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# Line 13  from the original man page. If there is Line 13  from the original man page. If there is
13  man page, in case the conversion went wrong.  man page, in case the conversion went wrong.
14  <br>  <br>
15  <ul>  <ul>
16  <li><a name="TOC1" href="#SEC1">PCRE NATIVE API</a>  <li><a name="TOC1" href="#SEC1">PCRE NATIVE API BASIC FUNCTIONS</a>
17  <li><a name="TOC2" href="#SEC2">PCRE API OVERVIEW</a>  <li><a name="TOC2" href="#SEC2">PCRE NATIVE API AUXILIARY FUNCTIONS</a>
18  <li><a name="TOC3" href="#SEC3">NEWLINES</a>  <li><a name="TOC3" href="#SEC3">PCRE NATIVE API INDIRECTED FUNCTIONS</a>
19  <li><a name="TOC4" href="#SEC4">MULTITHREADING</a>  <li><a name="TOC4" href="#SEC4">PCRE API OVERVIEW</a>
20  <li><a name="TOC5" href="#SEC5">SAVING PRECOMPILED PATTERNS FOR LATER USE</a>  <li><a name="TOC5" href="#SEC5">NEWLINES</a>
21  <li><a name="TOC6" href="#SEC6">CHECKING BUILD-TIME OPTIONS</a>  <li><a name="TOC6" href="#SEC6">MULTITHREADING</a>
22  <li><a name="TOC7" href="#SEC7">COMPILING A PATTERN</a>  <li><a name="TOC7" href="#SEC7">SAVING PRECOMPILED PATTERNS FOR LATER USE</a>
23  <li><a name="TOC8" href="#SEC8">COMPILATION ERROR CODES</a>  <li><a name="TOC8" href="#SEC8">CHECKING BUILD-TIME OPTIONS</a>
24  <li><a name="TOC9" href="#SEC9">STUDYING A PATTERN</a>  <li><a name="TOC9" href="#SEC9">COMPILING A PATTERN</a>
25  <li><a name="TOC10" href="#SEC10">LOCALE SUPPORT</a>  <li><a name="TOC10" href="#SEC10">COMPILATION ERROR CODES</a>
26  <li><a name="TOC11" href="#SEC11">INFORMATION ABOUT A PATTERN</a>  <li><a name="TOC11" href="#SEC11">STUDYING A PATTERN</a>
27  <li><a name="TOC12" href="#SEC12">OBSOLETE INFO FUNCTION</a>  <li><a name="TOC12" href="#SEC12">LOCALE SUPPORT</a>
28  <li><a name="TOC13" href="#SEC13">REFERENCE COUNTS</a>  <li><a name="TOC13" href="#SEC13">INFORMATION ABOUT A PATTERN</a>
29  <li><a name="TOC14" href="#SEC14">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</a>  <li><a name="TOC14" href="#SEC14">OBSOLETE INFO FUNCTION</a>
30  <li><a name="TOC15" href="#SEC15">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a>  <li><a name="TOC15" href="#SEC15">REFERENCE COUNTS</a>
31  <li><a name="TOC16" href="#SEC16">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a>  <li><a name="TOC16" href="#SEC16">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</a>
32  <li><a name="TOC17" href="#SEC17">DUPLICATE SUBPATTERN NAMES</a>  <li><a name="TOC17" href="#SEC17">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a>
33  <li><a name="TOC18" href="#SEC18">FINDING ALL POSSIBLE MATCHES</a>  <li><a name="TOC18" href="#SEC18">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a>
34  <li><a name="TOC19" href="#SEC19">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a>  <li><a name="TOC19" href="#SEC19">DUPLICATE SUBPATTERN NAMES</a>
35  <li><a name="TOC20" href="#SEC20">SEE ALSO</a>  <li><a name="TOC20" href="#SEC20">FINDING ALL POSSIBLE MATCHES</a>
36  <li><a name="TOC21" href="#SEC21">AUTHOR</a>  <li><a name="TOC21" href="#SEC21">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a>
37  <li><a name="TOC22" href="#SEC22">REVISION</a>  <li><a name="TOC22" href="#SEC22">SEE ALSO</a>
38    <li><a name="TOC23" href="#SEC23">AUTHOR</a>
39    <li><a name="TOC24" href="#SEC24">REVISION</a>
40  </ul>  </ul>
41  <br><a name="SEC1" href="#TOC1">PCRE NATIVE API</a><br>  <br><a name="SEC1" href="#TOC1">PCRE NATIVE API BASIC FUNCTIONS</a><br>
42  <P>  <P>
43  <b>#include &#60;pcre.h&#62;</b>  <b>#include &#60;pcre.h&#62;</b>
44  </P>  </P>
# Line 56  man page, in case the conversion went wr Line 58  man page, in case the conversion went wr
58  <b>const char **<i>errptr</i>);</b>  <b>const char **<i>errptr</i>);</b>
59  </P>  </P>
60  <P>  <P>
61    <b>void pcre_free_study(pcre_extra *<i>extra</i>);</b>
62    </P>
63    <P>
64  <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>
65  <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>
66  <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>
67  </P>  </P>
68    <br><a name="SEC2" href="#TOC1">PCRE NATIVE API AUXILIARY FUNCTIONS</a><br>
69    <P>
70    <b>pcre_jit_stack *pcre_jit_stack_alloc(int <i>startsize</i>, int <i>maxsize</i>);</b>
71    </P>
