version 1.1.1.2, 2012/02/21 23:50:25
|
version 1.1.1.4, 2013/07/22 08:25:56
|
Line 1
|
Line 1
|
.TH PCRE 3 | .TH PCRE 3 "13 May 2013" "PCRE 8.33" |
.SH NAME |
.SH NAME |
PCRE - Perl-compatible regular expressions |
PCRE - Perl-compatible regular expressions |
.SH INTRODUCTION |
.SH INTRODUCTION |
Line 18 UTF-8 strings), and a second library that supports 16-
|
Line 18 UTF-8 strings), and a second library that supports 16-
|
built. The majority of the work to make this possible was done by Zoltan |
built. The majority of the work to make this possible was done by Zoltan |
Herczeg. |
Herczeg. |
.P |
.P |
The two libraries contain identical sets of functions, except that the names in | Starting with release 8.32 it is possible to compile a third separate PCRE |
the 16-bit library start with \fBpcre16_\fP instead of \fBpcre_\fP. To avoid | library that supports 32-bit character strings (including UTF-32 strings). The |
over-complication and reduce the documentation maintenance load, most of the | build process allows any combination of the 8-, 16- and 32-bit libraries. The |
documentation describes the 8-bit library, with the differences for the 16-bit | work to make this possible was done by Christian Persch. |
library described separately in the | .P |
| The three libraries contain identical sets of functions, except that the names |
| in the 16-bit library start with \fBpcre16_\fP instead of \fBpcre_\fP, and the |
| names in the 32-bit library start with \fBpcre32_\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 and 32-bit libraries described separately in the |
.\" HREF |
.\" HREF |
\fBpcre16\fP |
\fBpcre16\fP |
|
and |
|
.\" HREF |
|
\fBpcre32\fP |
.\" |
.\" |
page. References to functions or structures of the form \fIpcre[16]_xxx\fP | pages. References to functions or structures of the form \fIpcre[16|32]_xxx\fP |
should be read as meaning "\fIpcre_xxx\fP when using the 8-bit library and | should be read as meaning "\fIpcre_xxx\fP when using the 8-bit library, |
\fIpcre16_xxx\fP when using the 16-bit library". | \fIpcre16_xxx\fP when using the 16-bit library, or \fIpcre32_xxx\fP when using |
| the 32-bit library". |
.P |
.P |
The current implementation of PCRE corresponds approximately with Perl 5.12, |
The current implementation of PCRE corresponds approximately with Perl 5.12, |
including support for UTF-8/16 encoded strings and Unicode general category | including support for UTF-8/16/32 encoded strings and Unicode general category |
properties. However, UTF-8/16 and Unicode support has to be explicitly enabled; | properties. However, UTF-8/16/32 and Unicode support has to be explicitly |
it is not the default. The Unicode tables correspond to Unicode release 6.0.0. | enabled; it is not the default. The Unicode tables correspond to Unicode |
| release 6.2.0. |
.P |
.P |
In addition to the Perl-compatible matching function, PCRE contains an |
In addition to the Perl-compatible matching function, PCRE contains an |
alternative function that matches the same compiled patterns in a different |
alternative function that matches the same compiled patterns in a different |
Line 57 in the \fIContrib\fP directory at the primary FTP site
|
Line 68 in the \fIContrib\fP directory at the primary FTP site
|
.\" HTML <a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre"> |
.\" HTML <a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre"> |
.\" </a> |
.\" </a> |
ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre |
ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre |
|
.\" |
.P |
.P |
Details of exactly which Perl regular expression features are and are not |
Details of exactly which Perl regular expression features are and are not |
supported by PCRE are given in separate documents. See the |
supported by PCRE are given in separate documents. See the |
Line 84 available. The features themselves are described in th
|
Line 96 available. The features themselves are described in th
|
\fBpcrebuild\fP |
\fBpcrebuild\fP |
.\" |
.\" |
page. Documentation about building PCRE for various operating systems can be |
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 | found in the |
distribution. | .\" HTML <a href="README.txt"> |
| .\" </a> |
| \fBREADME\fP |
| .\" |
| and |
| .\" HTML <a href="NON-AUTOTOOLS-BUILD.txt"> |
| .\" </a> |
| \fBNON-AUTOTOOLS_BUILD\fP |
| .\" |
| files in the source distribution. |
.P |
.P |
The libraries contains a number of undocumented internal functions and data |
