trunk/doc/pcre.3

.TH PCRE 3 "10 January 2012" "PCRE 8.30"
.SH NAME
PCRE - Perl-compatible regular expressions
.SH INTRODUCTION
.rs
.sp
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
Starting with release 8.30, it is possible to compile two separate PCRE
libraries: the original, which supports 8-bit character strings (including
UTF-8 strings), and a second library that supports 16-bit character strings
(including UTF-16 strings). The build process allows either one or both to be
built. The majority of the work to make this possible was done by Zoltan
Herczeg.
.P
The two libraries contain identical sets of functions, except that the names in
the 16-bit library start with \fBpcre16_\fP instead of \fBpcre_\fP. To avoid
over-complication and reduce the documentation maintenance load, most of the
documentation describes the 8-bit library, with the differences for the 16-bit
library described separately in the
.\" HREF
\fBpcre16\fP
.\"
page. References to functions or structures of the form \fIpcre[16]_xxx\fP
should be read as meaning "\fIpcre_xxx\fP when using the 8-bit library and
\fIpcre16_xxx\fP when using the 16-bit library".
.P
The current implementation of PCRE corresponds approximately with Perl 5.12,
including support for UTF-8/16 encoded strings and Unicode general category
properties. However, UTF-8/16 and Unicode support has to be explicitly enabled;
it is not the default. The Unicode tables correspond to Unicode release 6.0.0.
.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
.\" HREF
\fBpcrematching\fP
.\"
page.
.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 for the 8-bit library. This is now
included as part of the PCRE distribution. The
.\" HREF
\fBpcrecpp\fP
.\"
page has details of this interface. Other people's contributions can be found
in the \fIContrib\fP directory at the primary FTP site, which is:
.sp
.\" HTML <a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre">
.\" </a>
ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre
.P
Details of exactly which Perl regular expression features are and are not
supported by PCRE are given in separate documents. See the
.\" HREF
\fBpcrepattern\fP
.\"
and
.\" HREF
\fBpcrecompat\fP
.\"
pages. There is a syntax summary in the
.\" HREF
\fBpcresyntax\fP
.\"
page.
.P
Some features of PCRE can be included, excluded, or changed when the library is
built. The
.\" HREF
\fBpcre_config()\fP
.\"
function makes it possible for a client to discover which features are
available. The features themselves are described in the
.\" HREF
\fBpcrebuild\fP
.\"
page. Documentation about building PCRE for various operating systems can be
found in the \fBREADME\fP and \fBNON-UNIX-USE\fP files in the source
distribution.
.P
The libraries 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_" or "_pcre16_", 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.
.
.
.SH "USER DOCUMENTATION"
.rs
.sp
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 \fBpcredemo\fP section, are concatenated, for ease
of searching. The sections are as follows:
.sp
  pcre              this document
  pcre16            details of the 16-bit library
  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 for the 8-bit library
  pcredemo          a demonstration C program that uses PCRE
  pcregrep          description of the \fBpcregrep\fP command (8-bit only)
  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
.\" JOIN
  pcrepattern       syntax and semantics of supported
                      regular expressions
  pcreperform       discussion of performance issues
  pcreposix         the POSIX-compatible C API for the 8-bit library
  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 \fBpcretest\fP testing command
  pcreunicode       discussion of Unicode and UTF-8/16 support
.sp
In addition, in the "man" and HTML formats, there is a short page for each
8-bit C library function, listing its arguments and results.
.
.
.SH AUTHOR
.rs
.sp
.nf
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
.fi
.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.
.
.
.SH REVISION
.rs
.sp
.nf
Last updated: 10 January 2012
Copyright (c) 1997-2012 University of Cambridge.
.fi
1	ph10	954	.TH PCRE 3 "10 January 2012" "PCRE 8.30"
2	nigel	41	.SH NAME
3	nigel	63	PCRE - Perl-compatible regular expressions
4	nigel	75	.SH INTRODUCTION
5	nigel	63	.rs
6			.sp
7	nigel	41	The PCRE library is a set of functions that implement regular expression
8	nigel	63	pattern matching using the same syntax and semantics as Perl, with just a few
9	ph10	456	differences. Some features that appeared in Python and PCRE before they
10			appeared in Perl are also available using the Python syntax, there is some
11			support for one or two .NET and Oniguruma syntax items, and there is an option
12			for requesting some minor changes that give better JavaScript compatibility.
13	nigel	75	.P
14	ph10	903	Starting with release 8.30, it is possible to compile two separate PCRE
15	ph10	846	libraries: the original, which supports 8-bit character strings (including
16			UTF-8 strings), and a second library that supports 16-bit character strings
17			(including UTF-16 strings). The build process allows either one or both to be
18	ph10	903	built. The majority of the work to make this possible was done by Zoltan
19	ph10	846	Herczeg.
20			.P
21			The two libraries contain identical sets of functions, except that the names in
22			the 16-bit library start with \fBpcre16_\fP instead of \fBpcre_\fP. To avoid
23			over-complication and reduce the documentation maintenance load, most of the
24			documentation describes the 8-bit library, with the differences for the 16-bit
25			library described separately in the
26			.\" HREF
27			\fBpcre16\fP
28			.\"
29	ph10	903	page. References to functions or structures of the form \fIpcre[16]_xxx\fP
30			should be read as meaning "\fIpcre_xxx\fP when using the 8-bit library and
31	ph10	861	\fIpcre16_xxx\fP when using the 16-bit library".
32	ph10	846	.P
33	ph10	572	The current implementation of PCRE corresponds approximately with Perl 5.12,
34	ph10	846	including support for UTF-8/16 encoded strings and Unicode general category
35			properties. However, UTF-8/16 and Unicode support has to be explicitly enabled;
36			it is not the default. The Unicode tables correspond to Unicode release 6.0.0.
