Diff for /embedaddon/pcre/doc/html/pcreapi.html between versions 1.1 and 1.1.1.3

version 1.1, 2012/02/21 23:05:52 version 1.1.1.3, 2012/10/09 09:19:18
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 <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 &#60;pcre.h&#62;</b>  <b>#include &#60;pcre.h&#62;</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>
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 <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>
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 <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>
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 <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>
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 <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 expressionalso 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 describedPOSIX regular expression API, but they do not give access to all the
in thefunctionality. 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 thewrapper (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_MAJORcommand 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 onlycompiled 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)
 character, the two-character sequence CRLF, any of the three preceding, or any  character, the two-character sequence CRLF, any of the three preceding, or any
 Unicode newline sequence. The Unicode newline sequences are the three just  Unicode newline sequence. The Unicode newline sequences are the three just
mentioned, plus the single characters VT (vertical tab, U+000B), FF (formfeed,mentioned, plus the single characters VT (vertical tab, U+000B), FF (form feed,
 U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS  U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
 (paragraph separator, U+2029).  (paragraph separator, U+2029).
 </P>  </P>
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 PCREdocumentation, 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 valueslinkage in compiled regular expressions. For the 8-bit library, the value can
allow larger regular expressions to be compiled, at the expense of slowerbe 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 massivea 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 477  documentation). For those options that can be differen Line 524  documentation). For those options that can be differen
 the pattern, the contents of the <i>options</i> argument specifies their  the pattern, the contents of the <i>options</i> argument specifies their
 settings at the start of compilation and execution. The PCRE_ANCHORED,  settings at the start of compilation and execution. The PCRE_ANCHORED,
 PCRE_BSR_<i>xxx</i>, PCRE_NEWLINE_<i>xxx</i>, PCRE_NO_UTF8_CHECK, and  PCRE_BSR_<i>xxx</i>, PCRE_NEWLINE_<i>xxx</i>, PCRE_NO_UTF8_CHECK, and
PCRE_NO_START_OPT options can be set at the time of matching as well as atPCRE_NO_START_OPTIMIZE options can be set at the time of matching as well as at
 compile time.  compile time.
 </P>  </P>
 <P>  <P>
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 notthat 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 maySome 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 594  documentation. Line 641  documentation.
 <pre>  <pre>
   PCRE_EXTENDED    PCRE_EXTENDED
 </pre>  </pre>
If this bit is set, whitespace data characters in the pattern are totallyIf this bit is set, white space data characters in the pattern are totally
ignored except when escaped or inside a character class. Whitespace does notignored except when escaped or inside a character class. White space does not
 include the VT character (code 11). In addition, characters between an  include the VT character (code 11). In addition, characters between an
 unescaped # outside a character class and the next newline, inclusive, are also  unescaped # outside a character class and the next newline, inclusive, are also
 ignored. This is equivalent to Perl's /x option, and it can be changed within a  ignored. This is equivalent to Perl's /x option, and it can be changed within a
Line 612  happen to represent a newline do not count. Line 659  happen to represent a newline do not count.
 </P>  </P>
 <P>  <P>
 This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
Note, however, that this applies only to data characters. Whitespace charactersNote, however, that this applies only to data characters. White space characters
 may never appear within special character sequences in a pattern, for example  may never appear within special character sequences in a pattern, for example
 within the sequence (?( that introduces a conditional subpattern.  within the sequence (?( that introduces a conditional subpattern.
