually be called just before the callback will be triggered, but
+might be called at other times, too.
+.Sp
+\&\s-1NOTE:\s0 \fIThis callback must always return a time that is higher than or
+equal to the passed \f(CI\*(C`now\*(C'\fI value\fR.
+.Sp
+This can be used to create very complex timers, such as a timer that
+triggers on \*(L"next midnight, local time\*(R". To do this, you would calculate
+the next midnight after \f(CW\*(C`now\*(C'\fR and return the timestamp value for
+this. Here is a (completely untested, no error checking) example on how to
+do this:
+.Sp
+.Vb 1
+\& #include <time.h>
+\&
+\& static ev_tstamp
+\& my_rescheduler (ev_periodic *w, ev_tstamp now)
+\& {
+\& time_t tnow = (time_t)now;
+\& struct tm tm;
+\& localtime_r (&tnow, &tm);
+\&
+\& tm.tm_sec = tm.tm_min = tm.tm_hour = 0; // midnight current day
+\& ++tm.tm_mday; // midnight next day
+\&
+\& return mktime (&tm);
+\& }
+.Ve
+.Sp
+Note: this code might run into trouble on days that have more then two
+midnights (beginning and end).
+.RE
+.RS 4
+.RE
+.IP "ev_periodic_again (loop, ev_periodic *)" 4
+.IX Item "ev_periodic_again (loop, ev_periodic *)"
+Simply stops and restarts the periodic watcher again. This is only useful
+when you changed some parameters or the reschedule callback would return
+a different time than the last time it was called (e.g. in a crond like
+program when the crontabs have changed).
+.IP "ev_tstamp ev_periodic_at (ev_periodic *)" 4
+.IX Item "ev_tstamp ev_periodic_at (ev_periodic *)"
+When active, returns the absolute time that the watcher is supposed
+to trigger next. This is not the same as the \f(CW\*(C`offset\*(C'\fR argument to
+\&\f(CW\*(C`ev_periodic_set\*(C'\fR, but indeed works even in interval and manual
+rescheduling modes.
+.IP "ev_tstamp offset [read\-write]" 4
+.IX Item "ev_tstamp offset [read-write]"
+When repeating, this contains the offset value, otherwise this is the
+absolute point in time (the \f(CW\*(C`offset\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR,
+although libev might modify this value for better numerical stability).
+.Sp
+Can be modified any time, but changes only take effect when the periodic
+timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
+.IP "ev_tstamp interval [read\-write]" 4
+.IX Item "ev_tstamp interval [read-write]"
+The current interval value. Can be modified any time, but changes only
+take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being
+called.
+.IP "ev_tstamp (*reschedule_cb)(ev_periodic *w, ev_tstamp now) [read\-write]" 4
+.IX Item "ev_tstamp (*reschedule_cb)(ev_periodic *w, ev_tstamp now) [read-write]"
+The current reschedule callback, or \f(CW0\fR, if this functionality is
+switched off. Can be changed any time, but changes only take effect when
+the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Call a callback every hour, or, more precisely, whenever the
+system time is divisible by 3600. The callback invocation times have
+potentially a lot of jitter, but good long-term stability.
+.PP
+.Vb 5
+\& static void
+\& clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
+\& {
+\& ... its now a full hour (UTC, or TAI or whatever your clock follows)
+\& }
+\&
+\& ev_periodic hourly_tick;
+\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
+\& ev_periodic_start (loop, &hourly_tick);
+.Ve
+.PP
+Example: The same as above, but use a reschedule callback to do it:
+.PP
+.Vb 1
+\& #include <math.h>
+\&
+\& static ev_tstamp
+\& my_scheduler_cb (ev_periodic *w, ev_tstamp now)
+\& {
+\& return now + (3600. \- fmod (now, 3600.));
+\& }
+\&
+\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
+.Ve
+.PP
+Example: Call a callback every hour, starting now:
+.PP
+.Vb 4
+\& ev_periodic hourly_tick;
+\& ev_periodic_init (&hourly_tick, clock_cb,
+\& fmod (ev_now (loop), 3600.), 3600., 0);
+\& ev_periodic_start (loop, &hourly_tick);
+.Ve
+.ie n .SS """ev_signal"" \- signal me when a signal gets signalled!"
+.el .SS "\f(CWev_signal\fP \- signal me when a signal gets signalled!"
+.IX Subsection "ev_signal - signal me when a signal gets signalled!"
+Signal watchers will trigger an event when the process receives a specific
+signal one or more times. Even though signals are very asynchronous, libev
+will try its best to deliver signals synchronously, i.e. as part of the
+normal event processing, like any other event.
+.PP
+If you want signals to be delivered truly asynchronously, just use
+\&\f(CW\*(C`sigaction\*(C'\fR as you would do without libev and forget about sharing
+the signal. You can even use \f(CW\*(C`ev_async\*(C'\fR from a signal handler to
+synchronously wake up an event loop.
+.PP
+You can configure as many watchers as you like for the same signal, but
+only within the same loop, i.e. you can watch for \f(CW\*(C`SIGINT\*(C'\fR in your
+default loop and for \f(CW\*(C`SIGIO\*(C'\fR in another loop, but you cannot watch for
+\&\f(CW\*(C`SIGINT\*(C'\fR in both the default loop and another loop at the same time. At
+the moment, \f(CW\*(C`SIGCHLD\*(C'\fR is permanently tied to the default loop.
+.PP
+Only after the first watcher for a signal is started will libev actually
+register something with the kernel. It thus coexists with your own signal
+handlers as long as you don't register any with libev for the same signal.
+.PP
+If possible and supported, libev will install its handlers with
+\&\f(CW\*(C`SA_RESTART\*(C'\fR (or equivalent) behaviour enabled, so system calls should
+not be unduly interrupted. If you have a problem with system calls getting
+interrupted by signals you can block all signals in an \f(CW\*(C`ev_check\*(C'\fR watcher
+and unblock them in an \f(CW\*(C`ev_prepare\*(C'\fR watcher.
+.PP
+\fIThe special problem of inheritance over fork/execve/pthread_create\fR
+.IX Subsection "The special problem of inheritance over fork/execve/pthread_create"
+.PP
+Both the signal mask (\f(CW\*(C`sigprocmask\*(C'\fR) and the signal disposition
+(\f(CW\*(C`sigaction\*(C'\fR) are unspecified after starting a signal watcher (and after
+stopping it again), that is, libev might or might not block the signal,
+and might or might not set or restore the installed signal handler (but
+see \f(CW\*(C`EVFLAG_NOSIGMASK\*(C'\fR).
+.PP
+While this does not matter for the signal disposition (libev never
+sets signals to \f(CW\*(C`SIG_IGN\*(C'\fR, so handlers will be reset to \f(CW\*(C`SIG_DFL\*(C'\fR on
+\&\f(CW\*(C`execve\*(C'\fR), this matters for the signal mask: many programs do not expect
+certain signals to be blocked.
+.PP
+This means that before calling \f(CW\*(C`exec\*(C'\fR (from the child) you should reset
+the signal mask to whatever \*(L"default\*(R" you expect (all clear is a good
+choice usually).
+.PP
+The simplest way to ensure that the signal mask is reset in the child is
+to install a fork handler with \f(CW\*(C`pthread_atfork\*(C'\fR that resets it. That will
+catch fork calls done by libraries (such as the libc) as well.
+.PP
+In current versions of libev, the signal will not be blocked indefinitely
+unless you use the \f(CW\*(C`signalfd\*(C'\fR \s-1API\s0 (\f(CW\*(C`EV_SIGNALFD\*(C'\fR). While this reduces
+the window of opportunity for problems, it will not go away, as libev
+\&\fIhas\fR to modify the signal mask, at least temporarily.
+.PP
+So I can't stress this enough: \fIIf you do not reset your signal mask when
+you expect it to be empty, you have a race condition in your code\fR. This
+is not a libev-specific thing, this is true for most event libraries.
+.PP
+\fIThe special problem of threads signal handling\fR
+.IX Subsection "The special problem of threads signal handling"
+.PP
+\&\s-1POSIX\s0 threads has problematic signal handling semantics, specifically,
+a lot of functionality (sigfd, sigwait etc.) only really works if all
+threads in a process block signals, which is hard to achieve.
+.PP
+When you want to use sigwait (or mix libev signal handling with your own
+for the same signals), you can tackle this problem by globally blocking
+all signals before creating any threads (or creating them with a fully set
+sigprocmask) and also specifying the \f(CW\*(C`EVFLAG_NOSIGMASK\*(C'\fR when creating
+loops. Then designate one thread as \*(L"signal receiver thread\*(R" which handles
+these signals. You can pass on any signals that libev might be interested
+in by calling \f(CW\*(C`ev_feed_signal\*(C'\fR.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_signal_init (ev_signal *, callback, int signum)" 4
+.IX Item "ev_signal_init (ev_signal *, callback, int signum)"
+.PD 0
+.IP "ev_signal_set (ev_signal *, int signum)" 4
+.IX Item "ev_signal_set (ev_signal *, int signum)"
+.PD
+Configures the watcher to trigger on the given signal number (usually one
+of the \f(CW\*(C`SIGxxx\*(C'\fR constants).
+.IP "int signum [read\-only]" 4
+.IX Item "int signum [read-only]"
+The signal the watcher watches out for.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Try to exit cleanly on \s-1SIGINT.\s0
+.PP
+.Vb 5
+\& static void
+\& sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
+\& {
+\& ev_break (loop, EVBREAK_ALL);
+\& }
+\&
+\& ev_signal signal_watcher;
+\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
+\& ev_signal_start (loop, &signal_watcher);
+.Ve
+.ie n .SS """ev_child"" \- watch out for process status changes"
+.el .SS "\f(CWev_child\fP \- watch out for process status changes"
+.IX Subsection "ev_child - watch out for process status changes"
+Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to
+some child status changes (most typically when a child of yours dies or
+exits). It is permissible to install a child watcher \fIafter\fR the child
+has been forked (which implies it might have already exited), as long
+as the event loop isn't entered (or is continued from a watcher), i.e.,
+forking and then immediately registering a watcher for the child is fine,
+but forking and registering a watcher a few event loop iterations later or
+in the next callback invocation is not.
+.PP
+Only the default event loop is capable of handling signals, and therefore
+you can only register child watchers in the default event loop.
+.PP
+Due to some design glitches inside libev, child watchers will always be
+handled at maximum priority (their priority is set to \f(CW\*(C`EV_MAXPRI\*(C'\fR by
+libev)
+.PP
+\fIProcess Interaction\fR
+.IX Subsection "Process Interaction"
+.PP
+Libev grabs \f(CW\*(C`SIGCHLD\*(C'\fR as soon as the default event loop is
+initialised. This is necessary to guarantee proper behaviour even if the
+first child watcher is started after the child exits. The occurrence
+of \f(CW\*(C`SIGCHLD\*(C'\fR is recorded asynchronously, but child reaping is done
+synchronously as part of the event loop processing. Libev always reaps all
+children, even ones not watched.
+.PP
+\fIOverriding the Built-In Processing\fR
+.IX Subsection "Overriding the Built-In Processing"
+.PP
+Libev offers no special support for overriding the built-in child
+processing, but if your application collides with libev's default child
+handler, you can override it easily by installing your own handler for
+\&\f(CW\*(C`SIGCHLD\*(C'\fR after initialising the default loop, and making sure the
+default loop never gets destroyed. You are encouraged, however, to use an
+event-based approach to child reaping and thus use libev's support for
+that, so other libev users can use \f(CW\*(C`ev_child\*(C'\fR watchers freely.
+.PP
+\fIStopping the Child Watcher\fR
+.IX Subsection "Stopping the Child Watcher"
+.PP
+Currently, the child watcher never gets stopped, even when the
+child terminates, so normally one needs to stop the watcher in the
+callback. Future versions of libev might stop the watcher automatically
+when a child exit is detected (calling \f(CW\*(C`ev_child_stop\*(C'\fR twice is not a
+problem).
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_child_init (ev_child *, callback, int pid, int trace)" 4
+.IX Item "ev_child_init (ev_child *, callback, int pid, int trace)"
+.PD 0
+.IP "ev_child_set (ev_child *, int pid, int trace)" 4
+.IX Item "ev_child_set (ev_child *, int pid, int trace)"
+.PD
+Configures the watcher to wait for status changes of process \f(CW\*(C`pid\*(C'\fR (or
+\&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look
+at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see
+the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems
+\&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the
+process causing the status change. \f(CW\*(C`trace\*(C'\fR must be either \f(CW0\fR (only
+activate the watcher when the process terminates) or \f(CW1\fR (additionally
+activate the watcher when the process is stopped or continued).
+.IP "int pid [read\-only]" 4
+.IX Item "int pid [read-only]"
+The process id this watcher watches out for, or \f(CW0\fR, meaning any process id.
+.IP "int rpid [read\-write]" 4
+.IX Item "int rpid [read-write]"
+The process id that detected a status change.
+.IP "int rstatus [read\-write]" 4
+.IX Item "int rstatus [read-write]"
+The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems
+\&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details).
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: \f(CW\*(C`fork()\*(C'\fR a new process and install a child handler to wait for
+its completion.
+.PP
+.Vb 1
+\& ev_child cw;
+\&
+\& static void
+\& child_cb (EV_P_ ev_child *w, int revents)
+\& {
+\& ev_child_stop (EV_A_ w);
+\& printf ("process %d exited with status %x\en", w\->rpid, w\->rstatus);
+\& }
+\&
+\& pid_t pid = fork ();
+\&
+\& if (pid < 0)
+\& // error
+\& else if (pid == 0)
+\& {
+\& // the forked child executes here
+\& exit (1);
+\& }
+\& else
+\& {
+\& ev_child_init (&cw, child_cb, pid, 0);
+\& ev_child_start (EV_DEFAULT_ &cw);
+\& }
+.Ve
+.ie n .SS """ev_stat"" \- did the file attributes just change?"
+.el .SS "\f(CWev_stat\fP \- did the file attributes just change?"
+.IX Subsection "ev_stat - did the file attributes just change?"
+This watches a file system path for attribute changes. That is, it calls
+\&\f(CW\*(C`stat\*(C'\fR on that path in regular intervals (or when the \s-1OS\s0 says it changed)
+and sees if it changed compared to the last time, invoking the callback
+if it did. Starting the watcher \f(CW\*(C`stat\*(C'\fR's the file, so only changes that
+happen after the watcher has been started will be reported.
+.PP
+The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does
+not exist\*(R" is a status change like any other. The condition \*(L"path does not
+exist\*(R" (or more correctly \*(L"path cannot be stat'ed\*(R") is signified by the
+\&\f(CW\*(C`st_nlink\*(C'\fR field being zero (which is otherwise always forced to be at
+least one) and all the other fields of the stat buffer having unspecified
+contents.
+.PP
+The path \fImust not\fR end in a slash or contain special components such as
+\&\f(CW\*(C`.\*(C'\fR or \f(CW\*(C`..\*(C'\fR. The path \fIshould\fR be absolute: If it is relative and
+your working directory changes, then the behaviour is undefined.
+.PP
+Since there is no portable change notification interface available, the
+portable implementation simply calls \f(CWstat(2)\fR regularly on the path
+to see if it changed somehow. You can specify a recommended polling
+interval for this case. If you specify a polling interval of \f(CW0\fR (highly
+recommended!) then a \fIsuitable, unspecified default\fR value will be used
+(which you can expect to be around five seconds, although this might
+change dynamically). Libev will also impose a minimum interval which is
+currently around \f(CW0.1\fR, but that's usually overkill.
+.PP
+This watcher type is not meant for massive numbers of stat watchers,
+as even with OS-supported change notifications, this can be
+resource-intensive.
+.PP
+At the time of this writing, the only OS-specific interface implemented
+is the Linux inotify interface (implementing kqueue support is left as an
+exercise for the reader. Note, however, that the author sees no way of
+implementing \f(CW\*(C`ev_stat\*(C'\fR semantics with kqueue, except as a hint).
+.PP
+\fI\s-1ABI\s0 Issues (Largefile Support)\fR
+.IX Subsection "ABI Issues (Largefile Support)"
+.PP
+Libev by default (unless the user overrides this) uses the default
+compilation environment, which means that on systems with large file
+support disabled by default, you get the 32 bit version of the stat
+structure. When using the library from programs that change the \s-1ABI\s0 to
+use 64 bit file offsets the programs will fail. In that case you have to
+compile libev with the same flags to get binary compatibility. This is
+obviously the case with any flags that change the \s-1ABI,\s0 but the problem is
+most noticeably displayed with ev_stat and large file support.
+.PP
+The solution for this is to lobby your distribution maker to make large
+file interfaces available by default (as e.g. FreeBSD does) and not
+optional. Libev cannot simply switch on large file support because it has
+to exchange stat structures with application programs compiled using the
+default compilation environment.
+.PP
+\fIInotify and Kqueue\fR
+.IX Subsection "Inotify and Kqueue"
+.PP
+When \f(CW\*(C`inotify (7)\*(C'\fR support has been compiled into libev and present at
+runtime, it will be used to speed up change detection where possible. The
+inotify descriptor will be created lazily when the first \f(CW\*(C`ev_stat\*(C'\fR
+watcher is being started.
+.PP
+Inotify presence does not change the semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers
+except that changes might be detected earlier, and in some cases, to avoid
+making regular \f(CW\*(C`stat\*(C'\fR calls. Even in the presence of inotify support
+there are many cases where libev has to resort to regular \f(CW\*(C`stat\*(C'\fR polling,
+but as long as kernel 2.6.25 or newer is used (2.6.24 and older have too
+many bugs), the path exists (i.e. stat succeeds), and the path resides on
+a local filesystem (libev currently assumes only ext2/3, jfs, reiserfs and
+xfs are fully working) libev usually gets away without polling.
+.PP
+There is no support for kqueue, as apparently it cannot be used to
+implement this functionality, due to the requirement of having a file
+descriptor open on the object at all times, and detecting renames, unlinks
+etc. is difficult.
+.PP
+\fI\f(CI\*(C`stat ()\*(C'\fI is a synchronous operation\fR
+.IX Subsection "stat () is a synchronous operation"
+.PP
+Libev doesn't normally do any kind of I/O itself, and so is not blocking
+the process. The exception are \f(CW\*(C`ev_stat\*(C'\fR watchers \- those call \f(CW\*(C`stat
+()\*(C'\fR, which is a synchronous operation.
+.PP
+For local paths, this usually doesn't matter: unless the system is very
+busy or the intervals between stat's are large, a stat call will be fast,
+as the path data is usually in memory already (except when starting the
+watcher).
+.PP
+For networked file systems, calling \f(CW\*(C`stat ()\*(C'\fR can block an indefinite
+time due to network issues, and even under good conditions, a stat call
+often takes multiple milliseconds.
+.PP
+Therefore, it is best to avoid using \f(CW\*(C`ev_stat\*(C'\fR watchers on networked
+paths, although this is fully supported by libev.
+.PP
+\fIThe special problem of stat time resolution\fR
+.IX Subsection "The special problem of stat time resolution"
+.PP
+The \f(CW\*(C`stat ()\*(C'\fR system call only supports full-second resolution portably,
+and even on systems where the resolution is higher, most file systems
+still only support whole seconds.
+.PP
+That means that, if the time is the only thing that changes, you can
+easily miss updates: on the first update, \f(CW\*(C`ev_stat\*(C'\fR detects a change and
+calls your callback, which does something. When there is another update
+within the same second, \f(CW\*(C`ev_stat\*(C'\fR will be unable to detect unless the
+stat data does change in other ways (e.g. file size).
+.PP
+The solution to this is to delay acting on a change for slightly more
+than a second (or till slightly after the next full second boundary), using
+a roughly one-second-delay \f(CW\*(C`ev_timer\*(C'\fR (e.g. \f(CW\*(C`ev_timer_set (w, 0., 1.02);
+ev_timer_again (loop, w)\*(C'\fR).
+.PP
+The \f(CW.02\fR offset is added to work around small timing inconsistencies
+of some operating systems (where the second counter of the current time
+might be be delayed. One such system is the Linux kernel, where a call to
+\&\f(CW\*(C`gettimeofday\*(C'\fR might return a timestamp with a full second later than
+a subsequent \f(CW\*(C`time\*(C'\fR call \- if the equivalent of \f(CW\*(C`time ()\*(C'\fR is used to
+update file times then there will be a small window where the kernel uses
+the previous second to update file times but libev might already execute
+the timer callback).
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4
+.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)"
+.PD 0
+.IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4
+.IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)"
+.PD
+Configures the watcher to wait for status changes of the given
+\&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to
+be detected and should normally be specified as \f(CW0\fR to let libev choose
+a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same
+path for as long as the watcher is active.
+.Sp
+The callback will receive an \f(CW\*(C`EV_STAT\*(C'\fR event when a change was detected,
+relative to the attributes at the time the watcher was started (or the
+last change was detected).
+.IP "ev_stat_stat (loop, ev_stat *)" 4
+.IX Item "ev_stat_stat (loop, ev_stat *)"
+Updates the stat buffer immediately with new values. If you change the
+watched path in your callback, you could call this function to avoid
+detecting this change (while introducing a race condition if you are not
+the only one changing the path). Can also be useful simply to find out the
+new values.
+.IP "ev_statdata attr [read\-only]" 4
+.IX Item "ev_statdata attr [read-only]"
+The most-recently detected attributes of the file. Although the type is
+\&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types
+suitable for your system, but you can only rely on the POSIX-standardised
+members to be present. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there was
+some error while \f(CW\*(C`stat\*(C'\fRing the file.
+.IP "ev_statdata prev [read\-only]" 4
+.IX Item "ev_statdata prev [read-only]"
+The previous attributes of the file. The callback gets invoked whenever
+\&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR, or, more precisely, one or more of these members
+differ: \f(CW\*(C`st_dev\*(C'\fR, \f(CW\*(C`st_ino\*(C'\fR, \f(CW\*(C`st_mode\*(C'\fR, \f(CW\*(C`st_nlink\*(C'\fR, \f(CW\*(C`st_uid\*(C'\fR,
+\&\f(CW\*(C`st_gid\*(C'\fR, \f(CW\*(C`st_rdev\*(C'\fR, \f(CW\*(C`st_size\*(C'\fR, \f(CW\*(C`st_atime\*(C'\fR, \f(CW\*(C`st_mtime\*(C'\fR, \f(CW\*(C`st_ctime\*(C'\fR.
+.IP "ev_tstamp interval [read\-only]" 4
+.IX Item "ev_tstamp interval [read-only]"
+The specified interval.
+.IP "const char *path [read\-only]" 4
+.IX Item "const char *path [read-only]"
+The file system path that is being watched.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes.
+.PP
+.Vb 10
+\& static void
+\& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)
+\& {
+\& /* /etc/passwd changed in some way */
+\& if (w\->attr.st_nlink)
+\& {
+\& printf ("passwd current size %ld\en", (long)w\->attr.st_size);
+\& printf ("passwd current atime %ld\en", (long)w\->attr.st_mtime);
+\& printf ("passwd current mtime %ld\en", (long)w\->attr.st_mtime);
+\& }
+\& else
+\& /* you shalt not abuse printf for puts */
+\& puts ("wow, /etc/passwd is not there, expect problems. "
+\& "if this is windows, they already arrived\en");
+\& }
+\&
+\& ...
+\& ev_stat passwd;
+\&
+\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
+\& ev_stat_start (loop, &passwd);
+.Ve
+.PP
+Example: Like above, but additionally use a one-second delay so we do not
+miss updates (however, frequent updates will delay processing, too, so
+one might do the work both on \f(CW\*(C`ev_stat\*(C'\fR callback invocation \fIand\fR on
+\&\f(CW\*(C`ev_timer\*(C'\fR callback invocation).
+.PP
+.Vb 2
+\& static ev_stat passwd;
+\& static ev_timer timer;
+\&
+\& static void
+\& timer_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& ev_timer_stop (EV_A_ w);
+\&
+\& /* now it\*(Aqs one second after the most recent passwd change */
+\& }
+\&
+\& static void
+\& stat_cb (EV_P_ ev_stat *w, int revents)
+\& {
+\& /* reset the one\-second timer */
+\& ev_timer_again (EV_A_ &timer);
+\& }
+\&
+\& ...
+\& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
+\& ev_stat_start (loop, &passwd);
+\& ev_timer_init (&timer, timer_cb, 0., 1.02);
+.Ve
+.ie n .SS """ev_idle"" \- when you've got nothing better to do..."
+.el .SS "\f(CWev_idle\fP \- when you've got nothing better to do..."
+.IX Subsection "ev_idle - when you've got nothing better to do..."
+Idle watchers trigger events when no other events of the same or higher
+priority are pending (prepare, check and other idle watchers do not count
+as receiving \*(L"events\*(R").
+.PP
+That is, as long as your process is busy handling sockets or timeouts
+(or even signals, imagine) of the same or higher priority it will not be
+triggered. But when your process is idle (or only lower-priority watchers
+are pending), the idle watchers are being called once per event loop
+iteration \- until stopped, that is, or your process receives more events
+and becomes busy again with higher priority stuff.
+.PP
+The most noteworthy effect is that as long as any idle watchers are
+active, the process will not block when waiting for new events.
+.PP
+Apart from keeping your process non-blocking (which is a useful
+effect on its own sometimes), idle watchers are a good place to do
+\&\*(L"pseudo-background processing\*(R", or delay processing stuff to after the
+event loop has handled all outstanding events.
+.PP
+\fIAbusing an \f(CI\*(C`ev_idle\*(C'\fI watcher for its side-effect\fR
+.IX Subsection "Abusing an ev_idle watcher for its side-effect"
+.PP
+As long as there is at least one active idle watcher, libev will never
+sleep unnecessarily. Or in other words, it will loop as fast as possible.
+For this to work, the idle watcher doesn't need to be invoked at all \- the
+lowest priority will do.
+.PP
+This mode of operation can be useful together with an \f(CW\*(C`ev_check\*(C'\fR watcher,
+to do something on each event loop iteration \- for example to balance load
+between different connections.
+.PP
+See \*(L"Abusing an ev_check watcher for its side-effect\*(R" for a longer
+example.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_idle_init (ev_idle *, callback)" 4
+.IX Item "ev_idle_init (ev_idle *, callback)"
+Initialises and configures the idle watcher \- it has no parameters of any
+kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless,
+believe me.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the
+callback, free it. Also, use no error checking, as usual.
+.PP
+.Vb 5
+\& static void
+\& idle_cb (struct ev_loop *loop, ev_idle *w, int revents)
+\& {
+\& // stop the watcher
+\& ev_idle_stop (loop, w);
+\&
+\& // now we can free it
+\& free (w);
+\&
+\& // now do something you wanted to do when the program has
+\& // no longer anything immediate to do.
+\& }
+\&
+\& ev_idle *idle_watcher = malloc (sizeof (ev_idle));
+\& ev_idle_init (idle_watcher, idle_cb);
+\& ev_idle_start (loop, idle_watcher);
+.Ve
+.ie n .SS """ev_prepare"" and ""ev_check"" \- customise your event loop!"
+.el .SS "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!"
+.IX Subsection "ev_prepare and ev_check - customise your event loop!"
+Prepare and check watchers are often (but not always) used in pairs:
+prepare watchers get invoked before the process blocks and check watchers
+afterwards.
+.PP
+You \fImust not\fR call \f(CW\*(C`ev_run\*(C'\fR (or similar functions that enter the
+current event loop) or \f(CW\*(C`ev_loop_fork\*(C'\fR from either \f(CW\*(C`ev_prepare\*(C'\fR or
+\&\f(CW\*(C`ev_check\*(C'\fR watchers. Other loops than the current one are fine,
+however. The rationale behind this is that you do not need to check
+for recursion in those watchers, i.e. the sequence will always be
+\&\f(CW\*(C`ev_prepare\*(C'\fR, blocking, \f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each
+kind they will always be called in pairs bracketing the blocking call.
+.PP
+Their main purpose is to integrate other event mechanisms into libev and
+their use is somewhat advanced. They could be used, for example, to track
+variable changes, implement your own watchers, integrate net-snmp or a
+coroutine library and lots more. They are also occasionally useful if
+you cache some data and want to flush it before blocking (for example,
+in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR
+watcher).
+.PP
+This is done by examining in each prepare call which file descriptors
+need to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers
+for them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many
+libraries provide exactly this functionality). Then, in the check watcher,
+you check for any events that occurred (by checking the pending status
+of all watchers and stopping them) and call back into the library. The
+I/O and timer callbacks will never actually be called (but must be valid
+nevertheless, because you never know, you know?).
+.PP
+As another example, the Perl Coro module uses these hooks to integrate
+coroutines into libev programs, by yielding to other active coroutines
+during each prepare and only letting the process block if no coroutines
+are ready to run (it's actually more complicated: it only runs coroutines
+with priority higher than or equal to the event loop and one coroutine
+of lower priority, but only once, using idle watchers to keep the event
+loop from blocking if lower-priority coroutines are active, thus mapping
+low-priority coroutines to idle/background tasks).
+.PP
+When used for this purpose, it is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers
+highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) priority, to ensure that they are being run before
+any other watchers after the poll (this doesn't matter for \f(CW\*(C`ev_prepare\*(C'\fR
+watchers).
+.PP
+Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, too) should not
+activate (\*(L"feed\*(R") events into libev. While libev fully supports this, they
+might get executed before other \f(CW\*(C`ev_check\*(C'\fR watchers did their job. As
+\&\f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other (non-libev) event
+loops those other event loops might be in an unusable state until their
+\&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with
+others).
+.PP
+\fIAbusing an \f(CI\*(C`ev_check\*(C'\fI watcher for its side-effect\fR
+.IX Subsection "Abusing an ev_check watcher for its side-effect"
+.PP
+\&\f(CW\*(C`ev_check\*(C'\fR (and less often also \f(CW\*(C`ev_prepare\*(C'\fR) watchers can also be
+useful because they are called once per event loop iteration. For
+example, if you want to handle a large number of connections fairly, you
+normally only do a bit of work for each active connection, and if there
+is more work to do, you wait for the next event loop iteration, so other
+connections have a chance of making progress.
+.PP
+Using an \f(CW\*(C`ev_check\*(C'\fR watcher is almost enough: it will be called on the
+next event loop iteration. However, that isn't as soon as possible \-
+without external events, your \f(CW\*(C`ev_check\*(C'\fR watcher will not be invoked.
+.PP
+This is where \f(CW\*(C`ev_idle\*(C'\fR watchers come in handy \- all you need is a
+single global idle watcher that is active as long as you have one active
+\&\f(CW\*(C`ev_check\*(C'\fR watcher. The \f(CW\*(C`ev_idle\*(C'\fR watcher makes sure the event loop
+will not sleep, and the \f(CW\*(C`ev_check\*(C'\fR watcher makes sure a callback gets
+invoked. Neither watcher alone can do that.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_prepare_init (ev_prepare *, callback)" 4
+.IX Item "ev_prepare_init (ev_prepare *, callback)"
+.PD 0
+.IP "ev_check_init (ev_check *, callback)" 4
+.IX Item "ev_check_init (ev_check *, callback)"
+.PD
+Initialises and configures the prepare or check watcher \- they have no
+parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR
+macros, but using them is utterly, utterly, utterly and completely
+pointless.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+There are a number of principal ways to embed other event loops or modules
+into libev. Here are some ideas on how to include libadns into libev
+(there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could
+use as a working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR embeds a
+Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 into the
+Glib event loop).
+.PP
+Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler,
+and in a check watcher, destroy them and call into libadns. What follows
+is pseudo-code only of course. This requires you to either use a low
+priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as
+the callbacks for the IO/timeout watchers might not have been called yet.
+.PP
+.Vb 2
+\& static ev_io iow [nfd];
+\& static ev_timer tw;
+\&
+\& static void
+\& io_cb (struct ev_loop *loop, ev_io *w, int revents)
+\& {
+\& }
+\&
+\& // create io watchers for each fd and a timer before blocking
+\& static void
+\& adns_prepare_cb (struct ev_loop *loop, ev_prepare *w, int revents)
+\& {
+\& int timeout = 3600000;
+\& struct pollfd fds [nfd];
+\& // actual code will need to loop here and realloc etc.
+\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
+\&
+\& /* the callback is illegal, but won\*(Aqt be called as we stop during check */
+\& ev_timer_init (&tw, 0, timeout * 1e\-3, 0.);
+\& ev_timer_start (loop, &tw);
+\&
+\& // create one ev_io per pollfd
+\& for (int i = 0; i < nfd; ++i)
+\& {
+\& ev_io_init (iow + i, io_cb, fds [i].fd,
+\& ((fds [i].events & POLLIN ? EV_READ : 0)
+\& | (fds [i].events & POLLOUT ? EV_WRITE : 0)));
+\&
+\& fds [i].revents = 0;
+\& ev_io_start (loop, iow + i);
+\& }
+\& }
+\&
+\& // stop all watchers after blocking
+\& static void
+\& adns_check_cb (struct ev_loop *loop, ev_check *w, int revents)
+\& {
+\& ev_timer_stop (loop, &tw);
+\&
+\& for (int i = 0; i < nfd; ++i)
+\& {
+\& // set the relevant poll flags
+\& // could also call adns_processreadable etc. here
+\& struct pollfd *fd = fds + i;
+\& int revents = ev_clear_pending (iow + i);
+\& if (revents & EV_READ ) fd\->revents |= fd\->events & POLLIN;
+\& if (revents & EV_WRITE) fd\->revents |= fd\->events & POLLOUT;
+\&
+\& // now stop the watcher
+\& ev_io_stop (loop, iow + i);
+\& }
+\&
+\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
+\& }
+.Ve
+.PP
+Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR
+in the prepare watcher and would dispose of the check watcher.
+.PP
+Method 3: If the module to be embedded supports explicit event
+notification (libadns does), you can also make use of the actual watcher
+callbacks, and only destroy/create the watchers in the prepare watcher.
+.PP
+.Vb 5
+\& static void
+\& timer_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& adns_state ads = (adns_state)w\->data;
+\& update_now (EV_A);
+\&
+\& adns_processtimeouts (ads, &tv_now);
+\& }
+\&
+\& static void
+\& io_cb (EV_P_ ev_io *w, int revents)
+\& {
+\& adns_state ads = (adns_state)w\->data;
+\& update_now (EV_A);
+\&
+\& if (revents & EV_READ ) adns_processreadable (ads, w\->fd, &tv_now);
+\& if (revents & EV_WRITE) adns_processwriteable (ads, w\->fd, &tv_now);
+\& }
+\&
+\& // do not ever call adns_afterpoll
+.Ve
+.PP
+Method 4: Do not use a prepare or check watcher because the module you
+want to embed is not flexible enough to support it. Instead, you can
+override their poll function. The drawback with this solution is that the
+main loop is now no longer controllable by \s-1EV.\s0 The \f(CW\*(C`Glib::EV\*(C'\fR module uses
+this approach, effectively embedding \s-1EV\s0 as a client into the horrible
+libglib event loop.
+.PP
+.Vb 4
+\& static gint
+\& event_poll_func (GPollFD *fds, guint nfds, gint timeout)
+\& {
+\& int got_events = 0;
+\&
+\& for (n = 0; n < nfds; ++n)
+\& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events
+\&
+\& if (timeout >= 0)
+\& // create/start timer
+\&
+\& // poll
+\& ev_run (EV_A_ 0);
+\&
+\& // stop timer again
+\& if (timeout >= 0)
+\& ev_timer_stop (EV_A_ &to);
+\&
+\& // stop io watchers again \- their callbacks should have set
+\& for (n = 0; n < nfds; ++n)
+\& ev_io_stop (EV_A_ iow [n]);
+\&
+\& return got_events;
+\& }
+.Ve
+.ie n .SS """ev_embed"" \- when one backend isn't enough..."
+.el .SS "\f(CWev_embed\fP \- when one backend isn't enough..."
+.IX Subsection "ev_embed - when one backend isn't enough..."
+This is a rather advanced watcher type that lets you embed one event loop
+into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded
+loop, other types of watchers might be handled in a delayed or incorrect
+fashion and must not be used).
+.PP
+There are primarily two reasons you would want that: work around bugs and
+prioritise I/O.
+.PP
+As an example for a bug workaround, the kqueue backend might only support
+sockets on some platform, so it is unusable as generic backend, but you
+still want to make use of it because you have many sockets and it scales
+so nicely. In this case, you would create a kqueue-based loop and embed
+it into your default loop (which might use e.g. poll). Overall operation
+will be a bit slower because first libev has to call \f(CW\*(C`poll\*(C'\fR and then
+\&\f(CW\*(C`kevent\*(C'\fR, but at least you can use both mechanisms for what they are
+best: \f(CW\*(C`kqueue\*(C'\fR for scalable sockets and \f(CW\*(C`poll\*(C'\fR if you want it to work :)
+.PP
+As for prioritising I/O: under rare circumstances you have the case where
+some fds have to be watched and handled very quickly (with low latency),
+and even priorities and idle watchers might have too much overhead. In
+this case you would put all the high priority stuff in one loop and all
+the rest in a second one, and embed the second one in the first.
+.PP
+As long as the watcher is active, the callback will be invoked every
+time there might be events pending in the embedded loop. The callback
+must then call \f(CW\*(C`ev_embed_sweep (mainloop, watcher)\*(C'\fR to make a single
+sweep and invoke their callbacks (the callback doesn't need to invoke the
+\&\f(CW\*(C`ev_embed_sweep\*(C'\fR function directly, it could also start an idle watcher
+to give the embedded loop strictly lower priority for example).
+.PP
+You can also set the callback to \f(CW0\fR, in which case the embed watcher
+will automatically execute the embedded loop sweep whenever necessary.
+.PP
+Fork detection will be handled transparently while the \f(CW\*(C`ev_embed\*(C'\fR watcher
+is active, i.e., the embedded loop will automatically be forked when the
+embedding loop forks. In other cases, the user is responsible for calling
+\&\f(CW\*(C`ev_loop_fork\*(C'\fR on the embedded loop.
+.PP
+Unfortunately, not all backends are embeddable: only the ones returned by
+\&\f(CW\*(C`ev_embeddable_backends\*(C'\fR are, which, unfortunately, does not include any
+portable one.
+.PP
+So when you want to use this feature you will always have to be prepared
+that you cannot get an embeddable loop. The recommended way to get around
+this is to have a separate variables for your embeddable loop, try to
+create it, and if that fails, use the normal loop for everything.
+.PP
+\fI\f(CI\*(C`ev_embed\*(C'\fI and fork\fR
+.IX Subsection "ev_embed and fork"
+.PP
+While the \f(CW\*(C`ev_embed\*(C'\fR watcher is running, forks in the embedding loop will
+automatically be applied to the embedded loop as well, so no special
+fork handling is required in that case. When the watcher is not running,
+however, it is still the task of the libev user to call \f(CW\*(C`ev_loop_fork ()\*(C'\fR
+as applicable.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4
+.IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)"
+.PD 0
+.IP "ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)" 4
+.IX Item "ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)"
+.PD
+Configures the watcher to embed the given loop, which must be
+embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be
+invoked automatically, otherwise it is the responsibility of the callback
+to invoke it (it will continue to be called until the sweep has been done,
+if you do not want that, you need to temporarily stop the embed watcher).
+.IP "ev_embed_sweep (loop, ev_embed *)" 4
+.IX Item "ev_embed_sweep (loop, ev_embed *)"
+Make a single, non-blocking sweep over the embedded loop. This works
+similarly to \f(CW\*(C`ev_run (embedded_loop, EVRUN_NOWAIT)\*(C'\fR, but in the most
+appropriate way for embedded loops.
+.IP "struct ev_loop *other [read\-only]" 4
+.IX Item "struct ev_loop *other [read-only]"
+The embedded event loop.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Try to get an embeddable event loop and embed it into the default
+event loop. If that is not possible, use the default loop. The default
+loop is stored in \f(CW\*(C`loop_hi\*(C'\fR, while the embeddable loop is stored in
+\&\f(CW\*(C`loop_lo\*(C'\fR (which is \f(CW\*(C`loop_hi\*(C'\fR in the case no embeddable loop can be
+used).
+.PP
+.Vb 3
+\& struct ev_loop *loop_hi = ev_default_init (0);
+\& struct ev_loop *loop_lo = 0;
+\& ev_embed embed;
+\&
+\& // see if there is a chance of getting one that works
+\& // (remember that a flags value of 0 means autodetection)
+\& loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
+\& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
+\& : 0;
+\&
+\& // if we got one, then embed it, otherwise default to loop_hi
+\& if (loop_lo)
+\& {
+\& ev_embed_init (&embed, 0, loop_lo);
+\& ev_embed_start (loop_hi, &embed);
+\& }
+\& else
+\& loop_lo = loop_hi;
+.Ve
+.PP
+Example: Check if kqueue is available but not recommended and create
+a kqueue backend for use with sockets (which usually work with any
+kqueue implementation). Store the kqueue/socket\-only event loop in
+\&\f(CW\*(C`loop_socket\*(C'\fR. (One might optionally use \f(CW\*(C`EVFLAG_NOENV\*(C'\fR, too).
+.PP
+.Vb 3
+\& struct ev_loop *loop = ev_default_init (0);
+\& struct ev_loop *loop_socket = 0;
+\& ev_embed embed;
+\&
+\& if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
+\& if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
+\& {
+\& ev_embed_init (&embed, 0, loop_socket);
+\& ev_embed_start (loop, &embed);
+\& }
+\&
+\& if (!loop_socket)
+\& loop_socket = loop;
+\&
+\& // now use loop_socket for all sockets, and loop for everything else
+.Ve
+.ie n .SS """ev_fork"" \- the audacity to resume the event loop after a fork"
+.el .SS "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
+.IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
+Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because
+whoever is a good citizen cared to tell libev about it by calling
+\&\f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the event loop blocks next
+and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, and only in the child
+after the fork. If whoever good citizen calling \f(CW\*(C`ev_default_fork\*(C'\fR cheats
+and calls it in the wrong process, the fork handlers will be invoked, too,
+of course.
+.PP
+\fIThe special problem of life after fork \- how is it possible?\fR
+.IX Subsection "The special problem of life after fork - how is it possible?"
+.PP
+Most uses of \f(CW\*(C`fork ()\*(C'\fR consist of forking, then some simple calls to set
+up/change the process environment, followed by a call to \f(CW\*(C`exec()\*(C'\fR. This
+sequence should be handled by libev without any problems.
+.PP
+This changes when the application actually wants to do event handling
+in the child, or both parent in child, in effect \*(L"continuing\*(R" after the
+fork.
+.PP
+The default mode of operation (for libev, with application help to detect
+forks) is to duplicate all the state in the child, as would be expected
+when \fIeither\fR the parent \fIor\fR the child process continues.
+.PP
+When both processes want to continue using libev, then this is usually the
+wrong result. In that case, usually one process (typically the parent) is
+supposed to continue with all watchers in place as before, while the other
+process typically wants to start fresh, i.e. without any active watchers.
+.PP
+The cleanest and most efficient way to achieve that with libev is to
+simply create a new event loop, which of course will be \*(L"empty\*(R", and
+use that for new watchers. This has the advantage of not touching more
+memory than necessary, and thus avoiding the copy-on-write, and the
+disadvantage of having to use multiple event loops (which do not support
+signal watchers).
+.PP
+When this is not possible, or you want to use the default loop for
+other reasons, then in the process that wants to start \*(L"fresh\*(R", call
+\&\f(CW\*(C`ev_loop_destroy (EV_DEFAULT)\*(C'\fR followed by \f(CW\*(C`ev_default_loop (...)\*(C'\fR.
+Destroying the default loop will \*(L"orphan\*(R" (not stop) all registered
+watchers, so you have to be careful not to execute code that modifies
+those watchers. Note also that in that case, you have to re-register any
+signal watchers.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_fork_init (ev_fork *, callback)" 4
+.IX Item "ev_fork_init (ev_fork *, callback)"
+Initialises and configures the fork watcher \- it has no parameters of any
+kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless,
+really.
+.ie n .SS """ev_cleanup"" \- even the best things end"
+.el .SS "\f(CWev_cleanup\fP \- even the best things end"
+.IX Subsection "ev_cleanup - even the best things end"
+Cleanup watchers are called just before the event loop is being destroyed
+by a call to \f(CW\*(C`ev_loop_destroy\*(C'\fR.
+.PP
+While there is no guarantee that the event loop gets destroyed, cleanup
+watchers provide a convenient method to install cleanup hooks for your
+program, worker threads and so on \- you just to make sure to destroy the
+loop when you want them to be invoked.
+.PP
+Cleanup watchers are invoked in the same way as any other watcher. Unlike
+all other watchers, they do not keep a reference to the event loop (which
+makes a lot of sense if you think about it). Like all other watchers, you
+can call libev functions in the callback, except \f(CW\*(C`ev_cleanup_start\*(C'\fR.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_cleanup_init (ev_cleanup *, callback)" 4
+.IX Item "ev_cleanup_init (ev_cleanup *, callback)"
+Initialises and configures the cleanup watcher \- it has no parameters of
+any kind. There is a \f(CW\*(C`ev_cleanup_set\*(C'\fR macro, but using it is utterly
+pointless, I assure you.
+.PP
+Example: Register an atexit handler to destroy the default loop, so any
+cleanup functions are called.
+.PP
+.Vb 5
+\& static void
+\& program_exits (void)
+\& {
+\& ev_loop_destroy (EV_DEFAULT_UC);
+\& }
+\&
+\& ...
+\& atexit (program_exits);
+.Ve
+.ie n .SS """ev_async"" \- how to wake up an event loop"
+.el .SS "\f(CWev_async\fP \- how to wake up an event loop"
+.IX Subsection "ev_async - how to wake up an event loop"
+In general, you cannot use an \f(CW\*(C`ev_loop\*(C'\fR from multiple threads or other
+asynchronous sources such as signal handlers (as opposed to multiple event
+loops \- those are of course safe to use in different threads).
+.PP
+Sometimes, however, you need to wake up an event loop you do not control,
+for example because it belongs to another thread. This is what \f(CW\*(C`ev_async\*(C'\fR
+watchers do: as long as the \f(CW\*(C`ev_async\*(C'\fR watcher is active, you can signal
+it by calling \f(CW\*(C`ev_async_send\*(C'\fR, which is thread\- and signal safe.
+.PP
+This functionality is very similar to \f(CW\*(C`ev_signal\*(C'\fR watchers, as signals,
+too, are asynchronous in nature, and signals, too, will be compressed
+(i.e. the number of callback invocations may be less than the number of
+\&\f(CW\*(C`ev_async_send\*(C'\fR calls). In fact, you could use signal watchers as a kind
+of \*(L"global async watchers\*(R" by using a watcher on an otherwise unused
+signal, and \f(CW\*(C`ev_feed_signal\*(C'\fR to signal this watcher from another thread,
+even without knowing which loop owns the signal.
+.PP
+\fIQueueing\fR
+.IX Subsection "Queueing"
+.PP
+\&\f(CW\*(C`ev_async\*(C'\fR does not support queueing of data in any way. The reason
+is that the author does not know of a simple (or any) algorithm for a
+multiple-writer-single-reader queue that works in all cases and doesn't
+need elaborate support such as pthreads or unportable memory access
+semantics.
+.PP
+That means that if you want to queue data, you have to provide your own
+queue. But at least I can tell you how to implement locking around your
+queue:
+.IP "queueing from a signal handler context" 4
+.IX Item "queueing from a signal handler context"
+To implement race-free queueing, you simply add to the queue in the signal
+handler but you block the signal handler in the watcher callback. Here is
+an example that does that for some fictitious \s-1SIGUSR1\s0 handler:
+.Sp
+.Vb 1
+\& static ev_async mysig;
+\&
+\& static void
+\& sigusr1_handler (void)
+\& {
+\& sometype data;
+\&
+\& // no locking etc.
+\& queue_put (data);
+\& ev_async_send (EV_DEFAULT_ &mysig);
+\& }
+\&
+\& static void
+\& mysig_cb (EV_P_ ev_async *w, int revents)
+\& {
+\& sometype data;
+\& sigset_t block, prev;
+\&
+\& sigemptyset (&block);
+\& sigaddset (&block, SIGUSR1);
+\& sigprocmask (SIG_BLOCK, &block, &prev);
+\&
+\& while (queue_get (&data))
+\& process (data);
+\&
+\& if (sigismember (&prev, SIGUSR1)
+\& sigprocmask (SIG_UNBLOCK, &block, 0);
+\& }
+.Ve
+.Sp
+(Note: pthreads in theory requires you to use \f(CW\*(C`pthread_setmask\*(C'\fR
+instead of \f(CW\*(C`sigprocmask\*(C'\fR when you use threads, but libev doesn't do it
+either...).
+.IP "queueing from a thread context" 4
+.IX Item "queueing from a thread context"
+The strategy for threads is different, as you cannot (easily) block
+threads but you can easily preempt them, so to queue safely you need to
+employ a traditional mutex lock, such as in this pthread example:
+.Sp
+.Vb 2
+\& static ev_async mysig;
+\& static pthread_mutex_t mymutex = PTHREAD_MUTEX_INITIALIZER;
+\&
+\& static void
+\& otherthread (void)
+\& {
+\& // only need to lock the actual queueing operation
+\& pthread_mutex_lock (&mymutex);
+\& queue_put (data);
+\& pthread_mutex_unlock (&mymutex);
+\&
+\& ev_async_send (EV_DEFAULT_ &mysig);
+\& }
+\&
+\& static void
+\& mysig_cb (EV_P_ ev_async *w, int revents)
+\& {
+\& pthread_mutex_lock (&mymutex);
+\&
+\& while (queue_get (&data))
+\& process (data);
+\&
+\& pthread_mutex_unlock (&mymutex);
+\& }
+.Ve
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_async_init (ev_async *, callback)" 4
+.IX Item "ev_async_init (ev_async *, callback)"
+Initialises and configures the async watcher \- it has no parameters of any
+kind. There is a \f(CW\*(C`ev_async_set\*(C'\fR macro, but using it is utterly pointless,
+trust me.
+.IP "ev_async_send (loop, ev_async *)" 4
+.IX Item "ev_async_send (loop, ev_async *)"
+Sends/signals/activates the given \f(CW\*(C`ev_async\*(C'\fR watcher, that is, feeds
+an \f(CW\*(C`EV_ASYNC\*(C'\fR event on the watcher into the event loop, and instantly
+returns.
+.Sp
+Unlike \f(CW\*(C`ev_feed_event\*(C'\fR, this call is safe to do from other threads,
+signal or similar contexts (see the discussion of \f(CW\*(C`EV_ATOMIC_T\*(C'\fR in the
+embedding section below on what exactly this means).
+.Sp
+Note that, as with other watchers in libev, multiple events might get
+compressed into a single callback invocation (another way to look at
+this is that \f(CW\*(C`ev_async\*(C'\fR watchers are level-triggered: they are set on
+\&\f(CW\*(C`ev_async_send\*(C'\fR, reset when the event loop detects that).
+.Sp
+This call incurs the overhead of at most one extra system call per event
+loop iteration, if the event loop is blocked, and no syscall at all if
+the event loop (or your program) is processing events. That means that
+repeated calls are basically free (there is no need to avoid calls for
+performance reasons) and that the overhead becomes smaller (typically
+zero) under load.
+.IP "bool = ev_async_pending (ev_async *)" 4
+.IX Item "bool = ev_async_pending (ev_async *)"
+Returns a non-zero value when \f(CW\*(C`ev_async_send\*(C'\fR has been called on the
+watcher but the event has not yet been processed (or even noted) by the
+event loop.
+.Sp
+\&\f(CW\*(C`ev_async_send\*(C'\fR sets a flag in the watcher and wakes up the loop. When
+the loop iterates next and checks for the watcher to have become active,
+it will reset the flag again. \f(CW\*(C`ev_async_pending\*(C'\fR can be used to very
+quickly check whether invoking the loop might be a good idea.
+.Sp
+Not that this does \fInot\fR check whether the watcher itself is pending,
+only whether it has been requested to make this watcher pending: there
+is a time window between the event loop checking and resetting the async
+notification, and the callback being invoked.
+.SH "OTHER FUNCTIONS"
+.IX Header "OTHER FUNCTIONS"
+There are some other functions of possible interest. Described. Here. Now.
+.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback, arg)" 4
+.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback, arg)"
+This function combines a simple timer and an I/O watcher, calls your
+callback on whichever event happens first and automatically stops both
+watchers. This is useful if you want to wait for a single event on an fd
+or timeout without having to allocate/configure/start/stop/free one or
+more watchers yourself.
+.Sp
+If \f(CW\*(C`fd\*(C'\fR is less than 0, then no I/O watcher will be started and the
+\&\f(CW\*(C`events\*(C'\fR argument is being ignored. Otherwise, an \f(CW\*(C`ev_io\*(C'\fR watcher for
+the given \f(CW\*(C`fd\*(C'\fR and \f(CW\*(C`events\*(C'\fR set will be created and started.
+.Sp
+If \f(CW\*(C`timeout\*(C'\fR is less than 0, then no timeout watcher will be
+started. Otherwise an \f(CW\*(C`ev_timer\*(C'\fR watcher with after = \f(CW\*(C`timeout\*(C'\fR (and
+repeat = 0) will be started. \f(CW0\fR is a valid timeout.
+.Sp
+The callback has the type \f(CW\*(C`void (*cb)(int revents, void *arg)\*(C'\fR and is
+passed an \f(CW\*(C`revents\*(C'\fR set like normal event callbacks (a combination of
+\&\f(CW\*(C`EV_ERROR\*(C'\fR, \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_TIMER\*(C'\fR) and the \f(CW\*(C`arg\*(C'\fR
+value passed to \f(CW\*(C`ev_once\*(C'\fR. Note that it is possible to receive \fIboth\fR
+a timeout and an io event at the same time \- you probably should give io
+events precedence.
+.Sp
+Example: wait up to ten seconds for data to appear on \s-1STDIN_FILENO.\s0
+.Sp
+.Vb 7
+\& static void stdin_ready (int revents, void *arg)
+\& {
+\& if (revents & EV_READ)
+\& /* stdin might have data for us, joy! */;
+\& else if (revents & EV_TIMER)
+\& /* doh, nothing entered */;
+\& }
+\&
+\& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
+.Ve
+.IP "ev_feed_fd_event (loop, int fd, int revents)" 4
+.IX Item "ev_feed_fd_event (loop, int fd, int revents)"
+Feed an event on the given fd, as if a file descriptor backend detected
+the given events.
+.IP "ev_feed_signal_event (loop, int signum)" 4
+.IX Item "ev_feed_signal_event (loop, int signum)"
+Feed an event as if the given signal occurred. See also \f(CW\*(C`ev_feed_signal\*(C'\fR,
+which is async-safe.
+.SH "COMMON OR USEFUL IDIOMS (OR BOTH)"
+.IX Header "COMMON OR USEFUL IDIOMS (OR BOTH)"
+This section explains some common idioms that are not immediately
+obvious. Note that examples are sprinkled over the whole manual, and this
+section only contains stuff that wouldn't fit anywhere else.
+.SS "\s-1ASSOCIATING CUSTOM DATA WITH A WATCHER\s0"
+.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"
+Each watcher has, by default, a \f(CW\*(C`void *data\*(C'\fR member that you can read
+or modify at any time: libev will completely ignore it. This can be used
+to associate arbitrary data with your watcher. If you need more data and
+don't want to allocate memory separately and store a pointer to it in that
+data member, you can also \*(L"subclass\*(R" the watcher type and provide your own
+data:
+.PP
+.Vb 7
+\& struct my_io
+\& {
+\& ev_io io;
+\& int otherfd;
+\& void *somedata;
+\& struct whatever *mostinteresting;
+\& };
+\&
+\& ...
+\& struct my_io w;
+\& ev_io_init (&w.io, my_cb, fd, EV_READ);
+.Ve
+.PP
+And since your callback will be called with a pointer to the watcher, you
+can cast it back to your own type:
+.PP
+.Vb 5
+\& static void my_cb (struct ev_loop *loop, ev_io *w_, int revents)
+\& {
+\& struct my_io *w = (struct my_io *)w_;
+\& ...
+\& }
+.Ve
+.PP
+More interesting and less C\-conformant ways of casting your callback
+function type instead have been omitted.
+.SS "\s-1BUILDING YOUR OWN COMPOSITE WATCHERS\s0"
+.IX Subsection "BUILDING YOUR OWN COMPOSITE WATCHERS"
+Another common scenario is to use some data structure with multiple
+embedded watchers, in effect creating your own watcher that combines
+multiple libev event sources into one \*(L"super-watcher\*(R":
+.PP
+.Vb 6
+\& struct my_biggy
+\& {
+\& int some_data;
+\& ev_timer t1;
+\& ev_timer t2;
+\& }
+.Ve
+.PP
+In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more
+complicated: Either you store the address of your \f(CW\*(C`my_biggy\*(C'\fR struct in
+the \f(CW\*(C`data\*(C'\fR member of the watcher (for woozies or \*(C+ coders), or you need
+to use some pointer arithmetic using \f(CW\*(C`offsetof\*(C'\fR inside your watchers (for
+real programmers):
+.PP
+.Vb 1
+\& #include <stddef.h>
+\&
+\& static void
+\& t1_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& struct my_biggy big = (struct my_biggy *)
+\& (((char *)w) \- offsetof (struct my_biggy, t1));
+\& }
+\&
+\& static void
+\& t2_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& struct my_biggy big = (struct my_biggy *)
+\& (((char *)w) \- offsetof (struct my_biggy, t2));
+\& }
+.Ve
+.SS "\s-1AVOIDING FINISHING BEFORE RETURNING\s0"
+.IX Subsection "AVOIDING FINISHING BEFORE RETURNING"
+Often you have structures like this in event-based programs:
+.PP
+.Vb 4
+\& callback ()
+\& {
+\& free (request);
+\& }
+\&
+\& request = start_new_request (..., callback);
+.Ve
+.PP
+The intent is to start some \*(L"lengthy\*(R" operation. The \f(CW\*(C`request\*(C'\fR could be
+used to cancel the operation, or do other things with it.
+.PP
+It's not uncommon to have code paths in \f(CW\*(C`start_new_request\*(C'\fR that
+immediately invoke the callback, for example, to report errors. Or you add
+some caching layer that finds that it can skip the lengthy aspects of the
+operation and simply invoke the callback with the result.
+.PP
+The problem here is that this will happen \fIbefore\fR \f(CW\*(C`start_new_request\*(C'\fR
+has returned, so \f(CW\*(C`request\*(C'\fR is not set.
+.PP
+Even if you pass the request by some safer means to the callback, you
+might want to do something to the request after starting it, such as
+canceling it, which probably isn't working so well when the callback has
+already been invoked.
+.PP
+A common way around all these issues is to make sure that
+\&\f(CW\*(C`start_new_request\*(C'\fR \fIalways\fR returns before the callback is invoked. If
+\&\f(CW\*(C`start_new_request\*(C'\fR immediately knows the result, it can artificially
+delay invoking the callback by using a \f(CW\*(C`prepare\*(C'\fR or \f(CW\*(C`idle\*(C'\fR watcher for
+example, or more sneakily, by reusing an existing (stopped) watcher and
+pushing it into the pending queue:
+.PP
+.Vb 2
+\& ev_set_cb (watcher, callback);
+\& ev_feed_event (EV_A_ watcher, 0);
+.Ve
+.PP
+This way, \f(CW\*(C`start_new_request\*(C'\fR can safely return before the callback is
+invoked, while not delaying callback invocation too much.
+.SS "\s-1MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS\s0"
+.IX Subsection "MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS"
+Often (especially in \s-1GUI\s0 toolkits) there are places where you have
+\&\fImodal\fR interaction, which is most easily implemented by recursively
+invoking \f(CW\*(C`ev_run\*(C'\fR.
+.PP
+This brings the problem of exiting \- a callback might want to finish the
+main \f(CW\*(C`ev_run\*(C'\fR call, but not the nested one (e.g. user clicked \*(L"Quit\*(R", but
+a modal \*(L"Are you sure?\*(R" dialog is still waiting), or just the nested one
+and not the main one (e.g. user clocked \*(L"Ok\*(R" in a modal dialog), or some
+other combination: In these cases, a simple \f(CW\*(C`ev_break\*(C'\fR will not work.
+.PP
+The solution is to maintain \*(L"break this loop\*(R" variable for each \f(CW\*(C`ev_run\*(C'\fR
+invocation, and use a loop around \f(CW\*(C`ev_run\*(C'\fR until the condition is
+triggered, using \f(CW\*(C`EVRUN_ONCE\*(C'\fR:
+.PP
+.Vb 2
+\& // main loop
+\& int exit_main_loop = 0;
+\&
+\& while (!exit_main_loop)
+\& ev_run (EV_DEFAULT_ EVRUN_ONCE);
+\&
+\& // in a modal watcher
+\& int exit_nested_loop = 0;
+\&
+\& while (!exit_nested_loop)
+\& ev_run (EV_A_ EVRUN_ONCE);
+.Ve
+.PP
+To exit from any of these loops, just set the corresponding exit variable:
+.PP
+.Vb 2
+\& // exit modal loop
+\& exit_nested_loop = 1;
+\&
+\& // exit main program, after modal loop is finished
+\& exit_main_loop = 1;
+\&
+\& // exit both
+\& exit_main_loop = exit_nested_loop = 1;
+.Ve
+.SS "\s-1THREAD LOCKING EXAMPLE\s0"
+.IX Subsection "THREAD LOCKING EXAMPLE"
+Here is a fictitious example of how to run an event loop in a different
+thread from where callbacks are being invoked and watchers are
+created/added/removed.
+.PP
+For a real-world example, see the \f(CW\*(C`EV::Loop::Async\*(C'\fR perl module,
+which uses exactly this technique (which is suited for many high-level
+languages).
+.PP
+The example uses a pthread mutex to protect the loop data, a condition
+variable to wait for callback invocations, an async watcher to notify the
+event loop thread and an unspecified mechanism to wake up the main thread.
+.PP
+First, you need to associate some data with the event loop:
+.PP
+.Vb 6
+\& typedef struct {
+\& mutex_t lock; /* global loop lock */
+\& ev_async async_w;
+\& thread_t tid;
+\& cond_t invoke_cv;
+\& } userdata;
+\&
+\& void prepare_loop (EV_P)
+\& {
+\& // for simplicity, we use a static userdata struct.
+\& static userdata u;
+\&
+\& ev_async_init (&u\->async_w, async_cb);
+\& ev_async_start (EV_A_ &u\->async_w);
+\&
+\& pthread_mutex_init (&u\->lock, 0);
+\& pthread_cond_init (&u\->invoke_cv, 0);
+\&
+\& // now associate this with the loop
+\& ev_set_userdata (EV_A_ u);
+\& ev_set_invoke_pending_cb (EV_A_ l_invoke);
+\& ev_set_loop_release_cb (EV_A_ l_release, l_acquire);
+\&
+\& // then create the thread running ev_run
+\& pthread_create (&u\->tid, 0, l_run, EV_A);
+\& }
+.Ve
+.PP
+The callback for the \f(CW\*(C`ev_async\*(C'\fR watcher does nothing: the watcher is used
+solely to wake up the event loop so it takes notice of any new watchers
+that might have been added:
+.PP
+.Vb 5
+\& static void
+\& async_cb (EV_P_ ev_async *w, int revents)
+\& {
+\& // just used for the side effects
+\& }
+.Ve
+.PP
+The \f(CW\*(C`l_release\*(C'\fR and \f(CW\*(C`l_acquire\*(C'\fR callbacks simply unlock/lock the mutex
+protecting the loop data, respectively.
+.PP
+.Vb 6
+\& static void
+\& l_release (EV_P)
+\& {
+\& userdata *u = ev_userdata (EV_A);
+\& pthread_mutex_unlock (&u\->lock);
+\& }
+\&
+\& static void
+\& l_acquire (EV_P)
+\& {
+\& userdata *u = ev_userdata (EV_A);
+\& pthread_mutex_lock (&u\->lock);
+\& }
+.Ve
+.PP
+The event loop thread first acquires the mutex, and then jumps straight
+into \f(CW\*(C`ev_run\*(C'\fR:
+.PP
+.Vb 4
+\& void *
+\& l_run (void *thr_arg)
+\& {
+\& struct ev_loop *loop = (struct ev_loop *)thr_arg;
+\&
+\& l_acquire (EV_A);
+\& pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
+\& ev_run (EV_A_ 0);
+\& l_release (EV_A);
+\&
+\& return 0;
+\& }
+.Ve
+.PP
+Instead of invoking all pending watchers, the \f(CW\*(C`l_invoke\*(C'\fR callback will
+signal the main thread via some unspecified mechanism (signals? pipe
+writes? \f(CW\*(C`Async::Interrupt\*(C'\fR?) and then waits until all pending watchers
+have been called (in a while loop because a) spurious wakeups are possible
+and b) skipping inter-thread-communication when there are no pending
+watchers is very beneficial):
+.PP
+.Vb 4
+\& static void
+\& l_invoke (EV_P)
+\& {
+\& userdata *u = ev_userdata (EV_A);
+\&
+\& while (ev_pending_count (EV_A))
+\& {
+\& wake_up_other_thread_in_some_magic_or_not_so_magic_way ();
+\& pthread_cond_wait (&u\->invoke_cv, &u\->lock);
+\& }
+\& }
+.Ve
+.PP
+Now, whenever the main thread gets told to invoke pending watchers, it
+will grab the lock, call \f(CW\*(C`ev_invoke_pending\*(C'\fR and then signal the loop
+thread to continue:
+.PP
+.Vb 4
+\& static void
+\& real_invoke_pending (EV_P)
+\& {
+\& userdata *u = ev_userdata (EV_A);
+\&
+\& pthread_mutex_lock (&u\->lock);
+\& ev_invoke_pending (EV_A);
+\& pthread_cond_signal (&u\->invoke_cv);
+\& pthread_mutex_unlock (&u\->lock);
+\& }
+.Ve
+.PP
+Whenever you want to start/stop a watcher or do other modifications to an
+event loop, you will now have to lock:
+.PP
+.Vb 2
+\& ev_timer timeout_watcher;
+\& userdata *u = ev_userdata (EV_A);
+\&
+\& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+\&
+\& pthread_mutex_lock (&u\->lock);
+\& ev_timer_start (EV_A_ &timeout_watcher);
+\& ev_async_send (EV_A_ &u\->async_w);
+\& pthread_mutex_unlock (&u\->lock);
+.Ve
+.PP
+Note that sending the \f(CW\*(C`ev_async\*(C'\fR watcher is required because otherwise
+an event loop currently blocking in the kernel will have no knowledge
+about the newly added timer. By waking up the loop it will pick up any new
+watchers in the next event loop iteration.
+.SS "\s-1THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS\s0"
+.IX Subsection "THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS"
+While the overhead of a callback that e.g. schedules a thread is small, it
+is still an overhead. If you embed libev, and your main usage is with some
+kind of threads or coroutines, you might want to customise libev so that
+doesn't need callbacks anymore.
+.PP
+Imagine you have coroutines that you can switch to using a function
+\&\f(CW\*(C`switch_to (coro)\*(C'\fR, that libev runs in a coroutine called \f(CW\*(C`libev_coro\*(C'\fR
+and that due to some magic, the currently active coroutine is stored in a
+global called \f(CW\*(C`current_coro\*(C'\fR. Then you can build your own \*(L"wait for libev
+event\*(R" primitive by changing \f(CW\*(C`EV_CB_DECLARE\*(C'\fR and \f(CW\*(C`EV_CB_INVOKE\*(C'\fR (note
+the differing \f(CW\*(C`;\*(C'\fR conventions):
+.PP
+.Vb 2
+\& #define EV_CB_DECLARE(type) struct my_coro *cb;
+\& #define EV_CB_INVOKE(watcher) switch_to ((watcher)\->cb)
+.Ve
+.PP
+That means instead of having a C callback function, you store the
+coroutine to switch to in each watcher, and instead of having libev call
+your callback, you instead have it switch to that coroutine.
+.PP
+A coroutine might now wait for an event with a function called
+\&\f(CW\*(C`wait_for_event\*(C'\fR. (the watcher needs to be started, as always, but it doesn't
+matter when, or whether the watcher is active or not when this function is
+called):
+.PP
+.Vb 6
+\& void
+\& wait_for_event (ev_watcher *w)
+\& {
+\& ev_set_cb (w, current_coro);
+\& switch_to (libev_coro);
+\& }
+.Ve
+.PP
+That basically suspends the coroutine inside \f(CW\*(C`wait_for_event\*(C'\fR and
+continues the libev coroutine, which, when appropriate, switches back to
+this or any other coroutine.
+.PP
+You can do similar tricks if you have, say, threads with an event queue \-
+instead of storing a coroutine, you store the queue object and instead of
+switching to a coroutine, you push the watcher onto the queue and notify
+any waiters.
+.PP
+To embed libev, see \*(L"\s-1EMBEDDING\*(R"\s0, but in short, it's easiest to create two
+files, \fImy_ev.h\fR and \fImy_ev.c\fR that include the respective libev files:
+.PP
+.Vb 4
+\& // my_ev.h
+\& #define EV_CB_DECLARE(type) struct my_coro *cb;
+\& #define EV_CB_INVOKE(watcher) switch_to ((watcher)\->cb)
+\& #include "../libev/ev.h"
+\&
+\& // my_ev.c
+\& #define EV_H "my_ev.h"
+\& #include "../libev/ev.c"
+.Ve
+.PP
+And then use \fImy_ev.h\fR when you would normally use \fIev.h\fR, and compile
+\&\fImy_ev.c\fR into your project. When properly specifying include paths, you
+can even use \fIev.h\fR as header file name directly.
+.SH "LIBEVENT EMULATION"
+.IX Header "LIBEVENT EMULATION"
+Libev offers a compatibility emulation layer for libevent. It cannot
+emulate the internals of libevent, so here are some usage hints:
+.IP "\(bu" 4
+Only the libevent\-1.4.1\-beta \s-1API\s0 is being emulated.
+.Sp
+This was the newest libevent version available when libev was implemented,
+and is still mostly unchanged in 2010.
+.IP "\(bu" 4
+Use it by including <event.h>, as usual.
+.IP "\(bu" 4
+The following members are fully supported: ev_base, ev_callback,
+ev_arg, ev_fd, ev_res, ev_events.
+.IP "\(bu" 4
+Avoid using ev_flags and the EVLIST_*\-macros, while it is
+maintained by libev, it does not work exactly the same way as in libevent (consider
+it a private \s-1API\s0).
+.IP "\(bu" 4
+Priorities are not currently supported. Initialising priorities
+will fail and all watchers will have the same priority, even though there
+is an ev_pri field.
+.IP "\(bu" 4
+In libevent, the last base created gets the signals, in libev, the
+base that registered the signal gets the signals.
+.IP "\(bu" 4
+Other members are not supported.
+.IP "\(bu" 4
+The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need
+to use the libev header file and library.
+.SH "\*(C+ SUPPORT"
+.IX Header " SUPPORT"
+.SS "C \s-1API\s0"
+.IX Subsection "C API"
+The normal C \s-1API\s0 should work fine when used from \*(C+: both ev.h and the
+libev sources can be compiled as \*(C+. Therefore, code that uses the C \s-1API\s0
+will work fine.
+.PP
+Proper exception specifications might have to be added to callbacks passed
+to libev: exceptions may be thrown only from watcher callbacks, all other
+callbacks (allocator, syserr, loop acquire/release and periodic reschedule
+callbacks) must not throw exceptions, and might need a \f(CW\*(C`noexcept\*(C'\fR
+specification. If you have code that needs to be compiled as both C and
+\&\*(C+ you can use the \f(CW\*(C`EV_NOEXCEPT\*(C'\fR macro for this:
+.PP
+.Vb 6
+\& static void
+\& fatal_error (const char *msg) EV_NOEXCEPT
+\& {
+\& perror (msg);
+\& abort ();
+\& }
+\&
+\& ...
+\& ev_set_syserr_cb (fatal_error);
+.Ve
+.PP
+The only \s-1API\s0 functions that can currently throw exceptions are \f(CW\*(C`ev_run\*(C'\fR,
+\&\f(CW\*(C`ev_invoke\*(C'\fR, \f(CW\*(C`ev_invoke_pending\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR (the latter
+because it runs cleanup watchers).
+.PP
+Throwing exceptions in watcher callbacks is only supported if libev itself
+is compiled with a \*(C+ compiler or your C and \*(C+ environments allow
+throwing exceptions through C libraries (most do).
+.SS "\*(C+ \s-1API\s0"
+.IX Subsection " API"
+Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow
+you to use some convenience methods to start/stop watchers and also change
+the callback model to a model using method callbacks on objects.
+.PP
+To use it,
+.PP
+.Vb 1
+\& #include <ev++.h>
+.Ve
+.PP
+This automatically includes \fIev.h\fR and puts all of its definitions (many
+of them macros) into the global namespace. All \*(C+ specific things are
+put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding
+options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR.
+.PP
+Care has been taken to keep the overhead low. The only data member the \*(C+
+classes add (compared to plain C\-style watchers) is the event loop pointer
+that the watcher is associated with (or no additional members at all if
+you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev).
+.PP
+Currently, functions, static and non-static member functions and classes
+with \f(CW\*(C`operator ()\*(C'\fR can be used as callbacks. Other types should be easy
+to add as long as they only need one additional pointer for context. If
+you need support for other types of functors please contact the author
+(preferably after implementing it).
+.PP
+For all this to work, your \*(C+ compiler either has to use the same calling
+conventions as your C compiler (for static member functions), or you have
+to embed libev and compile libev itself as \*(C+.
+.PP
+Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace:
+.ie n .IP """ev::READ"", ""ev::WRITE"" etc." 4
+.el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4
+.IX Item "ev::READ, ev::WRITE etc."
+These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc.
+macros from \fIev.h\fR.
+.ie n .IP """ev::tstamp"", ""ev::now""" 4
+.el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4
+.IX Item "ev::tstamp, ev::now"
+Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix.
+.ie n .IP """ev::io"", ""ev::timer"", ""ev::periodic"", ""ev::idle"", ""ev::sig"" etc." 4
+.el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4
+.IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc."
+For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of
+the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR
+which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro
+defined by many implementations.
+.Sp
+All of those classes have these methods:
+.RS 4
+.IP "ev::TYPE::TYPE ()" 4
+.IX Item "ev::TYPE::TYPE ()"
+.PD 0
+.IP "ev::TYPE::TYPE (loop)" 4
+.IX Item "ev::TYPE::TYPE (loop)"
+.IP "ev::TYPE::~TYPE" 4
+.IX Item "ev::TYPE::~TYPE"
+.PD
+The constructor (optionally) takes an event loop to associate the watcher
+with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR.
+.Sp
+The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the
+\&\f(CW\*(C`set\*(C'\fR method before starting it.
+.Sp
+It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR
+method to set a callback before you can start the watcher.
+.Sp
+(The reason why you have to use a method is a limitation in \*(C+ which does
+not allow explicit template arguments for constructors).
+.Sp
+The destructor automatically stops the watcher if it is active.
+.IP "w\->set<class, &class::method> (object *)" 4
+.IX Item "w->set<class, &class::method> (object *)"
+This method sets the callback method to call. The method has to have a
+signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as
+first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as
+parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher.
+.Sp
+This method synthesizes efficient thunking code to call your method from
+the C callback that libev requires. If your compiler can inline your
+callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and
+your compiler is good :), then the method will be fully inlined into the
+thunking function, making it as fast as a direct C callback.
+.Sp
+Example: simple class declaration and watcher initialisation
+.Sp
+.Vb 4
+\& struct myclass
+\& {
+\& void io_cb (ev::io &w, int revents) { }
+\& }
+\&
+\& myclass obj;
+\& ev::io iow;
+\& iow.set <myclass, &myclass::io_cb> (&obj);
+.Ve
+.IP "w\->set (object *)" 4
+.IX Item "w->set (object *)"
+This is a variation of a method callback \- leaving out the method to call
+will default the method to \f(CW\*(C`operator ()\*(C'\fR, which makes it possible to use
+functor objects without having to manually specify the \f(CW\*(C`operator ()\*(C'\fR all
+the time. Incidentally, you can then also leave out the template argument
+list.
+.Sp
+The \f(CW\*(C`operator ()\*(C'\fR method prototype must be \f(CW\*(C`void operator ()(watcher &w,
+int revents)\*(C'\fR.
+.Sp
+See the method\-\f(CW\*(C`set\*(C'\fR above for more details.
+.Sp
+Example: use a functor object as callback.
+.Sp
+.Vb 7
+\& struct myfunctor
+\& {
+\& void operator() (ev::io &w, int revents)
+\& {
+\& ...
+\& }
+\& }
+\&
+\& myfunctor f;
+\&
+\& ev::io w;
+\& w.set (&f);
+.Ve
+.IP "w\->set<function> (void *data = 0)" 4
+.IX Item "w->set<function> (void *data = 0)"
+Also sets a callback, but uses a static method or plain function as
+callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's
+\&\f(CW\*(C`data\*(C'\fR member and is free for you to use.
+.Sp
+The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR.
+.Sp
+See the method\-\f(CW\*(C`set\*(C'\fR above for more details.
+.Sp
+Example: Use a plain function as callback.
+.Sp
+.Vb 2
+\& static void io_cb (ev::io &w, int revents) { }
+\& iow.set <io_cb> ();
+.Ve
+.IP "w\->set (loop)" 4
+.IX Item "w->set (loop)"
+Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only
+do this when the watcher is inactive (and not pending either).
+.IP "w\->set ([arguments])" 4
+.IX Item "w->set ([arguments])"
+Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR (except for \f(CW\*(C`ev::embed\*(C'\fR watchers>),
+with the same arguments. Either this method or a suitable start method
+must be called at least once. Unlike the C counterpart, an active watcher
+gets automatically stopped and restarted when reconfiguring it with this
+method.
+.Sp
+For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid
+clashing with the \f(CW\*(C`set (loop)\*(C'\fR method.
+.Sp
+For \f(CW\*(C`ev::io\*(C'\fR watchers there is an additional \f(CW\*(C`set\*(C'\fR method that acepts a
+new event mask only, and internally calls \f(CW\*(C`ev_io_modfify\*(C'\fR.
+.IP "w\->start ()" 4
+.IX Item "w->start ()"
+Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the
+constructor already stores the event loop.
+.IP "w\->start ([arguments])" 4
+.IX Item "w->start ([arguments])"
+Instead of calling \f(CW\*(C`set\*(C'\fR and \f(CW\*(C`start\*(C'\fR methods separately, it is often
+convenient to wrap them in one call. Uses the same type of arguments as
+the configure \f(CW\*(C`set\*(C'\fR method of the watcher.
+.IP "w\->stop ()" 4
+.IX Item "w->stop ()"
+Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument.
+.ie n .IP "w\->again () (""ev::timer"", ""ev::periodic"" only)" 4
+.el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4
+.IX Item "w->again () (ev::timer, ev::periodic only)"
+For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding
+\&\f(CW\*(C`ev_TYPE_again\*(C'\fR function.
+.ie n .IP "w\->sweep () (""ev::embed"" only)" 4
+.el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4
+.IX Item "w->sweep () (ev::embed only)"
+Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR.
+.ie n .IP "w\->update () (""ev::stat"" only)" 4
+.el .IP "w\->update () (\f(CWev::stat\fR only)" 4
+.IX Item "w->update () (ev::stat only)"
+Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR.
+.RE
+.RS 4
+.RE
+.PP
+Example: Define a class with two I/O and idle watchers, start the I/O
+watchers in the constructor.
+.PP
+.Vb 5
+\& class myclass
+\& {
+\& ev::io io ; void io_cb (ev::io &w, int revents);
+\& ev::io io2 ; void io2_cb (ev::io &w, int revents);
+\& ev::idle idle; void idle_cb (ev::idle &w, int revents);
+\&
+\& myclass (int fd)
+\& {
+\& io .set <myclass, &myclass::io_cb > (this);
+\& io2 .set <myclass, &myclass::io2_cb > (this);
+\& idle.set <myclass, &myclass::idle_cb> (this);
+\&
+\& io.set (fd, ev::WRITE); // configure the watcher
+\& io.start (); // start it whenever convenient
+\&
+\& io2.start (fd, ev::READ); // set + start in one call
+\& }
+\& };
+.Ve
+.SH "OTHER LANGUAGE BINDINGS"
+.IX Header "OTHER LANGUAGE BINDINGS"
+Libev does not offer other language bindings itself, but bindings for a
+number of languages exist in the form of third-party packages. If you know
+any interesting language binding in addition to the ones listed here, drop
+me a note.
+.IP "Perl" 4
+.IX Item "Perl"
+The \s-1EV\s0 module implements the full libev \s-1API\s0 and is actually used to test
+libev. \s-1EV\s0 is developed together with libev. Apart from the \s-1EV\s0 core module,
+there are additional modules that implement libev-compatible interfaces
+to \f(CW\*(C`libadns\*(C'\fR (\f(CW\*(C`EV::ADNS\*(C'\fR, but \f(CW\*(C`AnyEvent::DNS\*(C'\fR is preferred nowadays),
+\&\f(CW\*(C`Net::SNMP\*(C'\fR (\f(CW\*(C`Net::SNMP::EV\*(C'\fR) and the \f(CW\*(C`libglib\*(C'\fR event core (\f(CW\*(C`Glib::EV\*(C'\fR
+and \f(CW\*(C`EV::Glib\*(C'\fR).
+.Sp
+It can be found and installed via \s-1CPAN,\s0 its homepage is at
+<http://software.schmorp.de/pkg/EV>.
+.IP "Python" 4
+.IX Item "Python"
+Python bindings can be found at <http://code.google.com/p/pyev/>. It
+seems to be quite complete and well-documented.
+.IP "Ruby" 4
+.IX Item "Ruby"
+Tony Arcieri has written a ruby extension that offers access to a subset
+of the libev \s-1API\s0 and adds file handle abstractions, asynchronous \s-1DNS\s0 and
+more on top of it. It can be found via gem servers. Its homepage is at
+<http://rev.rubyforge.org/>.
+.Sp
+Roger Pack reports that using the link order \f(CW\*(C`\-lws2_32 \-lmsvcrt\-ruby\-190\*(C'\fR
+makes rev work even on mingw.
+.IP "Haskell" 4
+.IX Item "Haskell"
+A haskell binding to libev is available at
+<http://hackage.haskell.org/cgi\-bin/hackage\-scripts/package/hlibev>.
+.IP "D" 4
+.IX Item "D"
+Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to
+be found at <http://www.llucax.com.ar/proj/ev.d/index.html>.
+.IP "Ocaml" 4
+.IX Item "Ocaml"
+Erkki Seppala has written Ocaml bindings for libev, to be found at
+<http://modeemi.cs.tut.fi/~flux/software/ocaml\-ev/>.
+.IP "Lua" 4
+.IX Item "Lua"
+Brian Maher has written a partial interface to libev for lua (at the
+time of this writing, only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at
+<http://github.com/brimworks/lua\-ev>.
+.IP "Javascript" 4
+.IX Item "Javascript"
+Node.js (<http://nodejs.org>) uses libev as the underlying event library.
+.IP "Others" 4
+.IX Item "Others"
+There are others, and I stopped counting.
+.SH "MACRO MAGIC"
+.IX Header "MACRO MAGIC"
+Libev can be compiled with a variety of options, the most fundamental
+of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most)
+functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument.
+.PP
+To make it easier to write programs that cope with either variant, the
+following macros are defined:
+.ie n .IP """EV_A"", ""EV_A_""" 4
+.el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4
+.IX Item "EV_A, EV_A_"
+This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev
+loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument,
+\&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example:
+.Sp
+.Vb 3
+\& ev_unref (EV_A);
+\& ev_timer_add (EV_A_ watcher);
+\& ev_run (EV_A_ 0);
+.Ve
+.Sp
+It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope,
+which is often provided by the following macro.
+.ie n .IP """EV_P"", ""EV_P_""" 4
+.el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4
+.IX Item "EV_P, EV_P_"
+This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev
+loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter,
+\&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example:
+.Sp
+.Vb 2
+\& // this is how ev_unref is being declared
+\& static void ev_unref (EV_P);
+\&
+\& // this is how you can declare your typical callback
+\& static void cb (EV_P_ ev_timer *w, int revents)
+.Ve
+.Sp
+It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite
+suitable for use with \f(CW\*(C`EV_A\*(C'\fR.
+.ie n .IP """EV_DEFAULT"", ""EV_DEFAULT_""" 4
+.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
+.IX Item "EV_DEFAULT, EV_DEFAULT_"
+Similar to the other two macros, this gives you the value of the default
+loop, if multiple loops are supported (\*(L"ev loop default\*(R"). The default loop
+will be initialised if it isn't already initialised.
+.Sp
+For non-multiplicity builds, these macros do nothing, so you always have
+to initialise the loop somewhere.
+.ie n .IP """EV_DEFAULT_UC"", ""EV_DEFAULT_UC_""" 4
+.el .IP "\f(CWEV_DEFAULT_UC\fR, \f(CWEV_DEFAULT_UC_\fR" 4
+.IX Item "EV_DEFAULT_UC, EV_DEFAULT_UC_"
+Usage identical to \f(CW\*(C`EV_DEFAULT\*(C'\fR and \f(CW\*(C`EV_DEFAULT_\*(C'\fR, but requires that the
+default loop has been initialised (\f(CW\*(C`UC\*(C'\fR == unchecked). Their behaviour
+is undefined when the default loop has not been initialised by a previous
+execution of \f(CW\*(C`EV_DEFAULT\*(C'\fR, \f(CW\*(C`EV_DEFAULT_\*(C'\fR or \f(CW\*(C`ev_default_init (...)\*(C'\fR.
+.Sp
+It is often prudent to use \f(CW\*(C`EV_DEFAULT\*(C'\fR when initialising the first
+watcher in a function but use \f(CW\*(C`EV_DEFAULT_UC\*(C'\fR afterwards.
+.PP
+Example: Declare and initialise a check watcher, utilising the above
+macros so it will work regardless of whether multiple loops are supported
+or not.
+.PP
+.Vb 5
+\& static void
+\& check_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& ev_check_stop (EV_A_ w);
+\& }
+\&
+\& ev_check check;
+\& ev_check_init (&check, check_cb);
+\& ev_check_start (EV_DEFAULT_ &check);
+\& ev_run (EV_DEFAULT_ 0);
+.Ve
+.SH "EMBEDDING"
+.IX Header "EMBEDDING"
+Libev can (and often is) directly embedded into host
+applications. Examples of applications that embed it include the Deliantra
+Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe)
+and rxvt-unicode.
+.PP
+The goal is to enable you to just copy the necessary files into your
+source directory without having to change even a single line in them, so
+you can easily upgrade by simply copying (or having a checked-out copy of
+libev somewhere in your source tree).
