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Line 14 man page, in case the conversion went wrong.
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<br> |
<br> |
<ul> |
<ul> |
<li><a name="TOC1" href="#SEC1">INTRODUCTION</a> |
<li><a name="TOC1" href="#SEC1">INTRODUCTION</a> |
<li><a name="TOC2" href="#SEC2">USER DOCUMENTATION</a> | <li><a name="TOC2" href="#SEC2">SECURITY CONSIDERATIONS</a> |
<li><a name="TOC3" href="#SEC3">AUTHOR</a> | <li><a name="TOC3" href="#SEC3">USER DOCUMENTATION</a> |
<li><a name="TOC4" href="#SEC4">REVISION</a> | <li><a name="TOC4" href="#SEC4">AUTHOR</a> |
| <li><a name="TOC5" href="#SEC5">REVISION</a> |
</ul> |
</ul> |
<br><a name="SEC1" href="#TOC1">INTRODUCTION</a><br> |
<br><a name="SEC1" href="#TOC1">INTRODUCTION</a><br> |
<P> |
<P> |
Line 36 built. The majority of the work to make this possible
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Line 37 built. The majority of the work to make this possible
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Herczeg. |
Herczeg. |
</P> |
</P> |
<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 <b>pcre16_</b> instead of <b>pcre_</b>. 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> |
| <P> |
| The three libraries contain identical sets of functions, except that the names |
| in the 16-bit library start with <b>pcre16_</b> instead of <b>pcre_</b>, and the |
| names in the 32-bit library start with <b>pcre32_</b> instead of <b>pcre_</b>. 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 |
<a href="pcre16.html"><b>pcre16</b></a> |
<a href="pcre16.html"><b>pcre16</b></a> |
page. References to functions or structures of the form <i>pcre[16]_xxx</i> | and |
should be read as meaning "<i>pcre_xxx</i> when using the 8-bit library and | <a href="pcre32.html"><b>pcre32</b></a> |
<i>pcre16_xxx</i> when using the 16-bit library". | pages. References to functions or structures of the form <i>pcre[16|32]_xxx</i> |
| should be read as meaning "<i>pcre_xxx</i> when using the 8-bit library, |
| <i>pcre16_xxx</i> when using the 16-bit library, or <i>pcre32_xxx</i> when using |
| the 32-bit library". |
</P> |
</P> |
<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> |
<P> |
<P> |
In addition to the Perl-compatible matching function, PCRE contains an |
In addition to the Perl-compatible matching function, PCRE contains an |
Line 88 function makes it possible for a client to discover wh
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Line 100 function makes it possible for a client to discover wh
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available. The features themselves are described in the |
available. The features themselves are described in the |
<a href="pcrebuild.html"><b>pcrebuild</b></a> |
<a href="pcrebuild.html"><b>pcrebuild</b></a> |
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 <b>README</b> and <b>NON-UNIX-USE</b> files in the source | found in the |
distribution. | <a href="README.txt"><b>README</b></a> |
| and |
| <a href="NON-AUTOTOOLS-BUILD.txt"><b>NON-AUTOTOOLS_BUILD</b></a> |
| files in the source distribution. |
</P> |
</P> |
<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. |
</P> |
</P> |
<br><a name="SEC2" href="#TOC1">USER DOCUMENTATION</a><br> | <br><a name="SEC2" href="#TOC1">SECURITY CONSIDERATIONS</a><br> |
<P> |
<P> |
|
If you are using PCRE in a non-UTF application that permits users to supply |
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arbitrary patterns for compilation, you should be aware of a feature that |
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allows users to turn on UTF support from within a pattern, provided that PCRE |
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was built with UTF support. For example, an 8-bit pattern that begins with |
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"(*UTF8)" or "(*UTF)" turns on UTF-8 mode, which interprets patterns and |
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subjects as strings of UTF-8 characters instead of individual 8-bit characters. |
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This causes both the pattern and any data against which it is matched to be |
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checked for UTF-8 validity. If the data string is very long, such a check might |
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use sufficiently many resources as to cause your application to lose |
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performance. |
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</P> |
|
<P> |
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One way of guarding against this possibility is to use the |
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<b>pcre_fullinfo()</b> function to check the compiled pattern's options for UTF. |
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Alternatively, from release 8.33, you can set the PCRE_NEVER_UTF option at |
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compile time. This causes an compile time error if a pattern contains a |
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UTF-setting sequence. |
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</P> |
|
<P> |
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If your application is one that supports UTF, be aware that validity checking |
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can take time. If the same data string is to be matched many times, you can use |
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the PCRE_NO_UTF[8|16|32]_CHECK option for the second and subsequent matches to |
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save redundant checks. |
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</P> |
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<P> |
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Another way that performance can be hit is by running a pattern that has a very |
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large search tree against a string that will never match. Nested unlimited |
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repeats in a pattern are a common example. PCRE provides some protection |
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against this: see the PCRE_EXTRA_MATCH_LIMIT feature in the |
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<a href="pcreapi.html"><b>pcreapi</b></a> |
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page. |
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</P> |
|
<br><a name="SEC3" href="#TOC1">USER DOCUMENTATION</a><br> |
|
<P> |
The user documentation for PCRE comprises a number of different sections. In |
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, |
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, |
each is a separate page, linked from the index page. In the plain text format, |
Line 109 all the sections, except the <b>pcredemo</b> section,
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Line 158 all the sections, except the <b>pcredemo</b> section,
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of searching. The sections are as follows: |
of searching. The sections are as follows: |
<pre> |
<pre> |
pcre this document |
pcre this document |
pcre16 details of the 16-bit library |
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pcre-config show PCRE installation configuration information |
pcre-config show PCRE installation configuration information |
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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 130 of searching. The sections are as follows:
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Line 180 of searching. The sections are as follows:
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pcrestack discussion of stack usage |
pcrestack discussion of stack usage |
pcresyntax quick syntax reference |
pcresyntax quick syntax reference |
pcretest description of the <b>pcretest</b> testing command |
pcretest description of the <b>pcretest</b> testing command |
pcreunicode discussion of Unicode and UTF-8/16 support | pcreunicode discussion of Unicode and UTF-8/16/32 support |
</pre> |
</pre> |
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. |
</P> |
</P> |
<br><a name="SEC3" href="#TOC1">AUTHOR</a><br> | <br><a name="SEC4" href="#TOC1">AUTHOR</a><br> |
<P> |
<P> |
Philip Hazel |
Philip Hazel |
<br> |
<br> |
Line 149 Putting an actual email address here seems to have bee
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Line 199 Putting an actual email address here seems to have bee
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taken it away. If you want to email me, use my two initials, followed by the |
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. |
two digits 10, at the domain cam.ac.uk. |
</P> |
</P> |
<br><a name="SEC4" href="#TOC1">REVISION</a><br> | <br><a name="SEC5" href="#TOC1">REVISION</a><br> |
<P> |
<P> |
Last updated: 10 January 2012 | Last updated: 13 May 2013 |
<br> |
<br> |
Copyright © 1997-2012 University of Cambridge. | Copyright © 1997-2013 University of Cambridge. |
<br> |
<br> |
<p> |
<p> |
Return to the <a href="index.html">PCRE index page</a>. |
Return to the <a href="index.html">PCRE index page</a>. |