/* * create.c * * Description: * This translation unit implements routines associated with spawning a new * thread. * * -------------------------------------------------------------------------- * * Pthreads4w - POSIX Threads Library for Win32 * Copyright(C) 1998 John E. Bossom * Copyright(C) 1999-2018, Pthreads4w contributors * * Homepage: https://sourceforge.net/projects/pthreads4w/ * * The current list of contributors is contained * in the file CONTRIBUTORS included with the source * code distribution. The list can also be seen at the * following World Wide Web location: * https://sourceforge.net/p/pthreads4w/wiki/Contributors/ * * This file is part of Pthreads4w. * * Pthreads4w is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * Pthreads4w is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with Pthreads4w. If not, see . * */ #ifdef HAVE_CONFIG_H # include #endif #include "pthread.h" #include "implement.h" #if ! defined(_UWIN) && ! defined(WINCE) #include #endif int pthread_create (pthread_t * tid, const pthread_attr_t * attr, void *(PTW32_CDECL *start) (void *), void *arg) /* * ------------------------------------------------------ * DOCPUBLIC * This function creates a thread running the start function, * passing it the parameter value, 'arg'. The 'attr' * argument specifies optional creation attributes. * The identity of the new thread is returned * via 'tid', which should not be NULL. * * PARAMETERS * tid * pointer to an instance of pthread_t * * attr * optional pointer to an instance of pthread_attr_t * * start * pointer to the starting routine for the new thread * * arg * optional parameter passed to 'start' * * * DESCRIPTION * This function creates a thread running the start function, * passing it the parameter value, 'arg'. The 'attr' * argument specifies optional creation attributes. * The identity of the new thread is returned * via 'tid', which should not be the NULL pointer. * * RESULTS * 0 successfully created thread, * EINVAL attr invalid, * EAGAIN insufficient resources. * * ------------------------------------------------------ */ { pthread_t thread; ptw32_thread_t * tp; ptw32_thread_t * sp; register pthread_attr_t a; HANDLE threadH = 0; int result = EAGAIN; int run = PTW32_TRUE; ThreadParms *parms = NULL; unsigned int stackSize; int priority; /* * Before doing anything, check that tid can be stored through * without invoking a memory protection error (segfault). * Make sure that the assignment below can't be optimised out by the compiler. * This is assured by conditionally assigning *tid again at the end. */ tid->x = 0; if (NULL == (sp = (ptw32_thread_t *)pthread_self().p)) { goto FAIL0; } if (attr != NULL) { a = *attr; } else { a = NULL; } thread = ptw32_new(); if (thread.p == NULL) { goto FAIL0; } tp = (ptw32_thread_t *) thread.p; priority = tp->sched_priority; if ((parms = (ThreadParms *) malloc (sizeof (*parms))) == NULL) { goto FAIL0; } parms->tid = thread; parms->start = start; parms->arg = arg; /* * Threads inherit their initial sigmask and CPU affinity from their creator thread. */ #if defined(HAVE_SIGSET_T) tp->sigmask = sp->sigmask; #endif #if defined(HAVE_CPU_AFFINITY) tp->cpuset = sp->cpuset; #endif if (a != NULL) { #if defined(HAVE_CPU_AFFINITY) cpu_set_t none; cpu_set_t attr_cpuset; ((_sched_cpu_set_vector_*)&attr_cpuset)->_cpuset = a->cpuset; CPU_ZERO(&none); if (! CPU_EQUAL(&attr_cpuset, &none)) { tp->cpuset = a->cpuset; } #endif stackSize = (unsigned int)a->stacksize; tp->detachState = a->detachstate; priority = a->param.sched_priority; if (a->thrname != NULL) tp->name = _strdup(a->thrname); #if (THREAD_PRIORITY_LOWEST > THREAD_PRIORITY_NORMAL) /* WinCE */ #else /* Everything else */ /* * Thread priority must be set to a valid system level * without altering the value set by pthread_attr_setschedparam(). */ /* * PTHREAD_EXPLICIT_SCHED is the default because Win32 threads * don't inherit their creator's priority. They are started with * THREAD_PRIORITY_NORMAL (win32 value). The result of not supplying * an 'attr' arg to pthread_create() is equivalent to defaulting to * PTHREAD_EXPLICIT_SCHED and priority THREAD_PRIORITY_NORMAL. */ if (PTHREAD_INHERIT_SCHED == a->inheritsched) { /* * If the thread that called pthread_create() is a Win32 thread * then the inherited priority could be the result of a temporary * system adjustment. This is not the case for POSIX threads. */ priority = sp->sched_priority; } #endif } else { /* * Default stackSize */ stackSize = PTHREAD_STACK_MIN; } tp->state = run ? PThreadStateInitial : PThreadStateSuspended; tp->keys = NULL; /* * Threads must be started in suspended mode and resumed if necessary * after _beginthreadex returns us the handle. Otherwise we set up a * race condition between the creating and the created threads. * Note that we also retain a local copy of the handle for use * by us in case thread.p->threadH gets NULLed later but before we've * finished with it here. */ #if ! defined (__MINGW32__) || defined (__MSVCRT__) || defined (__DMC__) tp->threadH = threadH = (HANDLE) _beginthreadex ((void *) NULL, /* No security info */ stackSize, /* default stack size */ ptw32_threadStart, parms, (unsigned) CREATE_SUSPENDED, (unsigned *) &(tp->thread)); if (threadH != 0) { if (a != NULL) { (void) ptw32_setthreadpriority (thread, SCHED_OTHER, priority); } #if defined(HAVE_CPU_AFFINITY) SetThreadAffinityMask(tp->threadH, tp->cpuset); #endif if (run) { ResumeThread (threadH); } } #else { ptw32_mcs_local_node_t stateLock; /* * This lock will force pthread_threadStart() to wait until we have * the thread handle and have set the priority. */ ptw32_mcs_lock_acquire(&tp->stateLock, &stateLock); tp->threadH = threadH = (HANDLE) _beginthread (ptw32_threadStart, stackSize, /* default stack size */ parms); /* * Make the return code match _beginthreadex's. */ if (threadH == (HANDLE) - 1L) { tp->threadH = threadH = 0; } else { if (!run) { /* * beginthread does not allow for create flags, so we do it now. * Note that beginthread itself creates the thread in SUSPENDED * mode, and then calls ResumeThread to start it. */ SuspendThread (threadH); } if (a != NULL) { (void) ptw32_setthreadpriority (thread, SCHED_OTHER, priority); } #if defined(HAVE_CPU_AFFINITY) SetThreadAffinityMask(tp->threadH, tp->cpuset); #endif } ptw32_mcs_lock_release (&stateLock); } #endif result = (threadH != 0) ? 0 : EAGAIN; /* * Fall Through Intentionally */ /* * ------------ * Failure Code * ------------ */ FAIL0: if (result != 0) { ptw32_threadDestroy (thread); tp = NULL; if (parms != NULL) { free (parms); } } else { *tid = thread; } #if defined(_UWIN) if (result == 0) pthread_count++; #endif return (result); } /* pthread_create */