+.SS "\s-1FILESETS\s0"
+.IX Subsection "FILESETS"
+Depending on what features you need you need to include one or more sets of files
+in your application.
+.PP
+\fI\s-1CORE EVENT LOOP\s0\fR
+.IX Subsection "CORE EVENT LOOP"
+.PP
+To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual
+configuration (no autoconf):
+.PP
+.Vb 2
+\& #define EV_STANDALONE 1
+\& #include "ev.c"
+.Ve
+.PP
+This will automatically include \fIev.h\fR, too, and should be done in a
+single C source file only to provide the function implementations. To use
+it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best
+done by writing a wrapper around \fIev.h\fR that you can include instead and
+where you can put other configuration options):
+.PP
+.Vb 2
+\& #define EV_STANDALONE 1
+\& #include "ev.h"
+.Ve
+.PP
+Both header files and implementation files can be compiled with a \*(C+
+compiler (at least, that's a stated goal, and breakage will be treated
+as a bug).
+.PP
+You need the following files in your source tree, or in a directory
+in your include path (e.g. in libev/ when using \-Ilibev):
+.PP
+.Vb 4
+\& ev.h
+\& ev.c
+\& ev_vars.h
+\& ev_wrap.h
+\&
+\& ev_win32.c required on win32 platforms only
+\&
+\& ev_select.c only when select backend is enabled
+\& ev_poll.c only when poll backend is enabled
+\& ev_epoll.c only when the epoll backend is enabled
+\& ev_linuxaio.c only when the linux aio backend is enabled
+\& ev_iouring.c only when the linux io_uring backend is enabled
+\& ev_kqueue.c only when the kqueue backend is enabled
+\& ev_port.c only when the solaris port backend is enabled
+.Ve
+.PP
+\&\fIev.c\fR includes the backend files directly when enabled, so you only need
+to compile this single file.
+.PP
+\fI\s-1LIBEVENT COMPATIBILITY API\s0\fR
+.IX Subsection "LIBEVENT COMPATIBILITY API"
+.PP
+To include the libevent compatibility \s-1API,\s0 also include:
+.PP
+.Vb 1
+\& #include "event.c"
+.Ve
+.PP
+in the file including \fIev.c\fR, and:
+.PP
+.Vb 1
+\& #include "event.h"
+.Ve
+.PP
+in the files that want to use the libevent \s-1API.\s0 This also includes \fIev.h\fR.
+.PP
+You need the following additional files for this:
+.PP
+.Vb 2
+\& event.h
+\& event.c
+.Ve
+.PP
+\fI\s-1AUTOCONF SUPPORT\s0\fR
+.IX Subsection "AUTOCONF SUPPORT"
+.PP
+Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your configuration in
+whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your
+\&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then
+include \fIconfig.h\fR and configure itself accordingly.
+.PP
+For this of course you need the m4 file:
+.PP
+.Vb 1
+\& libev.m4
+.Ve
+.SS "\s-1PREPROCESSOR SYMBOLS/MACROS\s0"
+.IX Subsection "PREPROCESSOR SYMBOLS/MACROS"
+Libev can be configured via a variety of preprocessor symbols you have to
+define before including (or compiling) any of its files. The default in
+the absence of autoconf is documented for every option.
+.PP
+Symbols marked with \*(L"(h)\*(R" do not change the \s-1ABI,\s0 and can have different
+values when compiling libev vs. including \fIev.h\fR, so it is permissible
+to redefine them before including \fIev.h\fR without breaking compatibility
+to a compiled library. All other symbols change the \s-1ABI,\s0 which means all
+users of libev and the libev code itself must be compiled with compatible
+settings.
+.IP "\s-1EV_COMPAT3\s0 (h)" 4
+.IX Item "EV_COMPAT3 (h)"
+Backwards compatibility is a major concern for libev. This is why this
+release of libev comes with wrappers for the functions and symbols that
+have been renamed between libev version 3 and 4.
+.Sp
+You can disable these wrappers (to test compatibility with future
+versions) by defining \f(CW\*(C`EV_COMPAT3\*(C'\fR to \f(CW0\fR when compiling your
+sources. This has the additional advantage that you can drop the \f(CW\*(C`struct\*(C'\fR
+from \f(CW\*(C`struct ev_loop\*(C'\fR declarations, as libev will provide an \f(CW\*(C`ev_loop\*(C'\fR
+typedef in that case.
+.Sp
+In some future version, the default for \f(CW\*(C`EV_COMPAT3\*(C'\fR will become \f(CW0\fR,
+and in some even more future version the compatibility code will be
+removed completely.
+.IP "\s-1EV_STANDALONE\s0 (h)" 4
+.IX Item "EV_STANDALONE (h)"
+Must always be \f(CW1\fR if you do not use autoconf configuration, which
+keeps libev from including \fIconfig.h\fR, and it also defines dummy
+implementations for some libevent functions (such as logging, which is not
+supported). It will also not define any of the structs usually found in
+\&\fIevent.h\fR that are not directly supported by the libev core alone.
+.Sp
+In standalone mode, libev will still try to automatically deduce the
+configuration, but has to be more conservative.
+.IP "\s-1EV_USE_FLOOR\s0" 4
+.IX Item "EV_USE_FLOOR"
+If defined to be \f(CW1\fR, libev will use the \f(CW\*(C`floor ()\*(C'\fR function for its
+periodic reschedule calculations, otherwise libev will fall back on a
+portable (slower) implementation. If you enable this, you usually have to
+link against libm or something equivalent. Enabling this when the \f(CW\*(C`floor\*(C'\fR
+function is not available will fail, so the safe default is to not enable
+this.
+.IP "\s-1EV_USE_MONOTONIC\s0" 4
+.IX Item "EV_USE_MONOTONIC"
+If defined to be \f(CW1\fR, libev will try to detect the availability of the
+monotonic clock option at both compile time and runtime. Otherwise no
+use of the monotonic clock option will be attempted. If you enable this,
+you usually have to link against librt or something similar. Enabling it
+when the functionality isn't available is safe, though, although you have
+to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR
+function is hiding in (often \fI\-lrt\fR). See also \f(CW\*(C`EV_USE_CLOCK_SYSCALL\*(C'\fR.
+.IP "\s-1EV_USE_REALTIME\s0" 4
+.IX Item "EV_USE_REALTIME"
+If defined to be \f(CW1\fR, libev will try to detect the availability of the
+real-time clock option at compile time (and assume its availability
+at runtime if successful). Otherwise no use of the real-time clock
+option will be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR
+by \f(CW\*(C`clock_get (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect
+correctness. See the note about libraries in the description of
+\&\f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. Defaults to the opposite value of
+\&\f(CW\*(C`EV_USE_CLOCK_SYSCALL\*(C'\fR.
+.IP "\s-1EV_USE_CLOCK_SYSCALL\s0" 4
+.IX Item "EV_USE_CLOCK_SYSCALL"
+If defined to be \f(CW1\fR, libev will try to use a direct syscall instead
+of calling the system-provided \f(CW\*(C`clock_gettime\*(C'\fR function. This option
+exists because on GNU/Linux, \f(CW\*(C`clock_gettime\*(C'\fR is in \f(CW\*(C`librt\*(C'\fR, but \f(CW\*(C`librt\*(C'\fR
+unconditionally pulls in \f(CW\*(C`libpthread\*(C'\fR, slowing down single-threaded
+programs needlessly. Using a direct syscall is slightly slower (in
+theory), because no optimised vdso implementation can be used, but avoids
+the pthread dependency. Defaults to \f(CW1\fR on GNU/Linux with glibc 2.x or
+higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR).
+.IP "\s-1EV_USE_NANOSLEEP\s0" 4
+.IX Item "EV_USE_NANOSLEEP"
+If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available
+and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR.
+.IP "\s-1EV_USE_EVENTFD\s0" 4
+.IX Item "EV_USE_EVENTFD"
+If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is
+available and will probe for kernel support at runtime. This will improve
+\&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption.
+If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
+2.7 or newer, otherwise disabled.
+.IP "\s-1EV_USE_SIGNALFD\s0" 4
+.IX Item "EV_USE_SIGNALFD"
+If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`signalfd ()\*(C'\fR is
+available and will probe for kernel support at runtime. This enables
+the use of \s-1EVFLAG_SIGNALFD\s0 for faster and simpler signal handling. If
+undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
+2.7 or newer, otherwise disabled.
+.IP "\s-1EV_USE_TIMERFD\s0" 4
+.IX Item "EV_USE_TIMERFD"
+If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`timerfd ()\*(C'\fR is
+available and will probe for kernel support at runtime. This allows
+libev to detect time jumps accurately. If undefined, it will be enabled
+if the headers indicate GNU/Linux + Glibc 2.8 or newer and define
+\&\f(CW\*(C`TFD_TIMER_CANCEL_ON_SET\*(C'\fR, otherwise disabled.
+.IP "\s-1EV_USE_EVENTFD\s0" 4
+.IX Item "EV_USE_EVENTFD"
+If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is
+available and will probe for kernel support at runtime. This will improve
+\&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption.
+If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
+2.7 or newer, otherwise disabled.
+.IP "\s-1EV_USE_SELECT\s0" 4
+.IX Item "EV_USE_SELECT"
+If undefined or defined to be \f(CW1\fR, libev will compile in support for the
+\&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at auto-detection will be done: if no
+other method takes over, select will be it. Otherwise the select backend
+will not be compiled in.
+.IP "\s-1EV_SELECT_USE_FD_SET\s0" 4
+.IX Item "EV_SELECT_USE_FD_SET"
+If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR
+structure. This is useful if libev doesn't compile due to a missing
+\&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it mis-guesses the bitset layout
+on exotic systems. This usually limits the range of file descriptors to
+some low limit such as 1024 or might have other limitations (winsocket
+only allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation,
+configures the maximum size of the \f(CW\*(C`fd_set\*(C'\fR.
+.IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4
+.IX Item "EV_SELECT_IS_WINSOCKET"
+When defined to \f(CW1\fR, the select backend will assume that
+select/socket/connect etc. don't understand file descriptors but
+wants osf handles on win32 (this is the case when the select to
+be used is the winsock select). This means that it will call
+\&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise,
+it is assumed that all these functions actually work on fds, even
+on win32. Should not be defined on non\-win32 platforms.
+.IP "\s-1EV_FD_TO_WIN32_HANDLE\s0(fd)" 4
+.IX Item "EV_FD_TO_WIN32_HANDLE(fd)"
+If \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR is enabled, then libev needs a way to map
+file descriptors to socket handles. When not defining this symbol (the
+default), then libev will call \f(CW\*(C`_get_osfhandle\*(C'\fR, which is usually
+correct. In some cases, programs use their own file descriptor management,
+in which case they can provide this function to map fds to socket handles.
+.IP "\s-1EV_WIN32_HANDLE_TO_FD\s0(handle)" 4
+.IX Item "EV_WIN32_HANDLE_TO_FD(handle)"
+If \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR then libev maps handles to file descriptors
+using the standard \f(CW\*(C`_open_osfhandle\*(C'\fR function. For programs implementing
+their own fd to handle mapping, overwriting this function makes it easier
+to do so. This can be done by defining this macro to an appropriate value.
+.IP "\s-1EV_WIN32_CLOSE_FD\s0(fd)" 4
+.IX Item "EV_WIN32_CLOSE_FD(fd)"
+If programs implement their own fd to handle mapping on win32, then this
+macro can be used to override the \f(CW\*(C`close\*(C'\fR function, useful to unregister
+file descriptors again. Note that the replacement function has to close
+the underlying \s-1OS\s0 handle.
+.IP "\s-1EV_USE_WSASOCKET\s0" 4
+.IX Item "EV_USE_WSASOCKET"
+If defined to be \f(CW1\fR, libev will use \f(CW\*(C`WSASocket\*(C'\fR to create its internal
+communication socket, which works better in some environments. Otherwise,
+the normal \f(CW\*(C`socket\*(C'\fR function will be used, which works better in other
+environments.
+.IP "\s-1EV_USE_POLL\s0" 4
+.IX Item "EV_USE_POLL"
+If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2)
+backend. Otherwise it will be enabled on non\-win32 platforms. It
+takes precedence over select.
+.IP "\s-1EV_USE_EPOLL\s0" 4
+.IX Item "EV_USE_EPOLL"
+If defined to be \f(CW1\fR, libev will compile in support for the Linux
+\&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for GNU/Linux systems. If undefined, it will be enabled if the
+headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
+.IP "\s-1EV_USE_LINUXAIO\s0" 4
+.IX Item "EV_USE_LINUXAIO"
+If defined to be \f(CW1\fR, libev will compile in support for the Linux aio
+backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). If undefined, it will be
+enabled on linux, otherwise disabled.
+.IP "\s-1EV_USE_IOURING\s0" 4
+.IX Item "EV_USE_IOURING"
+If defined to be \f(CW1\fR, libev will compile in support for the Linux
+io_uring backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). Due to it's
+current limitations it has to be requested explicitly. If undefined, it
+will be enabled on linux, otherwise disabled.
+.IP "\s-1EV_USE_KQUEUE\s0" 4
+.IX Item "EV_USE_KQUEUE"
+If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style
+\&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only
+supports some types of fds correctly (the only platform we found that
+supports ptys for example was NetBSD), so kqueue might be compiled in, but
+not be used unless explicitly requested. The best way to use it is to find
+out whether kqueue supports your type of fd properly and use an embedded
+kqueue loop.
+.IP "\s-1EV_USE_PORT\s0" 4
+.IX Item "EV_USE_PORT"
+If defined to be \f(CW1\fR, libev will compile in support for the Solaris
+10 port style backend. Its availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for Solaris 10 systems.
+.IP "\s-1EV_USE_DEVPOLL\s0" 4
+.IX Item "EV_USE_DEVPOLL"
+Reserved for future expansion, works like the \s-1USE\s0 symbols above.
+.IP "\s-1EV_USE_INOTIFY\s0" 4
+.IX Item "EV_USE_INOTIFY"
+If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify
+interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will
+be detected at runtime. If undefined, it will be enabled if the headers
+indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
+.IP "\s-1EV_NO_SMP\s0" 4
+.IX Item "EV_NO_SMP"
+If defined to be \f(CW1\fR, libev will assume that memory is always coherent
+between threads, that is, threads can be used, but threads never run on
+different cpus (or different cpu cores). This reduces dependencies
+and makes libev faster.
+.IP "\s-1EV_NO_THREADS\s0" 4
+.IX Item "EV_NO_THREADS"
+If defined to be \f(CW1\fR, libev will assume that it will never be called from
+different threads (that includes signal handlers), which is a stronger
+assumption than \f(CW\*(C`EV_NO_SMP\*(C'\fR, above. This reduces dependencies and makes
+libev faster.
+.IP "\s-1EV_ATOMIC_T\s0" 4
+.IX Item "EV_ATOMIC_T"
+Libev requires an integer type (suitable for storing \f(CW0\fR or \f(CW1\fR) whose
+access is atomic with respect to other threads or signal contexts. No
+such type is easily found in the C language, so you can provide your own
+type that you know is safe for your purposes. It is used both for signal
+handler \*(L"locking\*(R" as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR
+watchers.
+.Sp
+In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR
+(from \fIsignal.h\fR), which is usually good enough on most platforms.
+.IP "\s-1EV_H\s0 (h)" 4
+.IX Item "EV_H (h)"
+The name of the \fIev.h\fR header file used to include it. The default if
+undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be
+used to virtually rename the \fIev.h\fR header file in case of conflicts.
+.IP "\s-1EV_CONFIG_H\s0 (h)" 4
+.IX Item "EV_CONFIG_H (h)"
+If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override
+\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to
+\&\f(CW\*(C`EV_H\*(C'\fR, above.
+.IP "\s-1EV_EVENT_H\s0 (h)" 4
+.IX Item "EV_EVENT_H (h)"
+Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea
+of how the \fIevent.h\fR header can be found, the default is \f(CW"event.h"\fR.
+.IP "\s-1EV_PROTOTYPES\s0 (h)" 4
+.IX Item "EV_PROTOTYPES (h)"
+If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function
+prototypes, but still define all the structs and other symbols. This is
+occasionally useful if you want to provide your own wrapper functions
+around libev functions.
+.IP "\s-1EV_MULTIPLICITY\s0" 4
+.IX Item "EV_MULTIPLICITY"
+If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
+will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create
+additional independent event loops. Otherwise there will be no support
+for multiple event loops and there is no first event loop pointer
+argument. Instead, all functions act on the single default loop.
+.Sp
+Note that \f(CW\*(C`EV_DEFAULT\*(C'\fR and \f(CW\*(C`EV_DEFAULT_\*(C'\fR will no longer provide a
+default loop when multiplicity is switched off \- you always have to
+initialise the loop manually in this case.
+.IP "\s-1EV_MINPRI\s0" 4
+.IX Item "EV_MINPRI"
+.PD 0
+.IP "\s-1EV_MAXPRI\s0" 4
+.IX Item "EV_MAXPRI"
+.PD
+The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to
+\&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can
+provide for more priorities by overriding those symbols (usually defined
+to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively).
+.Sp
+When doing priority-based operations, libev usually has to linearly search
+all the priorities, so having many of them (hundreds) uses a lot of space
+and time, so using the defaults of five priorities (\-2 .. +2) is usually
+fine.
+.Sp
+If your embedding application does not need any priorities, defining these
+both to \f(CW0\fR will save some memory and \s-1CPU.\s0
+.IP "\s-1EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE.\s0" 4
+.IX Item "EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE."
+If undefined or defined to be \f(CW1\fR (and the platform supports it), then
+the respective watcher type is supported. If defined to be \f(CW0\fR, then it
+is not. Disabling watcher types mainly saves code size.
+.IP "\s-1EV_FEATURES\s0" 4
+.IX Item "EV_FEATURES"
+If you need to shave off some kilobytes of code at the expense of some
+speed (but with the full \s-1API\s0), you can define this symbol to request
+certain subsets of functionality. The default is to enable all features
+that can be enabled on the platform.
+.Sp
+A typical way to use this symbol is to define it to \f(CW0\fR (or to a bitset
+with some broad features you want) and then selectively re-enable
+additional parts you want, for example if you want everything minimal,
+but multiple event loop support, async and child watchers and the poll
+backend, use this:
+.Sp
+.Vb 5
+\& #define EV_FEATURES 0
+\& #define EV_MULTIPLICITY 1
+\& #define EV_USE_POLL 1
+\& #define EV_CHILD_ENABLE 1
+\& #define EV_ASYNC_ENABLE 1
+.Ve
+.Sp
+The actual value is a bitset, it can be a combination of the following
+values (by default, all of these are enabled):
+.RS 4
+.ie n .IP "1 \- faster/larger code" 4
+.el .IP "\f(CW1\fR \- faster/larger code" 4
+.IX Item "1 - faster/larger code"
+Use larger code to speed up some operations.
+.Sp
+Currently this is used to override some inlining decisions (enlarging the
+code size by roughly 30% on amd64).
+.Sp
+When optimising for size, use of compiler flags such as \f(CW\*(C`\-Os\*(C'\fR with
+gcc is recommended, as well as \f(CW\*(C`\-DNDEBUG\*(C'\fR, as libev contains a number of
+assertions.
+.Sp
+The default is off when \f(CW\*(C`_\|_OPTIMIZE_SIZE_\|_\*(C'\fR is defined by your compiler
+(e.g. gcc with \f(CW\*(C`\-Os\*(C'\fR).
+.ie n .IP "2 \- faster/larger data structures" 4
+.el .IP "\f(CW2\fR \- faster/larger data structures" 4
+.IX Item "2 - faster/larger data structures"
+Replaces the small 2\-heap for timer management by a faster 4\-heap, larger
+hash table sizes and so on. This will usually further increase code size
+and can additionally have an effect on the size of data structures at
+runtime.
+.Sp
+The default is off when \f(CW\*(C`_\|_OPTIMIZE_SIZE_\|_\*(C'\fR is defined by your compiler
+(e.g. gcc with \f(CW\*(C`\-Os\*(C'\fR).
+.ie n .IP "4 \- full \s-1API\s0 configuration" 4
+.el .IP "\f(CW4\fR \- full \s-1API\s0 configuration" 4
+.IX Item "4 - full API configuration"
+This enables priorities (sets \f(CW\*(C`EV_MAXPRI\*(C'\fR=2 and \f(CW\*(C`EV_MINPRI\*(C'\fR=\-2), and
+enables multiplicity (\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR=1).
+.ie n .IP "8 \- full \s-1API\s0" 4
+.el .IP "\f(CW8\fR \- full \s-1API\s0" 4
+.IX Item "8 - full API"
+This enables a lot of the \*(L"lesser used\*(R" \s-1API\s0 functions. See \f(CW\*(C`ev.h\*(C'\fR for
+details on which parts of the \s-1API\s0 are still available without this
+feature, and do not complain if this subset changes over time.
+.ie n .IP "16 \- enable all optional watcher types" 4
+.el .IP "\f(CW16\fR \- enable all optional watcher types" 4
+.IX Item "16 - enable all optional watcher types"
+Enables all optional watcher types. If you want to selectively enable
+only some watcher types other than I/O and timers (e.g. prepare,
+embed, async, child...) you can enable them manually by defining
+\&\f(CW\*(C`EV_watchertype_ENABLE\*(C'\fR to \f(CW1\fR instead.
+.ie n .IP "32 \- enable all backends" 4
+.el .IP "\f(CW32\fR \- enable all backends" 4
+.IX Item "32 - enable all backends"
+This enables all backends \- without this feature, you need to enable at
+least one backend manually (\f(CW\*(C`EV_USE_SELECT\*(C'\fR is a good choice).
+.ie n .IP "64 \- enable OS-specific ""helper"" APIs" 4
+.el .IP "\f(CW64\fR \- enable OS-specific ``helper'' APIs" 4
+.IX Item "64 - enable OS-specific helper APIs"
+Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
+default.
+.RE
+.RS 4
+.Sp
+Compiling with \f(CW\*(C`gcc \-Os \-DEV_STANDALONE \-DEV_USE_EPOLL=1 \-DEV_FEATURES=0\*(C'\fR
+reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
+code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
+watchers, timers and monotonic clock support.
+.Sp
+With an intelligent-enough linker (gcc+binutils are intelligent enough
+when you use \f(CW\*(C`\-Wl,\-\-gc\-sections \-ffunction\-sections\*(C'\fR) functions unused by
+your program might be left out as well \- a binary starting a timer and an
+I/O watcher then might come out at only 5Kb.
+.RE
+.IP "\s-1EV_API_STATIC\s0" 4
+.IX Item "EV_API_STATIC"
+If this symbol is defined (by default it is not), then all identifiers
+will have static linkage. This means that libev will not export any
+identifiers, and you cannot link against libev anymore. This can be useful
+when you embed libev, only want to use libev functions in a single file,
+and do not want its identifiers to be visible.
+.Sp
+To use this, define \f(CW\*(C`EV_API_STATIC\*(C'\fR and include \fIev.c\fR in the file that
+wants to use libev.
+.Sp
+This option only works when libev is compiled with a C compiler, as \*(C+
+doesn't support the required declaration syntax.
+.IP "\s-1EV_AVOID_STDIO\s0" 4
+.IX Item "EV_AVOID_STDIO"
+If this is set to \f(CW1\fR at compiletime, then libev will avoid using stdio
+functions (printf, scanf, perror etc.). This will increase the code size
+somewhat, but if your program doesn't otherwise depend on stdio and your
+libc allows it, this avoids linking in the stdio library which is quite
+big.
+.Sp
+Note that error messages might become less precise when this option is
+enabled.
+.IP "\s-1EV_NSIG\s0" 4
+.IX Item "EV_NSIG"
+The highest supported signal number, +1 (or, the number of
+signals): Normally, libev tries to deduce the maximum number of signals
+automatically, but sometimes this fails, in which case it can be
+specified. Also, using a lower number than detected (\f(CW32\fR should be
+good for about any system in existence) can save some memory, as libev
+statically allocates some 12\-24 bytes per signal number.
+.IP "\s-1EV_PID_HASHSIZE\s0" 4
+.IX Item "EV_PID_HASHSIZE"
+\&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by
+pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_FEATURES\*(C'\fR disabled),
+usually more than enough. If you need to manage thousands of children you
+might want to increase this value (\fImust\fR be a power of two).
+.IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4
+.IX Item "EV_INOTIFY_HASHSIZE"
+\&\f(CW\*(C`ev_stat\*(C'\fR watchers use a small hash table to distribute workload by
+inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_FEATURES\*(C'\fR
+disabled), usually more than enough. If you need to manage thousands of
+\&\f(CW\*(C`ev_stat\*(C'\fR watchers you might want to increase this value (\fImust\fR be a
+power of two).
+.IP "\s-1EV_USE_4HEAP\s0" 4
+.IX Item "EV_USE_4HEAP"
+Heaps are not very cache-efficient. To improve the cache-efficiency of the
+timer and periodics heaps, libev uses a 4\-heap when this symbol is defined
+to \f(CW1\fR. The 4\-heap uses more complicated (longer) code but has noticeably
+faster performance with many (thousands) of watchers.
+.Sp
+The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it
+will be \f(CW0\fR.
+.IP "\s-1EV_HEAP_CACHE_AT\s0" 4
+.IX Item "EV_HEAP_CACHE_AT"
+Heaps are not very cache-efficient. To improve the cache-efficiency of the
+timer and periodics heaps, libev can cache the timestamp (\fIat\fR) within
+the heap structure (selected by defining \f(CW\*(C`EV_HEAP_CACHE_AT\*(C'\fR to \f(CW1\fR),
+which uses 8\-12 bytes more per watcher and a few hundred bytes more code,
+but avoids random read accesses on heap changes. This improves performance
+noticeably with many (hundreds) of watchers.
+.Sp
+The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it
+will be \f(CW0\fR.
+.IP "\s-1EV_VERIFY\s0" 4
+.IX Item "EV_VERIFY"
+Controls how much internal verification (see \f(CW\*(C`ev_verify ()\*(C'\fR) will
+be done: If set to \f(CW0\fR, no internal verification code will be compiled
+in. If set to \f(CW1\fR, then verification code will be compiled in, but not
+called. If set to \f(CW2\fR, then the internal verification code will be
+called once per loop, which can slow down libev. If set to \f(CW3\fR, then the
+verification code will be called very frequently, which will slow down
+libev considerably.
+.Sp
+Verification errors are reported via C's \f(CW\*(C`assert\*(C'\fR mechanism, so if you
+disable that (e.g. by defining \f(CW\*(C`NDEBUG\*(C'\fR) then no errors will be reported.
+.Sp
+The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it
+will be \f(CW0\fR.
+.IP "\s-1EV_COMMON\s0" 4
+.IX Item "EV_COMMON"
+By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining
+this macro to something else you can include more and other types of
+members. You have to define it each time you include one of the files,
+though, and it must be identical each time.
+.Sp
+For example, the perl \s-1EV\s0 module uses something like this:
+.Sp
+.Vb 3
+\& #define EV_COMMON \e
+\& SV *self; /* contains this struct */ \e
+\& SV *cb_sv, *fh /* note no trailing ";" */
+.Ve
+.IP "\s-1EV_CB_DECLARE\s0 (type)" 4
+.IX Item "EV_CB_DECLARE (type)"
+.PD 0
+.IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4
+.IX Item "EV_CB_INVOKE (watcher, revents)"
+.IP "ev_set_cb (ev, cb)" 4
+.IX Item "ev_set_cb (ev, cb)"
+.PD
+Can be used to change the callback member declaration in each watcher,
+and the way callbacks are invoked and set. Must expand to a struct member
+definition and a statement, respectively. See the \fIev.h\fR header file for
+their default definitions. One possible use for overriding these is to
+avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use
+method calls instead of plain function calls in \*(C+.
+.SS "\s-1EXPORTED API SYMBOLS\s0"
+.IX Subsection "EXPORTED API SYMBOLS"
+If you need to re-export the \s-1API\s0 (e.g. via a \s-1DLL\s0) and you need a list of
+exported symbols, you can use the provided \fISymbol.*\fR files which list
+all public symbols, one per line:
+.PP
+.Vb 2
+\& Symbols.ev for libev proper
+\& Symbols.event for the libevent emulation
+.Ve
+.PP
+This can also be used to rename all public symbols to avoid clashes with
+multiple versions of libev linked together (which is obviously bad in
+itself, but sometimes it is inconvenient to avoid this).
+.PP
+A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to
+include before including \fIev.h\fR:
+.PP
+.Vb 1
+\& <Symbols.ev sed \-e "s/.*/#define & myprefix_&/" >wrap.h
+.Ve
+.PP
+This would create a file \fIwrap.h\fR which essentially looks like this:
+.PP
+.Vb 4
+\& #define ev_backend myprefix_ev_backend
+\& #define ev_check_start myprefix_ev_check_start
+\& #define ev_check_stop myprefix_ev_check_stop
+\& ...
+.Ve
+.SS "\s-1EXAMPLES\s0"
+.IX Subsection "EXAMPLES"
+For a real-world example of a program the includes libev
+verbatim, you can have a look at the \s-1EV\s0 perl module
+(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
+the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public
+interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file
+will be compiled. It is pretty complex because it provides its own header
+file.
+.PP
+The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
+that everybody includes and which overrides some configure choices:
+.PP
+.Vb 8
+\& #define EV_FEATURES 8
+\& #define EV_USE_SELECT 1
+\& #define EV_PREPARE_ENABLE 1
+\& #define EV_IDLE_ENABLE 1
+\& #define EV_SIGNAL_ENABLE 1
+\& #define EV_CHILD_ENABLE 1
+\& #define EV_USE_STDEXCEPT 0
+\& #define EV_CONFIG_H <config.h>
+\&
+\& #include "ev++.h"
+.Ve
+.PP
+And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled:
+.PP
+.Vb 2
+\& #include "ev_cpp.h"
+\& #include "ev.c"
+.Ve
+.SH "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT"
+.IX Header "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT"
+.SS "\s-1THREADS AND COROUTINES\s0"
+.IX Subsection "THREADS AND COROUTINES"
+\fI\s-1THREADS\s0\fR
+.IX Subsection "THREADS"
+.PP
+All libev functions are reentrant and thread-safe unless explicitly
+documented otherwise, but libev implements no locking itself. This means
+that you can use as many loops as you want in parallel, as long as there
+are no concurrent calls into any libev function with the same loop
+parameter (\f(CW\*(C`ev_default_*\*(C'\fR calls have an implicit default loop parameter,
+of course): libev guarantees that different event loops share no data
+structures that need any locking.
+.PP
+Or to put it differently: calls with different loop parameters can be done
+concurrently from multiple threads, calls with the same loop parameter
+must be done serially (but can be done from different threads, as long as
+only one thread ever is inside a call at any point in time, e.g. by using
+a mutex per loop).
+.PP
+Specifically to support threads (and signal handlers), libev implements
+so-called \f(CW\*(C`ev_async\*(C'\fR watchers, which allow some limited form of
+concurrency on the same event loop, namely waking it up \*(L"from the
+outside\*(R".
+.PP
+If you want to know which design (one loop, locking, or multiple loops
+without or something else still) is best for your problem, then I cannot
+help you, but here is some generic advice:
+.IP "\(bu" 4
+most applications have a main thread: use the default libev loop
+in that thread, or create a separate thread running only the default loop.
+.Sp
+This helps integrating other libraries or software modules that use libev
+themselves and don't care/know about threading.
+.IP "\(bu" 4
+one loop per thread is usually a good model.
+.Sp
+Doing this is almost never wrong, sometimes a better-performance model
+exists, but it is always a good start.
+.IP "\(bu" 4
+other models exist, such as the leader/follower pattern, where one
+loop is handed through multiple threads in a kind of round-robin fashion.
+.Sp
+Choosing a model is hard \- look around, learn, know that usually you can do
+better than you currently do :\-)
+.IP "\(bu" 4
+often you need to talk to some other thread which blocks in the
+event loop.
+.Sp
+\&\f(CW\*(C`ev_async\*(C'\fR watchers can be used to wake them up from other threads safely
+(or from signal contexts...).
+.Sp
+An example use would be to communicate signals or other events that only
+work in the default loop by registering the signal watcher with the
+default loop and triggering an \f(CW\*(C`ev_async\*(C'\fR watcher from the default loop
+watcher callback into the event loop interested in the signal.
+.PP
+See also \*(L"\s-1THREAD LOCKING EXAMPLE\*(R"\s0.
+.PP
+\fI\s-1COROUTINES\s0\fR
+.IX Subsection "COROUTINES"
+.PP
+Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"):
+libev fully supports nesting calls to its functions from different
+coroutines (e.g. you can call \f(CW\*(C`ev_run\*(C'\fR on the same loop from two
+different coroutines, and switch freely between both coroutines running
+the loop, as long as you don't confuse yourself). The only exception is
+that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks.
+.PP
+Care has been taken to ensure that libev does not keep local state inside
+\&\f(CW\*(C`ev_run\*(C'\fR, and other calls do not usually allow for coroutine switches as
+they do not call any callbacks.
+.SS "\s-1COMPILER WARNINGS\s0"
+.IX Subsection "COMPILER WARNINGS"
+Depending on your compiler and compiler settings, you might get no or a
+lot of warnings when compiling libev code. Some people are apparently
+scared by this.
+.PP
+However, these are unavoidable for many reasons. For one, each compiler
+has different warnings, and each user has different tastes regarding
+warning options. \*(L"Warn-free\*(R" code therefore cannot be a goal except when
+targeting a specific compiler and compiler-version.
+.PP
+Another reason is that some compiler warnings require elaborate
+workarounds, or other changes to the code that make it less clear and less
+maintainable.
+.PP
+And of course, some compiler warnings are just plain stupid, or simply
+wrong (because they don't actually warn about the condition their message
+seems to warn about). For example, certain older gcc versions had some
+warnings that resulted in an extreme number of false positives. These have
+been fixed, but some people still insist on making code warn-free with
+such buggy versions.
+.PP
+While libev is written to generate as few warnings as possible,
+\&\*(L"warn-free\*(R" code is not a goal, and it is recommended not to build libev
+with any compiler warnings enabled unless you are prepared to cope with
+them (e.g. by ignoring them). Remember that warnings are just that:
+warnings, not errors, or proof of bugs.
+.SS "\s-1VALGRIND\s0"
+.IX Subsection "VALGRIND"
+Valgrind has a special section here because it is a popular tool that is
+highly useful. Unfortunately, valgrind reports are very hard to interpret.
+.PP
+If you think you found a bug (memory leak, uninitialised data access etc.)
+in libev, then check twice: If valgrind reports something like:
+.PP
+.Vb 3
+\& ==2274== definitely lost: 0 bytes in 0 blocks.
+\& ==2274== possibly lost: 0 bytes in 0 blocks.
+\& ==2274== still reachable: 256 bytes in 1 blocks.
+.Ve
+.PP
+Then there is no memory leak, just as memory accounted to global variables
+is not a memleak \- the memory is still being referenced, and didn't leak.
+.PP
+Similarly, under some circumstances, valgrind might report kernel bugs
+as if it were a bug in libev (e.g. in realloc or in the poll backend,
+although an acceptable workaround has been found here), or it might be
+confused.
+.PP
+Keep in mind that valgrind is a very good tool, but only a tool. Don't
+make it into some kind of religion.
+.PP
+If you are unsure about something, feel free to contact the mailing list
+with the full valgrind report and an explanation on why you think this
+is a bug in libev (best check the archives, too :). However, don't be
+annoyed when you get a brisk \*(L"this is no bug\*(R" answer and take the chance
+of learning how to interpret valgrind properly.
+.PP
+If you need, for some reason, empty reports from valgrind for your project
+I suggest using suppression lists.
+.SH "PORTABILITY NOTES"
+.IX Header "PORTABILITY NOTES"
+.SS "\s-1GNU/LINUX 32 BIT LIMITATIONS\s0"
+.IX Subsection "GNU/LINUX 32 BIT LIMITATIONS"
+GNU/Linux is the only common platform that supports 64 bit file/large file
+interfaces but \fIdisables\fR them by default.
+.PP
+That means that libev compiled in the default environment doesn't support
+files larger than 2GiB or so, which mainly affects \f(CW\*(C`ev_stat\*(C'\fR watchers.
+.PP
+Unfortunately, many programs try to work around this GNU/Linux issue
+by enabling the large file \s-1API,\s0 which makes them incompatible with the
+standard libev compiled for their system.
+.PP
+Likewise, libev cannot enable the large file \s-1API\s0 itself as this would
+suddenly make it incompatible to the default compile time environment,
+i.e. all programs not using special compile switches.
+.SS "\s-1OS/X AND DARWIN BUGS\s0"
+.IX Subsection "OS/X AND DARWIN BUGS"
+The whole thing is a bug if you ask me \- basically any system interface
+you touch is broken, whether it is locales, poll, kqueue or even the
+OpenGL drivers.
+.PP
+\fI\f(CI\*(C`kqueue\*(C'\fI is buggy\fR
+.IX Subsection "kqueue is buggy"
+.PP
+The kqueue syscall is broken in all known versions \- most versions support
+only sockets, many support pipes.
+.PP
+Libev tries to work around this by not using \f(CW\*(C`kqueue\*(C'\fR by default on this
+rotten platform, but of course you can still ask for it when creating a
+loop \- embedding a socket-only kqueue loop into a select-based one is
+probably going to work well.
+.PP
+\fI\f(CI\*(C`poll\*(C'\fI is buggy\fR
+.IX Subsection "poll is buggy"
+.PP
+Instead of fixing \f(CW\*(C`kqueue\*(C'\fR, Apple replaced their (working) \f(CW\*(C`poll\*(C'\fR
+implementation by something calling \f(CW\*(C`kqueue\*(C'\fR internally around the 10.5.6
+release, so now \f(CW\*(C`kqueue\*(C'\fR \fIand\fR \f(CW\*(C`poll\*(C'\fR are broken.
+.PP
+Libev tries to work around this by not using \f(CW\*(C`poll\*(C'\fR by default on
+this rotten platform, but of course you can still ask for it when creating
+a loop.
+.PP
+\fI\f(CI\*(C`select\*(C'\fI is buggy\fR
+.IX Subsection "select is buggy"
+.PP
+All that's left is \f(CW\*(C`select\*(C'\fR, and of course Apple found a way to fuck this
+one up as well: On \s-1OS/X,\s0 \f(CW\*(C`select\*(C'\fR actively limits the number of file
+descriptors you can pass in to 1024 \- your program suddenly crashes when
+you use more.
+.PP
+There is an undocumented \*(L"workaround\*(R" for this \- defining
+\&\f(CW\*(C`_DARWIN_UNLIMITED_SELECT\*(C'\fR, which libev tries to use, so select \fIshould\fR
+work on \s-1OS/X.\s0
+.SS "\s-1SOLARIS PROBLEMS AND WORKAROUNDS\s0"
+.IX Subsection "SOLARIS PROBLEMS AND WORKAROUNDS"
+\fI\f(CI\*(C`errno\*(C'\fI reentrancy\fR
+.IX Subsection "errno reentrancy"
+.PP
+The default compile environment on Solaris is unfortunately so
+thread-unsafe that you can't even use components/libraries compiled
+without \f(CW\*(C`\-D_REENTRANT\*(C'\fR in a threaded program, which, of course, isn't
+defined by default. A valid, if stupid, implementation choice.
+.PP
+If you want to use libev in threaded environments you have to make sure
+it's compiled with \f(CW\*(C`_REENTRANT\*(C'\fR defined.
+.PP
+\fIEvent port backend\fR
+.IX Subsection "Event port backend"
+.PP
+The scalable event interface for Solaris is called \*(L"event
+ports\*(R". Unfortunately, this mechanism is very buggy in all major
+releases. If you run into high \s-1CPU\s0 usage, your program freezes or you get
+a large number of spurious wakeups, make sure you have all the relevant
+and latest kernel patches applied. No, I don't know which ones, but there
+are multiple ones to apply, and afterwards, event ports actually work
+great.
+.PP
+If you can't get it to work, you can try running the program by setting
+the environment variable \f(CW\*(C`LIBEV_FLAGS=3\*(C'\fR to only allow \f(CW\*(C`poll\*(C'\fR and
+\&\f(CW\*(C`select\*(C'\fR backends.
+.SS "\s-1AIX POLL BUG\s0"
+.IX Subsection "AIX POLL BUG"
+\&\s-1AIX\s0 unfortunately has a broken \f(CW\*(C`poll.h\*(C'\fR header. Libev works around
+this by trying to avoid the poll backend altogether (i.e. it's not even
+compiled in), which normally isn't a big problem as \f(CW\*(C`select\*(C'\fR works fine
+with large bitsets on \s-1AIX,\s0 and \s-1AIX\s0 is dead anyway.
+.SS "\s-1WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS\s0"
+.IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS"
+\fIGeneral issues\fR
+.IX Subsection "General issues"
+.PP
+Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev
+requires, and its I/O model is fundamentally incompatible with the \s-1POSIX\s0
+model. Libev still offers limited functionality on this platform in
+the form of the \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR backend, and only supports socket
+descriptors. This only applies when using Win32 natively, not when using
+e.g. cygwin. Actually, it only applies to the microsofts own compilers,
+as every compiler comes with a slightly differently broken/incompatible
+environment.
+.PP
+Lifting these limitations would basically require the full
+re-implementation of the I/O system. If you are into this kind of thing,
+then note that glib does exactly that for you in a very portable way (note
+also that glib is the slowest event library known to man).
+.PP
+There is no supported compilation method available on windows except
+embedding it into other applications.
+.PP
+Sensible signal handling is officially unsupported by Microsoft \- libev
+tries its best, but under most conditions, signals will simply not work.
+.PP
+Not a libev limitation but worth mentioning: windows apparently doesn't
+accept large writes: instead of resulting in a partial write, windows will
+either accept everything or return \f(CW\*(C`ENOBUFS\*(C'\fR if the buffer is too large,
+so make sure you only write small amounts into your sockets (less than a
+megabyte seems safe, but this apparently depends on the amount of memory
+available).
+.PP
+Due to the many, low, and arbitrary limits on the win32 platform and
+the abysmal performance of winsockets, using a large number of sockets
+is not recommended (and not reasonable). If your program needs to use
+more than a hundred or so sockets, then likely it needs to use a totally
+different implementation for windows, as libev offers the \s-1POSIX\s0 readiness
+notification model, which cannot be implemented efficiently on windows
+(due to Microsoft monopoly games).
+.PP
+A typical way to use libev under windows is to embed it (see the embedding
+section for details) and use the following \fIevwrap.h\fR header file instead
+of \fIev.h\fR:
+.PP
+.Vb 2
+\& #define EV_STANDALONE /* keeps ev from requiring config.h */
+\& #define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */
+\&
+\& #include "ev.h"
+.Ve
+.PP
+And compile the following \fIevwrap.c\fR file into your project (make sure
+you do \fInot\fR compile the \fIev.c\fR or any other embedded source files!):
+.PP
+.Vb 2
+\& #include "evwrap.h"
+\& #include "ev.c"
+.Ve
+.PP
+\fIThe winsocket \f(CI\*(C`select\*(C'\fI function\fR
+.IX Subsection "The winsocket select function"
+.PP
+The winsocket \f(CW\*(C`select\*(C'\fR function doesn't follow \s-1POSIX\s0 in that it
+requires socket \fIhandles\fR and not socket \fIfile descriptors\fR (it is
+also extremely buggy). This makes select very inefficient, and also
+requires a mapping from file descriptors to socket handles (the Microsoft
+C runtime provides the function \f(CW\*(C`_open_osfhandle\*(C'\fR for this). See the
+discussion of the \f(CW\*(C`EV_SELECT_USE_FD_SET\*(C'\fR, \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR and
+\&\f(CW\*(C`EV_FD_TO_WIN32_HANDLE\*(C'\fR preprocessor symbols for more info.
+.PP
+The configuration for a \*(L"naked\*(R" win32 using the Microsoft runtime
+libraries and raw winsocket select is:
+.PP
+.Vb 2
+\& #define EV_USE_SELECT 1
+\& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
+.Ve
+.PP
+Note that winsockets handling of fd sets is O(n), so you can easily get a
+complexity in the O(nX) range when using win32.
+.PP
+\fILimited number of file descriptors\fR
+.IX Subsection "Limited number of file descriptors"
+.PP
+Windows has numerous arbitrary (and low) limits on things.
+.PP
+Early versions of winsocket's select only supported waiting for a maximum
+of \f(CW64\fR handles (probably owning to the fact that all windows kernels
+can only wait for \f(CW64\fR things at the same time internally; Microsoft
+recommends spawning a chain of threads and wait for 63 handles and the
+previous thread in each. Sounds great!).
+.PP
+Newer versions support more handles, but you need to define \f(CW\*(C`FD_SETSIZE\*(C'\fR
+to some high number (e.g. \f(CW2048\fR) before compiling the winsocket select
+call (which might be in libev or elsewhere, for example, perl and many
+other interpreters do their own select emulation on windows).
+.PP
+Another limit is the number of file descriptors in the Microsoft runtime
+libraries, which by default is \f(CW64\fR (there must be a hidden \fI64\fR
+fetish or something like this inside Microsoft). You can increase this
+by calling \f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR
+(another arbitrary limit), but is broken in many versions of the Microsoft
+runtime libraries. This might get you to about \f(CW512\fR or \f(CW2048\fR sockets
+(depending on windows version and/or the phase of the moon). To get more,
+you need to wrap all I/O functions and provide your own fd management, but
+the cost of calling select (O(nX)) will likely make this unworkable.
+.SS "\s-1PORTABILITY REQUIREMENTS\s0"
+.IX Subsection "PORTABILITY REQUIREMENTS"
+In addition to a working ISO-C implementation and of course the
+backend-specific APIs, libev relies on a few additional extensions:
+.ie n .IP """void (*)(ev_watcher_type *, int revents)"" must have compatible calling conventions regardless of ""ev_watcher_type *""." 4
+.el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4
+.IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *."
+Libev assumes not only that all watcher pointers have the same internal
+structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO C\s0 for example), but it also
+assumes that the same (machine) code can be used to call any watcher
+callback: The watcher callbacks have different type signatures, but libev
+calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally.
+.IP "null pointers and integer zero are represented by 0 bytes" 4
+.IX Item "null pointers and integer zero are represented by 0 bytes"
+Libev uses \f(CW\*(C`memset\*(C'\fR to initialise structs and arrays to \f(CW0\fR bytes, and
+relies on this setting pointers and integers to null.
+.IP "pointer accesses must be thread-atomic" 4
+.IX Item "pointer accesses must be thread-atomic"
+Accessing a pointer value must be atomic, it must both be readable and
+writable in one piece \- this is the case on all current architectures.
+.ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4
+.el .IP "\f(CWsig_atomic_t volatile\fR must be thread-atomic as well" 4
+.IX Item "sig_atomic_t volatile must be thread-atomic as well"
+The type \f(CW\*(C`sig_atomic_t volatile\*(C'\fR (or whatever is defined as
+\&\f(CW\*(C`EV_ATOMIC_T\*(C'\fR) must be atomic with respect to accesses from different
+threads. This is not part of the specification for \f(CW\*(C`sig_atomic_t\*(C'\fR, but is
+believed to be sufficiently portable.
+.ie n .IP """sigprocmask"" must work in a threaded environment" 4
+.el .IP "\f(CWsigprocmask\fR must work in a threaded environment" 4
+.IX Item "sigprocmask must work in a threaded environment"
+Libev uses \f(CW\*(C`sigprocmask\*(C'\fR to temporarily block signals. This is not
+allowed in a threaded program (\f(CW\*(C`pthread_sigmask\*(C'\fR has to be used). Typical
+pthread implementations will either allow \f(CW\*(C`sigprocmask\*(C'\fR in the \*(L"main
+thread\*(R" or will block signals process-wide, both behaviours would
+be compatible with libev. Interaction between \f(CW\*(C`sigprocmask\*(C'\fR and
+\&\f(CW\*(C`pthread_sigmask\*(C'\fR could complicate things, however.
+.Sp
+The most portable way to handle signals is to block signals in all threads
+except the initial one, and run the signal handling loop in the initial
+thread as well.
+.ie n .IP """long"" must be large enough for common memory allocation sizes" 4
+.el .IP "\f(CWlong\fR must be large enough for common memory allocation sizes" 4
+.IX Item "long must be large enough for common memory allocation sizes"
+To improve portability and simplify its \s-1API,\s0 libev uses \f(CW\*(C`long\*(C'\fR internally
+instead of \f(CW\*(C`size_t\*(C'\fR when allocating its data structures. On non-POSIX
+systems (Microsoft...) this might be unexpectedly low, but is still at
+least 31 bits everywhere, which is enough for hundreds of millions of
+watchers.
+.ie n .IP """double"" must hold a time value in seconds with enough accuracy" 4
+.el .IP "\f(CWdouble\fR must hold a time value in seconds with enough accuracy" 4
+.IX Item "double must hold a time value in seconds with enough accuracy"
+The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to
+have at least 51 bits of mantissa (and 9 bits of exponent), which is
+good enough for at least into the year 4000 with millisecond accuracy
+(the design goal for libev). This requirement is overfulfilled by
+implementations using \s-1IEEE 754,\s0 which is basically all existing ones.
+.Sp
+With \s-1IEEE 754\s0 doubles, you get microsecond accuracy until at least the
+year 2255 (and millisecond accuracy till the year 287396 \- by then, libev
+is either obsolete or somebody patched it to use \f(CW\*(C`long double\*(C'\fR or
+something like that, just kidding).
+.PP
+If you know of other additional requirements drop me a note.
+.SH "ALGORITHMIC COMPLEXITIES"
+.IX Header "ALGORITHMIC COMPLEXITIES"
+In this section the complexities of (many of) the algorithms used inside
+libev will be documented. For complexity discussions about backends see
+the documentation for \f(CW\*(C`ev_default_init\*(C'\fR.
+.PP
+All of the following are about amortised time: If an array needs to be
+extended, libev needs to realloc and move the whole array, but this
+happens asymptotically rarer with higher number of elements, so O(1) might
+mean that libev does a lengthy realloc operation in rare cases, but on
+average it is much faster and asymptotically approaches constant time.
+.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
+.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
+This means that, when you have a watcher that triggers in one hour and
+there are 100 watchers that would trigger before that, then inserting will
+have to skip roughly seven (\f(CW\*(C`ld 100\*(C'\fR) of these watchers.
+.IP "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" 4
+.IX Item "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)"
+That means that changing a timer costs less than removing/adding them,
+as only the relative motion in the event queue has to be paid for.
+.IP "Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)" 4
+.IX Item "Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)"
+These just add the watcher into an array or at the head of a list.
+.IP "Stopping check/prepare/idle/fork/async watchers: O(1)" 4
+.IX Item "Stopping check/prepare/idle/fork/async watchers: O(1)"
+.PD 0
+.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4
+.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))"
+.PD
+These watchers are stored in lists, so they need to be walked to find the
+correct watcher to remove. The lists are usually short (you don't usually
+have many watchers waiting for the same fd or signal: one is typical, two
+is rare).
+.IP "Finding the next timer in each loop iteration: O(1)" 4
+.IX Item "Finding the next timer in each loop iteration: O(1)"
+By virtue of using a binary or 4\-heap, the next timer is always found at a
+fixed position in the storage array.
+.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
+.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
+A change means an I/O watcher gets started or stopped, which requires
+libev to recalculate its status (and possibly tell the kernel, depending
+on backend and whether \f(CW\*(C`ev_io_set\*(C'\fR was used).
+.IP "Activating one watcher (putting it into the pending state): O(1)" 4
+.IX Item "Activating one watcher (putting it into the pending state): O(1)"
+.PD 0
+.IP "Priority handling: O(number_of_priorities)" 4
+.IX Item "Priority handling: O(number_of_priorities)"
+.PD
+Priorities are implemented by allocating some space for each
+priority. When doing priority-based operations, libev usually has to
+linearly search all the priorities, but starting/stopping and activating
+watchers becomes O(1) with respect to priority handling.
+.IP "Sending an ev_async: O(1)" 4
+.IX Item "Sending an ev_async: O(1)"
+.PD 0
+.IP "Processing ev_async_send: O(number_of_async_watchers)" 4
+.IX Item "Processing ev_async_send: O(number_of_async_watchers)"
+.IP "Processing signals: O(max_signal_number)" 4
+.IX Item "Processing signals: O(max_signal_number)"
+.PD
+Sending involves a system call \fIiff\fR there were no other \f(CW\*(C`ev_async_send\*(C'\fR
+calls in the current loop iteration and the loop is currently
+blocked. Checking for async and signal events involves iterating over all
+running async watchers or all signal numbers.
+.SH "PORTING FROM LIBEV 3.X TO 4.X"
+.IX Header "PORTING FROM LIBEV 3.X TO 4.X"
+The major version 4 introduced some incompatible changes to the \s-1API.\s0
+.PP
+At the moment, the \f(CW\*(C`ev.h\*(C'\fR header file provides compatibility definitions
+for all changes, so most programs should still compile. The compatibility
+layer might be removed in later versions of libev, so better update to the
+new \s-1API\s0 early than late.
+.ie n .IP """EV_COMPAT3"" backwards compatibility mechanism" 4
+.el .IP "\f(CWEV_COMPAT3\fR backwards compatibility mechanism" 4
+.IX Item "EV_COMPAT3 backwards compatibility mechanism"
+The backward compatibility mechanism can be controlled by
+\&\f(CW\*(C`EV_COMPAT3\*(C'\fR. See \*(L"\s-1PREPROCESSOR SYMBOLS/MACROS\*(R"\s0 in the \*(L"\s-1EMBEDDING\*(R"\s0
+section.
+.ie n .IP """ev_default_destroy"" and ""ev_default_fork"" have been removed" 4
+.el .IP "\f(CWev_default_destroy\fR and \f(CWev_default_fork\fR have been removed" 4
+.IX Item "ev_default_destroy and ev_default_fork have been removed"
+These calls can be replaced easily by their \f(CW\*(C`ev_loop_xxx\*(C'\fR counterparts:
+.Sp
+.Vb 2
+\& ev_loop_destroy (EV_DEFAULT_UC);
+\& ev_loop_fork (EV_DEFAULT);
+.Ve
+.IP "function/symbol renames" 4
+.IX Item "function/symbol renames"
+A number of functions and symbols have been renamed:
+.Sp
+.Vb 3
+\& ev_loop => ev_run
+\& EVLOOP_NONBLOCK => EVRUN_NOWAIT
+\& EVLOOP_ONESHOT => EVRUN_ONCE
+\&
+\& ev_unloop => ev_break
+\& EVUNLOOP_CANCEL => EVBREAK_CANCEL
+\& EVUNLOOP_ONE => EVBREAK_ONE
+\& EVUNLOOP_ALL => EVBREAK_ALL
+\&
+\& EV_TIMEOUT => EV_TIMER
+\&
+\& ev_loop_count => ev_iteration
+\& ev_loop_depth => ev_depth
+\& ev_loop_verify => ev_verify
+.Ve
+.Sp
+Most functions working on \f(CW\*(C`struct ev_loop\*(C'\fR objects don't have an
+\&\f(CW\*(C`ev_loop_\*(C'\fR prefix, so it was removed; \f(CW\*(C`ev_loop\*(C'\fR, \f(CW\*(C`ev_unloop\*(C'\fR and
+associated constants have been renamed to not collide with the \f(CW\*(C`struct
+ev_loop\*(C'\fR anymore and \f(CW\*(C`EV_TIMER\*(C'\fR now follows the same naming scheme
+as all other watcher types. Note that \f(CW\*(C`ev_loop_fork\*(C'\fR is still called
+\&\f(CW\*(C`ev_loop_fork\*(C'\fR because it would otherwise clash with the \f(CW\*(C`ev_fork\*(C'\fR
+typedef.
+.ie n .IP """EV_MINIMAL"" mechanism replaced by ""EV_FEATURES""" 4
+.el .IP "\f(CWEV_MINIMAL\fR mechanism replaced by \f(CWEV_FEATURES\fR" 4
+.IX Item "EV_MINIMAL mechanism replaced by EV_FEATURES"
+The preprocessor symbol \f(CW\*(C`EV_MINIMAL\*(C'\fR has been replaced by a different
+mechanism, \f(CW\*(C`EV_FEATURES\*(C'\fR. Programs using \f(CW\*(C`EV_MINIMAL\*(C'\fR usually compile
+and work, but the library code will of course be larger.
+.SH "GLOSSARY"
+.IX Header "GLOSSARY"
+.IP "active" 4
+.IX Item "active"
+A watcher is active as long as it has been started and not yet stopped.
+See \*(L"\s-1WATCHER STATES\*(R"\s0 for details.
+.IP "application" 4
+.IX Item "application"
+In this document, an application is whatever is using libev.
+.IP "backend" 4
+.IX Item "backend"
+The part of the code dealing with the operating system interfaces.
+.IP "callback" 4
+.IX Item "callback"
+The address of a function that is called when some event has been
+detected. Callbacks are being passed the event loop, the watcher that
+received the event, and the actual event bitset.
+.IP "callback/watcher invocation" 4
+.IX Item "callback/watcher invocation"
+The act of calling the callback associated with a watcher.
+.IP "event" 4
+.IX Item "event"
+A change of state of some external event, such as data now being available
+for reading on a file descriptor, time having passed or simply not having
+any other events happening anymore.
+.Sp
+In libev, events are represented as single bits (such as \f(CW\*(C`EV_READ\*(C'\fR or
+\&\f(CW\*(C`EV_TIMER\*(C'\fR).
+.IP "event library" 4
+.IX Item "event library"
+A software package implementing an event model and loop.
+.IP "event loop" 4
+.IX Item "event loop"
+An entity that handles and processes external events and converts them
+into callback invocations.
+.IP "event model" 4
+.IX Item "event model"
+The model used to describe how an event loop handles and processes
+watchers and events.
+.IP "pending" 4
+.IX Item "pending"
+A watcher is pending as soon as the corresponding event has been
+detected. See \*(L"\s-1WATCHER STATES\*(R"\s0 for details.
+.IP "real time" 4
+.IX Item "real time"
+The physical time that is observed. It is apparently strictly monotonic :)
+.IP "wall-clock time" 4
+.IX Item "wall-clock time"
+The time and date as shown on clocks. Unlike real time, it can actually
+be wrong and jump forwards and backwards, e.g. when you adjust your
+clock.
+.IP "watcher" 4
+.IX Item "watcher"
+A data structure that describes interest in certain events. Watchers need
+to be started (attached to an event loop) before they can receive events.
+.SH "AUTHOR"
+.IX Header "AUTHOR"
+Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
+Magnusson and Emanuele Giaquinta, and minor corrections by many others.
diff --git a/3rdparty/libev/ev.c b/3rdparty/libev/ev.c
new file mode 100644
index 0000000..ec212a1
--- /dev/null
+++ b/3rdparty/libev/ev.c
@@ -0,0 +1,5627 @@
+/*
+ * libev event processing core, watcher management
+ *
+ * Copyright (c) 2007-2019 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+/* this big block deduces configuration from config.h */
+#ifndef EV_STANDALONE
+# ifdef EV_CONFIG_H
+# include EV_CONFIG_H
+# else
+# include "config.h"
+# endif
+
+# if HAVE_FLOOR
+# ifndef EV_USE_FLOOR
+# define EV_USE_FLOOR 1
+# endif
+# endif
+
+# if HAVE_CLOCK_SYSCALL
+# ifndef EV_USE_CLOCK_SYSCALL
+# define EV_USE_CLOCK_SYSCALL 1
+# ifndef EV_USE_REALTIME
+# define EV_USE_REALTIME 0
+# endif
+# ifndef EV_USE_MONOTONIC
+# define EV_USE_MONOTONIC 1
+# endif
+# endif
+# elif !defined EV_USE_CLOCK_SYSCALL
+# define EV_USE_CLOCK_SYSCALL 0
+# endif
+
+# if HAVE_CLOCK_GETTIME
+# ifndef EV_USE_MONOTONIC
+# define EV_USE_MONOTONIC 1
+# endif
+# ifndef EV_USE_REALTIME
+# define EV_USE_REALTIME 0
+# endif
+# else
+# ifndef EV_USE_MONOTONIC
+# define EV_USE_MONOTONIC 0
+# endif
+# ifndef EV_USE_REALTIME
+# define EV_USE_REALTIME 0
+# endif
+# endif
+
+# if HAVE_NANOSLEEP
+# ifndef EV_USE_NANOSLEEP
+# define EV_USE_NANOSLEEP EV_FEATURE_OS
+# endif
+# else
+# undef EV_USE_NANOSLEEP
+# define EV_USE_NANOSLEEP 0
+# endif
+
+# if HAVE_SELECT && HAVE_SYS_SELECT_H
+# ifndef EV_USE_SELECT
+# define EV_USE_SELECT EV_FEATURE_BACKENDS
+# endif
+# else
+# undef EV_USE_SELECT
+# define EV_USE_SELECT 0
+# endif
+
+# if HAVE_POLL && HAVE_POLL_H
+# ifndef EV_USE_POLL
+# define EV_USE_POLL EV_FEATURE_BACKENDS
+# endif
+# else
+# undef EV_USE_POLL
+# define EV_USE_POLL 0
+# endif
+
+# if HAVE_EPOLL_CTL && HAVE_SYS_EPOLL_H
+# ifndef EV_USE_EPOLL
+# define EV_USE_EPOLL EV_FEATURE_BACKENDS
+# endif
+# else
+# undef EV_USE_EPOLL
+# define EV_USE_EPOLL 0
+# endif
+
+# if HAVE_LINUX_AIO_ABI_H
+# ifndef EV_USE_LINUXAIO
+# define EV_USE_LINUXAIO 0 /* was: EV_FEATURE_BACKENDS, always off by default */
+# endif
+# else
+# undef EV_USE_LINUXAIO
+# define EV_USE_LINUXAIO 0
+# endif
+
+# if HAVE_LINUX_FS_H && HAVE_SYS_TIMERFD_H && HAVE_KERNEL_RWF_T
+# ifndef EV_USE_IOURING
+# define EV_USE_IOURING EV_FEATURE_BACKENDS
+# endif
+# else
+# undef EV_USE_IOURING
+# define EV_USE_IOURING 0
+# endif
+
+# if HAVE_KQUEUE && HAVE_SYS_EVENT_H
+# ifndef EV_USE_KQUEUE
+# define EV_USE_KQUEUE EV_FEATURE_BACKENDS
+# endif
+# else
+# undef EV_USE_KQUEUE
+# define EV_USE_KQUEUE 0
+# endif
+
+# if HAVE_PORT_H && HAVE_PORT_CREATE
+# ifndef EV_USE_PORT
+# define EV_USE_PORT EV_FEATURE_BACKENDS
+# endif
+# else
+# undef EV_USE_PORT
+# define EV_USE_PORT 0
+# endif
+
+# if HAVE_INOTIFY_INIT && HAVE_SYS_INOTIFY_H
+# ifndef EV_USE_INOTIFY
+# define EV_USE_INOTIFY EV_FEATURE_OS
+# endif
+# else
+# undef EV_USE_INOTIFY
+# define EV_USE_INOTIFY 0
+# endif
+
+# if HAVE_SIGNALFD && HAVE_SYS_SIGNALFD_H
+# ifndef EV_USE_SIGNALFD
+# define EV_USE_SIGNALFD EV_FEATURE_OS
+# endif
+# else
+# undef EV_USE_SIGNALFD
+# define EV_USE_SIGNALFD 0
+# endif
+
+# if HAVE_EVENTFD
+# ifndef EV_USE_EVENTFD
+# define EV_USE_EVENTFD EV_FEATURE_OS
+# endif
+# else
+# undef EV_USE_EVENTFD
+# define EV_USE_EVENTFD 0
+# endif
+
+# if HAVE_SYS_TIMERFD_H
+# ifndef EV_USE_TIMERFD
+# define EV_USE_TIMERFD EV_FEATURE_OS
+# endif
+# else
+# undef EV_USE_TIMERFD
+# define EV_USE_TIMERFD 0
+# endif
+
+#endif
+
+/* OS X, in its infinite idiocy, actually HARDCODES
+ * a limit of 1024 into their select. Where people have brains,
+ * OS X engineers apparently have a vacuum. Or maybe they were
+ * ordered to have a vacuum, or they do anything for money.
+ * This might help. Or not.
+ * Note that this must be defined early, as other include files
+ * will rely on this define as well.
+ */
+#define _DARWIN_UNLIMITED_SELECT 1
+
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <stddef.h>
+
+#include <stdio.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <time.h>
+#include <limits.h>
+
+#include <signal.h>
+
+#ifdef EV_H
+# include EV_H
+#else
+# include "ev.h"
+#endif
+
+#if EV_NO_THREADS
+# undef EV_NO_SMP
+# define EV_NO_SMP 1
+# undef ECB_NO_THREADS
+# define ECB_NO_THREADS 1
+#endif
+#if EV_NO_SMP
+# undef EV_NO_SMP
+# define ECB_NO_SMP 1
+#endif
+
+#ifndef _WIN32
+# include <sys/time.h>
+# include <sys/wait.h>
+# include <unistd.h>
+#else
+# include <io.h>
+# define WIN32_LEAN_AND_MEAN
+# include <winsock2.h>
+# include <windows.h>
+# ifndef EV_SELECT_IS_WINSOCKET
+# define EV_SELECT_IS_WINSOCKET 1
+# endif
+# undef EV_AVOID_STDIO
+#endif
+
+/* this block tries to deduce configuration from header-defined symbols and defaults */
+
+/* try to deduce the maximum number of signals on this platform */
+#if defined EV_NSIG
+/* use what's provided */
+#elif defined NSIG
+# define EV_NSIG (NSIG)
+#elif defined _NSIG
+# define EV_NSIG (_NSIG)
+#elif defined SIGMAX
+# define EV_NSIG (SIGMAX+1)
+#elif defined SIG_MAX
+# define EV_NSIG (SIG_MAX+1)
+#elif defined _SIG_MAX
+# define EV_NSIG (_SIG_MAX+1)
+#elif defined MAXSIG
+# define EV_NSIG (MAXSIG+1)
+#elif defined MAX_SIG
+# define EV_NSIG (MAX_SIG+1)
+#elif defined SIGARRAYSIZE
+# define EV_NSIG (SIGARRAYSIZE) /* Assume ary[SIGARRAYSIZE] */
+#elif defined _sys_nsig
+# define EV_NSIG (_sys_nsig) /* Solaris 2.5 */
+#else
+# define EV_NSIG (8 * sizeof (sigset_t) + 1)
+#endif
+
+#ifndef EV_USE_FLOOR
+# define EV_USE_FLOOR 0
+#endif
+
+#ifndef EV_USE_CLOCK_SYSCALL
+# if __linux && __GLIBC__ == 2 && __GLIBC_MINOR__ < 17
+# define EV_USE_CLOCK_SYSCALL EV_FEATURE_OS
+# else
+# define EV_USE_CLOCK_SYSCALL 0
+# endif
+#endif
+
+#if !(_POSIX_TIMERS > 0)
+# ifndef EV_USE_MONOTONIC
+# define EV_USE_MONOTONIC 0
+# endif
+# ifndef EV_USE_REALTIME
+# define EV_USE_REALTIME 0
+# endif
+#endif
+
+#ifndef EV_USE_MONOTONIC
+# if defined _POSIX_MONOTONIC_CLOCK && _POSIX_MONOTONIC_CLOCK >= 0
+# define EV_USE_MONOTONIC EV_FEATURE_OS
+# else
+# define EV_USE_MONOTONIC 0
+# endif
+#endif
+
+#ifndef EV_USE_REALTIME
+# define EV_USE_REALTIME !EV_USE_CLOCK_SYSCALL
+#endif
+
+#ifndef EV_USE_NANOSLEEP
+# if _POSIX_C_SOURCE >= 199309L
+# define EV_USE_NANOSLEEP EV_FEATURE_OS
+# else
+# define EV_USE_NANOSLEEP 0
+# endif
+#endif
+
+#ifndef EV_USE_SELECT
+# define EV_USE_SELECT EV_FEATURE_BACKENDS
+#endif
+
+#ifndef EV_USE_POLL
+# ifdef _WIN32
+# define EV_USE_POLL 0
+# else
+# define EV_USE_POLL EV_FEATURE_BACKENDS
+# endif
+#endif
+
+#ifndef EV_USE_EPOLL
+# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 4))
+# define EV_USE_EPOLL EV_FEATURE_BACKENDS
+# else
+# define EV_USE_EPOLL 0
+# endif
+#endif
+
+#ifndef EV_USE_KQUEUE
+# define EV_USE_KQUEUE 0
+#endif
+
+#ifndef EV_USE_PORT
+# define EV_USE_PORT 0
+#endif
+
+#ifndef EV_USE_LINUXAIO
+# if __linux /* libev currently assumes linux/aio_abi.h is always available on linux */
+# define EV_USE_LINUXAIO 0 /* was: 1, always off by default */
+# else
+# define EV_USE_LINUXAIO 0
+# endif
+#endif
+
+#ifndef EV_USE_IOURING
+# if __linux /* later checks might disable again */
+# define EV_USE_IOURING 1
+# else
+# define EV_USE_IOURING 0
+# endif
+#endif
+
+#ifndef EV_USE_INOTIFY
+# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 4))
+# define EV_USE_INOTIFY EV_FEATURE_OS
+# else
+# define EV_USE_INOTIFY 0
+# endif
+#endif
+
+#ifndef EV_PID_HASHSIZE
+# define EV_PID_HASHSIZE EV_FEATURE_DATA ? 16 : 1
+#endif
+
+#ifndef EV_INOTIFY_HASHSIZE
+# define EV_INOTIFY_HASHSIZE EV_FEATURE_DATA ? 16 : 1
+#endif
+
+#ifndef EV_USE_EVENTFD
+# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
+# define EV_USE_EVENTFD EV_FEATURE_OS
+# else
+# define EV_USE_EVENTFD 0
+# endif
+#endif
+
+#ifndef EV_USE_SIGNALFD
+# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
+# define EV_USE_SIGNALFD EV_FEATURE_OS
+# else
+# define EV_USE_SIGNALFD 0
+# endif
+#endif
+
+#ifndef EV_USE_TIMERFD
+# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 8))
+# define EV_USE_TIMERFD EV_FEATURE_OS
+# else
+# define EV_USE_TIMERFD 0
+# endif
+#endif
+
+#if 0 /* debugging */
+# define EV_VERIFY 3
+# define EV_USE_4HEAP 1
+# define EV_HEAP_CACHE_AT 1
+#endif
+
+#ifndef EV_VERIFY
+# define EV_VERIFY (EV_FEATURE_API ? 1 : 0)
+#endif
+
+#ifndef EV_USE_4HEAP
+# define EV_USE_4HEAP EV_FEATURE_DATA
+#endif
+
+#ifndef EV_HEAP_CACHE_AT
+# define EV_HEAP_CACHE_AT EV_FEATURE_DATA
+#endif
+
+#ifdef __ANDROID__
+/* supposedly, android doesn't typedef fd_mask */
+# undef EV_USE_SELECT
+# define EV_USE_SELECT 0
+/* supposedly, we need to include syscall.h, not sys/syscall.h, so just disable */
+# undef EV_USE_CLOCK_SYSCALL
+# define EV_USE_CLOCK_SYSCALL 0
+#endif
+
+/* aix's poll.h seems to cause lots of trouble */
+#ifdef _AIX
+/* AIX has a completely broken poll.h header */
+# undef EV_USE_POLL
+# define EV_USE_POLL 0
+#endif
+
+/* on linux, we can use a (slow) syscall to avoid a dependency on pthread, */
+/* which makes programs even slower. might work on other unices, too. */
+#if EV_USE_CLOCK_SYSCALL
+# include <sys/syscall.h>
+# ifdef SYS_clock_gettime
+# define clock_gettime(id, ts) syscall (SYS_clock_gettime, (id), (ts))
+# undef EV_USE_MONOTONIC
+# define EV_USE_MONOTONIC 1
+# define EV_NEED_SYSCALL 1
+# else
+# undef EV_USE_CLOCK_SYSCALL
+# define EV_USE_CLOCK_SYSCALL 0
+# endif
+#endif
+
+/* this block fixes any misconfiguration where we know we run into trouble otherwise */
+
+#ifndef CLOCK_MONOTONIC
+# undef EV_USE_MONOTONIC
+# define EV_USE_MONOTONIC 0
+#endif
+
+#ifndef CLOCK_REALTIME
+# undef EV_USE_REALTIME
+# define EV_USE_REALTIME 0
+#endif
+
+#if !EV_STAT_ENABLE
+# undef EV_USE_INOTIFY
+# define EV_USE_INOTIFY 0
+#endif
+
+#if __linux && EV_USE_IOURING
+# include <linux/version.h>
+# if LINUX_VERSION_CODE < KERNEL_VERSION(4,14,0)
+# undef EV_USE_IOURING
+# define EV_USE_IOURING 0
+# endif
+#endif
+
+#if !EV_USE_NANOSLEEP
+/* hp-ux has it in sys/time.h, which we unconditionally include above */
+# if !defined _WIN32 && !defined __hpux
+# include <sys/select.h>
+# endif
+#endif
+
+#if EV_USE_LINUXAIO
+# include <sys/syscall.h>
+# if SYS_io_getevents && EV_USE_EPOLL /* linuxaio backend requires epoll backend */
+# define EV_NEED_SYSCALL 1
+# else
+# undef EV_USE_LINUXAIO
+# define EV_USE_LINUXAIO 0
+# endif
+#endif
+
+#if EV_USE_IOURING
+# include <sys/syscall.h>
+# if !SYS_io_uring_setup && __linux && !__alpha
+# define SYS_io_uring_setup 425
+# define SYS_io_uring_enter 426
+# define SYS_io_uring_wregister 427
+# endif
+# if SYS_io_uring_setup && EV_USE_EPOLL /* iouring backend requires epoll backend */
+# define EV_NEED_SYSCALL 1
+# else
+# undef EV_USE_IOURING
+# define EV_USE_IOURING 0
+# endif
+#endif
+
+#if EV_USE_INOTIFY
+# include <sys/statfs.h>
+# include <sys/inotify.h>
+/* some very old inotify.h headers don't have IN_DONT_FOLLOW */
+# ifndef IN_DONT_FOLLOW
+# undef EV_USE_INOTIFY
+# define EV_USE_INOTIFY 0
+# endif
+#endif
+
+#if EV_USE_EVENTFD
+/* our minimum requirement is glibc 2.7 which has the stub, but not the full header */
+# include <stdint.h>
+# ifndef EFD_NONBLOCK
+# define EFD_NONBLOCK O_NONBLOCK
+# endif
+# ifndef EFD_CLOEXEC
+# ifdef O_CLOEXEC
+# define EFD_CLOEXEC O_CLOEXEC
+# else
+# define EFD_CLOEXEC 02000000
+# endif
+# endif
+EV_CPP(extern "C") int (eventfd) (unsigned int initval, int flags);
+#endif
+
+#if EV_USE_SIGNALFD
+/* our minimum requirement is glibc 2.7 which has the stub, but not the full header */
+# include <stdint.h>
+# ifndef SFD_NONBLOCK
+# define SFD_NONBLOCK O_NONBLOCK
+# endif
+# ifndef SFD_CLOEXEC
+# ifdef O_CLOEXEC
+# define SFD_CLOEXEC O_CLOEXEC
+# else
+# define SFD_CLOEXEC 02000000
+# endif
+# endif
+EV_CPP (extern "C") int (signalfd) (int fd, const sigset_t *mask, int flags);
+
+struct signalfd_siginfo
+{
+ uint32_t ssi_signo;
+ char pad[128 - sizeof (uint32_t)];
+};
+#endif
+
+/* for timerfd, libev core requires TFD_TIMER_CANCEL_ON_SET &c */
+#if EV_USE_TIMERFD
+# include <sys/timerfd.h>
+/* timerfd is only used for periodics */
+# if !(defined (TFD_TIMER_CANCEL_ON_SET) && defined (TFD_CLOEXEC) && defined (TFD_NONBLOCK)) || !EV_PERIODIC_ENABLE
+# undef EV_USE_TIMERFD
+# define EV_USE_TIMERFD 0
+# endif
+#endif
+
+/*****************************************************************************/
+
+#if EV_VERIFY >= 3
+# define EV_FREQUENT_CHECK ev_verify (EV_A)
+#else
+# define EV_FREQUENT_CHECK do { } while (0)
+#endif
+
+/*
+ * This is used to work around floating point rounding problems.
+ * This value is good at least till the year 4000.
+ */
+#define MIN_INTERVAL 0.0001220703125 /* 1/2**13, good till 4000 */
+/*#define MIN_INTERVAL 0.00000095367431640625 /* 1/2**20, good till 2200 */
+
+#define MIN_TIMEJUMP 1. /* minimum timejump that gets detected (if monotonic clock available) */
+#define MAX_BLOCKTIME 59.743 /* never wait longer than this time (to detect time jumps) */
+#define MAX_BLOCKTIME2 1500001.07 /* same, but when timerfd is used to detect jumps, also safe delay to not overflow */
+
+/* find a portable timestamp that is "always" in the future but fits into time_t.
+ * this is quite hard, and we are mostly guessing - we handle 32 bit signed/unsigned time_t,
+ * and sizes larger than 32 bit, and maybe the unlikely floating point time_t */
+#define EV_TSTAMP_HUGE \
+ (sizeof (time_t) >= 8 ? 10000000000000. \
+ : 0 < (time_t)4294967295 ? 4294967295. \
+ : 2147483647.) \
+
+#ifndef EV_TS_CONST
+# define EV_TS_CONST(nv) nv
+# define EV_TS_TO_MSEC(a) a * 1e3 + 0.9999
+# define EV_TS_FROM_USEC(us) us * 1e-6
+# define EV_TV_SET(tv,t) do { tv.tv_sec = (long)t; tv.tv_usec = (long)((t - tv.tv_sec) * 1e6); } while (0)
+# define EV_TS_SET(ts,t) do { ts.tv_sec = (long)t; ts.tv_nsec = (long)((t - ts.tv_sec) * 1e9); } while (0)
+# define EV_TV_GET(tv) ((tv).tv_sec + (tv).tv_usec * 1e-6)
+# define EV_TS_GET(ts) ((ts).tv_sec + (ts).tv_nsec * 1e-9)
+#endif
+
+/* the following is ecb.h embedded into libev - use update_ev_c to update from an external copy */
+/* ECB.H BEGIN */
+/*
+ * libecb - http://software.schmorp.de/pkg/libecb
+ *
+ * Copyright (©) 2009-2015,2018-2020 Marc Alexander Lehmann <libecb@schmorp.de>
+ * Copyright (©) 2011 Emanuele Giaquinta
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#ifndef ECB_H
+#define ECB_H
+
+/* 16 bits major, 16 bits minor */
+#define ECB_VERSION 0x00010008
+
+#include <string.h> /* for memcpy */
+
+#if defined (_WIN32) && !defined (__MINGW32__)
+ typedef signed char int8_t;
+ typedef unsigned char uint8_t;
+ typedef signed char int_fast8_t;
+ typedef unsigned char uint_fast8_t;
+ typedef signed short int16_t;
+ typedef unsigned short uint16_t;
+ typedef signed int int_fast16_t;
+ typedef unsigned int uint_fast16_t;
+ typedef signed int int32_t;
+ typedef unsigned int uint32_t;
+ typedef signed int int_fast32_t;
+ typedef unsigned int uint_fast32_t;
+ #if __GNUC__
+ typedef signed long long int64_t;
+ typedef unsigned long long uint64_t;
+ #else /* _MSC_VER || __BORLANDC__ */
+ typedef signed __int64 int64_t;
+ typedef unsigned __int64 uint64_t;
+ #endif
+ typedef int64_t int_fast64_t;
+ typedef uint64_t uint_fast64_t;
+ #ifdef _WIN64
+ #define ECB_PTRSIZE 8
+ typedef uint64_t uintptr_t;
+ typedef int64_t intptr_t;
+ #else
+ #define ECB_PTRSIZE 4
+ typedef uint32_t uintptr_t;
+ typedef int32_t intptr_t;
+ #endif
+#else
+ #include <inttypes.h>
+ #if (defined INTPTR_MAX ? INTPTR_MAX : ULONG_MAX) > 0xffffffffU
+ #define ECB_PTRSIZE 8
+ #else
+ #define ECB_PTRSIZE 4
+ #endif
+#endif
+
+#define ECB_GCC_AMD64 (__amd64 || __amd64__ || __x86_64 || __x86_64__)
+#define ECB_MSVC_AMD64 (_M_AMD64 || _M_X64)
+
+#ifndef ECB_OPTIMIZE_SIZE
+ #if __OPTIMIZE_SIZE__
+ #define ECB_OPTIMIZE_SIZE 1
+ #else
+ #define ECB_OPTIMIZE_SIZE 0
+ #endif
+#endif
+
+/* work around x32 idiocy by defining proper macros */
+#if ECB_GCC_AMD64 || ECB_MSVC_AMD64
+ #if _ILP32
+ #define ECB_AMD64_X32 1
+ #else
+ #define ECB_AMD64 1
+ #endif
+#endif
+
+/* many compilers define _GNUC_ to some versions but then only implement
+ * what their idiot authors think are the "more important" extensions,
+ * causing enormous grief in return for some better fake benchmark numbers.
+ * or so.
+ * we try to detect these and simply assume they are not gcc - if they have
+ * an issue with that they should have done it right in the first place.
+ */
+#if !defined __GNUC_MINOR__ || defined __INTEL_COMPILER || defined __SUNPRO_C || defined __SUNPRO_CC || defined __llvm__ || defined __clang__
+ #define ECB_GCC_VERSION(major,minor) 0
+#else
+ #define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
+#endif
+
+#define ECB_CLANG_VERSION(major,minor) (__clang_major__ > (major) || (__clang_major__ == (major) && __clang_minor__ >= (minor)))
+
+#if __clang__ && defined __has_builtin
+ #define ECB_CLANG_BUILTIN(x) __has_builtin (x)
+#else
+ #define ECB_CLANG_BUILTIN(x) 0
+#endif
+
+#if __clang__ && defined __has_extension
+ #define ECB_CLANG_EXTENSION(x) __has_extension (x)
+#else
+ #define ECB_CLANG_EXTENSION(x) 0
+#endif
+
+#define ECB_CPP (__cplusplus+0)
+#define ECB_CPP11 (__cplusplus >= 201103L)
+#define ECB_CPP14 (__cplusplus >= 201402L)
+#define ECB_CPP17 (__cplusplus >= 201703L)
+
+#if ECB_CPP
+ #define ECB_C 0
+ #define ECB_STDC_VERSION 0
+#else
+ #define ECB_C 1
+ #define ECB_STDC_VERSION __STDC_VERSION__
+#endif
+
+#define ECB_C99 (ECB_STDC_VERSION >= 199901L)
+#define ECB_C11 (ECB_STDC_VERSION >= 201112L)
+#define ECB_C17 (ECB_STDC_VERSION >= 201710L)
+
+#if ECB_CPP
+ #define ECB_EXTERN_C extern "C"
+ #define ECB_EXTERN_C_BEG ECB_EXTERN_C {
+ #define ECB_EXTERN_C_END }
+#else
+ #define ECB_EXTERN_C extern
+ #define ECB_EXTERN_C_BEG
+ #define ECB_EXTERN_C_END
+#endif
+
+/*****************************************************************************/
+
+/* ECB_NO_THREADS - ecb is not used by multiple threads, ever */
+/* ECB_NO_SMP - ecb might be used in multiple threads, but only on a single cpu */
+
+#if ECB_NO_THREADS
+ #define ECB_NO_SMP 1
+#endif
+
+#if ECB_NO_SMP
+ #define ECB_MEMORY_FENCE do { } while (0)
+#endif
+
+/* http://www-01.ibm.com/support/knowledgecenter/SSGH3R_13.1.0/com.ibm.xlcpp131.aix.doc/compiler_ref/compiler_builtins.html */
+#if __xlC__ && ECB_CPP
+ #include <builtins.h>
+#endif
+
+#if 1400 <= _MSC_VER
+ #include <intrin.h> /* fence functions _ReadBarrier, also bit search functions _BitScanReverse */
+#endif
+
+#ifndef ECB_MEMORY_FENCE
+ #if ECB_GCC_VERSION(2,5) || defined __INTEL_COMPILER || (__llvm__ && __GNUC__) || __SUNPRO_C >= 0x5110 || __SUNPRO_CC >= 0x5110
+ #define ECB_MEMORY_FENCE_RELAXED __asm__ __volatile__ ("" : : : "memory")
+ #if __i386 || __i386__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory")
+ #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("" : : : "memory")
+ #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("" : : : "memory")
+ #elif ECB_GCC_AMD64
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mfence" : : : "memory")
+ #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("" : : : "memory")
+ #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("" : : : "memory")
+ #elif __powerpc__ || __ppc__ || __powerpc64__ || __ppc64__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("sync" : : : "memory")
+ #elif defined __ARM_ARCH_2__ \
+ || defined __ARM_ARCH_3__ || defined __ARM_ARCH_3M__ \
+ || defined __ARM_ARCH_4__ || defined __ARM_ARCH_4T__ \
+ || defined __ARM_ARCH_5__ || defined __ARM_ARCH_5E__ \
+ || defined __ARM_ARCH_5T__ || defined __ARM_ARCH_5TE__ \
+ || defined __ARM_ARCH_5TEJ__
+ /* should not need any, unless running old code on newer cpu - arm doesn't support that */
+ #elif defined __ARM_ARCH_6__ || defined __ARM_ARCH_6J__ \
+ || defined __ARM_ARCH_6K__ || defined __ARM_ARCH_6ZK__ \
+ || defined __ARM_ARCH_6T2__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mcr p15,0,%0,c7,c10,5" : : "r" (0) : "memory")
+ #elif defined __ARM_ARCH_7__ || defined __ARM_ARCH_7A__ \
+ || defined __ARM_ARCH_7R__ || defined __ARM_ARCH_7M__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("dmb" : : : "memory")
+ #elif __aarch64__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("dmb ish" : : : "memory")
+ #elif (__sparc || __sparc__) && !(__sparc_v8__ || defined __sparcv8)
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("membar #LoadStore | #LoadLoad | #StoreStore | #StoreLoad" : : : "memory")
+ #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("membar #LoadStore | #LoadLoad" : : : "memory")
+ #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("membar #LoadStore | #StoreStore")
+ #elif defined __s390__ || defined __s390x__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("bcr 15,0" : : : "memory")
+ #elif defined __mips__
+ /* GNU/Linux emulates sync on mips1 architectures, so we force its use */
+ /* anybody else who still uses mips1 is supposed to send in their version, with detection code. */
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ (".set mips2; sync; .set mips0" : : : "memory")
+ #elif defined __alpha__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mb" : : : "memory")
+ #elif defined __hppa__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("" : : : "memory")
+ #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("")
+ #elif defined __ia64__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mf" : : : "memory")
+ #elif defined __m68k__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("" : : : "memory")
+ #elif defined __m88k__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("tb1 0,%%r0,128" : : : "memory")
+ #elif defined __sh__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("" : : : "memory")
+ #endif
+ #endif
+#endif
+
+#ifndef ECB_MEMORY_FENCE
+ #if ECB_GCC_VERSION(4,7)
+ /* see comment below (stdatomic.h) about the C11 memory model. */
+ #define ECB_MEMORY_FENCE __atomic_thread_fence (__ATOMIC_SEQ_CST)
+ #define ECB_MEMORY_FENCE_ACQUIRE __atomic_thread_fence (__ATOMIC_ACQUIRE)
+ #define ECB_MEMORY_FENCE_RELEASE __atomic_thread_fence (__ATOMIC_RELEASE)
+ #define ECB_MEMORY_FENCE_RELAXED __atomic_thread_fence (__ATOMIC_RELAXED)
+
+ #elif ECB_CLANG_EXTENSION(c_atomic)
+ /* see comment below (stdatomic.h) about the C11 memory model. */
+ #define ECB_MEMORY_FENCE __c11_atomic_thread_fence (__ATOMIC_SEQ_CST)
+ #define ECB_MEMORY_FENCE_ACQUIRE __c11_atomic_thread_fence (__ATOMIC_ACQUIRE)
+ #define ECB_MEMORY_FENCE_RELEASE __c11_atomic_thread_fence (__ATOMIC_RELEASE)
+ #define ECB_MEMORY_FENCE_RELAXED __c11_atomic_thread_fence (__ATOMIC_RELAXED)
+
+ #elif ECB_GCC_VERSION(4,4) || defined __INTEL_COMPILER || defined __clang__
+ #define ECB_MEMORY_FENCE __sync_synchronize ()
+ #elif _MSC_VER >= 1500 /* VC++ 2008 */
+ /* apparently, microsoft broke all the memory barrier stuff in Visual Studio 2008... */
+ #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier)
+ #define ECB_MEMORY_FENCE _ReadWriteBarrier (); MemoryBarrier()
+ #define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier (); MemoryBarrier() /* according to msdn, _ReadBarrier is not a load fence */
+ #define ECB_MEMORY_FENCE_RELEASE _WriteBarrier (); MemoryBarrier()
+ #elif _MSC_VER >= 1400 /* VC++ 2005 */
+ #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier)
+ #define ECB_MEMORY_FENCE _ReadWriteBarrier ()
+ #define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier () /* according to msdn, _ReadBarrier is not a load fence */
+ #define ECB_MEMORY_FENCE_RELEASE _WriteBarrier ()
+ #elif defined _WIN32
+ #include <WinNT.h>
+ #define ECB_MEMORY_FENCE MemoryBarrier () /* actually just xchg on x86... scary */
+ #elif __SUNPRO_C >= 0x5110 || __SUNPRO_CC >= 0x5110
+ #include <mbarrier.h>
+ #define ECB_MEMORY_FENCE __machine_rw_barrier ()
+ #define ECB_MEMORY_FENCE_ACQUIRE __machine_acq_barrier ()
+ #define ECB_MEMORY_FENCE_RELEASE __machine_rel_barrier ()
+ #define ECB_MEMORY_FENCE_RELAXED __compiler_barrier ()
+ #elif __xlC__
+ #define ECB_MEMORY_FENCE __sync ()
+ #endif
+#endif
+
+#ifndef ECB_MEMORY_FENCE
+ #if ECB_C11 && !defined __STDC_NO_ATOMICS__
+ /* we assume that these memory fences work on all variables/all memory accesses, */
+ /* not just C11 atomics and atomic accesses */
+ #include <stdatomic.h>
+ #define ECB_MEMORY_FENCE atomic_thread_fence (memory_order_seq_cst)
+ #define ECB_MEMORY_FENCE_ACQUIRE atomic_thread_fence (memory_order_acquire)
+ #define ECB_MEMORY_FENCE_RELEASE atomic_thread_fence (memory_order_release)
+ #endif
+#endif
+
+#ifndef ECB_MEMORY_FENCE
+ #if !ECB_AVOID_PTHREADS
+ /*
+ * if you get undefined symbol references to pthread_mutex_lock,
+ * or failure to find pthread.h, then you should implement
+ * the ECB_MEMORY_FENCE operations for your cpu/compiler
+ * OR provide pthread.h and link against the posix thread library
+ * of your system.
