| Tristan Matthews | 0461646 | 2013-11-14 16:09:34 -0500 | [diff] [blame] | 1 | <html> |
| 2 | <head> |
| 3 | <title>pcre specification</title> |
| 4 | </head> |
| 5 | <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> |
| 6 | <h1>pcre man page</h1> |
| 7 | <p> |
| 8 | Return to the <a href="index.html">PCRE index page</a>. |
| 9 | </p> |
| 10 | <p> |
| 11 | This page is part of the PCRE HTML documentation. It was generated automatically |
| 12 | from the original man page. If there is any nonsense in it, please consult the |
| 13 | man page, in case the conversion went wrong. |
| 14 | <br> |
| 15 | <ul> |
| 16 | <li><a name="TOC1" href="#SEC1">INTRODUCTION</a> |
| 17 | <li><a name="TOC2" href="#SEC2">USER DOCUMENTATION</a> |
| 18 | <li><a name="TOC3" href="#SEC3">AUTHOR</a> |
| 19 | <li><a name="TOC4" href="#SEC4">REVISION</a> |
| 20 | </ul> |
| 21 | <br><a name="SEC1" href="#TOC1">INTRODUCTION</a><br> |
| 22 | <P> |
| 23 | The PCRE library is a set of functions that implement regular expression |
| 24 | pattern matching using the same syntax and semantics as Perl, with just a few |
| 25 | differences. Some features that appeared in Python and PCRE before they |
| 26 | appeared in Perl are also available using the Python syntax, there is some |
| 27 | support for one or two .NET and Oniguruma syntax items, and there is an option |
| 28 | for requesting some minor changes that give better JavaScript compatibility. |
| 29 | </P> |
| 30 | <P> |
| 31 | The current implementation of PCRE corresponds approximately with Perl 5.12, |
| 32 | including support for UTF-8 encoded strings and Unicode general category |
| 33 | properties. However, UTF-8 and Unicode support has to be explicitly enabled; it |
| 34 | is not the default. The Unicode tables correspond to Unicode release 6.0.0. |
| 35 | </P> |
| 36 | <P> |
| 37 | In addition to the Perl-compatible matching function, PCRE contains an |
| 38 | alternative function that matches the same compiled patterns in a different |
| 39 | way. In certain circumstances, the alternative function has some advantages. |
| 40 | For a discussion of the two matching algorithms, see the |
| 41 | <a href="pcrematching.html"><b>pcrematching</b></a> |
| 42 | page. |
| 43 | </P> |
| 44 | <P> |
| 45 | PCRE is written in C and released as a C library. A number of people have |
| 46 | written wrappers and interfaces of various kinds. In particular, Google Inc. |
| 47 | have provided a comprehensive C++ wrapper. This is now included as part of the |
| 48 | PCRE distribution. The |
| 49 | <a href="pcrecpp.html"><b>pcrecpp</b></a> |
| 50 | page has details of this interface. Other people's contributions can be found |
| 51 | in the <i>Contrib</i> directory at the primary FTP site, which is: |
| 52 | <a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre">ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre</a> |
| 53 | </P> |
| 54 | <P> |
| 55 | Details of exactly which Perl regular expression features are and are not |
| 56 | supported by PCRE are given in separate documents. See the |
| 57 | <a href="pcrepattern.html"><b>pcrepattern</b></a> |
| 58 | and |
| 59 | <a href="pcrecompat.html"><b>pcrecompat</b></a> |
| 60 | pages. There is a syntax summary in the |
| 61 | <a href="pcresyntax.html"><b>pcresyntax</b></a> |
| 62 | page. |
| 63 | </P> |
| 64 | <P> |
| 65 | Some features of PCRE can be included, excluded, or changed when the library is |
| 66 | built. The |
| 67 | <a href="pcre_config.html"><b>pcre_config()</b></a> |
| 68 | function makes it possible for a client to discover which features are |
| 69 | available. The features themselves are described in the |
| 70 | <a href="pcrebuild.html"><b>pcrebuild</b></a> |
| 71 | page. Documentation about building PCRE for various operating systems can be |
| 72 | found in the <b>README</b> and <b>NON-UNIX-USE</b> files in the source |
| 73 | distribution. |
| 74 | </P> |
| 75 | <P> |
| 76 | The library contains a number of undocumented internal functions and data |
| 77 | tables that are used by more than one of the exported external functions, but |
| 78 | which are not intended for use by external callers. Their names all begin with |
| 79 | "_pcre_", which hopefully will not provoke any name clashes. In some |
| 80 | environments, it is possible to control which external symbols are exported |
| 81 | when a shared library is built, and in these cases the undocumented symbols are |
| 82 | not exported. |
| 83 | </P> |
| 84 | <br><a name="SEC2" href="#TOC1">USER DOCUMENTATION</a><br> |
| 85 | <P> |
| 86 | The user documentation for PCRE comprises a number of different sections. In |
| 87 | the "man" format, each of these is a separate "man page". In the HTML format, |
| 88 | each is a separate page, linked from the index page. In the plain text format, |
| 89 | all the sections, except the <b>pcredemo</b> section, are concatenated, for ease |
| 90 | of searching. The sections are as follows: |
| 91 | <pre> |
| 92 | pcre this document |
| 93 | pcre-config show PCRE installation configuration information |
| 94 | pcreapi details of PCRE's native C API |
| 95 | pcrebuild options for building PCRE |
| 96 | pcrecallout details of the callout feature |
| 97 | pcrecompat discussion of Perl compatibility |
| 98 | pcrecpp details of the C++ wrapper |
| 99 | pcredemo a demonstration C program that uses PCRE |
| 100 | pcregrep description of the <b>pcregrep</b> command |
| 101 | pcrejit discussion of the just-in-time optimization support |
| 102 | pcrelimits details of size and other limits |
| 103 | pcrematching discussion of the two matching algorithms |
| 104 | pcrepartial details of the partial matching facility |
| 105 | pcrepattern syntax and semantics of supported regular expressions |
| 106 | pcreperform discussion of performance issues |
| 107 | pcreposix the POSIX-compatible C API |
| 108 | pcreprecompile details of saving and re-using precompiled patterns |
| 109 | pcresample discussion of the pcredemo program |
| 110 | pcrestack discussion of stack usage |
| 111 | pcresyntax quick syntax reference |
| 112 | pcretest description of the <b>pcretest</b> testing command |
| 113 | pcreunicode discussion of Unicode and UTF-8 support |
| 114 | </pre> |
| 115 | In addition, in the "man" and HTML formats, there is a short page for each |
| 116 | C library function, listing its arguments and results. |
| 117 | </P> |
| 118 | <br><a name="SEC3" href="#TOC1">AUTHOR</a><br> |
| 119 | <P> |
| 120 | Philip Hazel |
| 121 | <br> |
| 122 | University Computing Service |
| 123 | <br> |
| 124 | Cambridge CB2 3QH, England. |
| 125 | <br> |
| 126 | </P> |
| 127 | <P> |
| 128 | Putting an actual email address here seems to have been a spam magnet, so I've |
| 129 | taken it away. If you want to email me, use my two initials, followed by the |
| 130 | two digits 10, at the domain cam.ac.uk. |
| 131 | </P> |
| 132 | <br><a name="SEC4" href="#TOC1">REVISION</a><br> |
| 133 | <P> |
| 134 | Last updated: 24 August 2011 |
| 135 | <br> |
| 136 | Copyright © 1997-2011 University of Cambridge. |
| 137 | <br> |
| 138 | <p> |
| 139 | Return to the <a href="index.html">PCRE index page</a>. |
| 140 | </p> |