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Line 14 man page, in case the conversion went wrong.	Line 14 man page, in case the conversion went wrong.
<br>	<br>
<ul>	<ul>
<li><a name="TOC1" href="#SEC1">PCRE NATIVE API BASIC FUNCTIONS</a>	<li><a name="TOC1" href="#SEC1">PCRE NATIVE API BASIC FUNCTIONS</a>
<li><a name="TOC2" href="#SEC2">PCRE NATIVE API AUXILIARY FUNCTIONS</a>	<li><a name="TOC2" href="#SEC2">PCRE NATIVE API STRING EXTRACTION FUNCTIONS</a>
<li><a name="TOC3" href="#SEC3">PCRE NATIVE API INDIRECTED FUNCTIONS</a>	<li><a name="TOC3" href="#SEC3">PCRE NATIVE API AUXILIARY FUNCTIONS</a>
<li><a name="TOC4" href="#SEC4">PCRE API OVERVIEW</a>	<li><a name="TOC4" href="#SEC4">PCRE NATIVE API INDIRECTED FUNCTIONS</a>
<li><a name="TOC5" href="#SEC5">NEWLINES</a>	<li><a name="TOC5" href="#SEC5">PCRE 8-BIT AND 16-BIT LIBRARIES</a>
<li><a name="TOC6" href="#SEC6">MULTITHREADING</a>	<li><a name="TOC6" href="#SEC6">PCRE API OVERVIEW</a>
<li><a name="TOC7" href="#SEC7">SAVING PRECOMPILED PATTERNS FOR LATER USE</a>	<li><a name="TOC7" href="#SEC7">NEWLINES</a>
<li><a name="TOC8" href="#SEC8">CHECKING BUILD-TIME OPTIONS</a>	<li><a name="TOC8" href="#SEC8">MULTITHREADING</a>
<li><a name="TOC9" href="#SEC9">COMPILING A PATTERN</a>	<li><a name="TOC9" href="#SEC9">SAVING PRECOMPILED PATTERNS FOR LATER USE</a>
<li><a name="TOC10" href="#SEC10">COMPILATION ERROR CODES</a>	<li><a name="TOC10" href="#SEC10">CHECKING BUILD-TIME OPTIONS</a>
<li><a name="TOC11" href="#SEC11">STUDYING A PATTERN</a>	<li><a name="TOC11" href="#SEC11">COMPILING A PATTERN</a>
<li><a name="TOC12" href="#SEC12">LOCALE SUPPORT</a>	<li><a name="TOC12" href="#SEC12">COMPILATION ERROR CODES</a>
<li><a name="TOC13" href="#SEC13">INFORMATION ABOUT A PATTERN</a>	<li><a name="TOC13" href="#SEC13">STUDYING A PATTERN</a>
<li><a name="TOC14" href="#SEC14">OBSOLETE INFO FUNCTION</a>	<li><a name="TOC14" href="#SEC14">LOCALE SUPPORT</a>
<li><a name="TOC15" href="#SEC15">REFERENCE COUNTS</a>	<li><a name="TOC15" href="#SEC15">INFORMATION ABOUT A PATTERN</a>
<li><a name="TOC16" href="#SEC16">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</a>	<li><a name="TOC16" href="#SEC16">REFERENCE COUNTS</a>
<li><a name="TOC17" href="#SEC17">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a>	<li><a name="TOC17" href="#SEC17">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</a>
<li><a name="TOC18" href="#SEC18">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a>	<li><a name="TOC18" href="#SEC18">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a>
<li><a name="TOC19" href="#SEC19">DUPLICATE SUBPATTERN NAMES</a>	<li><a name="TOC19" href="#SEC19">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a>
<li><a name="TOC20" href="#SEC20">FINDING ALL POSSIBLE MATCHES</a>	<li><a name="TOC20" href="#SEC20">DUPLICATE SUBPATTERN NAMES</a>
<li><a name="TOC21" href="#SEC21">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a>	<li><a name="TOC21" href="#SEC21">FINDING ALL POSSIBLE MATCHES</a>
<li><a name="TOC22" href="#SEC22">SEE ALSO</a>	<li><a name="TOC22" href="#SEC22">OBTAINING AN ESTIMATE OF STACK USAGE</a>
<li><a name="TOC23" href="#SEC23">AUTHOR</a>	<li><a name="TOC23" href="#SEC23">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a>
<li><a name="TOC24" href="#SEC24">REVISION</a>	<li><a name="TOC24" href="#SEC24">SEE ALSO</a>
	<li><a name="TOC25" href="#SEC25">AUTHOR</a>
	<li><a name="TOC26" href="#SEC26">REVISION</a>
</ul>	</ul>
<br><a name="SEC1" href="#TOC1">PCRE NATIVE API BASIC FUNCTIONS</a><br>
<P>	<P>
<b>#include <pcre.h></b>	<b>#include <pcre.h></b>
</P>	</P>
	<br><a name="SEC1" href="#TOC1">PCRE NATIVE API BASIC FUNCTIONS</a><br>
<P>	<P>
<b>pcre pcre_compile(const char <i>pattern</i>, int <i>options</i>,</b>	<b>pcre pcre_compile(const char <i>pattern</i>, int <i>options</i>,</b>
<b>const char *<i>errptr</i>, int <i>erroffset</i>,</b>	<b>const char *<i>errptr</i>, int <i>erroffset</i>,</b>
Line 65 man page, in case the conversion went wrong.	Line 67 man page, in case the conversion went wrong.
<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b>	<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b>
<b>int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b>	<b>int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b>
</P>	</P>
<br><a name="SEC2" href="#TOC1">PCRE NATIVE API AUXILIARY FUNCTIONS</a><br>
<P>	<P>
<b>pcre_jit_stack *pcre_jit_stack_alloc(int <i>startsize</i>, int <i>maxsize</i>);</b>
</P>
<P>
<b>void pcre_jit_stack_free(pcre_jit_stack *<i>stack</i>);</b>
</P>
<P>
<b>void pcre_assign_jit_stack(pcre_extra *<i>extra</i>,</b>
<b>pcre_jit_callback <i>callback</i>, void *<i>data</i>);</b>
</P>
<P>
<b>int pcre_dfa_exec(const pcre <i>code</i>, const pcre_extra <i>extra</i>,</b>	<b>int pcre_dfa_exec(const pcre <i>code</i>, const pcre_extra <i>extra</i>,</b>
<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b>	<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b>
<b>int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b>	<b>int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>,</b>
<b>int *<i>workspace</i>, int <i>wscount</i>);</b>	<b>int *<i>workspace</i>, int <i>wscount</i>);</b>
</P>	</P>
	<br><a name="SEC2" href="#TOC1">PCRE NATIVE API STRING EXTRACTION FUNCTIONS</a><br>
<P>	<P>
<b>int pcre_copy_named_substring(const pcre *<i>code</i>,</b>	<b>int pcre_copy_named_substring(const pcre *<i>code</i>,</b>
<b>const char <i>subject</i>, int <i>ovector</i>,</b>	<b>const char <i>subject</i>, int <i>ovector</i>,</b>
Line 122 man page, in case the conversion went wrong.	Line 114 man page, in case the conversion went wrong.