+ */
+ #include <pthread.h>
+ #define ECB_NEEDS_PTHREADS 1
+ #define ECB_MEMORY_FENCE_NEEDS_PTHREADS 1
+
+ static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER;
+ #define ECB_MEMORY_FENCE do { pthread_mutex_lock (&ecb_mf_lock); pthread_mutex_unlock (&ecb_mf_lock); } while (0)
+ #endif
+#endif
+
+#if !defined ECB_MEMORY_FENCE_ACQUIRE && defined ECB_MEMORY_FENCE
+ #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
+#endif
+
+#if !defined ECB_MEMORY_FENCE_RELEASE && defined ECB_MEMORY_FENCE
+ #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
+#endif
+
+#if !defined ECB_MEMORY_FENCE_RELAXED && defined ECB_MEMORY_FENCE
+ #define ECB_MEMORY_FENCE_RELAXED ECB_MEMORY_FENCE /* very heavy-handed */
+#endif
+
+/*****************************************************************************/
+
+#if ECB_CPP
+ #define ecb_inline static inline
+#elif ECB_GCC_VERSION(2,5)
+ #define ecb_inline static __inline__
+#elif ECB_C99
+ #define ecb_inline static inline
+#else
+ #define ecb_inline static
+#endif
+
+#if ECB_GCC_VERSION(3,3)
+ #define ecb_restrict __restrict__
+#elif ECB_C99
+ #define ecb_restrict restrict
+#else
+ #define ecb_restrict
+#endif
+
+typedef int ecb_bool;
+
+#define ECB_CONCAT_(a, b) a ## b
+#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
+#define ECB_STRINGIFY_(a) # a
+#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)
+#define ECB_STRINGIFY_EXPR(expr) ((expr), ECB_STRINGIFY_ (expr))
+
+#define ecb_function_ ecb_inline
+
+#if ECB_GCC_VERSION(3,1) || ECB_CLANG_VERSION(2,8)
+ #define ecb_attribute(attrlist) __attribute__ (attrlist)
+#else
+ #define ecb_attribute(attrlist)
+#endif
+
+#if ECB_GCC_VERSION(3,1) || ECB_CLANG_BUILTIN(__builtin_constant_p)
+ #define ecb_is_constant(expr) __builtin_constant_p (expr)
+#else
+ /* possible C11 impl for integral types
+ typedef struct ecb_is_constant_struct ecb_is_constant_struct;
+ #define ecb_is_constant(expr) _Generic ((1 ? (struct ecb_is_constant_struct *)0 : (void *)((expr) - (expr)), ecb_is_constant_struct *: 0, default: 1)) */
+
+ #define ecb_is_constant(expr) 0
+#endif
+
+#if ECB_GCC_VERSION(3,1) || ECB_CLANG_BUILTIN(__builtin_expect)
+ #define ecb_expect(expr,value) __builtin_expect ((expr),(value))
+#else
+ #define ecb_expect(expr,value) (expr)
+#endif
+
+#if ECB_GCC_VERSION(3,1) || ECB_CLANG_BUILTIN(__builtin_prefetch)
+ #define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
+#else
+ #define ecb_prefetch(addr,rw,locality)
+#endif
+
+/* no emulation for ecb_decltype */
+#if ECB_CPP11
+ // older implementations might have problems with decltype(x)::type, work around it
+ template<class T> struct ecb_decltype_t { typedef T type; };
+ #define ecb_decltype(x) ecb_decltype_t<decltype (x)>::type
+#elif ECB_GCC_VERSION(3,0) || ECB_CLANG_VERSION(2,8)
+ #define ecb_decltype(x) __typeof__ (x)
+#endif
+
+#if _MSC_VER >= 1300
+ #define ecb_deprecated __declspec (deprecated)
+#else
+ #define ecb_deprecated ecb_attribute ((__deprecated__))
+#endif
+
+#if _MSC_VER >= 1500
+ #define ecb_deprecated_message(msg) __declspec (deprecated (msg))
+#elif ECB_GCC_VERSION(4,5)
+ #define ecb_deprecated_message(msg) ecb_attribute ((__deprecated__ (msg))
+#else
+ #define ecb_deprecated_message(msg) ecb_deprecated
+#endif
+
+#if _MSC_VER >= 1400
+ #define ecb_noinline __declspec (noinline)
+#else
+ #define ecb_noinline ecb_attribute ((__noinline__))
+#endif
+
+#define ecb_unused ecb_attribute ((__unused__))
+#define ecb_const ecb_attribute ((__const__))
+#define ecb_pure ecb_attribute ((__pure__))
+
+#if ECB_C11 || __IBMC_NORETURN
+ /* http://www-01.ibm.com/support/knowledgecenter/SSGH3R_13.1.0/com.ibm.xlcpp131.aix.doc/language_ref/noreturn.html */
+ #define ecb_noreturn _Noreturn
+#elif ECB_CPP11
+ #define ecb_noreturn [[noreturn]]
+#elif _MSC_VER >= 1200
+ /* http://msdn.microsoft.com/en-us/library/k6ktzx3s.aspx */
+ #define ecb_noreturn __declspec (noreturn)
+#else
+ #define ecb_noreturn ecb_attribute ((__noreturn__))
+#endif
+
+#if ECB_GCC_VERSION(4,3)
+ #define ecb_artificial ecb_attribute ((__artificial__))
+ #define ecb_hot ecb_attribute ((__hot__))
+ #define ecb_cold ecb_attribute ((__cold__))
+#else
+ #define ecb_artificial
+ #define ecb_hot
+ #define ecb_cold
+#endif
+
+/* put around conditional expressions if you are very sure that the */
+/* expression is mostly true or mostly false. note that these return */
+/* booleans, not the expression. */
+#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
+#define ecb_expect_true(expr) ecb_expect (!!(expr), 1)
+/* for compatibility to the rest of the world */
+#define ecb_likely(expr) ecb_expect_true (expr)
+#define ecb_unlikely(expr) ecb_expect_false (expr)
+
+/* count trailing zero bits and count # of one bits */
+#if ECB_GCC_VERSION(3,4) \
+ || (ECB_CLANG_BUILTIN(__builtin_clz) && ECB_CLANG_BUILTIN(__builtin_clzll) \
+ && ECB_CLANG_BUILTIN(__builtin_ctz) && ECB_CLANG_BUILTIN(__builtin_ctzll) \
+ && ECB_CLANG_BUILTIN(__builtin_popcount))
+ /* we assume int == 32 bit, long == 32 or 64 bit and long long == 64 bit */
+ #define ecb_ld32(x) (__builtin_clz (x) ^ 31)
+ #define ecb_ld64(x) (__builtin_clzll (x) ^ 63)
+ #define ecb_ctz32(x) __builtin_ctz (x)
+ #define ecb_ctz64(x) __builtin_ctzll (x)
+ #define ecb_popcount32(x) __builtin_popcount (x)
+ /* no popcountll */
+#else
+ ecb_function_ ecb_const int ecb_ctz32 (uint32_t x);
+ ecb_function_ ecb_const int
+ ecb_ctz32 (uint32_t x)
+ {
+#if 1400 <= _MSC_VER && (_M_IX86 || _M_X64 || _M_IA64 || _M_ARM)
+ unsigned long r;
+ _BitScanForward (&r, x);
+ return (int)r;
+#else
+ int r = 0;
+
+ x &= ~x + 1; /* this isolates the lowest bit */
+
+#if ECB_branchless_on_i386
+ r += !!(x & 0xaaaaaaaa) << 0;
+ r += !!(x & 0xcccccccc) << 1;
+ r += !!(x & 0xf0f0f0f0) << 2;
+ r += !!(x & 0xff00ff00) << 3;
+ r += !!(x & 0xffff0000) << 4;
+#else
+ if (x & 0xaaaaaaaa) r += 1;
+ if (x & 0xcccccccc) r += 2;
+ if (x & 0xf0f0f0f0) r += 4;
+ if (x & 0xff00ff00) r += 8;
+ if (x & 0xffff0000) r += 16;
+#endif
+
+ return r;
+#endif
+ }
+
+ ecb_function_ ecb_const int ecb_ctz64 (uint64_t x);
+ ecb_function_ ecb_const int
+ ecb_ctz64 (uint64_t x)
+ {
+#if 1400 <= _MSC_VER && (_M_X64 || _M_IA64 || _M_ARM)
+ unsigned long r;
+ _BitScanForward64 (&r, x);
+ return (int)r;
+#else
+ int shift = x & 0xffffffff ? 0 : 32;
+ return ecb_ctz32 (x >> shift) + shift;
+#endif
+ }
+
+ ecb_function_ ecb_const int ecb_popcount32 (uint32_t x);
+ ecb_function_ ecb_const int
+ ecb_popcount32 (uint32_t x)
+ {
+ x -= (x >> 1) & 0x55555555;
+ x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
+ x = ((x >> 4) + x) & 0x0f0f0f0f;
+ x *= 0x01010101;
+
+ return x >> 24;
+ }
+
+ ecb_function_ ecb_const int ecb_ld32 (uint32_t x);
+ ecb_function_ ecb_const int ecb_ld32 (uint32_t x)
+ {
+#if 1400 <= _MSC_VER && (_M_IX86 || _M_X64 || _M_IA64 || _M_ARM)
+ unsigned long r;
+ _BitScanReverse (&r, x);
+ return (int)r;
+#else
+ int r = 0;
+
+ if (x >> 16) { x >>= 16; r += 16; }
+ if (x >> 8) { x >>= 8; r += 8; }
+ if (x >> 4) { x >>= 4; r += 4; }
+ if (x >> 2) { x >>= 2; r += 2; }
+ if (x >> 1) { r += 1; }
+
+ return r;
+#endif
+ }
+
+ ecb_function_ ecb_const int ecb_ld64 (uint64_t x);
+ ecb_function_ ecb_const int ecb_ld64 (uint64_t x)
+ {
+#if 1400 <= _MSC_VER && (_M_X64 || _M_IA64 || _M_ARM)
+ unsigned long r;
+ _BitScanReverse64 (&r, x);
+ return (int)r;
+#else
+ int r = 0;
+
+ if (x >> 32) { x >>= 32; r += 32; }
+
+ return r + ecb_ld32 (x);
+#endif
+ }
+#endif
+
+ecb_function_ ecb_const ecb_bool ecb_is_pot32 (uint32_t x);
+ecb_function_ ecb_const ecb_bool ecb_is_pot32 (uint32_t x) { return !(x & (x - 1)); }
+ecb_function_ ecb_const ecb_bool ecb_is_pot64 (uint64_t x);
+ecb_function_ ecb_const ecb_bool ecb_is_pot64 (uint64_t x) { return !(x & (x - 1)); }
+
+ecb_function_ ecb_const uint8_t ecb_bitrev8 (uint8_t x);
+ecb_function_ ecb_const uint8_t ecb_bitrev8 (uint8_t x)
+{
+ return ( (x * 0x0802U & 0x22110U)
+ | (x * 0x8020U & 0x88440U)) * 0x10101U >> 16;
+}
+
+ecb_function_ ecb_const uint16_t ecb_bitrev16 (uint16_t x);
+ecb_function_ ecb_const uint16_t ecb_bitrev16 (uint16_t x)
+{
+ x = ((x >> 1) & 0x5555) | ((x & 0x5555) << 1);
+ x = ((x >> 2) & 0x3333) | ((x & 0x3333) << 2);
+ x = ((x >> 4) & 0x0f0f) | ((x & 0x0f0f) << 4);
+ x = ( x >> 8 ) | ( x << 8);
+
+ return x;
+}
+
+ecb_function_ ecb_const uint32_t ecb_bitrev32 (uint32_t x);
+ecb_function_ ecb_const uint32_t ecb_bitrev32 (uint32_t x)
+{
+ x = ((x >> 1) & 0x55555555) | ((x & 0x55555555) << 1);
+ x = ((x >> 2) & 0x33333333) | ((x & 0x33333333) << 2);
+ x = ((x >> 4) & 0x0f0f0f0f) | ((x & 0x0f0f0f0f) << 4);
+ x = ((x >> 8) & 0x00ff00ff) | ((x & 0x00ff00ff) << 8);
+ x = ( x >> 16 ) | ( x << 16);
+
+ return x;
+}
+
+/* popcount64 is only available on 64 bit cpus as gcc builtin */
+/* so for this version we are lazy */
+ecb_function_ ecb_const int ecb_popcount64 (uint64_t x);
+ecb_function_ ecb_const int
+ecb_popcount64 (uint64_t x)
+{
+ return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
+}
+
+ecb_inline ecb_const uint8_t ecb_rotl8 (uint8_t x, unsigned int count);
+ecb_inline ecb_const uint8_t ecb_rotr8 (uint8_t x, unsigned int count);
+ecb_inline ecb_const uint16_t ecb_rotl16 (uint16_t x, unsigned int count);
+ecb_inline ecb_const uint16_t ecb_rotr16 (uint16_t x, unsigned int count);
+ecb_inline ecb_const uint32_t ecb_rotl32 (uint32_t x, unsigned int count);
+ecb_inline ecb_const uint32_t ecb_rotr32 (uint32_t x, unsigned int count);
+ecb_inline ecb_const uint64_t ecb_rotl64 (uint64_t x, unsigned int count);
+ecb_inline ecb_const uint64_t ecb_rotr64 (uint64_t x, unsigned int count);
+
+ecb_inline ecb_const uint8_t ecb_rotl8 (uint8_t x, unsigned int count) { return (x >> ( 8 - count)) | (x << count); }
+ecb_inline ecb_const uint8_t ecb_rotr8 (uint8_t x, unsigned int count) { return (x << ( 8 - count)) | (x >> count); }
+ecb_inline ecb_const uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (16 - count)) | (x << count); }
+ecb_inline ecb_const uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (16 - count)) | (x >> count); }
+ecb_inline ecb_const uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (32 - count)) | (x << count); }
+ecb_inline ecb_const uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (32 - count)) | (x >> count); }
+ecb_inline ecb_const uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (64 - count)) | (x << count); }
+ecb_inline ecb_const uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (64 - count)) | (x >> count); }
+
+#if ECB_CPP
+
+inline uint8_t ecb_ctz (uint8_t v) { return ecb_ctz32 (v); }
+inline uint16_t ecb_ctz (uint16_t v) { return ecb_ctz32 (v); }
+inline uint32_t ecb_ctz (uint32_t v) { return ecb_ctz32 (v); }
+inline uint64_t ecb_ctz (uint64_t v) { return ecb_ctz64 (v); }
+
+inline bool ecb_is_pot (uint8_t v) { return ecb_is_pot32 (v); }
+inline bool ecb_is_pot (uint16_t v) { return ecb_is_pot32 (v); }
+inline bool ecb_is_pot (uint32_t v) { return ecb_is_pot32 (v); }
+inline bool ecb_is_pot (uint64_t v) { return ecb_is_pot64 (v); }
+
+inline int ecb_ld (uint8_t v) { return ecb_ld32 (v); }
+inline int ecb_ld (uint16_t v) { return ecb_ld32 (v); }
+inline int ecb_ld (uint32_t v) { return ecb_ld32 (v); }
+inline int ecb_ld (uint64_t v) { return ecb_ld64 (v); }
+
+inline int ecb_popcount (uint8_t v) { return ecb_popcount32 (v); }
+inline int ecb_popcount (uint16_t v) { return ecb_popcount32 (v); }
+inline int ecb_popcount (uint32_t v) { return ecb_popcount32 (v); }
+inline int ecb_popcount (uint64_t v) { return ecb_popcount64 (v); }
+
+inline uint8_t ecb_bitrev (uint8_t v) { return ecb_bitrev8 (v); }
+inline uint16_t ecb_bitrev (uint16_t v) { return ecb_bitrev16 (v); }
+inline uint32_t ecb_bitrev (uint32_t v) { return ecb_bitrev32 (v); }
+
+inline uint8_t ecb_rotl (uint8_t v, unsigned int count) { return ecb_rotl8 (v, count); }
+inline uint16_t ecb_rotl (uint16_t v, unsigned int count) { return ecb_rotl16 (v, count); }
+inline uint32_t ecb_rotl (uint32_t v, unsigned int count) { return ecb_rotl32 (v, count); }
+inline uint64_t ecb_rotl (uint64_t v, unsigned int count) { return ecb_rotl64 (v, count); }
+
+inline uint8_t ecb_rotr (uint8_t v, unsigned int count) { return ecb_rotr8 (v, count); }
+inline uint16_t ecb_rotr (uint16_t v, unsigned int count) { return ecb_rotr16 (v, count); }
+inline uint32_t ecb_rotr (uint32_t v, unsigned int count) { return ecb_rotr32 (v, count); }
+inline uint64_t ecb_rotr (uint64_t v, unsigned int count) { return ecb_rotr64 (v, count); }
+
+#endif
+
+#if ECB_GCC_VERSION(4,3) || (ECB_CLANG_BUILTIN(__builtin_bswap32) && ECB_CLANG_BUILTIN(__builtin_bswap64))
+ #if ECB_GCC_VERSION(4,8) || ECB_CLANG_BUILTIN(__builtin_bswap16)
+ #define ecb_bswap16(x) __builtin_bswap16 (x)
+ #else
+ #define ecb_bswap16(x) (__builtin_bswap32 (x) >> 16)
+ #endif
+ #define ecb_bswap32(x) __builtin_bswap32 (x)
+ #define ecb_bswap64(x) __builtin_bswap64 (x)
+#elif _MSC_VER
+ #include <stdlib.h>
+ #define ecb_bswap16(x) ((uint16_t)_byteswap_ushort ((uint16_t)(x)))
+ #define ecb_bswap32(x) ((uint32_t)_byteswap_ulong ((uint32_t)(x)))
+ #define ecb_bswap64(x) ((uint64_t)_byteswap_uint64 ((uint64_t)(x)))
+#else
+ ecb_function_ ecb_const uint16_t ecb_bswap16 (uint16_t x);
+ ecb_function_ ecb_const uint16_t
+ ecb_bswap16 (uint16_t x)
+ {
+ return ecb_rotl16 (x, 8);
+ }
+
+ ecb_function_ ecb_const uint32_t ecb_bswap32 (uint32_t x);
+ ecb_function_ ecb_const uint32_t
+ ecb_bswap32 (uint32_t x)
+ {
+ return (((uint32_t)ecb_bswap16 (x)) << 16) | ecb_bswap16 (x >> 16);
+ }
+
+ ecb_function_ ecb_const uint64_t ecb_bswap64 (uint64_t x);
+ ecb_function_ ecb_const uint64_t
+ ecb_bswap64 (uint64_t x)
+ {
+ return (((uint64_t)ecb_bswap32 (x)) << 32) | ecb_bswap32 (x >> 32);
+ }
+#endif
+
+#if ECB_GCC_VERSION(4,5) || ECB_CLANG_BUILTIN(__builtin_unreachable)
+ #define ecb_unreachable() __builtin_unreachable ()
+#else
+ /* this seems to work fine, but gcc always emits a warning for it :/ */
+ ecb_inline ecb_noreturn void ecb_unreachable (void);
+ ecb_inline ecb_noreturn void ecb_unreachable (void) { }
+#endif
+
+/* try to tell the compiler that some condition is definitely true */
+#define ecb_assume(cond) if (!(cond)) ecb_unreachable (); else 0
+
+ecb_inline ecb_const uint32_t ecb_byteorder_helper (void);
+ecb_inline ecb_const uint32_t
+ecb_byteorder_helper (void)
+{
+ /* the union code still generates code under pressure in gcc, */
+ /* but less than using pointers, and always seems to */
+ /* successfully return a constant. */
+ /* the reason why we have this horrible preprocessor mess */
+ /* is to avoid it in all cases, at least on common architectures */
+ /* or when using a recent enough gcc version (>= 4.6) */
+#if (defined __BYTE_ORDER__ && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) \
+ || ((__i386 || __i386__ || _M_IX86 || ECB_GCC_AMD64 || ECB_MSVC_AMD64) && !__VOS__)
+ #define ECB_LITTLE_ENDIAN 1
+ return 0x44332211;
+#elif (defined __BYTE_ORDER__ && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) \
+ || ((__AARCH64EB__ || __MIPSEB__ || __ARMEB__) && !__VOS__)
+ #define ECB_BIG_ENDIAN 1
+ return 0x11223344;
+#else
+ union
+ {
+ uint8_t c[4];
+ uint32_t u;
+ } u = { 0x11, 0x22, 0x33, 0x44 };
+ return u.u;
+#endif
+}
+
+ecb_inline ecb_const ecb_bool ecb_big_endian (void);
+ecb_inline ecb_const ecb_bool ecb_big_endian (void) { return ecb_byteorder_helper () == 0x11223344; }
+ecb_inline ecb_const ecb_bool ecb_little_endian (void);
+ecb_inline ecb_const ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44332211; }
+
+/*****************************************************************************/
+/* unaligned load/store */
+
+ecb_inline uint_fast16_t ecb_be_u16_to_host (uint_fast16_t v) { return ecb_little_endian () ? ecb_bswap16 (v) : v; }
+ecb_inline uint_fast32_t ecb_be_u32_to_host (uint_fast32_t v) { return ecb_little_endian () ? ecb_bswap32 (v) : v; }
+ecb_inline uint_fast64_t ecb_be_u64_to_host (uint_fast64_t v) { return ecb_little_endian () ? ecb_bswap64 (v) : v; }
+
+ecb_inline uint_fast16_t ecb_le_u16_to_host (uint_fast16_t v) { return ecb_big_endian () ? ecb_bswap16 (v) : v; }
+ecb_inline uint_fast32_t ecb_le_u32_to_host (uint_fast32_t v) { return ecb_big_endian () ? ecb_bswap32 (v) : v; }
+ecb_inline uint_fast64_t ecb_le_u64_to_host (uint_fast64_t v) { return ecb_big_endian () ? ecb_bswap64 (v) : v; }
+
+ecb_inline uint_fast16_t ecb_peek_u16_u (const void *ptr) { uint16_t v; memcpy (&v, ptr, sizeof (v)); return v; }
+ecb_inline uint_fast32_t ecb_peek_u32_u (const void *ptr) { uint32_t v; memcpy (&v, ptr, sizeof (v)); return v; }
+ecb_inline uint_fast64_t ecb_peek_u64_u (const void *ptr) { uint64_t v; memcpy (&v, ptr, sizeof (v)); return v; }
+
+ecb_inline uint_fast16_t ecb_peek_be_u16_u (const void *ptr) { return ecb_be_u16_to_host (ecb_peek_u16_u (ptr)); }
+ecb_inline uint_fast32_t ecb_peek_be_u32_u (const void *ptr) { return ecb_be_u32_to_host (ecb_peek_u32_u (ptr)); }
+ecb_inline uint_fast64_t ecb_peek_be_u64_u (const void *ptr) { return ecb_be_u64_to_host (ecb_peek_u64_u (ptr)); }
+
+ecb_inline uint_fast16_t ecb_peek_le_u16_u (const void *ptr) { return ecb_le_u16_to_host (ecb_peek_u16_u (ptr)); }
+ecb_inline uint_fast32_t ecb_peek_le_u32_u (const void *ptr) { return ecb_le_u32_to_host (ecb_peek_u32_u (ptr)); }
+ecb_inline uint_fast64_t ecb_peek_le_u64_u (const void *ptr) { return ecb_le_u64_to_host (ecb_peek_u64_u (ptr)); }
+
+ecb_inline uint_fast16_t ecb_host_to_be_u16 (uint_fast16_t v) { return ecb_little_endian () ? ecb_bswap16 (v) : v; }
+ecb_inline uint_fast32_t ecb_host_to_be_u32 (uint_fast32_t v) { return ecb_little_endian () ? ecb_bswap32 (v) : v; }
+ecb_inline uint_fast64_t ecb_host_to_be_u64 (uint_fast64_t v) { return ecb_little_endian () ? ecb_bswap64 (v) : v; }
+
+ecb_inline uint_fast16_t ecb_host_to_le_u16 (uint_fast16_t v) { return ecb_big_endian () ? ecb_bswap16 (v) : v; }
+ecb_inline uint_fast32_t ecb_host_to_le_u32 (uint_fast32_t v) { return ecb_big_endian () ? ecb_bswap32 (v) : v; }
+ecb_inline uint_fast64_t ecb_host_to_le_u64 (uint_fast64_t v) { return ecb_big_endian () ? ecb_bswap64 (v) : v; }
+
+ecb_inline void ecb_poke_u16_u (void *ptr, uint16_t v) { memcpy (ptr, &v, sizeof (v)); }
+ecb_inline void ecb_poke_u32_u (void *ptr, uint32_t v) { memcpy (ptr, &v, sizeof (v)); }
+ecb_inline void ecb_poke_u64_u (void *ptr, uint64_t v) { memcpy (ptr, &v, sizeof (v)); }
+
+ecb_inline void ecb_poke_be_u16_u (void *ptr, uint_fast16_t v) { ecb_poke_u16_u (ptr, ecb_host_to_be_u16 (v)); }
+ecb_inline void ecb_poke_be_u32_u (void *ptr, uint_fast32_t v) { ecb_poke_u32_u (ptr, ecb_host_to_be_u32 (v)); }
+ecb_inline void ecb_poke_be_u64_u (void *ptr, uint_fast64_t v) { ecb_poke_u64_u (ptr, ecb_host_to_be_u64 (v)); }
+
+ecb_inline void ecb_poke_le_u16_u (void *ptr, uint_fast16_t v) { ecb_poke_u16_u (ptr, ecb_host_to_le_u16 (v)); }
+ecb_inline void ecb_poke_le_u32_u (void *ptr, uint_fast32_t v) { ecb_poke_u32_u (ptr, ecb_host_to_le_u32 (v)); }
+ecb_inline void ecb_poke_le_u64_u (void *ptr, uint_fast64_t v) { ecb_poke_u64_u (ptr, ecb_host_to_le_u64 (v)); }
+
+#if ECB_CPP
+
+inline uint8_t ecb_bswap (uint8_t v) { return v; }
+inline uint16_t ecb_bswap (uint16_t v) { return ecb_bswap16 (v); }
+inline uint32_t ecb_bswap (uint32_t v) { return ecb_bswap32 (v); }
+inline uint64_t ecb_bswap (uint64_t v) { return ecb_bswap64 (v); }
+
+template<typename T> inline T ecb_be_to_host (T v) { return ecb_little_endian () ? ecb_bswap (v) : v; }
+template<typename T> inline T ecb_le_to_host (T v) { return ecb_big_endian () ? ecb_bswap (v) : v; }
+template<typename T> inline T ecb_peek (const void *ptr) { return *(const T *)ptr; }
+template<typename T> inline T ecb_peek_be (const void *ptr) { return ecb_be_to_host (ecb_peek <T> (ptr)); }
+template<typename T> inline T ecb_peek_le (const void *ptr) { return ecb_le_to_host (ecb_peek <T> (ptr)); }
+template<typename T> inline T ecb_peek_u (const void *ptr) { T v; memcpy (&v, ptr, sizeof (v)); return v; }
+template<typename T> inline T ecb_peek_be_u (const void *ptr) { return ecb_be_to_host (ecb_peek_u<T> (ptr)); }
+template<typename T> inline T ecb_peek_le_u (const void *ptr) { return ecb_le_to_host (ecb_peek_u<T> (ptr)); }
+
+template<typename T> inline T ecb_host_to_be (T v) { return ecb_little_endian () ? ecb_bswap (v) : v; }
+template<typename T> inline T ecb_host_to_le (T v) { return ecb_big_endian () ? ecb_bswap (v) : v; }
+template<typename T> inline void ecb_poke (void *ptr, T v) { *(T *)ptr = v; }
+template<typename T> inline void ecb_poke_be (void *ptr, T v) { return ecb_poke <T> (ptr, ecb_host_to_be (v)); }
+template<typename T> inline void ecb_poke_le (void *ptr, T v) { return ecb_poke <T> (ptr, ecb_host_to_le (v)); }
+template<typename T> inline void ecb_poke_u (void *ptr, T v) { memcpy (ptr, &v, sizeof (v)); }
+template<typename T> inline void ecb_poke_be_u (void *ptr, T v) { return ecb_poke_u<T> (ptr, ecb_host_to_be (v)); }
+template<typename T> inline void ecb_poke_le_u (void *ptr, T v) { return ecb_poke_u<T> (ptr, ecb_host_to_le (v)); }
+
+#endif
+
+/*****************************************************************************/
+
+#if ECB_GCC_VERSION(3,0) || ECB_C99
+ #define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
+#else
+ #define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
+#endif
+
+#if ECB_CPP
+ template<typename T>
+ static inline T ecb_div_rd (T val, T div)
+ {
+ return val < 0 ? - ((-val + div - 1) / div) : (val ) / div;
+ }
+ template<typename T>
+ static inline T ecb_div_ru (T val, T div)
+ {
+ return val < 0 ? - ((-val ) / div) : (val + div - 1) / div;
+ }
+#else
+ #define ecb_div_rd(val,div) ((val) < 0 ? - ((-(val) + (div) - 1) / (div)) : ((val) ) / (div))
+ #define ecb_div_ru(val,div) ((val) < 0 ? - ((-(val) ) / (div)) : ((val) + (div) - 1) / (div))
+#endif
+
+#if ecb_cplusplus_does_not_suck
+ /* does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm) */
+ template<typename T, int N>
+ static inline int ecb_array_length (const T (&arr)[N])
+ {
+ return N;
+ }
+#else
+ #define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
+#endif
+
+/*****************************************************************************/
+
+ecb_function_ ecb_const uint32_t ecb_binary16_to_binary32 (uint32_t x);
+ecb_function_ ecb_const uint32_t
+ecb_binary16_to_binary32 (uint32_t x)
+{
+ unsigned int s = (x & 0x8000) << (31 - 15);
+ int e = (x >> 10) & 0x001f;
+ unsigned int m = x & 0x03ff;
+
+ if (ecb_expect_false (e == 31))
+ /* infinity or NaN */
+ e = 255 - (127 - 15);
+ else if (ecb_expect_false (!e))
+ {
+ if (ecb_expect_true (!m))
+ /* zero, handled by code below by forcing e to 0 */
+ e = 0 - (127 - 15);
+ else
+ {
+ /* subnormal, renormalise */
+ unsigned int s = 10 - ecb_ld32 (m);
+
+ m = (m << s) & 0x3ff; /* mask implicit bit */
+ e -= s - 1;
+ }
+ }
+
+ /* e and m now are normalised, or zero, (or inf or nan) */
+ e += 127 - 15;
+
+ return s | (e << 23) | (m << (23 - 10));
+}
+
+ecb_function_ ecb_const uint16_t ecb_binary32_to_binary16 (uint32_t x);
+ecb_function_ ecb_const uint16_t
+ecb_binary32_to_binary16 (uint32_t x)
+{
+ unsigned int s = (x >> 16) & 0x00008000; /* sign bit, the easy part */
+ unsigned int e = ((x >> 23) & 0x000000ff) - (127 - 15); /* the desired exponent */
+ unsigned int m = x & 0x007fffff;
+
+ x &= 0x7fffffff;
+
+ /* if it's within range of binary16 normals, use fast path */
+ if (ecb_expect_true (0x38800000 <= x && x <= 0x477fefff))
+ {
+ /* mantissa round-to-even */
+ m += 0x00000fff + ((m >> (23 - 10)) & 1);
+
+ /* handle overflow */
+ if (ecb_expect_false (m >= 0x00800000))
+ {
+ m >>= 1;
+ e += 1;
+ }
+
+ return s | (e << 10) | (m >> (23 - 10));
+ }
+
+ /* handle large numbers and infinity */
+ if (ecb_expect_true (0x477fefff < x && x <= 0x7f800000))
+ return s | 0x7c00;
+
+ /* handle zero, subnormals and small numbers */
+ if (ecb_expect_true (x < 0x38800000))
+ {
+ /* zero */
+ if (ecb_expect_true (!x))
+ return s;
+
+ /* handle subnormals */
+
+ /* too small, will be zero */
+ if (e < (14 - 24)) /* might not be sharp, but is good enough */
+ return s;
+
+ m |= 0x00800000; /* make implicit bit explicit */
+
+ /* very tricky - we need to round to the nearest e (+10) bit value */
+ {
+ unsigned int bits = 14 - e;
+ unsigned int half = (1 << (bits - 1)) - 1;
+ unsigned int even = (m >> bits) & 1;
+
+ /* if this overflows, we will end up with a normalised number */
+ m = (m + half + even) >> bits;
+ }
+
+ return s | m;
+ }
+
+ /* handle NaNs, preserve leftmost nan bits, but make sure we don't turn them into infinities */
+ m >>= 13;
+
+ return s | 0x7c00 | m | !m;
+}
+
+/*******************************************************************************/
+/* floating point stuff, can be disabled by defining ECB_NO_LIBM */
+
+/* basically, everything uses "ieee pure-endian" floating point numbers */
+/* the only noteworthy exception is ancient armle, which uses order 43218765 */
+#if 0 \
+ || __i386 || __i386__ \
+ || ECB_GCC_AMD64 \
+ || __powerpc__ || __ppc__ || __powerpc64__ || __ppc64__ \
+ || defined __s390__ || defined __s390x__ \
+ || defined __mips__ \
+ || defined __alpha__ \
+ || defined __hppa__ \
+ || defined __ia64__ \
+ || defined __m68k__ \
+ || defined __m88k__ \
+ || defined __sh__ \
+ || defined _M_IX86 || defined ECB_MSVC_AMD64 || defined _M_IA64 \
+ || (defined __arm__ && (defined __ARM_EABI__ || defined __EABI__ || defined __VFP_FP__ || defined _WIN32_WCE || defined __ANDROID__)) \
+ || defined __aarch64__
+ #define ECB_STDFP 1
+#else
+ #define ECB_STDFP 0
+#endif
+
+#ifndef ECB_NO_LIBM
+
+ #include <math.h> /* for frexp*, ldexp*, INFINITY, NAN */
+
+ /* only the oldest of old doesn't have this one. solaris. */
+ #ifdef INFINITY
+ #define ECB_INFINITY INFINITY
+ #else
+ #define ECB_INFINITY HUGE_VAL
+ #endif
+
+ #ifdef NAN
+ #define ECB_NAN NAN
+ #else
+ #define ECB_NAN ECB_INFINITY
+ #endif
+
+ #if ECB_C99 || _XOPEN_VERSION >= 600 || _POSIX_VERSION >= 200112L
+ #define ecb_ldexpf(x,e) ldexpf ((x), (e))
+ #define ecb_frexpf(x,e) frexpf ((x), (e))
+ #else
+ #define ecb_ldexpf(x,e) (float) ldexp ((double) (x), (e))
+ #define ecb_frexpf(x,e) (float) frexp ((double) (x), (e))
+ #endif
+
+ /* convert a float to ieee single/binary32 */
+ ecb_function_ ecb_const uint32_t ecb_float_to_binary32 (float x);
+ ecb_function_ ecb_const uint32_t
+ ecb_float_to_binary32 (float x)
+ {
+ uint32_t r;
+
+ #if ECB_STDFP
+ memcpy (&r, &x, 4);
+ #else
+ /* slow emulation, works for anything but -0 */
+ uint32_t m;
+ int e;
+
+ if (x == 0e0f ) return 0x00000000U;
+ if (x > +3.40282346638528860e+38f) return 0x7f800000U;
+ if (x < -3.40282346638528860e+38f) return 0xff800000U;
+ if (x != x ) return 0x7fbfffffU;
+
+ m = ecb_frexpf (x, &e) * 0x1000000U;
+
+ r = m & 0x80000000U;
+
+ if (r)
+ m = -m;
+
+ if (e <= -126)
+ {
+ m &= 0xffffffU;
+ m >>= (-125 - e);
+ e = -126;
+ }
+
+ r |= (e + 126) << 23;
+ r |= m & 0x7fffffU;
+ #endif
+
+ return r;
+ }
+
+ /* converts an ieee single/binary32 to a float */
+ ecb_function_ ecb_const float ecb_binary32_to_float (uint32_t x);
+ ecb_function_ ecb_const float
+ ecb_binary32_to_float (uint32_t x)
+ {
+ float r;
+
+ #if ECB_STDFP
+ memcpy (&r, &x, 4);
+ #else
+ /* emulation, only works for normals and subnormals and +0 */
+ int neg = x >> 31;
+ int e = (x >> 23) & 0xffU;
+
+ x &= 0x7fffffU;
+
+ if (e)
+ x |= 0x800000U;
+ else
+ e = 1;
+
+ /* we distrust ldexpf a bit and do the 2**-24 scaling by an extra multiply */
+ r = ecb_ldexpf (x * (0.5f / 0x800000U), e - 126);
+
+ r = neg ? -r : r;
+ #endif
+
+ return r;
+ }
+
+ /* convert a double to ieee double/binary64 */
+ ecb_function_ ecb_const uint64_t ecb_double_to_binary64 (double x);
+ ecb_function_ ecb_const uint64_t
+ ecb_double_to_binary64 (double x)
+ {
+ uint64_t r;
+
+ #if ECB_STDFP
+ memcpy (&r, &x, 8);
+ #else
+ /* slow emulation, works for anything but -0 */
+ uint64_t m;
+ int e;
+
+ if (x == 0e0 ) return 0x0000000000000000U;
+ if (x > +1.79769313486231470e+308) return 0x7ff0000000000000U;
+ if (x < -1.79769313486231470e+308) return 0xfff0000000000000U;
+ if (x != x ) return 0X7ff7ffffffffffffU;
+
+ m = frexp (x, &e) * 0x20000000000000U;
+
+ r = m & 0x8000000000000000;;
+
+ if (r)
+ m = -m;
+
+ if (e <= -1022)
+ {
+ m &= 0x1fffffffffffffU;
+ m >>= (-1021 - e);
+ e = -1022;
+ }
+
+ r |= ((uint64_t)(e + 1022)) << 52;
+ r |= m & 0xfffffffffffffU;
+ #endif
+
+ return r;
+ }
+
+ /* converts an ieee double/binary64 to a double */
+ ecb_function_ ecb_const double ecb_binary64_to_double (uint64_t x);
+ ecb_function_ ecb_const double
+ ecb_binary64_to_double (uint64_t x)
+ {
+ double r;
+
+ #if ECB_STDFP
+ memcpy (&r, &x, 8);
+ #else
+ /* emulation, only works for normals and subnormals and +0 */
+ int neg = x >> 63;
+ int e = (x >> 52) & 0x7ffU;
+
+ x &= 0xfffffffffffffU;
+
+ if (e)
+ x |= 0x10000000000000U;
+ else
+ e = 1;
+
+ /* we distrust ldexp a bit and do the 2**-53 scaling by an extra multiply */
+ r = ldexp (x * (0.5 / 0x10000000000000U), e - 1022);
+
+ r = neg ? -r : r;
+ #endif
+
+ return r;
+ }
+
+ /* convert a float to ieee half/binary16 */
+ ecb_function_ ecb_const uint16_t ecb_float_to_binary16 (float x);
+ ecb_function_ ecb_const uint16_t
+ ecb_float_to_binary16 (float x)
+ {
+ return ecb_binary32_to_binary16 (ecb_float_to_binary32 (x));
+ }
+
+ /* convert an ieee half/binary16 to float */
+ ecb_function_ ecb_const float ecb_binary16_to_float (uint16_t x);
+ ecb_function_ ecb_const float
+ ecb_binary16_to_float (uint16_t x)
+ {
+ return ecb_binary32_to_float (ecb_binary16_to_binary32 (x));
+ }
+
+#endif
+
+#endif
+
+/* ECB.H END */
+
+#if ECB_MEMORY_FENCE_NEEDS_PTHREADS
+/* if your architecture doesn't need memory fences, e.g. because it is
+ * single-cpu/core, or if you use libev in a project that doesn't use libev
+ * from multiple threads, then you can define ECB_NO_THREADS when compiling
+ * libev, in which cases the memory fences become nops.
+ * alternatively, you can remove this #error and link against libpthread,
+ * which will then provide the memory fences.
+ */
+# error "memory fences not defined for your architecture, please report"
+#endif
+
+#ifndef ECB_MEMORY_FENCE
+# define ECB_MEMORY_FENCE do { } while (0)
+# define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
+# define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
+#endif
+
+#define inline_size ecb_inline
+
+#if EV_FEATURE_CODE
+# define inline_speed ecb_inline
+#else
+# define inline_speed ecb_noinline static
+#endif
+
+/*****************************************************************************/
+/* raw syscall wrappers */
+
+#if EV_NEED_SYSCALL
+
+#include <sys/syscall.h>
+
+/*
+ * define some syscall wrappers for common architectures
+ * this is mostly for nice looks during debugging, not performance.
+ * our syscalls return < 0, not == -1, on error. which is good
+ * enough for linux aio.
+ * TODO: arm is also common nowadays, maybe even mips and x86
+ * TODO: after implementing this, it suddenly looks like overkill, but its hard to remove...
+ */
+#if __GNUC__ && __linux && ECB_AMD64 && !EV_FEATURE_CODE
+ /* the costly errno access probably kills this for size optimisation */
+
+ #define ev_syscall(nr,narg,arg1,arg2,arg3,arg4,arg5,arg6) \
+ ({ \
+ long res; \
+ register unsigned long r6 __asm__ ("r9" ); \
+ register unsigned long r5 __asm__ ("r8" ); \
+ register unsigned long r4 __asm__ ("r10"); \
+ register unsigned long r3 __asm__ ("rdx"); \
+ register unsigned long r2 __asm__ ("rsi"); \
+ register unsigned long r1 __asm__ ("rdi"); \
+ if (narg >= 6) r6 = (unsigned long)(arg6); \
+ if (narg >= 5) r5 = (unsigned long)(arg5); \
+ if (narg >= 4) r4 = (unsigned long)(arg4); \
+ if (narg >= 3) r3 = (unsigned long)(arg3); \
+ if (narg >= 2) r2 = (unsigned long)(arg2); \
+ if (narg >= 1) r1 = (unsigned long)(arg1); \
+ __asm__ __volatile__ ( \
+ "syscall\n\t" \
+ : "=a" (res) \
+ : "0" (nr), "r" (r1), "r" (r2), "r" (r3), "r" (r4), "r" (r5) \
+ : "cc", "r11", "cx", "memory"); \
+ errno = -res; \
+ res; \
+ })
+
+#endif
+
+#ifdef ev_syscall
+ #define ev_syscall0(nr) ev_syscall (nr, 0, 0, 0, 0, 0, 0, 0)
+ #define ev_syscall1(nr,arg1) ev_syscall (nr, 1, arg1, 0, 0, 0, 0, 0)
+ #define ev_syscall2(nr,arg1,arg2) ev_syscall (nr, 2, arg1, arg2, 0, 0, 0, 0)
+ #define ev_syscall3(nr,arg1,arg2,arg3) ev_syscall (nr, 3, arg1, arg2, arg3, 0, 0, 0)
+ #define ev_syscall4(nr,arg1,arg2,arg3,arg4) ev_syscall (nr, 3, arg1, arg2, arg3, arg4, 0, 0)
+ #define ev_syscall5(nr,arg1,arg2,arg3,arg4,arg5) ev_syscall (nr, 5, arg1, arg2, arg3, arg4, arg5, 0)
+ #define ev_syscall6(nr,arg1,arg2,arg3,arg4,arg5,arg6) ev_syscall (nr, 6, arg1, arg2, arg3, arg4, arg5,arg6)
+#else
+ #define ev_syscall0(nr) syscall (nr)
+ #define ev_syscall1(nr,arg1) syscall (nr, arg1)
+ #define ev_syscall2(nr,arg1,arg2) syscall (nr, arg1, arg2)
+ #define ev_syscall3(nr,arg1,arg2,arg3) syscall (nr, arg1, arg2, arg3)
+ #define ev_syscall4(nr,arg1,arg2,arg3,arg4) syscall (nr, arg1, arg2, arg3, arg4)
+ #define ev_syscall5(nr,arg1,arg2,arg3,arg4,arg5) syscall (nr, arg1, arg2, arg3, arg4, arg5)
+ #define ev_syscall6(nr,arg1,arg2,arg3,arg4,arg5,arg6) syscall (nr, arg1, arg2, arg3, arg4, arg5,arg6)
+#endif
+
+#endif
+
+/*****************************************************************************/
+
+#define NUMPRI (EV_MAXPRI - EV_MINPRI + 1)
+
+#if EV_MINPRI == EV_MAXPRI
+# define ABSPRI(w) (((W)w), 0)
+#else
+# define ABSPRI(w) (((W)w)->priority - EV_MINPRI)
+#endif
+
+#define EMPTY /* required for microsofts broken pseudo-c compiler */
+
+typedef ev_watcher *W;
+typedef ev_watcher_list *WL;
+typedef ev_watcher_time *WT;
+
+#define ev_active(w) ((W)(w))->active
+#define ev_at(w) ((WT)(w))->at
+
+#if EV_USE_REALTIME
+/* sig_atomic_t is used to avoid per-thread variables or locking but still */
+/* giving it a reasonably high chance of working on typical architectures */
+static EV_ATOMIC_T have_realtime; /* did clock_gettime (CLOCK_REALTIME) work? */
+#endif
+
+#if EV_USE_MONOTONIC
+static EV_ATOMIC_T have_monotonic; /* did clock_gettime (CLOCK_MONOTONIC) work? */
+#endif
+
+#ifndef EV_FD_TO_WIN32_HANDLE
+# define EV_FD_TO_WIN32_HANDLE(fd) _get_osfhandle (fd)
+#endif
+#ifndef EV_WIN32_HANDLE_TO_FD
+# define EV_WIN32_HANDLE_TO_FD(handle) _open_osfhandle (handle, 0)
+#endif
+#ifndef EV_WIN32_CLOSE_FD
+# define EV_WIN32_CLOSE_FD(fd) close (fd)
+#endif
+
+#ifdef _WIN32
+# include "ev_win32.c"
+#endif
+
+/*****************************************************************************/
+
+#if EV_USE_LINUXAIO
+# include <linux/aio_abi.h> /* probably only needed for aio_context_t */
+#endif
+
+/* define a suitable floor function (only used by periodics atm) */
+
+#if EV_USE_FLOOR
+# include <math.h>
+# define ev_floor(v) floor (v)
+#else
+
+#include <float.h>
+
+/* a floor() replacement function, should be independent of ev_tstamp type */
+ecb_noinline
+static ev_tstamp
+ev_floor (ev_tstamp v)
+{
+ /* the choice of shift factor is not terribly important */
+#if FLT_RADIX != 2 /* assume FLT_RADIX == 10 */
+ const ev_tstamp shift = sizeof (unsigned long) >= 8 ? 10000000000000000000. : 1000000000.;
+#else
+ const ev_tstamp shift = sizeof (unsigned long) >= 8 ? 18446744073709551616. : 4294967296.;
+#endif
+
+ /* special treatment for negative arguments */
+ if (ecb_expect_false (v < 0.))
+ {
+ ev_tstamp f = -ev_floor (-v);
+
+ return f - (f == v ? 0 : 1);
+ }
+
+ /* argument too large for an unsigned long? then reduce it */
+ if (ecb_expect_false (v >= shift))
+ {
+ ev_tstamp f;
+
+ if (v == v - 1.)
+ return v; /* very large numbers are assumed to be integer */
+
+ f = shift * ev_floor (v * (1. / shift));
+ return f + ev_floor (v - f);
+ }
+
+ /* fits into an unsigned long */
+ return (unsigned long)v;
+}
+
+#endif
+
+/*****************************************************************************/
+
+#ifdef __linux
+# include <sys/utsname.h>
+#endif
+
+ecb_noinline ecb_cold
+static unsigned int
+ev_linux_version (void)
+{
+#ifdef __linux
+ unsigned int v = 0;
+ struct utsname buf;
+ int i;
+ char *p = buf.release;
+
+ if (uname (&buf))
+ return 0;
+
+ for (i = 3+1; --i; )
+ {
+ unsigned int c = 0;
+
+ for (;;)
+ {
+ if (*p >= '0' && *p <= '9')
+ c = c * 10 + *p++ - '0';
+ else
+ {
+ p += *p == '.';
+ break;
+ }
+ }
+
+ v = (v << 8) | c;
+ }
+
+ return v;
+#else
+ return 0;
+#endif
+}
+
+/*****************************************************************************/
+
+#if EV_AVOID_STDIO
+ecb_noinline ecb_cold
+static void
+ev_printerr (const char *msg)
+{
+ write (STDERR_FILENO, msg, strlen (msg));
+}
+#endif
+
+static void (*syserr_cb)(const char *msg) EV_NOEXCEPT;
+
+ecb_cold
+void
+ev_set_syserr_cb (void (*cb)(const char *msg) EV_NOEXCEPT) EV_NOEXCEPT
+{
+ syserr_cb = cb;
+}
+
+ecb_noinline ecb_cold
+static void
+ev_syserr (const char *msg)
+{
+ if (!msg)
+ msg = "(libev) system error";
+
+ if (syserr_cb)
+ syserr_cb (msg);
+ else
+ {
+#if EV_AVOID_STDIO
+ ev_printerr (msg);
+ ev_printerr (": ");
+ ev_printerr (strerror (errno));
+ ev_printerr ("\n");
+#else
+ perror (msg);
+#endif
+ abort ();
+ }
+}
+
+static void *
+ev_realloc_emul (void *ptr, long size) EV_NOEXCEPT
+{
+ /* some systems, notably openbsd and darwin, fail to properly
+ * implement realloc (x, 0) (as required by both ansi c-89 and
+ * the single unix specification, so work around them here.
+ * recently, also (at least) fedora and debian started breaking it,
+ * despite documenting it otherwise.
+ */
+
+ if (size)
+ return realloc (ptr, size);
+
+ free (ptr);
+ return 0;
+}
+
+static void *(*alloc)(void *ptr, long size) EV_NOEXCEPT = ev_realloc_emul;
+
+ecb_cold
+void
+ev_set_allocator (void *(*cb)(void *ptr, long size) EV_NOEXCEPT) EV_NOEXCEPT
+{
+ alloc = cb;
+}
+
+inline_speed void *
+ev_realloc (void *ptr, long size)
+{
+ ptr = alloc (ptr, size);
+
+ if (!ptr && size)
+ {
+#if EV_AVOID_STDIO
+ ev_printerr ("(libev) memory allocation failed, aborting.\n");
+#else
+ fprintf (stderr, "(libev) cannot allocate %ld bytes, aborting.", size);
+#endif
+ abort ();
+ }
+
+ return ptr;
+}
+
+#define ev_malloc(size) ev_realloc (0, (size))
+#define ev_free(ptr) ev_realloc ((ptr), 0)
+
+/*****************************************************************************/
+
+/* set in reify when reification needed */
+#define EV_ANFD_REIFY 1
+
+/* file descriptor info structure */
+typedef struct
+{
+ WL head;
+ unsigned char events; /* the events watched for */
+ unsigned char reify; /* flag set when this ANFD needs reification (EV_ANFD_REIFY, EV__IOFDSET) */
+ unsigned char emask; /* some backends store the actual kernel mask in here */
+ unsigned char eflags; /* flags field for use by backends */
+#if EV_USE_EPOLL
+ unsigned int egen; /* generation counter to counter epoll bugs */
+#endif
+#if EV_SELECT_IS_WINSOCKET || EV_USE_IOCP
+ SOCKET handle;
+#endif
+#if EV_USE_IOCP
+ OVERLAPPED or, ow;
+#endif
+} ANFD;
+
+/* stores the pending event set for a given watcher */
+typedef struct
+{
+ W w;
+ int events; /* the pending event set for the given watcher */
+} ANPENDING;
+
+#if EV_USE_INOTIFY
+/* hash table entry per inotify-id */
+typedef struct
+{
+ WL head;
+} ANFS;
+#endif
+
+/* Heap Entry */
+#if EV_HEAP_CACHE_AT
+ /* a heap element */
+ typedef struct {
+ ev_tstamp at;
+ WT w;
+ } ANHE;
+
+ #define ANHE_w(he) (he).w /* access watcher, read-write */
+ #define ANHE_at(he) (he).at /* access cached at, read-only */
+ #define ANHE_at_cache(he) (he).at = (he).w->at /* update at from watcher */
+#else
+ /* a heap element */
+ typedef WT ANHE;
+
+ #define ANHE_w(he) (he)
+ #define ANHE_at(he) (he)->at
+ #define ANHE_at_cache(he)
+#endif
+
+#if EV_MULTIPLICITY
+
+ struct ev_loop
+ {
+ ev_tstamp ev_rt_now;
+ #define ev_rt_now ((loop)->ev_rt_now)
+ #define VAR(name,decl) decl;
+ #include "ev_vars.h"
+ #undef VAR
+ };
+ #include "ev_wrap.h"
+
+ static struct ev_loop default_loop_struct;
+ EV_API_DECL struct ev_loop *ev_default_loop_ptr = 0; /* needs to be initialised to make it a definition despite extern */
+
+#else
+
+ EV_API_DECL ev_tstamp ev_rt_now = EV_TS_CONST (0.); /* needs to be initialised to make it a definition despite extern */
+ #define VAR(name,decl) static decl;
+ #include "ev_vars.h"
+ #undef VAR
+
+ static int ev_default_loop_ptr;
+
+#endif
+
+#if EV_FEATURE_API
+# define EV_RELEASE_CB if (ecb_expect_false (release_cb)) release_cb (EV_A)
+# define EV_ACQUIRE_CB if (ecb_expect_false (acquire_cb)) acquire_cb (EV_A)
+# define EV_INVOKE_PENDING invoke_cb (EV_A)
+#else
+# define EV_RELEASE_CB (void)0
+# define EV_ACQUIRE_CB (void)0
+# define EV_INVOKE_PENDING ev_invoke_pending (EV_A)
+#endif
+
+#define EVBREAK_RECURSE 0x80
+
+/*****************************************************************************/
+
+#ifndef EV_HAVE_EV_TIME
+ev_tstamp
+ev_time (void) EV_NOEXCEPT
+{
+#if EV_USE_REALTIME
+ if (ecb_expect_true (have_realtime))
+ {
+ struct timespec ts;
+ clock_gettime (CLOCK_REALTIME, &ts);
+ return EV_TS_GET (ts);
+ }
+#endif
+
+ {
+ struct timeval tv;
+ gettimeofday (&tv, 0);
+ return EV_TV_GET (tv);
+ }
+}
+#endif
+
+inline_size ev_tstamp
+get_clock (void)
+{
+#if EV_USE_MONOTONIC
+ if (ecb_expect_true (have_monotonic))
+ {
+ struct timespec ts;
+ clock_gettime (CLOCK_MONOTONIC, &ts);
+ return EV_TS_GET (ts);
+ }
+#endif
+
+ return ev_time ();
+}
+
+#if EV_MULTIPLICITY
+ev_tstamp
+ev_now (EV_P) EV_NOEXCEPT
+{
+ return ev_rt_now;
+}
+#endif
+
+void
+ev_sleep (ev_tstamp delay) EV_NOEXCEPT
+{
+ if (delay > EV_TS_CONST (0.))
+ {
+#if EV_USE_NANOSLEEP
+ struct timespec ts;
+
+ EV_TS_SET (ts, delay);
+ nanosleep (&ts, 0);
+#elif defined _WIN32
+ /* maybe this should round up, as ms is very low resolution */
+ /* compared to select (µs) or nanosleep (ns) */
+ Sleep ((unsigned long)(EV_TS_TO_MSEC (delay)));
+#else
+ struct timeval tv;
+
+ /* here we rely on sys/time.h + sys/types.h + unistd.h providing select */
+ /* something not guaranteed by newer posix versions, but guaranteed */
+ /* by older ones */
+ EV_TV_SET (tv, delay);
+ select (0, 0, 0, 0, &tv);
+#endif
+ }
+}
+
+/*****************************************************************************/
+
+#define MALLOC_ROUND 4096 /* prefer to allocate in chunks of this size, must be 2**n and >> 4 longs */
+
+/* find a suitable new size for the given array, */
+/* hopefully by rounding to a nice-to-malloc size */
+inline_size int
+array_nextsize (int elem, int cur, int cnt)
+{
+ int ncur = cur + 1;
+
+ do
+ ncur <<= 1;
+ while (cnt > ncur);
+
+ /* if size is large, round to MALLOC_ROUND - 4 * longs to accommodate malloc overhead */
+ if (elem * ncur > MALLOC_ROUND - sizeof (void *) * 4)
+ {
+ ncur *= elem;
+ ncur = (ncur + elem + (MALLOC_ROUND - 1) + sizeof (void *) * 4) & ~(MALLOC_ROUND - 1);
+ ncur = ncur - sizeof (void *) * 4;
+ ncur /= elem;
+ }
+
+ return ncur;
+}
+
+ecb_noinline ecb_cold
+static void *
+array_realloc (int elem, void *base, int *cur, int cnt)
+{
+ *cur = array_nextsize (elem, *cur, cnt);
+ return ev_realloc (base, elem * *cur);
+}
+
+#define array_needsize_noinit(base,offset,count)
+
+#define array_needsize_zerofill(base,offset,count) \
+ memset ((void *)(base + offset), 0, sizeof (*(base)) * (count))
+
+#define array_needsize(type,base,cur,cnt,init) \
+ if (ecb_expect_false ((cnt) > (cur))) \
+ { \
+ ecb_unused int ocur_ = (cur); \
+ (base) = (type *)array_realloc \
+ (sizeof (type), (base), &(cur), (cnt)); \
+ init ((base), ocur_, ((cur) - ocur_)); \
+ }
+
+#if 0
+#define array_slim(type,stem) \
+ if (stem ## max < array_roundsize (stem ## cnt >> 2)) \
+ { \
+ stem ## max = array_roundsize (stem ## cnt >> 1); \
+ base = (type *)ev_realloc (base, sizeof (type) * (stem ## max));\
+ fprintf (stderr, "slimmed down " # stem " to %d\n", stem ## max);/*D*/\
+ }
+#endif
+
+#define array_free(stem, idx) \
+ ev_free (stem ## s idx); stem ## cnt idx = stem ## max idx = 0; stem ## s idx = 0
+
+/*****************************************************************************/
+
+/* dummy callback for pending events */
+ecb_noinline
+static void
+pendingcb (EV_P_ ev_prepare *w, int revents)
+{
+}
+
+ecb_noinline
+void
+ev_feed_event (EV_P_ void *w, int revents) EV_NOEXCEPT
+{
+ W w_ = (W)w;
+ int pri = ABSPRI (w_);
+
+ if (ecb_expect_false (w_->pending))
+ pendings [pri][w_->pending - 1].events |= revents;
+ else
+ {
+ w_->pending = ++pendingcnt [pri];
+ array_needsize (ANPENDING, pendings [pri], pendingmax [pri], w_->pending, array_needsize_noinit);
+ pendings [pri][w_->pending - 1].w = w_;
+ pendings [pri][w_->pending - 1].events = revents;
+ }
+
+ pendingpri = NUMPRI - 1;
+}
+
+inline_speed void
+feed_reverse (EV_P_ W w)
+{
+ array_needsize (W, rfeeds, rfeedmax, rfeedcnt + 1, array_needsize_noinit);
+ rfeeds [rfeedcnt++] = w;
+}
+
+inline_size void
+feed_reverse_done (EV_P_ int revents)
+{
+ do
+ ev_feed_event (EV_A_ rfeeds [--rfeedcnt], revents);
+ while (rfeedcnt);
+}
+
+inline_speed void
+queue_events (EV_P_ W *events, int eventcnt, int type)
+{
+ int i;
+
+ for (i = 0; i < eventcnt; ++i)
+ ev_feed_event (EV_A_ events [i], type);
+}
+
+/*****************************************************************************/
+
+inline_speed void
+fd_event_nocheck (EV_P_ int fd, int revents)
+{
+ ANFD *anfd = anfds + fd;
+ ev_io *w;
+
+ for (w = (ev_io *)anfd->head; w; w = (ev_io *)((WL)w)->next)
+ {
+ int ev = w->events & revents;
+
+ if (ev)
+ ev_feed_event (EV_A_ (W)w, ev);
+ }
+}
+
+/* do not submit kernel events for fds that have reify set */
+/* because that means they changed while we were polling for new events */
+inline_speed void
+fd_event (EV_P_ int fd, int revents)
+{
+ ANFD *anfd = anfds + fd;
+
+ if (ecb_expect_true (!anfd->reify))
+ fd_event_nocheck (EV_A_ fd, revents);
+}
+
+void
+ev_feed_fd_event (EV_P_ int fd, int revents) EV_NOEXCEPT
+{
+ if (fd >= 0 && fd < anfdmax)
+ fd_event_nocheck (EV_A_ fd, revents);
+}
+
+/* make sure the external fd watch events are in-sync */
+/* with the kernel/libev internal state */
+inline_size void
+fd_reify (EV_P)
+{
+ int i;
+
+ /* most backends do not modify the fdchanges list in backend_modfiy.
+ * except io_uring, which has fixed-size buffers which might force us
+ * to handle events in backend_modify, causing fdchanges to be amended,
+ * which could result in an endless loop.
+ * to avoid this, we do not dynamically handle fds that were added
+ * during fd_reify. that means that for those backends, fdchangecnt
+ * might be non-zero during poll, which must cause them to not block.
+ * to not put too much of a burden on other backends, this detail
+ * needs to be handled in the backend.
+ */
+ int changecnt = fdchangecnt;
+
+#if EV_SELECT_IS_WINSOCKET || EV_USE_IOCP
+ for (i = 0; i < changecnt; ++i)
+ {
+ int fd = fdchanges [i];
+ ANFD *anfd = anfds + fd;
+
+ if (anfd->reify & EV__IOFDSET && anfd->head)
+ {
+ SOCKET handle = EV_FD_TO_WIN32_HANDLE (fd);
+
+ if (handle != anfd->handle)
+ {
+ unsigned long arg;
+
+ assert (("libev: only socket fds supported in this configuration", ioctlsocket (handle, FIONREAD, &arg) == 0));
+
+ /* handle changed, but fd didn't - we need to do it in two steps */
+ backend_modify (EV_A_ fd, anfd->events, 0);
+ anfd->events = 0;
+ anfd->handle = handle;
+ }
+ }
+ }
+#endif
+
+ for (i = 0; i < changecnt; ++i)
+ {
+ int fd = fdchanges [i];
+ ANFD *anfd = anfds + fd;
+ ev_io *w;
+
+ unsigned char o_events = anfd->events;
+ unsigned char o_reify = anfd->reify;
+
+ anfd->reify = 0;
+
+ /*if (ecb_expect_true (o_reify & EV_ANFD_REIFY)) probably a deoptimisation */
+ {
+ anfd->events = 0;
+
+ for (w = (ev_io *)anfd->head; w; w = (ev_io *)((WL)w)->next)
+ anfd->events |= (unsigned char)w->events;
+
+ if (o_events != anfd->events)
+ o_reify = EV__IOFDSET; /* actually |= */
+ }
+
+ if (o_reify & EV__IOFDSET)
+ backend_modify (EV_A_ fd, o_events, anfd->events);
+ }
+
+ /* normally, fdchangecnt hasn't changed. if it has, then new fds have been added.
+ * this is a rare case (see beginning comment in this function), so we copy them to the
+ * front and hope the backend handles this case.
+ */
+ if (ecb_expect_false (fdchangecnt != changecnt))
+ memmove (fdchanges, fdchanges + changecnt, (fdchangecnt - changecnt) * sizeof (*fdchanges));
+
+ fdchangecnt -= changecnt;
+}
+
+/* something about the given fd changed */
+inline_size
+void
+fd_change (EV_P_ int fd, int flags)
+{
+ unsigned char reify = anfds [fd].reify;
+ anfds [fd].reify = reify | flags;
+
+ if (ecb_expect_true (!reify))
+ {
+ ++fdchangecnt;
+ array_needsize (int, fdchanges, fdchangemax, fdchangecnt, array_needsize_noinit);
+ fdchanges [fdchangecnt - 1] = fd;
+ }
+}
+
+/* the given fd is invalid/unusable, so make sure it doesn't hurt us anymore */
+inline_speed ecb_cold void
+fd_kill (EV_P_ int fd)
+{
+ ev_io *w;
+
+ while ((w = (ev_io *)anfds [fd].head))
+ {
+ ev_io_stop (EV_A_ w);
+ ev_feed_event (EV_A_ (W)w, EV_ERROR | EV_READ | EV_WRITE);
+ }
+}
+
+/* check whether the given fd is actually valid, for error recovery */
+inline_size ecb_cold int
+fd_valid (int fd)
+{
+#ifdef _WIN32
+ return EV_FD_TO_WIN32_HANDLE (fd) != -1;
+#else
+ return fcntl (fd, F_GETFD) != -1;
+#endif
+}
+
+/* called on EBADF to verify fds */
+ecb_noinline ecb_cold
+static void
+fd_ebadf (EV_P)
+{
+ int fd;
+
+ for (fd = 0; fd < anfdmax; ++fd)
+ if (anfds [fd].events)
+ if (!fd_valid (fd) && errno == EBADF)
+ fd_kill (EV_A_ fd);
+}
+
+/* called on ENOMEM in select/poll to kill some fds and retry */
+ecb_noinline ecb_cold
+static void
+fd_enomem (EV_P)
+{
+ int fd;
+
+ for (fd = anfdmax; fd--; )
+ if (anfds [fd].events)
+ {
+ fd_kill (EV_A_ fd);
+ break;
+ }
+}
+
+/* usually called after fork if backend needs to re-arm all fds from scratch */
+ecb_noinline
+static void
+fd_rearm_all (EV_P)
+{
+ int fd;
+
+ for (fd = 0; fd < anfdmax; ++fd)
+ if (anfds [fd].events)
+ {
+ anfds [fd].events = 0;
+ anfds [fd].emask = 0;
+ fd_change (EV_A_ fd, EV__IOFDSET | EV_ANFD_REIFY);
+ }
+}
+
+/* used to prepare libev internal fd's */
+/* this is not fork-safe */
+inline_speed void
+fd_intern (int fd)
+{
+#ifdef _WIN32
+ unsigned long arg = 1;
+ ioctlsocket (EV_FD_TO_WIN32_HANDLE (fd), FIONBIO, &arg);
+#else
+ fcntl (fd, F_SETFD, FD_CLOEXEC);
+ fcntl (fd, F_SETFL, O_NONBLOCK);
+#endif
+}
+
+/*****************************************************************************/
+
+/*
+ * the heap functions want a real array index. array index 0 is guaranteed to not
+ * be in-use at any time. the first heap entry is at array [HEAP0]. DHEAP gives
+ * the branching factor of the d-tree.
+ */
+
+/*
+ * at the moment we allow libev the luxury of two heaps,
+ * a small-code-size 2-heap one and a ~1.5kb larger 4-heap
+ * which is more cache-efficient.
+ * the difference is about 5% with 50000+ watchers.