72    <P>
73    <b>void pcre_jit_stack_free(pcre_jit_stack *<i>stack</i>);</b>
74    </P>
75    <P>
76    <b>void pcre_assign_jit_stack(pcre_extra *<i>extra</i>,</b>
77    <b>pcre_jit_callback <i>callback</i>, void *<i>data</i>);</b>
78    </P>
79  <P>  <P>
80  <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>
81  <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 126  man page, in case the conversion went wr Line 142  man page, in case the conversion went wr
142  <P>  <P>
143  <b>char *pcre_version(void);</b>  <b>char *pcre_version(void);</b>
144  </P>  </P>
145    <br><a name="SEC3" href="#TOC1">PCRE NATIVE API INDIRECTED FUNCTIONS</a><br>
146  <P>  <P>
147  <b>void *(*pcre_malloc)(size_t);</b>  <b>void *(*pcre_malloc)(size_t);</b>
148  </P>  </P>
# Line 141  man page, in case the conversion went wr Line 158  man page, in case the conversion went wr
158  <P>  <P>
159  <b>int (*pcre_callout)(pcre_callout_block *);</b>  <b>int (*pcre_callout)(pcre_callout_block *);</b>
160  </P>  </P>
161  <br><a name="SEC2" href="#TOC1">PCRE API OVERVIEW</a><br>  <br><a name="SEC4" href="#TOC1">PCRE API OVERVIEW</a><br>
162  <P>  <P>
163  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
164  also some wrapper functions that correspond to the POSIX regular expression  also some wrapper functions that correspond to the POSIX regular expression
165  API. These are described in the  API, but they do not give access to all the functionality. They are described
166    in the
167  <a href="pcreposix.html"><b>pcreposix</b></a>  <a href="pcreposix.html"><b>pcreposix</b></a>
168  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++
169  wrapper is distributed with PCRE. It is documented in the  wrapper is also distributed with PCRE. It is documented in the
170  <a href="pcrecpp.html"><b>pcrecpp</b></a>  <a href="pcrecpp.html"><b>pcrecpp</b></a>
171  page.  page.
172  </P>  </P>
# Line 179  documentation, and the Line 197  documentation, and the
197  documentation describes how to compile and run it.  documentation describes how to compile and run it.
198  </P>  </P>
199  <P>  <P>
200    Just-in-time compiler support is an optional feature of PCRE that can be built
201    in appropriate hardware environments. It greatly speeds up the matching
202    performance of many patterns. Simple programs can easily request that it be
203    used if available, by setting an option that is ignored when it is not
204    relevant. More complicated programs might need to make use of the functions
205    <b>pcre_jit_stack_alloc()</b>, <b>pcre_jit_stack_free()</b>, and
206    <b>pcre_assign_jit_stack()</b> in order to control the JIT code's memory usage.
207    These functions are discussed in the
208    <a href="pcrejit.html"><b>pcrejit</b></a>
209    documentation.
210    </P>
211    <P>
212  A second matching function, <b>pcre_dfa_exec()</b>, which is not  A second matching function, <b>pcre_dfa_exec()</b>, which is not
213  Perl-compatible, is also provided. This uses a different algorithm for the  Perl-compatible, is also provided. This uses a different algorithm for the
214  matching. The alternative algorithm finds all possible matches (at a given  matching. The alternative algorithm finds all possible matches (at a given
# Line 254  points during a matching operation. Deta Line 284  points during a matching operation. Deta
284  <a href="pcrecallout.html"><b>pcrecallout</b></a>  <a href="pcrecallout.html"><b>pcrecallout</b></a>
285  documentation.  documentation.
286  <a name="newlines"></a></P>  <a name="newlines"></a></P>
287  <br><a name="SEC3" href="#TOC1">NEWLINES</a><br>  <br><a name="SEC5" href="#TOC1">NEWLINES</a><br>
288  <P>  <P>
289  PCRE supports five different conventions for indicating line breaks in  PCRE supports five different conventions for indicating line breaks in
290  strings: a single CR (carriage return) character, a single LF (linefeed)  strings: a single CR (carriage return) character, a single LF (linefeed)
# Line 293  The choice of newline convention does no Line 323  The choice of newline convention does no
323  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
324  controlled in a similar way, but by separate options.  controlled in a similar way, but by separate options.