<P>	<P>
<b>void pcre_free_substring_list(const char **<i>stringptr</i>);</b>	<b>void pcre_free_substring_list(const char **<i>stringptr</i>);</b>
</P>	</P>
	<br><a name="SEC3" href="#TOC1">PCRE NATIVE API AUXILIARY FUNCTIONS</a><br>
<P>	<P>
	<b>pcre_jit_stack *pcre_jit_stack_alloc(int <i>startsize</i>, int <i>maxsize</i>);</b>
	</P>
	<P>
	<b>void pcre_jit_stack_free(pcre_jit_stack *<i>stack</i>);</b>
	</P>
	<P>
	<b>void pcre_assign_jit_stack(pcre_extra *<i>extra</i>,</b>
	<b>pcre_jit_callback <i>callback</i>, void *<i>data</i>);</b>
	</P>
	<P>
<b>const unsigned char *pcre_maketables(void);</b>	<b>const unsigned char *pcre_maketables(void);</b>
</P>	</P>
<P>	<P>
Line 130 man page, in case the conversion went wrong.	Line 133 man page, in case the conversion went wrong.
<b>int <i>what</i>, void *<i>where</i>);</b>	<b>int <i>what</i>, void *<i>where</i>);</b>
</P>	</P>
<P>	<P>
<b>int pcre_info(const pcre <i>code</i>, int <i>optptr</i>, int</b>
<b>*<i>firstcharptr</i>);</b>
</P>
<P>
<b>int pcre_refcount(pcre *<i>code</i>, int <i>adjust</i>);</b>	<b>int pcre_refcount(pcre *<i>code</i>, int <i>adjust</i>);</b>
</P>	</P>
<P>	<P>
<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b>	<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b>
</P>	</P>
<P>	<P>
<b>char *pcre_version(void);</b>	<b>const char *pcre_version(void);</b>
</P>	</P>
<br><a name="SEC3" href="#TOC1">PCRE NATIVE API INDIRECTED FUNCTIONS</a><br>
<P>	<P>
	<b>int pcre_pattern_to_host_byte_order(pcre *<i>code</i>,</b>
	<b>pcre_extra <i>extra</i>, const unsigned char <i>tables</i>);</b>
	</P>
	<br><a name="SEC4" href="#TOC1">PCRE NATIVE API INDIRECTED FUNCTIONS</a><br>
	<P>
<b>void (pcre_malloc)(size_t);</b>	<b>void (pcre_malloc)(size_t);</b>
</P>	</P>
<P>	<P>
Line 158 man page, in case the conversion went wrong.	Line 161 man page, in case the conversion went wrong.
<P>	<P>
<b>int (pcre_callout)(pcre_callout_block );</b>	<b>int (pcre_callout)(pcre_callout_block );</b>
</P>	</P>
<br><a name="SEC4" href="#TOC1">PCRE API OVERVIEW</a><br>	<br><a name="SEC5" href="#TOC1">PCRE 8-BIT AND 16-BIT LIBRARIES</a><br>
<P>	<P>
	From release 8.30, PCRE can be compiled as a library for handling 16-bit
	character strings as well as, or instead of, the original library that handles
	8-bit character strings. To avoid too much complication, this document
	describes the 8-bit versions of the functions, with only occasional references
	to the 16-bit library.
	</P>
	<P>
	The 16-bit functions operate in the same way as their 8-bit counterparts; they
	just use different data types for their arguments and results, and their names
	start with <b>pcre16_</b> instead of <b>pcre_</b>. For every option that has UTF8
	in its name (for example, PCRE_UTF8), there is a corresponding 16-bit name with
	UTF8 replaced by UTF16. This facility is in fact just cosmetic; the 16-bit
	option names define the same bit values.
	</P>
	<P>
	References to bytes and UTF-8 in this document should be read as references to
	16-bit data quantities and UTF-16 when using the 16-bit library, unless
	specified otherwise. More details of the specific differences for the 16-bit
	library are given in the
	<a href="pcre16.html"><b>pcre16</b></a>
	page.
	</P>
	<br><a name="SEC6" href="#TOC1">PCRE API OVERVIEW</a><br>
	<P>
PCRE has its own native API, which is described in this document. There are	PCRE has its own native API, which is described in this document. There are
also some wrapper functions that correspond to the POSIX regular expression	also some wrapper functions (for the 8-bit library only) that correspond to the
API, but they do not give access to all the functionality. They are described	POSIX regular expression API, but they do not give access to all the
in the	functionality. They are described in the
<a href="pcreposix.html"><b>pcreposix</b></a>	<a href="pcreposix.html"><b>pcreposix</b></a>
documentation. Both of these APIs define a set of C function calls. A C++	documentation. Both of these APIs define a set of C function calls. A C++
wrapper is also distributed with PCRE. It is documented in the	wrapper (again for the 8-bit library only) is also distributed with PCRE. It is
	documented in the
<a href="pcrecpp.html"><b>pcrecpp</b></a>	<a href="pcrecpp.html"><b>pcrecpp</b></a>
page.	page.
</P>	</P>
<P>	<P>
The native API C function prototypes are defined in the header file	The native API C function prototypes are defined in the header file
<b>pcre.h</b>, and on Unix systems the library itself is called <b>libpcre</b>.	<b>pcre.h</b>, and on Unix-like systems the (8-bit) library itself is called
It can normally be accessed by adding <b>-lpcre</b> to the command for linking	<b>libpcre</b>. It can normally be accessed by adding <b>-lpcre</b> to the
an application that uses PCRE. The header file defines the macros PCRE_MAJOR	command for linking an application that uses PCRE. The header file defines the
and PCRE_MINOR to contain the major and minor release numbers for the library.	macros PCRE_MAJOR and PCRE_MINOR to contain the major and minor release numbers
Applications can use these to include support for different releases of PCRE.	for the library. Applications can use these to include support for different
	releases of PCRE.
</P>	</P>
<P>	<P>
In a Windows environment, if you want to statically link an application program	In a Windows environment, if you want to statically link an application program
Line 244 internal tables that are generated when PCRE is built	Line 273 internal tables that are generated when PCRE is built
</P>	</P>
<P>	<P>
The function <b>pcre_fullinfo()</b> is used to find out information about a	The function <b>pcre_fullinfo()</b> is used to find out information about a
compiled pattern; <b>pcre_info()</b> is an obsolete version that returns only	compiled pattern. The function <b>pcre_version()</b> returns a pointer to a
some of the available information, but is retained for backwards compatibility.	string containing the version of PCRE and its date of release.
The function <b>pcre_version()</b> returns a pointer to a string containing the
version of PCRE and its date of release.
</P>	</P>
<P>	<P>
The function <b>pcre_refcount()</b> maintains a reference count in a data block	The function <b>pcre_refcount()</b> maintains a reference count in a data block
Line 284 points during a matching operation. Details are given	Line 311 points during a matching operation. Details are given
<a href="pcrecallout.html"><b>pcrecallout</b></a>	<a href="pcrecallout.html"><b>pcrecallout</b></a>
documentation.	documentation.
<a name="newlines"></a></P>	<a name="newlines"></a></P>
<br><a name="SEC5" href="#TOC1">NEWLINES</a><br>	<br><a name="SEC7" href="#TOC1">NEWLINES</a><br>
<P>	<P>
PCRE supports five different conventions for indicating line breaks in	PCRE supports five different conventions for indicating line breaks in
strings: a single CR (carriage return) character, a single LF (linefeed)	strings: a single CR (carriage return) character, a single LF (linefeed)
Line 323 The choice of newline convention does not affect the i	Line 350 The choice of newline convention does not affect the i
the \n or \r escape sequences, nor does it affect what \R matches, which is	the \n or \r escape sequences, nor does it affect what \R matches, which is
controlled in a similar way, but by separate options.	controlled in a similar way, but by separate options.
</P>	</P>
<br><a name="SEC6" href="#TOC1">MULTITHREADING</a><br>	<br><a name="SEC8" href="#TOC1">MULTITHREADING</a><br>
<P>	<P>
The PCRE functions can be used in multi-threading applications, with the	The PCRE functions can be used in multi-threading applications, with the
proviso that the memory management functions pointed to by <b>pcre_malloc</b>,	proviso that the memory management functions pointed to by <b>pcre_malloc</b>,
Line 340 memory stack areas for each thread. See the	Line 367 memory stack areas for each thread. See the
<a href="pcrejit.html"><b>pcrejit</b></a>	<a href="pcrejit.html"><b>pcrejit</b></a>
documentation for more details.	documentation for more details.