+ */
+#if EV_USE_4HEAP
+
+#define DHEAP 4
+#define HEAP0 (DHEAP - 1) /* index of first element in heap */
+#define HPARENT(k) ((((k) - HEAP0 - 1) / DHEAP) + HEAP0)
+#define UPHEAP_DONE(p,k) ((p) == (k))
+
+/* away from the root */
+inline_speed void
+downheap (ANHE *heap, int N, int k)
+{
+ ANHE he = heap [k];
+ ANHE *E = heap + N + HEAP0;
+
+ for (;;)
+ {
+ ev_tstamp minat;
+ ANHE *minpos;
+ ANHE *pos = heap + DHEAP * (k - HEAP0) + HEAP0 + 1;
+
+ /* find minimum child */
+ if (ecb_expect_true (pos + DHEAP - 1 < E))
+ {
+ /* fast path */ (minpos = pos + 0), (minat = ANHE_at (*minpos));
+ if ( minat > ANHE_at (pos [1])) (minpos = pos + 1), (minat = ANHE_at (*minpos));
+ if ( minat > ANHE_at (pos [2])) (minpos = pos + 2), (minat = ANHE_at (*minpos));
+ if ( minat > ANHE_at (pos [3])) (minpos = pos + 3), (minat = ANHE_at (*minpos));
+ }
+ else if (pos < E)
+ {
+ /* slow path */ (minpos = pos + 0), (minat = ANHE_at (*minpos));
+ if (pos + 1 < E && minat > ANHE_at (pos [1])) (minpos = pos + 1), (minat = ANHE_at (*minpos));
+ if (pos + 2 < E && minat > ANHE_at (pos [2])) (minpos = pos + 2), (minat = ANHE_at (*minpos));
+ if (pos + 3 < E && minat > ANHE_at (pos [3])) (minpos = pos + 3), (minat = ANHE_at (*minpos));
+ }
+ else
+ break;
+
+ if (ANHE_at (he) <= minat)
+ break;
+
+ heap [k] = *minpos;
+ ev_active (ANHE_w (*minpos)) = k;
+
+ k = minpos - heap;
+ }
+
+ heap [k] = he;
+ ev_active (ANHE_w (he)) = k;
+}
+
+#else /* not 4HEAP */
+
+#define HEAP0 1
+#define HPARENT(k) ((k) >> 1)
+#define UPHEAP_DONE(p,k) (!(p))
+
+/* away from the root */
+inline_speed void
+downheap (ANHE *heap, int N, int k)
+{
+ ANHE he = heap [k];
+
+ for (;;)
+ {
+ int c = k << 1;
+
+ if (c >= N + HEAP0)
+ break;
+
+ c += c + 1 < N + HEAP0 && ANHE_at (heap [c]) > ANHE_at (heap [c + 1])
+ ? 1 : 0;
+
+ if (ANHE_at (he) <= ANHE_at (heap [c]))
+ break;
+
+ heap [k] = heap [c];
+ ev_active (ANHE_w (heap [k])) = k;
+
+ k = c;
+ }
+
+ heap [k] = he;
+ ev_active (ANHE_w (he)) = k;
+}
+#endif
+
+/* towards the root */
+inline_speed void
+upheap (ANHE *heap, int k)
+{
+ ANHE he = heap [k];
+
+ for (;;)
+ {
+ int p = HPARENT (k);
+
+ if (UPHEAP_DONE (p, k) || ANHE_at (heap [p]) <= ANHE_at (he))
+ break;
+
+ heap [k] = heap [p];
+ ev_active (ANHE_w (heap [k])) = k;
+ k = p;
+ }
+
+ heap [k] = he;
+ ev_active (ANHE_w (he)) = k;
+}
+
+/* move an element suitably so it is in a correct place */
+inline_size void
+adjustheap (ANHE *heap, int N, int k)
+{
+ if (k > HEAP0 && ANHE_at (heap [k]) <= ANHE_at (heap [HPARENT (k)]))
+ upheap (heap, k);
+ else
+ downheap (heap, N, k);
+}
+
+/* rebuild the heap: this function is used only once and executed rarely */
+inline_size void
+reheap (ANHE *heap, int N)
+{
+ int i;
+
+ /* we don't use floyds algorithm, upheap is simpler and is more cache-efficient */
+ /* also, this is easy to implement and correct for both 2-heaps and 4-heaps */
+ for (i = 0; i < N; ++i)
+ upheap (heap, i + HEAP0);
+}
+
+/*****************************************************************************/
+
+/* associate signal watchers to a signal */
+typedef struct
+{
+ EV_ATOMIC_T pending;
+#if EV_MULTIPLICITY
+ EV_P;
+#endif
+ WL head;
+} ANSIG;
+
+static ANSIG signals [EV_NSIG - 1];
+
+/*****************************************************************************/
+
+#if EV_SIGNAL_ENABLE || EV_ASYNC_ENABLE
+
+ecb_noinline ecb_cold
+static void
+evpipe_init (EV_P)
+{
+ if (!ev_is_active (&pipe_w))
+ {
+ int fds [2];
+
+# if EV_USE_EVENTFD
+ fds [0] = -1;
+ fds [1] = eventfd (0, EFD_NONBLOCK | EFD_CLOEXEC);
+ if (fds [1] < 0 && errno == EINVAL)
+ fds [1] = eventfd (0, 0);
+
+ if (fds [1] < 0)
+# endif
+ {
+ while (pipe (fds))
+ ev_syserr ("(libev) error creating signal/async pipe");
+
+ fd_intern (fds [0]);
+ }
+
+ evpipe [0] = fds [0];
+
+ if (evpipe [1] < 0)
+ evpipe [1] = fds [1]; /* first call, set write fd */
+ else
+ {
+ /* on subsequent calls, do not change evpipe [1] */
+ /* so that evpipe_write can always rely on its value. */
+ /* this branch does not do anything sensible on windows, */
+ /* so must not be executed on windows */
+
+ dup2 (fds [1], evpipe [1]);
+ close (fds [1]);
+ }
+
+ fd_intern (evpipe [1]);
+
+ ev_io_set (&pipe_w, evpipe [0] < 0 ? evpipe [1] : evpipe [0], EV_READ);
+ ev_io_start (EV_A_ &pipe_w);
+ ev_unref (EV_A); /* watcher should not keep loop alive */
+ }
+}
+
+inline_speed void
+evpipe_write (EV_P_ EV_ATOMIC_T *flag)
+{
+ ECB_MEMORY_FENCE; /* push out the write before this function was called, acquire flag */
+
+ if (ecb_expect_true (*flag))
+ return;
+
+ *flag = 1;
+ ECB_MEMORY_FENCE_RELEASE; /* make sure flag is visible before the wakeup */
+
+ pipe_write_skipped = 1;
+
+ ECB_MEMORY_FENCE; /* make sure pipe_write_skipped is visible before we check pipe_write_wanted */
+
+ if (pipe_write_wanted)
+ {
+ int old_errno;
+
+ pipe_write_skipped = 0;
+ ECB_MEMORY_FENCE_RELEASE;
+
+ old_errno = errno; /* save errno because write will clobber it */
+
+#if EV_USE_EVENTFD
+ if (evpipe [0] < 0)
+ {
+ uint64_t counter = 1;
+ write (evpipe [1], &counter, sizeof (uint64_t));
+ }
+ else
+#endif
+ {
+#ifdef _WIN32
+ WSABUF buf;
+ DWORD sent;
+ buf.buf = (char *)&buf;
+ buf.len = 1;
+ WSASend (EV_FD_TO_WIN32_HANDLE (evpipe [1]), &buf, 1, &sent, 0, 0, 0);
+#else
+ write (evpipe [1], &(evpipe [1]), 1);
+#endif
+ }
+
+ errno = old_errno;
+ }
+}
+
+/* called whenever the libev signal pipe */
+/* got some events (signal, async) */
+static void
+pipecb (EV_P_ ev_io *iow, int revents)
+{
+ int i;
+
+ if (revents & EV_READ)
+ {
+#if EV_USE_EVENTFD
+ if (evpipe [0] < 0)
+ {
+ uint64_t counter;
+ read (evpipe [1], &counter, sizeof (uint64_t));
+ }
+ else
+#endif
+ {
+ char dummy[4];
+#ifdef _WIN32
+ WSABUF buf;
+ DWORD recvd;
+ DWORD flags = 0;
+ buf.buf = dummy;
+ buf.len = sizeof (dummy);
+ WSARecv (EV_FD_TO_WIN32_HANDLE (evpipe [0]), &buf, 1, &recvd, &flags, 0, 0);
+#else
+ read (evpipe [0], &dummy, sizeof (dummy));
+#endif
+ }
+ }
+
+ pipe_write_skipped = 0;
+
+ ECB_MEMORY_FENCE; /* push out skipped, acquire flags */
+
+#if EV_SIGNAL_ENABLE
+ if (sig_pending)
+ {
+ sig_pending = 0;
+
+ ECB_MEMORY_FENCE;
+
+ for (i = EV_NSIG - 1; i--; )
+ if (ecb_expect_false (signals [i].pending))
+ ev_feed_signal_event (EV_A_ i + 1);
+ }
+#endif
+
+#if EV_ASYNC_ENABLE
+ if (async_pending)
+ {
+ async_pending = 0;
+
+ ECB_MEMORY_FENCE;
+
+ for (i = asynccnt; i--; )
+ if (asyncs [i]->sent)
+ {
+ asyncs [i]->sent = 0;
+ ECB_MEMORY_FENCE_RELEASE;
+ ev_feed_event (EV_A_ asyncs [i], EV_ASYNC);
+ }
+ }
+#endif
+}
+
+/*****************************************************************************/
+
+void
+ev_feed_signal (int signum) EV_NOEXCEPT
+{
+#if EV_MULTIPLICITY
+ EV_P;
+ ECB_MEMORY_FENCE_ACQUIRE;
+ EV_A = signals [signum - 1].loop;
+
+ if (!EV_A)
+ return;
+#endif
+
+ signals [signum - 1].pending = 1;
+ evpipe_write (EV_A_ &sig_pending);
+}
+
+static void
+ev_sighandler (int signum)
+{
+#ifdef _WIN32
+ signal (signum, ev_sighandler);
+#endif
+
+ ev_feed_signal (signum);
+}
+
+ecb_noinline
+void
+ev_feed_signal_event (EV_P_ int signum) EV_NOEXCEPT
+{
+ WL w;
+
+ if (ecb_expect_false (signum <= 0 || signum >= EV_NSIG))
+ return;
+
+ --signum;
+
+#if EV_MULTIPLICITY
+ /* it is permissible to try to feed a signal to the wrong loop */
+ /* or, likely more useful, feeding a signal nobody is waiting for */
+
+ if (ecb_expect_false (signals [signum].loop != EV_A))
+ return;
+#endif
+
+ signals [signum].pending = 0;
+ ECB_MEMORY_FENCE_RELEASE;
+
+ for (w = signals [signum].head; w; w = w->next)
+ ev_feed_event (EV_A_ (W)w, EV_SIGNAL);
+}
+
+#if EV_USE_SIGNALFD
+static void
+sigfdcb (EV_P_ ev_io *iow, int revents)
+{
+ struct signalfd_siginfo si[2], *sip; /* these structs are big */
+
+ for (;;)
+ {
+ ssize_t res = read (sigfd, si, sizeof (si));
+
+ /* not ISO-C, as res might be -1, but works with SuS */
+ for (sip = si; (char *)sip < (char *)si + res; ++sip)
+ ev_feed_signal_event (EV_A_ sip->ssi_signo);
+
+ if (res < (ssize_t)sizeof (si))
+ break;
+ }
+}
+#endif
+
+#endif
+
+/*****************************************************************************/
+
+#if EV_CHILD_ENABLE
+static WL childs [EV_PID_HASHSIZE];
+
+static ev_signal childev;
+
+#ifndef WIFCONTINUED
+# define WIFCONTINUED(status) 0
+#endif
+
+/* handle a single child status event */
+inline_speed void
+child_reap (EV_P_ int chain, int pid, int status)
+{
+ ev_child *w;
+ int traced = WIFSTOPPED (status) || WIFCONTINUED (status);
+
+ for (w = (ev_child *)childs [chain & ((EV_PID_HASHSIZE) - 1)]; w; w = (ev_child *)((WL)w)->next)
+ {
+ if ((w->pid == pid || !w->pid)
+ && (!traced || (w->flags & 1)))
+ {
+ ev_set_priority (w, EV_MAXPRI); /* need to do it *now*, this *must* be the same prio as the signal watcher itself */
+ w->rpid = pid;
+ w->rstatus = status;
+ ev_feed_event (EV_A_ (W)w, EV_CHILD);
+ }
+ }
+}
+
+#ifndef WCONTINUED
+# define WCONTINUED 0
+#endif
+
+/* called on sigchld etc., calls waitpid */
+static void
+childcb (EV_P_ ev_signal *sw, int revents)
+{
+ int pid, status;
+
+ /* some systems define WCONTINUED but then fail to support it (linux 2.4) */
+ if (0 >= (pid = waitpid (-1, &status, WNOHANG | WUNTRACED | WCONTINUED)))
+ if (!WCONTINUED
+ || errno != EINVAL
+ || 0 >= (pid = waitpid (-1, &status, WNOHANG | WUNTRACED)))
+ return;
+
+ /* make sure we are called again until all children have been reaped */
+ /* we need to do it this way so that the callback gets called before we continue */
+ ev_feed_event (EV_A_ (W)sw, EV_SIGNAL);
+
+ child_reap (EV_A_ pid, pid, status);
+ if ((EV_PID_HASHSIZE) > 1)
+ child_reap (EV_A_ 0, pid, status); /* this might trigger a watcher twice, but feed_event catches that */
+}
+
+#endif
+
+/*****************************************************************************/
+
+#if EV_USE_TIMERFD
+
+static void periodics_reschedule (EV_P);
+
+static void
+timerfdcb (EV_P_ ev_io *iow, int revents)
+{
+ struct itimerspec its = { 0 };
+
+ its.it_value.tv_sec = ev_rt_now + (int)MAX_BLOCKTIME2;
+ timerfd_settime (timerfd, TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET, &its, 0);
+
+ ev_rt_now = ev_time ();
+ /* periodics_reschedule only needs ev_rt_now */
+ /* but maybe in the future we want the full treatment. */
+ /*
+ now_floor = EV_TS_CONST (0.);
+ time_update (EV_A_ EV_TSTAMP_HUGE);
+ */
+#if EV_PERIODIC_ENABLE
+ periodics_reschedule (EV_A);
+#endif
+}
+
+ecb_noinline ecb_cold
+static void
+evtimerfd_init (EV_P)
+{
+ if (!ev_is_active (&timerfd_w))
+ {
+ timerfd = timerfd_create (CLOCK_REALTIME, TFD_NONBLOCK | TFD_CLOEXEC);
+
+ if (timerfd >= 0)
+ {
+ fd_intern (timerfd); /* just to be sure */
+
+ ev_io_init (&timerfd_w, timerfdcb, timerfd, EV_READ);
+ ev_set_priority (&timerfd_w, EV_MINPRI);
+ ev_io_start (EV_A_ &timerfd_w);
+ ev_unref (EV_A); /* watcher should not keep loop alive */
+
+ /* (re-) arm timer */
+ timerfdcb (EV_A_ 0, 0);
+ }
+ }
+}
+
+#endif
+
+/*****************************************************************************/
+
+#if EV_USE_IOCP
+# include "ev_iocp.c"
+#endif
+#if EV_USE_PORT
+# include "ev_port.c"
+#endif
+#if EV_USE_KQUEUE
+# include "ev_kqueue.c"
+#endif
+#if EV_USE_EPOLL
+# include "ev_epoll.c"
+#endif
+#if EV_USE_LINUXAIO
+# include "ev_linuxaio.c"
+#endif
+#if EV_USE_IOURING
+# include "ev_iouring.c"
+#endif
+#if EV_USE_POLL
+# include "ev_poll.c"
+#endif
+#if EV_USE_SELECT
+# include "ev_select.c"
+#endif
+
+ecb_cold int
+ev_version_major (void) EV_NOEXCEPT
+{
+ return EV_VERSION_MAJOR;
+}
+
+ecb_cold int
+ev_version_minor (void) EV_NOEXCEPT
+{
+ return EV_VERSION_MINOR;
+}
+
+/* return true if we are running with elevated privileges and should ignore env variables */
+inline_size ecb_cold int
+enable_secure (void)
+{
+#ifdef _WIN32
+ return 0;
+#else
+ return getuid () != geteuid ()
+ || getgid () != getegid ();
+#endif
+}
+
+ecb_cold
+unsigned int
+ev_supported_backends (void) EV_NOEXCEPT
+{
+ unsigned int flags = 0;
+
+ if (EV_USE_PORT ) flags |= EVBACKEND_PORT;
+ if (EV_USE_KQUEUE ) flags |= EVBACKEND_KQUEUE;
+ if (EV_USE_EPOLL ) flags |= EVBACKEND_EPOLL;
+ if (EV_USE_LINUXAIO ) flags |= EVBACKEND_LINUXAIO;
+ if (EV_USE_IOURING && ev_linux_version () >= 0x050601) flags |= EVBACKEND_IOURING; /* 5.6.1+ */
+ if (EV_USE_POLL ) flags |= EVBACKEND_POLL;
+ if (EV_USE_SELECT ) flags |= EVBACKEND_SELECT;
+
+ return flags;
+}
+
+ecb_cold
+unsigned int
+ev_recommended_backends (void) EV_NOEXCEPT
+{
+ unsigned int flags = ev_supported_backends ();
+
+#ifndef __NetBSD__
+ /* kqueue is borked on everything but netbsd apparently */
+ /* it usually doesn't work correctly on anything but sockets and pipes */
+ flags &= ~EVBACKEND_KQUEUE;
+#endif
+#ifdef __APPLE__
+ /* only select works correctly on that "unix-certified" platform */
+ flags &= ~EVBACKEND_KQUEUE; /* horribly broken, even for sockets */
+ flags &= ~EVBACKEND_POLL; /* poll is based on kqueue from 10.5 onwards */
+#endif
+#ifdef __FreeBSD__
+ flags &= ~EVBACKEND_POLL; /* poll return value is unusable (http://forums.freebsd.org/archive/index.php/t-10270.html) */
+#endif
+
+ /* TODO: linuxaio is very experimental */
+#if !EV_RECOMMEND_LINUXAIO
+ flags &= ~EVBACKEND_LINUXAIO;
+#endif
+ /* TODO: linuxaio is super experimental */
+#if !EV_RECOMMEND_IOURING
+ flags &= ~EVBACKEND_IOURING;
+#endif
+
+ return flags;
+}
+
+ecb_cold
+unsigned int
+ev_embeddable_backends (void) EV_NOEXCEPT
+{
+ int flags = EVBACKEND_EPOLL | EVBACKEND_KQUEUE | EVBACKEND_PORT | EVBACKEND_IOURING;
+
+ /* epoll embeddability broken on all linux versions up to at least 2.6.23 */
+ if (ev_linux_version () < 0x020620) /* disable it on linux < 2.6.32 */
+ flags &= ~EVBACKEND_EPOLL;
+
+ /* EVBACKEND_LINUXAIO is theoretically embeddable, but suffers from a performance overhead */
+
+ return flags;
+}
+
+unsigned int
+ev_backend (EV_P) EV_NOEXCEPT
+{
+ return backend;
+}
+
+#if EV_FEATURE_API
+unsigned int
+ev_iteration (EV_P) EV_NOEXCEPT
+{
+ return loop_count;
+}
+
+unsigned int
+ev_depth (EV_P) EV_NOEXCEPT
+{
+ return loop_depth;
+}
+
+void
+ev_set_io_collect_interval (EV_P_ ev_tstamp interval) EV_NOEXCEPT
+{
+ io_blocktime = interval;
+}
+
+void
+ev_set_timeout_collect_interval (EV_P_ ev_tstamp interval) EV_NOEXCEPT
+{
+ timeout_blocktime = interval;
+}
+
+void
+ev_set_userdata (EV_P_ void *data) EV_NOEXCEPT
+{
+ userdata = data;
+}
+
+void *
+ev_userdata (EV_P) EV_NOEXCEPT
+{
+ return userdata;
+}
+
+void
+ev_set_invoke_pending_cb (EV_P_ ev_loop_callback invoke_pending_cb) EV_NOEXCEPT
+{
+ invoke_cb = invoke_pending_cb;
+}
+
+void
+ev_set_loop_release_cb (EV_P_ void (*release)(EV_P) EV_NOEXCEPT, void (*acquire)(EV_P) EV_NOEXCEPT) EV_NOEXCEPT
+{
+ release_cb = release;
+ acquire_cb = acquire;
+}
+#endif
+
+/* initialise a loop structure, must be zero-initialised */
+ecb_noinline ecb_cold
+static void
+loop_init (EV_P_ unsigned int flags) EV_NOEXCEPT
+{
+ if (!backend)
+ {
+ origflags = flags;
+
+#if EV_USE_REALTIME
+ if (!have_realtime)
+ {
+ struct timespec ts;
+
+ if (!clock_gettime (CLOCK_REALTIME, &ts))
+ have_realtime = 1;
+ }
+#endif
+
+#if EV_USE_MONOTONIC
+ if (!have_monotonic)
+ {
+ struct timespec ts;
+
+ if (!clock_gettime (CLOCK_MONOTONIC, &ts))
+ have_monotonic = 1;
+ }
+#endif
+
+ /* pid check not overridable via env */
+#ifndef _WIN32
+ if (flags & EVFLAG_FORKCHECK)
+ curpid = getpid ();
+#endif
+
+ if (!(flags & EVFLAG_NOENV)
+ && !enable_secure ()
+ && getenv ("LIBEV_FLAGS"))
+ flags = atoi (getenv ("LIBEV_FLAGS"));
+
+ ev_rt_now = ev_time ();
+ mn_now = get_clock ();
+ now_floor = mn_now;
+ rtmn_diff = ev_rt_now - mn_now;
+#if EV_FEATURE_API
+ invoke_cb = ev_invoke_pending;
+#endif
+
+ io_blocktime = 0.;
+ timeout_blocktime = 0.;
+ backend = 0;
+ backend_fd = -1;
+ sig_pending = 0;
+#if EV_ASYNC_ENABLE
+ async_pending = 0;
+#endif
+ pipe_write_skipped = 0;
+ pipe_write_wanted = 0;
+ evpipe [0] = -1;
+ evpipe [1] = -1;
+#if EV_USE_INOTIFY
+ fs_fd = flags & EVFLAG_NOINOTIFY ? -1 : -2;
+#endif
+#if EV_USE_SIGNALFD
+ sigfd = flags & EVFLAG_SIGNALFD ? -2 : -1;
+#endif
+#if EV_USE_TIMERFD
+ timerfd = flags & EVFLAG_NOTIMERFD ? -1 : -2;
+#endif
+
+ if (!(flags & EVBACKEND_MASK))
+ flags |= ev_recommended_backends ();
+
+#if EV_USE_IOCP
+ if (!backend && (flags & EVBACKEND_IOCP )) backend = iocp_init (EV_A_ flags);
+#endif
+#if EV_USE_PORT
+ if (!backend && (flags & EVBACKEND_PORT )) backend = port_init (EV_A_ flags);
+#endif
+#if EV_USE_KQUEUE
+ if (!backend && (flags & EVBACKEND_KQUEUE )) backend = kqueue_init (EV_A_ flags);
+#endif
+#if EV_USE_IOURING
+ if (!backend && (flags & EVBACKEND_IOURING )) backend = iouring_init (EV_A_ flags);
+#endif
+#if EV_USE_LINUXAIO
+ if (!backend && (flags & EVBACKEND_LINUXAIO)) backend = linuxaio_init (EV_A_ flags);
+#endif
+#if EV_USE_EPOLL
+ if (!backend && (flags & EVBACKEND_EPOLL )) backend = epoll_init (EV_A_ flags);
+#endif
+#if EV_USE_POLL
+ if (!backend && (flags & EVBACKEND_POLL )) backend = poll_init (EV_A_ flags);
+#endif
+#if EV_USE_SELECT
+ if (!backend && (flags & EVBACKEND_SELECT )) backend = select_init (EV_A_ flags);
+#endif
+
+ ev_prepare_init (&pending_w, pendingcb);
+
+#if EV_SIGNAL_ENABLE || EV_ASYNC_ENABLE
+ ev_init (&pipe_w, pipecb);
+ ev_set_priority (&pipe_w, EV_MAXPRI);
+#endif
+ }
+}
+
+/* free up a loop structure */
+ecb_cold
+void
+ev_loop_destroy (EV_P)
+{
+ int i;
+
+#if EV_MULTIPLICITY
+ /* mimic free (0) */
+ if (!EV_A)
+ return;
+#endif
+
+#if EV_CLEANUP_ENABLE
+ /* queue cleanup watchers (and execute them) */
+ if (ecb_expect_false (cleanupcnt))
+ {
+ queue_events (EV_A_ (W *)cleanups, cleanupcnt, EV_CLEANUP);
+ EV_INVOKE_PENDING;
+ }
+#endif
+
+#if EV_CHILD_ENABLE
+ if (ev_is_default_loop (EV_A) && ev_is_active (&childev))
+ {
+ ev_ref (EV_A); /* child watcher */
+ ev_signal_stop (EV_A_ &childev);
+ }
+#endif
+
+ if (ev_is_active (&pipe_w))
+ {
+ /*ev_ref (EV_A);*/
+ /*ev_io_stop (EV_A_ &pipe_w);*/
+
+ if (evpipe [0] >= 0) EV_WIN32_CLOSE_FD (evpipe [0]);
+ if (evpipe [1] >= 0) EV_WIN32_CLOSE_FD (evpipe [1]);
+ }
+
+#if EV_USE_SIGNALFD
+ if (ev_is_active (&sigfd_w))
+ close (sigfd);
+#endif
+
+#if EV_USE_TIMERFD
+ if (ev_is_active (&timerfd_w))
+ close (timerfd);
+#endif
+
+#if EV_USE_INOTIFY
+ if (fs_fd >= 0)
+ close (fs_fd);
+#endif
+
+ if (backend_fd >= 0)
+ close (backend_fd);
+
+#if EV_USE_IOCP
+ if (backend == EVBACKEND_IOCP ) iocp_destroy (EV_A);
+#endif
+#if EV_USE_PORT
+ if (backend == EVBACKEND_PORT ) port_destroy (EV_A);
+#endif
+#if EV_USE_KQUEUE
+ if (backend == EVBACKEND_KQUEUE ) kqueue_destroy (EV_A);
+#endif
+#if EV_USE_IOURING
+ if (backend == EVBACKEND_IOURING ) iouring_destroy (EV_A);
+#endif
+#if EV_USE_LINUXAIO
+ if (backend == EVBACKEND_LINUXAIO) linuxaio_destroy (EV_A);
+#endif
+#if EV_USE_EPOLL
+ if (backend == EVBACKEND_EPOLL ) epoll_destroy (EV_A);
+#endif
+#if EV_USE_POLL
+ if (backend == EVBACKEND_POLL ) poll_destroy (EV_A);
+#endif
+#if EV_USE_SELECT
+ if (backend == EVBACKEND_SELECT ) select_destroy (EV_A);
+#endif
+
+ for (i = NUMPRI; i--; )
+ {
+ array_free (pending, [i]);
+#if EV_IDLE_ENABLE
+ array_free (idle, [i]);
+#endif
+ }
+
+ ev_free (anfds); anfds = 0; anfdmax = 0;
+
+ /* have to use the microsoft-never-gets-it-right macro */
+ array_free (rfeed, EMPTY);
+ array_free (fdchange, EMPTY);
+ array_free (timer, EMPTY);
+#if EV_PERIODIC_ENABLE
+ array_free (periodic, EMPTY);
+#endif
+#if EV_FORK_ENABLE
+ array_free (fork, EMPTY);
+#endif
+#if EV_CLEANUP_ENABLE
+ array_free (cleanup, EMPTY);
+#endif
+ array_free (prepare, EMPTY);
+ array_free (check, EMPTY);
+#if EV_ASYNC_ENABLE
+ array_free (async, EMPTY);
+#endif
+
+ backend = 0;
+
+#if EV_MULTIPLICITY
+ if (ev_is_default_loop (EV_A))
+#endif
+ ev_default_loop_ptr = 0;
+#if EV_MULTIPLICITY
+ else
+ ev_free (EV_A);
+#endif
+}
+
+#if EV_USE_INOTIFY
+inline_size void infy_fork (EV_P);
+#endif
+
+inline_size void
+loop_fork (EV_P)
+{
+#if EV_USE_PORT
+ if (backend == EVBACKEND_PORT ) port_fork (EV_A);
+#endif
+#if EV_USE_KQUEUE
+ if (backend == EVBACKEND_KQUEUE ) kqueue_fork (EV_A);
+#endif
+#if EV_USE_IOURING
+ if (backend == EVBACKEND_IOURING ) iouring_fork (EV_A);
+#endif
+#if EV_USE_LINUXAIO
+ if (backend == EVBACKEND_LINUXAIO) linuxaio_fork (EV_A);
+#endif
+#if EV_USE_EPOLL
+ if (backend == EVBACKEND_EPOLL ) epoll_fork (EV_A);
+#endif
+#if EV_USE_INOTIFY
+ infy_fork (EV_A);
+#endif
+
+ if (postfork != 2)
+ {
+ #if EV_USE_SIGNALFD
+ /* surprisingly, nothing needs to be done for signalfd, accoridng to docs, it does the right thing on fork */
+ #endif
+
+ #if EV_USE_TIMERFD
+ if (ev_is_active (&timerfd_w))
+ {
+ ev_ref (EV_A);
+ ev_io_stop (EV_A_ &timerfd_w);
+
+ close (timerfd);
+ timerfd = -2;
+
+ evtimerfd_init (EV_A);
+ /* reschedule periodics, in case we missed something */
+ ev_feed_event (EV_A_ &timerfd_w, EV_CUSTOM);
+ }
+ #endif
+
+ #if EV_SIGNAL_ENABLE || EV_ASYNC_ENABLE
+ if (ev_is_active (&pipe_w))
+ {
+ /* pipe_write_wanted must be false now, so modifying fd vars should be safe */
+
+ ev_ref (EV_A);
+ ev_io_stop (EV_A_ &pipe_w);
+
+ if (evpipe [0] >= 0)
+ EV_WIN32_CLOSE_FD (evpipe [0]);
+
+ evpipe_init (EV_A);
+ /* iterate over everything, in case we missed something before */
+ ev_feed_event (EV_A_ &pipe_w, EV_CUSTOM);
+ }
+ #endif
+ }
+
+ postfork = 0;
+}
+
+#if EV_MULTIPLICITY
+
+ecb_cold
+struct ev_loop *
+ev_loop_new (unsigned int flags) EV_NOEXCEPT
+{
+ EV_P = (struct ev_loop *)ev_malloc (sizeof (struct ev_loop));
+
+ memset (EV_A, 0, sizeof (struct ev_loop));
+ loop_init (EV_A_ flags);
+
+ if (ev_backend (EV_A))
+ return EV_A;
+
+ ev_free (EV_A);
+ return 0;
+}
+
+#endif /* multiplicity */
+
+#if EV_VERIFY
+ecb_noinline ecb_cold
+static void
+verify_watcher (EV_P_ W w)
+{
+ assert (("libev: watcher has invalid priority", ABSPRI (w) >= 0 && ABSPRI (w) < NUMPRI));
+
+ if (w->pending)
+ assert (("libev: pending watcher not on pending queue", pendings [ABSPRI (w)][w->pending - 1].w == w));
+}
+
+ecb_noinline ecb_cold
+static void
+verify_heap (EV_P_ ANHE *heap, int N)
+{
+ int i;
+
+ for (i = HEAP0; i < N + HEAP0; ++i)
+ {
+ assert (("libev: active index mismatch in heap", ev_active (ANHE_w (heap [i])) == i));
+ assert (("libev: heap condition violated", i == HEAP0 || ANHE_at (heap [HPARENT (i)]) <= ANHE_at (heap [i])));
+ assert (("libev: heap at cache mismatch", ANHE_at (heap [i]) == ev_at (ANHE_w (heap [i]))));
+
+ verify_watcher (EV_A_ (W)ANHE_w (heap [i]));
+ }
+}
+
+ecb_noinline ecb_cold
+static void
+array_verify (EV_P_ W *ws, int cnt)
+{
+ while (cnt--)
+ {
+ assert (("libev: active index mismatch", ev_active (ws [cnt]) == cnt + 1));
+ verify_watcher (EV_A_ ws [cnt]);
+ }
+}
+#endif
+
+#if EV_FEATURE_API
+void ecb_cold
+ev_verify (EV_P) EV_NOEXCEPT
+{
+#if EV_VERIFY
+ int i;
+ WL w, w2;
+
+ assert (activecnt >= -1);
+
+ assert (fdchangemax >= fdchangecnt);
+ for (i = 0; i < fdchangecnt; ++i)
+ assert (("libev: negative fd in fdchanges", fdchanges [i] >= 0));
+
+ assert (anfdmax >= 0);
+ for (i = 0; i < anfdmax; ++i)
+ {
+ int j = 0;
+
+ for (w = w2 = anfds [i].head; w; w = w->next)
+ {
+ verify_watcher (EV_A_ (W)w);
+
+ if (j++ & 1)
+ {
+ assert (("libev: io watcher list contains a loop", w != w2));
+ w2 = w2->next;
+ }
+
+ assert (("libev: inactive fd watcher on anfd list", ev_active (w) == 1));
+ assert (("libev: fd mismatch between watcher and anfd", ((ev_io *)w)->fd == i));
+ }
+ }
+
+ assert (timermax >= timercnt);
+ verify_heap (EV_A_ timers, timercnt);
+
+#if EV_PERIODIC_ENABLE
+ assert (periodicmax >= periodiccnt);
+ verify_heap (EV_A_ periodics, periodiccnt);
+#endif
+
+ for (i = NUMPRI; i--; )
+ {
+ assert (pendingmax [i] >= pendingcnt [i]);
+#if EV_IDLE_ENABLE
+ assert (idleall >= 0);
+ assert (idlemax [i] >= idlecnt [i]);
+ array_verify (EV_A_ (W *)idles [i], idlecnt [i]);
+#endif
+ }
+
+#if EV_FORK_ENABLE
+ assert (forkmax >= forkcnt);
+ array_verify (EV_A_ (W *)forks, forkcnt);
+#endif
+
+#if EV_CLEANUP_ENABLE
+ assert (cleanupmax >= cleanupcnt);
+ array_verify (EV_A_ (W *)cleanups, cleanupcnt);
+#endif
+
+#if EV_ASYNC_ENABLE
+ assert (asyncmax >= asynccnt);
+ array_verify (EV_A_ (W *)asyncs, asynccnt);
+#endif
+
+#if EV_PREPARE_ENABLE
+ assert (preparemax >= preparecnt);
+ array_verify (EV_A_ (W *)prepares, preparecnt);
+#endif
+
+#if EV_CHECK_ENABLE
+ assert (checkmax >= checkcnt);
+ array_verify (EV_A_ (W *)checks, checkcnt);
+#endif
+
+# if 0
+#if EV_CHILD_ENABLE
+ for (w = (ev_child *)childs [chain & ((EV_PID_HASHSIZE) - 1)]; w; w = (ev_child *)((WL)w)->next)
+ for (signum = EV_NSIG; signum--; ) if (signals [signum].pending)
+#endif
+# endif
+#endif
+}
+#endif
+
+#if EV_MULTIPLICITY
+ecb_cold
+struct ev_loop *
+#else
+int
+#endif
+ev_default_loop (unsigned int flags) EV_NOEXCEPT
+{
+ if (!ev_default_loop_ptr)
+ {
+#if EV_MULTIPLICITY
+ EV_P = ev_default_loop_ptr = &default_loop_struct;
+#else
+ ev_default_loop_ptr = 1;
+#endif
+
+ loop_init (EV_A_ flags);
+
+ if (ev_backend (EV_A))
+ {
+#if EV_CHILD_ENABLE
+ ev_signal_init (&childev, childcb, SIGCHLD);
+ ev_set_priority (&childev, EV_MAXPRI);
+ ev_signal_start (EV_A_ &childev);
+ ev_unref (EV_A); /* child watcher should not keep loop alive */
+#endif
+ }
+ else
+ ev_default_loop_ptr = 0;
+ }
+
+ return ev_default_loop_ptr;
+}
+
+void
+ev_loop_fork (EV_P) EV_NOEXCEPT
+{
+ postfork = 1;
+}
+
+/*****************************************************************************/
+
+void
+ev_invoke (EV_P_ void *w, int revents)
+{
+ EV_CB_INVOKE ((W)w, revents);
+}
+
+unsigned int
+ev_pending_count (EV_P) EV_NOEXCEPT
+{
+ int pri;
+ unsigned int count = 0;
+
+ for (pri = NUMPRI; pri--; )
+ count += pendingcnt [pri];
+
+ return count;
+}
+
+ecb_noinline
+void
+ev_invoke_pending (EV_P)
+{
+ pendingpri = NUMPRI;
+
+ do
+ {
+ --pendingpri;
+
+ /* pendingpri possibly gets modified in the inner loop */
+ while (pendingcnt [pendingpri])
+ {
+ ANPENDING *p = pendings [pendingpri] + --pendingcnt [pendingpri];
+
+ p->w->pending = 0;
+ EV_CB_INVOKE (p->w, p->events);
+ EV_FREQUENT_CHECK;
+ }
+ }
+ while (pendingpri);
+}
+
+#if EV_IDLE_ENABLE
+/* make idle watchers pending. this handles the "call-idle */
+/* only when higher priorities are idle" logic */
+inline_size void
+idle_reify (EV_P)
+{
+ if (ecb_expect_false (idleall))
+ {
+ int pri;
+
+ for (pri = NUMPRI; pri--; )
+ {
+ if (pendingcnt [pri])
+ break;
+
+ if (idlecnt [pri])
+ {
+ queue_events (EV_A_ (W *)idles [pri], idlecnt [pri], EV_IDLE);
+ break;
+ }
+ }
+ }
+}
+#endif
+
+/* make timers pending */
+inline_size void
+timers_reify (EV_P)
+{
+ EV_FREQUENT_CHECK;
+
+ if (timercnt && ANHE_at (timers [HEAP0]) < mn_now)
+ {
+ do
+ {
+ ev_timer *w = (ev_timer *)ANHE_w (timers [HEAP0]);
+
+ /*assert (("libev: inactive timer on timer heap detected", ev_is_active (w)));*/
+
+ /* first reschedule or stop timer */
+ if (w->repeat)
+ {
+ ev_at (w) += w->repeat;
+ if (ev_at (w) < mn_now)
+ ev_at (w) = mn_now;
+
+ assert (("libev: negative ev_timer repeat value found while processing timers", w->repeat > EV_TS_CONST (0.)));
+
+ ANHE_at_cache (timers [HEAP0]);
+ downheap (timers, timercnt, HEAP0);
+ }
+ else
+ ev_timer_stop (EV_A_ w); /* nonrepeating: stop timer */
+
+ EV_FREQUENT_CHECK;
+ feed_reverse (EV_A_ (W)w);
+ }
+ while (timercnt && ANHE_at (timers [HEAP0]) < mn_now);
+
+ feed_reverse_done (EV_A_ EV_TIMER);
+ }
+}
+
+#if EV_PERIODIC_ENABLE
+
+ecb_noinline
+static void
+periodic_recalc (EV_P_ ev_periodic *w)
+{
+ ev_tstamp interval = w->interval > MIN_INTERVAL ? w->interval : MIN_INTERVAL;
+ ev_tstamp at = w->offset + interval * ev_floor ((ev_rt_now - w->offset) / interval);
+
+ /* the above almost always errs on the low side */
+ while (at <= ev_rt_now)
+ {
+ ev_tstamp nat = at + w->interval;
+
+ /* when resolution fails us, we use ev_rt_now */
+ if (ecb_expect_false (nat == at))
+ {
+ at = ev_rt_now;
+ break;
+ }
+
+ at = nat;
+ }
+
+ ev_at (w) = at;
+}
+
+/* make periodics pending */
+inline_size void
+periodics_reify (EV_P)
+{
+ EV_FREQUENT_CHECK;
+
+ while (periodiccnt && ANHE_at (periodics [HEAP0]) < ev_rt_now)
+ {
+ do
+ {
+ ev_periodic *w = (ev_periodic *)ANHE_w (periodics [HEAP0]);
+
+ /*assert (("libev: inactive timer on periodic heap detected", ev_is_active (w)));*/
+
+ /* first reschedule or stop timer */
+ if (w->reschedule_cb)
+ {
+ ev_at (w) = w->reschedule_cb (w, ev_rt_now);
+
+ assert (("libev: ev_periodic reschedule callback returned time in the past", ev_at (w) >= ev_rt_now));
+
+ ANHE_at_cache (periodics [HEAP0]);
+ downheap (periodics, periodiccnt, HEAP0);
+ }
+ else if (w->interval)
+ {
+ periodic_recalc (EV_A_ w);
+ ANHE_at_cache (periodics [HEAP0]);
+ downheap (periodics, periodiccnt, HEAP0);
+ }
+ else
+ ev_periodic_stop (EV_A_ w); /* nonrepeating: stop timer */
+
+ EV_FREQUENT_CHECK;
+ feed_reverse (EV_A_ (W)w);
+ }
+ while (periodiccnt && ANHE_at (periodics [HEAP0]) < ev_rt_now);
+
+ feed_reverse_done (EV_A_ EV_PERIODIC);
+ }
+}
+
+/* simply recalculate all periodics */
+/* TODO: maybe ensure that at least one event happens when jumping forward? */
+ecb_noinline ecb_cold
+static void
+periodics_reschedule (EV_P)
+{
+ int i;
+
+ /* adjust periodics after time jump */
+ for (i = HEAP0; i < periodiccnt + HEAP0; ++i)
+ {
+ ev_periodic *w = (ev_periodic *)ANHE_w (periodics [i]);
+
+ if (w->reschedule_cb)
+ ev_at (w) = w->reschedule_cb (w, ev_rt_now);
+ else if (w->interval)
+ periodic_recalc (EV_A_ w);
+
+ ANHE_at_cache (periodics [i]);
+ }
+
+ reheap (periodics, periodiccnt);
+}
+#endif
+
+/* adjust all timers by a given offset */
+ecb_noinline ecb_cold
+static void
+timers_reschedule (EV_P_ ev_tstamp adjust)
+{
+ int i;
+
+ for (i = 0; i < timercnt; ++i)
+ {
+ ANHE *he = timers + i + HEAP0;
+ ANHE_w (*he)->at += adjust;
+ ANHE_at_cache (*he);
+ }
+}
+
+/* fetch new monotonic and realtime times from the kernel */
+/* also detect if there was a timejump, and act accordingly */
+inline_speed void
+time_update (EV_P_ ev_tstamp max_block)
+{
+#if EV_USE_MONOTONIC
+ if (ecb_expect_true (have_monotonic))
+ {
+ int i;
+ ev_tstamp odiff = rtmn_diff;
+
+ mn_now = get_clock ();
+
+ /* only fetch the realtime clock every 0.5*MIN_TIMEJUMP seconds */
+ /* interpolate in the meantime */
+ if (ecb_expect_true (mn_now - now_floor < EV_TS_CONST (MIN_TIMEJUMP * .5)))
+ {
+ ev_rt_now = rtmn_diff + mn_now;
+ return;
+ }
+
+ now_floor = mn_now;
+ ev_rt_now = ev_time ();
+
+ /* loop a few times, before making important decisions.
+ * on the choice of "4": one iteration isn't enough,
+ * in case we get preempted during the calls to
+ * ev_time and get_clock. a second call is almost guaranteed
+ * to succeed in that case, though. and looping a few more times
+ * doesn't hurt either as we only do this on time-jumps or
+ * in the unlikely event of having been preempted here.
+ */
+ for (i = 4; --i; )
+ {
+ ev_tstamp diff;
+ rtmn_diff = ev_rt_now - mn_now;
+
+ diff = odiff - rtmn_diff;
+
+ if (ecb_expect_true ((diff < EV_TS_CONST (0.) ? -diff : diff) < EV_TS_CONST (MIN_TIMEJUMP)))
+ return; /* all is well */
+
+ ev_rt_now = ev_time ();
+ mn_now = get_clock ();
+ now_floor = mn_now;
+ }
+
+ /* no timer adjustment, as the monotonic clock doesn't jump */
+ /* timers_reschedule (EV_A_ rtmn_diff - odiff) */
+# if EV_PERIODIC_ENABLE
+ periodics_reschedule (EV_A);
+# endif
+ }
+ else
+#endif
+ {
+ ev_rt_now = ev_time ();
+
+ if (ecb_expect_false (mn_now > ev_rt_now || ev_rt_now > mn_now + max_block + EV_TS_CONST (MIN_TIMEJUMP)))
+ {
+ /* adjust timers. this is easy, as the offset is the same for all of them */
+ timers_reschedule (EV_A_ ev_rt_now - mn_now);
+#if EV_PERIODIC_ENABLE
+ periodics_reschedule (EV_A);
+#endif
+ }
+
+ mn_now = ev_rt_now;
+ }
+}
+
+int
+ev_run (EV_P_ int flags)
+{
+#if EV_FEATURE_API
+ ++loop_depth;
+#endif
+
+ assert (("libev: ev_loop recursion during release detected", loop_done != EVBREAK_RECURSE));
+
+ loop_done = EVBREAK_CANCEL;
+
+ EV_INVOKE_PENDING; /* in case we recurse, ensure ordering stays nice and clean */
+
+ do
+ {
+#if EV_VERIFY >= 2
+ ev_verify (EV_A);
+#endif
+
+#ifndef _WIN32
+ if (ecb_expect_false (curpid)) /* penalise the forking check even more */
+ if (ecb_expect_false (getpid () != curpid))
+ {
+ curpid = getpid ();
+ postfork = 1;
+ }
+#endif
+
+#if EV_FORK_ENABLE
+ /* we might have forked, so queue fork handlers */
+ if (ecb_expect_false (postfork))
+ if (forkcnt)
+ {
+ queue_events (EV_A_ (W *)forks, forkcnt, EV_FORK);
+ EV_INVOKE_PENDING;
+ }
+#endif
+
+#if EV_PREPARE_ENABLE
+ /* queue prepare watchers (and execute them) */
+ if (ecb_expect_false (preparecnt))
+ {
+ queue_events (EV_A_ (W *)prepares, preparecnt, EV_PREPARE);
+ EV_INVOKE_PENDING;
+ }
+#endif
+
+ if (ecb_expect_false (loop_done))
+ break;
+
+ /* we might have forked, so reify kernel state if necessary */
+ if (ecb_expect_false (postfork))
+ loop_fork (EV_A);
+
+ /* update fd-related kernel structures */
+ fd_reify (EV_A);
+
+ /* calculate blocking time */
+ {
+ ev_tstamp waittime = 0.;
+ ev_tstamp sleeptime = 0.;
+
+ /* remember old timestamp for io_blocktime calculation */
+ ev_tstamp prev_mn_now = mn_now;
+
+ /* update time to cancel out callback processing overhead */
+ time_update (EV_A_ EV_TS_CONST (EV_TSTAMP_HUGE));
+
+ /* from now on, we want a pipe-wake-up */
+ pipe_write_wanted = 1;
+
+ ECB_MEMORY_FENCE; /* make sure pipe_write_wanted is visible before we check for potential skips */
+
+ if (ecb_expect_true (!(flags & EVRUN_NOWAIT || idleall || !activecnt || pipe_write_skipped)))
+ {
+ waittime = EV_TS_CONST (MAX_BLOCKTIME);
+
+#if EV_USE_TIMERFD
+ /* sleep a lot longer when we can reliably detect timejumps */
+ if (ecb_expect_true (timerfd >= 0))
+ waittime = EV_TS_CONST (MAX_BLOCKTIME2);
+#endif
+#if !EV_PERIODIC_ENABLE
+ /* without periodics but with monotonic clock there is no need */
+ /* for any time jump detection, so sleep longer */
+ if (ecb_expect_true (have_monotonic))
+ waittime = EV_TS_CONST (MAX_BLOCKTIME2);
+#endif
+
+ if (timercnt)
+ {
+ ev_tstamp to = ANHE_at (timers [HEAP0]) - mn_now;
+ if (waittime > to) waittime = to;
+ }
+
+#if EV_PERIODIC_ENABLE
+ if (periodiccnt)
+ {
+ ev_tstamp to = ANHE_at (periodics [HEAP0]) - ev_rt_now;
+ if (waittime > to) waittime = to;
+ }
+#endif
+
+ /* don't let timeouts decrease the waittime below timeout_blocktime */
+ if (ecb_expect_false (waittime < timeout_blocktime))
+ waittime = timeout_blocktime;
+
+ /* now there are two more special cases left, either we have
+ * already-expired timers, so we should not sleep, or we have timers
+ * that expire very soon, in which case we need to wait for a minimum
+ * amount of time for some event loop backends.
+ */
+ if (ecb_expect_false (waittime < backend_mintime))
+ waittime = waittime <= EV_TS_CONST (0.)
+ ? EV_TS_CONST (0.)
+ : backend_mintime;
+
+ /* extra check because io_blocktime is commonly 0 */
+ if (ecb_expect_false (io_blocktime))
+ {
+ sleeptime = io_blocktime - (mn_now - prev_mn_now);
+
+ if (sleeptime > waittime - backend_mintime)
+ sleeptime = waittime - backend_mintime;
+
+ if (ecb_expect_true (sleeptime > EV_TS_CONST (0.)))
+ {
+ ev_sleep (sleeptime);
+ waittime -= sleeptime;
+ }
+ }
+ }
+
+#if EV_FEATURE_API
+ ++loop_count;
+#endif
+ assert ((loop_done = EVBREAK_RECURSE, 1)); /* assert for side effect */
+ backend_poll (EV_A_ waittime);
+ assert ((loop_done = EVBREAK_CANCEL, 1)); /* assert for side effect */
+
+ pipe_write_wanted = 0; /* just an optimisation, no fence needed */
+
+ ECB_MEMORY_FENCE_ACQUIRE;
+ if (pipe_write_skipped)
+ {
+ assert (("libev: pipe_w not active, but pipe not written", ev_is_active (&pipe_w)));
+ ev_feed_event (EV_A_ &pipe_w, EV_CUSTOM);
+ }
+
+ /* update ev_rt_now, do magic */
+ time_update (EV_A_ waittime + sleeptime);
+ }
+
+ /* queue pending timers and reschedule them */
+ timers_reify (EV_A); /* relative timers called last */
+#if EV_PERIODIC_ENABLE
+ periodics_reify (EV_A); /* absolute timers called first */
+#endif
+
+#if EV_IDLE_ENABLE
+ /* queue idle watchers unless other events are pending */
+ idle_reify (EV_A);
+#endif
+
+#if EV_CHECK_ENABLE
+ /* queue check watchers, to be executed first */
+ if (ecb_expect_false (checkcnt))
+ queue_events (EV_A_ (W *)checks, checkcnt, EV_CHECK);
+#endif
+
+ EV_INVOKE_PENDING;
+ }
+ while (ecb_expect_true (
+ activecnt
+ && !loop_done
+ && !(flags & (EVRUN_ONCE | EVRUN_NOWAIT))
+ ));
+
+ if (loop_done == EVBREAK_ONE)
+ loop_done = EVBREAK_CANCEL;
+
+#if EV_FEATURE_API
+ --loop_depth;
+#endif
+
+ return activecnt;
+}
+
+void
+ev_break (EV_P_ int how) EV_NOEXCEPT
+{
+ loop_done = how;
+}
+
+void
+ev_ref (EV_P) EV_NOEXCEPT
+{
+ ++activecnt;
+}
+
+void
+ev_unref (EV_P) EV_NOEXCEPT
+{
+ --activecnt;
+}
+
+void
+ev_now_update (EV_P) EV_NOEXCEPT
+{
+ time_update (EV_A_ EV_TSTAMP_HUGE);
+}
+
+void
+ev_suspend (EV_P) EV_NOEXCEPT
+{
+ ev_now_update (EV_A);
+}
+
+void
+ev_resume (EV_P) EV_NOEXCEPT
+{
+ ev_tstamp mn_prev = mn_now;
+
+ ev_now_update (EV_A);
+ timers_reschedule (EV_A_ mn_now - mn_prev);
+#if EV_PERIODIC_ENABLE
+ /* TODO: really do this? */
+ periodics_reschedule (EV_A);
+#endif
+}
+
+/*****************************************************************************/
+/* singly-linked list management, used when the expected list length is short */
+
+inline_size void
+wlist_add (WL *head, WL elem)
+{
+ elem->next = *head;
+ *head = elem;
+}
+
+inline_size void
+wlist_del (WL *head, WL elem)
+{
+ while (*head)
+ {
+ if (ecb_expect_true (*head == elem))
+ {
+ *head = elem->next;
+ break;
+ }
+
+ head = &(*head)->next;
+ }
+}
+
+/* internal, faster, version of ev_clear_pending */
+inline_speed void
+clear_pending (EV_P_ W w)
+{
+ if (w->pending)
+ {
+ pendings [ABSPRI (w)][w->pending - 1].w = (W)&pending_w;
+ w->pending = 0;
+ }
+}
+
+int
+ev_clear_pending (EV_P_ void *w) EV_NOEXCEPT
+{
+ W w_ = (W)w;
+ int pending = w_->pending;
+
+ if (ecb_expect_true (pending))
+ {
+ ANPENDING *p = pendings [ABSPRI (w_)] + pending - 1;
+ p->w = (W)&pending_w;
+ w_->pending = 0;
+ return p->events;
+ }
+ else
+ return 0;
+}
+
+inline_size void
+pri_adjust (EV_P_ W w)
+{
+ int pri = ev_priority (w);
+ pri = pri < EV_MINPRI ? EV_MINPRI : pri;
+ pri = pri > EV_MAXPRI ? EV_MAXPRI : pri;
+ ev_set_priority (w, pri);
+}
+
+inline_speed void
+ev_start (EV_P_ W w, int active)
+{
+ pri_adjust (EV_A_ w);
+ w->active = active;
+ ev_ref (EV_A);
+}
+
+inline_size void
+ev_stop (EV_P_ W w)
+{
+ ev_unref (EV_A);
+ w->active = 0;
+}
+
+/*****************************************************************************/
+
+ecb_noinline
+void
+ev_io_start (EV_P_ ev_io *w) EV_NOEXCEPT
+{
+ int fd = w->fd;
+
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ assert (("libev: ev_io_start called with negative fd", fd >= 0));
+ assert (("libev: ev_io_start called with illegal event mask", !(w->events & ~(EV__IOFDSET | EV_READ | EV_WRITE))));
+
+#if EV_VERIFY >= 2
+ assert (("libev: ev_io_start called on watcher with invalid fd", fd_valid (fd)));
+#endif
+ EV_FREQUENT_CHECK;
+
+ ev_start (EV_A_ (W)w, 1);
+ array_needsize (ANFD, anfds, anfdmax, fd + 1, array_needsize_zerofill);
+ wlist_add (&anfds[fd].head, (WL)w);
+
+ /* common bug, apparently */
+ assert (("libev: ev_io_start called with corrupted watcher", ((WL)w)->next != (WL)w));
+
+ fd_change (EV_A_ fd, w->events & EV__IOFDSET | EV_ANFD_REIFY);
+ w->events &= ~EV__IOFDSET;
+
+ EV_FREQUENT_CHECK;
+}
+
+ecb_noinline
+void
+ev_io_stop (EV_P_ ev_io *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ assert (("libev: ev_io_stop called with illegal fd (must stay constant after start!)", w->fd >= 0 && w->fd < anfdmax));
+
+#if EV_VERIFY >= 2
+ assert (("libev: ev_io_stop called on watcher with invalid fd", fd_valid (w->fd)));
+#endif
+ EV_FREQUENT_CHECK;
+
+ wlist_del (&anfds[w->fd].head, (WL)w);
+ ev_stop (EV_A_ (W)w);
+
+ fd_change (EV_A_ w->fd, EV_ANFD_REIFY);
+
+ EV_FREQUENT_CHECK;
+}
+
+ecb_noinline
+void
+ev_timer_start (EV_P_ ev_timer *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ ev_at (w) += mn_now;
+
+ assert (("libev: ev_timer_start called with negative timer repeat value", w->repeat >= 0.));
+
+ EV_FREQUENT_CHECK;
+
+ ++timercnt;
+ ev_start (EV_A_ (W)w, timercnt + HEAP0 - 1);
+ array_needsize (ANHE, timers, timermax, ev_active (w) + 1, array_needsize_noinit);
+ ANHE_w (timers [ev_active (w)]) = (WT)w;
+ ANHE_at_cache (timers [ev_active (w)]);
+ upheap (timers, ev_active (w));
+
+ EV_FREQUENT_CHECK;
+
+ /*assert (("libev: internal timer heap corruption", timers [ev_active (w)] == (WT)w));*/
+}
+
+ecb_noinline
+void
+ev_timer_stop (EV_P_ ev_timer *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ {
+ int active = ev_active (w);
+
+ assert (("libev: internal timer heap corruption", ANHE_w (timers [active]) == (WT)w));
+
+ --timercnt;
+
+ if (ecb_expect_true (active < timercnt + HEAP0))
+ {
+ timers [active] = timers [timercnt + HEAP0];
+ adjustheap (timers, timercnt, active);
+ }
+ }
+
+ ev_at (w) -= mn_now;
+
+ ev_stop (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+}
+
+ecb_noinline
+void
+ev_timer_again (EV_P_ ev_timer *w) EV_NOEXCEPT
+{
+ EV_FREQUENT_CHECK;
+
+ clear_pending (EV_A_ (W)w);
+
+ if (ev_is_active (w))
+ {
+ if (w->repeat)
+ {
+ ev_at (w) = mn_now + w->repeat;
+ ANHE_at_cache (timers [ev_active (w)]);
+ adjustheap (timers, timercnt, ev_active (w));
+ }
+ else
+ ev_timer_stop (EV_A_ w);
+ }
+ else if (w->repeat)
+ {
+ ev_at (w) = w->repeat;
+ ev_timer_start (EV_A_ w);
+ }
+
+ EV_FREQUENT_CHECK;
+}
+
+ev_tstamp
+ev_timer_remaining (EV_P_ ev_timer *w) EV_NOEXCEPT
+{
+ return ev_at (w) - (ev_is_active (w) ? mn_now : EV_TS_CONST (0.));
+}
+
+#if EV_PERIODIC_ENABLE
+ecb_noinline
+void
+ev_periodic_start (EV_P_ ev_periodic *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+#if EV_USE_TIMERFD
+ if (timerfd == -2)
+ evtimerfd_init (EV_A);
+#endif
+
+ if (w->reschedule_cb)
+ ev_at (w) = w->reschedule_cb (w, ev_rt_now);
+ else if (w->interval)
+ {
+ assert (("libev: ev_periodic_start called with negative interval value", w->interval >= 0.));
+ periodic_recalc (EV_A_ w);
+ }
+ else
+ ev_at (w) = w->offset;
+
+ EV_FREQUENT_CHECK;
+
+ ++periodiccnt;
+ ev_start (EV_A_ (W)w, periodiccnt + HEAP0 - 1);
+ array_needsize (ANHE, periodics, periodicmax, ev_active (w) + 1, array_needsize_noinit);
+ ANHE_w (periodics [ev_active (w)]) = (WT)w;
+ ANHE_at_cache (periodics [ev_active (w)]);
+ upheap (periodics, ev_active (w));
+
+ EV_FREQUENT_CHECK;
+
+ /*assert (("libev: internal periodic heap corruption", ANHE_w (periodics [ev_active (w)]) == (WT)w));*/
+}
+
+ecb_noinline
+void
+ev_periodic_stop (EV_P_ ev_periodic *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ {
+ int active = ev_active (w);
+
+ assert (("libev: internal periodic heap corruption", ANHE_w (periodics [active]) == (WT)w));
+
+ --periodiccnt;
+
+ if (ecb_expect_true (active < periodiccnt + HEAP0))
+ {
+ periodics [active] = periodics [periodiccnt + HEAP0];
+ adjustheap (periodics, periodiccnt, active);
+ }
+ }
+
+ ev_stop (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+}
+
+ecb_noinline
+void
+ev_periodic_again (EV_P_ ev_periodic *w) EV_NOEXCEPT
+{
+ /* TODO: use adjustheap and recalculation */
+ ev_periodic_stop (EV_A_ w);
+ ev_periodic_start (EV_A_ w);
+}
+#endif
+
+#ifndef SA_RESTART
+# define SA_RESTART 0
+#endif
+
+#if EV_SIGNAL_ENABLE
+
+ecb_noinline
+void
+ev_signal_start (EV_P_ ev_signal *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ assert (("libev: ev_signal_start called with illegal signal number", w->signum > 0 && w->signum < EV_NSIG));
+
+#if EV_MULTIPLICITY
+ assert (("libev: a signal must not be attached to two different loops",
+ !signals [w->signum - 1].loop || signals [w->signum - 1].loop == loop));
+
+ signals [w->signum - 1].loop = EV_A;
+ ECB_MEMORY_FENCE_RELEASE;
+#endif
+
+ EV_FREQUENT_CHECK;
+
+#if EV_USE_SIGNALFD
+ if (sigfd == -2)
+ {
+ sigfd = signalfd (-1, &sigfd_set, SFD_NONBLOCK | SFD_CLOEXEC);
+ if (sigfd < 0 && errno == EINVAL)
+ sigfd = signalfd (-1, &sigfd_set, 0); /* retry without flags */
+
+ if (sigfd >= 0)
+ {
+ fd_intern (sigfd); /* doing it twice will not hurt */
+
+ sigemptyset (&sigfd_set);
+
+ ev_io_init (&sigfd_w, sigfdcb, sigfd, EV_READ);
+ ev_set_priority (&sigfd_w, EV_MAXPRI);
+ ev_io_start (EV_A_ &sigfd_w);
+ ev_unref (EV_A); /* signalfd watcher should not keep loop alive */
+ }
+ }
+
+ if (sigfd >= 0)
+ {
+ /* TODO: check .head */
+ sigaddset (&sigfd_set, w->signum);
+ sigprocmask (SIG_BLOCK, &sigfd_set, 0);
+
+ signalfd (sigfd, &sigfd_set, 0);
+ }
+#endif
+
+ ev_start (EV_A_ (W)w, 1);
+ wlist_add (&signals [w->signum - 1].head, (WL)w);
+
+ if (!((WL)w)->next)
+# if EV_USE_SIGNALFD
+ if (sigfd < 0) /*TODO*/
+# endif
+ {
+# ifdef _WIN32
+ evpipe_init (EV_A);
+
+ signal (w->signum, ev_sighandler);
+# else
+ struct sigaction sa;
+
+ evpipe_init (EV_A);
+
+ sa.sa_handler = ev_sighandler;
+ sigfillset (&sa.sa_mask);
+ sa.sa_flags = SA_RESTART; /* if restarting works we save one iteration */
+ sigaction (w->signum, &sa, 0);
+
+ if (origflags & EVFLAG_NOSIGMASK)
+ {
+ sigemptyset (&sa.sa_mask);
+ sigaddset (&sa.sa_mask, w->signum);
+ sigprocmask (SIG_UNBLOCK, &sa.sa_mask, 0);
+ }
+#endif
+ }
+
+ EV_FREQUENT_CHECK;
+}
+
+ecb_noinline
+void
+ev_signal_stop (EV_P_ ev_signal *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ wlist_del (&signals [w->signum - 1].head, (WL)w);
+ ev_stop (EV_A_ (W)w);
+
+ if (!signals [w->signum - 1].head)
+ {
+#if EV_MULTIPLICITY
+ signals [w->signum - 1].loop = 0; /* unattach from signal */
+#endif
+#if EV_USE_SIGNALFD
+ if (sigfd >= 0)
+ {
+ sigset_t ss;
+
+ sigemptyset (&ss);
+ sigaddset (&ss, w->signum);
+ sigdelset (&sigfd_set, w->signum);
+
+ signalfd (sigfd, &sigfd_set, 0);
+ sigprocmask (SIG_UNBLOCK, &ss, 0);
+ }
+ else
+#endif
+ signal (w->signum, SIG_DFL);
+ }
+
+ EV_FREQUENT_CHECK;
+}
+
+#endif
+
+#if EV_CHILD_ENABLE
+
+void
+ev_child_start (EV_P_ ev_child *w) EV_NOEXCEPT
+{
+#if EV_MULTIPLICITY
+ assert (("libev: child watchers are only supported in the default loop", loop == ev_default_loop_ptr));
+#endif
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ ev_start (EV_A_ (W)w, 1);
+ wlist_add (&childs [w->pid & ((EV_PID_HASHSIZE) - 1)], (WL)w);
+
+ EV_FREQUENT_CHECK;
+}
+
+void
+ev_child_stop (EV_P_ ev_child *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ wlist_del (&childs [w->pid & ((EV_PID_HASHSIZE) - 1)], (WL)w);
+ ev_stop (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+}
+
+#endif
+
+#if EV_STAT_ENABLE
+
+# ifdef _WIN32
+# undef lstat
+# define lstat(a,b) _stati64 (a,b)
+# endif
+
+#define DEF_STAT_INTERVAL 5.0074891
+#define NFS_STAT_INTERVAL 30.1074891 /* for filesystems potentially failing inotify */
+#define MIN_STAT_INTERVAL 0.1074891
+
+ecb_noinline static void stat_timer_cb (EV_P_ ev_timer *w_, int revents);
+
+#if EV_USE_INOTIFY
+
+/* the * 2 is to allow for alignment padding, which for some reason is >> 8 */
+# define EV_INOTIFY_BUFSIZE (sizeof (struct inotify_event) * 2 + NAME_MAX)
+
+ecb_noinline
+static void
+infy_add (EV_P_ ev_stat *w)
+{
+ w->wd = inotify_add_watch (fs_fd, w->path,
+ IN_ATTRIB | IN_DELETE_SELF | IN_MOVE_SELF | IN_MODIFY
+ | IN_CREATE | IN_DELETE | IN_MOVED_FROM | IN_MOVED_TO
+ | IN_DONT_FOLLOW | IN_MASK_ADD);
+
+ if (w->wd >= 0)
+ {
+ struct statfs sfs;
+
+ /* now local changes will be tracked by inotify, but remote changes won't */
+ /* unless the filesystem is known to be local, we therefore still poll */
+ /* also do poll on <2.6.25, but with normal frequency */
+
+ if (!fs_2625)
+ w->timer.repeat = w->interval ? w->interval : DEF_STAT_INTERVAL;
+ else if (!statfs (w->path, &sfs)
+ && (sfs.f_type == 0x1373 /* devfs */
+ || sfs.f_type == 0x4006 /* fat */
+ || sfs.f_type == 0x4d44 /* msdos */
+ || sfs.f_type == 0xEF53 /* ext2/3 */
+ || sfs.f_type == 0x72b6 /* jffs2 */
+ || sfs.f_type == 0x858458f6 /* ramfs */
+ || sfs.f_type == 0x5346544e /* ntfs */
+ || sfs.f_type == 0x3153464a /* jfs */
+ || sfs.f_type == 0x9123683e /* btrfs */
+ || sfs.f_type == 0x52654973 /* reiser3 */
+ || sfs.f_type == 0x01021994 /* tmpfs */
+ || sfs.f_type == 0x58465342 /* xfs */))
+ w->timer.repeat = 0.; /* filesystem is local, kernel new enough */
+ else
+ w->timer.repeat = w->interval ? w->interval : NFS_STAT_INTERVAL; /* remote, use reduced frequency */
+ }
+ else
+ {
+ /* can't use inotify, continue to stat */
+ w->timer.repeat = w->interval ? w->interval : DEF_STAT_INTERVAL;
+
+ /* if path is not there, monitor some parent directory for speedup hints */
+ /* note that exceeding the hardcoded path limit is not a correctness issue, */
+ /* but an efficiency issue only */
+ if ((errno == ENOENT || errno == EACCES) && strlen (w->path) < 4096)
+ {
+ char path [4096];
+ strcpy (path, w->path);
+
+ do
+ {
+ int mask = IN_MASK_ADD | IN_DELETE_SELF | IN_MOVE_SELF
+ | (errno == EACCES ? IN_ATTRIB : IN_CREATE | IN_MOVED_TO);
+
+ char *pend = strrchr (path, '/');
+
+ if (!pend || pend == path)
+ break;
+
+ *pend = 0;
+ w->wd = inotify_add_watch (fs_fd, path, mask);
+ }
+ while (w->wd < 0 && (errno == ENOENT || errno == EACCES));
+ }
+ }
+
+ if (w->wd >= 0)
+ wlist_add (&fs_hash [w->wd & ((EV_INOTIFY_HASHSIZE) - 1)].head, (WL)w);
+
+ /* now re-arm timer, if required */
+ if (ev_is_active (&w->timer)) ev_ref (EV_A);
+ ev_timer_again (EV_A_ &w->timer);
+ if (ev_is_active (&w->timer)) ev_unref (EV_A);
+}
+
+ecb_noinline
+static void
+infy_del (EV_P_ ev_stat *w)
+{
+ int slot;
+ int wd = w->wd;
+
+ if (wd < 0)
+ return;
+
+ w->wd = -2;
+ slot = wd & ((EV_INOTIFY_HASHSIZE) - 1);
+ wlist_del (&fs_hash [slot].head, (WL)w);
+
+ /* remove this watcher, if others are watching it, they will rearm */
+ inotify_rm_watch (fs_fd, wd);
+}
+
+ecb_noinline
+static void
+infy_wd (EV_P_ int slot, int wd, struct inotify_event *ev)
+{
+ if (slot < 0)
+ /* overflow, need to check for all hash slots */
+ for (slot = 0; slot < (EV_INOTIFY_HASHSIZE); ++slot)
+ infy_wd (EV_A_ slot, wd, ev);
+ else
+ {
+ WL w_;
+
+ for (w_ = fs_hash [slot & ((EV_INOTIFY_HASHSIZE) - 1)].head; w_; )
+ {
+ ev_stat *w = (ev_stat *)w_;
+ w_ = w_->next; /* lets us remove this watcher and all before it */
+
+ if (w->wd == wd || wd == -1)
+ {
+ if (ev->mask & (IN_IGNORED | IN_UNMOUNT | IN_DELETE_SELF))
+ {
+ wlist_del (&fs_hash [slot & ((EV_INOTIFY_HASHSIZE) - 1)].head, (WL)w);
+ w->wd = -1;
+ infy_add (EV_A_ w); /* re-add, no matter what */
+ }
+
+ stat_timer_cb (EV_A_ &w->timer, 0);
+ }
+ }
+ }
+}
+
+static void
+infy_cb (EV_P_ ev_io *w, int revents)
+{
+ char buf [EV_INOTIFY_BUFSIZE];
+ int ofs;
+ int len = read (fs_fd, buf, sizeof (buf));
+
+ for (ofs = 0; ofs < len; )
+ {
+ struct inotify_event *ev = (struct inotify_event *)(buf + ofs);
+ infy_wd (EV_A_ ev->wd, ev->wd, ev);
+ ofs += sizeof (struct inotify_event) + ev->len;
+ }
+}
+
+inline_size ecb_cold
+void
+ev_check_2625 (EV_P)
+{
+ /* kernels < 2.6.25 are borked
+ * http://www.ussg.indiana.edu/hypermail/linux/kernel/0711.3/1208.html
+ */
+ if (ev_linux_version () < 0x020619)
+ return;
+
+ fs_2625 = 1;
+}
+
+inline_size int
+infy_newfd (void)
+{
+#if defined IN_CLOEXEC && defined IN_NONBLOCK
+ int fd = inotify_init1 (IN_CLOEXEC | IN_NONBLOCK);
+ if (fd >= 0)
+ return fd;
+#endif
+ return inotify_init ();
+}
+
+inline_size void
+infy_init (EV_P)
+{
+ if (fs_fd != -2)
+ return;
+
+ fs_fd = -1;
+
+ ev_check_2625 (EV_A);
+
+ fs_fd = infy_newfd ();
+
+ if (fs_fd >= 0)
+ {
+ fd_intern (fs_fd);
+ ev_io_init (&fs_w, infy_cb, fs_fd, EV_READ);
+ ev_set_priority (&fs_w, EV_MAXPRI);
+ ev_io_start (EV_A_ &fs_w);
+ ev_unref (EV_A);
+ }
+}
+
+inline_size void
+infy_fork (EV_P)
+{
+ int slot;
+
+ if (fs_fd < 0)
+ return;
+
+ ev_ref (EV_A);
+ ev_io_stop (EV_A_ &fs_w);
+ close (fs_fd);
+ fs_fd = infy_newfd ();
+
+ if (fs_fd >= 0)
+ {
+ fd_intern (fs_fd);
+ ev_io_set (&fs_w, fs_fd, EV_READ);
+ ev_io_start (EV_A_ &fs_w);
+ ev_unref (EV_A);
+ }
+
+ for (slot = 0; slot < (EV_INOTIFY_HASHSIZE); ++slot)
+ {
+ WL w_ = fs_hash [slot].head;
+ fs_hash [slot].head = 0;
+
+ while (w_)
+ {
+ ev_stat *w = (ev_stat *)w_;
+ w_ = w_->next; /* lets us add this watcher */
+
+ w->wd = -1;
+
+ if (fs_fd >= 0)
+ infy_add (EV_A_ w); /* re-add, no matter what */
+ else
+ {
+ w->timer.repeat = w->interval ? w->interval : DEF_STAT_INTERVAL;
+ if (ev_is_active (&w->timer)) ev_ref (EV_A);
+ ev_timer_again (EV_A_ &w->timer);
+ if (ev_is_active (&w->timer)) ev_unref (EV_A);
+ }
+ }
+ }
+}
+
+#endif
+
+#ifdef _WIN32
+# define EV_LSTAT(p,b) _stati64 (p, b)
+#else
+# define EV_LSTAT(p,b) lstat (p, b)
+#endif
+
+void
+ev_stat_stat (EV_P_ ev_stat *w) EV_NOEXCEPT
+{
+ if (lstat (w->path, &w->attr) < 0)
+ w->attr.st_nlink = 0;
+ else if (!w->attr.st_nlink)
+ w->attr.st_nlink = 1;
+}
+
+ecb_noinline
+static void
+stat_timer_cb (EV_P_ ev_timer *w_, int revents)
+{
+ ev_stat *w = (ev_stat *)(((char *)w_) - offsetof (ev_stat, timer));
+
+ ev_statdata prev = w->attr;
+ ev_stat_stat (EV_A_ w);
+
+ /* memcmp doesn't work on netbsd, they.... do stuff to their struct stat */
+ if (
+ prev.st_dev != w->attr.st_dev
+ || prev.st_ino != w->attr.st_ino
+ || prev.st_mode != w->attr.st_mode
+ || prev.st_nlink != w->attr.st_nlink
+ || prev.st_uid != w->attr.st_uid
+ || prev.st_gid != w->attr.st_gid
+ || prev.st_rdev != w->attr.st_rdev
+ || prev.st_size != w->attr.st_size
+ || prev.st_atime != w->attr.st_atime
+ || prev.st_mtime != w->attr.st_mtime
+ || prev.st_ctime != w->attr.st_ctime
+ ) {
+ /* we only update w->prev on actual differences */
+ /* in case we test more often than invoke the callback, */
+ /* to ensure that prev is always different to attr */
+ w->prev = prev;
+
+ #if EV_USE_INOTIFY
+ if (fs_fd >= 0)
+ {
+ infy_del (EV_A_ w);
+ infy_add (EV_A_ w);
+ ev_stat_stat (EV_A_ w); /* avoid race... */
+ }
+ #endif
+
+ ev_feed_event (EV_A_ w, EV_STAT);
+ }
+}
+
+void
+ev_stat_start (EV_P_ ev_stat *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ ev_stat_stat (EV_A_ w);
+
+ if (w->interval < MIN_STAT_INTERVAL && w->interval)
+ w->interval = MIN_STAT_INTERVAL;
+
+ ev_timer_init (&w->timer, stat_timer_cb, 0., w->interval ? w->interval : DEF_STAT_INTERVAL);
+ ev_set_priority (&w->timer, ev_priority (w));
+
+#if EV_USE_INOTIFY
+ infy_init (EV_A);
+
+ if (fs_fd >= 0)
+ infy_add (EV_A_ w);
+ else
+#endif
+ {
+ ev_timer_again (EV_A_ &w->timer);
+ ev_unref (EV_A);
+ }
+
+ ev_start (EV_A_ (W)w, 1);
+
+ EV_FREQUENT_CHECK;
+}
+
+void
+ev_stat_stop (EV_P_ ev_stat *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+#if EV_USE_INOTIFY
+ infy_del (EV_A_ w);
+#endif
+
+ if (ev_is_active (&w->timer))
+ {
+ ev_ref (EV_A);
+ ev_timer_stop (EV_A_ &w->timer);
+ }
+
+ ev_stop (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+}
+#endif
+
+#if EV_IDLE_ENABLE
+void
+ev_idle_start (EV_P_ ev_idle *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ pri_adjust (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+
+ {
+ int active = ++idlecnt [ABSPRI (w)];
+
+ ++idleall;
+ ev_start (EV_A_ (W)w, active);
+
+ array_needsize (ev_idle *, idles [ABSPRI (w)], idlemax [ABSPRI (w)], active, array_needsize_noinit);
+ idles [ABSPRI (w)][active - 1] = w;
+ }
+
+ EV_FREQUENT_CHECK;
+}
+
+void
+ev_idle_stop (EV_P_ ev_idle *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ {
+ int active = ev_active (w);
+
+ idles [ABSPRI (w)][active - 1] = idles [ABSPRI (w)][--idlecnt [ABSPRI (w)]];
+ ev_active (idles [ABSPRI (w)][active - 1]) = active;
+
+ ev_stop (EV_A_ (W)w);
+ --idleall;
+ }
+
+ EV_FREQUENT_CHECK;
+}
+#endif
+
+#if EV_PREPARE_ENABLE
+void
+ev_prepare_start (EV_P_ ev_prepare *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ ev_start (EV_A_ (W)w, ++preparecnt);
+ array_needsize (ev_prepare *, prepares, preparemax, preparecnt, array_needsize_noinit);
+ prepares [preparecnt - 1] = w;
+
+ EV_FREQUENT_CHECK;
+}
+
+void
+ev_prepare_stop (EV_P_ ev_prepare *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ {
+ int active = ev_active (w);
+
+ prepares [active - 1] = prepares [--preparecnt];
+ ev_active (prepares [active - 1]) = active;
+ }
+
+ ev_stop (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+}
+#endif
+
+#if EV_CHECK_ENABLE
+void
+ev_check_start (EV_P_ ev_check *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ ev_start (EV_A_ (W)w, ++checkcnt);
+ array_needsize (ev_check *, checks, checkmax, checkcnt, array_needsize_noinit);
+ checks [checkcnt - 1] = w;
+
+ EV_FREQUENT_CHECK;
+}
+
+void
+ev_check_stop (EV_P_ ev_check *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ {
+ int active = ev_active (w);
+
+ checks [active - 1] = checks [--checkcnt];
+ ev_active (checks [active - 1]) = active;
+ }
+
+ ev_stop (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+}
+#endif
+
+#if EV_EMBED_ENABLE
+ecb_noinline
+void
+ev_embed_sweep (EV_P_ ev_embed *w) EV_NOEXCEPT
+{
+ ev_run (w->other, EVRUN_NOWAIT);
+}
+
+static void
+embed_io_cb (EV_P_ ev_io *io, int revents)
+{
+ ev_embed *w = (ev_embed *)(((char *)io) - offsetof (ev_embed, io));
+
+ if (ev_cb (w))
+ ev_feed_event (EV_A_ (W)w, EV_EMBED);
+ else
+ ev_run (w->other, EVRUN_NOWAIT);
+}
+
+static void
+embed_prepare_cb (EV_P_ ev_prepare *prepare, int revents)
+{
+ ev_embed *w = (ev_embed *)(((char *)prepare) - offsetof (ev_embed, prepare));
+
+ {
+ EV_P = w->other;
+
+ while (fdchangecnt)
+ {
+ fd_reify (EV_A);
+ ev_run (EV_A_ EVRUN_NOWAIT);
+ }
+ }
+}
+
+#if EV_FORK_ENABLE
+static void
+embed_fork_cb (EV_P_ ev_fork *fork_w, int revents)
+{
+ ev_embed *w = (ev_embed *)(((char *)fork_w) - offsetof (ev_embed, fork));
+
+ ev_embed_stop (EV_A_ w);
+
+ {
+ EV_P = w->other;
+
+ ev_loop_fork (EV_A);
+ ev_run (EV_A_ EVRUN_NOWAIT);
+ }
+
+ ev_embed_start (EV_A_ w);
+}
+#endif
+
+#if 0
+static void
+embed_idle_cb (EV_P_ ev_idle *idle, int revents)
+{
+ ev_idle_stop (EV_A_ idle);
+}
+#endif
+
+void
+ev_embed_start (EV_P_ ev_embed *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ {
+ EV_P = w->other;
+ assert (("libev: loop to be embedded is not embeddable", backend & ev_embeddable_backends ()));
+ ev_io_init (&w->io, embed_io_cb, backend_fd, EV_READ);
+ }
+
+ EV_FREQUENT_CHECK;
+
+ ev_set_priority (&w->io, ev_priority (w));
+ ev_io_start (EV_A_ &w->io);
+
+ ev_prepare_init (&w->prepare, embed_prepare_cb);
+ ev_set_priority (&w->prepare, EV_MINPRI);
+ ev_prepare_start (EV_A_ &w->prepare);
+
+#if EV_FORK_ENABLE
+ ev_fork_init (&w->fork, embed_fork_cb);
+ ev_fork_start (EV_A_ &w->fork);
+#endif
+
+ /*ev_idle_init (&w->idle, e,bed_idle_cb);*/
+
+ ev_start (EV_A_ (W)w, 1);
+
+ EV_FREQUENT_CHECK;
+}
+
+void
+ev_embed_stop (EV_P_ ev_embed *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ ev_io_stop (EV_A_ &w->io);
+ ev_prepare_stop (EV_A_ &w->prepare);
+#if EV_FORK_ENABLE
+ ev_fork_stop (EV_A_ &w->fork);
+#endif
+
+ ev_stop (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+}
+#endif
+
+#if EV_FORK_ENABLE
+void
+ev_fork_start (EV_P_ ev_fork *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ ev_start (EV_A_ (W)w, ++forkcnt);
+ array_needsize (ev_fork *, forks, forkmax, forkcnt, array_needsize_noinit);
+ forks [forkcnt - 1] = w;
+
+ EV_FREQUENT_CHECK;
+}
+
+void
+ev_fork_stop (EV_P_ ev_fork *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ {
+ int active = ev_active (w);
+
+ forks [active - 1] = forks [--forkcnt];
+ ev_active (forks [active - 1]) = active;
+ }
+
+ ev_stop (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+}
+#endif
+
+#if EV_CLEANUP_ENABLE
+void
+ev_cleanup_start (EV_P_ ev_cleanup *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ ev_start (EV_A_ (W)w, ++cleanupcnt);
+ array_needsize (ev_cleanup *, cleanups, cleanupmax, cleanupcnt, array_needsize_noinit);
+ cleanups [cleanupcnt - 1] = w;
+
+ /* cleanup watchers should never keep a refcount on the loop */
+ ev_unref (EV_A);
+ EV_FREQUENT_CHECK;
+}
+
+void
+ev_cleanup_stop (EV_P_ ev_cleanup *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+ ev_ref (EV_A);
+
+ {
+ int active = ev_active (w);
+
+ cleanups [active - 1] = cleanups [--cleanupcnt];
+ ev_active (cleanups [active - 1]) = active;
+ }
+
+ ev_stop (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+}
+#endif
+
+#if EV_ASYNC_ENABLE
+void
+ev_async_start (EV_P_ ev_async *w) EV_NOEXCEPT
+{
+ if (ecb_expect_false (ev_is_active (w)))
+ return;
+
+ w->sent = 0;
+
+ evpipe_init (EV_A);
+
+ EV_FREQUENT_CHECK;
+
+ ev_start (EV_A_ (W)w, ++asynccnt);
+ array_needsize (ev_async *, asyncs, asyncmax, asynccnt, array_needsize_noinit);
+ asyncs [asynccnt - 1] = w;
+
+ EV_FREQUENT_CHECK;
+}
+
+void
+ev_async_stop (EV_P_ ev_async *w) EV_NOEXCEPT
+{
+ clear_pending (EV_A_ (W)w);
+ if (ecb_expect_false (!ev_is_active (w)))
+ return;
+
+ EV_FREQUENT_CHECK;
+
+ {
+ int active = ev_active (w);
+
+ asyncs [active - 1] = asyncs [--asynccnt];
+ ev_active (asyncs [active - 1]) = active;
+ }
+
+ ev_stop (EV_A_ (W)w);
+
+ EV_FREQUENT_CHECK;
+}
+
+void
+ev_async_send (EV_P_ ev_async *w) EV_NOEXCEPT
+{
+ w->sent = 1;
+ evpipe_write (EV_A_ &async_pending);
+}
+#endif
+
+/*****************************************************************************/
+
+struct ev_once
+{
+ ev_io io;
+ ev_timer to;
+ void (*cb)(int revents, void *arg);
+ void *arg;
+};
+
+static void
+once_cb (EV_P_ struct ev_once *once, int revents)
+{
+ void (*cb)(int revents, void *arg) = once->cb;
+ void *arg = once->arg;
+
+ ev_io_stop (EV_A_ &once->io);
+ ev_timer_stop (EV_A_ &once->to);
+ ev_free (once);
+
+ cb (revents, arg);
+}
+
+static void
+once_cb_io (EV_P_ ev_io *w, int revents)
+{
+ struct ev_once *once = (struct ev_once *)(((char *)w) - offsetof (struct ev_once, io));
+
+ once_cb (EV_A_ once, revents | ev_clear_pending (EV_A_ &once->to));
+}
+
+static void
+once_cb_to (EV_P_ ev_timer *w, int revents)
+{
+ struct ev_once *once = (struct ev_once *)(((char *)w) - offsetof (struct ev_once, to));
+
+ once_cb (EV_A_ once, revents | ev_clear_pending (EV_A_ &once->io));
+}
+
+void
+ev_once (EV_P_ int fd, int events, ev_tstamp timeout, void (*cb)(int revents, void *arg), void *arg) EV_NOEXCEPT
+{
+ struct ev_once *once = (struct ev_once *)ev_malloc (sizeof (struct ev_once));
+
+ once->cb = cb;
+ once->arg = arg;
+
+ ev_init (&once->io, once_cb_io);
+ if (fd >= 0)
+ {
+ ev_io_set (&once->io, fd, events);
+ ev_io_start (EV_A_ &once->io);
+ }
+
+ ev_init (&once->to, once_cb_to);
+ if (timeout >= 0.)
+ {
+ ev_timer_set (&once->to, timeout, 0.);
+ ev_timer_start (EV_A_ &once->to);
+ }
+}
+
+/*****************************************************************************/
+
+#if EV_WALK_ENABLE
+ecb_cold
+void
+ev_walk (EV_P_ int types, void (*cb)(EV_P_ int type, void *w)) EV_NOEXCEPT
+{
+ int i, j;
+ ev_watcher_list *wl, *wn;
+
+ if (types & (EV_IO | EV_EMBED))
+ for (i = 0; i < anfdmax; ++i)
+ for (wl = anfds [i].head; wl; )
+ {
+ wn = wl->next;
+
+#if EV_EMBED_ENABLE
+ if (ev_cb ((ev_io *)wl) == embed_io_cb)
+ {
+ if (types & EV_EMBED)
+ cb (EV_A_ EV_EMBED, ((char *)wl) - offsetof (struct ev_embed, io));
+ }
+ else
+#endif
+#if EV_USE_INOTIFY
+ if (ev_cb ((ev_io *)wl) == infy_cb)
+ ;
+ else
+#endif
+ if ((ev_io *)wl != &pipe_w)
+ if (types & EV_IO)
+ cb (EV_A_ EV_IO, wl);
+
+ wl = wn;
+ }
+
+ if (types & (EV_TIMER | EV_STAT))
+ for (i = timercnt + HEAP0; i-- > HEAP0; )
+#if EV_STAT_ENABLE
+ /*TODO: timer is not always active*/
+ if (ev_cb ((ev_timer *)ANHE_w (timers [i])) == stat_timer_cb)
+ {
+ if (types & EV_STAT)
+ cb (EV_A_ EV_STAT, ((char *)ANHE_w (timers [i])) - offsetof (struct ev_stat, timer));
+ }
+ else
+#endif
+ if (types & EV_TIMER)
+ cb (EV_A_ EV_TIMER, ANHE_w (timers [i]));
+
+#if EV_PERIODIC_ENABLE
+ if (types & EV_PERIODIC)
+ for (i = periodiccnt + HEAP0; i-- > HEAP0; )
+ cb (EV_A_ EV_PERIODIC, ANHE_w (periodics [i]));
+#endif
+
+#if EV_IDLE_ENABLE
+ if (types & EV_IDLE)
+ for (j = NUMPRI; j--; )
+ for (i = idlecnt [j]; i--; )
+ cb (EV_A_ EV_IDLE, idles [j][i]);
+#endif
+
+#if EV_FORK_ENABLE
+ if (types & EV_FORK)
+ for (i = forkcnt; i--; )
+ if (ev_cb (forks [i]) != embed_fork_cb)
+ cb (EV_A_ EV_FORK, forks [i]);
+#endif
+
+#if EV_ASYNC_ENABLE
+ if (types & EV_ASYNC)
+ for (i = asynccnt; i--; )
+ cb (EV_A_ EV_ASYNC, asyncs [i]);
+#endif
+
+#if EV_PREPARE_ENABLE
+ if (types & EV_PREPARE)
+ for (i = preparecnt; i--; )
+# if EV_EMBED_ENABLE
+ if (ev_cb (prepares [i]) != embed_prepare_cb)
+# endif
+ cb (EV_A_ EV_PREPARE, prepares [i]);
+#endif
+
+#if EV_CHECK_ENABLE
+ if (types & EV_CHECK)
+ for (i = checkcnt; i--; )
+ cb (EV_A_ EV_CHECK, checks [i]);
+#endif
+
+#if EV_SIGNAL_ENABLE
+ if (types & EV_SIGNAL)
+ for (i = 0; i < EV_NSIG - 1; ++i)
+ for (wl = signals [i].head; wl; )
+ {
+ wn = wl->next;
+ cb (EV_A_ EV_SIGNAL, wl);
+ wl = wn;
+ }
+#endif
+
+#if EV_CHILD_ENABLE
+ if (types & EV_CHILD)
+ for (i = (EV_PID_HASHSIZE); i--; )
+ for (wl = childs [i]; wl; )
+ {
+ wn = wl->next;
+ cb (EV_A_ EV_CHILD, wl);
+ wl = wn;
+ }
+#endif
+/* EV_STAT 0x00001000 /* stat data changed */
+/* EV_EMBED 0x00010000 /* embedded event loop needs sweep */
+}
+#endif
+
+#if EV_MULTIPLICITY
+ #include "ev_wrap.h"
+#endif
+
diff --git a/3rdparty/libev/ev.h b/3rdparty/libev/ev.h
new file mode 100644
index 0000000..4669c39
--- /dev/null
+++ b/3rdparty/libev/ev.h
@@ -0,0 +1,860 @@
+/*
+ * libev native API header
+ *
+ * Copyright (c) 2007-2020 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#ifndef EV_H_
+#define EV_H_
+
+#ifdef __cplusplus
+# define EV_CPP(x) x
+# if __cplusplus >= 201103L
+# define EV_NOEXCEPT noexcept
+# else
+# define EV_NOEXCEPT
+# endif
+#else
+# define EV_CPP(x)
+# define EV_NOEXCEPT
+#endif
+#define EV_THROW EV_NOEXCEPT /* pre-4.25, do not use in new code */
+
+EV_CPP(extern "C" {)
+
+/*****************************************************************************/
+
+/* pre-4.0 compatibility */
+#ifndef EV_COMPAT3
+# define EV_COMPAT3 1
+#endif
+
+#ifndef EV_FEATURES
+# if defined __OPTIMIZE_SIZE__
+# define EV_FEATURES 0x7c
+# else
+# define EV_FEATURES 0x7f
+# endif
+#endif
+
+#define EV_FEATURE_CODE ((EV_FEATURES) & 1)
+#define EV_FEATURE_DATA ((EV_FEATURES) & 2)
+#define EV_FEATURE_CONFIG ((EV_FEATURES) & 4)
+#define EV_FEATURE_API ((EV_FEATURES) & 8)
+#define EV_FEATURE_WATCHERS ((EV_FEATURES) & 16)
+#define EV_FEATURE_BACKENDS ((EV_FEATURES) & 32)
+#define EV_FEATURE_OS ((EV_FEATURES) & 64)
+
+/* these priorities are inclusive, higher priorities will be invoked earlier */
+#ifndef EV_MINPRI
+# define EV_MINPRI (EV_FEATURE_CONFIG ? -2 : 0)
+#endif
+#ifndef EV_MAXPRI
+# define EV_MAXPRI (EV_FEATURE_CONFIG ? +2 : 0)
+#endif
+
+#ifndef EV_MULTIPLICITY
+# define EV_MULTIPLICITY EV_FEATURE_CONFIG
+#endif
+
+#ifndef EV_PERIODIC_ENABLE
+# define EV_PERIODIC_ENABLE EV_FEATURE_WATCHERS
+#endif
+
+#ifndef EV_STAT_ENABLE
+# define EV_STAT_ENABLE EV_FEATURE_WATCHERS
+#endif
+
+#ifndef EV_PREPARE_ENABLE
+# define EV_PREPARE_ENABLE EV_FEATURE_WATCHERS
+#endif
+
+#ifndef EV_CHECK_ENABLE
+# define EV_CHECK_ENABLE EV_FEATURE_WATCHERS
+#endif
+
+#ifndef EV_IDLE_ENABLE
+# define EV_IDLE_ENABLE EV_FEATURE_WATCHERS
+#endif
+
+#ifndef EV_FORK_ENABLE
+# define EV_FORK_ENABLE EV_FEATURE_WATCHERS
+#endif
+
+#ifndef EV_CLEANUP_ENABLE
+# define EV_CLEANUP_ENABLE EV_FEATURE_WATCHERS
+#endif
+
+#ifndef EV_SIGNAL_ENABLE
+# define EV_SIGNAL_ENABLE EV_FEATURE_WATCHERS
+#endif
+
+#ifndef EV_CHILD_ENABLE
+# ifdef _WIN32
+# define EV_CHILD_ENABLE 0
+# else
+# define EV_CHILD_ENABLE EV_FEATURE_WATCHERS
+#endif
+#endif
+
+#ifndef EV_ASYNC_ENABLE
+# define EV_ASYNC_ENABLE EV_FEATURE_WATCHERS
+#endif
+
+#ifndef EV_EMBED_ENABLE
+# define EV_EMBED_ENABLE EV_FEATURE_WATCHERS
+#endif
+
+#ifndef EV_WALK_ENABLE
+# define EV_WALK_ENABLE 0 /* not yet */
+#endif
+
+/*****************************************************************************/
+
+#if EV_CHILD_ENABLE && !EV_SIGNAL_ENABLE
+# undef EV_SIGNAL_ENABLE
+# define EV_SIGNAL_ENABLE 1
+#endif
+
+/*****************************************************************************/
+
+#ifndef EV_TSTAMP_T
+# define EV_TSTAMP_T double
+#endif
+typedef EV_TSTAMP_T ev_tstamp;
+
+#include <string.h> /* for memmove */
+
+#ifndef EV_ATOMIC_T
+# include <signal.h>
+# define EV_ATOMIC_T sig_atomic_t volatile
+#endif
+
+#if EV_STAT_ENABLE
+# ifdef _WIN32
+# include <time.h>
+# include <sys/types.h>
+# endif
+# include <sys/stat.h>
+#endif
+
+/* support multiple event loops? */
+#if EV_MULTIPLICITY
+struct ev_loop;
+# define EV_P struct ev_loop *loop /* a loop as sole parameter in a declaration */
+# define EV_P_ EV_P, /* a loop as first of multiple parameters */
+# define EV_A loop /* a loop as sole argument to a function call */
+# define EV_A_ EV_A, /* a loop as first of multiple arguments */
+# define EV_DEFAULT_UC ev_default_loop_uc_ () /* the default loop, if initialised, as sole arg */
+# define EV_DEFAULT_UC_ EV_DEFAULT_UC, /* the default loop as first of multiple arguments */
+# define EV_DEFAULT ev_default_loop (0) /* the default loop as sole arg */
+# define EV_DEFAULT_ EV_DEFAULT, /* the default loop as first of multiple arguments */
+#else
+# define EV_P void
+# define EV_P_
+# define EV_A
+# define EV_A_
+# define EV_DEFAULT
+# define EV_DEFAULT_
+# define EV_DEFAULT_UC
+# define EV_DEFAULT_UC_
+# undef EV_EMBED_ENABLE
+#endif
+
+/* EV_INLINE is used for functions in header files */
+#if __STDC_VERSION__ >= 199901L || __GNUC__ >= 3
+# define EV_INLINE static inline
+#else
+# define EV_INLINE static
+#endif
+
+#ifdef EV_API_STATIC
+# define EV_API_DECL static
+#else
+# define EV_API_DECL extern
+#endif
+
+/* EV_PROTOTYPES can be used to switch of prototype declarations */
+#ifndef EV_PROTOTYPES
+# define EV_PROTOTYPES 1
+#endif
+
+/*****************************************************************************/
+
+#define EV_VERSION_MAJOR 4
+#define EV_VERSION_MINOR 33
+
+/* eventmask, revents, events... */
+enum {
+ EV_UNDEF = (int)0xFFFFFFFF, /* guaranteed to be invalid */
+ EV_NONE = 0x00, /* no events */
+ EV_READ = 0x01, /* ev_io detected read will not block */
+ EV_WRITE = 0x02, /* ev_io detected write will not block */
+ EV__IOFDSET = 0x80, /* internal use only */
+ EV_IO = EV_READ, /* alias for type-detection */
+ EV_TIMER = 0x00000100, /* timer timed out */
+#if EV_COMPAT3
+ EV_TIMEOUT = EV_TIMER, /* pre 4.0 API compatibility */
+#endif
+ EV_PERIODIC = 0x00000200, /* periodic timer timed out */
+ EV_SIGNAL = 0x00000400, /* signal was received */
+ EV_CHILD = 0x00000800, /* child/pid had status change */
+ EV_STAT = 0x00001000, /* stat data changed */
+ EV_IDLE = 0x00002000, /* event loop is idling */
+ EV_PREPARE = 0x00004000, /* event loop about to poll */
+ EV_CHECK = 0x00008000, /* event loop finished poll */
+ EV_EMBED = 0x00010000, /* embedded event loop needs sweep */
+ EV_FORK = 0x00020000, /* event loop resumed in child */
+ EV_CLEANUP = 0x00040000, /* event loop resumed in child */
+ EV_ASYNC = 0x00080000, /* async intra-loop signal */
+ EV_CUSTOM = 0x01000000, /* for use by user code */
+ EV_ERROR = (int)0x80000000 /* sent when an error occurs */
+};
+
+/* can be used to add custom fields to all watchers, while losing binary compatibility */
+#ifndef EV_COMMON
+# define EV_COMMON void *data;
+#endif
+
+#ifndef EV_CB_DECLARE
+# define EV_CB_DECLARE(type) void (*cb)(EV_P_ struct type *w, int revents);
+#endif
+#ifndef EV_CB_INVOKE
+# define EV_CB_INVOKE(watcher,revents) (watcher)->cb (EV_A_ (watcher), (revents))
+#endif
+
+/* not official, do not use */
+#define EV_CB(type,name) void name (EV_P_ struct ev_ ## type *w, int revents)
+
+/*
+ * struct member types:
+ * private: you may look at them, but not change them,
+ * and they might not mean anything to you.
+ * ro: can be read anytime, but only changed when the watcher isn't active.
+ * rw: can be read and modified anytime, even when the watcher is active.
+ *
+ * some internal details that might be helpful for debugging:
+ *
+ * active is either 0, which means the watcher is not active,
+ * or the array index of the watcher (periodics, timers)
+ * or the array index + 1 (most other watchers)
+ * or simply 1 for watchers that aren't in some array.
+ * pending is either 0, in which case the watcher isn't,
+ * or the array index + 1 in the pendings array.