325  </P>  </P>
326  <br><a name="SEC4" href="#TOC1">MULTITHREADING</a><br>  <br><a name="SEC6" href="#TOC1">MULTITHREADING</a><br>
327  <P>  <P>
328  The PCRE functions can be used in multi-threading applications, with the  The PCRE functions can be used in multi-threading applications, with the
329  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 304  callout function pointed to by pcre_c Line 334  callout function pointed to by pcre_c
334  The compiled form of a regular expression is not altered during matching, so  The compiled form of a regular expression is not altered during matching, so
335  the same compiled pattern can safely be used by several threads at once.  the same compiled pattern can safely be used by several threads at once.
336  </P>  </P>
337  <br><a name="SEC5" href="#TOC1">SAVING PRECOMPILED PATTERNS FOR LATER USE</a><br>  <P>
338    If the just-in-time optimization feature is being used, it needs separate
339    memory stack areas for each thread. See the
340    <a href="pcrejit.html"><b>pcrejit</b></a>
341    documentation for more details.
342    </P>
343    <br><a name="SEC7" href="#TOC1">SAVING PRECOMPILED PATTERNS FOR LATER USE</a><br>
344  <P>  <P>
345  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
346  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
# Line 314  documentation. However, compiling a regu Line 350  documentation. However, compiling a regu
350  for use with a different version is not guaranteed to work and may cause  for use with a different version is not guaranteed to work and may cause
351  crashes.  crashes.
352  </P>  </P>
353  <br><a name="SEC6" href="#TOC1">CHECKING BUILD-TIME OPTIONS</a><br>  <br><a name="SEC8" href="#TOC1">CHECKING BUILD-TIME OPTIONS</a><br>
354  <P>  <P>
355  <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>
356  </P>  </P>
# Line 339  otherwise it is set to zero. Line 375  otherwise it is set to zero.
375  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
376  properties is available; otherwise it is set to zero.  properties is available; otherwise it is set to zero.
377  <pre>  <pre>
378      PCRE_CONFIG_JIT
379    </pre>
380    The output is an integer that is set to one if support for just-in-time
381    compiling is available; otherwise it is set to zero.
382    <pre>
383    PCRE_CONFIG_NEWLINE    PCRE_CONFIG_NEWLINE
384  </pre>  </pre>
385  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 393  of recursive function calls. In this cas Line 434  of recursive function calls. In this cas
434  <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
435  avoiding the use of the stack.  avoiding the use of the stack.
436  </P>  </P>
437  <br><a name="SEC7" href="#TOC1">COMPILING A PATTERN</a><br>  <br><a name="SEC9" href="#TOC1">COMPILING A PATTERN</a><br>
438  <P>  <P>
439  <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>
440  <b>const char **<i>errptr</i>, int *<i>erroffset</i>,</b>  <b>const char **<i>errptr</i>, int *<i>erroffset</i>,</b>
# Line 435  within the pattern (see the detailed des Line 476  within the pattern (see the detailed des
476  documentation). For those options that can be different in different parts of  documentation). For those options that can be different in different parts of
477  the pattern, the contents of the <i>options</i> argument specifies their  the pattern, the contents of the <i>options</i> argument specifies their
478  settings at the start of compilation and execution. The PCRE_ANCHORED,  settings at the start of compilation and execution. The PCRE_ANCHORED,
479  PCRE_BSR_<i>xxx</i>, and PCRE_NEWLINE_<i>xxx</i> options can be set at the time  PCRE_BSR_<i>xxx</i>, PCRE_NEWLINE_<i>xxx</i>, PCRE_NO_UTF8_CHECK, and
480  of matching as well as at compile time.  PCRE_NO_START_OPT options can be set at the time of matching as well as at
481    compile time.
482  </P>  </P>
483  <P>  <P>
484  If <i>errptr</i> is NULL, <b>pcre_compile()</b> returns NULL immediately.  If <i>errptr</i> is NULL, <b>pcre_compile()</b> returns NULL immediately.