</P>	</P>
<br><a name="SEC7" href="#TOC1">SAVING PRECOMPILED PATTERNS FOR LATER USE</a><br>	<br><a name="SEC9" href="#TOC1">SAVING PRECOMPILED PATTERNS FOR LATER USE</a><br>
<P>	<P>
The compiled form of a regular expression can be saved and re-used at a later	The compiled form of a regular expression can be saved and re-used at a later
time, possibly by a different program, and even on a host other than the one on	time, possibly by a different program, and even on a host other than the one on
which it was compiled. Details are given in the	which it was compiled. Details are given in the
<a href="pcreprecompile.html"><b>pcreprecompile</b></a>	<a href="pcreprecompile.html"><b>pcreprecompile</b></a>
documentation. However, compiling a regular expression with one version of PCRE	documentation, which includes a description of the
for use with a different version is not guaranteed to work and may cause	<b>pcre_pattern_to_host_byte_order()</b> function. However, compiling a regular
crashes.	expression with one version of PCRE for use with a different version is not
	guaranteed to work and may cause crashes.
</P>	</P>
<br><a name="SEC8" href="#TOC1">CHECKING BUILD-TIME OPTIONS</a><br>	<br><a name="SEC10" href="#TOC1">CHECKING BUILD-TIME OPTIONS</a><br>
<P>	<P>
<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b>	<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b>
</P>	</P>
Line 363 documentation has more details about these optional fe	Line 391 documentation has more details about these optional fe
<P>	<P>
The first argument for <b>pcre_config()</b> is an integer, specifying which	The first argument for <b>pcre_config()</b> is an integer, specifying which
information is required; the second argument is a pointer to a variable into	information is required; the second argument is a pointer to a variable into
which the information is placed. The following information is available:	which the information is placed. The returned value is zero on success, or the
	negative error code PCRE_ERROR_BADOPTION if the value in the first argument is
	not recognized. The following information is available:
<pre>	<pre>
PCRE_CONFIG_UTF8	PCRE_CONFIG_UTF8
</pre>	</pre>
The output is an integer that is set to one if UTF-8 support is available;	The output is an integer that is set to one if UTF-8 support is available;
otherwise it is set to zero.	otherwise it is set to zero. If this option is given to the 16-bit version of
	this function, <b>pcre16_config()</b>, the result is PCRE_ERROR_BADOPTION.
<pre>	<pre>
	PCRE_CONFIG_UTF16
	</pre>
	The output is an integer that is set to one if UTF-16 support is available;
	otherwise it is set to zero. This value should normally be given to the 16-bit
	version of this function, <b>pcre16_config()</b>. If it is given to the 8-bit
	version of this function, the result is PCRE_ERROR_BADOPTION.
	<pre>
PCRE_CONFIG_UNICODE_PROPERTIES	PCRE_CONFIG_UNICODE_PROPERTIES
</pre>	</pre>
The output is an integer that is set to one if support for Unicode character	The output is an integer that is set to one if support for Unicode character
Line 380 properties is available; otherwise it is set to zero.	Line 418 properties is available; otherwise it is set to zero.
The output is an integer that is set to one if support for just-in-time	The output is an integer that is set to one if support for just-in-time
compiling is available; otherwise it is set to zero.	compiling is available; otherwise it is set to zero.
<pre>	<pre>
	PCRE_CONFIG_JITTARGET
	</pre>
	The output is a pointer to a zero-terminated "const char *" string. If JIT
	support is available, the string contains the name of the architecture for
	which the JIT compiler is configured, for example "x86 32bit (little endian +
	unaligned)". If JIT support is not available, the result is NULL.
	<pre>
PCRE_CONFIG_NEWLINE	PCRE_CONFIG_NEWLINE
</pre>	</pre>
The output is an integer whose value specifies the default character sequence	The output is an integer whose value specifies the default character sequence
Line 399 or CRLF. The default can be overridden when a pattern	Line 444 or CRLF. The default can be overridden when a pattern
PCRE_CONFIG_LINK_SIZE	PCRE_CONFIG_LINK_SIZE
</pre>	</pre>
The output is an integer that contains the number of bytes used for internal	The output is an integer that contains the number of bytes used for internal
linkage in compiled regular expressions. The value is 2, 3, or 4. Larger values	linkage in compiled regular expressions. For the 8-bit library, the value can
allow larger regular expressions to be compiled, at the expense of slower	be 2, 3, or 4. For the 16-bit library, the value is either 2 or 4 and is still
matching. The default value of 2 is sufficient for all but the most massive	a number of bytes. The default value of 2 is sufficient for all but the most
patterns, since it allows the compiled pattern to be up to 64K in size.	massive patterns, since it allows the compiled pattern to be up to 64K in size.
	Larger values allow larger regular expressions to be compiled, at the expense
	of slower matching.
<pre>	<pre>
PCRE_CONFIG_POSIX_MALLOC_THRESHOLD	PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
</pre>	</pre>
Line 434 of recursive function calls. In this case, <b>pcre_sta	Line 481 of recursive function calls. In this case, <b>pcre_sta
<b>pcre_stack_free</b> are called to manage memory blocks on the heap, thus	<b>pcre_stack_free</b> are called to manage memory blocks on the heap, thus
avoiding the use of the stack.	avoiding the use of the stack.
</P>	</P>
<br><a name="SEC9" href="#TOC1">COMPILING A PATTERN</a><br>	<br><a name="SEC11" href="#TOC1">COMPILING A PATTERN</a><br>
<P>	<P>
<b>pcre pcre_compile(const char <i>pattern</i>, int <i>options</i>,</b>	<b>pcre pcre_compile(const char <i>pattern</i>, int <i>options</i>,</b>
<b>const char *<i>errptr</i>, int <i>erroffset</i>,</b>	<b>const char *<i>errptr</i>, int <i>erroffset</i>,</b>
Line 489 not try to free it. Normally, the offset from the star	Line 536 not try to free it. Normally, the offset from the star
byte that was being processed when the error was discovered is placed in the	byte that was being processed when the error was discovered is placed in the
variable pointed to by <i>erroffset</i>, which must not be NULL (if it is, an	variable pointed to by <i>erroffset</i>, which must not be NULL (if it is, an
immediate error is given). However, for an invalid UTF-8 string, the offset is	immediate error is given). However, for an invalid UTF-8 string, the offset is
that of the first byte of the failing character. Also, some errors are not	that of the first byte of the failing character.
detected until checks are carried out when the whole pattern has been scanned;
in these cases the offset passed back is the length of the pattern.
</P>	</P>
<P>	<P>
Note that the offset is in bytes, not characters, even in UTF-8 mode. It may	Some errors are not detected until the whole pattern has been scanned; in these
sometimes point into the middle of a UTF-8 character.	cases, the offset passed back is the length of the pattern. Note that the
	offset is in bytes, not characters, even in UTF-8 mode. It may sometimes point
	into the middle of a UTF-8 character.
</P>	</P>
<P>	<P>
If <b>pcre_compile2()</b> is used instead of <b>pcre_compile()</b>, and the	If <b>pcre_compile2()</b> is used instead of <b>pcre_compile()</b>, and the
Line 699 preceding sequences should be recognized. Setting PCRE	Line 746 preceding sequences should be recognized. Setting PCRE
that any Unicode newline sequence should be recognized. The Unicode newline	that any Unicode newline sequence should be recognized. The Unicode newline
sequences are the three just mentioned, plus the single characters VT (vertical	sequences are the three just mentioned, plus the single characters VT (vertical
tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line	tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line
separator, U+2028), and PS (paragraph separator, U+2029). The last two are	separator, U+2028), and PS (paragraph separator, U+2029). For the 8-bit
recognized only in UTF-8 mode.	library, the last two are recognized only in UTF-8 mode.