+ */
+
+#if EV_MINPRI == EV_MAXPRI
+# define EV_DECL_PRIORITY
+#elif !defined (EV_DECL_PRIORITY)
+# define EV_DECL_PRIORITY int priority;
+#endif
+
+/* shared by all watchers */
+#define EV_WATCHER(type) \
+ int active; /* private */ \
+ int pending; /* private */ \
+ EV_DECL_PRIORITY /* private */ \
+ EV_COMMON /* rw */ \
+ EV_CB_DECLARE (type) /* private */
+
+#define EV_WATCHER_LIST(type) \
+ EV_WATCHER (type) \
+ struct ev_watcher_list *next; /* private */
+
+#define EV_WATCHER_TIME(type) \
+ EV_WATCHER (type) \
+ ev_tstamp at; /* private */
+
+/* base class, nothing to see here unless you subclass */
+typedef struct ev_watcher
+{
+ EV_WATCHER (ev_watcher)
+} ev_watcher;
+
+/* base class, nothing to see here unless you subclass */
+typedef struct ev_watcher_list
+{
+ EV_WATCHER_LIST (ev_watcher_list)
+} ev_watcher_list;
+
+/* base class, nothing to see here unless you subclass */
+typedef struct ev_watcher_time
+{
+ EV_WATCHER_TIME (ev_watcher_time)
+} ev_watcher_time;
+
+/* invoked when fd is either EV_READable or EV_WRITEable */
+/* revent EV_READ, EV_WRITE */
+typedef struct ev_io
+{
+ EV_WATCHER_LIST (ev_io)
+
+ int fd; /* ro */
+ int events; /* ro */
+} ev_io;
+
+/* invoked after a specific time, repeatable (based on monotonic clock) */
+/* revent EV_TIMEOUT */
+typedef struct ev_timer
+{
+ EV_WATCHER_TIME (ev_timer)
+
+ ev_tstamp repeat; /* rw */
+} ev_timer;
+
+/* invoked at some specific time, possibly repeating at regular intervals (based on UTC) */
+/* revent EV_PERIODIC */
+typedef struct ev_periodic
+{
+ EV_WATCHER_TIME (ev_periodic)
+
+ ev_tstamp offset; /* rw */
+ ev_tstamp interval; /* rw */
+ ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) EV_NOEXCEPT; /* rw */
+} ev_periodic;
+
+/* invoked when the given signal has been received */
+/* revent EV_SIGNAL */
+typedef struct ev_signal
+{
+ EV_WATCHER_LIST (ev_signal)
+
+ int signum; /* ro */
+} ev_signal;
+
+/* invoked when sigchld is received and waitpid indicates the given pid */
+/* revent EV_CHILD */
+/* does not support priorities */
+typedef struct ev_child
+{
+ EV_WATCHER_LIST (ev_child)
+
+ int flags; /* private */
+ int pid; /* ro */
+ int rpid; /* rw, holds the received pid */
+ int rstatus; /* rw, holds the exit status, use the macros from sys/wait.h */
+} ev_child;
+
+#if EV_STAT_ENABLE
+/* st_nlink = 0 means missing file or other error */
+# ifdef _WIN32
+typedef struct _stati64 ev_statdata;
+# else
+typedef struct stat ev_statdata;
+# endif
+
+/* invoked each time the stat data changes for a given path */
+/* revent EV_STAT */
+typedef struct ev_stat
+{
+ EV_WATCHER_LIST (ev_stat)
+
+ ev_timer timer; /* private */
+ ev_tstamp interval; /* ro */
+ const char *path; /* ro */
+ ev_statdata prev; /* ro */
+ ev_statdata attr; /* ro */
+
+ int wd; /* wd for inotify, fd for kqueue */
+} ev_stat;
+#endif
+
+/* invoked when the nothing else needs to be done, keeps the process from blocking */
+/* revent EV_IDLE */
+typedef struct ev_idle
+{
+ EV_WATCHER (ev_idle)
+} ev_idle;
+
+/* invoked for each run of the mainloop, just before the blocking call */
+/* you can still change events in any way you like */
+/* revent EV_PREPARE */
+typedef struct ev_prepare
+{
+ EV_WATCHER (ev_prepare)
+} ev_prepare;
+
+/* invoked for each run of the mainloop, just after the blocking call */
+/* revent EV_CHECK */
+typedef struct ev_check
+{
+ EV_WATCHER (ev_check)
+} ev_check;
+
+/* the callback gets invoked before check in the child process when a fork was detected */
+/* revent EV_FORK */
+typedef struct ev_fork
+{
+ EV_WATCHER (ev_fork)
+} ev_fork;
+
+/* is invoked just before the loop gets destroyed */
+/* revent EV_CLEANUP */
+typedef struct ev_cleanup
+{
+ EV_WATCHER (ev_cleanup)
+} ev_cleanup;
+
+#if EV_EMBED_ENABLE
+/* used to embed an event loop inside another */
+/* the callback gets invoked when the event loop has handled events, and can be 0 */
+typedef struct ev_embed
+{
+ EV_WATCHER (ev_embed)
+
+ struct ev_loop *other; /* ro */
+#undef EV_IO_ENABLE
+#define EV_IO_ENABLE 1
+ ev_io io; /* private */
+#undef EV_PREPARE_ENABLE
+#define EV_PREPARE_ENABLE 1
+ ev_prepare prepare; /* private */
+ ev_check check; /* unused */
+ ev_timer timer; /* unused */
+ ev_periodic periodic; /* unused */
+ ev_idle idle; /* unused */
+ ev_fork fork; /* private */
+ ev_cleanup cleanup; /* unused */
+} ev_embed;
+#endif
+
+#if EV_ASYNC_ENABLE
+/* invoked when somebody calls ev_async_send on the watcher */
+/* revent EV_ASYNC */
+typedef struct ev_async
+{
+ EV_WATCHER (ev_async)
+
+ EV_ATOMIC_T sent; /* private */
+} ev_async;
+
+# define ev_async_pending(w) (+(w)->sent)
+#endif
+
+/* the presence of this union forces similar struct layout */
+union ev_any_watcher
+{
+ struct ev_watcher w;
+ struct ev_watcher_list wl;
+
+ struct ev_io io;
+ struct ev_timer timer;
+ struct ev_periodic periodic;
+ struct ev_signal signal;
+ struct ev_child child;
+#if EV_STAT_ENABLE
+ struct ev_stat stat;
+#endif
+#if EV_IDLE_ENABLE
+ struct ev_idle idle;
+#endif
+ struct ev_prepare prepare;
+ struct ev_check check;
+#if EV_FORK_ENABLE
+ struct ev_fork fork;
+#endif
+#if EV_CLEANUP_ENABLE
+ struct ev_cleanup cleanup;
+#endif
+#if EV_EMBED_ENABLE
+ struct ev_embed embed;
+#endif
+#if EV_ASYNC_ENABLE
+ struct ev_async async;
+#endif
+};
+
+/* flag bits for ev_default_loop and ev_loop_new */
+enum {
+ /* the default */
+ EVFLAG_AUTO = 0x00000000U, /* not quite a mask */
+ /* flag bits */
+ EVFLAG_NOENV = 0x01000000U, /* do NOT consult environment */
+ EVFLAG_FORKCHECK = 0x02000000U, /* check for a fork in each iteration */
+ /* debugging/feature disable */
+ EVFLAG_NOINOTIFY = 0x00100000U, /* do not attempt to use inotify */
+#if EV_COMPAT3
+ EVFLAG_NOSIGFD = 0, /* compatibility to pre-3.9 */
+#endif
+ EVFLAG_SIGNALFD = 0x00200000U, /* attempt to use signalfd */
+ EVFLAG_NOSIGMASK = 0x00400000U, /* avoid modifying the signal mask */
+ EVFLAG_NOTIMERFD = 0x00800000U /* avoid creating a timerfd */
+};
+
+/* method bits to be ored together */
+enum {
+ EVBACKEND_SELECT = 0x00000001U, /* available just about anywhere */
+ EVBACKEND_POLL = 0x00000002U, /* !win, !aix, broken on osx */
+ EVBACKEND_EPOLL = 0x00000004U, /* linux */
+ EVBACKEND_KQUEUE = 0x00000008U, /* bsd, broken on osx */
+ EVBACKEND_DEVPOLL = 0x00000010U, /* solaris 8 */ /* NYI */
+ EVBACKEND_PORT = 0x00000020U, /* solaris 10 */
+ EVBACKEND_LINUXAIO = 0x00000040U, /* linux AIO, 4.19+ */
+ EVBACKEND_IOURING = 0x00000080U, /* linux io_uring, 5.1+ */
+ EVBACKEND_ALL = 0x000000FFU, /* all known backends */
+ EVBACKEND_MASK = 0x0000FFFFU /* all future backends */
+};
+
+#if EV_PROTOTYPES
+EV_API_DECL int ev_version_major (void) EV_NOEXCEPT;
+EV_API_DECL int ev_version_minor (void) EV_NOEXCEPT;
+
+EV_API_DECL unsigned int ev_supported_backends (void) EV_NOEXCEPT;
+EV_API_DECL unsigned int ev_recommended_backends (void) EV_NOEXCEPT;
+EV_API_DECL unsigned int ev_embeddable_backends (void) EV_NOEXCEPT;
+
+EV_API_DECL ev_tstamp ev_time (void) EV_NOEXCEPT;
+EV_API_DECL void ev_sleep (ev_tstamp delay) EV_NOEXCEPT; /* sleep for a while */
+
+/* Sets the allocation function to use, works like realloc.
+ * It is used to allocate and free memory.
+ * If it returns zero when memory needs to be allocated, the library might abort
+ * or take some potentially destructive action.
+ * The default is your system realloc function.
+ */
+EV_API_DECL void ev_set_allocator (void *(*cb)(void *ptr, long size) EV_NOEXCEPT) EV_NOEXCEPT;
+
+/* set the callback function to call on a
+ * retryable syscall error
+ * (such as failed select, poll, epoll_wait)
+ */
+EV_API_DECL void ev_set_syserr_cb (void (*cb)(const char *msg) EV_NOEXCEPT) EV_NOEXCEPT;
+
+#if EV_MULTIPLICITY
+
+/* the default loop is the only one that handles signals and child watchers */
+/* you can call this as often as you like */
+EV_API_DECL struct ev_loop *ev_default_loop (unsigned int flags EV_CPP (= 0)) EV_NOEXCEPT;
+
+#ifdef EV_API_STATIC
+EV_API_DECL struct ev_loop *ev_default_loop_ptr;
+#endif
+
+EV_INLINE struct ev_loop *
+ev_default_loop_uc_ (void) EV_NOEXCEPT
+{
+ extern struct ev_loop *ev_default_loop_ptr;
+
+ return ev_default_loop_ptr;
+}
+
+EV_INLINE int
+ev_is_default_loop (EV_P) EV_NOEXCEPT
+{
+ return EV_A == EV_DEFAULT_UC;
+}
+
+/* create and destroy alternative loops that don't handle signals */
+EV_API_DECL struct ev_loop *ev_loop_new (unsigned int flags EV_CPP (= 0)) EV_NOEXCEPT;
+
+EV_API_DECL ev_tstamp ev_now (EV_P) EV_NOEXCEPT; /* time w.r.t. timers and the eventloop, updated after each poll */
+
+#else
+
+EV_API_DECL int ev_default_loop (unsigned int flags EV_CPP (= 0)) EV_NOEXCEPT; /* returns true when successful */
+
+EV_API_DECL ev_tstamp ev_rt_now;
+
+EV_INLINE ev_tstamp
+ev_now (void) EV_NOEXCEPT
+{
+ return ev_rt_now;
+}
+
+/* looks weird, but ev_is_default_loop (EV_A) still works if this exists */
+EV_INLINE int
+ev_is_default_loop (void) EV_NOEXCEPT
+{
+ return 1;
+}
+
+#endif /* multiplicity */
+
+/* destroy event loops, also works for the default loop */
+EV_API_DECL void ev_loop_destroy (EV_P);
+
+/* this needs to be called after fork, to duplicate the loop */
+/* when you want to re-use it in the child */
+/* you can call it in either the parent or the child */
+/* you can actually call it at any time, anywhere :) */
+EV_API_DECL void ev_loop_fork (EV_P) EV_NOEXCEPT;
+
+EV_API_DECL unsigned int ev_backend (EV_P) EV_NOEXCEPT; /* backend in use by loop */
+
+EV_API_DECL void ev_now_update (EV_P) EV_NOEXCEPT; /* update event loop time */
+
+#if EV_WALK_ENABLE
+/* walk (almost) all watchers in the loop of a given type, invoking the */
+/* callback on every such watcher. The callback might stop the watcher, */
+/* but do nothing else with the loop */
+EV_API_DECL void ev_walk (EV_P_ int types, void (*cb)(EV_P_ int type, void *w)) EV_NOEXCEPT;
+#endif
+
+#endif /* prototypes */
+
+/* ev_run flags values */
+enum {
+ EVRUN_NOWAIT = 1, /* do not block/wait */
+ EVRUN_ONCE = 2 /* block *once* only */
+};
+
+/* ev_break how values */
+enum {
+ EVBREAK_CANCEL = 0, /* undo unloop */
+ EVBREAK_ONE = 1, /* unloop once */
+ EVBREAK_ALL = 2 /* unloop all loops */
+};
+
+#if EV_PROTOTYPES
+EV_API_DECL int ev_run (EV_P_ int flags EV_CPP (= 0));
+EV_API_DECL void ev_break (EV_P_ int how EV_CPP (= EVBREAK_ONE)) EV_NOEXCEPT; /* break out of the loop */
+
+/*
+ * ref/unref can be used to add or remove a refcount on the mainloop. every watcher
+ * keeps one reference. if you have a long-running watcher you never unregister that
+ * should not keep ev_loop from running, unref() after starting, and ref() before stopping.
+ */
+EV_API_DECL void ev_ref (EV_P) EV_NOEXCEPT;
+EV_API_DECL void ev_unref (EV_P) EV_NOEXCEPT;
+
+/*
+ * convenience function, wait for a single event, without registering an event watcher
+ * if timeout is < 0, do wait indefinitely
+ */
+EV_API_DECL void ev_once (EV_P_ int fd, int events, ev_tstamp timeout, void (*cb)(int revents, void *arg), void *arg) EV_NOEXCEPT;
+
+EV_API_DECL void ev_invoke_pending (EV_P); /* invoke all pending watchers */
+
+# if EV_FEATURE_API
+EV_API_DECL unsigned int ev_iteration (EV_P) EV_NOEXCEPT; /* number of loop iterations */
+EV_API_DECL unsigned int ev_depth (EV_P) EV_NOEXCEPT; /* #ev_loop enters - #ev_loop leaves */
+EV_API_DECL void ev_verify (EV_P) EV_NOEXCEPT; /* abort if loop data corrupted */
+
+EV_API_DECL void ev_set_io_collect_interval (EV_P_ ev_tstamp interval) EV_NOEXCEPT; /* sleep at least this time, default 0 */
+EV_API_DECL void ev_set_timeout_collect_interval (EV_P_ ev_tstamp interval) EV_NOEXCEPT; /* sleep at least this time, default 0 */
+
+/* advanced stuff for threading etc. support, see docs */
+EV_API_DECL void ev_set_userdata (EV_P_ void *data) EV_NOEXCEPT;
+EV_API_DECL void *ev_userdata (EV_P) EV_NOEXCEPT;
+typedef void (*ev_loop_callback)(EV_P);
+EV_API_DECL void ev_set_invoke_pending_cb (EV_P_ ev_loop_callback invoke_pending_cb) EV_NOEXCEPT;
+/* C++ doesn't allow the use of the ev_loop_callback typedef here, so we need to spell it out */
+EV_API_DECL void ev_set_loop_release_cb (EV_P_ void (*release)(EV_P) EV_NOEXCEPT, void (*acquire)(EV_P) EV_NOEXCEPT) EV_NOEXCEPT;
+
+EV_API_DECL unsigned int ev_pending_count (EV_P) EV_NOEXCEPT; /* number of pending events, if any */
+
+/*
+ * stop/start the timer handling.
+ */
+EV_API_DECL void ev_suspend (EV_P) EV_NOEXCEPT;
+EV_API_DECL void ev_resume (EV_P) EV_NOEXCEPT;
+#endif
+
+#endif
+
+/* these may evaluate ev multiple times, and the other arguments at most once */
+/* either use ev_init + ev_TYPE_set, or the ev_TYPE_init macro, below, to first initialise a watcher */
+#define ev_init(ev,cb_) do { \
+ ((ev_watcher *)(void *)(ev))->active = \
+ ((ev_watcher *)(void *)(ev))->pending = 0; \
+ ev_set_priority ((ev), 0); \
+ ev_set_cb ((ev), cb_); \
+} while (0)
+
+#define ev_io_modify(ev,events_) do { (ev)->events = (ev)->events & EV__IOFDSET | (events_); } while (0)
+#define ev_io_set(ev,fd_,events_) do { (ev)->fd = (fd_); (ev)->events = (events_) | EV__IOFDSET; } while (0)
+#define ev_timer_set(ev,after_,repeat_) do { ((ev_watcher_time *)(ev))->at = (after_); (ev)->repeat = (repeat_); } while (0)
+#define ev_periodic_set(ev,ofs_,ival_,rcb_) do { (ev)->offset = (ofs_); (ev)->interval = (ival_); (ev)->reschedule_cb = (rcb_); } while (0)
+#define ev_signal_set(ev,signum_) do { (ev)->signum = (signum_); } while (0)
+#define ev_child_set(ev,pid_,trace_) do { (ev)->pid = (pid_); (ev)->flags = !!(trace_); } while (0)
+#define ev_stat_set(ev,path_,interval_) do { (ev)->path = (path_); (ev)->interval = (interval_); (ev)->wd = -2; } while (0)
+#define ev_idle_set(ev) /* nop, yes, this is a serious in-joke */
+#define ev_prepare_set(ev) /* nop, yes, this is a serious in-joke */
+#define ev_check_set(ev) /* nop, yes, this is a serious in-joke */
+#define ev_embed_set(ev,other_) do { (ev)->other = (other_); } while (0)
+#define ev_fork_set(ev) /* nop, yes, this is a serious in-joke */
+#define ev_cleanup_set(ev) /* nop, yes, this is a serious in-joke */
+#define ev_async_set(ev) /* nop, yes, this is a serious in-joke */
+
+#define ev_io_init(ev,cb,fd,events) do { ev_init ((ev), (cb)); ev_io_set ((ev),(fd),(events)); } while (0)
+#define ev_timer_init(ev,cb,after,repeat) do { ev_init ((ev), (cb)); ev_timer_set ((ev),(after),(repeat)); } while (0)
+#define ev_periodic_init(ev,cb,ofs,ival,rcb) do { ev_init ((ev), (cb)); ev_periodic_set ((ev),(ofs),(ival),(rcb)); } while (0)
+#define ev_signal_init(ev,cb,signum) do { ev_init ((ev), (cb)); ev_signal_set ((ev), (signum)); } while (0)
+#define ev_child_init(ev,cb,pid,trace) do { ev_init ((ev), (cb)); ev_child_set ((ev),(pid),(trace)); } while (0)
+#define ev_stat_init(ev,cb,path,interval) do { ev_init ((ev), (cb)); ev_stat_set ((ev),(path),(interval)); } while (0)
+#define ev_idle_init(ev,cb) do { ev_init ((ev), (cb)); ev_idle_set ((ev)); } while (0)
+#define ev_prepare_init(ev,cb) do { ev_init ((ev), (cb)); ev_prepare_set ((ev)); } while (0)
+#define ev_check_init(ev,cb) do { ev_init ((ev), (cb)); ev_check_set ((ev)); } while (0)
+#define ev_embed_init(ev,cb,other) do { ev_init ((ev), (cb)); ev_embed_set ((ev),(other)); } while (0)
+#define ev_fork_init(ev,cb) do { ev_init ((ev), (cb)); ev_fork_set ((ev)); } while (0)
+#define ev_cleanup_init(ev,cb) do { ev_init ((ev), (cb)); ev_cleanup_set ((ev)); } while (0)
+#define ev_async_init(ev,cb) do { ev_init ((ev), (cb)); ev_async_set ((ev)); } while (0)
+
+#define ev_is_pending(ev) (0 + ((ev_watcher *)(void *)(ev))->pending) /* ro, true when watcher is waiting for callback invocation */
+#define ev_is_active(ev) (0 + ((ev_watcher *)(void *)(ev))->active) /* ro, true when the watcher has been started */
+
+#define ev_cb_(ev) (ev)->cb /* rw */
+#define ev_cb(ev) (memmove (&ev_cb_ (ev), &((ev_watcher *)(ev))->cb, sizeof (ev_cb_ (ev))), (ev)->cb)
+
+#if EV_MINPRI == EV_MAXPRI
+# define ev_priority(ev) ((ev), EV_MINPRI)
+# define ev_set_priority(ev,pri) ((ev), (pri))
+#else
+# define ev_priority(ev) (+(((ev_watcher *)(void *)(ev))->priority))
+# define ev_set_priority(ev,pri) ( (ev_watcher *)(void *)(ev))->priority = (pri)
+#endif
+
+#define ev_periodic_at(ev) (+((ev_watcher_time *)(ev))->at)
+
+#ifndef ev_set_cb
+/* memmove is used here to avoid strict aliasing violations, and hopefully is optimized out by any reasonable compiler */
+# define ev_set_cb(ev,cb_) (ev_cb_ (ev) = (cb_), memmove (&((ev_watcher *)(ev))->cb, &ev_cb_ (ev), sizeof (ev_cb_ (ev))))
+#endif
+
+/* stopping (enabling, adding) a watcher does nothing if it is already running */
+/* stopping (disabling, deleting) a watcher does nothing unless it's already running */
+#if EV_PROTOTYPES
+
+/* feeds an event into a watcher as if the event actually occurred */
+/* accepts any ev_watcher type */
+EV_API_DECL void ev_feed_event (EV_P_ void *w, int revents) EV_NOEXCEPT;
+EV_API_DECL void ev_feed_fd_event (EV_P_ int fd, int revents) EV_NOEXCEPT;
+#if EV_SIGNAL_ENABLE
+EV_API_DECL void ev_feed_signal (int signum) EV_NOEXCEPT;
+EV_API_DECL void ev_feed_signal_event (EV_P_ int signum) EV_NOEXCEPT;
+#endif
+EV_API_DECL void ev_invoke (EV_P_ void *w, int revents);
+EV_API_DECL int ev_clear_pending (EV_P_ void *w) EV_NOEXCEPT;
+
+EV_API_DECL void ev_io_start (EV_P_ ev_io *w) EV_NOEXCEPT;
+EV_API_DECL void ev_io_stop (EV_P_ ev_io *w) EV_NOEXCEPT;
+
+EV_API_DECL void ev_timer_start (EV_P_ ev_timer *w) EV_NOEXCEPT;
+EV_API_DECL void ev_timer_stop (EV_P_ ev_timer *w) EV_NOEXCEPT;
+/* stops if active and no repeat, restarts if active and repeating, starts if inactive and repeating */
+EV_API_DECL void ev_timer_again (EV_P_ ev_timer *w) EV_NOEXCEPT;
+/* return remaining time */
+EV_API_DECL ev_tstamp ev_timer_remaining (EV_P_ ev_timer *w) EV_NOEXCEPT;
+
+#if EV_PERIODIC_ENABLE
+EV_API_DECL void ev_periodic_start (EV_P_ ev_periodic *w) EV_NOEXCEPT;
+EV_API_DECL void ev_periodic_stop (EV_P_ ev_periodic *w) EV_NOEXCEPT;
+EV_API_DECL void ev_periodic_again (EV_P_ ev_periodic *w) EV_NOEXCEPT;
+#endif
+
+/* only supported in the default loop */
+#if EV_SIGNAL_ENABLE
+EV_API_DECL void ev_signal_start (EV_P_ ev_signal *w) EV_NOEXCEPT;
+EV_API_DECL void ev_signal_stop (EV_P_ ev_signal *w) EV_NOEXCEPT;
+#endif
+
+/* only supported in the default loop */
+# if EV_CHILD_ENABLE
+EV_API_DECL void ev_child_start (EV_P_ ev_child *w) EV_NOEXCEPT;
+EV_API_DECL void ev_child_stop (EV_P_ ev_child *w) EV_NOEXCEPT;
+# endif
+
+# if EV_STAT_ENABLE
+EV_API_DECL void ev_stat_start (EV_P_ ev_stat *w) EV_NOEXCEPT;
+EV_API_DECL void ev_stat_stop (EV_P_ ev_stat *w) EV_NOEXCEPT;
+EV_API_DECL void ev_stat_stat (EV_P_ ev_stat *w) EV_NOEXCEPT;
+# endif
+
+# if EV_IDLE_ENABLE
+EV_API_DECL void ev_idle_start (EV_P_ ev_idle *w) EV_NOEXCEPT;
+EV_API_DECL void ev_idle_stop (EV_P_ ev_idle *w) EV_NOEXCEPT;
+# endif
+
+#if EV_PREPARE_ENABLE
+EV_API_DECL void ev_prepare_start (EV_P_ ev_prepare *w) EV_NOEXCEPT;
+EV_API_DECL void ev_prepare_stop (EV_P_ ev_prepare *w) EV_NOEXCEPT;
+#endif
+
+#if EV_CHECK_ENABLE
+EV_API_DECL void ev_check_start (EV_P_ ev_check *w) EV_NOEXCEPT;
+EV_API_DECL void ev_check_stop (EV_P_ ev_check *w) EV_NOEXCEPT;
+#endif
+
+# if EV_FORK_ENABLE
+EV_API_DECL void ev_fork_start (EV_P_ ev_fork *w) EV_NOEXCEPT;
+EV_API_DECL void ev_fork_stop (EV_P_ ev_fork *w) EV_NOEXCEPT;
+# endif
+
+# if EV_CLEANUP_ENABLE
+EV_API_DECL void ev_cleanup_start (EV_P_ ev_cleanup *w) EV_NOEXCEPT;
+EV_API_DECL void ev_cleanup_stop (EV_P_ ev_cleanup *w) EV_NOEXCEPT;
+# endif
+
+# if EV_EMBED_ENABLE
+/* only supported when loop to be embedded is in fact embeddable */
+EV_API_DECL void ev_embed_start (EV_P_ ev_embed *w) EV_NOEXCEPT;
+EV_API_DECL void ev_embed_stop (EV_P_ ev_embed *w) EV_NOEXCEPT;
+EV_API_DECL void ev_embed_sweep (EV_P_ ev_embed *w) EV_NOEXCEPT;
+# endif
+
+# if EV_ASYNC_ENABLE
+EV_API_DECL void ev_async_start (EV_P_ ev_async *w) EV_NOEXCEPT;
+EV_API_DECL void ev_async_stop (EV_P_ ev_async *w) EV_NOEXCEPT;
+EV_API_DECL void ev_async_send (EV_P_ ev_async *w) EV_NOEXCEPT;
+# endif
+
+#if EV_COMPAT3
+ #define EVLOOP_NONBLOCK EVRUN_NOWAIT
+ #define EVLOOP_ONESHOT EVRUN_ONCE
+ #define EVUNLOOP_CANCEL EVBREAK_CANCEL
+ #define EVUNLOOP_ONE EVBREAK_ONE
+ #define EVUNLOOP_ALL EVBREAK_ALL
+ #if EV_PROTOTYPES
+ EV_INLINE void ev_loop (EV_P_ int flags) { ev_run (EV_A_ flags); }
+ EV_INLINE void ev_unloop (EV_P_ int how ) { ev_break (EV_A_ how ); }
+ EV_INLINE void ev_default_destroy (void) { ev_loop_destroy (EV_DEFAULT); }
+ EV_INLINE void ev_default_fork (void) { ev_loop_fork (EV_DEFAULT); }
+ #if EV_FEATURE_API
+ EV_INLINE unsigned int ev_loop_count (EV_P) { return ev_iteration (EV_A); }
+ EV_INLINE unsigned int ev_loop_depth (EV_P) { return ev_depth (EV_A); }
+ EV_INLINE void ev_loop_verify (EV_P) { ev_verify (EV_A); }
+ #endif
+ #endif
+#else
+ typedef struct ev_loop ev_loop;
+#endif
+
+#endif
+
+EV_CPP(})
+
+#endif
+
diff --git a/3rdparty/libev/ev.pod b/3rdparty/libev/ev.pod
new file mode 100644
index 0000000..e4eeb50
--- /dev/null
+++ b/3rdparty/libev/ev.pod
@@ -0,0 +1,5741 @@
+=encoding utf-8
+
+=head1 NAME
+
+libev - a high performance full-featured event loop written in C
+
+=head1 SYNOPSIS
+
+ #include <ev.h>
+
+=head2 EXAMPLE PROGRAM
+
+ // a single header file is required
+ #include <ev.h>
+
+ #include <stdio.h> // for puts
+
+ // every watcher type has its own typedef'd struct
+ // with the name ev_TYPE
+ ev_io stdin_watcher;
+ ev_timer timeout_watcher;
+
+ // all watcher callbacks have a similar signature
+ // this callback is called when data is readable on stdin
+ static void
+ stdin_cb (EV_P_ ev_io *w, int revents)
+ {
+ puts ("stdin ready");
+ // for one-shot events, one must manually stop the watcher
+ // with its corresponding stop function.
+ ev_io_stop (EV_A_ w);
+
+ // this causes all nested ev_run's to stop iterating
+ ev_break (EV_A_ EVBREAK_ALL);
+ }
+
+ // another callback, this time for a time-out
+ static void
+ timeout_cb (EV_P_ ev_timer *w, int revents)
+ {
+ puts ("timeout");
+ // this causes the innermost ev_run to stop iterating
+ ev_break (EV_A_ EVBREAK_ONE);
+ }
+
+ int
+ main (void)
+ {
+ // use the default event loop unless you have special needs
+ struct ev_loop *loop = EV_DEFAULT;
+
+ // initialise an io watcher, then start it
+ // this one will watch for stdin to become readable
+ ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
+ ev_io_start (loop, &stdin_watcher);
+
+ // initialise a timer watcher, then start it
+ // simple non-repeating 5.5 second timeout
+ ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+ ev_timer_start (loop, &timeout_watcher);
+
+ // now wait for events to arrive
+ ev_run (loop, 0);
+
+ // break was called, so exit
+ return 0;
+ }
+
+=head1 ABOUT THIS DOCUMENT
+
+This document documents the libev software package.
+
+The newest version of this document is also available as an html-formatted
+web page you might find easier to navigate when reading it for the first
+time: L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>.
+
+While this document tries to be as complete as possible in documenting
+libev, its usage and the rationale behind its design, it is not a tutorial
+on event-based programming, nor will it introduce event-based programming
+with libev.
+
+Familiarity with event based programming techniques in general is assumed
+throughout this document.
+
+=head1 WHAT TO READ WHEN IN A HURRY
+
+This manual tries to be very detailed, but unfortunately, this also makes
+it very long. If you just want to know the basics of libev, I suggest
+reading L</ANATOMY OF A WATCHER>, then the L</EXAMPLE PROGRAM> above and
+look up the missing functions in L</GLOBAL FUNCTIONS> and the C<ev_io> and
+C<ev_timer> sections in L</WATCHER TYPES>.
+
+=head1 ABOUT LIBEV
+
+Libev is an event loop: you register interest in certain events (such as a
+file descriptor being readable or a timeout occurring), and it will manage
+these event sources and provide your program with events.
+
+To do this, it must take more or less complete control over your process
+(or thread) by executing the I<event loop> handler, and will then
+communicate events via a callback mechanism.
+
+You register interest in certain events by registering so-called I<event
+watchers>, which are relatively small C structures you initialise with the
+details of the event, and then hand it over to libev by I<starting> the
+watcher.
+
+=head2 FEATURES
+
+Libev supports C<select>, C<poll>, the Linux-specific aio and C<epoll>
+interfaces, the BSD-specific C<kqueue> and the Solaris-specific event port
+mechanisms for file descriptor events (C<ev_io>), the Linux C<inotify>
+interface (for C<ev_stat>), Linux eventfd/signalfd (for faster and cleaner
+inter-thread wakeup (C<ev_async>)/signal handling (C<ev_signal>)) relative
+timers (C<ev_timer>), absolute timers with customised rescheduling
+(C<ev_periodic>), synchronous signals (C<ev_signal>), process status
+change events (C<ev_child>), and event watchers dealing with the event
+loop mechanism itself (C<ev_idle>, C<ev_embed>, C<ev_prepare> and
+C<ev_check> watchers) as well as file watchers (C<ev_stat>) and even
+limited support for fork events (C<ev_fork>).
+
+It also is quite fast (see this
+L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent
+for example).
+
+=head2 CONVENTIONS
+
+Libev is very configurable. In this manual the default (and most common)
+configuration will be described, which supports multiple event loops. For
+more info about various configuration options please have a look at
+B<EMBED> section in this manual. If libev was configured without support
+for multiple event loops, then all functions taking an initial argument of
+name C<loop> (which is always of type C<struct ev_loop *>) will not have
+this argument.
+
+=head2 TIME REPRESENTATION
+
+Libev represents time as a single floating point number, representing
+the (fractional) number of seconds since the (POSIX) epoch (in practice
+somewhere near the beginning of 1970, details are complicated, don't
+ask). This type is called C<ev_tstamp>, which is what you should use
+too. It usually aliases to the C<double> type in C. When you need to do
+any calculations on it, you should treat it as some floating point value.
+
+Unlike the name component C<stamp> might indicate, it is also used for
+time differences (e.g. delays) throughout libev.
+
+=head1 ERROR HANDLING
+
+Libev knows three classes of errors: operating system errors, usage errors
+and internal errors (bugs).
+
+When libev catches an operating system error it cannot handle (for example
+a system call indicating a condition libev cannot fix), it calls the callback
+set via C<ev_set_syserr_cb>, which is supposed to fix the problem or
+abort. The default is to print a diagnostic message and to call C<abort
+()>.
+
+When libev detects a usage error such as a negative timer interval, then
+it will print a diagnostic message and abort (via the C<assert> mechanism,
+so C<NDEBUG> will disable this checking): these are programming errors in
+the libev caller and need to be fixed there.
+
+Via the C<EV_FREQUENT> macro you can compile in and/or enable extensive
+consistency checking code inside libev that can be used to check for
+internal inconsistencies, suually caused by application bugs.
+
+Libev also has a few internal error-checking C<assert>ions. These do not
+trigger under normal circumstances, as they indicate either a bug in libev
+or worse.
+
+
+=head1 GLOBAL FUNCTIONS
+
+These functions can be called anytime, even before initialising the
+library in any way.
+
+=over 4
+
+=item ev_tstamp ev_time ()
+
+Returns the current time as libev would use it. Please note that the
+C<ev_now> function is usually faster and also often returns the timestamp
+you actually want to know. Also interesting is the combination of
+C<ev_now_update> and C<ev_now>.
+
+=item ev_sleep (ev_tstamp interval)
+
+Sleep for the given interval: The current thread will be blocked
+until either it is interrupted or the given time interval has
+passed (approximately - it might return a bit earlier even if not
+interrupted). Returns immediately if C<< interval <= 0 >>.
+
+Basically this is a sub-second-resolution C<sleep ()>.
+
+The range of the C<interval> is limited - libev only guarantees to work
+with sleep times of up to one day (C<< interval <= 86400 >>).
+
+=item int ev_version_major ()
+
+=item int ev_version_minor ()
+
+You can find out the major and minor ABI version numbers of the library
+you linked against by calling the functions C<ev_version_major> and
+C<ev_version_minor>. If you want, you can compare against the global
+symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the
+version of the library your program was compiled against.
+
+These version numbers refer to the ABI version of the library, not the
+release version.
+
+Usually, it's a good idea to terminate if the major versions mismatch,
+as this indicates an incompatible change. Minor versions are usually
+compatible to older versions, so a larger minor version alone is usually
+not a problem.
+
+Example: Make sure we haven't accidentally been linked against the wrong
+version (note, however, that this will not detect other ABI mismatches,
+such as LFS or reentrancy).
+
+ assert (("libev version mismatch",
+ ev_version_major () == EV_VERSION_MAJOR
+ && ev_version_minor () >= EV_VERSION_MINOR));
+
+=item unsigned int ev_supported_backends ()
+
+Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*>
+value) compiled into this binary of libev (independent of their
+availability on the system you are running on). See C<ev_default_loop> for
+a description of the set values.
+
+Example: make sure we have the epoll method, because yeah this is cool and
+a must have and can we have a torrent of it please!!!11
+
+ assert (("sorry, no epoll, no sex",
+ ev_supported_backends () & EVBACKEND_EPOLL));
+
+=item unsigned int ev_recommended_backends ()
+
+Return the set of all backends compiled into this binary of libev and
+also recommended for this platform, meaning it will work for most file
+descriptor types. This set is often smaller than the one returned by
+C<ev_supported_backends>, as for example kqueue is broken on most BSDs
+and will not be auto-detected unless you explicitly request it (assuming
+you know what you are doing). This is the set of backends that libev will
+probe for if you specify no backends explicitly.
+
+=item unsigned int ev_embeddable_backends ()
+
+Returns the set of backends that are embeddable in other event loops. This
+value is platform-specific but can include backends not available on the
+current system. To find which embeddable backends might be supported on
+the current system, you would need to look at C<ev_embeddable_backends ()
+& ev_supported_backends ()>, likewise for recommended ones.
+
+See the description of C<ev_embed> watchers for more info.
+
+=item ev_set_allocator (void *(*cb)(void *ptr, long size) throw ())
+
+Sets the allocation function to use (the prototype is similar - the
+semantics are identical to the C<realloc> C89/SuS/POSIX function). It is
+used to allocate and free memory (no surprises here). If it returns zero
+when memory needs to be allocated (C<size != 0>), the library might abort
+or take some potentially destructive action.
+
+Since some systems (at least OpenBSD and Darwin) fail to implement
+correct C<realloc> semantics, libev will use a wrapper around the system
+C<realloc> and C<free> functions by default.
+
+You could override this function in high-availability programs to, say,
+free some memory if it cannot allocate memory, to use a special allocator,
+or even to sleep a while and retry until some memory is available.
+
+Example: The following is the C<realloc> function that libev itself uses
+which should work with C<realloc> and C<free> functions of all kinds and
+is probably a good basis for your own implementation.
+
+ static void *
+ ev_realloc_emul (void *ptr, long size) EV_NOEXCEPT
+ {
+ if (size)
+ return realloc (ptr, size);
+
+ free (ptr);
+ return 0;
+ }
+
+Example: Replace the libev allocator with one that waits a bit and then
+retries.
+
+ static void *
+ persistent_realloc (void *ptr, size_t size)
+ {
+ if (!size)
+ {
+ free (ptr);
+ return 0;
+ }
+
+ for (;;)
+ {
+ void *newptr = realloc (ptr, size);
+
+ if (newptr)
+ return newptr;
+
+ sleep (60);
+ }
+ }
+
+ ...
+ ev_set_allocator (persistent_realloc);
+
+=item ev_set_syserr_cb (void (*cb)(const char *msg) throw ())
+
+Set the callback function to call on a retryable system call error (such
+as failed select, poll, epoll_wait). The message is a printable string
+indicating the system call or subsystem causing the problem. If this
+callback is set, then libev will expect it to remedy the situation, no
+matter what, when it returns. That is, libev will generally retry the
+requested operation, or, if the condition doesn't go away, do bad stuff
+(such as abort).
+
+Example: This is basically the same thing that libev does internally, too.
+
+ static void
+ fatal_error (const char *msg)
+ {
+ perror (msg);
+ abort ();
+ }
+
+ ...
+ ev_set_syserr_cb (fatal_error);
+
+=item ev_feed_signal (int signum)
+
+This function can be used to "simulate" a signal receive. It is completely
+safe to call this function at any time, from any context, including signal
+handlers or random threads.
+
+Its main use is to customise signal handling in your process, especially
+in the presence of threads. For example, you could block signals
+by default in all threads (and specifying C<EVFLAG_NOSIGMASK> when
+creating any loops), and in one thread, use C<sigwait> or any other
+mechanism to wait for signals, then "deliver" them to libev by calling
+C<ev_feed_signal>.
+
+=back
+
+=head1 FUNCTIONS CONTROLLING EVENT LOOPS
+
+An event loop is described by a C<struct ev_loop *> (the C<struct> is
+I<not> optional in this case unless libev 3 compatibility is disabled, as
+libev 3 had an C<ev_loop> function colliding with the struct name).
+
+The library knows two types of such loops, the I<default> loop, which
+supports child process events, and dynamically created event loops which
+do not.
+
+=over 4
+
+=item struct ev_loop *ev_default_loop (unsigned int flags)
+
+This returns the "default" event loop object, which is what you should
+normally use when you just need "the event loop". Event loop objects and
+the C<flags> parameter are described in more detail in the entry for
+C<ev_loop_new>.
+
+If the default loop is already initialised then this function simply
+returns it (and ignores the flags. If that is troubling you, check
+C<ev_backend ()> afterwards). Otherwise it will create it with the given
+flags, which should almost always be C<0>, unless the caller is also the
+one calling C<ev_run> or otherwise qualifies as "the main program".
+
+If you don't know what event loop to use, use the one returned from this
+function (or via the C<EV_DEFAULT> macro).
+
+Note that this function is I<not> thread-safe, so if you want to use it
+from multiple threads, you have to employ some kind of mutex (note also
+that this case is unlikely, as loops cannot be shared easily between
+threads anyway).
+
+The default loop is the only loop that can handle C<ev_child> watchers,
+and to do this, it always registers a handler for C<SIGCHLD>. If this is
+a problem for your application you can either create a dynamic loop with
+C<ev_loop_new> which doesn't do that, or you can simply overwrite the
+C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
+
+Example: This is the most typical usage.
+
+ if (!ev_default_loop (0))
+ fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
+
+Example: Restrict libev to the select and poll backends, and do not allow
+environment settings to be taken into account:
+
+ ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
+
+=item struct ev_loop *ev_loop_new (unsigned int flags)
+
+This will create and initialise a new event loop object. If the loop
+could not be initialised, returns false.
+
+This function is thread-safe, and one common way to use libev with
+threads is indeed to create one loop per thread, and using the default
+loop in the "main" or "initial" thread.
+
+The flags argument can be used to specify special behaviour or specific
+backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
+
+The following flags are supported:
+
+=over 4
+
+=item C<EVFLAG_AUTO>
+
+The default flags value. Use this if you have no clue (it's the right
+thing, believe me).
+
+=item C<EVFLAG_NOENV>
+
+If this flag bit is or'ed into the flag value (or the program runs setuid
+or setgid) then libev will I<not> look at the environment variable
+C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
+override the flags completely if it is found in the environment. This is
+useful to try out specific backends to test their performance, to work
+around bugs, or to make libev threadsafe (accessing environment variables
+cannot be done in a threadsafe way, but usually it works if no other
+thread modifies them).
+
+=item C<EVFLAG_FORKCHECK>
+
+Instead of calling C<ev_loop_fork> manually after a fork, you can also
+make libev check for a fork in each iteration by enabling this flag.
+
+This works by calling C<getpid ()> on every iteration of the loop,
+and thus this might slow down your event loop if you do a lot of loop
+iterations and little real work, but is usually not noticeable (on my
+GNU/Linux system for example, C<getpid> is actually a simple 5-insn
+sequence without a system call and thus I<very> fast, but my GNU/Linux
+system also has C<pthread_atfork> which is even faster). (Update: glibc
+versions 2.25 apparently removed the C<getpid> optimisation again).
+
+The big advantage of this flag is that you can forget about fork (and
+forget about forgetting to tell libev about forking, although you still
+have to ignore C<SIGPIPE>) when you use this flag.
+
+This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS>
+environment variable.
+
+=item C<EVFLAG_NOINOTIFY>
+
+When this flag is specified, then libev will not attempt to use the
+I<inotify> API for its C<ev_stat> watchers. Apart from debugging and
+testing, this flag can be useful to conserve inotify file descriptors, as
+otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
+
+=item C<EVFLAG_SIGNALFD>
+
+When this flag is specified, then libev will attempt to use the
+I<signalfd> API for its C<ev_signal> (and C<ev_child>) watchers. This API
+delivers signals synchronously, which makes it both faster and might make
+it possible to get the queued signal data. It can also simplify signal
+handling with threads, as long as you properly block signals in your
+threads that are not interested in handling them.
+
+Signalfd will not be used by default as this changes your signal mask, and
+there are a lot of shoddy libraries and programs (glib's threadpool for
+example) that can't properly initialise their signal masks.
+
+=item C<EVFLAG_NOSIGMASK>
+
+When this flag is specified, then libev will avoid to modify the signal
+mask. Specifically, this means you have to make sure signals are unblocked
+when you want to receive them.
+
+This behaviour is useful when you want to do your own signal handling, or
+want to handle signals only in specific threads and want to avoid libev
+unblocking the signals.
+
+It's also required by POSIX in a threaded program, as libev calls
+C<sigprocmask>, whose behaviour is officially unspecified.
+
+=item C<EVFLAG_NOTIMERFD>
+
+When this flag is specified, the libev will avoid using a C<timerfd> to
+detect time jumps. It will still be able to detect time jumps, but takes
+longer and has a lower accuracy in doing so, but saves a file descriptor
+per loop.
+
+The current implementation only tries to use a C<timerfd> when the first
+C<ev_periodic> watcher is started and falls back on other methods if it
+cannot be created, but this behaviour might change in the future.
+
+=item C<EVBACKEND_SELECT> (value 1, portable select backend)
+
+This is your standard select(2) backend. Not I<completely> standard, as
+libev tries to roll its own fd_set with no limits on the number of fds,
+but if that fails, expect a fairly low limit on the number of fds when
+using this backend. It doesn't scale too well (O(highest_fd)), but its
+usually the fastest backend for a low number of (low-numbered :) fds.
+
+To get good performance out of this backend you need a high amount of
+parallelism (most of the file descriptors should be busy). If you are
+writing a server, you should C<accept ()> in a loop to accept as many
+connections as possible during one iteration. You might also want to have
+a look at C<ev_set_io_collect_interval ()> to increase the amount of
+readiness notifications you get per iteration.
+
+This backend maps C<EV_READ> to the C<readfds> set and C<EV_WRITE> to the
+C<writefds> set (and to work around Microsoft Windows bugs, also onto the
+C<exceptfds> set on that platform).
+
+=item C<EVBACKEND_POLL> (value 2, poll backend, available everywhere except on windows)
+
+And this is your standard poll(2) backend. It's more complicated
+than select, but handles sparse fds better and has no artificial
+limit on the number of fds you can use (except it will slow down
+considerably with a lot of inactive fds). It scales similarly to select,
+i.e. O(total_fds). See the entry for C<EVBACKEND_SELECT>, above, for
+performance tips.
+
+This backend maps C<EV_READ> to C<POLLIN | POLLERR | POLLHUP>, and
+C<EV_WRITE> to C<POLLOUT | POLLERR | POLLHUP>.
+
+=item C<EVBACKEND_EPOLL> (value 4, Linux)
+
+Use the Linux-specific epoll(7) interface (for both pre- and post-2.6.9
+kernels).
+
+For few fds, this backend is a bit little slower than poll and select, but
+it scales phenomenally better. While poll and select usually scale like
+O(total_fds) where total_fds is the total number of fds (or the highest
+fd), epoll scales either O(1) or O(active_fds).
+
+The epoll mechanism deserves honorable mention as the most misdesigned
+of the more advanced event mechanisms: mere annoyances include silently
+dropping file descriptors, requiring a system call per change per file
+descriptor (and unnecessary guessing of parameters), problems with dup,
+returning before the timeout value, resulting in additional iterations
+(and only giving 5ms accuracy while select on the same platform gives
+0.1ms) and so on. The biggest issue is fork races, however - if a program
+forks then I<both> parent and child process have to recreate the epoll
+set, which can take considerable time (one syscall per file descriptor)
+and is of course hard to detect.
+
+Epoll is also notoriously buggy - embedding epoll fds I<should> work,
+but of course I<doesn't>, and epoll just loves to report events for
+totally I<different> file descriptors (even already closed ones, so
+one cannot even remove them from the set) than registered in the set
+(especially on SMP systems). Libev tries to counter these spurious
+notifications by employing an additional generation counter and comparing
+that against the events to filter out spurious ones, recreating the set
+when required. Epoll also erroneously rounds down timeouts, but gives you
+no way to know when and by how much, so sometimes you have to busy-wait
+because epoll returns immediately despite a nonzero timeout. And last
+not least, it also refuses to work with some file descriptors which work
+perfectly fine with C<select> (files, many character devices...).
+
+Epoll is truly the train wreck among event poll mechanisms, a frankenpoll,
+cobbled together in a hurry, no thought to design or interaction with
+others. Oh, the pain, will it ever stop...
+
+While stopping, setting and starting an I/O watcher in the same iteration
+will result in some caching, there is still a system call per such
+incident (because the same I<file descriptor> could point to a different
+I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
+file descriptors might not work very well if you register events for both
+file descriptors.
+
+Best performance from this backend is achieved by not unregistering all
+watchers for a file descriptor until it has been closed, if possible,
+i.e. keep at least one watcher active per fd at all times. Stopping and
+starting a watcher (without re-setting it) also usually doesn't cause
+extra overhead. A fork can both result in spurious notifications as well
+as in libev having to destroy and recreate the epoll object, which can
+take considerable time and thus should be avoided.
+
+All this means that, in practice, C<EVBACKEND_SELECT> can be as fast or
+faster than epoll for maybe up to a hundred file descriptors, depending on
+the usage. So sad.
+
+While nominally embeddable in other event loops, this feature is broken in
+a lot of kernel revisions, but probably(!) works in current versions.
+
+This backend maps C<EV_READ> and C<EV_WRITE> in the same way as
+C<EVBACKEND_POLL>.
+
+=item C<EVBACKEND_LINUXAIO> (value 64, Linux)
+
+Use the Linux-specific Linux AIO (I<not> C<< aio(7) >> but C<<
+io_submit(2) >>) event interface available in post-4.18 kernels (but libev
+only tries to use it in 4.19+).
+
+This is another Linux train wreck of an event interface.
+
+If this backend works for you (as of this writing, it was very
+experimental), it is the best event interface available on Linux and might
+be well worth enabling it - if it isn't available in your kernel this will
+be detected and this backend will be skipped.
+
+This backend can batch oneshot requests and supports a user-space ring
+buffer to receive events. It also doesn't suffer from most of the design
+problems of epoll (such as not being able to remove event sources from
+the epoll set), and generally sounds too good to be true. Because, this
+being the Linux kernel, of course it suffers from a whole new set of
+limitations, forcing you to fall back to epoll, inheriting all its design
+issues.
+
+For one, it is not easily embeddable (but probably could be done using
+an event fd at some extra overhead). It also is subject to a system wide
+limit that can be configured in F</proc/sys/fs/aio-max-nr>. If no AIO
+requests are left, this backend will be skipped during initialisation, and
+will switch to epoll when the loop is active.
+
+Most problematic in practice, however, is that not all file descriptors
+work with it. For example, in Linux 5.1, TCP sockets, pipes, event fds,
+files, F</dev/null> and many others are supported, but ttys do not work
+properly (a known bug that the kernel developers don't care about, see
+L<https://lore.kernel.org/patchwork/patch/1047453/>), so this is not
+(yet?) a generic event polling interface.
+
+Overall, it seems the Linux developers just don't want it to have a
+generic event handling mechanism other than C<select> or C<poll>.
+
+To work around all these problem, the current version of libev uses its
+epoll backend as a fallback for file descriptor types that do not work. Or
+falls back completely to epoll if the kernel acts up.
+
+This backend maps C<EV_READ> and C<EV_WRITE> in the same way as
+C<EVBACKEND_POLL>.
+
+=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)
+
+Kqueue deserves special mention, as at the time this backend was
+implemented, it was broken on all BSDs except NetBSD (usually it doesn't
+work reliably with anything but sockets and pipes, except on Darwin,
+where of course it's completely useless). Unlike epoll, however, whose
+brokenness is by design, these kqueue bugs can be (and mostly have been)
+fixed without API changes to existing programs. For this reason it's not
+being "auto-detected" on all platforms unless you explicitly specify it
+in the flags (i.e. using C<EVBACKEND_KQUEUE>) or libev was compiled on a
+known-to-be-good (-enough) system like NetBSD.
+
+You still can embed kqueue into a normal poll or select backend and use it
+only for sockets (after having made sure that sockets work with kqueue on
+the target platform). See C<ev_embed> watchers for more info.
+
+It scales in the same way as the epoll backend, but the interface to the
+kernel is more efficient (which says nothing about its actual speed, of
+course). While stopping, setting and starting an I/O watcher does never
+cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to
+two event changes per incident. Support for C<fork ()> is very bad (you
+might have to leak fds on fork, but it's more sane than epoll) and it
+drops fds silently in similarly hard-to-detect cases.
+
+This backend usually performs well under most conditions.
+
+While nominally embeddable in other event loops, this doesn't work
+everywhere, so you might need to test for this. And since it is broken
+almost everywhere, you should only use it when you have a lot of sockets
+(for which it usually works), by embedding it into another event loop
+(e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> (but C<poll> is of course
+also broken on OS X)) and, did I mention it, using it only for sockets.
+
+This backend maps C<EV_READ> into an C<EVFILT_READ> kevent with
+C<NOTE_EOF>, and C<EV_WRITE> into an C<EVFILT_WRITE> kevent with
+C<NOTE_EOF>.
+
+=item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8)
+
+This is not implemented yet (and might never be, unless you send me an
+implementation). According to reports, C</dev/poll> only supports sockets
+and is not embeddable, which would limit the usefulness of this backend
+immensely.
+
+=item C<EVBACKEND_PORT> (value 32, Solaris 10)
+
+This uses the Solaris 10 event port mechanism. As with everything on Solaris,
+it's really slow, but it still scales very well (O(active_fds)).
+
+While this backend scales well, it requires one system call per active
+file descriptor per loop iteration. For small and medium numbers of file
+descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend
+might perform better.
+
+On the positive side, this backend actually performed fully to
+specification in all tests and is fully embeddable, which is a rare feat
+among the OS-specific backends (I vastly prefer correctness over speed
+hacks).
+
+On the negative side, the interface is I<bizarre> - so bizarre that
+even sun itself gets it wrong in their code examples: The event polling
+function sometimes returns events to the caller even though an error
+occurred, but with no indication whether it has done so or not (yes, it's
+even documented that way) - deadly for edge-triggered interfaces where you
+absolutely have to know whether an event occurred or not because you have
+to re-arm the watcher.
+
+Fortunately libev seems to be able to work around these idiocies.
+
+This backend maps C<EV_READ> and C<EV_WRITE> in the same way as
+C<EVBACKEND_POLL>.
+
+=item C<EVBACKEND_ALL>
+
+Try all backends (even potentially broken ones that wouldn't be tried
+with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as
+C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.
+
+It is definitely not recommended to use this flag, use whatever
+C<ev_recommended_backends ()> returns, or simply do not specify a backend
+at all.
+
+=item C<EVBACKEND_MASK>
+
+Not a backend at all, but a mask to select all backend bits from a
+C<flags> value, in case you want to mask out any backends from a flags
+value (e.g. when modifying the C<LIBEV_FLAGS> environment variable).
+
+=back
+
+If one or more of the backend flags are or'ed into the flags value,
+then only these backends will be tried (in the reverse order as listed
+here). If none are specified, all backends in C<ev_recommended_backends
+()> will be tried.
+
+Example: Try to create a event loop that uses epoll and nothing else.
+
+ struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
+ if (!epoller)
+ fatal ("no epoll found here, maybe it hides under your chair");
+
+Example: Use whatever libev has to offer, but make sure that kqueue is
+used if available.
+
+ struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
+
+Example: Similarly, on linux, you mgiht want to take advantage of the
+linux aio backend if possible, but fall back to something else if that
+isn't available.
+
+ struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_LINUXAIO);
+
+=item ev_loop_destroy (loop)
+
+Destroys an event loop object (frees all memory and kernel state
+etc.). None of the active event watchers will be stopped in the normal
+sense, so e.g. C<ev_is_active> might still return true. It is your
+responsibility to either stop all watchers cleanly yourself I<before>
+calling this function, or cope with the fact afterwards (which is usually
+the easiest thing, you can just ignore the watchers and/or C<free ()> them
+for example).
+
+Note that certain global state, such as signal state (and installed signal
+handlers), will not be freed by this function, and related watchers (such
+as signal and child watchers) would need to be stopped manually.
+
+This function is normally used on loop objects allocated by
+C<ev_loop_new>, but it can also be used on the default loop returned by
+C<ev_default_loop>, in which case it is not thread-safe.
+
+Note that it is not advisable to call this function on the default loop
+except in the rare occasion where you really need to free its resources.
+If you need dynamically allocated loops it is better to use C<ev_loop_new>
+and C<ev_loop_destroy>.
+
+=item ev_loop_fork (loop)
+
+This function sets a flag that causes subsequent C<ev_run> iterations
+to reinitialise the kernel state for backends that have one. Despite
+the name, you can call it anytime you are allowed to start or stop
+watchers (except inside an C<ev_prepare> callback), but it makes most
+sense after forking, in the child process. You I<must> call it (or use
+C<EVFLAG_FORKCHECK>) in the child before resuming or calling C<ev_run>.
+
+In addition, if you want to reuse a loop (via this function or
+C<EVFLAG_FORKCHECK>), you I<also> have to ignore C<SIGPIPE>.
+
+Again, you I<have> to call it on I<any> loop that you want to re-use after
+a fork, I<even if you do not plan to use the loop in the parent>. This is
+because some kernel interfaces *cough* I<kqueue> *cough* do funny things
+during fork.
+
+On the other hand, you only need to call this function in the child
+process if and only if you want to use the event loop in the child. If
+you just fork+exec or create a new loop in the child, you don't have to
+call it at all (in fact, C<epoll> is so badly broken that it makes a
+difference, but libev will usually detect this case on its own and do a
+costly reset of the backend).
+
+The function itself is quite fast and it's usually not a problem to call
+it just in case after a fork.
+
+Example: Automate calling C<ev_loop_fork> on the default loop when
+using pthreads.
+
+ static void
+ post_fork_child (void)
+ {
+ ev_loop_fork (EV_DEFAULT);
+ }
+
+ ...
+ pthread_atfork (0, 0, post_fork_child);
+
+=item int ev_is_default_loop (loop)
+
+Returns true when the given loop is, in fact, the default loop, and false
+otherwise.
+
+=item unsigned int ev_iteration (loop)
+
+Returns the current iteration count for the event loop, which is identical
+to the number of times libev did poll for new events. It starts at C<0>
+and happily wraps around with enough iterations.
+
+This value can sometimes be useful as a generation counter of sorts (it
+"ticks" the number of loop iterations), as it roughly corresponds with
+C<ev_prepare> and C<ev_check> calls - and is incremented between the
+prepare and check phases.
+
+=item unsigned int ev_depth (loop)
+
+Returns the number of times C<ev_run> was entered minus the number of
+times C<ev_run> was exited normally, in other words, the recursion depth.
+
+Outside C<ev_run>, this number is zero. In a callback, this number is
+C<1>, unless C<ev_run> was invoked recursively (or from another thread),
+in which case it is higher.
+
+Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread,
+throwing an exception etc.), doesn't count as "exit" - consider this
+as a hint to avoid such ungentleman-like behaviour unless it's really
+convenient, in which case it is fully supported.
+
+=item unsigned int ev_backend (loop)
+
+Returns one of the C<EVBACKEND_*> flags indicating the event backend in
+use.
+
+=item ev_tstamp ev_now (loop)
+
+Returns the current "event loop time", which is the time the event loop
+received events and started processing them. This timestamp does not
+change as long as callbacks are being processed, and this is also the base
+time used for relative timers. You can treat it as the timestamp of the
+event occurring (or more correctly, libev finding out about it).
+
+=item ev_now_update (loop)
+
+Establishes the current time by querying the kernel, updating the time
+returned by C<ev_now ()> in the progress. This is a costly operation and
+is usually done automatically within C<ev_run ()>.
+
+This function is rarely useful, but when some event callback runs for a
+very long time without entering the event loop, updating libev's idea of
+the current time is a good idea.
+
+See also L</The special problem of time updates> in the C<ev_timer> section.
+
+=item ev_suspend (loop)
+
+=item ev_resume (loop)
+
+These two functions suspend and resume an event loop, for use when the
+loop is not used for a while and timeouts should not be processed.
+
+A typical use case would be an interactive program such as a game: When
+the user presses C<^Z> to suspend the game and resumes it an hour later it
+would be best to handle timeouts as if no time had actually passed while
+the program was suspended. This can be achieved by calling C<ev_suspend>
+in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
+C<ev_resume> directly afterwards to resume timer processing.
+
+Effectively, all C<ev_timer> watchers will be delayed by the time spend
+between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
+will be rescheduled (that is, they will lose any events that would have
+occurred while suspended).
+
+After calling C<ev_suspend> you B<must not> call I<any> function on the
+given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
+without a previous call to C<ev_suspend>.
+
+Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
+event loop time (see C<ev_now_update>).
+
+=item bool ev_run (loop, int flags)
+
+Finally, this is it, the event handler. This function usually is called
+after you have initialised all your watchers and you want to start
+handling events. It will ask the operating system for any new events, call
+the watcher callbacks, and then repeat the whole process indefinitely: This
+is why event loops are called I<loops>.
+
+If the flags argument is specified as C<0>, it will keep handling events
+until either no event watchers are active anymore or C<ev_break> was
+called.
+
+The return value is false if there are no more active watchers (which
+usually means "all jobs done" or "deadlock"), and true in all other cases
+(which usually means " you should call C<ev_run> again").
+
+Please note that an explicit C<ev_break> is usually better than
+relying on all watchers to be stopped when deciding when a program has
+finished (especially in interactive programs), but having a program
+that automatically loops as long as it has to and no longer by virtue
+of relying on its watchers stopping correctly, that is truly a thing of
+beauty.
+
+This function is I<mostly> exception-safe - you can break out of a
+C<ev_run> call by calling C<longjmp> in a callback, throwing a C++
+exception and so on. This does not decrement the C<ev_depth> value, nor
+will it clear any outstanding C<EVBREAK_ONE> breaks.
+
+A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
+those events and any already outstanding ones, but will not wait and
+block your process in case there are no events and will return after one
+iteration of the loop. This is sometimes useful to poll and handle new
+events while doing lengthy calculations, to keep the program responsive.
+
+A flags value of C<EVRUN_ONCE> will look for new events (waiting if
+necessary) and will handle those and any already outstanding ones. It
+will block your process until at least one new event arrives (which could
+be an event internal to libev itself, so there is no guarantee that a
+user-registered callback will be called), and will return after one
+iteration of the loop.
+
+This is useful if you are waiting for some external event in conjunction
+with something not expressible using other libev watchers (i.e. "roll your
+own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
+usually a better approach for this kind of thing.
+
+Here are the gory details of what C<ev_run> does (this is for your
+understanding, not a guarantee that things will work exactly like this in
+future versions):
+
+ - Increment loop depth.
+ - Reset the ev_break status.
+ - Before the first iteration, call any pending watchers.
+ LOOP:
+ - If EVFLAG_FORKCHECK was used, check for a fork.
+ - If a fork was detected (by any means), queue and call all fork watchers.
+ - Queue and call all prepare watchers.
+ - If ev_break was called, goto FINISH.
+ - If we have been forked, detach and recreate the kernel state
+ as to not disturb the other process.
+ - Update the kernel state with all outstanding changes.
+ - Update the "event loop time" (ev_now ()).
+ - Calculate for how long to sleep or block, if at all
+ (active idle watchers, EVRUN_NOWAIT or not having
+ any active watchers at all will result in not sleeping).
+ - Sleep if the I/O and timer collect interval say so.
+ - Increment loop iteration counter.
+ - Block the process, waiting for any events.
+ - Queue all outstanding I/O (fd) events.
+ - Update the "event loop time" (ev_now ()), and do time jump adjustments.
+ - Queue all expired timers.
+ - Queue all expired periodics.
+ - Queue all idle watchers with priority higher than that of pending events.
+ - Queue all check watchers.
+ - Call all queued watchers in reverse order (i.e. check watchers first).
+ Signals and child watchers are implemented as I/O watchers, and will
+ be handled here by queueing them when their watcher gets executed.
+ - If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
+ were used, or there are no active watchers, goto FINISH, otherwise
+ continue with step LOOP.
+ FINISH:
+ - Reset the ev_break status iff it was EVBREAK_ONE.
+ - Decrement the loop depth.
+ - Return.
+
+Example: Queue some jobs and then loop until no events are outstanding
+anymore.
+
+ ... queue jobs here, make sure they register event watchers as long
+ ... as they still have work to do (even an idle watcher will do..)
+ ev_run (my_loop, 0);
+ ... jobs done or somebody called break. yeah!
+
+=item ev_break (loop, how)
+
+Can be used to make a call to C<ev_run> return early (but only after it
+has processed all outstanding events). The C<how> argument must be either
+C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
+C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
+
+This "break state" will be cleared on the next call to C<ev_run>.
+
+It is safe to call C<ev_break> from outside any C<ev_run> calls, too, in
+which case it will have no effect.
+
+=item ev_ref (loop)
+
+=item ev_unref (loop)
+
+Ref/unref can be used to add or remove a reference count on the event
+loop: Every watcher keeps one reference, and as long as the reference
+count is nonzero, C<ev_run> will not return on its own.
+
+This is useful when you have a watcher that you never intend to
+unregister, but that nevertheless should not keep C<ev_run> from
+returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
+before stopping it.
+
+As an example, libev itself uses this for its internal signal pipe: It
+is not visible to the libev user and should not keep C<ev_run> from
+exiting if no event watchers registered by it are active. It is also an
+excellent way to do this for generic recurring timers or from within
+third-party libraries. Just remember to I<unref after start> and I<ref
+before stop> (but only if the watcher wasn't active before, or was active
+before, respectively. Note also that libev might stop watchers itself
+(e.g. non-repeating timers) in which case you have to C<ev_ref>
+in the callback).
+
+Example: Create a signal watcher, but keep it from keeping C<ev_run>
+running when nothing else is active.
+
+ ev_signal exitsig;
+ ev_signal_init (&exitsig, sig_cb, SIGINT);
+ ev_signal_start (loop, &exitsig);
+ ev_unref (loop);
+
+Example: For some weird reason, unregister the above signal handler again.
+
+ ev_ref (loop);
+ ev_signal_stop (loop, &exitsig);
+
+=item ev_set_io_collect_interval (loop, ev_tstamp interval)
+
+=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)
+
+These advanced functions influence the time that libev will spend waiting
+for events. Both time intervals are by default C<0>, meaning that libev
+will try to invoke timer/periodic callbacks and I/O callbacks with minimum
+latency.
+
+Setting these to a higher value (the C<interval> I<must> be >= C<0>)
+allows libev to delay invocation of I/O and timer/periodic callbacks
+to increase efficiency of loop iterations (or to increase power-saving
+opportunities).
+
+The idea is that sometimes your program runs just fast enough to handle
+one (or very few) event(s) per loop iteration. While this makes the
+program responsive, it also wastes a lot of CPU time to poll for new
+events, especially with backends like C<select ()> which have a high
+overhead for the actual polling but can deliver many events at once.
+
+By setting a higher I<io collect interval> you allow libev to spend more
+time collecting I/O events, so you can handle more events per iteration,
+at the cost of increasing latency. Timeouts (both C<ev_periodic> and
+C<ev_timer>) will not be affected. Setting this to a non-null value will
+introduce an additional C<ev_sleep ()> call into most loop iterations. The
+sleep time ensures that libev will not poll for I/O events more often then
+once per this interval, on average (as long as the host time resolution is
+good enough).
+
+Likewise, by setting a higher I<timeout collect interval> you allow libev
+to spend more time collecting timeouts, at the expense of increased
+latency/jitter/inexactness (the watcher callback will be called
+later). C<ev_io> watchers will not be affected. Setting this to a non-null
+value will not introduce any overhead in libev.
+
+Many (busy) programs can usually benefit by setting the I/O collect
+interval to a value near C<0.1> or so, which is often enough for
+interactive servers (of course not for games), likewise for timeouts. It
+usually doesn't make much sense to set it to a lower value than C<0.01>,
+as this approaches the timing granularity of most systems. Note that if
+you do transactions with the outside world and you can't increase the
+parallelity, then this setting will limit your transaction rate (if you
+need to poll once per transaction and the I/O collect interval is 0.01,
+then you can't do more than 100 transactions per second).
+
+Setting the I<timeout collect interval> can improve the opportunity for
+saving power, as the program will "bundle" timer callback invocations that
+are "near" in time together, by delaying some, thus reducing the number of
+times the process sleeps and wakes up again. Another useful technique to
+reduce iterations/wake-ups is to use C<ev_periodic> watchers and make sure
+they fire on, say, one-second boundaries only.
+
+Example: we only need 0.1s timeout granularity, and we wish not to poll
+more often than 100 times per second:
+
+ ev_set_timeout_collect_interval (EV_DEFAULT_UC_ 0.1);
+ ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
+
+=item ev_invoke_pending (loop)
+
+This call will simply invoke all pending watchers while resetting their
+pending state. Normally, C<ev_run> does this automatically when required,
+but when overriding the invoke callback this call comes handy. This
+function can be invoked from a watcher - this can be useful for example
+when you want to do some lengthy calculation and want to pass further
+event handling to another thread (you still have to make sure only one
+thread executes within C<ev_invoke_pending> or C<ev_run> of course).
+
+=item int ev_pending_count (loop)
+
+Returns the number of pending watchers - zero indicates that no watchers
+are pending.
+
+=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
+
+This overrides the invoke pending functionality of the loop: Instead of
+invoking all pending watchers when there are any, C<ev_run> will call
+this callback instead. This is useful, for example, when you want to
+invoke the actual watchers inside another context (another thread etc.).
+
+If you want to reset the callback, use C<ev_invoke_pending> as new
+callback.
+
+=item ev_set_loop_release_cb (loop, void (*release)(EV_P) throw (), void (*acquire)(EV_P) throw ())
+
+Sometimes you want to share the same loop between multiple threads. This
+can be done relatively simply by putting mutex_lock/unlock calls around
+each call to a libev function.
+
+However, C<ev_run> can run an indefinite time, so it is not feasible
+to wait for it to return. One way around this is to wake up the event
+loop via C<ev_break> and C<ev_async_send>, another way is to set these
+I<release> and I<acquire> callbacks on the loop.
+
+When set, then C<release> will be called just before the thread is
+suspended waiting for new events, and C<acquire> is called just
+afterwards.
+
+Ideally, C<release> will just call your mutex_unlock function, and
+C<acquire> will just call the mutex_lock function again.
+
+While event loop modifications are allowed between invocations of
+C<release> and C<acquire> (that's their only purpose after all), no
+modifications done will affect the event loop, i.e. adding watchers will
+have no effect on the set of file descriptors being watched, or the time
+waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
+to take note of any changes you made.
+
+In theory, threads executing C<ev_run> will be async-cancel safe between
+invocations of C<release> and C<acquire>.
+
+See also the locking example in the C<THREADS> section later in this
+document.
+
+=item ev_set_userdata (loop, void *data)
+
+=item void *ev_userdata (loop)
+
+Set and retrieve a single C<void *> associated with a loop. When
+C<ev_set_userdata> has never been called, then C<ev_userdata> returns
+C<0>.
+
+These two functions can be used to associate arbitrary data with a loop,
+and are intended solely for the C<invoke_pending_cb>, C<release> and
+C<acquire> callbacks described above, but of course can be (ab-)used for
+any other purpose as well.
+
+=item ev_verify (loop)
+
+This function only does something when C<EV_VERIFY> support has been
+compiled in, which is the default for non-minimal builds. It tries to go
+through all internal structures and checks them for validity. If anything
+is found to be inconsistent, it will print an error message to standard
+error and call C<abort ()>.
+
+This can be used to catch bugs inside libev itself: under normal
+circumstances, this function will never abort as of course libev keeps its
+data structures consistent.
+
+=back
+
+
+=head1 ANATOMY OF A WATCHER
+
+In the following description, uppercase C<TYPE> in names stands for the
+watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
+watchers and C<ev_io_start> for I/O watchers.
+
+A watcher is an opaque structure that you allocate and register to record
+your interest in some event. To make a concrete example, imagine you want
+to wait for STDIN to become readable, you would create an C<ev_io> watcher
+for that:
+
+ static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
+ {
+ ev_io_stop (w);
+ ev_break (loop, EVBREAK_ALL);
+ }
+
+ struct ev_loop *loop = ev_default_loop (0);
+
+ ev_io stdin_watcher;
+
+ ev_init (&stdin_watcher, my_cb);
+ ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
+ ev_io_start (loop, &stdin_watcher);
+
+ ev_run (loop, 0);
+
+As you can see, you are responsible for allocating the memory for your
+watcher structures (and it is I<usually> a bad idea to do this on the
+stack).
+
+Each watcher has an associated watcher structure (called C<struct ev_TYPE>
+or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
+
+Each watcher structure must be initialised by a call to C<ev_init (watcher
+*, callback)>, which expects a callback to be provided. This callback is
+invoked each time the event occurs (or, in the case of I/O watchers, each
+time the event loop detects that the file descriptor given is readable
+and/or writable).
+
+Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
+macro to configure it, with arguments specific to the watcher type. There
+is also a macro to combine initialisation and setting in one call: C<<
+ev_TYPE_init (watcher *, callback, ...) >>.
+
+To make the watcher actually watch out for events, you have to start it
+with a watcher-specific start function (C<< ev_TYPE_start (loop, watcher
+*) >>), and you can stop watching for events at any time by calling the
+corresponding stop function (C<< ev_TYPE_stop (loop, watcher *) >>.
+
+As long as your watcher is active (has been started but not stopped) you
+must not touch the values stored in it except when explicitly documented
+otherwise. Most specifically you must never reinitialise it or call its
+C<ev_TYPE_set> macro.
+
+Each and every callback receives the event loop pointer as first, the
+registered watcher structure as second, and a bitset of received events as
+third argument.
+
+The received events usually include a single bit per event type received
+(you can receive multiple events at the same time). The possible bit masks
+are:
+
+=over 4
+
+=item C<EV_READ>
+
+=item C<EV_WRITE>
+
+The file descriptor in the C<ev_io> watcher has become readable and/or
+writable.
+
+=item C<EV_TIMER>
+
+The C<ev_timer> watcher has timed out.
+
+=item C<EV_PERIODIC>
+
+The C<ev_periodic> watcher has timed out.
+
+=item C<EV_SIGNAL>
+
+The signal specified in the C<ev_signal> watcher has been received by a thread.
+
+=item C<EV_CHILD>
+
+The pid specified in the C<ev_child> watcher has received a status change.
+
+=item C<EV_STAT>
+
+The path specified in the C<ev_stat> watcher changed its attributes somehow.
+
+=item C<EV_IDLE>
+
+The C<ev_idle> watcher has determined that you have nothing better to do.
+
+=item C<EV_PREPARE>
+
+=item C<EV_CHECK>
+
+All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts to
+gather new events, and all C<ev_check> watchers are queued (not invoked)
+just after C<ev_run> has gathered them, but before it queues any callbacks
+for any received events. That means C<ev_prepare> watchers are the last
+watchers invoked before the event loop sleeps or polls for new events, and
+C<ev_check> watchers will be invoked before any other watchers of the same
+or lower priority within an event loop iteration.
+
+Callbacks of both watcher types can start and stop as many watchers as
+they want, and all of them will be taken into account (for example, a
+C<ev_prepare> watcher might start an idle watcher to keep C<ev_run> from
+blocking).
+
+=item C<EV_EMBED>
+
+The embedded event loop specified in the C<ev_embed> watcher needs attention.
+
+=item C<EV_FORK>
+
+The event loop has been resumed in the child process after fork (see
+C<ev_fork>).
+
+=item C<EV_CLEANUP>
+
+The event loop is about to be destroyed (see C<ev_cleanup>).
+
+=item C<EV_ASYNC>
+
+The given async watcher has been asynchronously notified (see C<ev_async>).
+
+=item C<EV_CUSTOM>
+
+Not ever sent (or otherwise used) by libev itself, but can be freely used
+by libev users to signal watchers (e.g. via C<ev_feed_event>).
+
+=item C<EV_ERROR>
+
+An unspecified error has occurred, the watcher has been stopped. This might
+happen because the watcher could not be properly started because libev
+ran out of memory, a file descriptor was found to be closed or any other
+problem. Libev considers these application bugs.
+
+You best act on it by reporting the problem and somehow coping with the
+watcher being stopped. Note that well-written programs should not receive
+an error ever, so when your watcher receives it, this usually indicates a
+bug in your program.
+
+Libev will usually signal a few "dummy" events together with an error, for
+example it might indicate that a fd is readable or writable, and if your
+callbacks is well-written it can just attempt the operation and cope with
+the error from read() or write(). This will not work in multi-threaded
+programs, though, as the fd could already be closed and reused for another
+thing, so beware.
+
+=back
+
+=head2 GENERIC WATCHER FUNCTIONS
+
+=over 4
+
+=item C<ev_init> (ev_TYPE *watcher, callback)
+
+This macro initialises the generic portion of a watcher. The contents
+of the watcher object can be arbitrary (so C<malloc> will do). Only
+the generic parts of the watcher are initialised, you I<need> to call
+the type-specific C<ev_TYPE_set> macro afterwards to initialise the
+type-specific parts. For each type there is also a C<ev_TYPE_init> macro
+which rolls both calls into one.
+
+You can reinitialise a watcher at any time as long as it has been stopped
+(or never started) and there are no pending events outstanding.
+
+The callback is always of type C<void (*)(struct ev_loop *loop, ev_TYPE *watcher,
+int revents)>.
+
+Example: Initialise an C<ev_io> watcher in two steps.
+
+ ev_io w;
+ ev_init (&w, my_cb);
+ ev_io_set (&w, STDIN_FILENO, EV_READ);
+
+=item C<ev_TYPE_set> (ev_TYPE *watcher, [args])
+
+This macro initialises the type-specific parts of a watcher. You need to
+call C<ev_init> at least once before you call this macro, but you can
+call C<ev_TYPE_set> any number of times. You must not, however, call this
+macro on a watcher that is active (it can be pending, however, which is a
+difference to the C<ev_init> macro).
+
+Although some watcher types do not have type-specific arguments
+(e.g. C<ev_prepare>) you still need to call its C<set> macro.
+
+See C<ev_init>, above, for an example.
+
+=item C<ev_TYPE_init> (ev_TYPE *watcher, callback, [args])
+
+This convenience macro rolls both C<ev_init> and C<ev_TYPE_set> macro
+calls into a single call. This is the most convenient method to initialise
+a watcher. The same limitations apply, of course.
+
+Example: Initialise and set an C<ev_io> watcher in one step.
+
+ ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);
+
+=item C<ev_TYPE_start> (loop, ev_TYPE *watcher)
+
+Starts (activates) the given watcher. Only active watchers will receive
+events. If the watcher is already active nothing will happen.
+
+Example: Start the C<ev_io> watcher that is being abused as example in this
+whole section.
+
+ ev_io_start (EV_DEFAULT_UC, &w);
+
+=item C<ev_TYPE_stop> (loop, ev_TYPE *watcher)
+
+Stops the given watcher if active, and clears the pending status (whether
+the watcher was active or not).
+
+It is possible that stopped watchers are pending - for example,
+non-repeating timers are being stopped when they become pending - but
+calling C<ev_TYPE_stop> ensures that the watcher is neither active nor
+pending. If you want to free or reuse the memory used by the watcher it is
+therefore a good idea to always call its C<ev_TYPE_stop> function.
+
+=item bool ev_is_active (ev_TYPE *watcher)
+
+Returns a true value iff the watcher is active (i.e. it has been started
+and not yet been stopped). As long as a watcher is active you must not modify
+it.
+
+=item bool ev_is_pending (ev_TYPE *watcher)
+
+Returns a true value iff the watcher is pending, (i.e. it has outstanding
+events but its callback has not yet been invoked). As long as a watcher
+is pending (but not active) you must not call an init function on it (but
+C<ev_TYPE_set> is safe), you must not change its priority, and you must
+make sure the watcher is available to libev (e.g. you cannot C<free ()>
+it).
+
+=item callback ev_cb (ev_TYPE *watcher)
+
+Returns the callback currently set on the watcher.
+
+=item ev_set_cb (ev_TYPE *watcher, callback)
+
+Change the callback. You can change the callback at virtually any time
+(modulo threads).
+
+=item ev_set_priority (ev_TYPE *watcher, int priority)
+
+=item int ev_priority (ev_TYPE *watcher)
+
+Set and query the priority of the watcher. The priority is a small
+integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
+(default: C<-2>). Pending watchers with higher priority will be invoked
+before watchers with lower priority, but priority will not keep watchers
+from being executed (except for C<ev_idle> watchers).
+
+If you need to suppress invocation when higher priority events are pending
+you need to look at C<ev_idle> watchers, which provide this functionality.
+
+You I<must not> change the priority of a watcher as long as it is active or
+pending.
+
+Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
+fine, as long as you do not mind that the priority value you query might
+or might not have been clamped to the valid range.
+
+The default priority used by watchers when no priority has been set is
+always C<0>, which is supposed to not be too high and not be too low :).
+
+See L</WATCHER PRIORITY MODELS>, below, for a more thorough treatment of
+priorities.
+
+=item ev_invoke (loop, ev_TYPE *watcher, int revents)
+
+Invoke the C<watcher> with the given C<loop> and C<revents>. Neither
+C<loop> nor C<revents> need to be valid as long as the watcher callback
+can deal with that fact, as both are simply passed through to the
+callback.
+
+=item int ev_clear_pending (loop, ev_TYPE *watcher)
+
+If the watcher is pending, this function clears its pending status and
+returns its C<revents> bitset (as if its callback was invoked). If the
+watcher isn't pending it does nothing and returns C<0>.
+
+Sometimes it can be useful to "poll" a watcher instead of waiting for its
+callback to be invoked, which can be accomplished with this function.
+
+=item ev_feed_event (loop, ev_TYPE *watcher, int revents)
+
+Feeds the given event set into the event loop, as if the specified event
+had happened for the specified watcher (which must be a pointer to an
+initialised but not necessarily started event watcher). Obviously you must
+not free the watcher as long as it has pending events.
+
+Stopping the watcher, letting libev invoke it, or calling
+C<ev_clear_pending> will clear the pending event, even if the watcher was
+not started in the first place.
+
+See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
+functions that do not need a watcher.
+
+=back
+
+See also the L</ASSOCIATING CUSTOM DATA WITH A WATCHER> and L</BUILDING YOUR
+OWN COMPOSITE WATCHERS> idioms.
+
+=head2 WATCHER STATES
+
+There are various watcher states mentioned throughout this manual -
+active, pending and so on. In this section these states and the rules to
+transition between them will be described in more detail - and while these
+rules might look complicated, they usually do "the right thing".
+
+=over 4
+
+=item initialised
+
+Before a watcher can be registered with the event loop it has to be
+initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
+C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
+
+In this state it is simply some block of memory that is suitable for
+use in an event loop. It can be moved around, freed, reused etc. at
+will - as long as you either keep the memory contents intact, or call
+C<ev_TYPE_init> again.
+
+=item started/running/active
+
+Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
+property of the event loop, and is actively waiting for events. While in
+this state it cannot be accessed (except in a few documented ways), moved,
+freed or anything else - the only legal thing is to keep a pointer to it,
+and call libev functions on it that are documented to work on active watchers.
+
+=item pending
+
+If a watcher is active and libev determines that an event it is interested
+in has occurred (such as a timer expiring), it will become pending. It will
+stay in this pending state until either it is stopped or its callback is
+about to be invoked, so it is not normally pending inside the watcher
+callback.
+
+The watcher might or might not be active while it is pending (for example,
+an expired non-repeating timer can be pending but no longer active). If it
+is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
+but it is still property of the event loop at this time, so cannot be
+moved, freed or reused. And if it is active the rules described in the
+previous item still apply.
+
+It is also possible to feed an event on a watcher that is not active (e.g.
+via C<ev_feed_event>), in which case it becomes pending without being
+active.
+
+=item stopped
+
+A watcher can be stopped implicitly by libev (in which case it might still
+be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
+latter will clear any pending state the watcher might be in, regardless
+of whether it was active or not, so stopping a watcher explicitly before
+freeing it is often a good idea.
+
+While stopped (and not pending) the watcher is essentially in the
+initialised state, that is, it can be reused, moved, modified in any way
+you wish (but when you trash the memory block, you need to C<ev_TYPE_init>
+it again).
+
+=back
+
+=head2 WATCHER PRIORITY MODELS
+
+Many event loops support I<watcher priorities>, which are usually small
+integers that influence the ordering of event callback invocation
+between watchers in some way, all else being equal.
+
+In libev, watcher priorities can be set using C<ev_set_priority>. See its
+description for the more technical details such as the actual priority
+range.
+
+There are two common ways how these these priorities are being interpreted
+by event loops:
+
+In the more common lock-out model, higher priorities "lock out" invocation
+of lower priority watchers, which means as long as higher priority
+watchers receive events, lower priority watchers are not being invoked.
+
+The less common only-for-ordering model uses priorities solely to order
+callback invocation within a single event loop iteration: Higher priority
+watchers are invoked before lower priority ones, but they all get invoked
+before polling for new events.
+
+Libev uses the second (only-for-ordering) model for all its watchers
+except for idle watchers (which use the lock-out model).
+
+The rationale behind this is that implementing the lock-out model for
+watchers is not well supported by most kernel interfaces, and most event
+libraries will just poll for the same events again and again as long as
+their callbacks have not been executed, which is very inefficient in the
+common case of one high-priority watcher locking out a mass of lower
+priority ones.
+
+Static (ordering) priorities are most useful when you have two or more
+watchers handling the same resource: a typical usage example is having an
+C<ev_io> watcher to receive data, and an associated C<ev_timer> to handle
+timeouts. Under load, data might be received while the program handles
+other jobs, but since timers normally get invoked first, the timeout
+handler will be executed before checking for data. In that case, giving
+the timer a lower priority than the I/O watcher ensures that I/O will be
+handled first even under adverse conditions (which is usually, but not
+always, what you want).
+
+Since idle watchers use the "lock-out" model, meaning that idle watchers
+will only be executed when no same or higher priority watchers have
+received events, they can be used to implement the "lock-out" model when
+required.
+
+For example, to emulate how many other event libraries handle priorities,
+you can associate an C<ev_idle> watcher to each such watcher, and in
+the normal watcher callback, you just start the idle watcher. The real
+processing is done in the idle watcher callback. This causes libev to
+continuously poll and process kernel event data for the watcher, but when
+the lock-out case is known to be rare (which in turn is rare :), this is
+workable.
+
+Usually, however, the lock-out model implemented that way will perform
+miserably under the type of load it was designed to handle. In that case,
+it might be preferable to stop the real watcher before starting the
+idle watcher, so the kernel will not have to process the event in case
+the actual processing will be delayed for considerable time.
+
+Here is an example of an I/O watcher that should run at a strictly lower
+priority than the default, and which should only process data when no
+other events are pending:
+
+ ev_idle idle; // actual processing watcher
+ ev_io io; // actual event watcher
+
+ static void
+ io_cb (EV_P_ ev_io *w, int revents)
+ {
+ // stop the I/O watcher, we received the event, but
+ // are not yet ready to handle it.
+ ev_io_stop (EV_A_ w);
+
+ // start the idle watcher to handle the actual event.
+ // it will not be executed as long as other watchers
+ // with the default priority are receiving events.
+ ev_idle_start (EV_A_ &idle);
+ }
+
+ static void
+ idle_cb (EV_P_ ev_idle *w, int revents)
+ {
+ // actual processing
+ read (STDIN_FILENO, ...);
+
+ // have to start the I/O watcher again, as
+ // we have handled the event
+ ev_io_start (EV_P_ &io);
+ }
+
+ // initialisation
+ ev_idle_init (&idle, idle_cb);
+ ev_io_init (&io, io_cb, STDIN_FILENO, EV_READ);
+ ev_io_start (EV_DEFAULT_ &io);
+
+In the "real" world, it might also be beneficial to start a timer, so that
+low-priority connections can not be locked out forever under load. This
+enables your program to keep a lower latency for important connections
+during short periods of high load, while not completely locking out less
+important ones.
+
+
+=head1 WATCHER TYPES
+
+This section describes each watcher in detail, but will not repeat
+information given in the last section. Any initialisation/set macros,
+functions and members specific to the watcher type are explained.
+
+Most members are additionally marked with either I<[read-only]>, meaning
+that, while the watcher is active, you can look at the member and expect
+some sensible content, but you must not modify it (you can modify it while
+the watcher is stopped to your hearts content), or I<[read-write]>, which
+means you can expect it to have some sensible content while the watcher is
+active, but you can also modify it (within the same thread as the event
+loop, i.e. without creating data races). Modifying it may not do something
+sensible or take immediate effect (or do anything at all), but libev will
+not crash or malfunction in any way.