485  Otherwise, if compilation of a pattern fails, <b>pcre_compile()</b> returns  Otherwise, if compilation of a pattern fails, <b>pcre_compile()</b> returns
486  NULL, and sets the variable pointed to by <i>errptr</i> to point to a textual  NULL, and sets the variable pointed to by <i>errptr</i> to point to a textual
487  error message. This is a static string that is part of the library. You must  error message. This is a static string that is part of the library. You must
488  not try to free it. The byte offset from the start of the pattern to the  not try to free it. Normally, the offset from the start of the pattern to the
489  character that was being processed when the error was discovered is placed in  byte that was being processed when the error was discovered is placed in the
490  the variable pointed to by <i>erroffset</i>, which must not be NULL. If it is,  variable pointed to by <i>erroffset</i>, which must not be NULL (if it is, an
491  an immediate error is given. Some errors are not detected until checks are  immediate error is given). However, for an invalid UTF-8 string, the offset is
492  carried out when the whole pattern has been scanned; in this case the offset is  that of the first byte of the failing character. Also, some errors are not
493  set to the end of the pattern.  detected until checks are carried out when the whole pattern has been scanned;
494    in these cases the offset passed back is the length of the pattern.
495    </P>
496    <P>
497    Note that the offset is in bytes, not characters, even in UTF-8 mode. It may
498    sometimes point into the middle of a UTF-8 character.
499  </P>  </P>
500  <P>  <P>
501  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 528  pattern. Line 575  pattern.
575  <pre>  <pre>
576    PCRE_DOTALL    PCRE_DOTALL
577  </pre>  </pre>
578  If this bit is set, a dot metacharater in the pattern matches all characters,  If this bit is set, a dot metacharacter in the pattern matches a character of
579  including those that indicate newline. Without it, a dot does not match when  any value, including one that indicates a newline. However, it only ever
580  the current position is at a newline. This option is equivalent to Perl's /s  matches one character, even if newlines are coded as CRLF. Without this option,
581  option, and it can be changed within a pattern by a (?s) option setting. A  a dot does not match when the current position is at a newline. This option is
582  negative class such as [^a] always matches newline characters, independent of  equivalent to Perl's /s option, and it can be changed within a pattern by a
583  the setting of this option.  (?s) option setting. A negative class such as [^a] always matches newline
584    characters, independent of the setting of this option.
585  <pre>  <pre>
586    PCRE_DUPNAMES    PCRE_DUPNAMES
587  </pre>  </pre>
# Line 554  ignored. This is equivalent to Perl's /x Line 602  ignored. This is equivalent to Perl's /x
602  pattern by a (?x) option setting.  pattern by a (?x) option setting.
603  </P>  </P>
604  <P>  <P>
605    Which characters are interpreted as newlines is controlled by the options
606    passed to <b>pcre_compile()</b> or by a special sequence at the start of the
607    pattern, as described in the section entitled
608    <a href="pcrepattern.html#newlines">"Newline conventions"</a>
609    in the <b>pcrepattern</b> documentation. Note that the end of this type of
610    comment is a literal newline sequence in the pattern; escape sequences that
611    happen to represent a newline do not count.
612    </P>
613    <P>
614  This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
615  Note, however, that this applies only to data characters. Whitespace characters  Note, however, that this applies only to data characters. Whitespace characters
616  may never appear within special character sequences in a pattern, for example  may never appear within special character sequences in a pattern, for example
617  within the sequence (?( which introduces a conditional subpattern.  within the sequence (?( that introduces a conditional subpattern.
618  <pre>  <pre>
619    PCRE_EXTRA    PCRE_EXTRA
620  </pre>  </pre>
# Line 592  character). Thus, the pattern AB]CD beco Line 649  character). Thus, the pattern AB]CD beco
649  string (by default this causes the current matching alternative to fail). A  string (by default this causes the current matching alternative to fail). A
650  pattern such as (\1)(a) succeeds when this option is set (assuming it can find  pattern such as (\1)(a) succeeds when this option is set (assuming it can find
651  an "a" in the subject), whereas it fails by default, for Perl compatibility.  an "a" in the subject), whereas it fails by default, for Perl compatibility.
652    </P>
653    <P>
654    (3) \U matches an upper case "U" character; by default \U causes a compile
655    time error (Perl uses \U to upper case subsequent characters).
656    </P>
657    <P>
658    (4) \u matches a lower case "u" character unless it is followed by four
659    hexadecimal digits, in which case the hexadecimal number defines the code point
660    to match. By default, \u causes a compile time error (Perl uses it to upper
661    case the following character).
662    </P>
663    <P>
664    (5) \x matches a lower case "x" character unless it is followed by two
665    hexadecimal digits, in which case the hexadecimal number defines the code point
666    to match. By default, as in Perl, a hexadecimal number is always expected after
667    \x, but it may have zero, one, or two digits (so, for example, \xz matches a
668    binary zero character followed by z).
669  <pre>  <pre>
670    PCRE_MULTILINE    PCRE_MULTILINE
671  </pre>  </pre>
# Line 637  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is Line 711  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is
711  other combinations may yield unused numbers and cause an error.  other combinations may yield unused numbers and cause an error.