</P>	</P>
<P>	<P>
The newline setting in the options word uses three bits that are treated	The newline setting in the options word uses three bits that are treated
Line 760 with Perl. It can also be set by a (?U) option setting	Line 807 with Perl. It can also be set by a (?U) option setting
PCRE_UTF8	PCRE_UTF8
</pre>	</pre>
This option causes PCRE to regard both the pattern and the subject as strings	This option causes PCRE to regard both the pattern and the subject as strings
of UTF-8 characters instead of single-byte character strings. However, it is	of UTF-8 characters instead of single-byte strings. However, it is available
available only when PCRE is built to include UTF-8 support. If not, the use	only when PCRE is built to include UTF support. If not, the use of this option
of this option provokes an error. Details of how this option changes the	provokes an error. Details of how this option changes the behaviour of PCRE are
behaviour of PCRE are given in the	given in the
<a href="pcreunicode.html"><b>pcreunicode</b></a>	<a href="pcreunicode.html"><b>pcreunicode</b></a>
page.	page.
<pre>	<pre>
PCRE_NO_UTF8_CHECK	PCRE_NO_UTF8_CHECK
</pre>	</pre>
When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is	When PCRE_UTF8 is set, the validity of the pattern as a UTF-8
automatically checked. There is a discussion about the	string is automatically checked. There is a discussion about the
<a href="pcre.html#utf8strings">validity of UTF-8 strings</a>	<a href="pcreunicode.html#utf8strings">validity of UTF-8 strings</a>
in the main	in the
<a href="pcre.html"><b>pcre</b></a>	<a href="pcreunicode.html"><b>pcreunicode</b></a>
page. If an invalid UTF-8 sequence of bytes is found, <b>pcre_compile()</b>	page. If an invalid UTF-8 sequence is found, <b>pcre_compile()</b> returns an
returns an error. If you already know that your pattern is valid, and you want	error. If you already know that your pattern is valid, and you want to skip
to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK	this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK option.
option. When it is set, the effect of passing an invalid UTF-8 string as a	When it is set, the effect of passing an invalid UTF-8 string as a pattern is
pattern is undefined. It may cause your program to crash. Note that this option	undefined. It may cause your program to crash. Note that this option can also
can also be passed to <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>, to suppress	be passed to <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>, to suppress the
the UTF-8 validity checking of subject strings.	validity checking of subject strings.
</P>	</P>
<br><a name="SEC10" href="#TOC1">COMPILATION ERROR CODES</a><br>	<br><a name="SEC12" href="#TOC1">COMPILATION ERROR CODES</a><br>
<P>	<P>
The following table lists the error codes than may be returned by	The following table lists the error codes than may be returned by
<b>pcre_compile2()</b>, along with the error messages that may be returned by	<b>pcre_compile2()</b>, along with the error messages that may be returned by
both compiling functions. As PCRE has developed, some error codes have fallen	both compiling functions. Note that error messages are always 8-bit ASCII
out of use. To avoid confusion, they have not been re-used.	strings, even in 16-bit mode. As PCRE has developed, some error codes have
	fallen out of use. To avoid confusion, they have not been re-used.
<pre>	<pre>
0 no error	0 no error
1 \ at end of pattern	1 \ at end of pattern
Line 821 out of use. To avoid confusion, they have not been re-	Line 869 out of use. To avoid confusion, they have not been re-
29 (?R or (?[+-]digits must be followed by )	29 (?R or (?[+-]digits must be followed by )
30 unknown POSIX class name	30 unknown POSIX class name
31 POSIX collating elements are not supported	31 POSIX collating elements are not supported
32 this version of PCRE is not compiled with PCRE_UTF8 support	32 this version of PCRE is compiled without UTF support
33 [this code is not in use]	33 [this code is not in use]
34 character value in \x{...} sequence is too large	34 character value in \x{...} sequence is too large
35 invalid condition (?(0)	35 invalid condition (?(0)
Line 833 out of use. To avoid confusion, they have not been re-	Line 881 out of use. To avoid confusion, they have not been re-
41 unrecognized character after (?P	41 unrecognized character after (?P
42 syntax error in subpattern name (missing terminator)	42 syntax error in subpattern name (missing terminator)
43 two named subpatterns have the same name	43 two named subpatterns have the same name
44 invalid UTF-8 string	44 invalid UTF-8 string (specifically UTF-8)
45 support for \P, \p, and \X has not been compiled	45 support for \P, \p, and \X has not been compiled
46 malformed \P or \p sequence	46 malformed \P or \p sequence
47 unknown property name after \P or \p	47 unknown property name after \P or \p
48 subpattern name is too long (maximum 32 characters)	48 subpattern name is too long (maximum 32 characters)
49 too many named subpatterns (maximum 10000)	49 too many named subpatterns (maximum 10000)
50 [this code is not in use]	50 [this code is not in use]
51 octal value is greater than \377 (not in UTF-8 mode)	51 octal value is greater than \377 in 8-bit non-UTF-8 mode
52 internal error: overran compiling workspace	52 internal error: overran compiling workspace
53 internal error: previously-checked referenced subpattern	53 internal error: previously-checked referenced subpattern
not found	not found
Line 859 out of use. To avoid confusion, they have not been re-	Line 907 out of use. To avoid confusion, they have not been re-
65 different names for subpatterns of the same number are	65 different names for subpatterns of the same number are
not allowed	not allowed
66 (*MARK) must have an argument	66 (*MARK) must have an argument
67 this version of PCRE is not compiled with PCRE_UCP support	67 this version of PCRE is not compiled with Unicode property
	support
68 \c must be followed by an ASCII character	68 \c must be followed by an ASCII character
69 \k is not followed by a braced, angle-bracketed, or quoted name	69 \k is not followed by a braced, angle-bracketed, or quoted name
	70 internal error: unknown opcode in find_fixedlength()
	71 \N is not supported in a class
	72 too many forward references
	73 disallowed Unicode code point (>= 0xd800 && <= 0xdfff)
	74 invalid UTF-16 string (specifically UTF-16)
</pre>	</pre>
The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may	The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
be used if the limits were changed when PCRE was built.	be used if the limits were changed when PCRE was built.
<a name="studyingapattern"></a></P>	<a name="studyingapattern"></a></P>
<br><a name="SEC11" href="#TOC1">STUDYING A PATTERN</a><br>	<br><a name="SEC13" href="#TOC1">STUDYING A PATTERN</a><br>
<P>	<P>
<b>pcre_extra pcre_study(const pcre <i>code</i>, int <i>options</i></b>	<b>pcre_extra pcre_study(const pcre <i>code</i>, int <i>options</i></b>
<b>const char **<i>errptr</i>);</b>	<b>const char **<i>errptr</i>);</b>
Line 958 in a calling program via the <b>pcre_fullinfo()</b> fu	Line 1012 in a calling program via the <b>pcre_fullinfo()</b> fu
Studying a pattern is also useful for non-anchored patterns that do not have a	Studying a pattern is also useful for non-anchored patterns that do not have a
single fixed starting character. A bitmap of possible starting bytes is	single fixed starting character. A bitmap of possible starting bytes is
created. This speeds up finding a position in the subject at which to start	created. This speeds up finding a position in the subject at which to start
matching.	matching. (In 16-bit mode, the bitmap is used for 16-bit values less than 256.)