+
+In any case, the documentation for each member will explain what the
+effects are, and if there are any additional access restrictions.
+
+=head2 C<ev_io> - is this file descriptor readable or writable?
+
+I/O watchers check whether a file descriptor is readable or writable
+in each iteration of the event loop, or, more precisely, when reading
+would not block the process and writing would at least be able to write
+some data. This behaviour is called level-triggering because you keep
+receiving events as long as the condition persists. Remember you can stop
+the watcher if you don't want to act on the event and neither want to
+receive future events.
+
+In general you can register as many read and/or write event watchers per
+fd as you want (as long as you don't confuse yourself). Setting all file
+descriptors to non-blocking mode is also usually a good idea (but not
+required if you know what you are doing).
+
+Another thing you have to watch out for is that it is quite easy to
+receive "spurious" readiness notifications, that is, your callback might
+be called with C<EV_READ> but a subsequent C<read>(2) will actually block
+because there is no data. It is very easy to get into this situation even
+with a relatively standard program structure. Thus it is best to always
+use non-blocking I/O: An extra C<read>(2) returning C<EAGAIN> is far
+preferable to a program hanging until some data arrives.
+
+If you cannot run the fd in non-blocking mode (for example you should
+not play around with an Xlib connection), then you have to separately
+re-test whether a file descriptor is really ready with a known-to-be good
+interface such as poll (fortunately in the case of Xlib, it already does
+this on its own, so its quite safe to use). Some people additionally
+use C<SIGALRM> and an interval timer, just to be sure you won't block
+indefinitely.
+
+But really, best use non-blocking mode.
+
+=head3 The special problem of disappearing file descriptors
+
+Some backends (e.g. kqueue, epoll, linuxaio) need to be told about closing
+a file descriptor (either due to calling C<close> explicitly or any other
+means, such as C<dup2>). The reason is that you register interest in some
+file descriptor, but when it goes away, the operating system will silently
+drop this interest. If another file descriptor with the same number then
+is registered with libev, there is no efficient way to see that this is,
+in fact, a different file descriptor.
+
+To avoid having to explicitly tell libev about such cases, libev follows
+the following policy: Each time C<ev_io_set> is being called, libev
+will assume that this is potentially a new file descriptor, otherwise
+it is assumed that the file descriptor stays the same. That means that
+you I<have> to call C<ev_io_set> (or C<ev_io_init>) when you change the
+descriptor even if the file descriptor number itself did not change.
+
+This is how one would do it normally anyway, the important point is that
+the libev application should not optimise around libev but should leave
+optimisations to libev.
+
+=head3 The special problem of dup'ed file descriptors
+
+Some backends (e.g. epoll), cannot register events for file descriptors,
+but only events for the underlying file descriptions. That means when you
+have C<dup ()>'ed file descriptors or weirder constellations, and register
+events for them, only one file descriptor might actually receive events.
+
+There is no workaround possible except not registering events
+for potentially C<dup ()>'ed file descriptors, or to resort to
+C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>.
+
+=head3 The special problem of files
+
+Many people try to use C<select> (or libev) on file descriptors
+representing files, and expect it to become ready when their program
+doesn't block on disk accesses (which can take a long time on their own).
+
+However, this cannot ever work in the "expected" way - you get a readiness
+notification as soon as the kernel knows whether and how much data is
+there, and in the case of open files, that's always the case, so you
+always get a readiness notification instantly, and your read (or possibly
+write) will still block on the disk I/O.
+
+Another way to view it is that in the case of sockets, pipes, character
+devices and so on, there is another party (the sender) that delivers data
+on its own, but in the case of files, there is no such thing: the disk
+will not send data on its own, simply because it doesn't know what you
+wish to read - you would first have to request some data.
+
+Since files are typically not-so-well supported by advanced notification
+mechanism, libev tries hard to emulate POSIX behaviour with respect
+to files, even though you should not use it. The reason for this is
+convenience: sometimes you want to watch STDIN or STDOUT, which is
+usually a tty, often a pipe, but also sometimes files or special devices
+(for example, C<epoll> on Linux works with F</dev/random> but not with
+F</dev/urandom>), and even though the file might better be served with
+asynchronous I/O instead of with non-blocking I/O, it is still useful when
+it "just works" instead of freezing.
+
+So avoid file descriptors pointing to files when you know it (e.g. use
+libeio), but use them when it is convenient, e.g. for STDIN/STDOUT, or
+when you rarely read from a file instead of from a socket, and want to
+reuse the same code path.
+
+=head3 The special problem of fork
+
+Some backends (epoll, kqueue, linuxaio, iouring) do not support C<fork ()>
+at all or exhibit useless behaviour. Libev fully supports fork, but needs
+to be told about it in the child if you want to continue to use it in the
+child.
+
+To support fork in your child processes, you have to call C<ev_loop_fork
+()> after a fork in the child, enable C<EVFLAG_FORKCHECK>, or resort to
+C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>.
+
+=head3 The special problem of SIGPIPE
+
+While not really specific to libev, it is easy to forget about C<SIGPIPE>:
+when writing to a pipe whose other end has been closed, your program gets
+sent a SIGPIPE, which, by default, aborts your program. For most programs
+this is sensible behaviour, for daemons, this is usually undesirable.
+
+So when you encounter spurious, unexplained daemon exits, make sure you
+ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
+somewhere, as that would have given you a big clue).
+
+=head3 The special problem of accept()ing when you can't
+
+Many implementations of the POSIX C<accept> function (for example,
+found in post-2004 Linux) have the peculiar behaviour of not removing a
+connection from the pending queue in all error cases.
+
+For example, larger servers often run out of file descriptors (because
+of resource limits), causing C<accept> to fail with C<ENFILE> but not
+rejecting the connection, leading to libev signalling readiness on
+the next iteration again (the connection still exists after all), and
+typically causing the program to loop at 100% CPU usage.
+
+Unfortunately, the set of errors that cause this issue differs between
+operating systems, there is usually little the app can do to remedy the
+situation, and no known thread-safe method of removing the connection to
+cope with overload is known (to me).
+
+One of the easiest ways to handle this situation is to just ignore it
+- when the program encounters an overload, it will just loop until the
+situation is over. While this is a form of busy waiting, no OS offers an
+event-based way to handle this situation, so it's the best one can do.
+
+A better way to handle the situation is to log any errors other than
+C<EAGAIN> and C<EWOULDBLOCK>, making sure not to flood the log with such
+messages, and continue as usual, which at least gives the user an idea of
+what could be wrong ("raise the ulimit!"). For extra points one could stop
+the C<ev_io> watcher on the listening fd "for a while", which reduces CPU
+usage.
+
+If your program is single-threaded, then you could also keep a dummy file
+descriptor for overload situations (e.g. by opening F</dev/null>), and
+when you run into C<ENFILE> or C<EMFILE>, close it, run C<accept>,
+close that fd, and create a new dummy fd. This will gracefully refuse
+clients under typical overload conditions.
+
+The last way to handle it is to simply log the error and C<exit>, as
+is often done with C<malloc> failures, but this results in an easy
+opportunity for a DoS attack.
+
+=head3 Watcher-Specific Functions
+
+=over 4
+
+=item ev_io_init (ev_io *, callback, int fd, int events)
+
+=item ev_io_set (ev_io *, int fd, int events)
+
+Configures an C<ev_io> watcher. The C<fd> is the file descriptor to
+receive events for and C<events> is either C<EV_READ>, C<EV_WRITE>, both
+C<EV_READ | EV_WRITE> or C<0>, to express the desire to receive the given
+events.
+
+Note that setting the C<events> to C<0> and starting the watcher is
+supported, but not specially optimized - if your program sometimes happens
+to generate this combination this is fine, but if it is easy to avoid
+starting an io watcher watching for no events you should do so.
+
+=item ev_io_modify (ev_io *, int events)
+
+Similar to C<ev_io_set>, but only changes the requested events. Using this
+might be faster with some backends, as libev can assume that the C<fd>
+still refers to the same underlying file description, something it cannot
+do when using C<ev_io_set>.
+
+=item int fd [no-modify]
+
+The file descriptor being watched. While it can be read at any time, you
+must not modify this member even when the watcher is stopped - always use
+C<ev_io_set> for that.
+
+=item int events [no-modify]
+
+The set of events the fd is being watched for, among other flags. Remember
+that this is a bit set - to test for C<EV_READ>, use C<< w->events &
+EV_READ >>, and similarly for C<EV_WRITE>.
+
+As with C<fd>, you must not modify this member even when the watcher is
+stopped, always use C<ev_io_set> or C<ev_io_modify> for that.
+
+=back
+
+=head3 Examples
+
+Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well
+readable, but only once. Since it is likely line-buffered, you could
+attempt to read a whole line in the callback.
+
+ static void
+ stdin_readable_cb (struct ev_loop *loop, ev_io *w, int revents)
+ {
+ ev_io_stop (loop, w);
+ .. read from stdin here (or from w->fd) and handle any I/O errors
+ }
+
+ ...
+ struct ev_loop *loop = ev_default_init (0);
+ ev_io stdin_readable;
+ ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
+ ev_io_start (loop, &stdin_readable);
+ ev_run (loop, 0);
+
+
+=head2 C<ev_timer> - relative and optionally repeating timeouts
+
+Timer watchers are simple relative timers that generate an event after a
+given time, and optionally repeating in regular intervals after that.
+
+The timers are based on real time, that is, if you register an event that
+times out after an hour and you reset your system clock to January last
+year, it will still time out after (roughly) one hour. "Roughly" because
+detecting time jumps is hard, and some inaccuracies are unavoidable (the
+monotonic clock option helps a lot here).
+
+The callback is guaranteed to be invoked only I<after> its timeout has
+passed (not I<at>, so on systems with very low-resolution clocks this
+might introduce a small delay, see "the special problem of being too
+early", below). If multiple timers become ready during the same loop
+iteration then the ones with earlier time-out values are invoked before
+ones of the same priority with later time-out values (but this is no
+longer true when a callback calls C<ev_run> recursively).
+
+=head3 Be smart about timeouts
+
+Many real-world problems involve some kind of timeout, usually for error
+recovery. A typical example is an HTTP request - if the other side hangs,
+you want to raise some error after a while.
+
+What follows are some ways to handle this problem, from obvious and
+inefficient to smart and efficient.
+
+In the following, a 60 second activity timeout is assumed - a timeout that
+gets reset to 60 seconds each time there is activity (e.g. each time some
+data or other life sign was received).
+
+=over 4
+
+=item 1. Use a timer and stop, reinitialise and start it on activity.
+
+This is the most obvious, but not the most simple way: In the beginning,
+start the watcher:
+
+ ev_timer_init (timer, callback, 60., 0.);
+ ev_timer_start (loop, timer);
+
+Then, each time there is some activity, C<ev_timer_stop> it, initialise it
+and start it again:
+
+ ev_timer_stop (loop, timer);
+ ev_timer_set (timer, 60., 0.);
+ ev_timer_start (loop, timer);
+
+This is relatively simple to implement, but means that each time there is
+some activity, libev will first have to remove the timer from its internal
+data structure and then add it again. Libev tries to be fast, but it's
+still not a constant-time operation.
+
+=item 2. Use a timer and re-start it with C<ev_timer_again> inactivity.
+
+This is the easiest way, and involves using C<ev_timer_again> instead of
+C<ev_timer_start>.
+
+To implement this, configure an C<ev_timer> with a C<repeat> value
+of C<60> and then call C<ev_timer_again> at start and each time you
+successfully read or write some data. If you go into an idle state where
+you do not expect data to travel on the socket, you can C<ev_timer_stop>
+the timer, and C<ev_timer_again> will automatically restart it if need be.
+
+That means you can ignore both the C<ev_timer_start> function and the
+C<after> argument to C<ev_timer_set>, and only ever use the C<repeat>
+member and C<ev_timer_again>.
+
+At start:
+
+ ev_init (timer, callback);
+ timer->repeat = 60.;
+ ev_timer_again (loop, timer);
+
+Each time there is some activity:
+
+ ev_timer_again (loop, timer);
+
+It is even possible to change the time-out on the fly, regardless of
+whether the watcher is active or not:
+
+ timer->repeat = 30.;
+ ev_timer_again (loop, timer);
+
+This is slightly more efficient then stopping/starting the timer each time
+you want to modify its timeout value, as libev does not have to completely
+remove and re-insert the timer from/into its internal data structure.
+
+It is, however, even simpler than the "obvious" way to do it.
+
+=item 3. Let the timer time out, but then re-arm it as required.
+
+This method is more tricky, but usually most efficient: Most timeouts are
+relatively long compared to the intervals between other activity - in
+our example, within 60 seconds, there are usually many I/O events with
+associated activity resets.
+
+In this case, it would be more efficient to leave the C<ev_timer> alone,
+but remember the time of last activity, and check for a real timeout only
+within the callback:
+
+ ev_tstamp timeout = 60.;
+ ev_tstamp last_activity; // time of last activity
+ ev_timer timer;
+
+ static void
+ callback (EV_P_ ev_timer *w, int revents)
+ {
+ // calculate when the timeout would happen
+ ev_tstamp after = last_activity - ev_now (EV_A) + timeout;
+
+ // if negative, it means we the timeout already occurred
+ if (after < 0.)
+ {
+ // timeout occurred, take action
+ }
+ else
+ {
+ // callback was invoked, but there was some recent
+ // activity. simply restart the timer to time out
+ // after "after" seconds, which is the earliest time
+ // the timeout can occur.
+ ev_timer_set (w, after, 0.);
+ ev_timer_start (EV_A_ w);
+ }
+ }
+
+To summarise the callback: first calculate in how many seconds the
+timeout will occur (by calculating the absolute time when it would occur,
+C<last_activity + timeout>, and subtracting the current time, C<ev_now
+(EV_A)> from that).
+
+If this value is negative, then we are already past the timeout, i.e. we
+timed out, and need to do whatever is needed in this case.
+
+Otherwise, we now the earliest time at which the timeout would trigger,
+and simply start the timer with this timeout value.
+
+In other words, each time the callback is invoked it will check whether
+the timeout occurred. If not, it will simply reschedule itself to check
+again at the earliest time it could time out. Rinse. Repeat.
+
+This scheme causes more callback invocations (about one every 60 seconds
+minus half the average time between activity), but virtually no calls to
+libev to change the timeout.
+
+To start the machinery, simply initialise the watcher and set
+C<last_activity> to the current time (meaning there was some activity just
+now), then call the callback, which will "do the right thing" and start
+the timer:
+
+ last_activity = ev_now (EV_A);
+ ev_init (&timer, callback);
+ callback (EV_A_ &timer, 0);
+
+When there is some activity, simply store the current time in
+C<last_activity>, no libev calls at all:
+
+ if (activity detected)
+ last_activity = ev_now (EV_A);
+
+When your timeout value changes, then the timeout can be changed by simply
+providing a new value, stopping the timer and calling the callback, which
+will again do the right thing (for example, time out immediately :).
+
+ timeout = new_value;
+ ev_timer_stop (EV_A_ &timer);
+ callback (EV_A_ &timer, 0);
+
+This technique is slightly more complex, but in most cases where the
+time-out is unlikely to be triggered, much more efficient.
+
+=item 4. Wee, just use a double-linked list for your timeouts.
+
+If there is not one request, but many thousands (millions...), all
+employing some kind of timeout with the same timeout value, then one can
+do even better:
+
+When starting the timeout, calculate the timeout value and put the timeout
+at the I<end> of the list.
+
+Then use an C<ev_timer> to fire when the timeout at the I<beginning> of
+the list is expected to fire (for example, using the technique #3).
+
+When there is some activity, remove the timer from the list, recalculate
+the timeout, append it to the end of the list again, and make sure to
+update the C<ev_timer> if it was taken from the beginning of the list.
+
+This way, one can manage an unlimited number of timeouts in O(1) time for
+starting, stopping and updating the timers, at the expense of a major
+complication, and having to use a constant timeout. The constant timeout
+ensures that the list stays sorted.
+
+=back
+
+So which method the best?
+
+Method #2 is a simple no-brain-required solution that is adequate in most
+situations. Method #3 requires a bit more thinking, but handles many cases
+better, and isn't very complicated either. In most case, choosing either
+one is fine, with #3 being better in typical situations.
+
+Method #1 is almost always a bad idea, and buys you nothing. Method #4 is
+rather complicated, but extremely efficient, something that really pays
+off after the first million or so of active timers, i.e. it's usually
+overkill :)
+
+=head3 The special problem of being too early
+
+If you ask a timer to call your callback after three seconds, then
+you expect it to be invoked after three seconds - but of course, this
+cannot be guaranteed to infinite precision. Less obviously, it cannot be
+guaranteed to any precision by libev - imagine somebody suspending the
+process with a STOP signal for a few hours for example.
+
+So, libev tries to invoke your callback as soon as possible I<after> the
+delay has occurred, but cannot guarantee this.
+
+A less obvious failure mode is calling your callback too early: many event
+loops compare timestamps with a "elapsed delay >= requested delay", but
+this can cause your callback to be invoked much earlier than you would
+expect.
+
+To see why, imagine a system with a clock that only offers full second
+resolution (think windows if you can't come up with a broken enough OS
+yourself). If you schedule a one-second timer at the time 500.9, then the
+event loop will schedule your timeout to elapse at a system time of 500
+(500.9 truncated to the resolution) + 1, or 501.
+
+If an event library looks at the timeout 0.1s later, it will see "501 >=
+501" and invoke the callback 0.1s after it was started, even though a
+one-second delay was requested - this is being "too early", despite best
+intentions.
+
+This is the reason why libev will never invoke the callback if the elapsed
+delay equals the requested delay, but only when the elapsed delay is
+larger than the requested delay. In the example above, libev would only invoke
+the callback at system time 502, or 1.1s after the timer was started.
+
+So, while libev cannot guarantee that your callback will be invoked
+exactly when requested, it I<can> and I<does> guarantee that the requested
+delay has actually elapsed, or in other words, it always errs on the "too
+late" side of things.
+
+=head3 The special problem of time updates
+
+Establishing the current time is a costly operation (it usually takes
+at least one system call): EV therefore updates its idea of the current
+time only before and after C<ev_run> collects new events, which causes a
+growing difference between C<ev_now ()> and C<ev_time ()> when handling
+lots of events in one iteration.
+
+The relative timeouts are calculated relative to the C<ev_now ()>
+time. This is usually the right thing as this timestamp refers to the time
+of the event triggering whatever timeout you are modifying/starting. If
+you suspect event processing to be delayed and you I<need> to base the
+timeout on the current time, use something like the following to adjust
+for it:
+
+ ev_timer_set (&timer, after + (ev_time () - ev_now ()), 0.);
+
+If the event loop is suspended for a long time, you can also force an
+update of the time returned by C<ev_now ()> by calling C<ev_now_update
+()>, although that will push the event time of all outstanding events
+further into the future.
+
+=head3 The special problem of unsynchronised clocks
+
+Modern systems have a variety of clocks - libev itself uses the normal
+"wall clock" clock and, if available, the monotonic clock (to avoid time
+jumps).
+
+Neither of these clocks is synchronised with each other or any other clock
+on the system, so C<ev_time ()> might return a considerably different time
+than C<gettimeofday ()> or C<time ()>. On a GNU/Linux system, for example,
+a call to C<gettimeofday> might return a second count that is one higher
+than a directly following call to C<time>.
+
+The moral of this is to only compare libev-related timestamps with
+C<ev_time ()> and C<ev_now ()>, at least if you want better precision than
+a second or so.
+
+One more problem arises due to this lack of synchronisation: if libev uses
+the system monotonic clock and you compare timestamps from C<ev_time>
+or C<ev_now> from when you started your timer and when your callback is
+invoked, you will find that sometimes the callback is a bit "early".
+
+This is because C<ev_timer>s work in real time, not wall clock time, so
+libev makes sure your callback is not invoked before the delay happened,
+I<measured according to the real time>, not the system clock.
+
+If your timeouts are based on a physical timescale (e.g. "time out this
+connection after 100 seconds") then this shouldn't bother you as it is
+exactly the right behaviour.
+
+If you want to compare wall clock/system timestamps to your timers, then
+you need to use C<ev_periodic>s, as these are based on the wall clock
+time, where your comparisons will always generate correct results.
+
+=head3 The special problems of suspended animation
+
+When you leave the server world it is quite customary to hit machines that
+can suspend/hibernate - what happens to the clocks during such a suspend?
+
+Some quick tests made with a Linux 2.6.28 indicate that a suspend freezes
+all processes, while the clocks (C<times>, C<CLOCK_MONOTONIC>) continue
+to run until the system is suspended, but they will not advance while the
+system is suspended. That means, on resume, it will be as if the program
+was frozen for a few seconds, but the suspend time will not be counted
+towards C<ev_timer> when a monotonic clock source is used. The real time
+clock advanced as expected, but if it is used as sole clocksource, then a
+long suspend would be detected as a time jump by libev, and timers would
+be adjusted accordingly.
+
+I would not be surprised to see different behaviour in different between
+operating systems, OS versions or even different hardware.
+
+The other form of suspend (job control, or sending a SIGSTOP) will see a
+time jump in the monotonic clocks and the realtime clock. If the program
+is suspended for a very long time, and monotonic clock sources are in use,
+then you can expect C<ev_timer>s to expire as the full suspension time
+will be counted towards the timers. When no monotonic clock source is in
+use, then libev will again assume a timejump and adjust accordingly.
+
+It might be beneficial for this latter case to call C<ev_suspend>
+and C<ev_resume> in code that handles C<SIGTSTP>, to at least get
+deterministic behaviour in this case (you can do nothing against
+C<SIGSTOP>).
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)
+
+=item ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)
+
+Configure the timer to trigger after C<after> seconds (fractional and
+negative values are supported). If C<repeat> is C<0.>, then it will
+automatically be stopped once the timeout is reached. If it is positive,
+then the timer will automatically be configured to trigger again C<repeat>
+seconds later, again, and again, until stopped manually.
+
+The timer itself will do a best-effort at avoiding drift, that is, if
+you configure a timer to trigger every 10 seconds, then it will normally
+trigger at exactly 10 second intervals. If, however, your program cannot
+keep up with the timer (because it takes longer than those 10 seconds to
+do stuff) the timer will not fire more than once per event loop iteration.
+
+=item ev_timer_again (loop, ev_timer *)
+
+This will act as if the timer timed out, and restarts it again if it is
+repeating. It basically works like calling C<ev_timer_stop>, updating the
+timeout to the C<repeat> value and calling C<ev_timer_start>.
+
+The exact semantics are as in the following rules, all of which will be
+applied to the watcher:
+
+=over 4
+
+=item If the timer is pending, the pending status is always cleared.
+
+=item If the timer is started but non-repeating, stop it (as if it timed
+out, without invoking it).
+
+=item If the timer is repeating, make the C<repeat> value the new timeout
+and start the timer, if necessary.
+
+=back
+
+This sounds a bit complicated, see L</Be smart about timeouts>, above, for a
+usage example.
+
+=item ev_tstamp ev_timer_remaining (loop, ev_timer *)
+
+Returns the remaining time until a timer fires. If the timer is active,
+then this time is relative to the current event loop time, otherwise it's
+the timeout value currently configured.
+
+That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns
+C<5>. When the timer is started and one second passes, C<ev_timer_remaining>
+will return C<4>. When the timer expires and is restarted, it will return
+roughly C<7> (likely slightly less as callback invocation takes some time,
+too), and so on.
+
+=item ev_tstamp repeat [read-write]
+
+The current C<repeat> value. Will be used each time the watcher times out
+or C<ev_timer_again> is called, and determines the next timeout (if any),
+which is also when any modifications are taken into account.
+
+=back
+
+=head3 Examples
+
+Example: Create a timer that fires after 60 seconds.
+
+ static void
+ one_minute_cb (struct ev_loop *loop, ev_timer *w, int revents)
+ {
+ .. one minute over, w is actually stopped right here
+ }
+
+ ev_timer mytimer;
+ ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
+ ev_timer_start (loop, &mytimer);
+
+Example: Create a timeout timer that times out after 10 seconds of
+inactivity.
+
+ static void
+ timeout_cb (struct ev_loop *loop, ev_timer *w, int revents)
+ {
+ .. ten seconds without any activity
+ }
+
+ ev_timer mytimer;
+ ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
+ ev_timer_again (&mytimer); /* start timer */
+ ev_run (loop, 0);
+
+ // and in some piece of code that gets executed on any "activity":
+ // reset the timeout to start ticking again at 10 seconds
+ ev_timer_again (&mytimer);
+
+
+=head2 C<ev_periodic> - to cron or not to cron?
+
+Periodic watchers are also timers of a kind, but they are very versatile
+(and unfortunately a bit complex).
+
+Unlike C<ev_timer>, periodic watchers are not based on real time (or
+relative time, the physical time that passes) but on wall clock time
+(absolute time, the thing you can read on your calendar or clock). The
+difference is that wall clock time can run faster or slower than real
+time, and time jumps are not uncommon (e.g. when you adjust your
+wrist-watch).
+
+You can tell a periodic watcher to trigger after some specific point
+in time: for example, if you tell a periodic watcher to trigger "in 10
+seconds" (by specifying e.g. C<ev_now () + 10.>, that is, an absolute time
+not a delay) and then reset your system clock to January of the previous
+year, then it will take a year or more to trigger the event (unlike an
+C<ev_timer>, which would still trigger roughly 10 seconds after starting
+it, as it uses a relative timeout).
+
+C<ev_periodic> watchers can also be used to implement vastly more complex
+timers, such as triggering an event on each "midnight, local time", or
+other complicated rules. This cannot easily be done with C<ev_timer>
+watchers, as those cannot react to time jumps.
+
+As with timers, the callback is guaranteed to be invoked only when the
+point in time where it is supposed to trigger has passed. If multiple
+timers become ready during the same loop iteration then the ones with
+earlier time-out values are invoked before ones with later time-out values
+(but this is no longer true when a callback calls C<ev_run> recursively).
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)
+
+=item ev_periodic_set (ev_periodic *, ev_tstamp offset, ev_tstamp interval, reschedule_cb)
+
+Lots of arguments, let's sort it out... There are basically three modes of
+operation, and we will explain them from simplest to most complex:
+
+=over 4
+
+=item * absolute timer (offset = absolute time, interval = 0, reschedule_cb = 0)
+
+In this configuration the watcher triggers an event after the wall clock
+time C<offset> has passed. It will not repeat and will not adjust when a
+time jump occurs, that is, if it is to be run at January 1st 2011 then it
+will be stopped and invoked when the system clock reaches or surpasses
+this point in time.
+
+=item * repeating interval timer (offset = offset within interval, interval > 0, reschedule_cb = 0)
+
+In this mode the watcher will always be scheduled to time out at the next
+C<offset + N * interval> time (for some integer N, which can also be
+negative) and then repeat, regardless of any time jumps. The C<offset>
+argument is merely an offset into the C<interval> periods.
+
+This can be used to create timers that do not drift with respect to the
+system clock, for example, here is an C<ev_periodic> that triggers each
+hour, on the hour (with respect to UTC):
+
+ ev_periodic_set (&periodic, 0., 3600., 0);
+
+This doesn't mean there will always be 3600 seconds in between triggers,
+but only that the callback will be called when the system time shows a
+full hour (UTC), or more correctly, when the system time is evenly divisible
+by 3600.
+
+Another way to think about it (for the mathematically inclined) is that
+C<ev_periodic> will try to run the callback in this mode at the next possible
+time where C<time = offset (mod interval)>, regardless of any time jumps.
+
+The C<interval> I<MUST> be positive, and for numerical stability, the
+interval value should be higher than C<1/8192> (which is around 100
+microseconds) and C<offset> should be higher than C<0> and should have
+at most a similar magnitude as the current time (say, within a factor of
+ten). Typical values for offset are, in fact, C<0> or something between
+C<0> and C<interval>, which is also the recommended range.
+
+Note also that there is an upper limit to how often a timer can fire (CPU
+speed for example), so if C<interval> is very small then timing stability
+will of course deteriorate. Libev itself tries to be exact to be about one
+millisecond (if the OS supports it and the machine is fast enough).
+
+=item * manual reschedule mode (offset ignored, interval ignored, reschedule_cb = callback)
+
+In this mode the values for C<interval> and C<offset> are both being
+ignored. Instead, each time the periodic watcher gets scheduled, the
+reschedule callback will be called with the watcher as first, and the
+current time as second argument.
+
+NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, ever,
+or make ANY other event loop modifications whatsoever, unless explicitly
+allowed by documentation here>.
+
+If you need to stop it, return C<now + 1e30> (or so, fudge fudge) and stop
+it afterwards (e.g. by starting an C<ev_prepare> watcher, which is the
+only event loop modification you are allowed to do).
+
+The callback prototype is C<ev_tstamp (*reschedule_cb)(ev_periodic
+*w, ev_tstamp now)>, e.g.:
+
+ static ev_tstamp
+ my_rescheduler (ev_periodic *w, ev_tstamp now)
+ {
+ return now + 60.;
+ }
+
+It must return the next time to trigger, based on the passed time value
+(that is, the lowest time value larger than to the second argument). It
+will usually be called just before the callback will be triggered, but
+might be called at other times, too.
+
+NOTE: I<< This callback must always return a time that is higher than or
+equal to the passed C<now> value >>.
+
+This can be used to create very complex timers, such as a timer that
+triggers on "next midnight, local time". To do this, you would calculate
+the next midnight after C<now> and return the timestamp value for
+this. Here is a (completely untested, no error checking) example on how to
+do this:
+
+ #include <time.h>
+
+ static ev_tstamp
+ my_rescheduler (ev_periodic *w, ev_tstamp now)
+ {
+ time_t tnow = (time_t)now;
+ struct tm tm;
+ localtime_r (&tnow, &tm);
+
+ tm.tm_sec = tm.tm_min = tm.tm_hour = 0; // midnight current day
+ ++tm.tm_mday; // midnight next day
+
+ return mktime (&tm);
+ }
+
+Note: this code might run into trouble on days that have more then two
+midnights (beginning and end).
+
+=back
+
+=item ev_periodic_again (loop, ev_periodic *)
+
+Simply stops and restarts the periodic watcher again. This is only useful
+when you changed some parameters or the reschedule callback would return
+a different time than the last time it was called (e.g. in a crond like
+program when the crontabs have changed).
+
+=item ev_tstamp ev_periodic_at (ev_periodic *)
+
+When active, returns the absolute time that the watcher is supposed
+to trigger next. This is not the same as the C<offset> argument to
+C<ev_periodic_set>, but indeed works even in interval and manual
+rescheduling modes.
+
+=item ev_tstamp offset [read-write]
+
+When repeating, this contains the offset value, otherwise this is the
+absolute point in time (the C<offset> value passed to C<ev_periodic_set>,
+although libev might modify this value for better numerical stability).
+
+Can be modified any time, but changes only take effect when the periodic
+timer fires or C<ev_periodic_again> is being called.
+
+=item ev_tstamp interval [read-write]
+
+The current interval value. Can be modified any time, but changes only
+take effect when the periodic timer fires or C<ev_periodic_again> is being
+called.
+
+=item ev_tstamp (*reschedule_cb)(ev_periodic *w, ev_tstamp now) [read-write]
+
+The current reschedule callback, or C<0>, if this functionality is
+switched off. Can be changed any time, but changes only take effect when
+the periodic timer fires or C<ev_periodic_again> is being called.
+
+=back
+
+=head3 Examples
+
+Example: Call a callback every hour, or, more precisely, whenever the
+system time is divisible by 3600. The callback invocation times have
+potentially a lot of jitter, but good long-term stability.
+
+ static void
+ clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
+ {
+ ... its now a full hour (UTC, or TAI or whatever your clock follows)
+ }
+
+ ev_periodic hourly_tick;
+ ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
+ ev_periodic_start (loop, &hourly_tick);
+
+Example: The same as above, but use a reschedule callback to do it:
+
+ #include <math.h>
+
+ static ev_tstamp
+ my_scheduler_cb (ev_periodic *w, ev_tstamp now)
+ {
+ return now + (3600. - fmod (now, 3600.));
+ }
+
+ ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
+
+Example: Call a callback every hour, starting now:
+
+ ev_periodic hourly_tick;
+ ev_periodic_init (&hourly_tick, clock_cb,
+ fmod (ev_now (loop), 3600.), 3600., 0);
+ ev_periodic_start (loop, &hourly_tick);
+
+
+=head2 C<ev_signal> - signal me when a signal gets signalled!
+
+Signal watchers will trigger an event when the process receives a specific
+signal one or more times. Even though signals are very asynchronous, libev
+will try its best to deliver signals synchronously, i.e. as part of the
+normal event processing, like any other event.
+
+If you want signals to be delivered truly asynchronously, just use
+C<sigaction> as you would do without libev and forget about sharing
+the signal. You can even use C<ev_async> from a signal handler to
+synchronously wake up an event loop.
+
+You can configure as many watchers as you like for the same signal, but
+only within the same loop, i.e. you can watch for C<SIGINT> in your
+default loop and for C<SIGIO> in another loop, but you cannot watch for
+C<SIGINT> in both the default loop and another loop at the same time. At
+the moment, C<SIGCHLD> is permanently tied to the default loop.
+
+Only after the first watcher for a signal is started will libev actually
+register something with the kernel. It thus coexists with your own signal
+handlers as long as you don't register any with libev for the same signal.
+
+If possible and supported, libev will install its handlers with
+C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
+not be unduly interrupted. If you have a problem with system calls getting
+interrupted by signals you can block all signals in an C<ev_check> watcher
+and unblock them in an C<ev_prepare> watcher.
+
+=head3 The special problem of inheritance over fork/execve/pthread_create
+
+Both the signal mask (C<sigprocmask>) and the signal disposition
+(C<sigaction>) are unspecified after starting a signal watcher (and after
+stopping it again), that is, libev might or might not block the signal,
+and might or might not set or restore the installed signal handler (but
+see C<EVFLAG_NOSIGMASK>).
+
+While this does not matter for the signal disposition (libev never
+sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on
+C<execve>), this matters for the signal mask: many programs do not expect
+certain signals to be blocked.
+
+This means that before calling C<exec> (from the child) you should reset
+the signal mask to whatever "default" you expect (all clear is a good
+choice usually).
+
+The simplest way to ensure that the signal mask is reset in the child is
+to install a fork handler with C<pthread_atfork> that resets it. That will
+catch fork calls done by libraries (such as the libc) as well.
+
+In current versions of libev, the signal will not be blocked indefinitely
+unless you use the C<signalfd> API (C<EV_SIGNALFD>). While this reduces
+the window of opportunity for problems, it will not go away, as libev
+I<has> to modify the signal mask, at least temporarily.
+
+So I can't stress this enough: I<If you do not reset your signal mask when
+you expect it to be empty, you have a race condition in your code>. This
+is not a libev-specific thing, this is true for most event libraries.
+
+=head3 The special problem of threads signal handling
+
+POSIX threads has problematic signal handling semantics, specifically,
+a lot of functionality (sigfd, sigwait etc.) only really works if all
+threads in a process block signals, which is hard to achieve.
+
+When you want to use sigwait (or mix libev signal handling with your own
+for the same signals), you can tackle this problem by globally blocking
+all signals before creating any threads (or creating them with a fully set
+sigprocmask) and also specifying the C<EVFLAG_NOSIGMASK> when creating
+loops. Then designate one thread as "signal receiver thread" which handles
+these signals. You can pass on any signals that libev might be interested
+in by calling C<ev_feed_signal>.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_signal_init (ev_signal *, callback, int signum)
+
+=item ev_signal_set (ev_signal *, int signum)
+
+Configures the watcher to trigger on the given signal number (usually one
+of the C<SIGxxx> constants).
+
+=item int signum [read-only]
+
+The signal the watcher watches out for.
+
+=back
+
+=head3 Examples
+
+Example: Try to exit cleanly on SIGINT.
+
+ static void
+ sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
+ {
+ ev_break (loop, EVBREAK_ALL);
+ }
+
+ ev_signal signal_watcher;
+ ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
+ ev_signal_start (loop, &signal_watcher);
+
+
+=head2 C<ev_child> - watch out for process status changes
+
+Child watchers trigger when your process receives a SIGCHLD in response to
+some child status changes (most typically when a child of yours dies or
+exits). It is permissible to install a child watcher I<after> the child
+has been forked (which implies it might have already exited), as long
+as the event loop isn't entered (or is continued from a watcher), i.e.,
+forking and then immediately registering a watcher for the child is fine,
+but forking and registering a watcher a few event loop iterations later or
+in the next callback invocation is not.
+
+Only the default event loop is capable of handling signals, and therefore
+you can only register child watchers in the default event loop.
+
+Due to some design glitches inside libev, child watchers will always be
+handled at maximum priority (their priority is set to C<EV_MAXPRI> by
+libev)
+
+=head3 Process Interaction
+
+Libev grabs C<SIGCHLD> as soon as the default event loop is
+initialised. This is necessary to guarantee proper behaviour even if the
+first child watcher is started after the child exits. The occurrence
+of C<SIGCHLD> is recorded asynchronously, but child reaping is done
+synchronously as part of the event loop processing. Libev always reaps all
+children, even ones not watched.
+
+=head3 Overriding the Built-In Processing
+
+Libev offers no special support for overriding the built-in child
+processing, but if your application collides with libev's default child
+handler, you can override it easily by installing your own handler for
+C<SIGCHLD> after initialising the default loop, and making sure the
+default loop never gets destroyed. You are encouraged, however, to use an
+event-based approach to child reaping and thus use libev's support for
+that, so other libev users can use C<ev_child> watchers freely.
+
+=head3 Stopping the Child Watcher
+
+Currently, the child watcher never gets stopped, even when the
+child terminates, so normally one needs to stop the watcher in the
+callback. Future versions of libev might stop the watcher automatically
+when a child exit is detected (calling C<ev_child_stop> twice is not a
+problem).
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_child_init (ev_child *, callback, int pid, int trace)
+
+=item ev_child_set (ev_child *, int pid, int trace)
+
+Configures the watcher to wait for status changes of process C<pid> (or
+I<any> process if C<pid> is specified as C<0>). The callback can look
+at the C<rstatus> member of the C<ev_child> watcher structure to see
+the status word (use the macros from C<sys/wait.h> and see your systems
+C<waitpid> documentation). The C<rpid> member contains the pid of the
+process causing the status change. C<trace> must be either C<0> (only
+activate the watcher when the process terminates) or C<1> (additionally
+activate the watcher when the process is stopped or continued).
+
+=item int pid [read-only]
+
+The process id this watcher watches out for, or C<0>, meaning any process id.
+
+=item int rpid [read-write]
+
+The process id that detected a status change.
+
+=item int rstatus [read-write]
+
+The process exit/trace status caused by C<rpid> (see your systems
+C<waitpid> and C<sys/wait.h> documentation for details).
+
+=back
+
+=head3 Examples
+
+Example: C<fork()> a new process and install a child handler to wait for
+its completion.
+
+ ev_child cw;
+
+ static void
+ child_cb (EV_P_ ev_child *w, int revents)
+ {
+ ev_child_stop (EV_A_ w);
+ printf ("process %d exited with status %x\n", w->rpid, w->rstatus);
+ }
+
+ pid_t pid = fork ();
+
+ if (pid < 0)
+ // error
+ else if (pid == 0)
+ {
+ // the forked child executes here
+ exit (1);
+ }
+ else
+ {
+ ev_child_init (&cw, child_cb, pid, 0);
+ ev_child_start (EV_DEFAULT_ &cw);
+ }
+
+
+=head2 C<ev_stat> - did the file attributes just change?
+
+This watches a file system path for attribute changes. That is, it calls
+C<stat> on that path in regular intervals (or when the OS says it changed)
+and sees if it changed compared to the last time, invoking the callback
+if it did. Starting the watcher C<stat>'s the file, so only changes that
+happen after the watcher has been started will be reported.
+
+The path does not need to exist: changing from "path exists" to "path does
+not exist" is a status change like any other. The condition "path does not
+exist" (or more correctly "path cannot be stat'ed") is signified by the
+C<st_nlink> field being zero (which is otherwise always forced to be at
+least one) and all the other fields of the stat buffer having unspecified
+contents.
+
+The path I<must not> end in a slash or contain special components such as
+C<.> or C<..>. The path I<should> be absolute: If it is relative and
+your working directory changes, then the behaviour is undefined.
+
+Since there is no portable change notification interface available, the
+portable implementation simply calls C<stat(2)> regularly on the path
+to see if it changed somehow. You can specify a recommended polling
+interval for this case. If you specify a polling interval of C<0> (highly
+recommended!) then a I<suitable, unspecified default> value will be used
+(which you can expect to be around five seconds, although this might
+change dynamically). Libev will also impose a minimum interval which is
+currently around C<0.1>, but that's usually overkill.
+
+This watcher type is not meant for massive numbers of stat watchers,
+as even with OS-supported change notifications, this can be
+resource-intensive.
+
+At the time of this writing, the only OS-specific interface implemented
+is the Linux inotify interface (implementing kqueue support is left as an
+exercise for the reader. Note, however, that the author sees no way of
+implementing C<ev_stat> semantics with kqueue, except as a hint).
+
+=head3 ABI Issues (Largefile Support)
+
+Libev by default (unless the user overrides this) uses the default
+compilation environment, which means that on systems with large file
+support disabled by default, you get the 32 bit version of the stat
+structure. When using the library from programs that change the ABI to
+use 64 bit file offsets the programs will fail. In that case you have to
+compile libev with the same flags to get binary compatibility. This is
+obviously the case with any flags that change the ABI, but the problem is
+most noticeably displayed with ev_stat and large file support.
+
+The solution for this is to lobby your distribution maker to make large
+file interfaces available by default (as e.g. FreeBSD does) and not
+optional. Libev cannot simply switch on large file support because it has
+to exchange stat structures with application programs compiled using the
+default compilation environment.
+
+=head3 Inotify and Kqueue
+
+When C<inotify (7)> support has been compiled into libev and present at
+runtime, it will be used to speed up change detection where possible. The
+inotify descriptor will be created lazily when the first C<ev_stat>
+watcher is being started.
+
+Inotify presence does not change the semantics of C<ev_stat> watchers
+except that changes might be detected earlier, and in some cases, to avoid
+making regular C<stat> calls. Even in the presence of inotify support
+there are many cases where libev has to resort to regular C<stat> polling,
+but as long as kernel 2.6.25 or newer is used (2.6.24 and older have too
+many bugs), the path exists (i.e. stat succeeds), and the path resides on
+a local filesystem (libev currently assumes only ext2/3, jfs, reiserfs and
+xfs are fully working) libev usually gets away without polling.
+
+There is no support for kqueue, as apparently it cannot be used to
+implement this functionality, due to the requirement of having a file
+descriptor open on the object at all times, and detecting renames, unlinks
+etc. is difficult.
+
+=head3 C<stat ()> is a synchronous operation
+
+Libev doesn't normally do any kind of I/O itself, and so is not blocking
+the process. The exception are C<ev_stat> watchers - those call C<stat
+()>, which is a synchronous operation.
+
+For local paths, this usually doesn't matter: unless the system is very
+busy or the intervals between stat's are large, a stat call will be fast,
+as the path data is usually in memory already (except when starting the
+watcher).
+
+For networked file systems, calling C<stat ()> can block an indefinite
+time due to network issues, and even under good conditions, a stat call
+often takes multiple milliseconds.
+
+Therefore, it is best to avoid using C<ev_stat> watchers on networked
+paths, although this is fully supported by libev.
+
+=head3 The special problem of stat time resolution
+
+The C<stat ()> system call only supports full-second resolution portably,
+and even on systems where the resolution is higher, most file systems
+still only support whole seconds.
+
+That means that, if the time is the only thing that changes, you can
+easily miss updates: on the first update, C<ev_stat> detects a change and
+calls your callback, which does something. When there is another update
+within the same second, C<ev_stat> will be unable to detect unless the
+stat data does change in other ways (e.g. file size).
+
+The solution to this is to delay acting on a change for slightly more
+than a second (or till slightly after the next full second boundary), using
+a roughly one-second-delay C<ev_timer> (e.g. C<ev_timer_set (w, 0., 1.02);
+ev_timer_again (loop, w)>).
+
+The C<.02> offset is added to work around small timing inconsistencies
+of some operating systems (where the second counter of the current time
+might be be delayed. One such system is the Linux kernel, where a call to
+C<gettimeofday> might return a timestamp with a full second later than
+a subsequent C<time> call - if the equivalent of C<time ()> is used to
+update file times then there will be a small window where the kernel uses
+the previous second to update file times but libev might already execute
+the timer callback).
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)
+
+=item ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)
+
+Configures the watcher to wait for status changes of the given
+C<path>. The C<interval> is a hint on how quickly a change is expected to
+be detected and should normally be specified as C<0> to let libev choose
+a suitable value. The memory pointed to by C<path> must point to the same
+path for as long as the watcher is active.
+
+The callback will receive an C<EV_STAT> event when a change was detected,
+relative to the attributes at the time the watcher was started (or the
+last change was detected).
+
+=item ev_stat_stat (loop, ev_stat *)
+
+Updates the stat buffer immediately with new values. If you change the
+watched path in your callback, you could call this function to avoid
+detecting this change (while introducing a race condition if you are not
+the only one changing the path). Can also be useful simply to find out the
+new values.
+
+=item ev_statdata attr [read-only]
+
+The most-recently detected attributes of the file. Although the type is
+C<ev_statdata>, this is usually the (or one of the) C<struct stat> types
+suitable for your system, but you can only rely on the POSIX-standardised
+members to be present. If the C<st_nlink> member is C<0>, then there was
+some error while C<stat>ing the file.
+
+=item ev_statdata prev [read-only]
+
+The previous attributes of the file. The callback gets invoked whenever
+C<prev> != C<attr>, or, more precisely, one or more of these members
+differ: C<st_dev>, C<st_ino>, C<st_mode>, C<st_nlink>, C<st_uid>,
+C<st_gid>, C<st_rdev>, C<st_size>, C<st_atime>, C<st_mtime>, C<st_ctime>.
+
+=item ev_tstamp interval [read-only]
+
+The specified interval.
+
+=item const char *path [read-only]
+
+The file system path that is being watched.
+
+=back
+
+=head3 Examples
+
+Example: Watch C</etc/passwd> for attribute changes.
+
+ static void
+ passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)
+ {
+ /* /etc/passwd changed in some way */
+ if (w->attr.st_nlink)
+ {
+ printf ("passwd current size %ld\n", (long)w->attr.st_size);
+ printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);
+ printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);
+ }
+ else
+ /* you shalt not abuse printf for puts */
+ puts ("wow, /etc/passwd is not there, expect problems. "
+ "if this is windows, they already arrived\n");
+ }
+
+ ...
+ ev_stat passwd;
+
+ ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
+ ev_stat_start (loop, &passwd);
+
+Example: Like above, but additionally use a one-second delay so we do not
+miss updates (however, frequent updates will delay processing, too, so
+one might do the work both on C<ev_stat> callback invocation I<and> on
+C<ev_timer> callback invocation).
+
+ static ev_stat passwd;
+ static ev_timer timer;
+
+ static void
+ timer_cb (EV_P_ ev_timer *w, int revents)
+ {
+ ev_timer_stop (EV_A_ w);
+
+ /* now it's one second after the most recent passwd change */
+ }
+
+ static void
+ stat_cb (EV_P_ ev_stat *w, int revents)
+ {
+ /* reset the one-second timer */
+ ev_timer_again (EV_A_ &timer);
+ }
+
+ ...
+ ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
+ ev_stat_start (loop, &passwd);
+ ev_timer_init (&timer, timer_cb, 0., 1.02);
+
+
+=head2 C<ev_idle> - when you've got nothing better to do...
+
+Idle watchers trigger events when no other events of the same or higher
+priority are pending (prepare, check and other idle watchers do not count
+as receiving "events").
+
+That is, as long as your process is busy handling sockets or timeouts
+(or even signals, imagine) of the same or higher priority it will not be
+triggered. But when your process is idle (or only lower-priority watchers
+are pending), the idle watchers are being called once per event loop
+iteration - until stopped, that is, or your process receives more events
+and becomes busy again with higher priority stuff.
+
+The most noteworthy effect is that as long as any idle watchers are
+active, the process will not block when waiting for new events.
+
+Apart from keeping your process non-blocking (which is a useful
+effect on its own sometimes), idle watchers are a good place to do
+"pseudo-background processing", or delay processing stuff to after the
+event loop has handled all outstanding events.
+
+=head3 Abusing an C<ev_idle> watcher for its side-effect
+
+As long as there is at least one active idle watcher, libev will never
+sleep unnecessarily. Or in other words, it will loop as fast as possible.
+For this to work, the idle watcher doesn't need to be invoked at all - the
+lowest priority will do.
+
+This mode of operation can be useful together with an C<ev_check> watcher,
+to do something on each event loop iteration - for example to balance load
+between different connections.
+
+See L</Abusing an ev_check watcher for its side-effect> for a longer
+example.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_idle_init (ev_idle *, callback)
+
+Initialises and configures the idle watcher - it has no parameters of any
+kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,
+believe me.
+
+=back
+
+=head3 Examples
+
+Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
+callback, free it. Also, use no error checking, as usual.
+
+ static void
+ idle_cb (struct ev_loop *loop, ev_idle *w, int revents)
+ {
+ // stop the watcher
+ ev_idle_stop (loop, w);
+
+ // now we can free it
+ free (w);
+
+ // now do something you wanted to do when the program has
+ // no longer anything immediate to do.
+ }
+
+ ev_idle *idle_watcher = malloc (sizeof (ev_idle));
+ ev_idle_init (idle_watcher, idle_cb);
+ ev_idle_start (loop, idle_watcher);
+
+
+=head2 C<ev_prepare> and C<ev_check> - customise your event loop!
+
+Prepare and check watchers are often (but not always) used in pairs:
+prepare watchers get invoked before the process blocks and check watchers
+afterwards.
+
+You I<must not> call C<ev_run> (or similar functions that enter the
+current event loop) or C<ev_loop_fork> from either C<ev_prepare> or
+C<ev_check> watchers. Other loops than the current one are fine,
+however. The rationale behind this is that you do not need to check
+for recursion in those watchers, i.e. the sequence will always be
+C<ev_prepare>, blocking, C<ev_check> so if you have one watcher of each
+kind they will always be called in pairs bracketing the blocking call.
+
+Their main purpose is to integrate other event mechanisms into libev and
+their use is somewhat advanced. They could be used, for example, to track
+variable changes, implement your own watchers, integrate net-snmp or a
+coroutine library and lots more. They are also occasionally useful if
+you cache some data and want to flush it before blocking (for example,
+in X programs you might want to do an C<XFlush ()> in an C<ev_prepare>
+watcher).
+
+This is done by examining in each prepare call which file descriptors
+need to be watched by the other library, registering C<ev_io> watchers
+for them and starting an C<ev_timer> watcher for any timeouts (many
+libraries provide exactly this functionality). Then, in the check watcher,
+you check for any events that occurred (by checking the pending status
+of all watchers and stopping them) and call back into the library. The
+I/O and timer callbacks will never actually be called (but must be valid
+nevertheless, because you never know, you know?).
+
+As another example, the Perl Coro module uses these hooks to integrate
+coroutines into libev programs, by yielding to other active coroutines
+during each prepare and only letting the process block if no coroutines
+are ready to run (it's actually more complicated: it only runs coroutines
+with priority higher than or equal to the event loop and one coroutine
+of lower priority, but only once, using idle watchers to keep the event
+loop from blocking if lower-priority coroutines are active, thus mapping
+low-priority coroutines to idle/background tasks).
+
+When used for this purpose, it is recommended to give C<ev_check> watchers
+highest (C<EV_MAXPRI>) priority, to ensure that they are being run before
+any other watchers after the poll (this doesn't matter for C<ev_prepare>
+watchers).
+
+Also, C<ev_check> watchers (and C<ev_prepare> watchers, too) should not
+activate ("feed") events into libev. While libev fully supports this, they
+might get executed before other C<ev_check> watchers did their job. As
+C<ev_check> watchers are often used to embed other (non-libev) event
+loops those other event loops might be in an unusable state until their
+C<ev_check> watcher ran (always remind yourself to coexist peacefully with
+others).
+
+=head3 Abusing an C<ev_check> watcher for its side-effect
+
+C<ev_check> (and less often also C<ev_prepare>) watchers can also be
+useful because they are called once per event loop iteration. For
+example, if you want to handle a large number of connections fairly, you
+normally only do a bit of work for each active connection, and if there
+is more work to do, you wait for the next event loop iteration, so other
+connections have a chance of making progress.
+
+Using an C<ev_check> watcher is almost enough: it will be called on the
+next event loop iteration. However, that isn't as soon as possible -
+without external events, your C<ev_check> watcher will not be invoked.
+
+This is where C<ev_idle> watchers come in handy - all you need is a
+single global idle watcher that is active as long as you have one active
+C<ev_check> watcher. The C<ev_idle> watcher makes sure the event loop
+will not sleep, and the C<ev_check> watcher makes sure a callback gets
+invoked. Neither watcher alone can do that.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_prepare_init (ev_prepare *, callback)
+
+=item ev_check_init (ev_check *, callback)
+
+Initialises and configures the prepare or check watcher - they have no
+parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>
+macros, but using them is utterly, utterly, utterly and completely
+pointless.
+
+=back
+
+=head3 Examples
+
+There are a number of principal ways to embed other event loops or modules
+into libev. Here are some ideas on how to include libadns into libev
+(there is a Perl module named C<EV::ADNS> that does this, which you could
+use as a working example. Another Perl module named C<EV::Glib> embeds a
+Glib main context into libev, and finally, C<Glib::EV> embeds EV into the
+Glib event loop).
+
+Method 1: Add IO watchers and a timeout watcher in a prepare handler,
+and in a check watcher, destroy them and call into libadns. What follows
+is pseudo-code only of course. This requires you to either use a low
+priority for the check watcher or use C<ev_clear_pending> explicitly, as
+the callbacks for the IO/timeout watchers might not have been called yet.
+
+ static ev_io iow [nfd];
+ static ev_timer tw;
+
+ static void
+ io_cb (struct ev_loop *loop, ev_io *w, int revents)
+ {
+ }
+
+ // create io watchers for each fd and a timer before blocking
+ static void
+ adns_prepare_cb (struct ev_loop *loop, ev_prepare *w, int revents)
+ {
+ int timeout = 3600000;
+ struct pollfd fds [nfd];
+ // actual code will need to loop here and realloc etc.
+ adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
+
+ /* the callback is illegal, but won't be called as we stop during check */
+ ev_timer_init (&tw, 0, timeout * 1e-3, 0.);
+ ev_timer_start (loop, &tw);
+
+ // create one ev_io per pollfd
+ for (int i = 0; i < nfd; ++i)
+ {
+ ev_io_init (iow + i, io_cb, fds [i].fd,
+ ((fds [i].events & POLLIN ? EV_READ : 0)
+ | (fds [i].events & POLLOUT ? EV_WRITE : 0)));
+
+ fds [i].revents = 0;
+ ev_io_start (loop, iow + i);
+ }
+ }
+
+ // stop all watchers after blocking
+ static void
+ adns_check_cb (struct ev_loop *loop, ev_check *w, int revents)
+ {
+ ev_timer_stop (loop, &tw);
+
+ for (int i = 0; i < nfd; ++i)
+ {
+ // set the relevant poll flags
+ // could also call adns_processreadable etc. here
+ struct pollfd *fd = fds + i;
+ int revents = ev_clear_pending (iow + i);
+ if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
+ if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
+
+ // now stop the watcher
+ ev_io_stop (loop, iow + i);
+ }
+
+ adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
+ }
+
+Method 2: This would be just like method 1, but you run C<adns_afterpoll>
+in the prepare watcher and would dispose of the check watcher.
+
+Method 3: If the module to be embedded supports explicit event
+notification (libadns does), you can also make use of the actual watcher
+callbacks, and only destroy/create the watchers in the prepare watcher.
+
+ static void
+ timer_cb (EV_P_ ev_timer *w, int revents)
+ {
+ adns_state ads = (adns_state)w->data;
+ update_now (EV_A);
+
+ adns_processtimeouts (ads, &tv_now);
+ }
+
+ static void
+ io_cb (EV_P_ ev_io *w, int revents)
+ {
+ adns_state ads = (adns_state)w->data;
+ update_now (EV_A);
+
+ if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
+ if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
+ }
+
+ // do not ever call adns_afterpoll
+
+Method 4: Do not use a prepare or check watcher because the module you
+want to embed is not flexible enough to support it. Instead, you can
+override their poll function. The drawback with this solution is that the
+main loop is now no longer controllable by EV. The C<Glib::EV> module uses
+this approach, effectively embedding EV as a client into the horrible
+libglib event loop.
+
+ static gint
+ event_poll_func (GPollFD *fds, guint nfds, gint timeout)
+ {
+ int got_events = 0;
+
+ for (n = 0; n < nfds; ++n)
+ // create/start io watcher that sets the relevant bits in fds[n] and increment got_events
+
+ if (timeout >= 0)
+ // create/start timer
+
+ // poll
+ ev_run (EV_A_ 0);
+
+ // stop timer again
+ if (timeout >= 0)
+ ev_timer_stop (EV_A_ &to);
+
+ // stop io watchers again - their callbacks should have set
+ for (n = 0; n < nfds; ++n)
+ ev_io_stop (EV_A_ iow [n]);
+
+ return got_events;
+ }
+
+
+=head2 C<ev_embed> - when one backend isn't enough...
+
+This is a rather advanced watcher type that lets you embed one event loop
+into another (currently only C<ev_io> events are supported in the embedded
+loop, other types of watchers might be handled in a delayed or incorrect
+fashion and must not be used).
+
+There are primarily two reasons you would want that: work around bugs and
+prioritise I/O.
+
+As an example for a bug workaround, the kqueue backend might only support
+sockets on some platform, so it is unusable as generic backend, but you
+still want to make use of it because you have many sockets and it scales
+so nicely. In this case, you would create a kqueue-based loop and embed
+it into your default loop (which might use e.g. poll). Overall operation
+will be a bit slower because first libev has to call C<poll> and then
+C<kevent>, but at least you can use both mechanisms for what they are
+best: C<kqueue> for scalable sockets and C<poll> if you want it to work :)
+
+As for prioritising I/O: under rare circumstances you have the case where
+some fds have to be watched and handled very quickly (with low latency),
+and even priorities and idle watchers might have too much overhead. In
+this case you would put all the high priority stuff in one loop and all
+the rest in a second one, and embed the second one in the first.
+
+As long as the watcher is active, the callback will be invoked every
+time there might be events pending in the embedded loop. The callback
+must then call C<ev_embed_sweep (mainloop, watcher)> to make a single
+sweep and invoke their callbacks (the callback doesn't need to invoke the
+C<ev_embed_sweep> function directly, it could also start an idle watcher
+to give the embedded loop strictly lower priority for example).
+
+You can also set the callback to C<0>, in which case the embed watcher
+will automatically execute the embedded loop sweep whenever necessary.
+
+Fork detection will be handled transparently while the C<ev_embed> watcher
+is active, i.e., the embedded loop will automatically be forked when the
+embedding loop forks. In other cases, the user is responsible for calling
+C<ev_loop_fork> on the embedded loop.
+
+Unfortunately, not all backends are embeddable: only the ones returned by
+C<ev_embeddable_backends> are, which, unfortunately, does not include any
+portable one.
+
+So when you want to use this feature you will always have to be prepared
+that you cannot get an embeddable loop. The recommended way to get around
+this is to have a separate variables for your embeddable loop, try to
+create it, and if that fails, use the normal loop for everything.
+
+=head3 C<ev_embed> and fork
+
+While the C<ev_embed> watcher is running, forks in the embedding loop will
+automatically be applied to the embedded loop as well, so no special
+fork handling is required in that case. When the watcher is not running,
+however, it is still the task of the libev user to call C<ev_loop_fork ()>
+as applicable.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)
+
+=item ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)
+
+Configures the watcher to embed the given loop, which must be
+embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be
+invoked automatically, otherwise it is the responsibility of the callback
+to invoke it (it will continue to be called until the sweep has been done,
+if you do not want that, you need to temporarily stop the embed watcher).
+
+=item ev_embed_sweep (loop, ev_embed *)
+
+Make a single, non-blocking sweep over the embedded loop. This works
+similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
+appropriate way for embedded loops.
+
+=item struct ev_loop *other [read-only]
+
+The embedded event loop.
+
+=back
+
+=head3 Examples
+
+Example: Try to get an embeddable event loop and embed it into the default
+event loop. If that is not possible, use the default loop. The default
+loop is stored in C<loop_hi>, while the embeddable loop is stored in
+C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be
+used).
+
+ struct ev_loop *loop_hi = ev_default_init (0);
+ struct ev_loop *loop_lo = 0;
+ ev_embed embed;
+
+ // see if there is a chance of getting one that works
+ // (remember that a flags value of 0 means autodetection)
+ loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
+ ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
+ : 0;
+
+ // if we got one, then embed it, otherwise default to loop_hi
+ if (loop_lo)
+ {
+ ev_embed_init (&embed, 0, loop_lo);
+ ev_embed_start (loop_hi, &embed);
+ }
+ else
+ loop_lo = loop_hi;
+
+Example: Check if kqueue is available but not recommended and create
+a kqueue backend for use with sockets (which usually work with any
+kqueue implementation). Store the kqueue/socket-only event loop in
+C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
+
+ struct ev_loop *loop = ev_default_init (0);
+ struct ev_loop *loop_socket = 0;
+ ev_embed embed;
+
+ if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
+ if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
+ {
+ ev_embed_init (&embed, 0, loop_socket);
+ ev_embed_start (loop, &embed);
+ }
+
+ if (!loop_socket)
+ loop_socket = loop;
+
+ // now use loop_socket for all sockets, and loop for everything else
+
+
+=head2 C<ev_fork> - the audacity to resume the event loop after a fork
+
+Fork watchers are called when a C<fork ()> was detected (usually because
+whoever is a good citizen cared to tell libev about it by calling
+C<ev_loop_fork>). The invocation is done before the event loop blocks next
+and before C<ev_check> watchers are being called, and only in the child
+after the fork. If whoever good citizen calling C<ev_default_fork> cheats
+and calls it in the wrong process, the fork handlers will be invoked, too,
+of course.
+
+=head3 The special problem of life after fork - how is it possible?
+
+Most uses of C<fork ()> consist of forking, then some simple calls to set
+up/change the process environment, followed by a call to C<exec()>. This
+sequence should be handled by libev without any problems.
+
+This changes when the application actually wants to do event handling
+in the child, or both parent in child, in effect "continuing" after the
+fork.
+
+The default mode of operation (for libev, with application help to detect
+forks) is to duplicate all the state in the child, as would be expected
+when I<either> the parent I<or> the child process continues.
+
+When both processes want to continue using libev, then this is usually the
+wrong result. In that case, usually one process (typically the parent) is
+supposed to continue with all watchers in place as before, while the other
+process typically wants to start fresh, i.e. without any active watchers.
+
+The cleanest and most efficient way to achieve that with libev is to
+simply create a new event loop, which of course will be "empty", and
+use that for new watchers. This has the advantage of not touching more
+memory than necessary, and thus avoiding the copy-on-write, and the
+disadvantage of having to use multiple event loops (which do not support
+signal watchers).
+
+When this is not possible, or you want to use the default loop for
+other reasons, then in the process that wants to start "fresh", call
+C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
+Destroying the default loop will "orphan" (not stop) all registered
+watchers, so you have to be careful not to execute code that modifies
+those watchers. Note also that in that case, you have to re-register any
+signal watchers.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_fork_init (ev_fork *, callback)
+
+Initialises and configures the fork watcher - it has no parameters of any
+kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
+really.
+
+=back
+
+
+=head2 C<ev_cleanup> - even the best things end
+
+Cleanup watchers are called just before the event loop is being destroyed
+by a call to C<ev_loop_destroy>.
+
+While there is no guarantee that the event loop gets destroyed, cleanup
+watchers provide a convenient method to install cleanup hooks for your
+program, worker threads and so on - you just to make sure to destroy the
+loop when you want them to be invoked.
+
+Cleanup watchers are invoked in the same way as any other watcher. Unlike
+all other watchers, they do not keep a reference to the event loop (which
+makes a lot of sense if you think about it). Like all other watchers, you
+can call libev functions in the callback, except C<ev_cleanup_start>.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_cleanup_init (ev_cleanup *, callback)
+
+Initialises and configures the cleanup watcher - it has no parameters of
+any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
+pointless, I assure you.
+
+=back
+
+Example: Register an atexit handler to destroy the default loop, so any
+cleanup functions are called.
+
+ static void
+ program_exits (void)
+ {
+ ev_loop_destroy (EV_DEFAULT_UC);
+ }
+
+ ...
+ atexit (program_exits);
+
+
+=head2 C<ev_async> - how to wake up an event loop
+
+In general, you cannot use an C<ev_loop> from multiple threads or other
+asynchronous sources such as signal handlers (as opposed to multiple event
+loops - those are of course safe to use in different threads).
+
+Sometimes, however, you need to wake up an event loop you do not control,
+for example because it belongs to another thread. This is what C<ev_async>
+watchers do: as long as the C<ev_async> watcher is active, you can signal
+it by calling C<ev_async_send>, which is thread- and signal safe.
+
+This functionality is very similar to C<ev_signal> watchers, as signals,
+too, are asynchronous in nature, and signals, too, will be compressed
+(i.e. the number of callback invocations may be less than the number of
+C<ev_async_send> calls). In fact, you could use signal watchers as a kind
+of "global async watchers" by using a watcher on an otherwise unused
+signal, and C<ev_feed_signal> to signal this watcher from another thread,
+even without knowing which loop owns the signal.
+
+=head3 Queueing
+
+C<ev_async> does not support queueing of data in any way. The reason
+is that the author does not know of a simple (or any) algorithm for a
+multiple-writer-single-reader queue that works in all cases and doesn't
+need elaborate support such as pthreads or unportable memory access
+semantics.
+
+That means that if you want to queue data, you have to provide your own
+queue. But at least I can tell you how to implement locking around your
+queue:
+
+=over 4
+
+=item queueing from a signal handler context
+
+To implement race-free queueing, you simply add to the queue in the signal
+handler but you block the signal handler in the watcher callback. Here is
+an example that does that for some fictitious SIGUSR1 handler:
+
+ static ev_async mysig;
+
+ static void
+ sigusr1_handler (void)
+ {
+ sometype data;
+
+ // no locking etc.
+ queue_put (data);
+ ev_async_send (EV_DEFAULT_ &mysig);
+ }
+
+ static void
+ mysig_cb (EV_P_ ev_async *w, int revents)
+ {
+ sometype data;
+ sigset_t block, prev;
+
+ sigemptyset (&block);
+ sigaddset (&block, SIGUSR1);
+ sigprocmask (SIG_BLOCK, &block, &prev);
+
+ while (queue_get (&data))
+ process (data);
+
+ if (sigismember (&prev, SIGUSR1)
+ sigprocmask (SIG_UNBLOCK, &block, 0);
+ }
+
+(Note: pthreads in theory requires you to use C<pthread_setmask>
+instead of C<sigprocmask> when you use threads, but libev doesn't do it
+either...).
+
+=item queueing from a thread context
+
+The strategy for threads is different, as you cannot (easily) block
+threads but you can easily preempt them, so to queue safely you need to
+employ a traditional mutex lock, such as in this pthread example:
+
+ static ev_async mysig;
+ static pthread_mutex_t mymutex = PTHREAD_MUTEX_INITIALIZER;
+
+ static void
+ otherthread (void)
+ {
+ // only need to lock the actual queueing operation
+ pthread_mutex_lock (&mymutex);
+ queue_put (data);
+ pthread_mutex_unlock (&mymutex);
+
+ ev_async_send (EV_DEFAULT_ &mysig);
+ }
+
+ static void
+ mysig_cb (EV_P_ ev_async *w, int revents)
+ {
+ pthread_mutex_lock (&mymutex);
+
+ while (queue_get (&data))
+ process (data);
+
+ pthread_mutex_unlock (&mymutex);
+ }
+
+=back
+
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_async_init (ev_async *, callback)
+
+Initialises and configures the async watcher - it has no parameters of any
+kind. There is a C<ev_async_set> macro, but using it is utterly pointless,
+trust me.
+
+=item ev_async_send (loop, ev_async *)
+
+Sends/signals/activates the given C<ev_async> watcher, that is, feeds
+an C<EV_ASYNC> event on the watcher into the event loop, and instantly
+returns.
+
+Unlike C<ev_feed_event>, this call is safe to do from other threads,
+signal or similar contexts (see the discussion of C<EV_ATOMIC_T> in the
+embedding section below on what exactly this means).
+
+Note that, as with other watchers in libev, multiple events might get
+compressed into a single callback invocation (another way to look at
+this is that C<ev_async> watchers are level-triggered: they are set on
+C<ev_async_send>, reset when the event loop detects that).
+
+This call incurs the overhead of at most one extra system call per event
+loop iteration, if the event loop is blocked, and no syscall at all if
+the event loop (or your program) is processing events. That means that
+repeated calls are basically free (there is no need to avoid calls for
+performance reasons) and that the overhead becomes smaller (typically
+zero) under load.
+
+=item bool = ev_async_pending (ev_async *)
+
+Returns a non-zero value when C<ev_async_send> has been called on the
+watcher but the event has not yet been processed (or even noted) by the
+event loop.
+
+C<ev_async_send> sets a flag in the watcher and wakes up the loop. When
+the loop iterates next and checks for the watcher to have become active,
+it will reset the flag again. C<ev_async_pending> can be used to very
+quickly check whether invoking the loop might be a good idea.
+
+Not that this does I<not> check whether the watcher itself is pending,
+only whether it has been requested to make this watcher pending: there
+is a time window between the event loop checking and resetting the async
+notification, and the callback being invoked.
+
+=back
+
+
+=head1 OTHER FUNCTIONS
+
+There are some other functions of possible interest. Described. Here. Now.
+
+=over 4
+
+=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback, arg)
+
+This function combines a simple timer and an I/O watcher, calls your
+callback on whichever event happens first and automatically stops both
+watchers. This is useful if you want to wait for a single event on an fd
+or timeout without having to allocate/configure/start/stop/free one or
+more watchers yourself.
+
+If C<fd> is less than 0, then no I/O watcher will be started and the
+C<events> argument is being ignored. Otherwise, an C<ev_io> watcher for
+the given C<fd> and C<events> set will be created and started.
+
+If C<timeout> is less than 0, then no timeout watcher will be
+started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
+repeat = 0) will be started. C<0> is a valid timeout.
+
+The callback has the type C<void (*cb)(int revents, void *arg)> and is
+passed an C<revents> set like normal event callbacks (a combination of
+C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
+value passed to C<ev_once>. Note that it is possible to receive I<both>
+a timeout and an io event at the same time - you probably should give io
+events precedence.
+
+Example: wait up to ten seconds for data to appear on STDIN_FILENO.
+
+ static void stdin_ready (int revents, void *arg)
+ {
+ if (revents & EV_READ)
+ /* stdin might have data for us, joy! */;
+ else if (revents & EV_TIMER)
+ /* doh, nothing entered */;
+ }
+
+ ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
+
+=item ev_feed_fd_event (loop, int fd, int revents)
+
+Feed an event on the given fd, as if a file descriptor backend detected
+the given events.
+
+=item ev_feed_signal_event (loop, int signum)
+
+Feed an event as if the given signal occurred. See also C<ev_feed_signal>,
+which is async-safe.
+
+=back
+
+
+=head1 COMMON OR USEFUL IDIOMS (OR BOTH)
+
+This section explains some common idioms that are not immediately
+obvious. Note that examples are sprinkled over the whole manual, and this
+section only contains stuff that wouldn't fit anywhere else.
+
+=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
+
+Each watcher has, by default, a C<void *data> member that you can read
+or modify at any time: libev will completely ignore it. This can be used
+to associate arbitrary data with your watcher. If you need more data and
+don't want to allocate memory separately and store a pointer to it in that
+data member, you can also "subclass" the watcher type and provide your own
+data:
+
+ struct my_io
+ {
+ ev_io io;
+ int otherfd;
+ void *somedata;
+ struct whatever *mostinteresting;
+ };
+
+ ...
+ struct my_io w;
+ ev_io_init (&w.io, my_cb, fd, EV_READ);
+
+And since your callback will be called with a pointer to the watcher, you
+can cast it back to your own type:
+
+ static void my_cb (struct ev_loop *loop, ev_io *w_, int revents)
+ {
+ struct my_io *w = (struct my_io *)w_;
+ ...
+ }
+
+More interesting and less C-conformant ways of casting your callback
+function type instead have been omitted.
+
+=head2 BUILDING YOUR OWN COMPOSITE WATCHERS
+
+Another common scenario is to use some data structure with multiple
+embedded watchers, in effect creating your own watcher that combines
+multiple libev event sources into one "super-watcher":
+
+ struct my_biggy
+ {
+ int some_data;
+ ev_timer t1;
+ ev_timer t2;
+ }
+
+In this case getting the pointer to C<my_biggy> is a bit more
+complicated: Either you store the address of your C<my_biggy> struct in
+the C<data> member of the watcher (for woozies or C++ coders), or you need
+to use some pointer arithmetic using C<offsetof> inside your watchers (for
+real programmers):
+
+ #include <stddef.h>
+
+ static void
+ t1_cb (EV_P_ ev_timer *w, int revents)
+ {
+ struct my_biggy big = (struct my_biggy *)
+ (((char *)w) - offsetof (struct my_biggy, t1));
+ }
+
+ static void
+ t2_cb (EV_P_ ev_timer *w, int revents)
+ {
+ struct my_biggy big = (struct my_biggy *)
+ (((char *)w) - offsetof (struct my_biggy, t2));
+ }
+
+=head2 AVOIDING FINISHING BEFORE RETURNING
+
+Often you have structures like this in event-based programs:
+
+ callback ()
+ {
+ free (request);
+ }
+
+ request = start_new_request (..., callback);
+
+The intent is to start some "lengthy" operation. The C<request> could be
+used to cancel the operation, or do other things with it.
+
+It's not uncommon to have code paths in C<start_new_request> that
+immediately invoke the callback, for example, to report errors. Or you add
+some caching layer that finds that it can skip the lengthy aspects of the
+operation and simply invoke the callback with the result.
+
+The problem here is that this will happen I<before> C<start_new_request>
+has returned, so C<request> is not set.
+
+Even if you pass the request by some safer means to the callback, you
+might want to do something to the request after starting it, such as
+canceling it, which probably isn't working so well when the callback has
+already been invoked.
+
+A common way around all these issues is to make sure that
+C<start_new_request> I<always> returns before the callback is invoked. If
+C<start_new_request> immediately knows the result, it can artificially
+delay invoking the callback by using a C<prepare> or C<idle> watcher for
+example, or more sneakily, by reusing an existing (stopped) watcher and
+pushing it into the pending queue:
+
+ ev_set_cb (watcher, callback);
+ ev_feed_event (EV_A_ watcher, 0);
+
+This way, C<start_new_request> can safely return before the callback is
+invoked, while not delaying callback invocation too much.
+
+=head2 MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS
+
+Often (especially in GUI toolkits) there are places where you have
+I<modal> interaction, which is most easily implemented by recursively
+invoking C<ev_run>.
+
+This brings the problem of exiting - a callback might want to finish the
+main C<ev_run> call, but not the nested one (e.g. user clicked "Quit", but
+a modal "Are you sure?" dialog is still waiting), or just the nested one
+and not the main one (e.g. user clocked "Ok" in a modal dialog), or some
+other combination: In these cases, a simple C<ev_break> will not work.
+
+The solution is to maintain "break this loop" variable for each C<ev_run>
+invocation, and use a loop around C<ev_run> until the condition is
+triggered, using C<EVRUN_ONCE>:
+
+ // main loop
+ int exit_main_loop = 0;
+
+ while (!exit_main_loop)
+ ev_run (EV_DEFAULT_ EVRUN_ONCE);
+
+ // in a modal watcher
+ int exit_nested_loop = 0;
+
+ while (!exit_nested_loop)
+ ev_run (EV_A_ EVRUN_ONCE);
+
+To exit from any of these loops, just set the corresponding exit variable:
+
+ // exit modal loop
+ exit_nested_loop = 1;
+
+ // exit main program, after modal loop is finished
+ exit_main_loop = 1;
+
+ // exit both
+ exit_main_loop = exit_nested_loop = 1;
+
+=head2 THREAD LOCKING EXAMPLE
+
+Here is a fictitious example of how to run an event loop in a different
+thread from where callbacks are being invoked and watchers are
+created/added/removed.
+
+For a real-world example, see the C<EV::Loop::Async> perl module,
+which uses exactly this technique (which is suited for many high-level
+languages).
+
+The example uses a pthread mutex to protect the loop data, a condition
+variable to wait for callback invocations, an async watcher to notify the
+event loop thread and an unspecified mechanism to wake up the main thread.
+
+First, you need to associate some data with the event loop:
+
+ typedef struct {
+ mutex_t lock; /* global loop lock */
+ ev_async async_w;
+ thread_t tid;
+ cond_t invoke_cv;
+ } userdata;
+
+ void prepare_loop (EV_P)
+ {
+ // for simplicity, we use a static userdata struct.
+ static userdata u;
+
+ ev_async_init (&u->async_w, async_cb);
+ ev_async_start (EV_A_ &u->async_w);
+
+ pthread_mutex_init (&u->lock, 0);
+ pthread_cond_init (&u->invoke_cv, 0);
+
+ // now associate this with the loop
+ ev_set_userdata (EV_A_ u);
+ ev_set_invoke_pending_cb (EV_A_ l_invoke);
+ ev_set_loop_release_cb (EV_A_ l_release, l_acquire);
+
+ // then create the thread running ev_run
+ pthread_create (&u->tid, 0, l_run, EV_A);
+ }
+
+The callback for the C<ev_async> watcher does nothing: the watcher is used
+solely to wake up the event loop so it takes notice of any new watchers
+that might have been added:
+
+ static void
+ async_cb (EV_P_ ev_async *w, int revents)
+ {
+ // just used for the side effects
+ }
+
+The C<l_release> and C<l_acquire> callbacks simply unlock/lock the mutex
+protecting the loop data, respectively.
+
+ static void
+ l_release (EV_P)
+ {
+ userdata *u = ev_userdata (EV_A);
+ pthread_mutex_unlock (&u->lock);
+ }
+
+ static void
+ l_acquire (EV_P)
+ {
+ userdata *u = ev_userdata (EV_A);
+ pthread_mutex_lock (&u->lock);
+ }
+
+The event loop thread first acquires the mutex, and then jumps straight
+into C<ev_run>:
+
+ void *
+ l_run (void *thr_arg)
+ {
+ struct ev_loop *loop = (struct ev_loop *)thr_arg;
+
+ l_acquire (EV_A);
+ pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
+ ev_run (EV_A_ 0);
+ l_release (EV_A);
+
+ return 0;
+ }
+
+Instead of invoking all pending watchers, the C<l_invoke> callback will
+signal the main thread via some unspecified mechanism (signals? pipe
+writes? C<Async::Interrupt>?) and then waits until all pending watchers
+have been called (in a while loop because a) spurious wakeups are possible
+and b) skipping inter-thread-communication when there are no pending
+watchers is very beneficial):
+
+ static void
+ l_invoke (EV_P)
+ {
+ userdata *u = ev_userdata (EV_A);
+
+ while (ev_pending_count (EV_A))
+ {
+ wake_up_other_thread_in_some_magic_or_not_so_magic_way ();
+ pthread_cond_wait (&u->invoke_cv, &u->lock);
+ }
+ }
+
+Now, whenever the main thread gets told to invoke pending watchers, it
+will grab the lock, call C<ev_invoke_pending> and then signal the loop
+thread to continue:
+
+ static void
+ real_invoke_pending (EV_P)
+ {
+ userdata *u = ev_userdata (EV_A);
+
+ pthread_mutex_lock (&u->lock);
+ ev_invoke_pending (EV_A);
+ pthread_cond_signal (&u->invoke_cv);
+ pthread_mutex_unlock (&u->lock);
+ }
+
+Whenever you want to start/stop a watcher or do other modifications to an
+event loop, you will now have to lock:
+
+ ev_timer timeout_watcher;
+ userdata *u = ev_userdata (EV_A);
+
+ ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+
+ pthread_mutex_lock (&u->lock);
+ ev_timer_start (EV_A_ &timeout_watcher);
+ ev_async_send (EV_A_ &u->async_w);
+ pthread_mutex_unlock (&u->lock);
+
+Note that sending the C<ev_async> watcher is required because otherwise
+an event loop currently blocking in the kernel will have no knowledge
+about the newly added timer. By waking up the loop it will pick up any new
+watchers in the next event loop iteration.
+
+=head2 THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS
+
+While the overhead of a callback that e.g. schedules a thread is small, it
+is still an overhead. If you embed libev, and your main usage is with some
+kind of threads or coroutines, you might want to customise libev so that
+doesn't need callbacks anymore.
+
+Imagine you have coroutines that you can switch to using a function
+C<switch_to (coro)>, that libev runs in a coroutine called C<libev_coro>
+and that due to some magic, the currently active coroutine is stored in a
+global called C<current_coro>. Then you can build your own "wait for libev
+event" primitive by changing C<EV_CB_DECLARE> and C<EV_CB_INVOKE> (note
+the differing C<;> conventions):
+
+ #define EV_CB_DECLARE(type) struct my_coro *cb;
+ #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb)
+
+That means instead of having a C callback function, you store the
+coroutine to switch to in each watcher, and instead of having libev call
+your callback, you instead have it switch to that coroutine.
+
+A coroutine might now wait for an event with a function called
+C<wait_for_event>. (the watcher needs to be started, as always, but it doesn't
+matter when, or whether the watcher is active or not when this function is
+called):
+
+ void
+ wait_for_event (ev_watcher *w)
+ {
+ ev_set_cb (w, current_coro);
+ switch_to (libev_coro);
+ }
+
+That basically suspends the coroutine inside C<wait_for_event> and
+continues the libev coroutine, which, when appropriate, switches back to
+this or any other coroutine.
+
+You can do similar tricks if you have, say, threads with an event queue -
+instead of storing a coroutine, you store the queue object and instead of
+switching to a coroutine, you push the watcher onto the queue and notify
+any waiters.
+
+To embed libev, see L</EMBEDDING>, but in short, it's easiest to create two
+files, F<my_ev.h> and F<my_ev.c> that include the respective libev files:
+
+ // my_ev.h
+ #define EV_CB_DECLARE(type) struct my_coro *cb;
+ #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb)
+ #include "../libev/ev.h"
+
+ // my_ev.c
+ #define EV_H "my_ev.h"
+ #include "../libev/ev.c"
+
+And then use F<my_ev.h> when you would normally use F<ev.h>, and compile
+F<my_ev.c> into your project. When properly specifying include paths, you
+can even use F<ev.h> as header file name directly.
+
+
+=head1 LIBEVENT EMULATION
+
+Libev offers a compatibility emulation layer for libevent. It cannot
+emulate the internals of libevent, so here are some usage hints:
+
+=over 4
+
+=item * Only the libevent-1.4.1-beta API is being emulated.
+
+This was the newest libevent version available when libev was implemented,
+and is still mostly unchanged in 2010.
+
+=item * Use it by including <event.h>, as usual.
+
+=item * The following members are fully supported: ev_base, ev_callback,
+ev_arg, ev_fd, ev_res, ev_events.
+
+=item * Avoid using ev_flags and the EVLIST_*-macros, while it is
+maintained by libev, it does not work exactly the same way as in libevent (consider
+it a private API).
+
+=item * Priorities are not currently supported. Initialising priorities
+will fail and all watchers will have the same priority, even though there
+is an ev_pri field.
+
+=item * In libevent, the last base created gets the signals, in libev, the
+base that registered the signal gets the signals.
+
+=item * Other members are not supported.
+
+=item * The libev emulation is I<not> ABI compatible to libevent, you need
+to use the libev header file and library.
+
+=back
+
+=head1 C++ SUPPORT
+
+=head2 C API
+
+The normal C API should work fine when used from C++: both ev.h and the
+libev sources can be compiled as C++. Therefore, code that uses the C API
+will work fine.
+
+Proper exception specifications might have to be added to callbacks passed
+to libev: exceptions may be thrown only from watcher callbacks, all other
+callbacks (allocator, syserr, loop acquire/release and periodic reschedule
+callbacks) must not throw exceptions, and might need a C<noexcept>
+specification. If you have code that needs to be compiled as both C and
+C++ you can use the C<EV_NOEXCEPT> macro for this:
+
+ static void
+ fatal_error (const char *msg) EV_NOEXCEPT
+ {
+ perror (msg);
+ abort ();
+ }
+
+ ...
+ ev_set_syserr_cb (fatal_error);
+
+The only API functions that can currently throw exceptions are C<ev_run>,
+C<ev_invoke>, C<ev_invoke_pending> and C<ev_loop_destroy> (the latter
+because it runs cleanup watchers).
+
+Throwing exceptions in watcher callbacks is only supported if libev itself
+is compiled with a C++ compiler or your C and C++ environments allow
+throwing exceptions through C libraries (most do).
+
+=head2 C++ API
+
+Libev comes with some simplistic wrapper classes for C++ that mainly allow
+you to use some convenience methods to start/stop watchers and also change
+the callback model to a model using method callbacks on objects.
+
+To use it,
+
+ #include <ev++.h>
+
+This automatically includes F<ev.h> and puts all of its definitions (many
+of them macros) into the global namespace. All C++ specific things are
+put into the C<ev> namespace. It should support all the same embedding
+options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
+
+Care has been taken to keep the overhead low. The only data member the C++
+classes add (compared to plain C-style watchers) is the event loop pointer
+that the watcher is associated with (or no additional members at all if
+you disable C<EV_MULTIPLICITY> when embedding libev).
+
+Currently, functions, static and non-static member functions and classes
+with C<operator ()> can be used as callbacks. Other types should be easy
+to add as long as they only need one additional pointer for context. If
+you need support for other types of functors please contact the author
+(preferably after implementing it).
+
+For all this to work, your C++ compiler either has to use the same calling
+conventions as your C compiler (for static member functions), or you have
+to embed libev and compile libev itself as C++.
+
+Here is a list of things available in the C<ev> namespace:
+
+=over 4
+
+=item C<ev::READ>, C<ev::WRITE> etc.
+
+These are just enum values with the same values as the C<EV_READ> etc.
+macros from F<ev.h>.
+
+=item C<ev::tstamp>, C<ev::now>
+
+Aliases to the same types/functions as with the C<ev_> prefix.