712  </P>  </P>
713  <P>  <P>
714  The only time that a line break is specially recognized when compiling a  The only time that a line break in a pattern is specially recognized when
715  pattern is if PCRE_EXTENDED is set, and an unescaped # outside a character  compiling is when PCRE_EXTENDED is set. CR and LF are whitespace characters,
716  class is encountered. This indicates a comment that lasts until after the next  and so are ignored in this mode. Also, an unescaped # outside a character class
717  line break sequence. In other circumstances, line break sequences are treated  indicates a comment that lasts until after the next line break sequence. In
718  as literal data, except that in PCRE_EXTENDED mode, both CR and LF are treated  other circumstances, line break sequences in patterns are treated as literal
719  as whitespace characters and are therefore ignored.  data.
720  </P>  </P>
721  <P>  <P>
722  The newline option that is set at compile time becomes the default that is used  The newline option that is set at compile time becomes the default that is used
# Line 656  were followed by ?: but named parenthese Line 730  were followed by ?: but named parenthese
730  they acquire numbers in the usual way). There is no equivalent of this option  they acquire numbers in the usual way). There is no equivalent of this option
731  in Perl.  in Perl.
732  <pre>  <pre>
733      NO_START_OPTIMIZE
734    </pre>
735    This is an option that acts at matching time; that is, it is really an option
736    for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>. If it is set at compile time,
737    it is remembered with the compiled pattern and assumed at matching time. For
738    details see the discussion of PCRE_NO_START_OPTIMIZE
739    <a href="#execoptions">below.</a>
740    <pre>
741    PCRE_UCP    PCRE_UCP
742  </pre>  </pre>
743  This option changes the way PCRE processes \b, \d, \s, \w, and some of the  This option changes the way PCRE processes \B, \b, \D, \d, \S, \s, \W,
744  POSIX character classes. By default, only ASCII characters are recognized, but  \w, and some of the POSIX character classes. By default, only ASCII characters
745  if PCRE_UCP is set, Unicode properties are used instead to classify characters.  are recognized, but if PCRE_UCP is set, Unicode properties are used instead to
746  More details are given in the section on  classify characters. More details are given in the section on
747  <a href="pcre.html#genericchartypes">generic character types</a>  <a href="pcre.html#genericchartypes">generic character types</a>
748  in the  in the
749  <a href="pcrepattern.html"><b>pcrepattern</b></a>  <a href="pcrepattern.html"><b>pcrepattern</b></a>
# Line 682  of UTF-8 characters instead of single-by Line 764  of UTF-8 characters instead of single-by
764  available only when PCRE is built to include UTF-8 support. If not, the use  available only when PCRE is built to include UTF-8 support. If not, the use
765  of this option provokes an error. Details of how this option changes the  of this option provokes an error. Details of how this option changes the
766  behaviour of PCRE are given in the  behaviour of PCRE are given in the
767  <a href="pcre.html#utf8support">section on UTF-8 support</a>  <a href="pcreunicode.html"><b>pcreunicode</b></a>
 in the main  
 <a href="pcre.html"><b>pcre</b></a>  
768  page.  page.
769  <pre>  <pre>
770    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
# Line 702  pattern is undefined. It may cause your Line 782  pattern is undefined. It may cause your
782  can also be passed to <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>, to suppress  can also be passed to <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>, to suppress
783  the UTF-8 validity checking of subject strings.  the UTF-8 validity checking of subject strings.
784  </P>  </P>
785  <br><a name="SEC8" href="#TOC1">COMPILATION ERROR CODES</a><br>  <br><a name="SEC10" href="#TOC1">COMPILATION ERROR CODES</a><br>
786  <P>  <P>
787  The following table lists the error codes than may be returned by  The following table lists the error codes than may be returned by
788  <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
# Line 746  out of use. To avoid confusion, they hav Line 826  out of use. To avoid confusion, they hav
826    34  character value in \x{...} sequence is too large    34  character value in \x{...} sequence is too large
827    35  invalid condition (?(0)    35  invalid condition (?(0)
828    36  \C not allowed in lookbehind assertion    36  \C not allowed in lookbehind assertion
829    37  PCRE does not support \L, \l, \N, \U, or \u    37  PCRE does not support \L, \l, \N{name}, \U, or \u
830    38  number after (?C is &#62; 255    38  number after (?C is &#62; 255
831    39  closing ) for (?C expected    39  closing ) for (?C expected
832    40  recursive call could loop indefinitely    40  recursive call could loop indefinitely
# Line 762  out of use. To avoid confusion, they hav Line 842  out of use. To avoid confusion, they hav
842    50  [this code is not in use]    50  [this code is not in use]
843    51  octal value is greater than \377 (not in UTF-8 mode)    51  octal value is greater than \377 (not in UTF-8 mode)
844    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
845    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern
846            not found
847    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
848    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
849    56  inconsistent NEWLINE options    56  inconsistent NEWLINE options
# Line 775  out of use. To avoid confusion, they hav Line 856  out of use. To avoid confusion, they hav
856    62  subpattern name expected    62  subpattern name expected
857    63  digit expected after (?+    63  digit expected after (?+
858    64  ] is an invalid data character in JavaScript compatibility mode    64  ] is an invalid data character in JavaScript compatibility mode
859    65  different names for subpatterns of the same number are not allowed    65  different names for subpatterns of the same number are
860            not allowed
861    66  (*MARK) must have an argument    66  (*MARK) must have an argument
862    67  this version of PCRE is not compiled with PCRE_UCP support    67  this version of PCRE is not compiled with PCRE_UCP support
863      68  \c must be followed by an ASCII character
864      69  \k is not followed by a braced, angle-bracketed, or quoted name
865  </pre>  </pre>
866  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
867  be used if the limits were changed when PCRE was built.  be used if the limits were changed when PCRE was built.