</P>	</P>
<P>	<P>
These two optimizations apply to both <b>pcre_exec()</b> and	These two optimizations apply to both <b>pcre_exec()</b> and
Line 972 to make use of these facilities in cases where matchin	Line 1026 to make use of these facilities in cases where matchin
discussion of PCRE_NO_START_OPTIMIZE	discussion of PCRE_NO_START_OPTIMIZE
<a href="#execoptions">below.</a>	<a href="#execoptions">below.</a>
<a name="localesupport"></a></P>	<a name="localesupport"></a></P>
<br><a name="SEC12" href="#TOC1">LOCALE SUPPORT</a><br>	<br><a name="SEC14" href="#TOC1">LOCALE SUPPORT</a><br>
<P>	<P>
PCRE handles caseless matching, and determines whether characters are letters,	PCRE handles caseless matching, and determines whether characters are letters,
digits, or whatever, by reference to a set of tables, indexed by character	digits, or whatever, by reference to a set of tables, indexed by character
value. When running in UTF-8 mode, this applies only to characters with codes	value. When running in UTF-8 mode, this applies only to characters
less than 128. By default, higher-valued codes never match escapes such as \w	with codes less than 128. By default, higher-valued codes never match escapes
or \d, but they can be tested with \p if PCRE is built with Unicode character	such as \w or \d, but they can be tested with \p if PCRE is built with
property support. Alternatively, the PCRE_UCP option can be set at compile	Unicode character property support. Alternatively, the PCRE_UCP option can be
time; this causes \w and friends to use Unicode property support instead of	set at compile time; this causes \w and friends to use Unicode property
built-in tables. The use of locales with Unicode is discouraged. If you are	support instead of built-in tables. The use of locales with Unicode is
handling characters with codes greater than 128, you should either use UTF-8	discouraged. If you are handling characters with codes greater than 128, you
and Unicode, or use locales, but not try to mix the two.	should either use UTF-8 and Unicode, or use locales, but not try to mix the
	two.
</P>	</P>
<P>	<P>
PCRE contains an internal set of tables that are used when the final argument	PCRE contains an internal set of tables that are used when the final argument
Line 1033 this facility could be used to match a pattern in a di	Line 1088 this facility could be used to match a pattern in a di
one in which it was compiled. Passing table pointers at run time is discussed	one in which it was compiled. Passing table pointers at run time is discussed
below in the section on matching a pattern.	below in the section on matching a pattern.
<a name="infoaboutpattern"></a></P>	<a name="infoaboutpattern"></a></P>
<br><a name="SEC13" href="#TOC1">INFORMATION ABOUT A PATTERN</a><br>	<br><a name="SEC15" href="#TOC1">INFORMATION ABOUT A PATTERN</a><br>
<P>	<P>
<b>int pcre_fullinfo(const pcre <i>code</i>, const pcre_extra <i>extra</i>,</b>	<b>int pcre_fullinfo(const pcre <i>code</i>, const pcre_extra <i>extra</i>,</b>
<b>int <i>what</i>, void *<i>where</i>);</b>	<b>int <i>what</i>, void *<i>where</i>);</b>
</P>	</P>
<P>	<P>
The <b>pcre_fullinfo()</b> function returns information about a compiled	The <b>pcre_fullinfo()</b> function returns information about a compiled
pattern. It replaces the obsolete <b>pcre_info()</b> function, which is	pattern. It replaces the <b>pcre_info()</b> function, which was removed from the
nevertheless retained for backwards compability (and is documented below).	library at version 8.30, after more than 10 years of obsolescence.
</P>	</P>
<P>	<P>
The first argument for <b>pcre_fullinfo()</b> is a pointer to the compiled	The first argument for <b>pcre_fullinfo()</b> is a pointer to the compiled
Line 1051 information is required, and the fourth argument is a	Line 1106 information is required, and the fourth argument is a
to receive the data. The yield of the function is zero for success, or one of	to receive the data. The yield of the function is zero for success, or one of
the following negative numbers:	the following negative numbers:
<pre>	<pre>
PCRE_ERROR_NULL the argument <i>code</i> was NULL	PCRE_ERROR_NULL the argument <i>code</i> was NULL
the argument <i>where</i> was NULL	the argument <i>where</i> was NULL
PCRE_ERROR_BADMAGIC the "magic number" was not found	PCRE_ERROR_BADMAGIC the "magic number" was not found
PCRE_ERROR_BADOPTION the value of <i>what</i> was invalid	PCRE_ERROR_BADENDIANNESS the pattern was compiled with different
	endianness
	PCRE_ERROR_BADOPTION the value of <i>what</i> was invalid
</pre>	</pre>
The "magic number" is placed at the start of each compiled pattern as an simple	The "magic number" is placed at the start of each compiled pattern as an simple
check against passing an arbitrary memory pointer. Here is a typical call of	check against passing an arbitrary memory pointer. The endianness error can
<b>pcre_fullinfo()</b>, to obtain the length of the compiled pattern:	occur if a compiled pattern is saved and reloaded on a different host. Here is
	a typical call of <b>pcre_fullinfo()</b>, to obtain the length of the compiled
	pattern:
<pre>	<pre>
int rc;	int rc;
size_t length;	size_t length;
Line 1092 a NULL table pointer.	Line 1151 a NULL table pointer.
<pre>	<pre>
PCRE_INFO_FIRSTBYTE	PCRE_INFO_FIRSTBYTE
</pre>	</pre>
Return information about the first byte of any matched string, for a	Return information about the first data unit of any matched string, for a
non-anchored pattern. The fourth argument should point to an <b>int</b>	non-anchored pattern. (The name of this option refers to the 8-bit library,
variable. (This option used to be called PCRE_INFO_FIRSTCHAR; the old name is	where data units are bytes.) The fourth argument should point to an <b>int</b>
still recognized for backwards compatibility.)	variable.
</P>	</P>
<P>	<P>
If there is a fixed first byte, for example, from a pattern such as	If there is a fixed first value, for example, the letter "c" from a pattern
(cat\|cow\|coyote), its value is returned. Otherwise, if either	such as (cat\|cow\|coyote), its value is returned. In the 8-bit library, the
	value is always less than 256; in the 16-bit library the value can be up to
	0xffff.
	</P>
	<P>
	If there is no fixed first value, and if either
<br>	<br>
<br>	<br>
(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch	(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
Line 1117 returned. For anchored patterns, -2 is returned.	Line 1181 returned. For anchored patterns, -2 is returned.
PCRE_INFO_FIRSTTABLE	PCRE_INFO_FIRSTTABLE
</pre>	</pre>
If the pattern was studied, and this resulted in the construction of a 256-bit	If the pattern was studied, and this resulted in the construction of a 256-bit
table indicating a fixed set of bytes for the first byte in any matching	table indicating a fixed set of values for the first data unit in any matching
string, a pointer to the table is returned. Otherwise NULL is returned. The	string, a pointer to the table is returned. Otherwise NULL is returned. The
fourth argument should point to an <b>unsigned char *</b> variable.	fourth argument should point to an <b>unsigned char *</b> variable.
<pre>	<pre>
Line 1152 argument should point to a <b>size_t</b> variable.	Line 1216 argument should point to a <b>size_t</b> variable.
<pre>	<pre>
PCRE_INFO_LASTLITERAL	PCRE_INFO_LASTLITERAL
</pre>	</pre>
Return the value of the rightmost literal byte that must exist in any matched	Return the value of the rightmost literal data unit that must exist in any
string, other than at its start, if such a byte has been recorded. The fourth	matched string, other than at its start, if such a value has been recorded. The
argument should point to an <b>int</b> variable. If there is no such byte, -1 is	fourth argument should point to an <b>int</b> variable. If there is no such
returned. For anchored patterns, a last literal byte is recorded only if it	value, -1 is returned. For anchored patterns, a last literal value is recorded
follows something of variable length. For example, for the pattern	only if it follows something of variable length. For example, for the pattern
/^a\d+z\d+/ the returned value is "z", but for /^a\dz\d/ the returned value	/^a\d+z\d+/ the returned value is "z", but for /^a\dz\d/ the returned value
is -1.	is -1.
