Annotation of embedaddon/pcre/doc/pcre.3, revision 1.1.1.2
1.1 misho 1: .TH PCRE 3
2: .SH NAME
3: PCRE - Perl-compatible regular expressions
4: .SH INTRODUCTION
5: .rs
6: .sp
7: The PCRE library is a set of functions that implement regular expression
8: pattern matching using the same syntax and semantics as Perl, with just a few
9: 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: .P
1.1.1.2 ! misho 14: Starting with release 8.30, it is possible to compile two separate PCRE
! 15: 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: built. The majority of the work to make this possible was done by Zoltan
! 19: 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: 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: \fIpcre16_xxx\fP when using the 16-bit library".
! 32: .P
1.1 misho 33: The current implementation of PCRE corresponds approximately with Perl 5.12,
1.1.1.2 ! misho 34: 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.
1.1 misho 37: .P
38: In addition to the Perl-compatible matching function, PCRE contains an
39: 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: .\" HREF
43: \fBpcrematching\fP
44: .\"
45: page.
46: .P
47: PCRE is written in C and released as a C library. A number of people have
48: written wrappers and interfaces of various kinds. In particular, Google Inc.
1.1.1.2 ! misho 49: have provided a comprehensive C++ wrapper for the 8-bit library. This is now
! 50: included as part of the PCRE distribution. The
1.1 misho 51: .\" HREF
52: \fBpcrecpp\fP
53: .\"
54: page has details of this interface. Other people's contributions can be found
55: in the \fIContrib\fP directory at the primary FTP site, which is:
56: .sp
57: .\" 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: .P
61: 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: \fBpcrepattern\fP
65: .\"
66: and
67: .\" HREF
68: \fBpcrecompat\fP
69: .\"
70: pages. There is a syntax summary in the
71: .\" HREF
72: \fBpcresyntax\fP
73: .\"
74: page.
75: .P
76: Some features of PCRE can be included, excluded, or changed when the library is
77: built. The
78: .\" HREF
79: \fBpcre_config()\fP
80: .\"
81: function makes it possible for a client to discover which features are
82: 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: found in the \fBREADME\fP and \fBNON-UNIX-USE\fP files in the source
88: distribution.
89: .P
1.1.1.2 ! misho 90: The libraries contains a number of undocumented internal functions and data
1.1 misho 91: 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
1.1.1.2 ! misho 93: "_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.
1.1 misho 97: .
98: .
99: .SH "USER DOCUMENTATION"
100: .rs
101: .sp
102: 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: all the sections, except the \fBpcredemo\fP section, are concatenated, for ease
106: of searching. The sections are as follows:
107: .sp
108: pcre this document
1.1.1.2 ! misho 109: pcre16 details of the 16-bit library
1.1 misho 110: pcre-config show PCRE installation configuration information
111: pcreapi details of PCRE's native C API
112: pcrebuild options for building PCRE
113: pcrecallout details of the callout feature
114: pcrecompat discussion of Perl compatibility
1.1.1.2 ! misho 115: pcrecpp details of the C++ wrapper for the 8-bit library
1.1 misho 116: pcredemo a demonstration C program that uses PCRE
1.1.1.2 ! misho 117: pcregrep description of the \fBpcregrep\fP command (8-bit only)
1.1 misho 118: pcrejit discussion of the just-in-time optimization support
119: pcrelimits details of size and other limits
120: pcrematching discussion of the two matching algorithms
121: pcrepartial details of the partial matching facility
122: .\" JOIN
123: pcrepattern syntax and semantics of supported
124: regular expressions
125: pcreperform discussion of performance issues
1.1.1.2 ! misho 126: pcreposix the POSIX-compatible C API for the 8-bit library
1.1 misho 127: pcreprecompile details of saving and re-using precompiled patterns
128: pcresample discussion of the pcredemo program
129: pcrestack discussion of stack usage
130: pcresyntax quick syntax reference
131: pcretest description of the \fBpcretest\fP testing command
1.1.1.2 ! misho 132: pcreunicode discussion of Unicode and UTF-8/16 support
1.1 misho 133: .sp
134: In addition, in the "man" and HTML formats, there is a short page for each
1.1.1.2 ! misho 135: 8-bit C library function, listing its arguments and results.
1.1 misho 136: .
137: .
138: .SH AUTHOR
139: .rs
140: .sp
141: .nf
142: Philip Hazel
143: University Computing Service
144: Cambridge CB2 3QH, England.
145: .fi
146: .P
147: Putting an actual email address here seems to have been a spam magnet, so I've
148: 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: .
151: .
152: .SH REVISION
153: .rs
154: .sp
155: .nf
1.1.1.2 ! misho 156: Last updated: 10 January 2012
! 157: Copyright (c) 1997-2012 University of Cambridge.
1.1 misho 158: .fi
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