 <pre>  <pre>
Line 698  CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies  Line 745  CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies 
 preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies  preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
 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 (linetab, U+000B), FF (form feed, U+000C), NEL (next line, U+0085), LS (line
separator, U+2028), and PS (paragraph separator, U+2029). The last two areseparator, 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 712  other combinations may yield unused numbers and cause  Line 759  other combinations may yield unused numbers and cause 
 </P>  </P>
 <P>  <P>
 The only time that a line break in a pattern is specially recognized when  The only time that a line break in a pattern is specially recognized when
compiling is when PCRE_EXTENDED is set. CR and LF are whitespace characters,compiling is when PCRE_EXTENDED is set. CR and LF are white space characters,
 and so are ignored in this mode. Also, an unescaped # outside a character class  and so are ignored in this mode. Also, an unescaped # outside a character class
 indicates a comment that lasts until after the next line break sequence. In  indicates a comment that lasts until after the next line break sequence. In
 other circumstances, line break sequences in patterns are treated as literal  other circumstances, line break sequences in patterns are treated as literal
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 isof 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 useonly 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 theprovokes an error. Details of how this option changes the behaviour of PCRE are
behaviour of PCRE are given in thegiven 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 isWhen PCRE_UTF8 is set, the validity of the pattern as a UTF-8
automatically checked. There is a discussion about thestring 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 mainin 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 wanterror. 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_CHECKthis 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 aWhen 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 optionundefined. 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 suppressbe 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 fallenboth 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 (&#62;= 0xd800 && &#60;= 0xdfff)
     74  invalid UTF-16 string (specifically UTF-16)
     75  name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN)
     76  character value in \u.... sequence is too large
 </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 895  wants to pass any of the other fields to <b>pcre_exec( Line 951  wants to pass any of the other fields to <b>pcre_exec(
 <b>pcre_dfa_exec()</b>, it must set up its own <b>pcre_extra</b> block.  <b>pcre_dfa_exec()</b>, it must set up its own <b>pcre_extra</b> block.
 </P>  </P>
 <P>  <P>
The second argument of <b>pcre_study()</b> contains option bits. There is onlyThe second argument of <b>pcre_study()</b> contains option bits. There are three
one option: PCRE_STUDY_JIT_COMPILE. If this is set, and the just-in-timeoptions:
compiler is available, the pattern is further compiled into machine code that<pre>
executes much faster than the <b>pcre_exec()</b> matching function. If  PCRE_STUDY_JIT_COMPILE
the just-in-time compiler is not available, this option is ignored. All other  PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE
bits in the <i>options</i> argument must be zero.  PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE
 </pre>
 If any of these are set, and the just-in-time compiler is available, the
 pattern is further compiled into machine code that executes much faster than
 the <b>pcre_exec()</b> interpretive matching function. If the just-in-time
 compiler is not available, these options are ignored. All other bits in the
 <i>options</i> argument must be zero.
 </P>  </P>
 <P>  <P>
 JIT compilation is a heavyweight optimization. It can take some time for  JIT compilation is a heavyweight optimization. It can take some time for
Line 925  When you are finished with a pattern, you can free the Line 987  When you are finished with a pattern, you can free the
 study data by calling <b>pcre_free_study()</b>. This function was added to the  study data by calling <b>pcre_free_study()</b>. This function was added to the
 API for release 8.20. For earlier versions, the memory could be freed with  API for release 8.20. For earlier versions, the memory could be freed with
 <b>pcre_free()</b>, just like the pattern itself. This will still work in cases  <b>pcre_free()</b>, just like the pattern itself. This will still work in cases
where PCRE_STUDY_JIT_COMPILE is not used, but it is advisable to change to thewhere JIT optimization is not used, but it is advisable to change to the new
new function when convenient.function when convenient.
 </P>  </P>
 <P>  <P>
 This is a typical way in which <b>pcre_study</b>() is used (except that in a  This is a typical way in which <b>pcre_study</b>() is used (except that in a
Line 958  in a calling program via the <b>pcre_fullinfo()</b> fu Line 1020  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
<b>pcre_dfa_exec()</b>. However, they are not used by <b>pcre_exec()</b> if<b>pcre_dfa_exec()</b>, and the information is also used by the JIT compiler.