<pre>	<pre>
Line 1164 is -1.	Line 1228 is -1.
</pre>	</pre>
If the pattern was studied and a minimum length for matching subject strings	If the pattern was studied and a minimum length for matching subject strings
was computed, its value is returned. Otherwise the returned value is -1. The	was computed, its value is returned. Otherwise the returned value is -1. The
value is a number of characters, not bytes (this may be relevant in UTF-8	value is a number of characters, which in UTF-8 mode may be different from the
mode). The fourth argument should point to an <b>int</b> variable. A	number of bytes. The fourth argument should point to an <b>int</b> variable. A
non-negative value is a lower bound to the length of any matching string. There	non-negative value is a lower bound to the length of any matching string. There
may not be any strings of that length that do actually match, but every string	may not be any strings of that length that do actually match, but every string
that does match is at least that long.	that does match is at least that long.
Line 1189 The map consists of a number of fixed-size entries. PC	Line 1253 The map consists of a number of fixed-size entries. PC
the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each	the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each
entry; both of these return an <b>int</b> value. The entry size depends on the	entry; both of these return an <b>int</b> value. The entry size depends on the
length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first	length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first
entry of the table (a pointer to <b>char</b>). The first two bytes of each entry	entry of the table. This is a pointer to <b>char</b> in the 8-bit library, where
are the number of the capturing parenthesis, most significant byte first. The	the first two bytes of each entry are the number of the capturing parenthesis,
rest of the entry is the corresponding name, zero terminated.	most significant byte first. In the 16-bit library, the pointer points to
	16-bit data units, the first of which contains the parenthesis number. The rest
	of the entry is the corresponding name, zero terminated.
</P>	</P>
<P>	<P>
The names are in alphabetical order. Duplicate names may appear if (?\| is used	The names are in alphabetical order. Duplicate names may appear if (?\| is used
Line 1207 necessarily the case because later subpatterns may hav	Line 1273 necessarily the case because later subpatterns may hav
</P>	</P>
<P>	<P>
As a simple example of the name/number table, consider the following pattern	As a simple example of the name/number table, consider the following pattern
(assume PCRE_EXTENDED is set, so white space - including newlines - is	after compilation by the 8-bit library (assume PCRE_EXTENDED is set, so white
ignored):	space - including newlines - is ignored):
<pre>	<pre>
(?<date> (?<year>(\d\d)?\d\d) - (?<month>\d\d) - (?<day>\d\d) )	(?<date> (?<year>(\d\d)?\d\d) - (?<month>\d\d) - (?<day>\d\d) )
</pre>	</pre>
Line 1258 For such patterns, the PCRE_ANCHORED bit is set in the	Line 1324 For such patterns, the PCRE_ANCHORED bit is set in the
<pre>	<pre>
PCRE_INFO_SIZE	PCRE_INFO_SIZE
</pre>	</pre>
Return the size of the compiled pattern. The fourth argument should point to a	Return the size of the compiled pattern in bytes (for both libraries). The
<b>size_t</b> variable. This value does not include the size of the <b>pcre</b>	fourth argument should point to a <b>size_t</b> variable. This value does not
structure that is returned by <b>pcre_compile()</b>. The value that is passed as	include the size of the <b>pcre</b> structure that is returned by
the argument to <b>pcre_malloc()</b> when <b>pcre_compile()</b> is getting memory	<b>pcre_compile()</b>. The value that is passed as the argument to
in which to place the compiled data is the value returned by this option plus	<b>pcre_malloc()</b> when <b>pcre_compile()</b> is getting memory in which to
the size of the <b>pcre</b> structure. Studying a compiled pattern, with or	place the compiled data is the value returned by this option plus the size of
without JIT, does not alter the value returned by this option.	the <b>pcre</b> structure. Studying a compiled pattern, with or without JIT,
	does not alter the value returned by this option.
<pre>	<pre>
PCRE_INFO_STUDYSIZE	PCRE_INFO_STUDYSIZE
</pre>	</pre>
Return the size of the data block pointed to by the <i>study_data</i> field in a	Return the size in bytes of the data block pointed to by the <i>study_data</i>
<b>pcre_extra</b> block. If <b>pcre_extra</b> is NULL, or there is no study data,	field in a <b>pcre_extra</b> block. If <b>pcre_extra</b> is NULL, or there is no
zero is returned. The fourth argument should point to a <b>size_t</b> variable.	study data, zero is returned. The fourth argument should point to a
The <i>study_data</i> field is set by <b>pcre_study()</b> to record information	<b>size_t</b> variable. The <i>study_data</i> field is set by <b>pcre_study()</b>
that will speed up matching (see the section entitled	to record information that will speed up matching (see the section entitled
<a href="#studyingapattern">"Studying a pattern"</a>	<a href="#studyingapattern">"Studying a pattern"</a>
above). The format of the <i>study_data</i> block is private, but its length	above). The format of the <i>study_data</i> block is private, but its length
is made available via this option so that it can be saved and restored (see the	is made available via this option so that it can be saved and restored (see the
<a href="pcreprecompile.html"><b>pcreprecompile</b></a>	<a href="pcreprecompile.html"><b>pcreprecompile</b></a>
documentation for details).	documentation for details).
</P>	</P>
<br><a name="SEC14" href="#TOC1">OBSOLETE INFO FUNCTION</a><br>	<br><a name="SEC16" href="#TOC1">REFERENCE COUNTS</a><br>
<P>	<P>
<b>int pcre_info(const pcre <i>code</i>, int <i>optptr</i>, int</b>
<b>*<i>firstcharptr</i>);</b>
</P>
<P>
The <b>pcre_info()</b> function is now obsolete because its interface is too
restrictive to return all the available data about a compiled pattern. New
programs should use <b>pcre_fullinfo()</b> instead. The yield of
<b>pcre_info()</b> is the number of capturing subpatterns, or one of the
following negative numbers:
<pre>
PCRE_ERROR_NULL the argument <i>code</i> was NULL
PCRE_ERROR_BADMAGIC the "magic number" was not found
</pre>
If the <i>optptr</i> argument is not NULL, a copy of the options with which the
pattern was compiled is placed in the integer it points to (see
PCRE_INFO_OPTIONS above).
</P>
<P>
If the pattern is not anchored and the <i>firstcharptr</i> argument is not NULL,
it is used to pass back information about the first character of any matched
string (see PCRE_INFO_FIRSTBYTE above).
</P>
<br><a name="SEC15" href="#TOC1">REFERENCE COUNTS</a><br>
<P>
<b>int pcre_refcount(pcre *<i>code</i>, int <i>adjust</i>);</b>	<b>int pcre_refcount(pcre *<i>code</i>, int <i>adjust</i>);</b>
</P>	</P>
<P>	<P>
Line 1327 Except when it is zero, the reference count is not cor	Line 1370 Except when it is zero, the reference count is not cor
pattern is compiled on one host and then transferred to a host whose byte-order	pattern is compiled on one host and then transferred to a host whose byte-order
is different. (This seems a highly unlikely scenario.)	is different. (This seems a highly unlikely scenario.)