868  </P>  <a name="studyingapattern"></a></P>
869  <br><a name="SEC9" href="#TOC1">STUDYING A PATTERN</a><br>  <br><a name="SEC11" href="#TOC1">STUDYING A PATTERN</a><br>
870  <P>  <P>
871  <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>
872  <b>const char **<i>errptr</i>);</b>  <b>const char **<i>errptr</i>);</b>
# Line 811  wants to pass any of the other fields to Line 895  wants to pass any of the other fields to
895  <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.
896  </P>  </P>
897  <P>  <P>
898  The second argument of <b>pcre_study()</b> contains option bits. At present, no  The second argument of <b>pcre_study()</b> contains option bits. There is only
899  options are defined, and this argument should always be zero.  one option: PCRE_STUDY_JIT_COMPILE. If this is set, and the just-in-time
900    compiler is available, the pattern is further compiled into machine code that
901    executes much faster than the <b>pcre_exec()</b> matching function. If
902    the just-in-time compiler is not available, this option is ignored. All other
903    bits in the <i>options</i> argument must be zero.
904    </P>
905    <P>
906    JIT compilation is a heavyweight optimization. It can take some time for
907    patterns to be analyzed, and for one-off matches and simple patterns the
908    benefit of faster execution might be offset by a much slower study time.
909    Not all patterns can be optimized by the JIT compiler. For those that cannot be
910    handled, matching automatically falls back to the <b>pcre_exec()</b>
911    interpreter. For more details, see the
912    <a href="pcrejit.html"><b>pcrejit</b></a>
913    documentation.
914  </P>  </P>
915  <P>  <P>
916  The third argument for <b>pcre_study()</b> is a pointer for an error message. If  The third argument for <b>pcre_study()</b> is a pointer for an error message. If
# Line 823  should test the error pointer for NULL a Line 921  should test the error pointer for NULL a
921  sure that it has run successfully.  sure that it has run successfully.
922  </P>  </P>
923  <P>  <P>
924  This is a typical call to <b>pcre_study</b>():  When you are finished with a pattern, you can free the memory used for the
925    study data by calling <b>pcre_free_study()</b>. This function was added to the
926    API for release 8.20. For earlier versions, the memory could be freed with
927    <b>pcre_free()</b>, just like the pattern itself. This will still work in cases
928    where PCRE_STUDY_JIT_COMPILE is not used, but it is advisable to change to the
929    new function when convenient.
930    </P>
931    <P>
932    This is a typical way in which <b>pcre_study</b>() is used (except that in a
933    real application there should be tests for errors):
934  <pre>  <pre>
935    pcre_extra *pe;    int rc;
936    pe = pcre_study(    pcre *re;
937      pcre_extra *sd;
938      re = pcre_compile("pattern", 0, &error, &erroroffset, NULL);
939      sd = pcre_study(
940      re,             /* result of pcre_compile() */      re,             /* result of pcre_compile() */
941      0,              /* no options exist */      0,              /* no options */
942      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
943      rc = pcre_exec(   /* see below for details of pcre_exec() options */
944        re, sd, "subject", 7, 0, 0, ovector, 30);
945      ...
946      pcre_free_study(sd);
947      pcre_free(re);
948  </pre>  </pre>
949  Studying a pattern does two things: first, a lower bound for the length of  Studying a pattern does two things: first, a lower bound for the length of
950  subject string that is needed to match the pattern is computed. This does not  subject string that is needed to match the pattern is computed. This does not
# Line 844  Studying a pattern is also useful for no Line 959  Studying a pattern is also useful for no
959  single fixed starting character. A bitmap of possible starting bytes is  single fixed starting character. A bitmap of possible starting bytes is
960  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
961  matching.  matching.