+
+=item C<ev::io>, C<ev::timer>, C<ev::periodic>, C<ev::idle>, C<ev::sig> etc.
+
+For each C<ev_TYPE> watcher in F<ev.h> there is a corresponding class of
+the same name in the C<ev> namespace, with the exception of C<ev_signal>
+which is called C<ev::sig> to avoid clashes with the C<signal> macro
+defined by many implementations.
+
+All of those classes have these methods:
+
+=over 4
+
+=item ev::TYPE::TYPE ()
+
+=item ev::TYPE::TYPE (loop)
+
+=item ev::TYPE::~TYPE
+
+The constructor (optionally) takes an event loop to associate the watcher
+with. If it is omitted, it will use C<EV_DEFAULT>.
+
+The constructor calls C<ev_init> for you, which means you have to call the
+C<set> method before starting it.
+
+It will not set a callback, however: You have to call the templated C<set>
+method to set a callback before you can start the watcher.
+
+(The reason why you have to use a method is a limitation in C++ which does
+not allow explicit template arguments for constructors).
+
+The destructor automatically stops the watcher if it is active.
+
+=item w->set<class, &class::method> (object *)
+
+This method sets the callback method to call. The method has to have a
+signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as
+first argument and the C<revents> as second. The object must be given as
+parameter and is stored in the C<data> member of the watcher.
+
+This method synthesizes efficient thunking code to call your method from
+the C callback that libev requires. If your compiler can inline your
+callback (i.e. it is visible to it at the place of the C<set> call and
+your compiler is good :), then the method will be fully inlined into the
+thunking function, making it as fast as a direct C callback.
+
+Example: simple class declaration and watcher initialisation
+
+ struct myclass
+ {
+ void io_cb (ev::io &w, int revents) { }
+ }
+
+ myclass obj;
+ ev::io iow;
+ iow.set <myclass, &myclass::io_cb> (&obj);
+
+=item w->set (object *)
+
+This is a variation of a method callback - leaving out the method to call
+will default the method to C<operator ()>, which makes it possible to use
+functor objects without having to manually specify the C<operator ()> all
+the time. Incidentally, you can then also leave out the template argument
+list.
+
+The C<operator ()> method prototype must be C<void operator ()(watcher &w,
+int revents)>.
+
+See the method-C<set> above for more details.
+
+Example: use a functor object as callback.
+
+ struct myfunctor
+ {
+ void operator() (ev::io &w, int revents)
+ {
+ ...
+ }
+ }
+
+ myfunctor f;
+
+ ev::io w;
+ w.set (&f);
+
+=item w->set<function> (void *data = 0)
+
+Also sets a callback, but uses a static method or plain function as
+callback. The optional C<data> argument will be stored in the watcher's
+C<data> member and is free for you to use.
+
+The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>.
+
+See the method-C<set> above for more details.
+
+Example: Use a plain function as callback.
+
+ static void io_cb (ev::io &w, int revents) { }
+ iow.set <io_cb> ();
+
+=item w->set (loop)
+
+Associates a different C<struct ev_loop> with this watcher. You can only
+do this when the watcher is inactive (and not pending either).
+
+=item w->set ([arguments])
+
+Basically the same as C<ev_TYPE_set> (except for C<ev::embed> watchers>),
+with the same arguments. Either this method or a suitable start method
+must be called at least once. Unlike the C counterpart, an active watcher
+gets automatically stopped and restarted when reconfiguring it with this
+method.
+
+For C<ev::embed> watchers this method is called C<set_embed>, to avoid
+clashing with the C<set (loop)> method.
+
+For C<ev::io> watchers there is an additional C<set> method that acepts a
+new event mask only, and internally calls C<ev_io_modfify>.
+
+=item w->start ()
+
+Starts the watcher. Note that there is no C<loop> argument, as the
+constructor already stores the event loop.
+
+=item w->start ([arguments])
+
+Instead of calling C<set> and C<start> methods separately, it is often
+convenient to wrap them in one call. Uses the same type of arguments as
+the configure C<set> method of the watcher.
+
+=item w->stop ()
+
+Stops the watcher if it is active. Again, no C<loop> argument.
+
+=item w->again () (C<ev::timer>, C<ev::periodic> only)
+
+For C<ev::timer> and C<ev::periodic>, this invokes the corresponding
+C<ev_TYPE_again> function.
+
+=item w->sweep () (C<ev::embed> only)
+
+Invokes C<ev_embed_sweep>.
+
+=item w->update () (C<ev::stat> only)
+
+Invokes C<ev_stat_stat>.
+
+=back
+
+=back
+
+Example: Define a class with two I/O and idle watchers, start the I/O
+watchers in the constructor.
+
+ class myclass
+ {
+ ev::io io ; void io_cb (ev::io &w, int revents);
+ ev::io io2 ; void io2_cb (ev::io &w, int revents);
+ ev::idle idle; void idle_cb (ev::idle &w, int revents);
+
+ myclass (int fd)
+ {
+ io .set <myclass, &myclass::io_cb > (this);
+ io2 .set <myclass, &myclass::io2_cb > (this);
+ idle.set <myclass, &myclass::idle_cb> (this);
+
+ io.set (fd, ev::WRITE); // configure the watcher
+ io.start (); // start it whenever convenient
+
+ io2.start (fd, ev::READ); // set + start in one call
+ }
+ };
+
+
+=head1 OTHER LANGUAGE BINDINGS
+
+Libev does not offer other language bindings itself, but bindings for a
+number of languages exist in the form of third-party packages. If you know
+any interesting language binding in addition to the ones listed here, drop
+me a note.
+
+=over 4
+
+=item Perl
+
+The EV module implements the full libev API and is actually used to test
+libev. EV is developed together with libev. Apart from the EV core module,
+there are additional modules that implement libev-compatible interfaces
+to C<libadns> (C<EV::ADNS>, but C<AnyEvent::DNS> is preferred nowadays),
+C<Net::SNMP> (C<Net::SNMP::EV>) and the C<libglib> event core (C<Glib::EV>
+and C<EV::Glib>).
+
+It can be found and installed via CPAN, its homepage is at
+L<http://software.schmorp.de/pkg/EV>.
+
+=item Python
+
+Python bindings can be found at L<http://code.google.com/p/pyev/>. It
+seems to be quite complete and well-documented.
+
+=item Ruby
+
+Tony Arcieri has written a ruby extension that offers access to a subset
+of the libev API and adds file handle abstractions, asynchronous DNS and
+more on top of it. It can be found via gem servers. Its homepage is at
+L<http://rev.rubyforge.org/>.
+
+Roger Pack reports that using the link order C<-lws2_32 -lmsvcrt-ruby-190>
+makes rev work even on mingw.
+
+=item Haskell
+
+A haskell binding to libev is available at
+L<http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hlibev>.
+
+=item D
+
+Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to
+be found at L<http://www.llucax.com.ar/proj/ev.d/index.html>.
+
+=item Ocaml
+
+Erkki Seppala has written Ocaml bindings for libev, to be found at
+L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
+
+=item Lua
+
+Brian Maher has written a partial interface to libev for lua (at the
+time of this writing, only C<ev_io> and C<ev_timer>), to be found at
+L<http://github.com/brimworks/lua-ev>.
+
+=item Javascript
+
+Node.js (L<http://nodejs.org>) uses libev as the underlying event library.
+
+=item Others
+
+There are others, and I stopped counting.
+
+=back
+
+
+=head1 MACRO MAGIC
+
+Libev can be compiled with a variety of options, the most fundamental
+of which is C<EV_MULTIPLICITY>. This option determines whether (most)
+functions and callbacks have an initial C<struct ev_loop *> argument.
+
+To make it easier to write programs that cope with either variant, the
+following macros are defined:
+
+=over 4
+
+=item C<EV_A>, C<EV_A_>
+
+This provides the loop I<argument> for functions, if one is required ("ev
+loop argument"). The C<EV_A> form is used when this is the sole argument,
+C<EV_A_> is used when other arguments are following. Example:
+
+ ev_unref (EV_A);
+ ev_timer_add (EV_A_ watcher);
+ ev_run (EV_A_ 0);
+
+It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
+which is often provided by the following macro.
+
+=item C<EV_P>, C<EV_P_>
+
+This provides the loop I<parameter> for functions, if one is required ("ev
+loop parameter"). The C<EV_P> form is used when this is the sole parameter,
+C<EV_P_> is used when other parameters are following. Example:
+
+ // this is how ev_unref is being declared
+ static void ev_unref (EV_P);
+
+ // this is how you can declare your typical callback
+ static void cb (EV_P_ ev_timer *w, int revents)
+
+It declares a parameter C<loop> of type C<struct ev_loop *>, quite
+suitable for use with C<EV_A>.
+
+=item C<EV_DEFAULT>, C<EV_DEFAULT_>
+
+Similar to the other two macros, this gives you the value of the default
+loop, if multiple loops are supported ("ev loop default"). The default loop
+will be initialised if it isn't already initialised.
+
+For non-multiplicity builds, these macros do nothing, so you always have
+to initialise the loop somewhere.
+
+=item C<EV_DEFAULT_UC>, C<EV_DEFAULT_UC_>
+
+Usage identical to C<EV_DEFAULT> and C<EV_DEFAULT_>, but requires that the
+default loop has been initialised (C<UC> == unchecked). Their behaviour
+is undefined when the default loop has not been initialised by a previous
+execution of C<EV_DEFAULT>, C<EV_DEFAULT_> or C<ev_default_init (...)>.
+
+It is often prudent to use C<EV_DEFAULT> when initialising the first
+watcher in a function but use C<EV_DEFAULT_UC> afterwards.
+
+=back
+
+Example: Declare and initialise a check watcher, utilising the above
+macros so it will work regardless of whether multiple loops are supported
+or not.
+
+ static void
+ check_cb (EV_P_ ev_timer *w, int revents)
+ {
+ ev_check_stop (EV_A_ w);
+ }
+
+ ev_check check;
+ ev_check_init (&check, check_cb);
+ ev_check_start (EV_DEFAULT_ &check);
+ ev_run (EV_DEFAULT_ 0);
+
+=head1 EMBEDDING
+
+Libev can (and often is) directly embedded into host
+applications. Examples of applications that embed it include the Deliantra
+Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
+and rxvt-unicode.
+
+The goal is to enable you to just copy the necessary files into your
+source directory without having to change even a single line in them, so
+you can easily upgrade by simply copying (or having a checked-out copy of
+libev somewhere in your source tree).
+
+=head2 FILESETS
+
+Depending on what features you need you need to include one or more sets of files
+in your application.
+
+=head3 CORE EVENT LOOP
+
+To include only the libev core (all the C<ev_*> functions), with manual
+configuration (no autoconf):
+
+ #define EV_STANDALONE 1
+ #include "ev.c"
+
+This will automatically include F<ev.h>, too, and should be done in a
+single C source file only to provide the function implementations. To use
+it, do the same for F<ev.h> in all files wishing to use this API (best
+done by writing a wrapper around F<ev.h> that you can include instead and
+where you can put other configuration options):
+
+ #define EV_STANDALONE 1
+ #include "ev.h"
+
+Both header files and implementation files can be compiled with a C++
+compiler (at least, that's a stated goal, and breakage will be treated
+as a bug).
+
+You need the following files in your source tree, or in a directory
+in your include path (e.g. in libev/ when using -Ilibev):
+
+ ev.h
+ ev.c
+ ev_vars.h
+ ev_wrap.h
+
+ ev_win32.c required on win32 platforms only
+
+ ev_select.c only when select backend is enabled
+ ev_poll.c only when poll backend is enabled
+ ev_epoll.c only when the epoll backend is enabled
+ ev_linuxaio.c only when the linux aio backend is enabled
+ ev_iouring.c only when the linux io_uring backend is enabled
+ ev_kqueue.c only when the kqueue backend is enabled
+ ev_port.c only when the solaris port backend is enabled
+
+F<ev.c> includes the backend files directly when enabled, so you only need
+to compile this single file.
+
+=head3 LIBEVENT COMPATIBILITY API
+
+To include the libevent compatibility API, also include:
+
+ #include "event.c"
+
+in the file including F<ev.c>, and:
+
+ #include "event.h"
+
+in the files that want to use the libevent API. This also includes F<ev.h>.
+
+You need the following additional files for this:
+
+ event.h
+ event.c
+
+=head3 AUTOCONF SUPPORT
+
+Instead of using C<EV_STANDALONE=1> and providing your configuration in
+whatever way you want, you can also C<m4_include([libev.m4])> in your
+F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then
+include F<config.h> and configure itself accordingly.
+
+For this of course you need the m4 file:
+
+ libev.m4
+
+=head2 PREPROCESSOR SYMBOLS/MACROS
+
+Libev can be configured via a variety of preprocessor symbols you have to
+define before including (or compiling) any of its files. The default in
+the absence of autoconf is documented for every option.
+
+Symbols marked with "(h)" do not change the ABI, and can have different
+values when compiling libev vs. including F<ev.h>, so it is permissible
+to redefine them before including F<ev.h> without breaking compatibility
+to a compiled library. All other symbols change the ABI, which means all
+users of libev and the libev code itself must be compiled with compatible
+settings.
+
+=over 4
+
+=item EV_COMPAT3 (h)
+
+Backwards compatibility is a major concern for libev. This is why this
+release of libev comes with wrappers for the functions and symbols that
+have been renamed between libev version 3 and 4.
+
+You can disable these wrappers (to test compatibility with future
+versions) by defining C<EV_COMPAT3> to C<0> when compiling your
+sources. This has the additional advantage that you can drop the C<struct>
+from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
+typedef in that case.
+
+In some future version, the default for C<EV_COMPAT3> will become C<0>,
+and in some even more future version the compatibility code will be
+removed completely.
+
+=item EV_STANDALONE (h)
+
+Must always be C<1> if you do not use autoconf configuration, which
+keeps libev from including F<config.h>, and it also defines dummy
+implementations for some libevent functions (such as logging, which is not
+supported). It will also not define any of the structs usually found in
+F<event.h> that are not directly supported by the libev core alone.
+
+In standalone mode, libev will still try to automatically deduce the
+configuration, but has to be more conservative.
+
+=item EV_USE_FLOOR
+
+If defined to be C<1>, libev will use the C<floor ()> function for its
+periodic reschedule calculations, otherwise libev will fall back on a
+portable (slower) implementation. If you enable this, you usually have to
+link against libm or something equivalent. Enabling this when the C<floor>
+function is not available will fail, so the safe default is to not enable
+this.
+
+=item EV_USE_MONOTONIC
+
+If defined to be C<1>, libev will try to detect the availability of the
+monotonic clock option at both compile time and runtime. Otherwise no
+use of the monotonic clock option will be attempted. If you enable this,
+you usually have to link against librt or something similar. Enabling it
+when the functionality isn't available is safe, though, although you have
+to make sure you link against any libraries where the C<clock_gettime>
+function is hiding in (often F<-lrt>). See also C<EV_USE_CLOCK_SYSCALL>.
+
+=item EV_USE_REALTIME
+
+If defined to be C<1>, libev will try to detect the availability of the
+real-time clock option at compile time (and assume its availability
+at runtime if successful). Otherwise no use of the real-time clock
+option will be attempted. This effectively replaces C<gettimeofday>
+by C<clock_get (CLOCK_REALTIME, ...)> and will not normally affect
+correctness. See the note about libraries in the description of
+C<EV_USE_MONOTONIC>, though. Defaults to the opposite value of
+C<EV_USE_CLOCK_SYSCALL>.
+
+=item EV_USE_CLOCK_SYSCALL
+
+If defined to be C<1>, libev will try to use a direct syscall instead
+of calling the system-provided C<clock_gettime> function. This option
+exists because on GNU/Linux, C<clock_gettime> is in C<librt>, but C<librt>
+unconditionally pulls in C<libpthread>, slowing down single-threaded
+programs needlessly. Using a direct syscall is slightly slower (in
+theory), because no optimised vdso implementation can be used, but avoids
+the pthread dependency. Defaults to C<1> on GNU/Linux with glibc 2.x or
+higher, as it simplifies linking (no need for C<-lrt>).
+
+=item EV_USE_NANOSLEEP
+
+If defined to be C<1>, libev will assume that C<nanosleep ()> is available
+and will use it for delays. Otherwise it will use C<select ()>.
+
+=item EV_USE_EVENTFD
+
+If defined to be C<1>, then libev will assume that C<eventfd ()> is
+available and will probe for kernel support at runtime. This will improve
+C<ev_signal> and C<ev_async> performance and reduce resource consumption.
+If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
+2.7 or newer, otherwise disabled.
+
+=item EV_USE_SIGNALFD
+
+If defined to be C<1>, then libev will assume that C<signalfd ()> is
+available and will probe for kernel support at runtime. This enables
+the use of EVFLAG_SIGNALFD for faster and simpler signal handling. If
+undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
+2.7 or newer, otherwise disabled.
+
+=item EV_USE_TIMERFD
+
+If defined to be C<1>, then libev will assume that C<timerfd ()> is
+available and will probe for kernel support at runtime. This allows
+libev to detect time jumps accurately. If undefined, it will be enabled
+if the headers indicate GNU/Linux + Glibc 2.8 or newer and define
+C<TFD_TIMER_CANCEL_ON_SET>, otherwise disabled.
+
+=item EV_USE_EVENTFD
+
+If defined to be C<1>, then libev will assume that C<eventfd ()> is
+available and will probe for kernel support at runtime. This will improve
+C<ev_signal> and C<ev_async> performance and reduce resource consumption.
+If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
+2.7 or newer, otherwise disabled.
+
+=item EV_USE_SELECT
+
+If undefined or defined to be C<1>, libev will compile in support for the
+C<select>(2) backend. No attempt at auto-detection will be done: if no
+other method takes over, select will be it. Otherwise the select backend
+will not be compiled in.
+
+=item EV_SELECT_USE_FD_SET
+
+If defined to C<1>, then the select backend will use the system C<fd_set>
+structure. This is useful if libev doesn't compile due to a missing
+C<NFDBITS> or C<fd_mask> definition or it mis-guesses the bitset layout
+on exotic systems. This usually limits the range of file descriptors to
+some low limit such as 1024 or might have other limitations (winsocket
+only allows 64 sockets). The C<FD_SETSIZE> macro, set before compilation,
+configures the maximum size of the C<fd_set>.
+
+=item EV_SELECT_IS_WINSOCKET
+
+When defined to C<1>, the select backend will assume that
+select/socket/connect etc. don't understand file descriptors but
+wants osf handles on win32 (this is the case when the select to
+be used is the winsock select). This means that it will call
+C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise,
+it is assumed that all these functions actually work on fds, even
+on win32. Should not be defined on non-win32 platforms.
+
+=item EV_FD_TO_WIN32_HANDLE(fd)
+
+If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map
+file descriptors to socket handles. When not defining this symbol (the
+default), then libev will call C<_get_osfhandle>, which is usually
+correct. In some cases, programs use their own file descriptor management,
+in which case they can provide this function to map fds to socket handles.
+
+=item EV_WIN32_HANDLE_TO_FD(handle)
+
+If C<EV_SELECT_IS_WINSOCKET> then libev maps handles to file descriptors
+using the standard C<_open_osfhandle> function. For programs implementing
+their own fd to handle mapping, overwriting this function makes it easier
+to do so. This can be done by defining this macro to an appropriate value.
+
+=item EV_WIN32_CLOSE_FD(fd)
+
+If programs implement their own fd to handle mapping on win32, then this
+macro can be used to override the C<close> function, useful to unregister
+file descriptors again. Note that the replacement function has to close
+the underlying OS handle.
+
+=item EV_USE_WSASOCKET
+
+If defined to be C<1>, libev will use C<WSASocket> to create its internal
+communication socket, which works better in some environments. Otherwise,
+the normal C<socket> function will be used, which works better in other
+environments.
+
+=item EV_USE_POLL
+
+If defined to be C<1>, libev will compile in support for the C<poll>(2)
+backend. Otherwise it will be enabled on non-win32 platforms. It
+takes precedence over select.
+
+=item EV_USE_EPOLL
+
+If defined to be C<1>, libev will compile in support for the Linux
+C<epoll>(7) backend. Its availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for GNU/Linux systems. If undefined, it will be enabled if the
+headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
+
+=item EV_USE_LINUXAIO
+
+If defined to be C<1>, libev will compile in support for the Linux aio
+backend (C<EV_USE_EPOLL> must also be enabled). If undefined, it will be
+enabled on linux, otherwise disabled.
+
+=item EV_USE_IOURING
+
+If defined to be C<1>, libev will compile in support for the Linux
+io_uring backend (C<EV_USE_EPOLL> must also be enabled). Due to it's
+current limitations it has to be requested explicitly. If undefined, it
+will be enabled on linux, otherwise disabled.
+
+=item EV_USE_KQUEUE
+
+If defined to be C<1>, libev will compile in support for the BSD style
+C<kqueue>(2) backend. Its actual availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for BSD and BSD-like systems, although on most BSDs kqueue only
+supports some types of fds correctly (the only platform we found that
+supports ptys for example was NetBSD), so kqueue might be compiled in, but
+not be used unless explicitly requested. The best way to use it is to find
+out whether kqueue supports your type of fd properly and use an embedded
+kqueue loop.
+
+=item EV_USE_PORT
+
+If defined to be C<1>, libev will compile in support for the Solaris
+10 port style backend. Its availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for Solaris 10 systems.
+
+=item EV_USE_DEVPOLL
+
+Reserved for future expansion, works like the USE symbols above.
+
+=item EV_USE_INOTIFY
+
+If defined to be C<1>, libev will compile in support for the Linux inotify
+interface to speed up C<ev_stat> watchers. Its actual availability will
+be detected at runtime. If undefined, it will be enabled if the headers
+indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
+
+=item EV_NO_SMP
+
+If defined to be C<1>, libev will assume that memory is always coherent
+between threads, that is, threads can be used, but threads never run on
+different cpus (or different cpu cores). This reduces dependencies
+and makes libev faster.
+
+=item EV_NO_THREADS
+
+If defined to be C<1>, libev will assume that it will never be called from
+different threads (that includes signal handlers), which is a stronger
+assumption than C<EV_NO_SMP>, above. This reduces dependencies and makes
+libev faster.
+
+=item EV_ATOMIC_T
+
+Libev requires an integer type (suitable for storing C<0> or C<1>) whose
+access is atomic with respect to other threads or signal contexts. No
+such type is easily found in the C language, so you can provide your own
+type that you know is safe for your purposes. It is used both for signal
+handler "locking" as well as for signal and thread safety in C<ev_async>
+watchers.
+
+In the absence of this define, libev will use C<sig_atomic_t volatile>
+(from F<signal.h>), which is usually good enough on most platforms.
+
+=item EV_H (h)
+
+The name of the F<ev.h> header file used to include it. The default if
+undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
+used to virtually rename the F<ev.h> header file in case of conflicts.
+
+=item EV_CONFIG_H (h)
+
+If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
+F<ev.c>'s idea of where to find the F<config.h> file, similarly to
+C<EV_H>, above.
+
+=item EV_EVENT_H (h)
+
+Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
+of how the F<event.h> header can be found, the default is C<"event.h">.
+
+=item EV_PROTOTYPES (h)
+
+If defined to be C<0>, then F<ev.h> will not define any function
+prototypes, but still define all the structs and other symbols. This is
+occasionally useful if you want to provide your own wrapper functions
+around libev functions.
+
+=item EV_MULTIPLICITY
+
+If undefined or defined to C<1>, then all event-loop-specific functions
+will have the C<struct ev_loop *> as first argument, and you can create
+additional independent event loops. Otherwise there will be no support
+for multiple event loops and there is no first event loop pointer
+argument. Instead, all functions act on the single default loop.
+
+Note that C<EV_DEFAULT> and C<EV_DEFAULT_> will no longer provide a
+default loop when multiplicity is switched off - you always have to
+initialise the loop manually in this case.
+
+=item EV_MINPRI
+
+=item EV_MAXPRI
+
+The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to
+C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can
+provide for more priorities by overriding those symbols (usually defined
+to be C<-2> and C<2>, respectively).
+
+When doing priority-based operations, libev usually has to linearly search
+all the priorities, so having many of them (hundreds) uses a lot of space
+and time, so using the defaults of five priorities (-2 .. +2) is usually
+fine.
+
+If your embedding application does not need any priorities, defining these
+both to C<0> will save some memory and CPU.
+
+=item EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE,
+EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
+EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
+
+If undefined or defined to be C<1> (and the platform supports it), then
+the respective watcher type is supported. If defined to be C<0>, then it
+is not. Disabling watcher types mainly saves code size.
+
+=item EV_FEATURES
+
+If you need to shave off some kilobytes of code at the expense of some
+speed (but with the full API), you can define this symbol to request
+certain subsets of functionality. The default is to enable all features
+that can be enabled on the platform.
+
+A typical way to use this symbol is to define it to C<0> (or to a bitset
+with some broad features you want) and then selectively re-enable
+additional parts you want, for example if you want everything minimal,
+but multiple event loop support, async and child watchers and the poll
+backend, use this:
+
+ #define EV_FEATURES 0
+ #define EV_MULTIPLICITY 1
+ #define EV_USE_POLL 1
+ #define EV_CHILD_ENABLE 1
+ #define EV_ASYNC_ENABLE 1
+
+The actual value is a bitset, it can be a combination of the following
+values (by default, all of these are enabled):
+
+=over 4
+
+=item C<1> - faster/larger code
+
+Use larger code to speed up some operations.
+
+Currently this is used to override some inlining decisions (enlarging the
+code size by roughly 30% on amd64).
+
+When optimising for size, use of compiler flags such as C<-Os> with
+gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
+assertions.
+
+The default is off when C<__OPTIMIZE_SIZE__> is defined by your compiler
+(e.g. gcc with C<-Os>).
+
+=item C<2> - faster/larger data structures
+
+Replaces the small 2-heap for timer management by a faster 4-heap, larger
+hash table sizes and so on. This will usually further increase code size
+and can additionally have an effect on the size of data structures at
+runtime.
+
+The default is off when C<__OPTIMIZE_SIZE__> is defined by your compiler
+(e.g. gcc with C<-Os>).
+
+=item C<4> - full API configuration
+
+This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
+enables multiplicity (C<EV_MULTIPLICITY>=1).
+
+=item C<8> - full API
+
+This enables a lot of the "lesser used" API functions. See C<ev.h> for
+details on which parts of the API are still available without this
+feature, and do not complain if this subset changes over time.
+
+=item C<16> - enable all optional watcher types
+
+Enables all optional watcher types. If you want to selectively enable
+only some watcher types other than I/O and timers (e.g. prepare,
+embed, async, child...) you can enable them manually by defining
+C<EV_watchertype_ENABLE> to C<1> instead.
+
+=item C<32> - enable all backends
+
+This enables all backends - without this feature, you need to enable at
+least one backend manually (C<EV_USE_SELECT> is a good choice).
+
+=item C<64> - enable OS-specific "helper" APIs
+
+Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
+default.
+
+=back
+
+Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
+reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
+code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
+watchers, timers and monotonic clock support.
+
+With an intelligent-enough linker (gcc+binutils are intelligent enough
+when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
+your program might be left out as well - a binary starting a timer and an
+I/O watcher then might come out at only 5Kb.
+
+=item EV_API_STATIC
+
+If this symbol is defined (by default it is not), then all identifiers
+will have static linkage. This means that libev will not export any
+identifiers, and you cannot link against libev anymore. This can be useful
+when you embed libev, only want to use libev functions in a single file,
+and do not want its identifiers to be visible.
+
+To use this, define C<EV_API_STATIC> and include F<ev.c> in the file that
+wants to use libev.
+
+This option only works when libev is compiled with a C compiler, as C++
+doesn't support the required declaration syntax.
+
+=item EV_AVOID_STDIO
+
+If this is set to C<1> at compiletime, then libev will avoid using stdio
+functions (printf, scanf, perror etc.). This will increase the code size
+somewhat, but if your program doesn't otherwise depend on stdio and your
+libc allows it, this avoids linking in the stdio library which is quite
+big.
+
+Note that error messages might become less precise when this option is
+enabled.
+
+=item EV_NSIG
+
+The highest supported signal number, +1 (or, the number of
+signals): Normally, libev tries to deduce the maximum number of signals
+automatically, but sometimes this fails, in which case it can be
+specified. Also, using a lower number than detected (C<32> should be
+good for about any system in existence) can save some memory, as libev
+statically allocates some 12-24 bytes per signal number.
+
+=item EV_PID_HASHSIZE
+
+C<ev_child> watchers use a small hash table to distribute workload by
+pid. The default size is C<16> (or C<1> with C<EV_FEATURES> disabled),
+usually more than enough. If you need to manage thousands of children you
+might want to increase this value (I<must> be a power of two).
+
+=item EV_INOTIFY_HASHSIZE
+
+C<ev_stat> watchers use a small hash table to distribute workload by
+inotify watch id. The default size is C<16> (or C<1> with C<EV_FEATURES>
+disabled), usually more than enough. If you need to manage thousands of
+C<ev_stat> watchers you might want to increase this value (I<must> be a
+power of two).
+
+=item EV_USE_4HEAP
+
+Heaps are not very cache-efficient. To improve the cache-efficiency of the
+timer and periodics heaps, libev uses a 4-heap when this symbol is defined
+to C<1>. The 4-heap uses more complicated (longer) code but has noticeably
+faster performance with many (thousands) of watchers.
+
+The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
+will be C<0>.
+
+=item EV_HEAP_CACHE_AT
+
+Heaps are not very cache-efficient. To improve the cache-efficiency of the
+timer and periodics heaps, libev can cache the timestamp (I<at>) within
+the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
+which uses 8-12 bytes more per watcher and a few hundred bytes more code,
+but avoids random read accesses on heap changes. This improves performance
+noticeably with many (hundreds) of watchers.
+
+The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
+will be C<0>.
+
+=item EV_VERIFY
+
+Controls how much internal verification (see C<ev_verify ()>) will
+be done: If set to C<0>, no internal verification code will be compiled
+in. If set to C<1>, then verification code will be compiled in, but not
+called. If set to C<2>, then the internal verification code will be
+called once per loop, which can slow down libev. If set to C<3>, then the
+verification code will be called very frequently, which will slow down
+libev considerably.
+
+Verification errors are reported via C's C<assert> mechanism, so if you
+disable that (e.g. by defining C<NDEBUG>) then no errors will be reported.
+
+The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
+will be C<0>.
+
+=item EV_COMMON
+
+By default, all watchers have a C<void *data> member. By redefining
+this macro to something else you can include more and other types of
+members. You have to define it each time you include one of the files,
+though, and it must be identical each time.
+
+For example, the perl EV module uses something like this:
+
+ #define EV_COMMON \
+ SV *self; /* contains this struct */ \
+ SV *cb_sv, *fh /* note no trailing ";" */
+
+=item EV_CB_DECLARE (type)
+
+=item EV_CB_INVOKE (watcher, revents)
+
+=item ev_set_cb (ev, cb)
+
+Can be used to change the callback member declaration in each watcher,
+and the way callbacks are invoked and set. Must expand to a struct member
+definition and a statement, respectively. See the F<ev.h> header file for
+their default definitions. One possible use for overriding these is to
+avoid the C<struct ev_loop *> as first argument in all cases, or to use
+method calls instead of plain function calls in C++.
+
+=back
+
+=head2 EXPORTED API SYMBOLS
+
+If you need to re-export the API (e.g. via a DLL) and you need a list of
+exported symbols, you can use the provided F<Symbol.*> files which list
+all public symbols, one per line:
+
+ Symbols.ev for libev proper
+ Symbols.event for the libevent emulation
+
+This can also be used to rename all public symbols to avoid clashes with
+multiple versions of libev linked together (which is obviously bad in
+itself, but sometimes it is inconvenient to avoid this).
+
+A sed command like this will create wrapper C<#define>'s that you need to
+include before including F<ev.h>:
+
+ <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h
+
+This would create a file F<wrap.h> which essentially looks like this:
+
+ #define ev_backend myprefix_ev_backend
+ #define ev_check_start myprefix_ev_check_start
+ #define ev_check_stop myprefix_ev_check_stop
+ ...
+
+=head2 EXAMPLES
+
+For a real-world example of a program the includes libev
+verbatim, you can have a look at the EV perl module
+(L<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
+the F<libev/> subdirectory and includes them in the F<EV/EVAPI.h> (public
+interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file
+will be compiled. It is pretty complex because it provides its own header
+file.
+
+The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
+that everybody includes and which overrides some configure choices:
+
+ #define EV_FEATURES 8
+ #define EV_USE_SELECT 1
+ #define EV_PREPARE_ENABLE 1
+ #define EV_IDLE_ENABLE 1
+ #define EV_SIGNAL_ENABLE 1
+ #define EV_CHILD_ENABLE 1
+ #define EV_USE_STDEXCEPT 0
+ #define EV_CONFIG_H <config.h>
+
+ #include "ev++.h"
+
+And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
+
+ #include "ev_cpp.h"
+ #include "ev.c"
+
+=head1 INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT
+
+=head2 THREADS AND COROUTINES
+
+=head3 THREADS
+
+All libev functions are reentrant and thread-safe unless explicitly
+documented otherwise, but libev implements no locking itself. This means
+that you can use as many loops as you want in parallel, as long as there
+are no concurrent calls into any libev function with the same loop
+parameter (C<ev_default_*> calls have an implicit default loop parameter,
+of course): libev guarantees that different event loops share no data
+structures that need any locking.
+
+Or to put it differently: calls with different loop parameters can be done
+concurrently from multiple threads, calls with the same loop parameter
+must be done serially (but can be done from different threads, as long as
+only one thread ever is inside a call at any point in time, e.g. by using
+a mutex per loop).
+
+Specifically to support threads (and signal handlers), libev implements
+so-called C<ev_async> watchers, which allow some limited form of
+concurrency on the same event loop, namely waking it up "from the
+outside".
+
+If you want to know which design (one loop, locking, or multiple loops
+without or something else still) is best for your problem, then I cannot
+help you, but here is some generic advice:
+
+=over 4
+
+=item * most applications have a main thread: use the default libev loop
+in that thread, or create a separate thread running only the default loop.
+
+This helps integrating other libraries or software modules that use libev
+themselves and don't care/know about threading.
+
+=item * one loop per thread is usually a good model.
+
+Doing this is almost never wrong, sometimes a better-performance model
+exists, but it is always a good start.
+
+=item * other models exist, such as the leader/follower pattern, where one
+loop is handed through multiple threads in a kind of round-robin fashion.
+
+Choosing a model is hard - look around, learn, know that usually you can do
+better than you currently do :-)
+
+=item * often you need to talk to some other thread which blocks in the
+event loop.
+
+C<ev_async> watchers can be used to wake them up from other threads safely
+(or from signal contexts...).
+
+An example use would be to communicate signals or other events that only
+work in the default loop by registering the signal watcher with the
+default loop and triggering an C<ev_async> watcher from the default loop
+watcher callback into the event loop interested in the signal.
+
+=back
+
+See also L</THREAD LOCKING EXAMPLE>.
+
+=head3 COROUTINES
+
+Libev is very accommodating to coroutines ("cooperative threads"):
+libev fully supports nesting calls to its functions from different
+coroutines (e.g. you can call C<ev_run> on the same loop from two
+different coroutines, and switch freely between both coroutines running
+the loop, as long as you don't confuse yourself). The only exception is
+that you must not do this from C<ev_periodic> reschedule callbacks.
+
+Care has been taken to ensure that libev does not keep local state inside
+C<ev_run>, and other calls do not usually allow for coroutine switches as
+they do not call any callbacks.
+
+=head2 COMPILER WARNINGS
+
+Depending on your compiler and compiler settings, you might get no or a
+lot of warnings when compiling libev code. Some people are apparently
+scared by this.
+
+However, these are unavoidable for many reasons. For one, each compiler
+has different warnings, and each user has different tastes regarding
+warning options. "Warn-free" code therefore cannot be a goal except when
+targeting a specific compiler and compiler-version.
+
+Another reason is that some compiler warnings require elaborate
+workarounds, or other changes to the code that make it less clear and less
+maintainable.
+
+And of course, some compiler warnings are just plain stupid, or simply
+wrong (because they don't actually warn about the condition their message
+seems to warn about). For example, certain older gcc versions had some
+warnings that resulted in an extreme number of false positives. These have
+been fixed, but some people still insist on making code warn-free with
+such buggy versions.
+
+While libev is written to generate as few warnings as possible,
+"warn-free" code is not a goal, and it is recommended not to build libev
+with any compiler warnings enabled unless you are prepared to cope with
+them (e.g. by ignoring them). Remember that warnings are just that:
+warnings, not errors, or proof of bugs.
+
+
+=head2 VALGRIND
+
+Valgrind has a special section here because it is a popular tool that is
+highly useful. Unfortunately, valgrind reports are very hard to interpret.
+
+If you think you found a bug (memory leak, uninitialised data access etc.)
+in libev, then check twice: If valgrind reports something like:
+
+ ==2274== definitely lost: 0 bytes in 0 blocks.
+ ==2274== possibly lost: 0 bytes in 0 blocks.
+ ==2274== still reachable: 256 bytes in 1 blocks.
+
+Then there is no memory leak, just as memory accounted to global variables
+is not a memleak - the memory is still being referenced, and didn't leak.
+
+Similarly, under some circumstances, valgrind might report kernel bugs
+as if it were a bug in libev (e.g. in realloc or in the poll backend,
+although an acceptable workaround has been found here), or it might be
+confused.
+
+Keep in mind that valgrind is a very good tool, but only a tool. Don't
+make it into some kind of religion.
+
+If you are unsure about something, feel free to contact the mailing list
+with the full valgrind report and an explanation on why you think this
+is a bug in libev (best check the archives, too :). However, don't be
+annoyed when you get a brisk "this is no bug" answer and take the chance
+of learning how to interpret valgrind properly.
+
+If you need, for some reason, empty reports from valgrind for your project
+I suggest using suppression lists.
+
+
+=head1 PORTABILITY NOTES
+
+=head2 GNU/LINUX 32 BIT LIMITATIONS
+
+GNU/Linux is the only common platform that supports 64 bit file/large file
+interfaces but I<disables> them by default.
+
+That means that libev compiled in the default environment doesn't support
+files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
+
+Unfortunately, many programs try to work around this GNU/Linux issue
+by enabling the large file API, which makes them incompatible with the
+standard libev compiled for their system.
+
+Likewise, libev cannot enable the large file API itself as this would
+suddenly make it incompatible to the default compile time environment,
+i.e. all programs not using special compile switches.
+
+=head2 OS/X AND DARWIN BUGS
+
+The whole thing is a bug if you ask me - basically any system interface
+you touch is broken, whether it is locales, poll, kqueue or even the
+OpenGL drivers.
+
+=head3 C<kqueue> is buggy
+
+The kqueue syscall is broken in all known versions - most versions support
+only sockets, many support pipes.
+
+Libev tries to work around this by not using C<kqueue> by default on this
+rotten platform, but of course you can still ask for it when creating a
+loop - embedding a socket-only kqueue loop into a select-based one is
+probably going to work well.
+
+=head3 C<poll> is buggy
+
+Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
+implementation by something calling C<kqueue> internally around the 10.5.6
+release, so now C<kqueue> I<and> C<poll> are broken.
+
+Libev tries to work around this by not using C<poll> by default on
+this rotten platform, but of course you can still ask for it when creating
+a loop.
+
+=head3 C<select> is buggy
+
+All that's left is C<select>, and of course Apple found a way to fuck this
+one up as well: On OS/X, C<select> actively limits the number of file
+descriptors you can pass in to 1024 - your program suddenly crashes when
+you use more.
+
+There is an undocumented "workaround" for this - defining
+C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
+work on OS/X.
+
+=head2 SOLARIS PROBLEMS AND WORKAROUNDS
+
+=head3 C<errno> reentrancy
+
+The default compile environment on Solaris is unfortunately so
+thread-unsafe that you can't even use components/libraries compiled
+without C<-D_REENTRANT> in a threaded program, which, of course, isn't
+defined by default. A valid, if stupid, implementation choice.
+
+If you want to use libev in threaded environments you have to make sure
+it's compiled with C<_REENTRANT> defined.
+
+=head3 Event port backend
+
+The scalable event interface for Solaris is called "event
+ports". Unfortunately, this mechanism is very buggy in all major
+releases. If you run into high CPU usage, your program freezes or you get
+a large number of spurious wakeups, make sure you have all the relevant
+and latest kernel patches applied. No, I don't know which ones, but there
+are multiple ones to apply, and afterwards, event ports actually work
+great.
+
+If you can't get it to work, you can try running the program by setting
+the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
+C<select> backends.
+
+=head2 AIX POLL BUG
+
+AIX unfortunately has a broken C<poll.h> header. Libev works around
+this by trying to avoid the poll backend altogether (i.e. it's not even
+compiled in), which normally isn't a big problem as C<select> works fine
+with large bitsets on AIX, and AIX is dead anyway.
+
+=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
+
+=head3 General issues
+
+Win32 doesn't support any of the standards (e.g. POSIX) that libev
+requires, and its I/O model is fundamentally incompatible with the POSIX
+model. Libev still offers limited functionality on this platform in
+the form of the C<EVBACKEND_SELECT> backend, and only supports socket
+descriptors. This only applies when using Win32 natively, not when using
+e.g. cygwin. Actually, it only applies to the microsofts own compilers,
+as every compiler comes with a slightly differently broken/incompatible
+environment.
+
+Lifting these limitations would basically require the full
+re-implementation of the I/O system. If you are into this kind of thing,
+then note that glib does exactly that for you in a very portable way (note
+also that glib is the slowest event library known to man).
+
+There is no supported compilation method available on windows except
+embedding it into other applications.
+
+Sensible signal handling is officially unsupported by Microsoft - libev
+tries its best, but under most conditions, signals will simply not work.
+
+Not a libev limitation but worth mentioning: windows apparently doesn't
+accept large writes: instead of resulting in a partial write, windows will
+either accept everything or return C<ENOBUFS> if the buffer is too large,
+so make sure you only write small amounts into your sockets (less than a
+megabyte seems safe, but this apparently depends on the amount of memory
+available).
+
+Due to the many, low, and arbitrary limits on the win32 platform and
+the abysmal performance of winsockets, using a large number of sockets
+is not recommended (and not reasonable). If your program needs to use
+more than a hundred or so sockets, then likely it needs to use a totally
+different implementation for windows, as libev offers the POSIX readiness
+notification model, which cannot be implemented efficiently on windows
+(due to Microsoft monopoly games).
+
+A typical way to use libev under windows is to embed it (see the embedding
+section for details) and use the following F<evwrap.h> header file instead
+of F<ev.h>:
+
+ #define EV_STANDALONE /* keeps ev from requiring config.h */
+ #define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */
+
+ #include "ev.h"
+
+And compile the following F<evwrap.c> file into your project (make sure
+you do I<not> compile the F<ev.c> or any other embedded source files!):
+
+ #include "evwrap.h"
+ #include "ev.c"
+
+=head3 The winsocket C<select> function
+
+The winsocket C<select> function doesn't follow POSIX in that it
+requires socket I<handles> and not socket I<file descriptors> (it is
+also extremely buggy). This makes select very inefficient, and also
+requires a mapping from file descriptors to socket handles (the Microsoft
+C runtime provides the function C<_open_osfhandle> for this). See the
+discussion of the C<EV_SELECT_USE_FD_SET>, C<EV_SELECT_IS_WINSOCKET> and
+C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info.
+
+The configuration for a "naked" win32 using the Microsoft runtime
+libraries and raw winsocket select is:
+
+ #define EV_USE_SELECT 1
+ #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
+
+Note that winsockets handling of fd sets is O(n), so you can easily get a
+complexity in the O(n²) range when using win32.
+
+=head3 Limited number of file descriptors
+
+Windows has numerous arbitrary (and low) limits on things.
+
+Early versions of winsocket's select only supported waiting for a maximum
+of C<64> handles (probably owning to the fact that all windows kernels
+can only wait for C<64> things at the same time internally; Microsoft
+recommends spawning a chain of threads and wait for 63 handles and the
+previous thread in each. Sounds great!).
+
+Newer versions support more handles, but you need to define C<FD_SETSIZE>
+to some high number (e.g. C<2048>) before compiling the winsocket select
+call (which might be in libev or elsewhere, for example, perl and many
+other interpreters do their own select emulation on windows).
+
+Another limit is the number of file descriptors in the Microsoft runtime
+libraries, which by default is C<64> (there must be a hidden I<64>
+fetish or something like this inside Microsoft). You can increase this
+by calling C<_setmaxstdio>, which can increase this limit to C<2048>
+(another arbitrary limit), but is broken in many versions of the Microsoft
+runtime libraries. This might get you to about C<512> or C<2048> sockets
+(depending on windows version and/or the phase of the moon). To get more,
+you need to wrap all I/O functions and provide your own fd management, but
+the cost of calling select (O(n²)) will likely make this unworkable.
+
+=head2 PORTABILITY REQUIREMENTS
+
+In addition to a working ISO-C implementation and of course the
+backend-specific APIs, libev relies on a few additional extensions:
+
+=over 4
+
+=item C<void (*)(ev_watcher_type *, int revents)> must have compatible
+calling conventions regardless of C<ev_watcher_type *>.
+
+Libev assumes not only that all watcher pointers have the same internal
+structure (guaranteed by POSIX but not by ISO C for example), but it also
+assumes that the same (machine) code can be used to call any watcher
+callback: The watcher callbacks have different type signatures, but libev
+calls them using an C<ev_watcher *> internally.
+
+=item null pointers and integer zero are represented by 0 bytes
+
+Libev uses C<memset> to initialise structs and arrays to C<0> bytes, and
+relies on this setting pointers and integers to null.
+
+=item pointer accesses must be thread-atomic
+
+Accessing a pointer value must be atomic, it must both be readable and
+writable in one piece - this is the case on all current architectures.
+
+=item C<sig_atomic_t volatile> must be thread-atomic as well
+
+The type C<sig_atomic_t volatile> (or whatever is defined as
+C<EV_ATOMIC_T>) must be atomic with respect to accesses from different
+threads. This is not part of the specification for C<sig_atomic_t>, but is
+believed to be sufficiently portable.
+
+=item C<sigprocmask> must work in a threaded environment
+
+Libev uses C<sigprocmask> to temporarily block signals. This is not
+allowed in a threaded program (C<pthread_sigmask> has to be used). Typical
+pthread implementations will either allow C<sigprocmask> in the "main
+thread" or will block signals process-wide, both behaviours would
+be compatible with libev. Interaction between C<sigprocmask> and
+C<pthread_sigmask> could complicate things, however.
+
+The most portable way to handle signals is to block signals in all threads
+except the initial one, and run the signal handling loop in the initial
+thread as well.
+
+=item C<long> must be large enough for common memory allocation sizes
+
+To improve portability and simplify its API, libev uses C<long> internally
+instead of C<size_t> when allocating its data structures. On non-POSIX
+systems (Microsoft...) this might be unexpectedly low, but is still at
+least 31 bits everywhere, which is enough for hundreds of millions of
+watchers.
+
+=item C<double> must hold a time value in seconds with enough accuracy
+
+The type C<double> is used to represent timestamps. It is required to
+have at least 51 bits of mantissa (and 9 bits of exponent), which is
+good enough for at least into the year 4000 with millisecond accuracy
+(the design goal for libev). This requirement is overfulfilled by
+implementations using IEEE 754, which is basically all existing ones.
+
+With IEEE 754 doubles, you get microsecond accuracy until at least the
+year 2255 (and millisecond accuracy till the year 287396 - by then, libev
+is either obsolete or somebody patched it to use C<long double> or
+something like that, just kidding).
+
+=back
+
+If you know of other additional requirements drop me a note.
+
+
+=head1 ALGORITHMIC COMPLEXITIES
+
+In this section the complexities of (many of) the algorithms used inside
+libev will be documented. For complexity discussions about backends see
+the documentation for C<ev_default_init>.
+
+All of the following are about amortised time: If an array needs to be
+extended, libev needs to realloc and move the whole array, but this
+happens asymptotically rarer with higher number of elements, so O(1) might
+mean that libev does a lengthy realloc operation in rare cases, but on
+average it is much faster and asymptotically approaches constant time.
+
+=over 4
+
+=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
+
+This means that, when you have a watcher that triggers in one hour and
+there are 100 watchers that would trigger before that, then inserting will
+have to skip roughly seven (C<ld 100>) of these watchers.
+
+=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)
+
+That means that changing a timer costs less than removing/adding them,
+as only the relative motion in the event queue has to be paid for.
+
+=item Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)
+
+These just add the watcher into an array or at the head of a list.
+
+=item Stopping check/prepare/idle/fork/async watchers: O(1)
+
+=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
+
+These watchers are stored in lists, so they need to be walked to find the
+correct watcher to remove. The lists are usually short (you don't usually
+have many watchers waiting for the same fd or signal: one is typical, two
+is rare).
+
+=item Finding the next timer in each loop iteration: O(1)
+
+By virtue of using a binary or 4-heap, the next timer is always found at a
+fixed position in the storage array.
+
+=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
+
+A change means an I/O watcher gets started or stopped, which requires
+libev to recalculate its status (and possibly tell the kernel, depending
+on backend and whether C<ev_io_set> was used).
+
+=item Activating one watcher (putting it into the pending state): O(1)
+
+=item Priority handling: O(number_of_priorities)
+
+Priorities are implemented by allocating some space for each
+priority. When doing priority-based operations, libev usually has to
+linearly search all the priorities, but starting/stopping and activating
+watchers becomes O(1) with respect to priority handling.
+
+=item Sending an ev_async: O(1)
+
+=item Processing ev_async_send: O(number_of_async_watchers)
+
+=item Processing signals: O(max_signal_number)
+
+Sending involves a system call I<iff> there were no other C<ev_async_send>
+calls in the current loop iteration and the loop is currently
+blocked. Checking for async and signal events involves iterating over all
+running async watchers or all signal numbers.
+
+=back
+
+
+=head1 PORTING FROM LIBEV 3.X TO 4.X
+
+The major version 4 introduced some incompatible changes to the API.
+
+At the moment, the C<ev.h> header file provides compatibility definitions
+for all changes, so most programs should still compile. The compatibility
+layer might be removed in later versions of libev, so better update to the
+new API early than late.
+
+=over 4
+
+=item C<EV_COMPAT3> backwards compatibility mechanism
+
+The backward compatibility mechanism can be controlled by
+C<EV_COMPAT3>. See L</"PREPROCESSOR SYMBOLS/MACROS"> in the L</EMBEDDING>
+section.
+
+=item C<ev_default_destroy> and C<ev_default_fork> have been removed
+
+These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
+
+ ev_loop_destroy (EV_DEFAULT_UC);
+ ev_loop_fork (EV_DEFAULT);
+
+=item function/symbol renames
+
+A number of functions and symbols have been renamed:
+
+ ev_loop => ev_run
+ EVLOOP_NONBLOCK => EVRUN_NOWAIT
+ EVLOOP_ONESHOT => EVRUN_ONCE
+
+ ev_unloop => ev_break
+ EVUNLOOP_CANCEL => EVBREAK_CANCEL
+ EVUNLOOP_ONE => EVBREAK_ONE
+ EVUNLOOP_ALL => EVBREAK_ALL
+
+ EV_TIMEOUT => EV_TIMER
+
+ ev_loop_count => ev_iteration
+ ev_loop_depth => ev_depth
+ ev_loop_verify => ev_verify
+
+Most functions working on C<struct ev_loop> objects don't have an
+C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
+associated constants have been renamed to not collide with the C<struct
+ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
+as all other watcher types. Note that C<ev_loop_fork> is still called
+C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
+typedef.
+
+=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
+
+The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
+mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
+and work, but the library code will of course be larger.
+
+=back
+
+
+=head1 GLOSSARY
+
+=over 4
+
+=item active
+
+A watcher is active as long as it has been started and not yet stopped.
+See L</WATCHER STATES> for details.
+
+=item application
+
+In this document, an application is whatever is using libev.
+
+=item backend
+
+The part of the code dealing with the operating system interfaces.
+
+=item callback
+
+The address of a function that is called when some event has been
+detected. Callbacks are being passed the event loop, the watcher that
+received the event, and the actual event bitset.
+
+=item callback/watcher invocation
+
+The act of calling the callback associated with a watcher.
+
+=item event
+
+A change of state of some external event, such as data now being available
+for reading on a file descriptor, time having passed or simply not having
+any other events happening anymore.
+
+In libev, events are represented as single bits (such as C<EV_READ> or
+C<EV_TIMER>).
+
+=item event library
+
+A software package implementing an event model and loop.
+
+=item event loop
+
+An entity that handles and processes external events and converts them
+into callback invocations.
+
+=item event model
+
+The model used to describe how an event loop handles and processes
+watchers and events.
+
+=item pending
+
+A watcher is pending as soon as the corresponding event has been
+detected. See L</WATCHER STATES> for details.
+
+=item real time
+
+The physical time that is observed. It is apparently strictly monotonic :)
+
+=item wall-clock time
+
+The time and date as shown on clocks. Unlike real time, it can actually
+be wrong and jump forwards and backwards, e.g. when you adjust your
+clock.
+
+=item watcher
+
+A data structure that describes interest in certain events. Watchers need
+to be started (attached to an event loop) before they can receive events.
+
+=back
+
+=head1 AUTHOR
+
+Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
+Magnusson and Emanuele Giaquinta, and minor corrections by many others.
+
diff --git a/3rdparty/libev/ev_epoll.c b/3rdparty/libev/ev_epoll.c
new file mode 100644
index 0000000..58cfa68
--- /dev/null
+++ b/3rdparty/libev/ev_epoll.c
@@ -0,0 +1,298 @@
+/*
+ * libev epoll fd activity backend
+ *
+ * Copyright (c) 2007,2008,2009,2010,2011,2016,2017,2019 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+/*
+ * general notes about epoll:
+ *
+ * a) epoll silently removes fds from the fd set. as nothing tells us
+ * that an fd has been removed otherwise, we have to continually
+ * "rearm" fds that we suspect *might* have changed (same
+ * problem with kqueue, but much less costly there).
+ * b) the fact that ADD != MOD creates a lot of extra syscalls due to a)
+ * and seems not to have any advantage.
+ * c) the inability to handle fork or file descriptors (think dup)
+ * limits the applicability over poll, so this is not a generic
+ * poll replacement.
+ * d) epoll doesn't work the same as select with many file descriptors
+ * (such as files). while not critical, no other advanced interface
+ * seems to share this (rather non-unixy) limitation.
+ * e) epoll claims to be embeddable, but in practise you never get
+ * a ready event for the epoll fd (broken: <=2.6.26, working: >=2.6.32).
+ * f) epoll_ctl returning EPERM means the fd is always ready.
+ *
+ * lots of "weird code" and complication handling in this file is due
+ * to these design problems with epoll, as we try very hard to avoid
+ * epoll_ctl syscalls for common usage patterns and handle the breakage
+ * ensuing from receiving events for closed and otherwise long gone
+ * file descriptors.
+ */
+
+#include <sys/epoll.h>
+
+#define EV_EMASK_EPERM 0x80
+
+static void
+epoll_modify (EV_P_ int fd, int oev, int nev)
+{
+ struct epoll_event ev;
+ unsigned char oldmask;
+
+ /*
+ * we handle EPOLL_CTL_DEL by ignoring it here
+ * on the assumption that the fd is gone anyways
+ * if that is wrong, we have to handle the spurious
+ * event in epoll_poll.
+ * if the fd is added again, we try to ADD it, and, if that
+ * fails, we assume it still has the same eventmask.
+ */
+ if (!nev)
+ return;
+
+ oldmask = anfds [fd].emask;
+ anfds [fd].emask = nev;
+
+ /* store the generation counter in the upper 32 bits, the fd in the lower 32 bits */
+ ev.data.u64 = (uint64_t)(uint32_t)fd
+ | ((uint64_t)(uint32_t)++anfds [fd].egen << 32);
+ ev.events = (nev & EV_READ ? EPOLLIN : 0)
+ | (nev & EV_WRITE ? EPOLLOUT : 0);
+
+ if (ecb_expect_true (!epoll_ctl (backend_fd, oev && oldmask != nev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev)))
+ return;
+
+ if (ecb_expect_true (errno == ENOENT))
+ {
+ /* if ENOENT then the fd went away, so try to do the right thing */
+ if (!nev)
+ goto dec_egen;
+
+ if (!epoll_ctl (backend_fd, EPOLL_CTL_ADD, fd, &ev))
+ return;
+ }
+ else if (ecb_expect_true (errno == EEXIST))
+ {
+ /* EEXIST means we ignored a previous DEL, but the fd is still active */
+ /* if the kernel mask is the same as the new mask, we assume it hasn't changed */
+ if (oldmask == nev)
+ goto dec_egen;
+
+ if (!epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev))
+ return;
+ }
+ else if (ecb_expect_true (errno == EPERM))
+ {
+ /* EPERM means the fd is always ready, but epoll is too snobbish */
+ /* to handle it, unlike select or poll. */
+ anfds [fd].emask = EV_EMASK_EPERM;
+
+ /* add fd to epoll_eperms, if not already inside */
+ if (!(oldmask & EV_EMASK_EPERM))
+ {
+ array_needsize (int, epoll_eperms, epoll_epermmax, epoll_epermcnt + 1, array_needsize_noinit);
+ epoll_eperms [epoll_epermcnt++] = fd;
+ }
+
+ return;
+ }
+ else
+ assert (("libev: I/O watcher with invalid fd found in epoll_ctl", errno != EBADF && errno != ELOOP && errno != EINVAL));
+
+ fd_kill (EV_A_ fd);
+
+dec_egen:
+ /* we didn't successfully call epoll_ctl, so decrement the generation counter again */
+ --anfds [fd].egen;
+}
+
+static void
+epoll_poll (EV_P_ ev_tstamp timeout)
+{
+ int i;
+ int eventcnt;
+
+ if (ecb_expect_false (epoll_epermcnt))
+ timeout = EV_TS_CONST (0.);
+
+ /* epoll wait times cannot be larger than (LONG_MAX - 999UL) / HZ msecs, which is below */
+ /* the default libev max wait time, however. */
+ EV_RELEASE_CB;
+ eventcnt = epoll_wait (backend_fd, epoll_events, epoll_eventmax, EV_TS_TO_MSEC (timeout));
+ EV_ACQUIRE_CB;
+
+ if (ecb_expect_false (eventcnt < 0))
+ {
+ if (errno != EINTR)
+ ev_syserr ("(libev) epoll_wait");
+
+ return;
+ }
+
+ for (i = 0; i < eventcnt; ++i)
+ {
+ struct epoll_event *ev = epoll_events + i;
+
+ int fd = (uint32_t)ev->data.u64; /* mask out the lower 32 bits */
+ int want = anfds [fd].events;
+ int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0)
+ | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0);
+
+ /*
+ * check for spurious notification.
+ * this only finds spurious notifications on egen updates
+ * other spurious notifications will be found by epoll_ctl, below
+ * we assume that fd is always in range, as we never shrink the anfds array
+ */
+ if (ecb_expect_false ((uint32_t)anfds [fd].egen != (uint32_t)(ev->data.u64 >> 32)))
+ {
+ /* recreate kernel state */
+ postfork |= 2;
+ continue;
+ }
+
+ if (ecb_expect_false (got & ~want))
+ {
+ anfds [fd].emask = want;
+
+ /*
+ * we received an event but are not interested in it, try mod or del
+ * this often happens because we optimistically do not unregister fds
+ * when we are no longer interested in them, but also when we get spurious
+ * notifications for fds from another process. this is partially handled
+ * above with the gencounter check (== our fd is not the event fd), and
+ * partially here, when epoll_ctl returns an error (== a child has the fd
+ * but we closed it).
+ * note: for events such as POLLHUP, where we can't know whether it refers
+ * to EV_READ or EV_WRITE, we might issue redundant EPOLL_CTL_MOD calls.
+ */
+ ev->events = (want & EV_READ ? EPOLLIN : 0)
+ | (want & EV_WRITE ? EPOLLOUT : 0);
+
+ /* pre-2.6.9 kernels require a non-null pointer with EPOLL_CTL_DEL, */
+ /* which is fortunately easy to do for us. */
+ if (epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev))
+ {
+ postfork |= 2; /* an error occurred, recreate kernel state */
+ continue;
+ }
+ }
+
+ fd_event (EV_A_ fd, got);
+ }
+
+ /* if the receive array was full, increase its size */
+ if (ecb_expect_false (eventcnt == epoll_eventmax))
+ {
+ ev_free (epoll_events);
+ epoll_eventmax = array_nextsize (sizeof (struct epoll_event), epoll_eventmax, epoll_eventmax + 1);
+ epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax);
+ }
+
+ /* now synthesize events for all fds where epoll fails, while select works... */
+ for (i = epoll_epermcnt; i--; )
+ {
+ int fd = epoll_eperms [i];
+ unsigned char events = anfds [fd].events & (EV_READ | EV_WRITE);
+
+ if (anfds [fd].emask & EV_EMASK_EPERM && events)
+ fd_event (EV_A_ fd, events);
+ else
+ {
+ epoll_eperms [i] = epoll_eperms [--epoll_epermcnt];
+ anfds [fd].emask = 0;
+ }
+ }
+}
+
+static int
+epoll_epoll_create (void)
+{
+ int fd;
+
+#if defined EPOLL_CLOEXEC && !defined __ANDROID__
+ fd = epoll_create1 (EPOLL_CLOEXEC);
+
+ if (fd < 0 && (errno == EINVAL || errno == ENOSYS))
+#endif
+ {
+ fd = epoll_create (256);
+
+ if (fd >= 0)
+ fcntl (fd, F_SETFD, FD_CLOEXEC);
+ }
+
+ return fd;
+}
+
+inline_size
+int
+epoll_init (EV_P_ int flags)
+{
+ if ((backend_fd = epoll_epoll_create ()) < 0)
+ return 0;
+
+ backend_mintime = EV_TS_CONST (1e-3); /* epoll does sometimes return early, this is just to avoid the worst */
+ backend_modify = epoll_modify;
+ backend_poll = epoll_poll;
+
+ epoll_eventmax = 64; /* initial number of events receivable per poll */
+ epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax);
+
+ return EVBACKEND_EPOLL;
+}
+
+inline_size
+void
+epoll_destroy (EV_P)
+{
+ ev_free (epoll_events);
+ array_free (epoll_eperm, EMPTY);
+}
+
+ecb_cold
+static void
+epoll_fork (EV_P)
+{
+ close (backend_fd);
+
+ while ((backend_fd = epoll_epoll_create ()) < 0)
+ ev_syserr ("(libev) epoll_create");
+
+ fd_rearm_all (EV_A);
+}
+
diff --git a/3rdparty/libev/ev_iouring.c b/3rdparty/libev/ev_iouring.c
new file mode 100644
index 0000000..bfd3de6
--- /dev/null
+++ b/3rdparty/libev/ev_iouring.c
@@ -0,0 +1,694 @@
+/*
+ * libev linux io_uring fd activity backend
+ *
+ * Copyright (c) 2019-2020 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+/*
+ * general notes about linux io_uring:
+ *
+ * a) it's the best interface I have seen so far. on linux.
+ * b) best is not necessarily very good.
+ * c) it's better than the aio mess, doesn't suffer from the fork problems
+ * of linux aio or epoll and so on and so on. and you could do event stuff
+ * without any syscalls. what's not to like?
+ * d) ok, it's vastly more complex, but that's ok, really.
+ * e) why two mmaps instead of one? one would be more space-efficient,
+ * and I can't see what benefit two would have (other than being
+ * somehow resizable/relocatable, but that's apparently not possible).
+ * f) hmm, it's practically undebuggable (gdb can't access the memory, and
+ * the bizarre way structure offsets are communicated makes it hard to
+ * just print the ring buffer heads, even *iff* the memory were visible
+ * in gdb. but then, that's also ok, really.
+ * g) well, you cannot specify a timeout when waiting for events. no,
+ * seriously, the interface doesn't support a timeout. never seen _that_
+ * before. sure, you can use a timerfd, but that's another syscall
+ * you could have avoided. overall, this bizarre omission smells
+ * like a µ-optimisation by the io_uring author for his personal
+ * applications, to the detriment of everybody else who just wants
+ * an event loop. but, umm, ok, if that's all, it could be worse.
+ * (from what I gather from the author Jens Axboe, it simply didn't
+ * occur to him, and he made good on it by adding an unlimited nuber
+ * of timeouts later :).
+ * h) initially there was a hardcoded limit of 4096 outstanding events.
+ * later versions not only bump this to 32k, but also can handle
+ * an unlimited amount of events, so this only affects the batch size.
+ * i) unlike linux aio, you *can* register more then the limit
+ * of fd events. while early verisons of io_uring signalled an overflow
+ * and you ended up getting wet. 5.5+ does not do this anymore.
+ * j) but, oh my! it had exactly the same bugs as the linux aio backend,
+ * where some undocumented poll combinations just fail. fortunately,
+ * after finally reaching the author, he was more than willing to fix
+ * this probably in 5.6+.
+ * k) overall, the *API* itself is, I dare to say, not a total trainwreck.
+ * once the bugs ae fixed (probably in 5.6+), it will be without
+ * competition.
+ */
+
+/* TODO: use internal TIMEOUT */
+/* TODO: take advantage of single mmap, NODROP etc. */
+/* TODO: resize cq/sq size independently */
+
+#include <sys/timerfd.h>
+#include <sys/mman.h>
+#include <poll.h>
+#include <stdint.h>
+
+#define IOURING_INIT_ENTRIES 32
+
+/*****************************************************************************/
+/* syscall wrapdadoop - this section has the raw api/abi definitions */
+
+#include <linux/fs.h>
+#include <linux/types.h>
+
+/* mostly directly taken from the kernel or documentation */
+
+struct io_uring_sqe
+{
+ __u8 opcode;
+ __u8 flags;
+ __u16 ioprio;
+ __s32 fd;
+ union {
+ __u64 off;
+ __u64 addr2;
+ };
+ __u64 addr;
+ __u32 len;
+ union {
+ __kernel_rwf_t rw_flags;
+ __u32 fsync_flags;
+ __u16 poll_events;
+ __u32 sync_range_flags;
+ __u32 msg_flags;
+ __u32 timeout_flags;
+ __u32 accept_flags;
+ __u32 cancel_flags;
+ __u32 open_flags;
+ __u32 statx_flags;
+ };
+ __u64 user_data;
+ union {
+ __u16 buf_index;
+ __u64 __pad2[3];
+ };
+};
+
+struct io_uring_cqe
+{
+ __u64 user_data;
+ __s32 res;
+ __u32 flags;
+};
+
+struct io_sqring_offsets
+{
+ __u32 head;
+ __u32 tail;
+ __u32 ring_mask;
+ __u32 ring_entries;
+ __u32 flags;
+ __u32 dropped;
+ __u32 array;
+ __u32 resv1;
+ __u64 resv2;
+};
+
+struct io_cqring_offsets
+{
+ __u32 head;
+ __u32 tail;
+ __u32 ring_mask;
+ __u32 ring_entries;
+ __u32 overflow;
+ __u32 cqes;
+ __u64 resv[2];
+};
+
+struct io_uring_params
+{
+ __u32 sq_entries;
+ __u32 cq_entries;
+ __u32 flags;
+ __u32 sq_thread_cpu;
+ __u32 sq_thread_idle;
+ __u32 features;
+ __u32 resv[4];
+ struct io_sqring_offsets sq_off;
+ struct io_cqring_offsets cq_off;
+};
+
+#define IORING_SETUP_CQSIZE 0x00000008
+
+#define IORING_OP_POLL_ADD 6
+#define IORING_OP_POLL_REMOVE 7
+#define IORING_OP_TIMEOUT 11
+#define IORING_OP_TIMEOUT_REMOVE 12
+
+/* relative or absolute, reference clock is CLOCK_MONOTONIC */
+struct iouring_kernel_timespec
+{
+ int64_t tv_sec;
+ long long tv_nsec;
+};
+
+#define IORING_TIMEOUT_ABS 0x00000001
+
+#define IORING_ENTER_GETEVENTS 0x01
+
+#define IORING_OFF_SQ_RING 0x00000000ULL
+#define IORING_OFF_CQ_RING 0x08000000ULL
+#define IORING_OFF_SQES 0x10000000ULL
+
+#define IORING_FEAT_SINGLE_MMAP 0x00000001
+#define IORING_FEAT_NODROP 0x00000002
+#define IORING_FEAT_SUBMIT_STABLE 0x00000004
+
+inline_size
+int
+evsys_io_uring_setup (unsigned entries, struct io_uring_params *params)
+{
+ return ev_syscall2 (SYS_io_uring_setup, entries, params);
+}
+
+inline_size
+int
+evsys_io_uring_enter (int fd, unsigned to_submit, unsigned min_complete, unsigned flags, const sigset_t *sig, size_t sigsz)
+{
+ return ev_syscall6 (SYS_io_uring_enter, fd, to_submit, min_complete, flags, sig, sigsz);
+}
+
+/*****************************************************************************/
+/* actual backed implementation */
+
+/* we hope that volatile will make the compiler access this variables only once */
+#define EV_SQ_VAR(name) *(volatile unsigned *)((char *)iouring_sq_ring + iouring_sq_ ## name)
+#define EV_CQ_VAR(name) *(volatile unsigned *)((char *)iouring_cq_ring + iouring_cq_ ## name)
+
+/* the index array */
+#define EV_SQ_ARRAY ((unsigned *)((char *)iouring_sq_ring + iouring_sq_array))
+
+/* the submit/completion queue entries */
+#define EV_SQES ((struct io_uring_sqe *) iouring_sqes)
+#define EV_CQES ((struct io_uring_cqe *)((char *)iouring_cq_ring + iouring_cq_cqes))
+
+inline_speed
+int
+iouring_enter (EV_P_ ev_tstamp timeout)
+{
+ int res;
+
+ EV_RELEASE_CB;
+
+ res = evsys_io_uring_enter (iouring_fd, iouring_to_submit, 1,
+ timeout > EV_TS_CONST (0.) ? IORING_ENTER_GETEVENTS : 0, 0, 0);
+
+ assert (("libev: io_uring_enter did not consume all sqes", (res < 0 || res == iouring_to_submit)));
+
+ iouring_to_submit = 0;
+
+ EV_ACQUIRE_CB;
+
+ return res;
+}
+
+/* TODO: can we move things around so we don't need this forward-reference? */
+static void
+iouring_poll (EV_P_ ev_tstamp timeout);
+
+static
+struct io_uring_sqe *
+iouring_sqe_get (EV_P)
+{
+ unsigned tail;
+
+ for (;;)
+ {
+ tail = EV_SQ_VAR (tail);
+
+ if (ecb_expect_true (tail + 1 - EV_SQ_VAR (head) <= EV_SQ_VAR (ring_entries)))
+ break; /* whats the problem, we have free sqes */
+
+ /* queue full, need to flush and possibly handle some events */
+
+#if EV_FEATURE_CODE
+ /* first we ask the kernel nicely, most often this frees up some sqes */
+ int res = iouring_enter (EV_A_ EV_TS_CONST (0.));
+
+ ECB_MEMORY_FENCE_ACQUIRE; /* better safe than sorry */
+
+ if (res >= 0)
+ continue; /* yes, it worked, try again */
+#endif
+
+ /* some problem, possibly EBUSY - do the full poll and let it handle any issues */
+
+ iouring_poll (EV_A_ EV_TS_CONST (0.));
+ /* iouring_poll should have done ECB_MEMORY_FENCE_ACQUIRE for us */
+ }
+
+ /*assert (("libev: io_uring queue full after flush", tail + 1 - EV_SQ_VAR (head) <= EV_SQ_VAR (ring_entries)));*/
+
+ return EV_SQES + (tail & EV_SQ_VAR (ring_mask));
+}
+
+inline_size
+struct io_uring_sqe *
+iouring_sqe_submit (EV_P_ struct io_uring_sqe *sqe)
+{
+ unsigned idx = sqe - EV_SQES;
+
+ EV_SQ_ARRAY [idx] = idx;
+ ECB_MEMORY_FENCE_RELEASE;
+ ++EV_SQ_VAR (tail);
+ /*ECB_MEMORY_FENCE_RELEASE; /* for the time being we assume this is not needed */
+ ++iouring_to_submit;
+}
+
+/*****************************************************************************/
+
+/* when the timerfd expires we simply note the fact,
+ * as the purpose of the timerfd is to wake us up, nothing else.
+ * the next iteration should re-set it.
+ */
+static void
+iouring_tfd_cb (EV_P_ struct ev_io *w, int revents)
+{
+ iouring_tfd_to = EV_TSTAMP_HUGE;
+}
+
+/* called for full and partial cleanup */
+ecb_cold
+static int
+iouring_internal_destroy (EV_P)
+{
+ close (iouring_tfd);
+ close (iouring_fd);
+
+ if (iouring_sq_ring != MAP_FAILED) munmap (iouring_sq_ring, iouring_sq_ring_size);
+ if (iouring_cq_ring != MAP_FAILED) munmap (iouring_cq_ring, iouring_cq_ring_size);
+ if (iouring_sqes != MAP_FAILED) munmap (iouring_sqes , iouring_sqes_size );
+
+ if (ev_is_active (&iouring_tfd_w))
+ {
+ ev_ref (EV_A);
+ ev_io_stop (EV_A_ &iouring_tfd_w);
+ }
+}
+
+ecb_cold
+static int
+iouring_internal_init (EV_P)
+{
+ struct io_uring_params params = { 0 };
+
+ iouring_to_submit = 0;
+
+ iouring_tfd = -1;
+ iouring_sq_ring = MAP_FAILED;
+ iouring_cq_ring = MAP_FAILED;
+ iouring_sqes = MAP_FAILED;
+
+ if (!have_monotonic) /* cannot really happen, but what if11 */
+ return -1;
+
+ for (;;)
+ {
+ iouring_fd = evsys_io_uring_setup (iouring_entries, &params);
+
+ if (iouring_fd >= 0)
+ break; /* yippie */
+
+ if (errno != EINVAL)
+ return -1; /* we failed */
+
+#if TODO
+ if ((~params.features) & (IORING_FEAT_NODROP | IORING_FEATURE_SINGLE_MMAP | IORING_FEAT_SUBMIT_STABLE))
+ return -1; /* we require the above features */
+#endif
+
+ /* EINVAL: lots of possible reasons, but maybe
+ * it is because we hit the unqueryable hardcoded size limit
+ */
+
+ /* we hit the limit already, give up */
+ if (iouring_max_entries)
+ return -1;
+
+ /* first time we hit EINVAL? assume we hit the limit, so go back and retry */
+ iouring_entries >>= 1;
+ iouring_max_entries = iouring_entries;
+ }
+
+ iouring_sq_ring_size = params.sq_off.array + params.sq_entries * sizeof (unsigned);
+ iouring_cq_ring_size = params.cq_off.cqes + params.cq_entries * sizeof (struct io_uring_cqe);
+ iouring_sqes_size = params.sq_entries * sizeof (struct io_uring_sqe);
+
+ iouring_sq_ring = mmap (0, iouring_sq_ring_size, PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_POPULATE, iouring_fd, IORING_OFF_SQ_RING);
+ iouring_cq_ring = mmap (0, iouring_cq_ring_size, PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_POPULATE, iouring_fd, IORING_OFF_CQ_RING);
+ iouring_sqes = mmap (0, iouring_sqes_size, PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_POPULATE, iouring_fd, IORING_OFF_SQES);
+
+ if (iouring_sq_ring == MAP_FAILED || iouring_cq_ring == MAP_FAILED || iouring_sqes == MAP_FAILED)
+ return -1;
+
+ iouring_sq_head = params.sq_off.head;
+ iouring_sq_tail = params.sq_off.tail;
+ iouring_sq_ring_mask = params.sq_off.ring_mask;
+ iouring_sq_ring_entries = params.sq_off.ring_entries;
+ iouring_sq_flags = params.sq_off.flags;
+ iouring_sq_dropped = params.sq_off.dropped;
+ iouring_sq_array = params.sq_off.array;
+
+ iouring_cq_head = params.cq_off.head;
+ iouring_cq_tail = params.cq_off.tail;
+ iouring_cq_ring_mask = params.cq_off.ring_mask;
+ iouring_cq_ring_entries = params.cq_off.ring_entries;
+ iouring_cq_overflow = params.cq_off.overflow;
+ iouring_cq_cqes = params.cq_off.cqes;
+
+ iouring_tfd = timerfd_create (CLOCK_MONOTONIC, TFD_CLOEXEC);
+
+ if (iouring_tfd < 0)
+ return iouring_tfd;
+
+ iouring_tfd_to = EV_TSTAMP_HUGE;
+
+ return 0;
+}
+
+ecb_cold
+static void
+iouring_fork (EV_P)
+{
+ iouring_internal_destroy (EV_A);
+
+ while (iouring_internal_init (EV_A) < 0)
+ ev_syserr ("(libev) io_uring_setup");
+
+ fd_rearm_all (EV_A);
+
+ ev_io_stop (EV_A_ &iouring_tfd_w);
+ ev_io_set (EV_A_ &iouring_tfd_w, iouring_tfd, EV_READ);
+ ev_io_start (EV_A_ &iouring_tfd_w);
+}
+
+/*****************************************************************************/
+
+static void
+iouring_modify (EV_P_ int fd, int oev, int nev)
+{
+ if (oev)
+ {
+ /* we assume the sqe's are all "properly" initialised */
+ struct io_uring_sqe *sqe = iouring_sqe_get (EV_A);
+ sqe->opcode = IORING_OP_POLL_REMOVE;
+ sqe->fd = fd;
+ /* Jens Axboe notified me that user_data is not what is documented, but is
+ * some kind of unique ID that has to match, otherwise the request cannot
+ * be removed. Since we don't *really* have that, we pass in the old
+ * generation counter - if that fails, too bad, it will hopefully be removed
+ * at close time and then be ignored. */
+ sqe->addr = (uint32_t)fd | ((__u64)(uint32_t)anfds [fd].egen << 32);
+ sqe->user_data = (uint64_t)-1;
+ iouring_sqe_submit (EV_A_ sqe);
+
+ /* increment generation counter to avoid handling old events */
+ ++anfds [fd].egen;
+ }
+
+ if (nev)
+ {
+ struct io_uring_sqe *sqe = iouring_sqe_get (EV_A);
+ sqe->opcode = IORING_OP_POLL_ADD;
+ sqe->fd = fd;
+ sqe->addr = 0;
+ sqe->user_data = (uint32_t)fd | ((__u64)(uint32_t)anfds [fd].egen << 32);
+ sqe->poll_events =
+ (nev & EV_READ ? POLLIN : 0)
+ | (nev & EV_WRITE ? POLLOUT : 0);
+ iouring_sqe_submit (EV_A_ sqe);
+ }
+}
+
+inline_size
+void
+iouring_tfd_update (EV_P_ ev_tstamp timeout)
+{
+ ev_tstamp tfd_to = mn_now + timeout;
+
+ /* we assume there will be many iterations per timer change, so
+ * we only re-set the timerfd when we have to because its expiry
+ * is too late.
+ */
+ if (ecb_expect_false (tfd_to < iouring_tfd_to))
+ {
+ struct itimerspec its;
+
+ iouring_tfd_to = tfd_to;
+ EV_TS_SET (its.it_interval, 0.);
+ EV_TS_SET (its.it_value, tfd_to);
+
+ if (timerfd_settime (iouring_tfd, TFD_TIMER_ABSTIME, &its, 0) < 0)
+ assert (("libev: iouring timerfd_settime failed", 0));
+ }
+}
+
+inline_size
+void
+iouring_process_cqe (EV_P_ struct io_uring_cqe *cqe)
+{
+ int fd = cqe->user_data & 0xffffffffU;
+ uint32_t gen = cqe->user_data >> 32;
+ int res = cqe->res;
+
+ /* user_data -1 is a remove that we are not atm. interested in */
+ if (cqe->user_data == (uint64_t)-1)
+ return;
+
+ assert (("libev: io_uring fd must be in-bounds", fd >= 0 && fd < anfdmax));
+
+ /* documentation lies, of course. the result value is NOT like
+ * normal syscalls, but like linux raw syscalls, i.e. negative
+ * error numbers. fortunate, as otherwise there would be no way
+ * to get error codes at all. still, why not document this?
+ */
+
+ /* ignore event if generation doesn't match */
+ /* other than skipping removal events, */
+ /* this should actually be very rare */
+ if (ecb_expect_false (gen != (uint32_t)anfds [fd].egen))
+ return;
+
+ if (ecb_expect_false (res < 0))
+ {
+ /*TODO: EINVAL handling (was something failed with this fd)*/
+
+ if (res == -EBADF)
+ {
+ assert (("libev: event loop rejected bad fd", res != -EBADF));
+ fd_kill (EV_A_ fd);
+ }
+ else
+ {
+ errno = -res;
+ ev_syserr ("(libev) IORING_OP_POLL_ADD");
+ }
+
+ return;
+ }
+
+ /* feed events, we do not expect or handle POLLNVAL */
+ fd_event (
+ EV_A_
+ fd,
+ (res & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0)
+ | (res & (POLLIN | POLLERR | POLLHUP) ? EV_READ : 0)
+ );
+
+ /* io_uring is oneshot, so we need to re-arm the fd next iteration */
+ /* this also means we usually have to do at least one syscall per iteration */
+ anfds [fd].events = 0;
+ fd_change (EV_A_ fd, EV_ANFD_REIFY);
+}
+
+/* called when the event queue overflows */
+ecb_cold
+static void
+iouring_overflow (EV_P)
+{
+ /* we have two options, resize the queue (by tearing down
+ * everything and recreating it, or living with it
+ * and polling.
+ * we implement this by resizing the queue, and, if that fails,
+ * we just recreate the state on every failure, which
+ * kind of is a very inefficient poll.
+ * one danger is, due to the bios toward lower fds,
+ * we will only really get events for those, so
+ * maybe we need a poll() fallback, after all.
+ */
+ /*EV_CQ_VAR (overflow) = 0;*/ /* need to do this if we keep the state and poll manually */
+
+ fd_rearm_all (EV_A);
+
+ /* we double the size until we hit the hard-to-probe maximum */
+ if (!iouring_max_entries)
+ {
+ iouring_entries <<= 1;
+ iouring_fork (EV_A);
+ }
+ else
+ {
+ /* we hit the kernel limit, we should fall back to something else.
+ * we can either poll() a few times and hope for the best,
+ * poll always, or switch to epoll.
+ * TODO: is this necessary with newer kernels?