</P>	</P>
<br><a name="SEC16" href="#TOC1">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</a><br>	<br><a name="SEC17" href="#TOC1">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</a><br>
<P>	<P>
<b>int pcre_exec(const pcre <i>code</i>, const pcre_extra <i>extra</i>,</b>	<b>int pcre_exec(const pcre <i>code</i>, const pcre_extra <i>extra</i>,</b>
<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b>	<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b>
Line 1392 fields (not necessarily in this order):	Line 1435 fields (not necessarily in this order):
const unsigned char *<i>tables</i>;	const unsigned char *<i>tables</i>;
unsigned char **<i>mark</i>;	unsigned char **<i>mark</i>;
</pre>	</pre>
	In the 16-bit version of this structure, the <i>mark</i> field has type
	"PCRE_UCHAR16 **".
	</P>
	<P>
The <i>flags</i> field is a bitmap that specifies which of the other fields	The <i>flags</i> field is a bitmap that specifies which of the other fields
are set. The flag bits are:	are set. The flag bits are:
<pre>	<pre>
Line 1482 documentation for a discussion of saving compiled patt	Line 1529 documentation for a discussion of saving compiled patt
</P>	</P>
<P>	<P>
If PCRE_EXTRA_MARK is set in the <i>flags</i> field, the <i>mark</i> field must	If PCRE_EXTRA_MARK is set in the <i>flags</i> field, the <i>mark</i> field must
be set to point to a <b>char *</b> variable. If the pattern contains any	be set to point to a suitable variable. If the pattern contains any
backtracking control verbs such as (*MARK:NAME), and the execution ends up with	backtracking control verbs such as (*MARK:NAME), and the execution ends up with
a name to pass back, a pointer to the name string (zero terminated) is placed	a name to pass back, a pointer to the name string (zero terminated) is placed
in the variable pointed to by the <i>mark</i> field. The names are within the	in the variable pointed to by the <i>mark</i> field. The names are within the
compiled pattern; if you wish to retain such a name you must copy it before	compiled pattern; if you wish to retain such a name you must copy it before
freeing the memory of a compiled pattern. If there is no name to pass back, the	freeing the memory of a compiled pattern. If there is no name to pass back, the
variable pointed to by the <i>mark</i> field set to NULL. For details of the	variable pointed to by the <i>mark</i> field is set to NULL. For details of the
backtracking control verbs, see the section entitled	backtracking control verbs, see the section entitled
<a href="pcrepattern#backtrackcontrol">"Backtracking control"</a>	<a href="pcrepattern#backtrackcontrol">"Backtracking control"</a>
in the	in the
Line 1671 string is automatically checked when <b>pcre_exec()</b	Line 1718 string is automatically checked when <b>pcre_exec()</b
The value of <i>startoffset</i> is also checked to ensure that it points to the	The value of <i>startoffset</i> is also checked to ensure that it points to the
start of a UTF-8 character. There is a discussion about the validity of UTF-8	start of a UTF-8 character. There is a discussion about the validity of UTF-8
strings in the	strings in the
<a href="pcre.html#utf8strings">section on UTF-8 support</a>	<a href="pcreunicode.html"><b>pcreunicode</b></a>
in the main	page. If an invalid sequence of bytes is found, <b>pcre_exec()</b> returns the
<a href="pcre.html"><b>pcre</b></a>	error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is a
page. If an invalid UTF-8 sequence of bytes is found, <b>pcre_exec()</b> returns	truncated character at the end of the subject, PCRE_ERROR_SHORTUTF8. In both
the error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is	cases, information about the precise nature of the error may also be returned
a truncated UTF-8 character at the end of the subject, PCRE_ERROR_SHORTUTF8. In	(see the descriptions of these errors in the section entitled \fIError return
both cases, information about the precise nature of the error may also be	values from\fP <b>pcre_exec()</b>
returned (see the descriptions of these errors in the section entitled \fIError
return values from\fP <b>pcre_exec()</b>
<a href="#errorlist">below).</a>	<a href="#errorlist">below).</a>
If <i>startoffset</i> contains a value that does not point to the start of a	If <i>startoffset</i> contains a value that does not point to the start of a
UTF-8 character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is	UTF-8 character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
Line 1691 checks for performance reasons, you can set the PCRE_N	Line 1736 checks for performance reasons, you can set the PCRE_N
calling <b>pcre_exec()</b>. You might want to do this for the second and	calling <b>pcre_exec()</b>. You might want to do this for the second and
subsequent calls to <b>pcre_exec()</b> if you are making repeated calls to find	subsequent calls to <b>pcre_exec()</b> if you are making repeated calls to find
all the matches in a single subject string. However, you should be sure that	all the matches in a single subject string. However, you should be sure that
the value of <i>startoffset</i> points to the start of a UTF-8 character (or the	the value of <i>startoffset</i> points to the start of a character (or the end
end of the subject). When PCRE_NO_UTF8_CHECK is set, the effect of passing an	of the subject). When PCRE_NO_UTF8_CHECK is set, the effect of passing an
invalid UTF-8 string as a subject or an invalid value of <i>startoffset</i> is	invalid string as a subject or an invalid value of <i>startoffset</i> is
undefined. Your program may crash.	undefined. Your program may crash.
<pre>	<pre>
PCRE_PARTIAL_HARD	PCRE_PARTIAL_HARD
Line 1728 The string to be matched by <b>pcre_exec()</b>	Line 1773 The string to be matched by <b>pcre_exec()</b>
</b><br>	</b><br>
<P>	<P>
The subject string is passed to <b>pcre_exec()</b> as a pointer in	The subject string is passed to <b>pcre_exec()</b> as a pointer in
<i>subject</i>, a length (in bytes) in <i>length</i>, and a starting byte offset	<i>subject</i>, a length in bytes in <i>length</i>, and a starting byte offset
in <i>startoffset</i>. If this is negative or greater than the length of the	in <i>startoffset</i>. If this is negative or greater than the length of the
subject, <b>pcre_exec()</b> returns PCRE_ERROR_BADOFFSET. When the starting	subject, <b>pcre_exec()</b> returns PCRE_ERROR_BADOFFSET. When the starting
offset is zero, the search for a match starts at the beginning of the subject,	offset is zero, the search for a match starts at the beginning of the subject,
Line 2027 PCRE_STUDY_JIT_COMPILE option is being matched, but th	Line 2072 PCRE_STUDY_JIT_COMPILE option is being matched, but th
the just-in-time processing stack is not large enough. See the	the just-in-time processing stack is not large enough. See the
<a href="pcrejit.html"><b>pcrejit</b></a>	<a href="pcrejit.html"><b>pcrejit</b></a>
documentation for more details.	documentation for more details.
	<pre>
	PCRE_ERROR_BADMODE (-28)
	</pre>
	This error is given if a pattern that was compiled by the 8-bit library is
	passed to a 16-bit library function, or vice versa.
	<pre>
	PCRE_ERROR_BADENDIANNESS (-29)
	</pre>
	This error is given if a pattern that was compiled and saved is reloaded on a
	host with different endianness. The utility function
	<b>pcre_pattern_to_host_byte_order()</b> can be used to convert such a pattern
	so that it runs on the new host.
</P>	</P>
<P>	<P>
Error numbers -16 to -20 and -22 are not used by <b>pcre_exec()</b>.	Error numbers -16 to -20 and -22 are not used by <b>pcre_exec()</b>.
Line 2035 Error numbers -16 to -20 and -22 are not used by <b>pc	Line 2092 Error numbers -16 to -20 and -22 are not used by <b>pc
Reason codes for invalid UTF-8 strings	Reason codes for invalid UTF-8 strings
</b><br>	</b><br>
<P>	<P>
	This section applies only to the 8-bit library. The corresponding information
	for the 16-bit library is given in the
	<a href="pcre16.html"><b>pcre16</b></a>
	page.