962    </P>
963    <P>
964    These two optimizations apply to both <b>pcre_exec()</b> and
965    <b>pcre_dfa_exec()</b>. However, they are not used by <b>pcre_exec()</b> if
966    <b>pcre_study()</b> is called with the PCRE_STUDY_JIT_COMPILE option, and
967    just-in-time compiling is successful. The optimizations can be disabled by
968    setting the PCRE_NO_START_OPTIMIZE option when calling <b>pcre_exec()</b> or
969    <b>pcre_dfa_exec()</b>. You might want to do this if your pattern contains
970    callouts or (*MARK) (which cannot be handled by the JIT compiler), and you want
971    to make use of these facilities in cases where matching fails. See the
972    discussion of PCRE_NO_START_OPTIMIZE
973    <a href="#execoptions">below.</a>
974  <a name="localesupport"></a></P>  <a name="localesupport"></a></P>
975  <br><a name="SEC10" href="#TOC1">LOCALE SUPPORT</a><br>  <br><a name="SEC12" href="#TOC1">LOCALE SUPPORT</a><br>
976  <P>  <P>
977  PCRE handles caseless matching, and determines whether characters are letters,  PCRE handles caseless matching, and determines whether characters are letters,
978  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
# Line 905  internal tables) to pcre_exec(). Line 1032  internal tables) to pcre_exec().
1032  this facility could be used to match a pattern in a different locale from the  this facility could be used to match a pattern in a different locale from the
1033  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
1034  below in the section on matching a pattern.  below in the section on matching a pattern.
1035  </P>  <a name="infoaboutpattern"></a></P>
1036  <br><a name="SEC11" href="#TOC1">INFORMATION ABOUT A PATTERN</a><br>  <br><a name="SEC13" href="#TOC1">INFORMATION ABOUT A PATTERN</a><br>
1037  <P>  <P>
1038  <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>
1039  <b>int <i>what</i>, void *<i>where</i>);</b>  <b>int <i>what</i>, void *<i>where</i>);</b>
# Line 937  check against passing an arbitrary memor Line 1064  check against passing an arbitrary memor
1064    size_t length;    size_t length;
1065    rc = pcre_fullinfo(    rc = pcre_fullinfo(
1066      re,               /* result of pcre_compile() */      re,               /* result of pcre_compile() */
1067      pe,               /* result of pcre_study(), or NULL */      sd,               /* result of pcre_study(), or NULL */
1068      PCRE_INFO_SIZE,   /* what is required */      PCRE_INFO_SIZE,   /* what is required */
1069      &length);         /* where to put the data */      &length);         /* where to put the data */
1070  </pre>  </pre>
# Line 1006  Return 1 if the (?J) or (?-J) option set Line 1133  Return 1 if the (?J) or (?-J) option set
1133  0. The fourth argument should point to an <b>int</b> variable. (?J) and  0. The fourth argument should point to an <b>int</b> variable. (?J) and
1134  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
1135  <pre>  <pre>
1136      PCRE_INFO_JIT
1137    </pre>
1138    Return 1 if the pattern was studied with the PCRE_STUDY_JIT_COMPILE option, and
1139    just-in-time compiling was successful. The fourth argument should point to an
1140    <b>int</b> variable. A return value of 0 means that JIT support is not available
1141    in this version of PCRE, or that the pattern was not studied with the
1142    PCRE_STUDY_JIT_COMPILE option, or that the JIT compiler could not handle this
1143    particular pattern. See the
1144    <a href="pcrejit.html"><b>pcrejit</b></a>
1145    documentation for details of what can and cannot be handled.
1146    <pre>
1147      PCRE_INFO_JITSIZE
1148    </pre>
1149    If the pattern was successfully studied with the PCRE_STUDY_JIT_COMPILE option,
1150    return the size of the JIT compiled code, otherwise return zero. The fourth
1151    argument should point to a <b>size_t</b> variable.
1152    <pre>
1153    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
1154  </pre>  </pre>
1155  Return the value of the rightmost literal byte that must exist in any matched  Return the value of the rightmost literal byte that must exist in any matched
# Line 1114  For such patterns, the PCRE_ANCHORED bit Line 1258  For such patterns, the PCRE_ANCHORED bit
1258  <pre>  <pre>
1259    PCRE_INFO_SIZE    PCRE_INFO_SIZE
1260  </pre>  </pre>
1261  Return the size of the compiled pattern, that is, the value that was passed as  Return the size of the compiled pattern. The fourth argument should point to a
1262  the argument to <b>pcre_malloc()</b> when PCRE was getting memory in which to  <b>size_t</b> variable. This value does not include the size of the <b>pcre</b>
1263  place the compiled data. The fourth argument should point to a <b>size_t</b>  structure that is returned by <b>pcre_compile()</b>. The value that is passed as
1264  variable.  the argument to <b>pcre_malloc()</b> when <b>pcre_compile()</b> is getting memory
1265    in which to place the compiled data is the value returned by this option plus
1266    the size of the <b>pcre</b> structure. Studying a compiled pattern, with or
1267    without JIT, does not alter the value returned by this option.