+ */
+
+ iouring_internal_destroy (EV_A);
+
+ /* this should make it so that on return, we don't call any uring functions */
+ iouring_to_submit = 0;
+
+ for (;;)
+ {
+ backend = epoll_init (EV_A_ 0);
+
+ if (backend)
+ break;
+
+ ev_syserr ("(libev) iouring switch to epoll");
+ }
+ }
+}
+
+/* handle any events in the completion queue, return true if there were any */
+static int
+iouring_handle_cq (EV_P)
+{
+ unsigned head, tail, mask;
+
+ head = EV_CQ_VAR (head);
+ ECB_MEMORY_FENCE_ACQUIRE;
+ tail = EV_CQ_VAR (tail);
+
+ if (head == tail)
+ return 0;
+
+ /* it can only overflow if we have events, yes, yes? */
+ if (ecb_expect_false (EV_CQ_VAR (overflow)))
+ {
+ iouring_overflow (EV_A);
+ return 1;
+ }
+
+ mask = EV_CQ_VAR (ring_mask);
+
+ do
+ iouring_process_cqe (EV_A_ &EV_CQES [head++ & mask]);
+ while (head != tail);
+
+ EV_CQ_VAR (head) = head;
+ ECB_MEMORY_FENCE_RELEASE;
+
+ return 1;
+}
+
+static void
+iouring_poll (EV_P_ ev_tstamp timeout)
+{
+ /* if we have events, no need for extra syscalls, but we might have to queue events */
+ /* we also clar the timeout if there are outstanding fdchanges */
+ /* the latter should only happen if both the sq and cq are full, most likely */
+ /* because we have a lot of event sources that immediately complete */
+ /* TODO: fdchacngecnt is always 0 because fd_reify does not have two buffers yet */
+ if (iouring_handle_cq (EV_A) || fdchangecnt)
+ timeout = EV_TS_CONST (0.);
+ else
+ /* no events, so maybe wait for some */
+ iouring_tfd_update (EV_A_ timeout);
+
+ /* only enter the kernel if we have something to submit, or we need to wait */
+ if (timeout || iouring_to_submit)
+ {
+ int res = iouring_enter (EV_A_ timeout);
+
+ if (ecb_expect_false (res < 0))
+ if (errno == EINTR)
+ /* ignore */;
+ else if (errno == EBUSY)
+ /* cq full, cannot submit - should be rare because we flush the cq first, so simply ignore */;
+ else
+ ev_syserr ("(libev) iouring setup");
+ else
+ iouring_handle_cq (EV_A);
+ }
+}
+
+inline_size
+int
+iouring_init (EV_P_ int flags)
+{
+ iouring_entries = IOURING_INIT_ENTRIES;
+ iouring_max_entries = 0;
+
+ if (iouring_internal_init (EV_A) < 0)
+ {
+ iouring_internal_destroy (EV_A);
+ return 0;
+ }
+
+ ev_io_init (&iouring_tfd_w, iouring_tfd_cb, iouring_tfd, EV_READ);
+ ev_set_priority (&iouring_tfd_w, EV_MINPRI);
+ ev_io_start (EV_A_ &iouring_tfd_w);
+ ev_unref (EV_A); /* watcher should not keep loop alive */
+
+ backend_modify = iouring_modify;
+ backend_poll = iouring_poll;
+
+ return EVBACKEND_IOURING;
+}
+
+inline_size
+void
+iouring_destroy (EV_P)
+{
+ iouring_internal_destroy (EV_A);
+}
+
diff --git a/3rdparty/libev/ev_kqueue.c b/3rdparty/libev/ev_kqueue.c
new file mode 100644
index 0000000..69c5147
--- /dev/null
+++ b/3rdparty/libev/ev_kqueue.c
@@ -0,0 +1,224 @@
+/*
+ * libev kqueue backend
+ *
+ * Copyright (c) 2007,2008,2009,2010,2011,2012,2013,2016,2019 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/event.h>
+#include <string.h>
+#include <errno.h>
+
+inline_speed
+void
+kqueue_change (EV_P_ int fd, int filter, int flags, int fflags)
+{
+ ++kqueue_changecnt;
+ array_needsize (struct kevent, kqueue_changes, kqueue_changemax, kqueue_changecnt, array_needsize_noinit);
+
+ EV_SET (&kqueue_changes [kqueue_changecnt - 1], fd, filter, flags, fflags, 0, 0);
+}
+
+/* OS X at least needs this */
+#ifndef EV_ENABLE
+# define EV_ENABLE 0
+#endif
+#ifndef NOTE_EOF
+# define NOTE_EOF 0
+#endif
+
+static void
+kqueue_modify (EV_P_ int fd, int oev, int nev)
+{
+ if (oev != nev)
+ {
+ if (oev & EV_READ)
+ kqueue_change (EV_A_ fd, EVFILT_READ , EV_DELETE, 0);
+
+ if (oev & EV_WRITE)
+ kqueue_change (EV_A_ fd, EVFILT_WRITE, EV_DELETE, 0);
+ }
+
+ /* to detect close/reopen reliably, we have to re-add */
+ /* event requests even when oev == nev */
+
+ if (nev & EV_READ)
+ kqueue_change (EV_A_ fd, EVFILT_READ , EV_ADD | EV_ENABLE, NOTE_EOF);
+
+ if (nev & EV_WRITE)
+ kqueue_change (EV_A_ fd, EVFILT_WRITE, EV_ADD | EV_ENABLE, NOTE_EOF);
+}
+
+static void
+kqueue_poll (EV_P_ ev_tstamp timeout)
+{
+ int res, i;
+ struct timespec ts;
+
+ /* need to resize so there is enough space for errors */
+ if (kqueue_changecnt > kqueue_eventmax)
+ {
+ ev_free (kqueue_events);
+ kqueue_eventmax = array_nextsize (sizeof (struct kevent), kqueue_eventmax, kqueue_changecnt);
+ kqueue_events = (struct kevent *)ev_malloc (sizeof (struct kevent) * kqueue_eventmax);
+ }
+
+ EV_RELEASE_CB;
+ EV_TS_SET (ts, timeout);
+ res = kevent (backend_fd, kqueue_changes, kqueue_changecnt, kqueue_events, kqueue_eventmax, &ts);
+ EV_ACQUIRE_CB;
+ kqueue_changecnt = 0;
+
+ if (ecb_expect_false (res < 0))
+ {
+ if (errno != EINTR)
+ ev_syserr ("(libev) kqueue kevent");
+
+ return;
+ }
+
+ for (i = 0; i < res; ++i)
+ {
+ int fd = kqueue_events [i].ident;
+
+ if (ecb_expect_false (kqueue_events [i].flags & EV_ERROR))
+ {
+ int err = kqueue_events [i].data;
+
+ /* we are only interested in errors for fds that we are interested in :) */
+ if (anfds [fd].events)
+ {
+ if (err == ENOENT) /* resubmit changes on ENOENT */
+ kqueue_modify (EV_A_ fd, 0, anfds [fd].events);
+ else if (err == EBADF) /* on EBADF, we re-check the fd */
+ {
+ if (fd_valid (fd))
+ kqueue_modify (EV_A_ fd, 0, anfds [fd].events);
+ else
+ {
+ assert (("libev: kqueue found invalid fd", 0));
+ fd_kill (EV_A_ fd);
+ }
+ }
+ else /* on all other errors, we error out on the fd */
+ {
+ assert (("libev: kqueue found invalid fd", 0));
+ fd_kill (EV_A_ fd);
+ }
+ }
+ }
+ else
+ fd_event (
+ EV_A_
+ fd,
+ kqueue_events [i].filter == EVFILT_READ ? EV_READ
+ : kqueue_events [i].filter == EVFILT_WRITE ? EV_WRITE
+ : 0
+ );
+ }
+
+ if (ecb_expect_false (res == kqueue_eventmax))
+ {
+ ev_free (kqueue_events);
+ kqueue_eventmax = array_nextsize (sizeof (struct kevent), kqueue_eventmax, kqueue_eventmax + 1);
+ kqueue_events = (struct kevent *)ev_malloc (sizeof (struct kevent) * kqueue_eventmax);
+ }
+}
+
+inline_size
+int
+kqueue_init (EV_P_ int flags)
+{
+ /* initialize the kernel queue */
+ kqueue_fd_pid = getpid ();
+ if ((backend_fd = kqueue ()) < 0)
+ return 0;
+
+ fcntl (backend_fd, F_SETFD, FD_CLOEXEC); /* not sure if necessary, hopefully doesn't hurt */
+
+ backend_mintime = EV_TS_CONST (1e-9); /* apparently, they did the right thing in freebsd */
+ backend_modify = kqueue_modify;
+ backend_poll = kqueue_poll;
+
+ kqueue_eventmax = 64; /* initial number of events receivable per poll */
+ kqueue_events = (struct kevent *)ev_malloc (sizeof (struct kevent) * kqueue_eventmax);
+
+ kqueue_changes = 0;
+ kqueue_changemax = 0;
+ kqueue_changecnt = 0;
+
+ return EVBACKEND_KQUEUE;
+}
+
+inline_size
+void
+kqueue_destroy (EV_P)
+{
+ ev_free (kqueue_events);
+ ev_free (kqueue_changes);
+}
+
+inline_size
+void
+kqueue_fork (EV_P)
+{
+ /* some BSD kernels don't just destroy the kqueue itself,
+ * but also close the fd, which isn't documented, and
+ * impossible to support properly.
+ * we remember the pid of the kqueue call and only close
+ * the fd if the pid is still the same.
+ * this leaks fds on sane kernels, but BSD interfaces are
+ * notoriously buggy and rarely get fixed.
+ */
+ pid_t newpid = getpid ();
+
+ if (newpid == kqueue_fd_pid)
+ close (backend_fd);
+
+ kqueue_fd_pid = newpid;
+ while ((backend_fd = kqueue ()) < 0)
+ ev_syserr ("(libev) kqueue");
+
+ fcntl (backend_fd, F_SETFD, FD_CLOEXEC);
+
+ /* re-register interest in fds */
+ fd_rearm_all (EV_A);
+}
+
+/* sys/event.h defines EV_ERROR */
+#undef EV_ERROR
+
diff --git a/3rdparty/libev/ev_linuxaio.c b/3rdparty/libev/ev_linuxaio.c
new file mode 100644
index 0000000..4687a70
--- /dev/null
+++ b/3rdparty/libev/ev_linuxaio.c
@@ -0,0 +1,620 @@
+/*
+ * libev linux aio fd activity backend
+ *
+ * Copyright (c) 2019 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+/*
+ * general notes about linux aio:
+ *
+ * a) at first, the linux aio IOCB_CMD_POLL functionality introduced in
+ * 4.18 looks too good to be true: both watchers and events can be
+ * batched, and events can even be handled in userspace using
+ * a ring buffer shared with the kernel. watchers can be canceled
+ * regardless of whether the fd has been closed. no problems with fork.
+ * ok, the ring buffer is 200% undocumented (there isn't even a
+ * header file), but otherwise, it's pure bliss!
+ * b) ok, watchers are one-shot, so you have to re-arm active ones
+ * on every iteration. so much for syscall-less event handling,
+ * but at least these re-arms can be batched, no big deal, right?
+ * c) well, linux as usual: the documentation lies to you: io_submit
+ * sometimes returns EINVAL because the kernel doesn't feel like
+ * handling your poll mask - ttys can be polled for POLLOUT,
+ * POLLOUT|POLLIN, but polling for POLLIN fails. just great,
+ * so we have to fall back to something else (hello, epoll),
+ * but at least the fallback can be slow, because these are
+ * exceptional cases, right?
+ * d) hmm, you have to tell the kernel the maximum number of watchers
+ * you want to queue when initialising the aio context. but of
+ * course the real limit is magically calculated in the kernel, and
+ * is often higher then we asked for. so we just have to destroy
+ * the aio context and re-create it a bit larger if we hit the limit.
+ * (starts to remind you of epoll? well, it's a bit more deterministic
+ * and less gambling, but still ugly as hell).
+ * e) that's when you find out you can also hit an arbitrary system-wide
+ * limit. or the kernel simply doesn't want to handle your watchers.
+ * what the fuck do we do then? you guessed it, in the middle
+ * of event handling we have to switch to 100% epoll polling. and
+ * that better is as fast as normal epoll polling, so you practically
+ * have to use the normal epoll backend with all its quirks.
+ * f) end result of this train wreck: it inherits all the disadvantages
+ * from epoll, while adding a number on its own. why even bother to use
+ * it? because if conditions are right and your fds are supported and you
+ * don't hit a limit, this backend is actually faster, doesn't gamble with
+ * your fds, batches watchers and events and doesn't require costly state
+ * recreates. well, until it does.
+ * g) all of this makes this backend use almost twice as much code as epoll.
+ * which in turn uses twice as much code as poll. and that#s not counting
+ * the fact that this backend also depends on the epoll backend, making
+ * it three times as much code as poll, or kqueue.
+ * h) bleah. why can't linux just do kqueue. sure kqueue is ugly, but by now
+ * it's clear that whatever linux comes up with is far, far, far worse.
+ */
+
+#include <sys/time.h> /* actually linux/time.h, but we must assume they are compatible */
+#include <poll.h>
+#include <linux/aio_abi.h>
+
+/*****************************************************************************/
+/* syscall wrapdadoop - this section has the raw api/abi definitions */
+
+#include <sys/syscall.h> /* no glibc wrappers */
+
+/* aio_abi.h is not versioned in any way, so we cannot test for its existance */
+#define IOCB_CMD_POLL 5
+
+/* taken from linux/fs/aio.c. yup, that's a .c file.
+ * not only is this totally undocumented, not even the source code
+ * can tell you what the future semantics of compat_features and
+ * incompat_features are, or what header_length actually is for.
+ */
+#define AIO_RING_MAGIC 0xa10a10a1
+#define EV_AIO_RING_INCOMPAT_FEATURES 0
+struct aio_ring
+{
+ unsigned id; /* kernel internal index number */
+ unsigned nr; /* number of io_events */
+ unsigned head; /* Written to by userland or by kernel. */
+ unsigned tail;
+
+ unsigned magic;
+ unsigned compat_features;
+ unsigned incompat_features;
+ unsigned header_length; /* size of aio_ring */
+
+ struct io_event io_events[0];
+};
+
+inline_size
+int
+evsys_io_setup (unsigned nr_events, aio_context_t *ctx_idp)
+{
+ return ev_syscall2 (SYS_io_setup, nr_events, ctx_idp);
+}
+
+inline_size
+int
+evsys_io_destroy (aio_context_t ctx_id)
+{
+ return ev_syscall1 (SYS_io_destroy, ctx_id);
+}
+
+inline_size
+int
+evsys_io_submit (aio_context_t ctx_id, long nr, struct iocb *cbp[])
+{
+ return ev_syscall3 (SYS_io_submit, ctx_id, nr, cbp);
+}
+
+inline_size
+int
+evsys_io_cancel (aio_context_t ctx_id, struct iocb *cbp, struct io_event *result)
+{
+ return ev_syscall3 (SYS_io_cancel, ctx_id, cbp, result);
+}
+
+inline_size
+int
+evsys_io_getevents (aio_context_t ctx_id, long min_nr, long nr, struct io_event *events, struct timespec *timeout)
+{
+ return ev_syscall5 (SYS_io_getevents, ctx_id, min_nr, nr, events, timeout);
+}
+
+/*****************************************************************************/
+/* actual backed implementation */
+
+ecb_cold
+static int
+linuxaio_nr_events (EV_P)
+{
+ /* we start with 16 iocbs and incraese from there
+ * that's tiny, but the kernel has a rather low system-wide
+ * limit that can be reached quickly, so let's be parsimonious
+ * with this resource.
+ * Rest assured, the kernel generously rounds up small and big numbers
+ * in different ways (but doesn't seem to charge you for it).
+ * The 15 here is because the kernel usually has a power of two as aio-max-nr,
+ * and this helps to take advantage of that limit.
+ */
+
+ /* we try to fill 4kB pages exactly.
+ * the ring buffer header is 32 bytes, every io event is 32 bytes.
+ * the kernel takes the io requests number, doubles it, adds 2
+ * and adds the ring buffer.
+ * the way we use this is by starting low, and then roughly doubling the
+ * size each time we hit a limit.
+ */
+
+ int requests = 15 << linuxaio_iteration;
+ int one_page = (4096
+ / sizeof (struct io_event) ) / 2; /* how many fit into one page */
+ int first_page = ((4096 - sizeof (struct aio_ring))
+ / sizeof (struct io_event) - 2) / 2; /* how many fit into the first page */
+
+ /* if everything fits into one page, use count exactly */
+ if (requests > first_page)
+ /* otherwise, round down to full pages and add the first page */
+ requests = requests / one_page * one_page + first_page;
+
+ return requests;
+}
+
+/* we use out own wrapper structure in case we ever want to do something "clever" */
+typedef struct aniocb
+{
+ struct iocb io;
+ /*int inuse;*/
+} *ANIOCBP;
+
+inline_size
+void
+linuxaio_array_needsize_iocbp (ANIOCBP *base, int offset, int count)
+{
+ while (count--)
+ {
+ /* TODO: quite the overhead to allocate every iocb separately, maybe use our own allocator? */
+ ANIOCBP iocb = (ANIOCBP)ev_malloc (sizeof (*iocb));
+
+ /* full zero initialise is probably not required at the moment, but
+ * this is not well documented, so we better do it.
+ */
+ memset (iocb, 0, sizeof (*iocb));
+
+ iocb->io.aio_lio_opcode = IOCB_CMD_POLL;
+ iocb->io.aio_fildes = offset;
+
+ base [offset++] = iocb;
+ }
+}
+
+ecb_cold
+static void
+linuxaio_free_iocbp (EV_P)
+{
+ while (linuxaio_iocbpmax--)
+ ev_free (linuxaio_iocbps [linuxaio_iocbpmax]);
+
+ linuxaio_iocbpmax = 0; /* next resize will completely reallocate the array, at some overhead */
+}
+
+static void
+linuxaio_modify (EV_P_ int fd, int oev, int nev)
+{
+ array_needsize (ANIOCBP, linuxaio_iocbps, linuxaio_iocbpmax, fd + 1, linuxaio_array_needsize_iocbp);
+ ANIOCBP iocb = linuxaio_iocbps [fd];
+ ANFD *anfd = &anfds [fd];
+
+ if (ecb_expect_false (iocb->io.aio_reqprio < 0))
+ {
+ /* we handed this fd over to epoll, so undo this first */
+ /* we do it manually because the optimisations on epoll_modify won't do us any good */
+ epoll_ctl (backend_fd, EPOLL_CTL_DEL, fd, 0);
+ anfd->emask = 0;
+ iocb->io.aio_reqprio = 0;
+ }
+ else if (ecb_expect_false (iocb->io.aio_buf))
+ {
+ /* iocb active, so cancel it first before resubmit */
+ /* this assumes we only ever get one call per fd per loop iteration */
+ for (;;)
+ {
+ /* on all relevant kernels, io_cancel fails with EINPROGRESS on "success" */
+ if (ecb_expect_false (evsys_io_cancel (linuxaio_ctx, &iocb->io, (struct io_event *)0) == 0))
+ break;
+
+ if (ecb_expect_true (errno == EINPROGRESS))
+ break;
+
+ /* the EINPROGRESS test is for nicer error message. clumsy. */
+ if (errno != EINTR)
+ {
+ assert (("libev: linuxaio unexpected io_cancel failed", errno != EINTR && errno != EINPROGRESS));
+ break;
+ }
+ }
+
+ /* increment generation counter to avoid handling old events */
+ ++anfd->egen;
+ }
+
+ iocb->io.aio_buf = (nev & EV_READ ? POLLIN : 0)
+ | (nev & EV_WRITE ? POLLOUT : 0);
+
+ if (nev)
+ {
+ iocb->io.aio_data = (uint32_t)fd | ((__u64)(uint32_t)anfd->egen << 32);
+
+ /* queue iocb up for io_submit */
+ /* this assumes we only ever get one call per fd per loop iteration */
+ ++linuxaio_submitcnt;
+ array_needsize (struct iocb *, linuxaio_submits, linuxaio_submitmax, linuxaio_submitcnt, array_needsize_noinit);
+ linuxaio_submits [linuxaio_submitcnt - 1] = &iocb->io;
+ }
+}
+
+static void
+linuxaio_epoll_cb (EV_P_ struct ev_io *w, int revents)
+{
+ epoll_poll (EV_A_ 0);
+}
+
+inline_speed
+void
+linuxaio_fd_rearm (EV_P_ int fd)
+{
+ anfds [fd].events = 0;
+ linuxaio_iocbps [fd]->io.aio_buf = 0;
+ fd_change (EV_A_ fd, EV_ANFD_REIFY);
+}
+
+static void
+linuxaio_parse_events (EV_P_ struct io_event *ev, int nr)
+{
+ while (nr)
+ {
+ int fd = ev->data & 0xffffffff;
+ uint32_t gen = ev->data >> 32;
+ int res = ev->res;
+
+ assert (("libev: iocb fd must be in-bounds", fd >= 0 && fd < anfdmax));
+
+ /* only accept events if generation counter matches */
+ if (ecb_expect_true (gen == (uint32_t)anfds [fd].egen))
+ {
+ /* feed events, we do not expect or handle POLLNVAL */
+ fd_event (
+ EV_A_
+ fd,
+ (res & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0)
+ | (res & (POLLIN | POLLERR | POLLHUP) ? EV_READ : 0)
+ );
+
+ /* linux aio is oneshot: rearm fd. TODO: this does more work than strictly needed */
+ linuxaio_fd_rearm (EV_A_ fd);
+ }
+
+ --nr;
+ ++ev;
+ }
+}
+
+/* get any events from ring buffer, return true if any were handled */
+static int
+linuxaio_get_events_from_ring (EV_P)
+{
+ struct aio_ring *ring = (struct aio_ring *)linuxaio_ctx;
+ unsigned head, tail;
+
+ /* the kernel reads and writes both of these variables, */
+ /* as a C extension, we assume that volatile use here */
+ /* both makes reads atomic and once-only */
+ head = *(volatile unsigned *)&ring->head;
+ ECB_MEMORY_FENCE_ACQUIRE;
+ tail = *(volatile unsigned *)&ring->tail;
+
+ if (head == tail)
+ return 0;
+
+ /* parse all available events, but only once, to avoid starvation */
+ if (ecb_expect_true (tail > head)) /* normal case around */
+ linuxaio_parse_events (EV_A_ ring->io_events + head, tail - head);
+ else /* wrapped around */
+ {
+ linuxaio_parse_events (EV_A_ ring->io_events + head, ring->nr - head);
+ linuxaio_parse_events (EV_A_ ring->io_events, tail);
+ }
+
+ ECB_MEMORY_FENCE_RELEASE;
+ /* as an extension to C, we hope that the volatile will make this atomic and once-only */
+ *(volatile unsigned *)&ring->head = tail;
+
+ return 1;
+}
+
+inline_size
+int
+linuxaio_ringbuf_valid (EV_P)
+{
+ struct aio_ring *ring = (struct aio_ring *)linuxaio_ctx;
+
+ return ecb_expect_true (ring->magic == AIO_RING_MAGIC)
+ && ring->incompat_features == EV_AIO_RING_INCOMPAT_FEATURES
+ && ring->header_length == sizeof (struct aio_ring); /* TODO: or use it to find io_event[0]? */
+}
+
+/* read at least one event from kernel, or timeout */
+inline_size
+void
+linuxaio_get_events (EV_P_ ev_tstamp timeout)
+{
+ struct timespec ts;
+ struct io_event ioev[8]; /* 256 octet stack space */
+ int want = 1; /* how many events to request */
+ int ringbuf_valid = linuxaio_ringbuf_valid (EV_A);
+
+ if (ecb_expect_true (ringbuf_valid))
+ {
+ /* if the ring buffer has any events, we don't wait or call the kernel at all */
+ if (linuxaio_get_events_from_ring (EV_A))
+ return;
+
+ /* if the ring buffer is empty, and we don't have a timeout, then don't call the kernel */
+ if (!timeout)
+ return;
+ }
+ else
+ /* no ringbuffer, request slightly larger batch */
+ want = sizeof (ioev) / sizeof (ioev [0]);
+
+ /* no events, so wait for some
+ * for fairness reasons, we do this in a loop, to fetch all events
+ */
+ for (;;)
+ {
+ int res;
+
+ EV_RELEASE_CB;
+
+ EV_TS_SET (ts, timeout);
+ res = evsys_io_getevents (linuxaio_ctx, 1, want, ioev, &ts);
+
+ EV_ACQUIRE_CB;
+
+ if (res < 0)
+ if (errno == EINTR)
+ /* ignored, retry */;
+ else
+ ev_syserr ("(libev) linuxaio io_getevents");
+ else if (res)
+ {
+ /* at least one event available, handle them */
+ linuxaio_parse_events (EV_A_ ioev, res);
+
+ if (ecb_expect_true (ringbuf_valid))
+ {
+ /* if we have a ring buffer, handle any remaining events in it */
+ linuxaio_get_events_from_ring (EV_A);
+
+ /* at this point, we should have handled all outstanding events */
+ break;
+ }
+ else if (res < want)
+ /* otherwise, if there were fewere events than we wanted, we assume there are no more */
+ break;
+ }
+ else
+ break; /* no events from the kernel, we are done */
+
+ timeout = EV_TS_CONST (0.); /* only wait in the first iteration */
+ }
+}
+
+inline_size
+int
+linuxaio_io_setup (EV_P)
+{
+ linuxaio_ctx = 0;
+ return evsys_io_setup (linuxaio_nr_events (EV_A), &linuxaio_ctx);
+}
+
+static void
+linuxaio_poll (EV_P_ ev_tstamp timeout)
+{
+ int submitted;
+
+ /* first phase: submit new iocbs */
+
+ /* io_submit might return less than the requested number of iocbs */
+ /* this is, afaics, only because of errors, but we go by the book and use a loop, */
+ /* which allows us to pinpoint the erroneous iocb */
+ for (submitted = 0; submitted < linuxaio_submitcnt; )
+ {
+ int res = evsys_io_submit (linuxaio_ctx, linuxaio_submitcnt - submitted, linuxaio_submits + submitted);
+
+ if (ecb_expect_false (res < 0))
+ if (errno == EINVAL)
+ {
+ /* This happens for unsupported fds, officially, but in my testing,
+ * also randomly happens for supported fds. We fall back to good old
+ * poll() here, under the assumption that this is a very rare case.
+ * See https://lore.kernel.org/patchwork/patch/1047453/ to see
+ * discussion about such a case (ttys) where polling for POLLIN
+ * fails but POLLIN|POLLOUT works.
+ */
+ struct iocb *iocb = linuxaio_submits [submitted];
+ epoll_modify (EV_A_ iocb->aio_fildes, 0, anfds [iocb->aio_fildes].events);
+ iocb->aio_reqprio = -1; /* mark iocb as epoll */
+
+ res = 1; /* skip this iocb - another iocb, another chance */
+ }
+ else if (errno == EAGAIN)
+ {
+ /* This happens when the ring buffer is full, or some other shit we
+ * don't know and isn't documented. Most likely because we have too
+ * many requests and linux aio can't be assed to handle them.
+ * In this case, we try to allocate a larger ring buffer, freeing
+ * ours first. This might fail, in which case we have to fall back to 100%
+ * epoll.
+ * God, how I hate linux not getting its act together. Ever.
+ */
+ evsys_io_destroy (linuxaio_ctx);
+ linuxaio_submitcnt = 0;
+
+ /* rearm all fds with active iocbs */
+ {
+ int fd;
+ for (fd = 0; fd < linuxaio_iocbpmax; ++fd)
+ if (linuxaio_iocbps [fd]->io.aio_buf)
+ linuxaio_fd_rearm (EV_A_ fd);
+ }
+
+ ++linuxaio_iteration;
+ if (linuxaio_io_setup (EV_A) < 0)
+ {
+ /* TODO: rearm all and recreate epoll backend from scratch */
+ /* TODO: might be more prudent? */
+
+ /* to bad, we can't get a new aio context, go 100% epoll */
+ linuxaio_free_iocbp (EV_A);
+ ev_io_stop (EV_A_ &linuxaio_epoll_w);
+ ev_ref (EV_A);
+ linuxaio_ctx = 0;
+
+ backend = EVBACKEND_EPOLL;
+ backend_modify = epoll_modify;
+ backend_poll = epoll_poll;
+ }
+
+ timeout = EV_TS_CONST (0.);
+ /* it's easiest to handle this mess in another iteration */
+ return;
+ }
+ else if (errno == EBADF)
+ {
+ assert (("libev: event loop rejected bad fd", errno != EBADF));
+ fd_kill (EV_A_ linuxaio_submits [submitted]->aio_fildes);
+
+ res = 1; /* skip this iocb */
+ }
+ else if (errno == EINTR) /* not seen in reality, not documented */
+ res = 0; /* silently ignore and retry */
+ else
+ {
+ ev_syserr ("(libev) linuxaio io_submit");
+ res = 0;
+ }
+
+ submitted += res;
+ }
+
+ linuxaio_submitcnt = 0;
+
+ /* second phase: fetch and parse events */
+
+ linuxaio_get_events (EV_A_ timeout);
+}
+
+inline_size
+int
+linuxaio_init (EV_P_ int flags)
+{
+ /* would be great to have a nice test for IOCB_CMD_POLL instead */
+ /* also: test some semi-common fd types, such as files and ttys in recommended_backends */
+ /* 4.18 introduced IOCB_CMD_POLL, 4.19 made epoll work, and we need that */
+ if (ev_linux_version () < 0x041300)
+ return 0;
+
+ if (!epoll_init (EV_A_ 0))
+ return 0;
+
+ linuxaio_iteration = 0;
+
+ if (linuxaio_io_setup (EV_A) < 0)
+ {
+ epoll_destroy (EV_A);
+ return 0;
+ }
+
+ ev_io_init (&linuxaio_epoll_w, linuxaio_epoll_cb, backend_fd, EV_READ);
+ ev_set_priority (&linuxaio_epoll_w, EV_MAXPRI);
+ ev_io_start (EV_A_ &linuxaio_epoll_w);
+ ev_unref (EV_A); /* watcher should not keep loop alive */
+
+ backend_modify = linuxaio_modify;
+ backend_poll = linuxaio_poll;
+
+ linuxaio_iocbpmax = 0;
+ linuxaio_iocbps = 0;
+
+ linuxaio_submits = 0;
+ linuxaio_submitmax = 0;
+ linuxaio_submitcnt = 0;
+
+ return EVBACKEND_LINUXAIO;
+}
+
+inline_size
+void
+linuxaio_destroy (EV_P)
+{
+ epoll_destroy (EV_A);
+ linuxaio_free_iocbp (EV_A);
+ evsys_io_destroy (linuxaio_ctx); /* fails in child, aio context is destroyed */
+}
+
+ecb_cold
+static void
+linuxaio_fork (EV_P)
+{
+ linuxaio_submitcnt = 0; /* all pointers were invalidated */
+ linuxaio_free_iocbp (EV_A); /* this frees all iocbs, which is very heavy-handed */
+ evsys_io_destroy (linuxaio_ctx); /* fails in child, aio context is destroyed */
+
+ linuxaio_iteration = 0; /* we start over in the child */
+
+ while (linuxaio_io_setup (EV_A) < 0)
+ ev_syserr ("(libev) linuxaio io_setup");
+
+ /* forking epoll should also effectively unregister all fds from the backend */
+ epoll_fork (EV_A);
+ /* epoll_fork already did this. hopefully */
+ /*fd_rearm_all (EV_A);*/
+
+ ev_io_stop (EV_A_ &linuxaio_epoll_w);
+ ev_io_set (EV_A_ &linuxaio_epoll_w, backend_fd, EV_READ);
+ ev_io_start (EV_A_ &linuxaio_epoll_w);
+}
+
diff --git a/3rdparty/libev/ev_poll.c b/3rdparty/libev/ev_poll.c
new file mode 100644
index 0000000..e5508dd
--- /dev/null
+++ b/3rdparty/libev/ev_poll.c
@@ -0,0 +1,156 @@
+/*
+ * libev poll fd activity backend
+ *
+ * Copyright (c) 2007,2008,2009,2010,2011,2016,2019 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#include <poll.h>
+
+inline_size
+void
+array_needsize_pollidx (int *base, int offset, int count)
+{
+ /* using memset (.., -1, ...) is tempting, we we try
+ * to be ultraportable
+ */
+ base += offset;
+ while (count--)
+ *base++ = -1;
+}
+
+static void
+poll_modify (EV_P_ int fd, int oev, int nev)
+{
+ int idx;
+
+ if (oev == nev)
+ return;
+
+ array_needsize (int, pollidxs, pollidxmax, fd + 1, array_needsize_pollidx);
+
+ idx = pollidxs [fd];
+
+ if (idx < 0) /* need to allocate a new pollfd */
+ {
+ pollidxs [fd] = idx = pollcnt++;
+ array_needsize (struct pollfd, polls, pollmax, pollcnt, array_needsize_noinit);
+ polls [idx].fd = fd;
+ }
+
+ assert (polls [idx].fd == fd);
+
+ if (nev)
+ polls [idx].events =
+ (nev & EV_READ ? POLLIN : 0)
+ | (nev & EV_WRITE ? POLLOUT : 0);
+ else /* remove pollfd */
+ {
+ pollidxs [fd] = -1;
+
+ if (ecb_expect_true (idx < --pollcnt))
+ {
+ polls [idx] = polls [pollcnt];
+ pollidxs [polls [idx].fd] = idx;
+ }
+ }
+}
+
+static void
+poll_poll (EV_P_ ev_tstamp timeout)
+{
+ struct pollfd *p;
+ int res;
+
+ EV_RELEASE_CB;
+ res = poll (polls, pollcnt, EV_TS_TO_MSEC (timeout));
+ EV_ACQUIRE_CB;
+
+ if (ecb_expect_false (res < 0))
+ {
+ if (errno == EBADF)
+ fd_ebadf (EV_A);
+ else if (errno == ENOMEM && !syserr_cb)
+ fd_enomem (EV_A);
+ else if (errno != EINTR)
+ ev_syserr ("(libev) poll");
+ }
+ else
+ for (p = polls; res; ++p)
+ {
+ assert (("libev: poll returned illegal result, broken BSD kernel?", p < polls + pollcnt));
+
+ if (ecb_expect_false (p->revents)) /* this expect is debatable */
+ {
+ --res;
+
+ if (ecb_expect_false (p->revents & POLLNVAL))
+ {
+ assert (("libev: poll found invalid fd in poll set", 0));
+ fd_kill (EV_A_ p->fd);
+ }
+ else
+ fd_event (
+ EV_A_
+ p->fd,
+ (p->revents & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0)
+ | (p->revents & (POLLIN | POLLERR | POLLHUP) ? EV_READ : 0)
+ );
+ }
+ }
+}
+
+inline_size
+int
+poll_init (EV_P_ int flags)
+{
+ backend_mintime = EV_TS_CONST (1e-3);
+ backend_modify = poll_modify;
+ backend_poll = poll_poll;
+
+ pollidxs = 0; pollidxmax = 0;
+ polls = 0; pollmax = 0; pollcnt = 0;
+
+ return EVBACKEND_POLL;
+}
+
+inline_size
+void
+poll_destroy (EV_P)
+{
+ ev_free (pollidxs);
+ ev_free (polls);
+}
+
diff --git a/3rdparty/libev/ev_port.c b/3rdparty/libev/ev_port.c
new file mode 100644
index 0000000..f4cd9d9
--- /dev/null
+++ b/3rdparty/libev/ev_port.c
@@ -0,0 +1,192 @@
+/*
+ * libev solaris event port backend
+ *
+ * Copyright (c) 2007,2008,2009,2010,2011,2019 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+/* useful reading:
+ *
+ * http://bugs.opensolaris.org/view_bug.do?bug_id=6268715 (random results)
+ * http://bugs.opensolaris.org/view_bug.do?bug_id=6455223 (just totally broken)
+ * http://bugs.opensolaris.org/view_bug.do?bug_id=6873782 (manpage ETIME)
+ * http://bugs.opensolaris.org/view_bug.do?bug_id=6874410 (implementation ETIME)
+ * http://www.mail-archive.com/networking-discuss@opensolaris.org/msg11898.html ETIME vs. nget
+ * http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/lib/libc/port/gen/event_port.c (libc)
+ * http://cvs.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/fs/portfs/port.c#1325 (kernel)
+ */
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <poll.h>
+#include <port.h>
+#include <string.h>
+#include <errno.h>
+
+inline_speed
+void
+port_associate_and_check (EV_P_ int fd, int ev)
+{
+ if (0 >
+ port_associate (
+ backend_fd, PORT_SOURCE_FD, fd,
+ (ev & EV_READ ? POLLIN : 0)
+ | (ev & EV_WRITE ? POLLOUT : 0),
+ 0
+ )
+ )
+ {
+ if (errno == EBADFD)
+ {
+ assert (("libev: port_associate found invalid fd", errno != EBADFD));
+ fd_kill (EV_A_ fd);
+ }
+ else
+ ev_syserr ("(libev) port_associate");
+ }
+}
+
+static void
+port_modify (EV_P_ int fd, int oev, int nev)
+{
+ /* we need to reassociate no matter what, as closes are
+ * once more silently being discarded.
+ */
+ if (!nev)
+ {
+ if (oev)
+ port_dissociate (backend_fd, PORT_SOURCE_FD, fd);
+ }
+ else
+ port_associate_and_check (EV_A_ fd, nev);
+}
+
+static void
+port_poll (EV_P_ ev_tstamp timeout)
+{
+ int res, i;
+ struct timespec ts;
+ uint_t nget = 1;
+
+ /* we initialise this to something we will skip in the loop, as */
+ /* port_getn can return with nget unchanged, but no indication */
+ /* whether it was the original value or has been updated :/ */
+ port_events [0].portev_source = 0;
+
+ EV_RELEASE_CB;
+ EV_TS_SET (ts, timeout);
+ res = port_getn (backend_fd, port_events, port_eventmax, &nget, &ts);
+ EV_ACQUIRE_CB;
+
+ /* port_getn may or may not set nget on error */
+ /* so we rely on port_events [0].portev_source not being updated */
+ if (res == -1 && errno != ETIME && errno != EINTR)
+ ev_syserr ("(libev) port_getn (see http://bugs.opensolaris.org/view_bug.do?bug_id=6268715, try LIBEV_FLAGS=3 env variable)");
+
+ for (i = 0; i < nget; ++i)
+ {
+ if (port_events [i].portev_source == PORT_SOURCE_FD)
+ {
+ int fd = port_events [i].portev_object;
+
+ fd_event (
+ EV_A_
+ fd,
+ (port_events [i].portev_events & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0)
+ | (port_events [i].portev_events & (POLLIN | POLLERR | POLLHUP) ? EV_READ : 0)
+ );
+
+ fd_change (EV_A_ fd, EV__IOFDSET);
+ }
+ }
+
+ if (ecb_expect_false (nget == port_eventmax))
+ {
+ ev_free (port_events);
+ port_eventmax = array_nextsize (sizeof (port_event_t), port_eventmax, port_eventmax + 1);
+ port_events = (port_event_t *)ev_malloc (sizeof (port_event_t) * port_eventmax);
+ }
+}
+
+inline_size
+int
+port_init (EV_P_ int flags)
+{
+ /* Initialize the kernel queue */
+ if ((backend_fd = port_create ()) < 0)
+ return 0;
+
+ assert (("libev: PORT_SOURCE_FD must not be zero", PORT_SOURCE_FD));
+
+ fcntl (backend_fd, F_SETFD, FD_CLOEXEC); /* not sure if necessary, hopefully doesn't hurt */
+
+ /* if my reading of the opensolaris kernel sources are correct, then
+ * opensolaris does something very stupid: it checks if the time has already
+ * elapsed and doesn't round up if that is the case, otherwise it DOES round
+ * up. Since we can't know what the case is, we need to guess by using a
+ * "large enough" timeout. Normally, 1e-9 would be correct.
+ */
+ backend_mintime = EV_TS_CONST (1e-3); /* needed to compensate for port_getn returning early */
+ backend_modify = port_modify;
+ backend_poll = port_poll;
+
+ port_eventmax = 64; /* initial number of events receivable per poll */
+ port_events = (port_event_t *)ev_malloc (sizeof (port_event_t) * port_eventmax);
+
+ return EVBACKEND_PORT;
+}
+
+inline_size
+void
+port_destroy (EV_P)
+{
+ ev_free (port_events);
+}
+
+inline_size
+void
+port_fork (EV_P)
+{
+ close (backend_fd);
+
+ while ((backend_fd = port_create ()) < 0)
+ ev_syserr ("(libev) port");
+
+ fcntl (backend_fd, F_SETFD, FD_CLOEXEC);
+
+ /* re-register interest in fds */
+ fd_rearm_all (EV_A);
+}
+
diff --git a/3rdparty/libev/ev_select.c b/3rdparty/libev/ev_select.c
new file mode 100644
index 0000000..b862c81
--- /dev/null
+++ b/3rdparty/libev/ev_select.c
@@ -0,0 +1,316 @@
+/*
+ * libev select fd activity backend
+ *
+ * Copyright (c) 2007,2008,2009,2010,2011 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#ifndef _WIN32
+/* for unix systems */
+# include <inttypes.h>
+# ifndef __hpux
+/* for REAL unix systems */
+# include <sys/select.h>
+# endif
+#endif
+
+#ifndef EV_SELECT_USE_FD_SET
+# ifdef NFDBITS
+# define EV_SELECT_USE_FD_SET 0
+# else
+# define EV_SELECT_USE_FD_SET 1
+# endif
+#endif
+
+#if EV_SELECT_IS_WINSOCKET
+# undef EV_SELECT_USE_FD_SET
+# define EV_SELECT_USE_FD_SET 1
+# undef NFDBITS
+# define NFDBITS 0
+#endif
+
+#if !EV_SELECT_USE_FD_SET
+# define NFDBYTES (NFDBITS / 8)
+#endif
+
+#include <string.h>
+
+static void
+select_modify (EV_P_ int fd, int oev, int nev)
+{
+ if (oev == nev)
+ return;
+
+ {
+#if EV_SELECT_USE_FD_SET
+
+ #if EV_SELECT_IS_WINSOCKET
+ SOCKET handle = anfds [fd].handle;
+ #else
+ int handle = fd;
+ #endif
+
+ assert (("libev: fd >= FD_SETSIZE passed to fd_set-based select backend", fd < FD_SETSIZE));
+
+ /* FD_SET is broken on windows (it adds the fd to a set twice or more,
+ * which eventually leads to overflows). Need to call it only on changes.
+ */
+ #if EV_SELECT_IS_WINSOCKET
+ if ((oev ^ nev) & EV_READ)
+ #endif
+ if (nev & EV_READ)
+ FD_SET (handle, (fd_set *)vec_ri);
+ else
+ FD_CLR (handle, (fd_set *)vec_ri);
+
+ #if EV_SELECT_IS_WINSOCKET
+ if ((oev ^ nev) & EV_WRITE)
+ #endif
+ if (nev & EV_WRITE)
+ FD_SET (handle, (fd_set *)vec_wi);
+ else
+ FD_CLR (handle, (fd_set *)vec_wi);
+
+#else
+
+ int word = fd / NFDBITS;
+ fd_mask mask = 1UL << (fd % NFDBITS);
+
+ if (ecb_expect_false (vec_max <= word))
+ {
+ int new_max = word + 1;
+
+ vec_ri = ev_realloc (vec_ri, new_max * NFDBYTES);
+ vec_ro = ev_realloc (vec_ro, new_max * NFDBYTES); /* could free/malloc */
+ vec_wi = ev_realloc (vec_wi, new_max * NFDBYTES);
+ vec_wo = ev_realloc (vec_wo, new_max * NFDBYTES); /* could free/malloc */
+ #ifdef _WIN32
+ vec_eo = ev_realloc (vec_eo, new_max * NFDBYTES); /* could free/malloc */
+ #endif
+
+ for (; vec_max < new_max; ++vec_max)
+ ((fd_mask *)vec_ri) [vec_max] =
+ ((fd_mask *)vec_wi) [vec_max] = 0;
+ }
+
+ ((fd_mask *)vec_ri) [word] |= mask;
+ if (!(nev & EV_READ))
+ ((fd_mask *)vec_ri) [word] &= ~mask;
+
+ ((fd_mask *)vec_wi) [word] |= mask;
+ if (!(nev & EV_WRITE))
+ ((fd_mask *)vec_wi) [word] &= ~mask;
+#endif
+ }
+}
+
+static void
+select_poll (EV_P_ ev_tstamp timeout)
+{
+ struct timeval tv;
+ int res;
+ int fd_setsize;
+
+ EV_RELEASE_CB;
+ EV_TV_SET (tv, timeout);
+
+#if EV_SELECT_USE_FD_SET
+ fd_setsize = sizeof (fd_set);
+#else
+ fd_setsize = vec_max * NFDBYTES;
+#endif
+
+ memcpy (vec_ro, vec_ri, fd_setsize);
+ memcpy (vec_wo, vec_wi, fd_setsize);
+
+#ifdef _WIN32
+ /* pass in the write set as except set.
+ * the idea behind this is to work around a windows bug that causes
+ * errors to be reported as an exception and not by setting
+ * the writable bit. this is so uncontrollably lame.
+ */
+ memcpy (vec_eo, vec_wi, fd_setsize);
+ res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, (fd_set *)vec_eo, &tv);
+#elif EV_SELECT_USE_FD_SET
+ fd_setsize = anfdmax < FD_SETSIZE ? anfdmax : FD_SETSIZE;
+ res = select (fd_setsize, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
+#else
+ res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
+#endif
+ EV_ACQUIRE_CB;
+
+ if (ecb_expect_false (res < 0))
+ {
+ #if EV_SELECT_IS_WINSOCKET
+ errno = WSAGetLastError ();
+ #endif
+ #ifdef WSABASEERR
+ /* on windows, select returns incompatible error codes, fix this */
+ if (errno >= WSABASEERR && errno < WSABASEERR + 1000)
+ if (errno == WSAENOTSOCK)
+ errno = EBADF;
+ else
+ errno -= WSABASEERR;
+ #endif
+
+ #ifdef _WIN32
+ /* select on windows erroneously returns EINVAL when no fd sets have been
+ * provided (this is documented). what microsoft doesn't tell you that this bug
+ * exists even when the fd sets _are_ provided, so we have to check for this bug
+ * here and emulate by sleeping manually.
+ * we also get EINVAL when the timeout is invalid, but we ignore this case here
+ * and assume that EINVAL always means: you have to wait manually.
+ */
+ if (errno == EINVAL)
+ {
+ if (timeout)
+ {
+ unsigned long ms = EV_TS_TO_MSEC (timeout);
+ Sleep (ms ? ms : 1);
+ }
+
+ return;
+ }
+ #endif
+
+ if (errno == EBADF)
+ fd_ebadf (EV_A);
+ else if (errno == ENOMEM && !syserr_cb)
+ fd_enomem (EV_A);
+ else if (errno != EINTR)
+ ev_syserr ("(libev) select");
+
+ return;
+ }
+
+#if EV_SELECT_USE_FD_SET
+
+ {
+ int fd;
+
+ for (fd = 0; fd < anfdmax; ++fd)
+ if (anfds [fd].events)
+ {
+ int events = 0;
+ #if EV_SELECT_IS_WINSOCKET
+ SOCKET handle = anfds [fd].handle;
+ #else
+ int handle = fd;
+ #endif
+
+ if (FD_ISSET (handle, (fd_set *)vec_ro)) events |= EV_READ;
+ if (FD_ISSET (handle, (fd_set *)vec_wo)) events |= EV_WRITE;
+ #ifdef _WIN32
+ if (FD_ISSET (handle, (fd_set *)vec_eo)) events |= EV_WRITE;
+ #endif
+
+ if (ecb_expect_true (events))
+ fd_event (EV_A_ fd, events);
+ }
+ }
+
+#else
+
+ {
+ int word, bit;
+ for (word = vec_max; word--; )
+ {
+ fd_mask word_r = ((fd_mask *)vec_ro) [word];
+ fd_mask word_w = ((fd_mask *)vec_wo) [word];
+ #ifdef _WIN32
+ word_w |= ((fd_mask *)vec_eo) [word];
+ #endif
+
+ if (word_r || word_w)
+ for (bit = NFDBITS; bit--; )
+ {
+ fd_mask mask = 1UL << bit;
+ int events = 0;
+
+ events |= word_r & mask ? EV_READ : 0;
+ events |= word_w & mask ? EV_WRITE : 0;
+
+ if (ecb_expect_true (events))
+ fd_event (EV_A_ word * NFDBITS + bit, events);
+ }
+ }
+ }
+
+#endif
+}
+
+inline_size
+int
+select_init (EV_P_ int flags)
+{
+ backend_mintime = EV_TS_CONST (1e-6);
+ backend_modify = select_modify;
+ backend_poll = select_poll;
+
+#if EV_SELECT_USE_FD_SET
+ vec_ri = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_ri);
+ vec_ro = ev_malloc (sizeof (fd_set));
+ vec_wi = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_wi);
+ vec_wo = ev_malloc (sizeof (fd_set));
+ #ifdef _WIN32
+ vec_eo = ev_malloc (sizeof (fd_set));
+ #endif
+#else
+ vec_max = 0;
+ vec_ri = 0;
+ vec_ro = 0;
+ vec_wi = 0;
+ vec_wo = 0;
+ #ifdef _WIN32
+ vec_eo = 0;
+ #endif
+#endif
+
+ return EVBACKEND_SELECT;
+}
+
+inline_size
+void
+select_destroy (EV_P)
+{
+ ev_free (vec_ri);
+ ev_free (vec_ro);
+ ev_free (vec_wi);
+ ev_free (vec_wo);
+ #ifdef _WIN32
+ ev_free (vec_eo);
+ #endif
+}
+
diff --git a/3rdparty/libev/ev_vars.h b/3rdparty/libev/ev_vars.h
new file mode 100644
index 0000000..fb0c583
--- /dev/null
+++ b/3rdparty/libev/ev_vars.h
@@ -0,0 +1,249 @@
+/*
+ * loop member variable declarations
+ *
+ * Copyright (c) 2007,2008,2009,2010,2011,2012,2013,2019 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#define VARx(type,name) VAR(name, type name)
+
+VARx(ev_tstamp, now_floor) /* last time we refreshed rt_time */
+VARx(ev_tstamp, mn_now) /* monotonic clock "now" */
+VARx(ev_tstamp, rtmn_diff) /* difference realtime - monotonic time */
+
+/* for reverse feeding of events */
+VARx(W *, rfeeds)
+VARx(int, rfeedmax)
+VARx(int, rfeedcnt)
+
+VAR (pendings, ANPENDING *pendings [NUMPRI])
+VAR (pendingmax, int pendingmax [NUMPRI])
+VAR (pendingcnt, int pendingcnt [NUMPRI])
+VARx(int, pendingpri) /* highest priority currently pending */
+VARx(ev_prepare, pending_w) /* dummy pending watcher */
+
+VARx(ev_tstamp, io_blocktime)
+VARx(ev_tstamp, timeout_blocktime)
+
+VARx(int, backend)
+VARx(int, activecnt) /* total number of active events ("refcount") */
+VARx(EV_ATOMIC_T, loop_done) /* signal by ev_break */
+
+VARx(int, backend_fd)
+VARx(ev_tstamp, backend_mintime) /* assumed typical timer resolution */
+VAR (backend_modify, void (*backend_modify)(EV_P_ int fd, int oev, int nev))
+VAR (backend_poll , void (*backend_poll)(EV_P_ ev_tstamp timeout))
+
+VARx(ANFD *, anfds)
+VARx(int, anfdmax)
+
+VAR (evpipe, int evpipe [2])
+VARx(ev_io, pipe_w)
+VARx(EV_ATOMIC_T, pipe_write_wanted)
+VARx(EV_ATOMIC_T, pipe_write_skipped)
+
+#if !defined(_WIN32) || EV_GENWRAP
+VARx(pid_t, curpid)
+#endif
+
+VARx(char, postfork) /* true if we need to recreate kernel state after fork */
+
+#if EV_USE_SELECT || EV_GENWRAP
+VARx(void *, vec_ri)
+VARx(void *, vec_ro)
+VARx(void *, vec_wi)
+VARx(void *, vec_wo)
+#if defined(_WIN32) || EV_GENWRAP
+VARx(void *, vec_eo)
+#endif
+VARx(int, vec_max)
+#endif
+
+#if EV_USE_POLL || EV_GENWRAP
+VARx(struct pollfd *, polls)
+VARx(int, pollmax)
+VARx(int, pollcnt)
+VARx(int *, pollidxs) /* maps fds into structure indices */
+VARx(int, pollidxmax)
+#endif
+
+#if EV_USE_EPOLL || EV_GENWRAP
+VARx(struct epoll_event *, epoll_events)
+VARx(int, epoll_eventmax)
+VARx(int *, epoll_eperms)
+VARx(int, epoll_epermcnt)
+VARx(int, epoll_epermmax)
+#endif
+
+#if EV_USE_LINUXAIO || EV_GENWRAP
+VARx(aio_context_t, linuxaio_ctx)
+VARx(int, linuxaio_iteration)
+VARx(struct aniocb **, linuxaio_iocbps)
+VARx(int, linuxaio_iocbpmax)
+VARx(struct iocb **, linuxaio_submits)
+VARx(int, linuxaio_submitcnt)
+VARx(int, linuxaio_submitmax)
+VARx(ev_io, linuxaio_epoll_w)
+#endif
+
+#if EV_USE_IOURING || EV_GENWRAP
+VARx(int, iouring_fd)
+VARx(unsigned, iouring_to_submit);
+VARx(int, iouring_entries)
+VARx(int, iouring_max_entries)
+VARx(void *, iouring_sq_ring)
+VARx(void *, iouring_cq_ring)
+VARx(void *, iouring_sqes)
+VARx(uint32_t, iouring_sq_ring_size)
+VARx(uint32_t, iouring_cq_ring_size)
+VARx(uint32_t, iouring_sqes_size)
+VARx(uint32_t, iouring_sq_head)
+VARx(uint32_t, iouring_sq_tail)
+VARx(uint32_t, iouring_sq_ring_mask)
+VARx(uint32_t, iouring_sq_ring_entries)
+VARx(uint32_t, iouring_sq_flags)
+VARx(uint32_t, iouring_sq_dropped)
+VARx(uint32_t, iouring_sq_array)
+VARx(uint32_t, iouring_cq_head)
+VARx(uint32_t, iouring_cq_tail)
+VARx(uint32_t, iouring_cq_ring_mask)
+VARx(uint32_t, iouring_cq_ring_entries)
+VARx(uint32_t, iouring_cq_overflow)
+VARx(uint32_t, iouring_cq_cqes)
+VARx(ev_tstamp, iouring_tfd_to)
+VARx(int, iouring_tfd)
+VARx(ev_io, iouring_tfd_w)
+#endif
+
+#if EV_USE_KQUEUE || EV_GENWRAP
+VARx(pid_t, kqueue_fd_pid)
+VARx(struct kevent *, kqueue_changes)
+VARx(int, kqueue_changemax)
+VARx(int, kqueue_changecnt)
+VARx(struct kevent *, kqueue_events)
+VARx(int, kqueue_eventmax)
+#endif
+
+#if EV_USE_PORT || EV_GENWRAP
+VARx(struct port_event *, port_events)
+VARx(int, port_eventmax)
+#endif
+
+#if EV_USE_IOCP || EV_GENWRAP
+VARx(HANDLE, iocp)
+#endif
+
+VARx(int *, fdchanges)
+VARx(int, fdchangemax)
+VARx(int, fdchangecnt)
+
+VARx(ANHE *, timers)
+VARx(int, timermax)
+VARx(int, timercnt)
+
+#if EV_PERIODIC_ENABLE || EV_GENWRAP
+VARx(ANHE *, periodics)
+VARx(int, periodicmax)
+VARx(int, periodiccnt)
+#endif
+
+#if EV_IDLE_ENABLE || EV_GENWRAP
+VAR (idles, ev_idle **idles [NUMPRI])
+VAR (idlemax, int idlemax [NUMPRI])
+VAR (idlecnt, int idlecnt [NUMPRI])
+#endif
+VARx(int, idleall) /* total number */
+
+VARx(struct ev_prepare **, prepares)
+VARx(int, preparemax)
+VARx(int, preparecnt)
+
+VARx(struct ev_check **, checks)
+VARx(int, checkmax)
+VARx(int, checkcnt)
+
+#if EV_FORK_ENABLE || EV_GENWRAP
+VARx(struct ev_fork **, forks)
+VARx(int, forkmax)
+VARx(int, forkcnt)
+#endif
+
+#if EV_CLEANUP_ENABLE || EV_GENWRAP
+VARx(struct ev_cleanup **, cleanups)
+VARx(int, cleanupmax)
+VARx(int, cleanupcnt)
+#endif
+
+#if EV_ASYNC_ENABLE || EV_GENWRAP
+VARx(EV_ATOMIC_T, async_pending)
+VARx(struct ev_async **, asyncs)
+VARx(int, asyncmax)
+VARx(int, asynccnt)
+#endif
+
+#if EV_USE_INOTIFY || EV_GENWRAP
+VARx(int, fs_fd)
+VARx(ev_io, fs_w)
+VARx(char, fs_2625) /* whether we are running in linux 2.6.25 or newer */
+VAR (fs_hash, ANFS fs_hash [EV_INOTIFY_HASHSIZE])
+#endif
+
+VARx(EV_ATOMIC_T, sig_pending)
+#if EV_USE_SIGNALFD || EV_GENWRAP
+VARx(int, sigfd)
+VARx(ev_io, sigfd_w)
+VARx(sigset_t, sigfd_set)
+#endif
+
+#if EV_USE_TIMERFD || EV_GENWRAP
+VARx(int, timerfd) /* timerfd for time jump detection */
+VARx(ev_io, timerfd_w)
+#endif
+
+VARx(unsigned int, origflags) /* original loop flags */
+
+#if EV_FEATURE_API || EV_GENWRAP
+VARx(unsigned int, loop_count) /* total number of loop iterations/blocks */
+VARx(unsigned int, loop_depth) /* #ev_run enters - #ev_run leaves */
+
+VARx(void *, userdata)
+/* C++ doesn't support the ev_loop_callback typedef here. stinks. */
+VAR (release_cb, void (*release_cb)(EV_P) EV_NOEXCEPT)
+VAR (acquire_cb, void (*acquire_cb)(EV_P) EV_NOEXCEPT)
+VAR (invoke_cb , ev_loop_callback invoke_cb)
+#endif
+
+#undef VARx
+
diff --git a/3rdparty/libev/ev_win32.c b/3rdparty/libev/ev_win32.c
new file mode 100644
index 0000000..97344c3
--- /dev/null
+++ b/3rdparty/libev/ev_win32.c
@@ -0,0 +1,162 @@
+/*
+ * libev win32 compatibility cruft (_not_ a backend)
+ *
+ * Copyright (c) 2007,2008,2009 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#ifdef _WIN32
+
+/* note: the comment below could not be substantiated, but what would I care */
+/* MSDN says this is required to handle SIGFPE */
+/* my wild guess would be that using something floating-pointy is required */
+/* for the crt to do something about it */
+volatile double SIGFPE_REQ = 0.0f;
+
+static SOCKET
+ev_tcp_socket (void)
+{
+#if EV_USE_WSASOCKET
+ return WSASocket (AF_INET, SOCK_STREAM, 0, 0, 0, 0);
+#else
+ return socket (AF_INET, SOCK_STREAM, 0);
+#endif
+}
+
+/* oh, the humanity! */
+static int
+ev_pipe (int filedes [2])
+{
+ struct sockaddr_in addr = { 0 };
+ int addr_size = sizeof (addr);
+ struct sockaddr_in adr2;
+ int adr2_size = sizeof (adr2);
+ SOCKET listener;
+ SOCKET sock [2] = { -1, -1 };
+
+ if ((listener = ev_tcp_socket ()) == INVALID_SOCKET)
+ return -1;
+
+ addr.sin_family = AF_INET;
+ addr.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
+ addr.sin_port = 0;
+
+ if (bind (listener, (struct sockaddr *)&addr, addr_size))
+ goto fail;
+
+ if (getsockname (listener, (struct sockaddr *)&addr, &addr_size))
+ goto fail;
+
+ if (listen (listener, 1))
+ goto fail;
+
+ if ((sock [0] = ev_tcp_socket ()) == INVALID_SOCKET)
+ goto fail;
+
+ if (connect (sock [0], (struct sockaddr *)&addr, addr_size))
+ goto fail;
+
+ /* TODO: returns INVALID_SOCKET on winsock accept, not < 0. fix it */
+ /* when convenient, probably by just removing error checking altogether? */
+ if ((sock [1] = accept (listener, 0, 0)) < 0)
+ goto fail;
+
+ /* windows vista returns fantasy port numbers for sockets:
+ * example for two interconnected tcp sockets:
+ *
+ * (Socket::unpack_sockaddr_in getsockname $sock0)[0] == 53364
+ * (Socket::unpack_sockaddr_in getpeername $sock0)[0] == 53363
+ * (Socket::unpack_sockaddr_in getsockname $sock1)[0] == 53363
+ * (Socket::unpack_sockaddr_in getpeername $sock1)[0] == 53365
+ *
+ * wow! tridirectional sockets!
+ *
+ * this way of checking ports seems to work:
+ */
+ if (getpeername (sock [0], (struct sockaddr *)&addr, &addr_size))
+ goto fail;
+
+ if (getsockname (sock [1], (struct sockaddr *)&adr2, &adr2_size))
+ goto fail;
+
+ errno = WSAEINVAL;
+ if (addr_size != adr2_size
+ || addr.sin_addr.s_addr != adr2.sin_addr.s_addr /* just to be sure, I mean, it's windows */
+ || addr.sin_port != adr2.sin_port)
+ goto fail;
+
+ closesocket (listener);
+
+#if EV_SELECT_IS_WINSOCKET
+ filedes [0] = EV_WIN32_HANDLE_TO_FD (sock [0]);
+ filedes [1] = EV_WIN32_HANDLE_TO_FD (sock [1]);
+#else
+ /* when select isn't winsocket, we also expect socket, connect, accept etc.
+ * to work on fds */
+ filedes [0] = sock [0];
+ filedes [1] = sock [1];
+#endif
+
+ return 0;
+
+fail:
+ closesocket (listener);
+
+ if (sock [0] != INVALID_SOCKET) closesocket (sock [0]);
+ if (sock [1] != INVALID_SOCKET) closesocket (sock [1]);
+
+ return -1;
+}
+
+#undef pipe
+#define pipe(filedes) ev_pipe (filedes)
+
+#define EV_HAVE_EV_TIME 1
+ev_tstamp
+ev_time (void)
+{
+ FILETIME ft;
+ ULARGE_INTEGER ui;
+
+ GetSystemTimeAsFileTime (&ft);
+ ui.u.LowPart = ft.dwLowDateTime;
+ ui.u.HighPart = ft.dwHighDateTime;
+
+ /* also, msvc cannot convert ulonglong to double... yes, it is that sucky */
+ return EV_TS_FROM_USEC (((LONGLONG)(ui.QuadPart - 116444736000000000) * 1e-1));
+}
+
+#endif
+
diff --git a/3rdparty/libev/ev_wrap.h b/3rdparty/libev/ev_wrap.h
new file mode 100644
index 0000000..45d793c
--- /dev/null
+++ b/3rdparty/libev/ev_wrap.h
@@ -0,0 +1,272 @@
+/* DO NOT EDIT, automatically generated by update_ev_wrap */
+#ifndef EV_WRAP_H
+#define EV_WRAP_H
+#define acquire_cb ((loop)->acquire_cb)
+#define activecnt ((loop)->activecnt)
+#define anfdmax ((loop)->anfdmax)
+#define anfds ((loop)->anfds)
+#define async_pending ((loop)->async_pending)
+#define asynccnt ((loop)->asynccnt)
+#define asyncmax ((loop)->asyncmax)
+#define asyncs ((loop)->asyncs)
+#define backend ((loop)->backend)
+#define backend_fd ((loop)->backend_fd)
+#define backend_mintime ((loop)->backend_mintime)
+#define backend_modify ((loop)->backend_modify)
+#define backend_poll ((loop)->backend_poll)
+#define checkcnt ((loop)->checkcnt)
+#define checkmax ((loop)->checkmax)
+#define checks ((loop)->checks)
+#define cleanupcnt ((loop)->cleanupcnt)
+#define cleanupmax ((loop)->cleanupmax)
+#define cleanups ((loop)->cleanups)
+#define curpid ((loop)->curpid)
+#define epoll_epermcnt ((loop)->epoll_epermcnt)
+#define epoll_epermmax ((loop)->epoll_epermmax)
+#define epoll_eperms ((loop)->epoll_eperms)
+#define epoll_eventmax ((loop)->epoll_eventmax)
+#define epoll_events ((loop)->epoll_events)
+#define evpipe ((loop)->evpipe)
+#define fdchangecnt ((loop)->fdchangecnt)
+#define fdchangemax ((loop)->fdchangemax)
+#define fdchanges ((loop)->fdchanges)
+#define forkcnt ((loop)->forkcnt)
+#define forkmax ((loop)->forkmax)
+#define forks ((loop)->forks)
+#define fs_2625 ((loop)->fs_2625)
+#define fs_fd ((loop)->fs_fd)
+#define fs_hash ((loop)->fs_hash)
+#define fs_w ((loop)->fs_w)
+#define idleall ((loop)->idleall)
+#define idlecnt ((loop)->idlecnt)
+#define idlemax ((loop)->idlemax)
+#define idles ((loop)->idles)
+#define invoke_cb ((loop)->invoke_cb)
+#define io_blocktime ((loop)->io_blocktime)
+#define iocp ((loop)->iocp)
+#define iouring_cq_cqes ((loop)->iouring_cq_cqes)
+#define iouring_cq_head ((loop)->iouring_cq_head)
+#define iouring_cq_overflow ((loop)->iouring_cq_overflow)
+#define iouring_cq_ring ((loop)->iouring_cq_ring)
+#define iouring_cq_ring_entries ((loop)->iouring_cq_ring_entries)
+#define iouring_cq_ring_mask ((loop)->iouring_cq_ring_mask)
+#define iouring_cq_ring_size ((loop)->iouring_cq_ring_size)
+#define iouring_cq_tail ((loop)->iouring_cq_tail)
+#define iouring_entries ((loop)->iouring_entries)
+#define iouring_fd ((loop)->iouring_fd)
+#define iouring_max_entries ((loop)->iouring_max_entries)
+#define iouring_sq_array ((loop)->iouring_sq_array)
+#define iouring_sq_dropped ((loop)->iouring_sq_dropped)
+#define iouring_sq_flags ((loop)->iouring_sq_flags)
+#define iouring_sq_head ((loop)->iouring_sq_head)
+#define iouring_sq_ring ((loop)->iouring_sq_ring)
+#define iouring_sq_ring_entries ((loop)->iouring_sq_ring_entries)
+#define iouring_sq_ring_mask ((loop)->iouring_sq_ring_mask)
+#define iouring_sq_ring_size ((loop)->iouring_sq_ring_size)
+#define iouring_sq_tail ((loop)->iouring_sq_tail)
+#define iouring_sqes ((loop)->iouring_sqes)
+#define iouring_sqes_size ((loop)->iouring_sqes_size)
+#define iouring_tfd ((loop)->iouring_tfd)
+#define iouring_tfd_to ((loop)->iouring_tfd_to)
+#define iouring_tfd_w ((loop)->iouring_tfd_w)
+#define iouring_to_submit ((loop)->iouring_to_submit)
+#define kqueue_changecnt ((loop)->kqueue_changecnt)
+#define kqueue_changemax ((loop)->kqueue_changemax)
+#define kqueue_changes ((loop)->kqueue_changes)
+#define kqueue_eventmax ((loop)->kqueue_eventmax)
+#define kqueue_events ((loop)->kqueue_events)
+#define kqueue_fd_pid ((loop)->kqueue_fd_pid)
+#define linuxaio_ctx ((loop)->linuxaio_ctx)
+#define linuxaio_epoll_w ((loop)->linuxaio_epoll_w)
+#define linuxaio_iocbpmax ((loop)->linuxaio_iocbpmax)
+#define linuxaio_iocbps ((loop)->linuxaio_iocbps)
+#define linuxaio_iteration ((loop)->linuxaio_iteration)
+#define linuxaio_submitcnt ((loop)->linuxaio_submitcnt)
+#define linuxaio_submitmax ((loop)->linuxaio_submitmax)
+#define linuxaio_submits ((loop)->linuxaio_submits)
+#define loop_count ((loop)->loop_count)
+#define loop_depth ((loop)->loop_depth)
+#define loop_done ((loop)->loop_done)
+#define mn_now ((loop)->mn_now)
+#define now_floor ((loop)->now_floor)
+#define origflags ((loop)->origflags)
+#define pending_w ((loop)->pending_w)
+#define pendingcnt ((loop)->pendingcnt)
+#define pendingmax ((loop)->pendingmax)
+#define pendingpri ((loop)->pendingpri)
+#define pendings ((loop)->pendings)
+#define periodiccnt ((loop)->periodiccnt)
+#define periodicmax ((loop)->periodicmax)
+#define periodics ((loop)->periodics)
+#define pipe_w ((loop)->pipe_w)
+#define pipe_write_skipped ((loop)->pipe_write_skipped)
+#define pipe_write_wanted ((loop)->pipe_write_wanted)
+#define pollcnt ((loop)->pollcnt)
+#define pollidxmax ((loop)->pollidxmax)
+#define pollidxs ((loop)->pollidxs)
+#define pollmax ((loop)->pollmax)
+#define polls ((loop)->polls)
+#define port_eventmax ((loop)->port_eventmax)
+#define port_events ((loop)->port_events)
+#define postfork ((loop)->postfork)
+#define preparecnt ((loop)->preparecnt)
+#define preparemax ((loop)->preparemax)
+#define prepares ((loop)->prepares)
+#define release_cb ((loop)->release_cb)
+#define rfeedcnt ((loop)->rfeedcnt)
+#define rfeedmax ((loop)->rfeedmax)
+#define rfeeds ((loop)->rfeeds)
+#define rtmn_diff ((loop)->rtmn_diff)
+#define sig_pending ((loop)->sig_pending)
+#define sigfd ((loop)->sigfd)
+#define sigfd_set ((loop)->sigfd_set)
+#define sigfd_w ((loop)->sigfd_w)
+#define timeout_blocktime ((loop)->timeout_blocktime)
+#define timercnt ((loop)->timercnt)
+#define timerfd ((loop)->timerfd)
+#define timerfd_w ((loop)->timerfd_w)
+#define timermax ((loop)->timermax)
+#define timers ((loop)->timers)
+#define userdata ((loop)->userdata)
+#define vec_eo ((loop)->vec_eo)
+#define vec_max ((loop)->vec_max)
+#define vec_ri ((loop)->vec_ri)
+#define vec_ro ((loop)->vec_ro)
+#define vec_wi ((loop)->vec_wi)
+#define vec_wo ((loop)->vec_wo)
+#else
+#undef EV_WRAP_H
+#undef acquire_cb
+#undef activecnt
+#undef anfdmax
+#undef anfds
+#undef async_pending
+#undef asynccnt
+#undef asyncmax
+#undef asyncs
+#undef backend
+#undef backend_fd
+#undef backend_mintime
+#undef backend_modify
+#undef backend_poll
+#undef checkcnt
+#undef checkmax
+#undef checks
+#undef cleanupcnt
+#undef cleanupmax
+#undef cleanups
+#undef curpid
+#undef epoll_epermcnt
+#undef epoll_epermmax
+#undef epoll_eperms
+#undef epoll_eventmax
+#undef epoll_events
+#undef evpipe
+#undef fdchangecnt
+#undef fdchangemax
+#undef fdchanges
+#undef forkcnt
+#undef forkmax
+#undef forks
+#undef fs_2625
+#undef fs_fd
+#undef fs_hash
+#undef fs_w
+#undef idleall
+#undef idlecnt
+#undef idlemax
+#undef idles
+#undef invoke_cb
+#undef io_blocktime
+#undef iocp
+#undef iouring_cq_cqes
+#undef iouring_cq_head
+#undef iouring_cq_overflow
+#undef iouring_cq_ring
+#undef iouring_cq_ring_entries
+#undef iouring_cq_ring_mask
+#undef iouring_cq_ring_size
+#undef iouring_cq_tail
+#undef iouring_entries
+#undef iouring_fd
+#undef iouring_max_entries
+#undef iouring_sq_array
+#undef iouring_sq_dropped
+#undef iouring_sq_flags
+#undef iouring_sq_head
+#undef iouring_sq_ring
+#undef iouring_sq_ring_entries
+#undef iouring_sq_ring_mask
+#undef iouring_sq_ring_size
+#undef iouring_sq_tail
+#undef iouring_sqes
+#undef iouring_sqes_size
+#undef iouring_tfd
+#undef iouring_tfd_to
+#undef iouring_tfd_w
+#undef iouring_to_submit
+#undef kqueue_changecnt
+#undef kqueue_changemax
+#undef kqueue_changes
+#undef kqueue_eventmax
+#undef kqueue_events
+#undef kqueue_fd_pid
+#undef linuxaio_ctx
+#undef linuxaio_epoll_w
+#undef linuxaio_iocbpmax
+#undef linuxaio_iocbps
+#undef linuxaio_iteration
+#undef linuxaio_submitcnt
+#undef linuxaio_submitmax
+#undef linuxaio_submits
+#undef loop_count
+#undef loop_depth
+#undef loop_done
+#undef mn_now
+#undef now_floor
+#undef origflags
+#undef pending_w
+#undef pendingcnt
+#undef pendingmax
+#undef pendingpri
+#undef pendings
+#undef periodiccnt
+#undef periodicmax
+#undef periodics
+#undef pipe_w
+#undef pipe_write_skipped
+#undef pipe_write_wanted
+#undef pollcnt
+#undef pollidxmax
+#undef pollidxs
+#undef pollmax
+#undef polls
+#undef port_eventmax
+#undef port_events
+#undef postfork
+#undef preparecnt
+#undef preparemax
+#undef prepares
+#undef release_cb
+#undef rfeedcnt
+#undef rfeedmax
+#undef rfeeds
+#undef rtmn_diff
+#undef sig_pending
+#undef sigfd
+#undef sigfd_set
+#undef sigfd_w
+#undef timeout_blocktime
+#undef timercnt
+#undef timerfd
+#undef timerfd_w
+#undef timermax
+#undef timers
+#undef userdata
+#undef vec_eo
+#undef vec_max
+#undef vec_ri
+#undef vec_ro
+#undef vec_wi
+#undef vec_wo
+#endif
diff --git a/3rdparty/libev/event.c b/3rdparty/libev/event.c
new file mode 100644
index 0000000..5586cd3
--- /dev/null
+++ b/3rdparty/libev/event.c
@@ -0,0 +1,425 @@
+/*
+ * libevent compatibility layer
+ *
+ * Copyright (c) 2007,2008,2009,2010,2012 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#ifdef EV_EVENT_H
+# include EV_EVENT_H
+#else
+# include "event.h"
+#endif
+
+#if EV_MULTIPLICITY
+# define dLOOPev struct ev_loop *loop = (struct ev_loop *)ev->ev_base
+# define dLOOPbase struct ev_loop *loop = (struct ev_loop *)base
+#else
+# define dLOOPev
+# define dLOOPbase
+#endif
+
+/* never accessed, will always be cast from/to ev_loop */
+struct event_base
+{
+ int dummy;
+};
+
+static struct event_base *ev_x_cur;
+
+static ev_tstamp
+ev_tv_get (struct timeval *tv)
+{
+ if (tv)
+ {
+ ev_tstamp after = tv->tv_sec + tv->tv_usec * 1e-6;
+ return after ? after : 1e-6;
+ }
+ else
+ return -1.;
+}
+
+#define EVENT_STRINGIFY(s) # s
+#define EVENT_VERSION(a,b) EVENT_STRINGIFY (a) "." EVENT_STRINGIFY (b)
+
+const char *
+event_get_version (void)
+{
+ /* returns ABI, not API or library, version */
+ return EVENT_VERSION (EV_VERSION_MAJOR, EV_VERSION_MINOR);
+}
+
+const char *
+event_get_method (void)
+{
+ return "libev";
+}
+
+void *event_init (void)
+{
+#if EV_MULTIPLICITY
+ if (ev_x_cur)
+ ev_x_cur = (struct event_base *)ev_loop_new (EVFLAG_AUTO);
+ else
+ ev_x_cur = (struct event_base *)ev_default_loop (EVFLAG_AUTO);
+#else
+ assert (("libev: multiple event bases not supported when not compiled with EV_MULTIPLICITY", !ev_x_cur));
+
+ ev_x_cur = (struct event_base *)(long)ev_default_loop (EVFLAG_AUTO);
+#endif
+
+ return ev_x_cur;
+}
+
+const char *
+event_base_get_method (const struct event_base *base)
+{
+ return "libev";
+}
+
+struct event_base *
+event_base_new (void)
+{
+#if EV_MULTIPLICITY
+ return (struct event_base *)ev_loop_new (EVFLAG_AUTO);
+#else
+ assert (("libev: multiple event bases not supported when not compiled with EV_MULTIPLICITY"));
+ return NULL;
+#endif
+}
+
+void event_base_free (struct event_base *base)
+{
+ dLOOPbase;
+
+#if EV_MULTIPLICITY
+ if (!ev_is_default_loop (loop))
+ ev_loop_destroy (loop);
+#endif
+}
+
+int event_dispatch (void)
+{
+ return event_base_dispatch (ev_x_cur);
+}
+
+#ifdef EV_STANDALONE
+void event_set_log_callback (event_log_cb cb)
+{
+ /* nop */
+}
+#endif
+
+int event_loop (int flags)
+{
+ return event_base_loop (ev_x_cur, flags);
+}
+
+int event_loopexit (struct timeval *tv)
+{
+ return event_base_loopexit (ev_x_cur, tv);
+}
+
+event_callback_fn event_get_callback
+(const struct event *ev)
+{
+ return ev->ev_callback;
+}
+
+static void
+ev_x_cb (struct event *ev, int revents)
+{
+ revents &= EV_READ | EV_WRITE | EV_TIMER | EV_SIGNAL;
+
+ ev->ev_res = revents;
+ ev->ev_callback (ev->ev_fd, (short)revents, ev->ev_arg);
+}
+
+static void
+ev_x_cb_sig (EV_P_ struct ev_signal *w, int revents)
+{
+ struct event *ev = (struct event *)(((char *)w) - offsetof (struct event, iosig.sig));
+
+ if (revents & EV_ERROR)
+ event_del (ev);
+
+ ev_x_cb (ev, revents);
+}
+
+static void
+ev_x_cb_io (EV_P_ struct ev_io *w, int revents)
+{
+ struct event *ev = (struct event *)(((char *)w) - offsetof (struct event, iosig.io));
+
+ if ((revents & EV_ERROR) || !(ev->ev_events & EV_PERSIST))
+ event_del (ev);
+
+ ev_x_cb (ev, revents);
+}
+
+static void
+ev_x_cb_to (EV_P_ struct ev_timer *w, int revents)
+{
+ struct event *ev = (struct event *)(((char *)w) - offsetof (struct event, to));
+
+ event_del (ev);
+
+ ev_x_cb (ev, revents);
+}
+
+void event_set (struct event *ev, int fd, short events, void (*cb)(int, short, void *), void *arg)
+{
+ if (events & EV_SIGNAL)
+ ev_init (&ev->iosig.sig, ev_x_cb_sig);
+ else
+ ev_init (&ev->iosig.io, ev_x_cb_io);
+
+ ev_init (&ev->to, ev_x_cb_to);
+
+ ev->ev_base = ev_x_cur; /* not threadsafe, but it's how libevent works */
+ ev->ev_fd = fd;
+ ev->ev_events = events;
+ ev->ev_pri = 0;
+ ev->ev_callback = cb;
+ ev->ev_arg = arg;
+ ev->ev_res = 0;
+ ev->ev_flags = EVLIST_INIT;
+}
+
+int event_once (int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv)
+{
+ return event_base_once (ev_x_cur, fd, events, cb, arg, tv);
+}
+
+int event_add (struct event *ev, struct timeval *tv)
+{
+ dLOOPev;
+
+ if (ev->ev_events & EV_SIGNAL)
+ {
+ if (!ev_is_active (&ev->iosig.sig))
+ {
+ ev_signal_set (&ev->iosig.sig, ev->ev_fd);
+ ev_signal_start (EV_A_ &ev->iosig.sig);
+
+ ev->ev_flags |= EVLIST_SIGNAL;
+ }
+ }
+ else if (ev->ev_events & (EV_READ | EV_WRITE))
+ {
+ if (!ev_is_active (&ev->iosig.io))
+ {
+ ev_io_set (&ev->iosig.io, ev->ev_fd, ev->ev_events & (EV_READ | EV_WRITE));
+ ev_io_start (EV_A_ &ev->iosig.io);
+
+ ev->ev_flags |= EVLIST_INSERTED;
+ }
+ }
+
+ if (tv)
+ {
+ ev->to.repeat = ev_tv_get (tv);
+ ev_timer_again (EV_A_ &ev->to);
+ ev->ev_flags |= EVLIST_TIMEOUT;
+ }
+ else
+ {
+ ev_timer_stop (EV_A_ &ev->to);
+ ev->ev_flags &= ~EVLIST_TIMEOUT;
+ }
+
+ ev->ev_flags |= EVLIST_ACTIVE;
+
+ return 0;
+}
+
+int event_del (struct event *ev)
+{
+ dLOOPev;
+
+ if (ev->ev_events & EV_SIGNAL)
+ ev_signal_stop (EV_A_ &ev->iosig.sig);
+ else if (ev->ev_events & (EV_READ | EV_WRITE))
+ ev_io_stop (EV_A_ &ev->iosig.io);
+
+ if (ev_is_active (&ev->to))
+ ev_timer_stop (EV_A_ &ev->to);
+
+ ev->ev_flags = EVLIST_INIT;
+
+ return 0;
+}
+
+void event_active (struct event *ev, int res, short ncalls)
+{
+ dLOOPev;
+
+ if (res & EV_TIMEOUT)
+ ev_feed_event (EV_A_ &ev->to, res & EV_TIMEOUT);
+
+ if (res & EV_SIGNAL)
+ ev_feed_event (EV_A_ &ev->iosig.sig, res & EV_SIGNAL);
+
+ if (res & (EV_READ | EV_WRITE))
+ ev_feed_event (EV_A_ &ev->iosig.io, res & (EV_READ | EV_WRITE));
+}
+
+int event_pending (struct event *ev, short events, struct timeval *tv)
+{
+ short revents = 0;
+ dLOOPev;
+
+ if (ev->ev_events & EV_SIGNAL)
+ {
+ /* sig */
+ if (ev_is_active (&ev->iosig.sig) || ev_is_pending (&ev->iosig.sig))
+ revents |= EV_SIGNAL;
+ }
+ else if (ev->ev_events & (EV_READ | EV_WRITE))
+ {
+ /* io */
+ if (ev_is_active (&ev->iosig.io) || ev_is_pending (&ev->iosig.io))
+ revents |= ev->ev_events & (EV_READ | EV_WRITE);
+ }
+
+ if (ev->ev_events & EV_TIMEOUT || ev_is_active (&ev->to) || ev_is_pending (&ev->to))
+ {
+ revents |= EV_TIMEOUT;
+
+ if (tv)
+ {
+ ev_tstamp at = ev_now (EV_A);
+
+ tv->tv_sec = (long)at;
+ tv->tv_usec = (long)((at - (ev_tstamp)tv->tv_sec) * 1e6);
+ }
+ }
+
+ return events & revents;
+}
+
+int event_priority_init (int npri)
+{
+ return event_base_priority_init (ev_x_cur, npri);
+}
+
+int event_priority_set (struct event *ev, int pri)
+{
+ ev->ev_pri = pri;
+
+ return 0;
+}
+
+int event_base_set (struct event_base *base, struct event *ev)
+{
+ ev->ev_base = base;
+
+ return 0;
+}
+
+int event_base_loop (struct event_base *base, int flags)
+{
+ dLOOPbase;
+
+ return !ev_run (EV_A_ flags);
+}
+
+int event_base_dispatch (struct event_base *base)
+{
+ return event_base_loop (base, 0);
+}
+
+static void
+ev_x_loopexit_cb (int revents, void *base)
+{
+ dLOOPbase;
+
+ ev_break (EV_A_ EVBREAK_ONE);
+}
+
+int event_base_loopexit (struct event_base *base, struct timeval *tv)
+{
+ ev_tstamp after = ev_tv_get (tv);
+ dLOOPbase;
+
+ ev_once (EV_A_ -1, 0, after >= 0. ? after : 0., ev_x_loopexit_cb, (void *)base);
+
+ return 0;
+}
+
+struct ev_x_once
+{
+ int fd;
+ void (*cb)(int, short, void *);
+ void *arg;
+};
+
+static void
+ev_x_once_cb (int revents, void *arg)
+{
+ struct ev_x_once *once = (struct ev_x_once *)arg;
+
+ once->cb (once->fd, (short)revents, once->arg);
+ free (once);
+}
+
+int event_base_once (struct event_base *base, int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv)
+{
+ struct ev_x_once *once = (struct ev_x_once *)malloc (sizeof (struct ev_x_once));
+ dLOOPbase;
+
+ if (!once)
+ return -1;
+
+ once->fd = fd;
+ once->cb = cb;
+ once->arg = arg;
+
+ ev_once (EV_A_ fd, events & (EV_READ | EV_WRITE), ev_tv_get (tv), ev_x_once_cb, (void *)once);
+
+ return 0;
+}
+
+int event_base_priority_init (struct event_base *base, int npri)
+{
+ /*dLOOPbase;*/
+
+ return 0;
+}
+
diff --git a/3rdparty/libev/event.h b/3rdparty/libev/event.h
new file mode 100644
index 0000000..aa81928
--- /dev/null
+++ b/3rdparty/libev/event.h
@@ -0,0 +1,177 @@
+/*
+ * libevent compatibility header, only core events supported
+ *
+ * Copyright (c) 2007,2008,2010,2012 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#ifndef EVENT_H_
+#define EVENT_H_
+
+#ifdef EV_H
+# include EV_H
+#else
+# include "ev.h"
+#endif
+
+#ifndef EVLOOP_NONBLOCK
+# define EVLOOP_NONBLOCK EVRUN_NOWAIT
+#endif
+#ifndef EVLOOP_ONESHOT
+# define EVLOOP_ONESHOT EVRUN_ONCE
+#endif
+#ifndef EV_TIMEOUT
+# define EV_TIMEOUT EV_TIMER
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* we need sys/time.h for struct timeval only */
+#if !defined (WIN32) || defined (__MINGW32__)
+# include <time.h> /* mingw seems to need this, for whatever reason */
+# include <sys/time.h>
+#endif
+
+struct event_base;
+
+#define EVLIST_TIMEOUT 0x01
+#define EVLIST_INSERTED 0x02
+#define EVLIST_SIGNAL 0x04
+#define EVLIST_ACTIVE 0x08
+#define EVLIST_INTERNAL 0x10
+#define EVLIST_INIT 0x80
+
+typedef void (*event_callback_fn)(int, short, void *);
+
+struct event
+{
+ /* libev watchers we map onto */
+ union {
+ struct ev_io io;
+ struct ev_signal sig;
+ } iosig;
+ struct ev_timer to;
+
+ /* compatibility slots */
+ struct event_base *ev_base;
+ event_callback_fn ev_callback;
+ void *ev_arg;
+ int ev_fd;
+ int ev_pri;
+ int ev_res;
+ int ev_flags;
+ short ev_events;
+};
+
+event_callback_fn event_get_callback (const struct event *ev);
+
+#define EV_READ EV_READ
+#define EV_WRITE EV_WRITE
+#define EV_PERSIST 0x10
+#define EV_ET 0x20 /* nop */
+
+#define EVENT_SIGNAL(ev) ((int) (ev)->ev_fd)
+#define EVENT_FD(ev) ((int) (ev)->ev_fd)
+
+#define event_initialized(ev) ((ev)->ev_flags & EVLIST_INIT)
+
+#define evtimer_add(ev,tv) event_add (ev, tv)
+#define evtimer_set(ev,cb,data) event_set (ev, -1, 0, cb, data)
+#define evtimer_del(ev) event_del (ev)
+#define evtimer_pending(ev,tv) event_pending (ev, EV_TIMEOUT, tv)
+#define evtimer_initialized(ev) event_initialized (ev)
+
+#define timeout_add(ev,tv) evtimer_add (ev, tv)
+#define timeout_set(ev,cb,data) evtimer_set (ev, cb, data)
+#define timeout_del(ev) evtimer_del (ev)
+#define timeout_pending(ev,tv) evtimer_pending (ev, tv)
+#define timeout_initialized(ev) evtimer_initialized (ev)
+
+#define signal_add(ev,tv) event_add (ev, tv)
+#define signal_set(ev,sig,cb,data) event_set (ev, sig, EV_SIGNAL | EV_PERSIST, cb, data)
+#define signal_del(ev) event_del (ev)
+#define signal_pending(ev,tv) event_pending (ev, EV_SIGNAL, tv)
+#define signal_initialized(ev) event_initialized (ev)
+
+const char *event_get_version (void);
+const char *event_get_method (void);
+
+void *event_init (void);
+void event_base_free (struct event_base *base);
+
+#define EVLOOP_ONCE EVLOOP_ONESHOT
+int event_loop (int);
+int event_loopexit (struct timeval *tv);
+int event_dispatch (void);
+
+#define _EVENT_LOG_DEBUG 0
+#define _EVENT_LOG_MSG 1
+#define _EVENT_LOG_WARN 2
+#define _EVENT_LOG_ERR 3
+typedef void (*event_log_cb)(int severity, const char *msg);
+void event_set_log_callback(event_log_cb cb);
+
+void event_set (struct event *ev, int fd, short events, void (*cb)(int, short, void *), void *arg);
+int event_once (int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv);
+
+int event_add (struct event *ev, struct timeval *tv);
+int event_del (struct event *ev);
+void event_active (struct event *ev, int res, short ncalls); /* ncalls is being ignored */
+
+int event_pending (struct event *ev, short, struct timeval *tv);
+
+int event_priority_init (int npri);
+int event_priority_set (struct event *ev, int pri);
+
+struct event_base *event_base_new (void);
+const char *event_base_get_method (const struct event_base *);
+int event_base_set (struct event_base *base, struct event *ev);
+int event_base_loop (struct event_base *base, int);
+int event_base_loopexit (struct event_base *base, struct timeval *tv);
+int event_base_dispatch (struct event_base *base);
+int event_base_once (struct event_base *base, int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv);
+int event_base_priority_init (struct event_base *base, int fd);
+
+/* next line is different in the libevent+libev version */
+/*libevent-include*/
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
generated by cgit v1.2.3 (git 2.25.1) at 2026-01-03 00:29:43 +0000