	</P>
	<P>
When <b>pcre_exec()</b> returns either PCRE_ERROR_BADUTF8 or	When <b>pcre_exec()</b> returns either PCRE_ERROR_BADUTF8 or
PCRE_ERROR_SHORTUTF8, and the size of the output vector (<i>ovecsize</i>) is at	PCRE_ERROR_SHORTUTF8, and the size of the output vector (<i>ovecsize</i>) is at
least 2, the offset of the start of the invalid UTF-8 character is placed in	least 2, the offset of the start of the invalid UTF-8 character is placed in
Line 2104 character.	Line 2167 character.
The first byte of a character has the value 0xfe or 0xff. These values can	The first byte of a character has the value 0xfe or 0xff. These values can
never occur in a valid UTF-8 string.	never occur in a valid UTF-8 string.
</P>	</P>
<br><a name="SEC17" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a><br>	<br><a name="SEC18" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a><br>
<P>	<P>
<b>int pcre_copy_substring(const char <i>subject</i>, int <i>ovector</i>,</b>	<b>int pcre_copy_substring(const char <i>subject</i>, int <i>ovector</i>,</b>
<b>int <i>stringcount</i>, int <i>stringnumber</i>, char *<i>buffer</i>,</b>	<b>int <i>stringcount</i>, int <i>stringnumber</i>, char *<i>buffer</i>,</b>
Line 2199 linked via a special interface to another programming	Line 2262 linked via a special interface to another programming
<b>pcre_free</b> directly; it is for these cases that the functions are	<b>pcre_free</b> directly; it is for these cases that the functions are
provided.	provided.
</P>	</P>
<br><a name="SEC18" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a><br>	<br><a name="SEC19" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a><br>
<P>	<P>
<b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b>	<b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b>
<b>const char *<i>name</i>);</b>	<b>const char *<i>name</i>);</b>
Line 2263 names are not included in the compiled code. The match	Line 2326 names are not included in the compiled code. The match
numbers. For this reason, the use of different names for subpatterns of the	numbers. For this reason, the use of different names for subpatterns of the
same number causes an error at compile time.	same number causes an error at compile time.
</P>	</P>
<br><a name="SEC19" href="#TOC1">DUPLICATE SUBPATTERN NAMES</a><br>	<br><a name="SEC20" href="#TOC1">DUPLICATE SUBPATTERN NAMES</a><br>
<P>	<P>
<b>int pcre_get_stringtable_entries(const pcre *<i>code</i>,</b>	<b>int pcre_get_stringtable_entries(const pcre *<i>code</i>,</b>
<b>const char <i>name</i>, char <i>first</i>, char *<i>last</i>);</b>	<b>const char <i>name</i>, char <i>first</i>, char *<i>last</i>);</b>
Line 2301 described above in the section entitled <i>Information	Line 2364 described above in the section entitled <i>Information
Given all the relevant entries for the name, you can extract each of their	Given all the relevant entries for the name, you can extract each of their
numbers, and hence the captured data, if any.	numbers, and hence the captured data, if any.
</P>	</P>
<br><a name="SEC20" href="#TOC1">FINDING ALL POSSIBLE MATCHES</a><br>	<br><a name="SEC21" href="#TOC1">FINDING ALL POSSIBLE MATCHES</a><br>
<P>	<P>
The traditional matching function uses a similar algorithm to Perl, which stops	The traditional matching function uses a similar algorithm to Perl, which stops
when it finds the first match, starting at a given point in the subject. If you	when it finds the first match, starting at a given point in the subject. If you
Line 2319 When your callout function is called, extract and save	Line 2382 When your callout function is called, extract and save
substring. Then return 1, which forces <b>pcre_exec()</b> to backtrack and try	substring. Then return 1, which forces <b>pcre_exec()</b> to backtrack and try
other alternatives. Ultimately, when it runs out of matches, <b>pcre_exec()</b>	other alternatives. Ultimately, when it runs out of matches, <b>pcre_exec()</b>
will yield PCRE_ERROR_NOMATCH.	will yield PCRE_ERROR_NOMATCH.
	</P>
	<br><a name="SEC22" href="#TOC1">OBTAINING AN ESTIMATE OF STACK USAGE</a><br>
	<P>
	Matching certain patterns using <b>pcre_exec()</b> can use a lot of process
	stack, which in certain environments can be rather limited in size. Some users
	find it helpful to have an estimate of the amount of stack that is used by
	<b>pcre_exec()</b>, to help them set recursion limits, as described in the
	<a href="pcrestack.html"><b>pcrestack</b></a>
	documentation. The estimate that is output by <b>pcretest</b> when called with
	the <b>-m</b> and <b>-C</b> options is obtained by calling <b>pcre_exec</b> with
	the values NULL, NULL, NULL, -999, and -999 for its first five arguments.
	</P>
	<P>
	Normally, if its first argument is NULL, <b>pcre_exec()</b> immediately returns
	the negative error code PCRE_ERROR_NULL, but with this special combination of
	arguments, it returns instead a negative number whose absolute value is the
	approximate stack frame size in bytes. (A negative number is used so that it is
	clear that no match has happened.) The value is approximate because in some
	cases, recursive calls to <b>pcre_exec()</b> occur when there are one or two
	additional variables on the stack.
	</P>
	<P>
	If PCRE has been compiled to use the heap instead of the stack for recursion,
	the value returned is the size of each block that is obtained from the heap.
<a name="dfamatch"></a></P>	<a name="dfamatch"></a></P>
<br><a name="SEC21" href="#TOC1">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a><br>	<br><a name="SEC23" href="#TOC1">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a><br>
<P>	<P>
<b>int pcre_dfa_exec(const pcre <i>code</i>, const pcre_extra <i>extra</i>,</b>	<b>int pcre_dfa_exec(const pcre <i>code</i>, const pcre_extra <i>extra</i>,</b>
<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b>	<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b>
Line 2495 recursively, using private vectors for <i>ovector</i>	Line 2582 recursively, using private vectors for <i>ovector</i>
error is given if the output vector is not large enough. This should be	error is given if the output vector is not large enough. This should be
extremely rare, as a vector of size 1000 is used.	extremely rare, as a vector of size 1000 is used.
</P>	</P>
<br><a name="SEC22" href="#TOC1">SEE ALSO</a><br>	<br><a name="SEC24" href="#TOC1">SEE ALSO</a><br>
<P>	<P>
<b>pcrebuild</b>(3), <b>pcrecallout</b>(3), <b>pcrecpp(3)</b>(3),	<b>pcre16</b>(3), <b>pcrebuild</b>(3), <b>pcrecallout</b>(3), <b>pcrecpp(3)</b>(3),
<b>pcrematching</b>(3), <b>pcrepartial</b>(3), <b>pcreposix</b>(3),	<b>pcrematching</b>(3), <b>pcrepartial</b>(3), <b>pcreposix</b>(3),
<b>pcreprecompile</b>(3), <b>pcresample</b>(3), <b>pcrestack</b>(3).	<b>pcreprecompile</b>(3), <b>pcresample</b>(3), <b>pcrestack</b>(3).
</P>	</P>
<br><a name="SEC23" href="#TOC1">AUTHOR</a><br>	<br><a name="SEC25" href="#TOC1">AUTHOR</a><br>
<P>	<P>
Philip Hazel	Philip Hazel
<br>	<br>
Line 2510 University Computing Service	Line 2597 University Computing Service
Cambridge CB2 3QH, England.	Cambridge CB2 3QH, England.
<br>	<br>
</P>	</P>
<br><a name="SEC24" href="#TOC1">REVISION</a><br>	<br><a name="SEC26" href="#TOC1">REVISION</a><br>
<P>	<P>
Last updated: 02 December 2011	Last updated: 21 January 2012
<br>	<br>
Copyright © 1997-2011 University of Cambridge.	Copyright © 1997-2012 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>.

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