<b>pcre_study()</b> is called with the PCRE_STUDY_JIT_COMPILE option, andThe optimizations can be disabled by setting the PCRE_NO_START_OPTIMIZE option
just-in-time compiling is successful. The optimizations can be disabled bywhen calling <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>, but if this is done,
setting the PCRE_NO_START_OPTIMIZE option when calling <b>pcre_exec()</b> orJIT execution is also disabled. You might want to do this if your pattern
<b>pcre_dfa_exec()</b>. You might want to do this if your pattern containscontains callouts or (*MARK) and you want to make use of these facilities in
callouts or (*MARK) (which cannot be handled by the JIT compiler), and you wantcases where matching fails. See the discussion of PCRE_NO_START_OPTIMIZE
to make use of these facilities in cases where matching fails. See the 
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 codesvalue. When running in UTF-8 mode, this applies only to characters
less than 128. By default, higher-valued codes never match escapes such as \wwith 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 charactersuch 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 compileUnicode character property support. Alternatively, the PCRE_UCP option can be
time; this causes \w and friends to use Unicode property support instead ofset 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 aresupport instead of built-in tables. The use of locales with Unicode is
handling characters with codes greater than 128, you should either use UTF-8discouraged. 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 1094  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 ispattern. 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 1112  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 ofcheck 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 1157  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 aReturn 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 iswhere 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 asIf there is a fixed first value, for example, the letter "c" from a pattern
(cat|cow|coyote), its value is returned. Otherwise, if eithersuch 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 1187  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 matchingtable 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 1135  Return 1 if the (?J) or (?-J) option setting is used i Line 1205  Return 1 if the (?J) or (?-J) option setting is used i
 <pre>  <pre>
   PCRE_INFO_JIT    PCRE_INFO_JIT
 </pre>  </pre>
Return 1 if the pattern was studied with the PCRE_STUDY_JIT_COMPILE option, andReturn 1 if the pattern was studied with one of the JIT options, and
 just-in-time compiling was successful. The fourth argument should point to an  just-in-time compiling was successful. The fourth argument should point to an
 <b>int</b> variable. A return value of 0 means that JIT support is not available  <b>int</b> variable. A return value of 0 means that JIT support is not available
in this version of PCRE, or that the pattern was not studied with thein this version of PCRE, or that the pattern was not studied with a JIT option,
PCRE_STUDY_JIT_COMPILE option, or that the JIT compiler could not handle thisor that the JIT compiler could not handle this particular pattern. See the
particular pattern. See the 
 <a href="pcrejit.html"><b>pcrejit</b></a>  <a href="pcrejit.html"><b>pcrejit</b></a>
 documentation for details of what can and cannot be handled.  documentation for details of what can and cannot be handled.
 <pre>  <pre>
   PCRE_INFO_JITSIZE    PCRE_INFO_JITSIZE
 </pre>  </pre>
If the pattern was successfully studied with the PCRE_STUDY_JIT_COMPILE option,If the pattern was successfully studied with a JIT option, return the size of
return the size of the JIT compiled code, otherwise return zero. The fourththe JIT compiled code, otherwise return zero. The fourth argument should point
argument should point to a <b>size_t</b> variable.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 matchedReturn 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 fourthmatched 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 isfourth 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 itvalue, -1 is returned. For anchored patterns, a last literal value is recorded
follows something of variable length. For example, for the patternonly 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>
     PCRE_INFO_MAXLOOKBEHIND
   </pre>
   Return the number of characters (NB not bytes) in the longest lookbehind
   assertion in the pattern. Note that the simple assertions \b and \B require a
   one-character lookbehind. This information is useful when doing multi-segment
   matching using the partial matching facilities.
   <pre>
   PCRE_INFO_MINLENGTH    PCRE_INFO_MINLENGTH
 </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-8value 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. Anumber 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 1265  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 entryentry 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. Thethe 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 1285  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 - isafter compilation by the 8-bit library (assume PCRE_EXTENDED is set, so white
ignored):space - including newlines - is ignored):
 <pre>  <pre>
   (?&#60;date&#62; (?&#60;year&#62;(\d\d)?\d\d) - (?&#60;month&#62;\d\d) - (?&#60;day&#62;\d\d) )    (?&#60;date&#62; (?&#60;year&#62;(\d\d)?\d\d) - (?&#60;month&#62;\d\d) - (?&#60;day&#62;\d\d) )
 </pre>  </pre>
Line 1258  For such patterns, the PCRE_ANCHORED bit is set in the Line 1336  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 aReturn 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 asinclude 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 orplace 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 aReturn 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 entitledto 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 1382  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 1447  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>
The <i>flags</i> field is a bitmap that specifies which of the other fieldsIn the 16-bit version of this structure, the <i>mark</i> field has type
are set. The flag bits are:"PCRE_UCHAR16 **".
