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Revision 1055 - (show annotations)
Tue Oct 16 15:53:30 2012 UTC (7 years, 1 month ago) by chpe
File size: 6777 byte(s)
pcre32: Add 32-bit library

Create libpcre32 that operates on 32-bit characters (UTF-32).

This turned out to be surprisingly simple after the UTF-16 support
was introduced; mostly just extra ifdefs and adjusting and adding
some tests.
1 .TH PCRE 3 "10 January 2012" "PCRE 8.30"
3 PCRE - Perl-compatible regular expressions
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
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 Starting with release 8.FIXME, it is possible to compile a third separate PCRE
22 library, which supports 32-bit character strings (including
23 UTF-32 strings). The build process allows any set of the 8-, 16- and 32-bit
24 libraries.
25 .P
26 The three libraries contain identical sets of functions, except that the names in
27 the 16-bit library start with \fBpcre16_\fP instead of \fBpcre_\fP, and the names
28 in the 32-bit library start with \fBpcre32_\fP instead of \fBpcre_\fP. To avoid
29 over-complication and reduce the documentation maintenance load, most of the
30 documentation describes the 8-bit library, with the differences for the 16-bit
31 and 32-bit library described separately in the
32 .\" HREF
33 \fBpcre16\fP
34 or
35 .\" HREF
36 \fBpcre32\fP
37 .\"
38 page. References to functions or structures of the form \fIpcre[16|32]_xxx\fP
39 should be read as meaning "\fIpcre_xxx\fP when using the 8-bit library and
40 \fIpcre16_xxx\fP when using the 16-bit library and
41 \fIpcre32_xxx\fP when using the 32-bit library".
42 .P
43 The current implementation of PCRE corresponds approximately with Perl 5.12,
44 including support for UTF-8/16 encoded strings and Unicode general category
45 properties. However, UTF-8/16 and Unicode support has to be explicitly enabled;
46 it is not the default. The Unicode tables correspond to Unicode release 6.2.0.
47 .P
48 In addition to the Perl-compatible matching function, PCRE contains an
49 alternative function that matches the same compiled patterns in a different
50 way. In certain circumstances, the alternative function has some advantages.
51 For a discussion of the two matching algorithms, see the
52 .\" HREF
53 \fBpcrematching\fP
54 .\"
55 page.
56 .P
57 PCRE is written in C and released as a C library. A number of people have
58 written wrappers and interfaces of various kinds. In particular, Google Inc.
59 have provided a comprehensive C++ wrapper for the 8-bit library. This is now
60 included as part of the PCRE distribution. The
61 .\" HREF
62 \fBpcrecpp\fP
63 .\"
64 page has details of this interface. Other people's contributions can be found
65 in the \fIContrib\fP directory at the primary FTP site, which is:
66 .sp
67 .\" HTML <a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre">
68 .\" </a>
69 ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre
70 .P
71 Details of exactly which Perl regular expression features are and are not
72 supported by PCRE are given in separate documents. See the
73 .\" HREF
74 \fBpcrepattern\fP
75 .\"
76 and
77 .\" HREF
78 \fBpcrecompat\fP
79 .\"
80 pages. There is a syntax summary in the
81 .\" HREF
82 \fBpcresyntax\fP
83 .\"
84 page.
85 .P
86 Some features of PCRE can be included, excluded, or changed when the library is
87 built. The
88 .\" HREF
89 \fBpcre_config()\fP
90 .\"
91 function makes it possible for a client to discover which features are
92 available. The features themselves are described in the
93 .\" HREF
94 \fBpcrebuild\fP
95 .\"
96 page. Documentation about building PCRE for various operating systems can be
97 found in the \fBREADME\fP and \fBNON-UNIX-USE\fP files in the source
98 distribution.
99 .P
100 The libraries contains a number of undocumented internal functions and data
101 tables that are used by more than one of the exported external functions, but
102 which are not intended for use by external callers. Their names all begin with
103 "_pcre_" or "_pcre16_" or "_pcre32_", which hopefully will not provoke any name
104 clashes. In some environments, it is possible to control which external symbols
105 are exported when a shared library is built, and in these cases the undocumented
106 symbols are not exported.
107 .
108 .
110 .rs
111 .sp
112 The user documentation for PCRE comprises a number of different sections. In
113 the "man" format, each of these is a separate "man page". In the HTML format,
114 each is a separate page, linked from the index page. In the plain text format,
115 all the sections, except the \fBpcredemo\fP section, are concatenated, for ease
116 of searching. The sections are as follows:
117 .sp
118 pcre this document
119 pcre16 details of the 16-bit library
120 pcre32 details of the 32-bit library
121 pcre-config show PCRE installation configuration information
122 pcreapi details of PCRE's native C API
123 pcrebuild options for building PCRE
124 pcrecallout details of the callout feature
125 pcrecompat discussion of Perl compatibility
126 pcrecpp details of the C++ wrapper for the 8-bit library
127 pcredemo a demonstration C program that uses PCRE
128 pcregrep description of the \fBpcregrep\fP command (8-bit only)
129 pcrejit discussion of the just-in-time optimization support
130 pcrelimits details of size and other limits
131 pcrematching discussion of the two matching algorithms
132 pcrepartial details of the partial matching facility
133 .\" JOIN
134 pcrepattern syntax and semantics of supported
135 regular expressions
136 pcreperform discussion of performance issues
137 pcreposix the POSIX-compatible C API for the 8-bit library
138 pcreprecompile details of saving and re-using precompiled patterns
139 pcresample discussion of the pcredemo program
140 pcrestack discussion of stack usage
141 pcresyntax quick syntax reference
142 pcretest description of the \fBpcretest\fP testing command
143 pcreunicode discussion of Unicode and UTF-8/16/32 support
144 .sp
145 In addition, in the "man" and HTML formats, there is a short page for each
146 8-bit C library function, listing its arguments and results.
147 .
148 .
150 .rs
151 .sp
152 .nf
153 Philip Hazel
154 University Computing Service
155 Cambridge CB2 3QH, England.
156 .fi
157 .P
158 Putting an actual email address here seems to have been a spam magnet, so I've
159 taken it away. If you want to email me, use my two initials, followed by the
160 two digits 10, at the domain cam.ac.uk.
161 .
162 .
164 .rs
165 .sp
166 .nf
167 Last updated: 10 January 2012
168 Copyright (c) 1997-2012 University of Cambridge.
169 .fi


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