From 7fd9fe181150f166a098eaf4e006f878c28cb770 Mon Sep 17 00:00:00 2001 From: Gluzskiy Alexandr Date: Mon, 15 Feb 2010 05:51:01 +0300 Subject: sort --- Utilities/PCRE/man/html/pcrebuild.3.html | 167 +++++++++++++++++++++++++++++++ 1 file changed, 167 insertions(+) create mode 100644 Utilities/PCRE/man/html/pcrebuild.3.html (limited to 'Utilities/PCRE/man/html/pcrebuild.3.html') diff --git a/Utilities/PCRE/man/html/pcrebuild.3.html b/Utilities/PCRE/man/html/pcrebuild.3.html new file mode 100644 index 0000000..950a1f0 --- /dev/null +++ b/Utilities/PCRE/man/html/pcrebuild.3.html @@ -0,0 +1,167 @@ + + + + + +PCRE(3) manual page + + +Table of Contents

+ +

Name

+PCRE - Perl-compatible regular expressions +

Pcre Build-time Options

+

+This +document describes the optional features of PCRE that can be selected when +the library is compiled. They are all selected, or deselected, by providing +options to the configure script that is run before the make command. The +complete list of options for configure (which includes the standard ones +such as the selection of the installation directory) can be obtained by +running

+ ./configure --help
+

+The following sections describe certain options whose names begin with +--enable or --disable. These settings specify changes to the defaults for the +configure command. Because of the way that configure works, --enable and --disable +always come in pairs, so the complementary option always exists as well, +but as it specifies the default, it is not described. +

Utf-8 Support

+

+To build +PCRE with support for UTF-8 character strings, add

+ --enable-utf8
+

+to the configure command. Of itself, this does not make PCRE treat strings +as UTF-8. As well as compiling PCRE with this option, you also have have +to set the PCRE_UTF8 option when you call the pcre_compile() function. + +

Unicode Character Property Support

+

+UTF-8 support allows PCRE to process +character values greater than 255 in the strings that it handles. On its +own, however, it does not provide any facilities for accessing the properties +of such characters. If you want to be able to use the pattern escapes \P, +\p, and \X, which refer to Unicode character properties, you must add

+ --enable-unicode-properties
+

+to the configure command. This implies UTF-8 support, even if you have not +explicitly requested it.

+Including Unicode property support adds around +90K of tables to the PCRE library, approximately doubling its size. Only +the general category properties such as Lu and Nd are supported. Details +are given in the pcrepattern documentation. +

Code Value of Newline

+

+By +default, PCRE treats character 10 (linefeed) as the newline character. This +is the normal newline character on Unix-like systems. You can compile PCRE +to use character 13 (carriage return) instead by adding

+ --enable-newline-is-cr
+

+to the configure command. For completeness there is also a --enable-newline-is-lf +option, which explicitly specifies linefeed as the newline character. +

Building +Shared and Static Libraries

+

+The PCRE building process uses libtool to build +both shared and static Unix libraries by default. You can suppress one of +these by adding one of

+ --disable-shared
+ --disable-static
+

+to the configure command, as required. +

Posix Malloc Usage

+

+When PCRE is +called through the POSIX interface (see the pcreposix documentation), +additional working storage is required for holding the pointers to capturing +substrings, because PCRE requires three integers per substring, whereas +the POSIX interface provides only two. If the number of expected substrings +is small, the wrapper function uses space on the stack, because this is +faster than using malloc() for each call. The default threshold above which +the stack is no longer used is 10; it can be changed by adding a setting +such as

+ --with-posix-malloc-threshold=20
+

+to the configure command. +

Limiting Pcre Resource Usage

+

+Internally, PCRE +has a function called match(), which it calls repeatedly (possibly recursively) +when matching a pattern. By controlling the maximum number of times this +function may be called during a single matching operation, a limit can +be placed on the resources used by a single call to pcre_exec(). The limit +can be changed at run time, as described in the pcreapi documentation. +The default is 10 million, but this can be changed by adding a setting +such as

+ --with-match-limit=500000
+

+to the configure command. +

Handling Very Large Patterns

+

+Within a compiled +pattern, offset values are used to point from one part to another (for +example, from an opening parenthesis to an alternation metacharacter). By +default, two-byte values are used for these offsets, leading to a maximum +size for a compiled pattern of around 64K. This is sufficient to handle +all but the most gigantic patterns. Nevertheless, some people do want to +process enormous patterns, so it is possible to compile PCRE to use three-byte +or four-byte offsets by adding a setting such as

+ --with-link-size=3
+

+to the configure command. The value given must be 2, 3, or 4. Using longer +offsets slows down the operation of PCRE because it has to load additional +bytes when handling them.

+If you build PCRE with an increased link size, +test 2 (and test 5 if you are using UTF-8) will fail. Part of the output +of these tests is a representation of the compiled pattern, and this changes +with the link size. +

Avoiding Excessive Stack Usage

+

+PCRE implements backtracking +while matching by making recursive calls to an internal function called +match(). In environments where the size of the stack is limited, this can +severely limit PCRE’s operation. (The Unix environment does not usually suffer +from this problem.) An alternative approach that uses memory from the heap +to remember data, instead of using recursive function calls, has been implemented +to work round this problem. If you want to build a version of PCRE that +works this way, add

+ --disable-stack-for-recursion
+

+to the configure command. With this configuration, PCRE will use the pcre_stack_malloc +and pcre_stack_free variables to call memory management functions. Separate +functions are provided because the usage is very predictable: the block +sizes requested are always the same, and the blocks are always freed in +reverse order. A calling program might be able to implement optimized functions +that perform better than the standard malloc() and free() functions. PCRE +runs noticeably more slowly when built in this way. +

Using Ebcdic Code

+

+PCRE +assumes by default that it will run in an environment where the character +code is ASCII (or Unicode, which is a superset of ASCII). PCRE can, however, +be compiled to run in an EBCDIC environment by adding

+ --enable-ebcdic
+

+to the configure command.

+ Last updated: 09 September 2004
+Copyright (c) 1997-2004 University of Cambridge.

+ +

+Table of Contents

+

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