 </P>
 <P>
 The <i>flags</i> field is used to specify which of the other fields are set. The
 flag bits are:
 <pre>  <pre>
  PCRE_EXTRA_STUDY_DATA  PCRE_EXTRA_CALLOUT_DATA
   PCRE_EXTRA_EXECUTABLE_JIT    PCRE_EXTRA_EXECUTABLE_JIT
     PCRE_EXTRA_MARK
   PCRE_EXTRA_MATCH_LIMIT    PCRE_EXTRA_MATCH_LIMIT
   PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
  PCRE_EXTRA_CALLOUT_DATA  PCRE_EXTRA_STUDY_DATA
   PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
   PCRE_EXTRA_MARK  
 </pre>  </pre>
 Other flag bits should be set to zero. The <i>study_data</i> field and sometimes  Other flag bits should be set to zero. The <i>study_data</i> field and sometimes
 the <i>executable_jit</i> field are set in the <b>pcre_extra</b> block that is  the <i>executable_jit</i> field are set in the <b>pcre_extra</b> block that is
 returned by <b>pcre_study()</b>, together with the appropriate flag bits. You  returned by <b>pcre_study()</b>, together with the appropriate flag bits. You
should not set these yourself, but you may add to the block by setting theshould not set these yourself, but you may add to the block by setting other
other fields and their corresponding flag bits.fields and their corresponding flag bits.
 </P>  </P>
 <P>  <P>
 The <i>match_limit</i> field provides a means of preventing PCRE from using up a  The <i>match_limit</i> field provides a means of preventing PCRE from using up a
Line 1425  in the subject string. Line 1484  in the subject string.
 </P>  </P>
 <P>  <P>
 When <b>pcre_exec()</b> is called with a pattern that was successfully studied  When <b>pcre_exec()</b> is called with a pattern that was successfully studied
with the PCRE_STUDY_JIT_COMPILE option, the way that the matching is executedwith a JIT option, the way that the matching is executed is entirely different.
is entirely different. However, there is still the possibility of runawayHowever, there is still the possibility of runaway matching that goes on for a
matching that goes on for a very long time, and so the <i>match_limit</i> valuevery long time, and so the <i>match_limit</i> value is also used in this case
is also used in this case (but in a different way) to limit how long the(but in a different way) to limit how long the matching can continue.
matching can continue. 
 </P>  </P>
 <P>  <P>
 The default value for the limit can be set when PCRE is built; the default  The default value for the limit can be set when PCRE is built; the default
Line 1450  This limit is of use only if it is set smaller than <i Line 1508  This limit is of use only if it is set smaller than <i
 Limiting the recursion depth limits the amount of machine stack that can be  Limiting the recursion depth limits the amount of machine stack that can be
 used, or, when PCRE has been compiled to use memory on the heap instead of the  used, or, when PCRE has been compiled to use memory on the heap instead of the
 stack, the amount of heap memory that can be used. This limit is not relevant,  stack, the amount of heap memory that can be used. This limit is not relevant,
and is ignored, if the pattern was successfully studied withand is ignored, when matching is done using JIT compiled code.
PCRE_STUDY_JIT_COMPILE. 
 </P>  </P>
 <P>  <P>
 The default value for <i>match_limit_recursion</i> can be set when PCRE is  The default value for <i>match_limit_recursion</i> can be set when PCRE is
Line 1482  documentation for a discussion of saving compiled patt Line 1539  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 anybe 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 thevariable 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 1502  Option bits for <b>pcre_exec()</b> Line 1559  Option bits for <b>pcre_exec()</b>
 The unused bits of the <i>options</i> argument for <b>pcre_exec()</b> must be  The unused bits of the <i>options</i> argument for <b>pcre_exec()</b> must be
 zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_<i>xxx</i>,  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_<i>xxx</i>,
 PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, andPCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, and
PCRE_PARTIAL_HARD.PCRE_PARTIAL_SOFT.
 </P>  </P>
 <P>  <P>
If the pattern was successfully studied with the PCRE_STUDY_JIT_COMPILE option,If the pattern was successfully studied with one of the just-in-time (JIT)
the only supported options for JIT execution are PCRE_NO_UTF8_CHECK,compile options, the only supported options for JIT execution are
PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NOTEMPTY_ATSTART. Note inPCRE_NO_UTF8_CHECK, PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY,
particular that partial matching is not supported. If an unsupported option isPCRE_NOTEMPTY_ATSTART, PCRE_PARTIAL_HARD, and PCRE_PARTIAL_SOFT. If an
used, JIT execution is disabled and the normal interpretive code inunsupported option is used, JIT execution is disabled and the normal
<b>pcre_exec()</b> is run.interpretive code in <b>pcre_exec()</b> is run.
