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diff --git a/external-libs/pcre/doc/html/pcrebuild.html b/external-libs/pcre/doc/html/pcrebuild.html new file mode 100644 index 00000000..c70f8221 --- /dev/null +++ b/external-libs/pcre/doc/html/pcrebuild.html @@ -0,0 +1,189 @@ +<html> +<head> +<title>pcrebuild specification</title> +</head> +<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> +This HTML document has been generated automatically from the original man page. +If there is any nonsense in it, please consult the man page, in case the +conversion went wrong.<br> +<ul> +<li><a name="TOC1" href="#SEC1">PCRE BUILD-TIME OPTIONS</a> +<li><a name="TOC2" href="#SEC2">UTF-8 SUPPORT</a> +<li><a name="TOC3" href="#SEC3">CODE VALUE OF NEWLINE</a> +<li><a name="TOC4" href="#SEC4">BUILDING SHARED AND STATIC LIBRARIES</a> +<li><a name="TOC5" href="#SEC5">POSIX MALLOC USAGE</a> +<li><a name="TOC6" href="#SEC6">LIMITING PCRE RESOURCE USAGE</a> +<li><a name="TOC7" href="#SEC7">HANDLING VERY LARGE PATTERNS</a> +<li><a name="TOC8" href="#SEC8">AVOIDING EXCESSIVE STACK USAGE</a> +<li><a name="TOC9" href="#SEC9">USING EBCDIC CODE</a> +</ul> +<br><a name="SEC1" href="#TOC1">PCRE BUILD-TIME OPTIONS</a><br> +<P> +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 <b>configure</b> script which is run before the <b>make</b> +command. The complete list of options for <b>configure</b> (which includes the +standard ones such as the selection of the installation directory) can be +obtained by running +</P> +<P> +<pre> + ./configure --help +</PRE> +</P> +<P> +The following sections describe certain options whose names begin with --enable +or --disable. These settings specify changes to the defaults for the +<b>configure</b> command. Because of the way that <b>configure</b> 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. +</P> +<br><a name="SEC2" href="#TOC1">UTF-8 SUPPORT</a><br> +<P> +To build PCRE with support for UTF-8 character strings, add +</P> +<P> +<pre> + --enable-utf8 +</PRE> +</P> +<P> +to the <b>configure</b> 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 <b>pcre_compile()</b> +function. +</P> +<br><a name="SEC3" href="#TOC1">CODE VALUE OF NEWLINE</a><br> +<P> +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 +</P> +<P> +<pre> + --enable-newline-is-cr +</PRE> +</P> +<P> +to the <b>configure</b> command. For completeness there is also a +--enable-newline-is-lf option, which explicitly specifies linefeed as the +newline character. +</P> +<br><a name="SEC4" href="#TOC1">BUILDING SHARED AND STATIC LIBRARIES</a><br> +<P> +The PCRE building process uses <b>libtool</b> to build both shared and static +Unix libraries by default. You can suppress one of these by adding one of +</P> +<P> +<pre> + --disable-shared + --disable-static +</PRE> +</P> +<P> +to the <b>configure</b> command, as required. +</P> +<br><a name="SEC5" href="#TOC1">POSIX MALLOC USAGE</a><br> +<P> +When PCRE is called through the POSIX interface (see the <b>pcreposix</b> +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 <b>malloc()</b> 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 +</P> +<P> +<pre> + --with-posix-malloc-threshold=20 +</PRE> +</P> +<P> +to the <b>configure</b> command. +</P> +<br><a name="SEC6" href="#TOC1">LIMITING PCRE RESOURCE USAGE</a><br> +<P> +Internally, PCRE has a function called <b>match()</b> which it calls repeatedly +(possibly recursively) when performing a matching operation. By limiting the +number of times this function may be called, a limit can be placed on the +resources used by a single call to <b>pcre_exec()</b>. The limit can be changed +at run time, as described in the <b>pcreapi</b> documentation. The default is 10 +million, but this can be changed by adding a setting such as +</P> +<P> +<pre> + --with-match-limit=500000 +</PRE> +</P> +<P> +to the <b>configure</b> command. +</P> +<br><a name="SEC7" href="#TOC1">HANDLING VERY LARGE PATTERNS</a><br> +<P> +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 +</P> +<P> +<pre> + --with-link-size=3 +</PRE> +</P> +<P> +to the <b>configure</b> 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. +</P> +<P> +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. +</P> +<br><a name="SEC8" href="#TOC1">AVOIDING EXCESSIVE STACK USAGE</a><br> +<P> +PCRE implements backtracking while matching by making recursive calls to an +internal function called <b>match()</b>. 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 +</P> +<P> +<pre> + --disable-stack-for-recursion +</PRE> +</P> +<P> +to the <b>configure</b> command. With this configuration, PCRE will use the +<b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> 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 <b>malloc()</b> and +<b>free()</b> functions. PCRE runs noticeably more slowly when built in this +way. +</P> +<br><a name="SEC9" href="#TOC1">USING EBCDIC CODE</a><br> +<P> +PCRE assumes by default that it will run in an environment where the character +code is ASCII (or UTF-8, which is a superset of ASCII). PCRE can, however, be +compiled to run in an EBCDIC environment by adding +</P> +<P> +<pre> + --enable-ebcdic +</PRE> +</P> +<P> +to the <b>configure</b> command. +</P> +<P> +Last updated: 09 December 2003 +<br> +Copyright © 1997-2003 University of Cambridge. |