doc/html/pcre.html

<html>
<head>
<title>pcre specification</title>
</head>
<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 &copy; 1997-2011 University of Cambridge.
<br>
<p>
Return to the <a href="index.html">PCRE index page</a>.
</p>
1	nigel	63	<html>
2			<head>
3			<title>pcre specification</title>
4			</head>
5			<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6	nigel	75	<h1>pcre man page</h1>
7			<p>
8			Return to the <a href="index.html">PCRE index page</a>.
9			</p>
10	ph10	111	<p>
11	nigel	75	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	ph10	111	<br>
15	nigel	63	<ul>
16	nigel	75	<li><a name="TOC1" href="#SEC1">INTRODUCTION</a>
17	nigel	63	<li><a name="TOC2" href="#SEC2">USER DOCUMENTATION</a>
18	ph10	678	<li><a name="TOC3" href="#SEC3">AUTHOR</a>
19			<li><a name="TOC4" href="#SEC4">REVISION</a>
20	nigel	63	</ul>
21	nigel	75	<br><a name="SEC1" href="#TOC1">INTRODUCTION</a><br>
22	nigel	63	<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	ph10	461	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	nigel	63	</P>
30			<P>
31	ph10	572	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	ph10	654	is not the default. The Unicode tables correspond to Unicode release 6.0.0.
35	nigel	93	</P>
36			<P>
37			In addition to the Perl-compatible matching function, PCRE contains an
38	ph10	461	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	nigel	77	<a href="pcrematching.html"><b>pcrematching</b></a>
42			page.
43			</P>
44			<P>
45	nigel	75	PCRE is written in C and released as a C library. A number of people have
46	nigel	77	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	nigel	75	<a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre">ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre</a>
53	nigel	63	</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	ph10	208	pages. There is a syntax summary in the
61			<a href="pcresyntax.html"><b>pcresyntax</b></a>
62			page.
63	nigel	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	nigel	75	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	ph10	461	found in the <b>README</b> and <b>NON-UNIX-USE</b> files in the source
73			distribution.
74	nigel	63	</P>
75	nigel	77	<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	nigel	83	"_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	nigel	77	</P>
84	nigel	63	<br><a name="SEC2" href="#TOC1">USER DOCUMENTATION</a><br>
85			<P>
86	nigel	75	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	ph10	429	all the sections, except the <b>pcredemo</b> section, are concatenated, for ease
90			of searching. The sections are as follows:
91	nigel	63	<pre>
92			pcre this document
93	ph10	153	pcre-config show PCRE installation configuration information
94	nigel	77	pcreapi details of PCRE's native C API
95	nigel	63	pcrebuild options for building PCRE
96			pcrecallout details of the callout feature
97			pcrecompat discussion of Perl compatibility
98	nigel	77	pcrecpp details of the C++ wrapper
99	ph10	429	pcredemo a demonstration C program that uses PCRE
100	nigel	63	pcregrep description of the <b>pcregrep</b> command
101	ph10	691	pcrejit discussion of the just-in-time optimization support
102			pcrelimits details of size and other limits
103	nigel	77	pcrematching discussion of the two matching algorithms
104	nigel	75	pcrepartial details of the partial matching facility
105			pcrepattern syntax and semantics of supported regular expressions
106	nigel	63	pcreperform discussion of performance issues
107	nigel	77	pcreposix the POSIX-compatible C API
108	nigel	75	pcreprecompile details of saving and re-using precompiled patterns
109	ph10	429	pcresample discussion of the pcredemo program
110	nigel	91	pcrestack discussion of stack usage
111	ph10	461	pcresyntax quick syntax reference
112	nigel	75	pcretest description of the <b>pcretest</b> testing command
113	ph10	691	pcreunicode discussion of Unicode and UTF-8 support
114	nigel	75	</pre>
115	nigel	63	In addition, in the "man" and HTML formats, there is a short page for each
116	nigel	77	C library function, listing its arguments and results.
117	nigel	63	</P>
118	ph10	678	<br><a name="SEC3" href="#TOC1">AUTHOR</a><br>
119	nigel	63	<P>
120	nigel	77	Philip Hazel
121	nigel	63	<br>
122	ph10	99	University Computing Service
123	nigel	63	<br>
124	nigel	93	Cambridge CB2 3QH, England.
125	ph10	99	<br>
126	nigel	77	</P>
127			<P>
128			Putting an actual email address here seems to have been a spam magnet, so I've
129	ph10	153	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	ph10	99	</P>
132	ph10	678	<br><a name="SEC4" href="#TOC1">REVISION</a><br>
133	ph10	99	<P>
134	ph10	678	Last updated: 24 August 2011
135	nigel	63	<br>
136	ph10	654	Copyright © 1997-2011 University of Cambridge.
137	ph10	99	<br>
138	nigel	75	<p>
139			Return to the <a href="index.html">PCRE index page</a>.
140			</p>
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