37	nigel	93	.P
38			In addition to the Perl-compatible matching function, PCRE contains an
39	ph10	456	alternative function that matches the same compiled patterns in a different
40			way. In certain circumstances, the alternative function has some advantages.
41			For a discussion of the two matching algorithms, see the
42	nigel	77	.\" HREF
43			\fBpcrematching\fP
44			.\"
45			page.
46			.P
47	nigel	75	PCRE is written in C and released as a C library. A number of people have
48	nigel	77	written wrappers and interfaces of various kinds. In particular, Google Inc.
49	ph10	846	have provided a comprehensive C++ wrapper for the 8-bit library. This is now
50			included as part of the PCRE distribution. The
51	nigel	77	.\" HREF
52			\fBpcrecpp\fP
53			.\"
54			page has details of this interface. Other people's contributions can be found
55	ph10	583	in the \fIContrib\fP directory at the primary FTP site, which is:
56	nigel	75	.sp
57	nigel	63	.\" HTML <a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre">
58			.\" </a>
59			ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre
60	nigel	75	.P
61	nigel	63	Details of exactly which Perl regular expression features are and are not
62			supported by PCRE are given in separate documents. See the
63			.\" HREF
64	ph10	583	\fBpcrepattern\fP
65	nigel	63	.\"
66			and
67			.\" HREF
68	ph10	583	\fBpcrecompat\fP
69	nigel	63	.\"
70	ph10	208	pages. There is a syntax summary in the
71			.\" HREF
72	ph10	583	\fBpcresyntax\fP
73	ph10	208	.\"
74			page.
75	nigel	75	.P
76	nigel	63	Some features of PCRE can be included, excluded, or changed when the library is
77			built. The
78			.\" HREF
79	ph10	583	\fBpcre_config()\fP
80	nigel	63	.\"
81			function makes it possible for a client to discover which features are
82	nigel	75	available. The features themselves are described in the
83			.\" HREF
84			\fBpcrebuild\fP
85			.\"
86			page. Documentation about building PCRE for various operating systems can be
87	ph10	456	found in the \fBREADME\fP and \fBNON-UNIX-USE\fP files in the source
88			distribution.
89	nigel	77	.P
90	ph10	846	The libraries contains a number of undocumented internal functions and data
91	nigel	77	tables that are used by more than one of the exported external functions, but
92			which are not intended for use by external callers. Their names all begin with
93	ph10	846	"_pcre_" or "_pcre16_", which hopefully will not provoke any name clashes. In
94			some environments, it is possible to control which external symbols are
95			exported when a shared library is built, and in these cases the undocumented
96			symbols are not exported.
97	nigel	75	.
98			.
99			.SH "USER DOCUMENTATION"
100	nigel	63	.rs
101			.sp
102	nigel	75	The user documentation for PCRE comprises a number of different sections. In
103			the "man" format, each of these is a separate "man page". In the HTML format,
104			each is a separate page, linked from the index page. In the plain text format,
105	ph10	429	all the sections, except the \fBpcredemo\fP section, are concatenated, for ease
106			of searching. The sections are as follows:
107	nigel	75	.sp
108	nigel	63	pcre this document
109	ph10	903	pcre16 details of the 16-bit library
110	ph10	153	pcre-config show PCRE installation configuration information
111	nigel	77	pcreapi details of PCRE's native C API
112	nigel	63	pcrebuild options for building PCRE
113			pcrecallout details of the callout feature
114			pcrecompat discussion of Perl compatibility
115	ph10	846	pcrecpp details of the C++ wrapper for the 8-bit library
116	ph10	429	pcredemo a demonstration C program that uses PCRE
117	ph10	846	pcregrep description of the \fBpcregrep\fP command (8-bit only)
118	ph10	691	pcrejit discussion of the just-in-time optimization support
119			pcrelimits details of size and other limits
120	nigel	77	pcrematching discussion of the two matching algorithms
121	nigel	75	pcrepartial details of the partial matching facility
122			.\" JOIN
123	nigel	63	pcrepattern syntax and semantics of supported
124			regular expressions
125			pcreperform discussion of performance issues
126	ph10	846	pcreposix the POSIX-compatible C API for the 8-bit library
127	nigel	75	pcreprecompile details of saving and re-using precompiled patterns
128	ph10	429	pcresample discussion of the pcredemo program
129	nigel	91	pcrestack discussion of stack usage
130	ph10	456	pcresyntax quick syntax reference
131	nigel	75	pcretest description of the \fBpcretest\fP testing command
132	ph10	846	pcreunicode discussion of Unicode and UTF-8/16 support
133	nigel	75	.sp
134	nigel	63	In addition, in the "man" and HTML formats, there is a short page for each
135	ph10	846	8-bit C library function, listing its arguments and results.
136	nigel	75	.
137			.
138	nigel	41	.SH AUTHOR
139	nigel	63	.rs
140			.sp
141	ph10	99	.nf
142	nigel	77	Philip Hazel
143	ph10	99	University Computing Service
144	nigel	93	Cambridge CB2 3QH, England.
145	ph10	99	.fi
146	nigel	77	.P
147			Putting an actual email address here seems to have been a spam magnet, so I've
148	ph10	153	taken it away. If you want to email me, use my two initials, followed by the
149			two digits 10, at the domain cam.ac.uk.
150	ph10	99	.
151			.
152			.SH REVISION
153			.rs
154	nigel	75	.sp
155	ph10	99	.nf
156	ph10	861	Last updated: 10 January 2012
157	ph10	846	Copyright (c) 1997-2012 University of Cambridge.
158	ph10	99	.fi
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svn:eol-style	native
svn:keywords	"Author Date Id Revision Url"