| <html> |
| <head> |
| <title>pcre specification</title> |
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| <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> |
| <h1>pcre man page</h1> |
| <p> |
| Return to the <a href="index.html">PCRE index page</a>. |
| </p> |
| <p> |
| This page is part of the PCRE HTML documentation. It was 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">INTRODUCTION</a> |
| <li><a name="TOC2" href="#SEC2">USER DOCUMENTATION</a> |
| <li><a name="TOC3" href="#SEC3">AUTHOR</a> |
| <li><a name="TOC4" href="#SEC4">REVISION</a> |
| </ul> |
| <br><a name="SEC1" href="#TOC1">INTRODUCTION</a><br> |
| <P> |
| The PCRE library is a set of functions that implement regular expression |
| pattern matching using the same syntax and semantics as Perl, with just a few |
| differences. Some features that appeared in Python and PCRE before they |
| appeared in Perl are also available using the Python syntax, there is some |
| support for one or two .NET and Oniguruma syntax items, and there is an option |
| for requesting some minor changes that give better JavaScript compatibility. |
| </P> |
| <P> |
| The current implementation of PCRE corresponds approximately with Perl 5.12, |
| including support for UTF-8 encoded strings and Unicode general category |
| properties. However, UTF-8 and Unicode support has to be explicitly enabled; it |
| is not the default. The Unicode tables correspond to Unicode release 6.0.0. |
| </P> |
| <P> |
| In addition to the Perl-compatible matching function, PCRE contains an |
| alternative function that matches the same compiled patterns in a different |
| way. In certain circumstances, the alternative function has some advantages. |
| For a discussion of the two matching algorithms, see the |
| <a href="pcrematching.html"><b>pcrematching</b></a> |
| page. |
| </P> |
| <P> |
| PCRE is written in C and released as a C library. A number of people have |
| written wrappers and interfaces of various kinds. In particular, Google Inc. |
| have provided a comprehensive C++ wrapper. This is now included as part of the |
| PCRE distribution. The |
| <a href="pcrecpp.html"><b>pcrecpp</b></a> |
| page has details of this interface. Other people's contributions can be found |
| in the <i>Contrib</i> directory at the primary FTP site, which is: |
| <a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre">ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre</a> |
| </P> |
| <P> |
| Details of exactly which Perl regular expression features are and are not |
| supported by PCRE are given in separate documents. See the |
| <a href="pcrepattern.html"><b>pcrepattern</b></a> |
| and |
| <a href="pcrecompat.html"><b>pcrecompat</b></a> |
| pages. There is a syntax summary in the |
| <a href="pcresyntax.html"><b>pcresyntax</b></a> |
| page. |
| </P> |
| <P> |
| Some features of PCRE can be included, excluded, or changed when the library is |
| built. The |
| <a href="pcre_config.html"><b>pcre_config()</b></a> |
| function makes it possible for a client to discover which features are |
| available. The features themselves are described in the |
| <a href="pcrebuild.html"><b>pcrebuild</b></a> |
| page. Documentation about building PCRE for various operating systems can be |
| found in the <b>README</b> and <b>NON-UNIX-USE</b> files in the source |
| distribution. |
| </P> |
| <P> |
| The library contains a number of undocumented internal functions and data |
| tables that are used by more than one of the exported external functions, but |
| which are not intended for use by external callers. Their names all begin with |
| "_pcre_", which hopefully will not provoke any name clashes. In some |
| environments, it is possible to control which external symbols are exported |
| when a shared library is built, and in these cases the undocumented symbols are |
| not exported. |
| </P> |
| <br><a name="SEC2" href="#TOC1">USER DOCUMENTATION</a><br> |
| <P> |
| The user documentation for PCRE comprises a number of different sections. In |
| the "man" format, each of these is a separate "man page". In the HTML format, |
| each is a separate page, linked from the index page. In the plain text format, |
| all the sections, except the <b>pcredemo</b> section, are concatenated, for ease |
| of searching. The sections are as follows: |
| <pre> |
| pcre this document |
| pcre-config show PCRE installation configuration information |
| pcreapi details of PCRE's native C API |
| pcrebuild options for building PCRE |
| pcrecallout details of the callout feature |
| pcrecompat discussion of Perl compatibility |
| pcrecpp details of the C++ wrapper |
| pcredemo a demonstration C program that uses PCRE |
| pcregrep description of the <b>pcregrep</b> command |
| pcrejit discussion of the just-in-time optimization support |
| pcrelimits details of size and other limits |
| pcrematching discussion of the two matching algorithms |
| pcrepartial details of the partial matching facility |
| pcrepattern syntax and semantics of supported regular expressions |
| pcreperform discussion of performance issues |
| pcreposix the POSIX-compatible C API |
| pcreprecompile details of saving and re-using precompiled patterns |
| pcresample discussion of the pcredemo program |
| pcrestack discussion of stack usage |
| pcresyntax quick syntax reference |
| pcretest description of the <b>pcretest</b> testing command |
| pcreunicode discussion of Unicode and UTF-8 support |
| </pre> |
| In addition, in the "man" and HTML formats, there is a short page for each |
| C library function, listing its arguments and results. |
| </P> |
| <br><a name="SEC3" href="#TOC1">AUTHOR</a><br> |
| <P> |
| Philip Hazel |
| <br> |
| University Computing Service |
| <br> |
| Cambridge CB2 3QH, England. |
| <br> |
| </P> |
| <P> |
| Putting an actual email address here seems to have been a spam magnet, so I've |
| taken it away. If you want to email me, use my two initials, followed by the |
| two digits 10, at the domain cam.ac.uk. |
| </P> |
| <br><a name="SEC4" href="#TOC1">REVISION</a><br> |
| <P> |
| Last updated: 24 August 2011 |
| <br> |
| Copyright © 1997-2011 University of Cambridge. |
| <br> |
| <p> |
| Return to the <a href="index.html">PCRE index page</a>. |
| </p> |