Documentation update.
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Philip.Hazel
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@ -42,18 +42,18 @@ the 16-bit library, which processes strings of 16-bit values, and one for the
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32-bit library, which processes strings of 32-bit values. There are no C++
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wrappers.
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The distribution does contain a set of C wrapper functions for the 8-bit
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library that are based on the POSIX regular expression API (see the pcre2posix
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man page). These can be found in a library called libpcre2-posix. Note that
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this just provides a POSIX calling interface to PCRE2; the regular expressions
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themselves still follow Perl syntax and semantics. The POSIX API is restricted,
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and does not give full access to all of PCRE2's facilities.
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In addition, the distribution contains a set of C wrapper functions for the
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8-bit library that are based on the POSIX regular expression API (see the
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pcre2posix man page). These are built into a library called libpcre2-posix.
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Note that this just provides a POSIX calling interface to PCRE2; the regular
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expressions themselves still follow Perl syntax and semantics. The POSIX API is
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restricted, and does not give full access to all of PCRE2's facilities.
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The header file for the POSIX-style functions is called pcre2posix.h. The
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official POSIX name is regex.h, but I did not want to risk possible problems
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with existing files of that name by distributing it that way. To use PCRE2 with
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an existing program that uses the POSIX API, pcre2posix.h will have to be
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renamed or pointed at by a link.
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renamed or pointed at by a link (or the program modified, of course).
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If you are using the POSIX interface to PCRE2 and there is already a POSIX
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regex library installed on your system, as well as worrying about the regex.h
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@ -61,12 +61,11 @@ header file (as mentioned above), you must also take care when linking programs
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to ensure that they link with PCRE2's libpcre2-posix library. Otherwise they
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may pick up the POSIX functions of the same name from the other library.
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One way of avoiding this confusion is to compile PCRE2 with the addition of
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-Dregcomp=PCRE2regcomp (and similarly for the other POSIX functions) to the
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compiler flags (CFLAGS if you are using "configure" -- see below). This has the
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effect of renaming the functions so that the names no longer clash. Of course,
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you have to do the same thing for your applications, or write them using the
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new names.
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To help with this issue, the libpcre2-posix library provides alternative names
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for the POSIX functions. These are the POSIX names, prefixed with "pcre2_", for
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example, pcre2_regcomp(). If an application can be compiled to use the
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alternative names (for example by the use of -Dregcomp=pcre2_regcomp etc.) it
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can be sure of linking with the PCRE2 functions.
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Documentation for PCRE2
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@ -888,4 +887,4 @@ The distribution should contain the files listed below.
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Philip Hazel
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Email local part: ph10
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Email domain: cam.ac.uk
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Last updated: 17 June 2018
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Last updated: 19 September 2018
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@ -32,15 +32,30 @@ please consult the man page, in case the conversion went wrong.
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<b> int <i>cflags</i>);</b>
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<br>
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<br>
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<b>int pcre2_regcomp(regex_t *<i>preg</i>, const char *<i>pattern</i>,</b>
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<b> int <i>cflags</i>);</b>
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<br>
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<br>
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<b>int regexec(const regex_t *<i>preg</i>, const char *<i>string</i>,</b>
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<b> size_t <i>nmatch</i>, regmatch_t <i>pmatch</i>[], int <i>eflags</i>);</b>
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<br>
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<br>
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<b>int pcre2_regexec(const regex_t *<i>preg</i>, const char *<i>string</i>,</b>
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<b> size_t <i>nmatch</i>, regmatch_t <i>pmatch</i>[], int <i>eflags</i>);</b>
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<br>
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<br>
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<b>size_t regerror(int <i>errcode</i>, const regex_t *<i>preg</i>,</b>
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<b> char *<i>errbuf</i>, size_t <i>errbuf_size</i>);</b>
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<br>
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<br>
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<b>size_t pcre2_regerror(int <i>errcode</i>, const regex_t *<i>preg</i>,</b>
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<b> char *<i>errbuf</i>, size_t <i>errbuf_size</i>);</b>
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<br>
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<br>
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<b>void regfree(regex_t *<i>preg</i>);</b>
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<br>
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<br>
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<b>void pcre2_regfree(regex_t *<i>preg</i>);</b>
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</P>
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<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
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<P>
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@ -60,6 +75,14 @@ command for linking an application that uses them. Because the POSIX functions
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call the native ones, it is also necessary to add <b>-lpcre2-8</b>.
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</P>
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<P>
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When another POSIX regex library is also installed, there is the possibility of
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linking an application with the wrong library. To help avoid this issue, the
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PCRE2 POSIX library provides alternative names for the functions, all starting
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with "pcre2_". If an application uses these names, possible ambiguity is
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avoided. In the following description, however, the standard POSIX function
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names are used.
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</P>
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<P>
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Those POSIX option bits that can reasonably be mapped to PCRE2 native options
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have been implemented. In addition, the option REG_EXTENDED is defined with the
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value zero. This has no effect, but since programs that are written to the
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@ -322,9 +345,9 @@ Cambridge, England.
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</P>
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<br><a name="SEC9" href="#TOC1">REVISION</a><br>
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<P>
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Last updated: 15 June 2017
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Last updated: 19 September 2018
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<br>
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Copyright © 1997-2017 University of Cambridge.
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Copyright © 1997-2018 University of Cambridge.
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<br>
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<p>
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Return to the <a href="index.html">PCRE2 index page</a>.
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@ -9419,14 +9419,25 @@ SYNOPSIS
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int regcomp(regex_t *preg, const char *pattern,
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int cflags);
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int pcre2_regcomp(regex_t *preg, const char *pattern,
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int cflags);
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int regexec(const regex_t *preg, const char *string,
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size_t nmatch, regmatch_t pmatch[], int eflags);
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int pcre2_regexec(const regex_t *preg, const char *string,
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size_t nmatch, regmatch_t pmatch[], int eflags);
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size_t regerror(int errcode, const regex_t *preg,
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char *errbuf, size_t errbuf_size);
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size_t pcre2_regerror(int errcode, const regex_t *preg,
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char *errbuf, size_t errbuf_size);
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void regfree(regex_t *preg);
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void pcre2_regfree(regex_t *preg);
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DESCRIPTION
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@ -9444,6 +9455,13 @@ DESCRIPTION
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POSIX functions call the native ones, it is also necessary to add
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-lpcre2-8.
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When another POSIX regex library is also installed, there is the possi-
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bility of linking an application with the wrong library. To help avoid
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this issue, the PCRE2 POSIX library provides alternative names for the
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functions, all starting with "pcre2_". If an application uses these
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names, possible ambiguity is avoided. In the following description,
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however, the standard POSIX function names are used.
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Those POSIX option bits that can reasonably be mapped to PCRE2 native
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options have been implemented. In addition, the option REG_EXTENDED is
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defined with the value zero. This has no effect, but since programs
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@ -9707,8 +9725,8 @@ AUTHOR
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REVISION
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Last updated: 15 June 2017
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Copyright (c) 1997-2017 University of Cambridge.
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Last updated: 19 September 2018
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Copyright (c) 1997-2018 University of Cambridge.
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------------------------------------------------------------------------------
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