-----------------------------------------------------------------------------
This file contains a concatenation of the PCRE man pages, converted to plain
text format for ease of searching with a text editor, or for use on systems
that do not have a man page processor. The small individual files that give
synopses of each function in the library have not been included. There are
separate text files for the pcregrep and pcretest commands.
-----------------------------------------------------------------------------
PCRE(3) PCRE(3)
NAME
PCRE - Perl-compatible regular expressions
INTRODUCTION
The PCRE library is a set of functions that implement regular expres-
sion pattern matching using the same syntax and semantics as Perl, with
just a few differences. (Certain features that appeared in Python and
PCRE before they appeared in Perl are also available using the Python
syntax.)
The current implementation of PCRE (release 7.x) corresponds approxi-
mately with Perl 5.10, 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 5.0.0.
In addition to the Perl-compatible matching function, PCRE contains an
alternative matching 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 pcrematching page.
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 pcrecpp page has details
of this interface. Other people's contributions can be found in the
Contrib directory at the primary FTP site, which is:
ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre
Details of exactly which Perl regular expression features are and are
not supported by PCRE are given in separate documents. See the pcrepat-
tern and pcrecompat pages. There is a syntax summary in the pcresyntax
page.
Some features of PCRE can be included, excluded, or changed when the
library is built. The pcre_config() function makes it possible for a
client to discover which features are available. The features them-
selves are described in the pcrebuild page. Documentation about build-
ing PCRE for various operating systems can be found in the README file
in the source distribution.
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.
USER DOCUMENTATION
The user documentation for PCRE comprises a number of different sec-
tions. 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 are concatenated, for ease
of searching. The sections are as follows:
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
pcregrep description of the pcregrep command
pcrematching discussion of the two matching algorithms
pcrepartial details of the partial matching facility
pcrepattern syntax and semantics of supported
regular expressions
pcresyntax quick syntax reference
pcreperform discussion of performance issues
pcreposix the POSIX-compatible C API
pcreprecompile details of saving and re-using precompiled patterns
pcresample discussion of the sample program
pcrestack discussion of stack usage
pcretest description of the pcretest testing command
In addition, in the "man" and HTML formats, there is a short page for
each C library function, listing its arguments and results.
LIMITATIONS
There are some size limitations in PCRE but it is hoped that they will
never in practice be relevant.
The maximum length of a compiled pattern is 65539 (sic) bytes if PCRE
is compiled with the default internal linkage size of 2. If you want to
process regular expressions that are truly enormous, you can compile
PCRE with an internal linkage size of 3 or 4 (see the README file in
the source distribution and the pcrebuild documentation for details).
In these cases the limit is substantially larger. However, the speed
of execution is slower.
All values in repeating quantifiers must be less than 65536.
There is no limit to the number of parenthesized subpatterns, but there
can be no more than 65535 capturing subpatterns.
The maximum length of name for a named subpattern is 32 characters, and
the maximum number of named subpatterns is 10000.
The maximum length of a subject string is the largest positive number
that an integer variable can hold. However, when using the traditional
matching function, PCRE uses recursion to handle subpatterns and indef-
inite repetition. This means that the available stack space may limit
the size of a subject string that can be processed by certain patterns.
For a discussion of stack issues, see the pcrestack documentation.
UTF-8 AND UNICODE PROPERTY SUPPORT
From release 3.3, PCRE has had some support for character strings
encoded in the UTF-8 format. For release 4.0 this was greatly extended
to cover most common requirements, and in release 5.0 additional sup-
port for Unicode general category properties was added.
In order process UTF-8 strings, you must build PCRE to include UTF-8
support in the code, and, in addition, you must call pcre_compile()
with the PCRE_UTF8 option flag. When you do this, both the pattern and
any subject strings that are matched against it are treated as UTF-8
strings instead of just strings of bytes.
If you compile PCRE with UTF-8 support, but do not use it at run time,
the library will be a bit bigger, but the additional run time overhead
is limited to testing the PCRE_UTF8 flag occasionally, so should not be
very big.
If PCRE is built with Unicode character property support (which implies
UTF-8 support), the escape sequences \p{..}, \P{..}, and \X are sup-
ported. The available properties that can be tested are limited to the
general category properties such as Lu for an upper case letter or Nd
for a decimal number, the Unicode script names such as Arabic or Han,
and the derived properties Any and L&. A full list is gi
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php-5.2.6.tar.gz (2000个子文件)
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memleak.awk 513B
opcodeDoc.awk 507B
conffix.awk 506B
htaccessfix.awk 492B
scan_makefile_in.awk 410B
print_include.awk 122B
builddef.bat 296B
EngineSelect.bat 175B
mksbcc32.bat 52B
buildconf.bat 51B
cvsclean.bat 50B
Makefile.bcc32 1KB
Makefile.bcc32 808B
Makefile.bcc32 318B
config.h.bcc32 317B
Makefile.bcc32 236B
rules.mak.bcc32 182B
test1pix.bmp 58B
buildconf 1KB
buildconf 676B
buildconf 676B
buildconf 91B
003.txt.bz2 126B
004_1.txt.bz2 125B
004_2.txt.bz2 123B
parse_date.c 455KB
zend_language_scanner.c 235KB
btree.c 212KB
pcre_compile.c 193KB
zend_language_parser.c 190KB
basic_functions.c 167KB
soap.c 163KB
pgsql.c 161KB
vdbe.c 153KB
php_reflection.c 151KB
pcre_exec.c 147KB
exif.c 142KB
vdbe.c 140KB
pager.c 139KB
regcomp.c 139KB
gd.c 138KB
zend_compile.c 137KB
array.c 137KB
lemon.c 136KB
php_imap.c 133KB
test1.c 129KB
parse.c 129KB
mbstring.c 128KB
parse.c 127KB
string.c 126KB
ming.c 120KB
regparse.c 118KB
gdfontg.c 113KB
select.c 113KB
php_fbsql.c 112KB
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php_encoding.c 109KB
gdfontl.c 108KB
php_sdl.c 108KB
build.c 106KB
openssl.c 105KB
spl_iterators.c 101KB
php_odbc.c 100KB
where.c 96KB
gd.c 95KB
regexec.c 92KB
os_unix.c 86KB
zend_API.c 84KB
sqlite.c 82KB
php_date.c 81KB
gdfontmb.c 79KB
select.c 79KB
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