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 |
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 |
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 | "_pcre_" or "_pcre16_" or "_pcre32_", which hopefully will not provoke any name |
some environments, it is possible to control which external symbols are | clashes. In some environments, it is possible to control which external symbols |
exported when a shared library is built, and in these cases the undocumented | are exported when a shared library is built, and in these cases the |
symbols are not exported. | undocumented symbols are not exported. |
. |
. |
. |
. |
|
.SH "SECURITY CONSIDERATIONS" |
|
.rs |
|
.sp |
|
If you are using PCRE in a non-UTF application that permits users to supply |
|
arbitrary patterns for compilation, you should be aware of a feature that |
|
allows users to turn on UTF support from within a pattern, provided that PCRE |
|
was built with UTF support. For example, an 8-bit pattern that begins with |
|
"(*UTF8)" or "(*UTF)" turns on UTF-8 mode, which interprets patterns and |
|
subjects as strings of UTF-8 characters instead of individual 8-bit characters. |
|
This causes both the pattern and any data against which it is matched to be |
|
checked for UTF-8 validity. If the data string is very long, such a check might |
|
use sufficiently many resources as to cause your application to lose |
|
performance. |
|
.P |
|
One way of guarding against this possibility is to use the |
|
\fBpcre_fullinfo()\fP function to check the compiled pattern's options for UTF. |
|
Alternatively, from release 8.33, you can set the PCRE_NEVER_UTF option at |
|
compile time. This causes an compile time error if a pattern contains a |
|
UTF-setting sequence. |
|
.P |
|
If your application is one that supports UTF, be aware that validity checking |
|
can take time. If the same data string is to be matched many times, you can use |
|
the PCRE_NO_UTF[8|16|32]_CHECK option for the second and subsequent matches to |
|
save redundant checks. |
|
.P |
|
Another way that performance can be hit is by running a pattern that has a very |
|
large search tree against a string that will never match. Nested unlimited |
|
repeats in a pattern are a common example. PCRE provides some protection |
|
against this: see the PCRE_EXTRA_MATCH_LIMIT feature in the |
|
.\" HREF |
|
\fBpcreapi\fP |
|
.\" |
|
page. |
|
. |
|
. |
.SH "USER DOCUMENTATION" |
.SH "USER DOCUMENTATION" |
.rs |
.rs |
.sp |
.sp |
Line 106 all the sections, except the \fBpcredemo\fP section, a
|
Line 162 all the sections, except the \fBpcredemo\fP section, a
|
of searching. The sections are as follows: |
of searching. The sections are as follows: |
.sp |
.sp |
pcre this document |
pcre this document |
pcre16 details of the 16-bit library |
|
pcre-config show PCRE installation configuration information |
pcre-config show PCRE installation configuration information |
|
pcre16 details of the 16-bit library |
|
pcre32 details of the 32-bit library |
pcreapi details of PCRE's native C API |
pcreapi details of PCRE's native C API |
pcrebuild options for building PCRE | pcrebuild building PCRE |
pcrecallout details of the callout feature |
pcrecallout details of the callout feature |
pcrecompat discussion of Perl compatibility |
pcrecompat discussion of Perl compatibility |
pcrecpp details of the C++ wrapper for the 8-bit library |
pcrecpp details of the C++ wrapper for the 8-bit library |
Line 129 of searching. The sections are as follows:
|
Line 186 of searching. The sections are as follows:
|
pcrestack discussion of stack usage |
pcrestack discussion of stack usage |
pcresyntax quick syntax reference |
pcresyntax quick syntax reference |
pcretest description of the \fBpcretest\fP testing command |
pcretest description of the \fBpcretest\fP testing command |
pcreunicode discussion of Unicode and UTF-8/16 support | pcreunicode discussion of Unicode and UTF-8/16/32 support |
.sp |
.sp |
In addition, in the "man" and HTML formats, there is a short page for each |
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. | C library function, listing its arguments and results. |
. |
. |
. |
. |
.SH AUTHOR |
.SH AUTHOR |
Line 153 two digits 10, at the domain cam.ac.uk.
|
Line 210 two digits 10, at the domain cam.ac.uk.
|
.rs |
.rs |
.sp |
.sp |
.nf |
.nf |
Last updated: 10 January 2012 | Last updated: 13 May 2013 |
Copyright (c) 1997-2012 University of Cambridge. | Copyright (c) 1997-2013 University of Cambridge. |
.fi |
.fi |