 <pre>  <pre>
   PCRE_ANCHORED    PCRE_ANCHORED
 </pre>  </pre>
Line 1634  causing performance to suffer, but ensuring that in ca Line 1691  causing performance to suffer, but ensuring that in ca
 "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)  "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
 are considered at every possible starting position in the subject string. If  are considered at every possible starting position in the subject string. If
 PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching  PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching
time.time. The use of PCRE_NO_START_OPTIMIZE disables JIT execution; when it is set,
 matching is always done using interpretively.
 </P>  </P>
 <P>  <P>
 Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.  Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
Line 1668  returned. Line 1726  returned.
 </pre>  </pre>
 When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8
 string is automatically checked when <b>pcre_exec()</b> is subsequently called.  string is automatically checked when <b>pcre_exec()</b> is subsequently called.
The value of <i>startoffset</i> is also checked to ensure that it points to theThe entire string is checked before any other processing takes place. The value
start of a UTF-8 character. There is a discussion about the validity of UTF-8of <i>startoffset</i> is also checked to ensure that it points to the start of a
strings in theUTF-8 character. There is a discussion about the
<a href="pcre.html#utf8strings">section on UTF-8 support</a><a href="pcreunicode.html#utf8strings">validity of UTF-8 strings</a>
in the mainin 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_exec()</b> returnspage. If an invalid sequence of bytes is found, <b>pcre_exec()</b> returns the
the error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem iserror PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is a
a truncated UTF-8 character at the end of the subject, PCRE_ERROR_SHORTUTF8. Intruncated character at the end of the subject, PCRE_ERROR_SHORTUTF8. In both
both cases, information about the precise nature of the error may also becases, information about the precise nature of the error may also be returned
returned (see the descriptions of these errors in the section entitled \fIError(see the descriptions of these errors in the section entitled \fIError return
return values from\fP <b>pcre_exec()</b>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 1749  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 thethe 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 anof 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> isinvalid 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 1786  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 1823  string that it matched that is returned. Line 1881  string that it matched that is returned.
 <P>  <P>
 If the vector is too small to hold all the captured substring offsets, it is  If the vector is too small to hold all the captured substring offsets, it is
 used as far as possible (up to two-thirds of its length), and the function  used as far as possible (up to two-thirds of its length), and the function
returns a value of zero. If neither the actual string matched not any capturedreturns a value of zero. If neither the actual string matched nor any captured
 substrings are of interest, <b>pcre_exec()</b> may be called with <i>ovector</i>  substrings are of interest, <b>pcre_exec()</b> may be called with <i>ovector</i>
 passed as NULL and <i>ovecsize</i> as zero. However, if the pattern contains  passed as NULL and <i>ovecsize</i> as zero. However, if the pattern contains
 back references and the <i>ovector</i> is not big enough to remember the related  back references and the <i>ovector</i> is not big enough to remember the related
Line 2022  time. Line 2080  time.
 <pre>  <pre>
   PCRE_ERROR_JIT_STACKLIMIT (-27)    PCRE_ERROR_JIT_STACKLIMIT (-27)
 </pre>  </pre>
This error is returned when a pattern that was successfully studied using theThis error is returned when a pattern that was successfully studied using a
PCRE_STUDY_JIT_COMPILE option is being matched, but the memory available forJIT compile option is being matched, but the memory available for the
the just-in-time processing stack is not large enough. See thejust-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, -22, and -30 are not used by <b>pcre_exec()</b>.
 <a name="badutf8reasons"></a></P>  <a name="badutf8reasons"></a></P>
 <br><b>  <br><b>
 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 2180  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 2275  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 2339  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 2377  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 2395  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 2494  When a recursive subpattern is processed, the matching Line 2594  When a recursive subpattern is processed, the matching
 recursively, using private vectors for <i>ovector</i> and <i>workspace</i>. This  recursively, using private vectors for <i>ovector</i> and <i>workspace</i>. This
 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.
   <pre>
     PCRE_ERROR_DFA_BADRESTART (-30)
   </pre>
   When <b>pcre_dfa_exec()</b> is called with the <b>PCRE_DFA_RESTART</b> option,
   some plausibility checks are made on the contents of the workspace, which
   should contain data about the previous partial match. If any of these checks
   fail, this error is given.
 </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 2617  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 2011Last updated: 17 June 2012
 <br>  <br>
Copyright &copy; 1997-2011 University of Cambridge.Copyright &copy; 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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