1268  <pre>  <pre>
1269    PCRE_INFO_STUDYSIZE    PCRE_INFO_STUDYSIZE
1270  </pre>  </pre>
1271  Return the size of the data block pointed to by the <i>study_data</i> field in  Return the size of the data block pointed to by the <i>study_data</i> field in a
1272  a <b>pcre_extra</b> block. That is, it is the value that was passed to  <b>pcre_extra</b> block. If <b>pcre_extra</b> is NULL, or there is no study data,
1273  <b>pcre_malloc()</b> when PCRE was getting memory into which to place the data  zero is returned. The fourth argument should point to a <b>size_t</b> variable.
1274  created by <b>pcre_study()</b>. If <b>pcre_extra</b> is NULL, or there is no  The <i>study_data</i> field is set by <b>pcre_study()</b> to record information
1275  study data, zero is returned. The fourth argument should point to a  that will speed up matching (see the section entitled
1276  <b>size_t</b> variable.  <a href="#studyingapattern">"Studying a pattern"</a>
1277    above). The format of the <i>study_data</i> block is private, but its length
1278    is made available via this option so that it can be saved and restored (see the
1279    <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
1280    documentation for details).
1281  </P>  </P>
1282  <br><a name="SEC12" href="#TOC1">OBSOLETE INFO FUNCTION</a><br>  <br><a name="SEC14" href="#TOC1">OBSOLETE INFO FUNCTION</a><br>
1283  <P>  <P>
1284  <b>int pcre_info(const pcre *<i>code</i>, int *<i>optptr</i>, int</b>  <b>int pcre_info(const pcre *<i>code</i>, int *<i>optptr</i>, int</b>
1285  <b>*<i>firstcharptr</i>);</b>  <b>*<i>firstcharptr</i>);</b>
# Line 1152  If the pattern is not anchored and the < Line 1303  If the pattern is not anchored and the <
1303  it is used to pass back information about the first character of any matched  it is used to pass back information about the first character of any matched
1304  string (see PCRE_INFO_FIRSTBYTE above).  string (see PCRE_INFO_FIRSTBYTE above).
1305  </P>  </P>
1306  <br><a name="SEC13" href="#TOC1">REFERENCE COUNTS</a><br>  <br><a name="SEC15" href="#TOC1">REFERENCE COUNTS</a><br>
1307  <P>  <P>
1308  <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>
1309  </P>  </P>
# Line 1176  Except when it is zero, the reference co Line 1327  Except when it is zero, the reference co
1327  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
1328  is different. (This seems a highly unlikely scenario.)  is different. (This seems a highly unlikely scenario.)
1329  </P>  </P>
1330  <br><a name="SEC14" href="#TOC1">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</a><br>  <br><a name="SEC16" href="#TOC1">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</a><br>
1331  <P>  <P>
1332  <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>
1333  <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 1186  is different. (This seems a highly unlik Line 1337  is different. (This seems a highly unlik
1337  The function <b>pcre_exec()</b> is called to match a subject string against a  The function <b>pcre_exec()</b> is called to match a subject string against a
1338  compiled pattern, which is passed in the <i>code</i> argument. If the  compiled pattern, which is passed in the <i>code</i> argument. If the
1339  pattern was studied, the result of the study should be passed in the  pattern was studied, the result of the study should be passed in the
1340  <i>extra</i> argument. This function is the main matching facility of the  <i>extra</i> argument. You can call <b>pcre_exec()</b> with the same <i>code</i>
1341  library, and it operates in a Perl-like manner. For specialist use there is  and <i>extra</i> arguments as many times as you like, in order to match
1342  also an alternative matching function, which is described  different subject strings with the same pattern.
1343    </P>
1344    <P>
1345    This function is the main matching facility of the library, and it operates in
1346    a Perl-like manner. For specialist use there is also an alternative matching
1347    function, which is described
1348  <a href="#dfamatch">below</a>  <a href="#dfamatch">below</a>
1349  in the section about the <b>pcre_dfa_exec()</b> function.  in the section about the <b>pcre_dfa_exec()</b> function.
1350  </P>  </P>
# Line 1229  fields (not necessarily in this order): Line 1385  fields (not necessarily in this order):
1385  <pre>  <pre>
1386    unsigned long int <i>flags</i>;    unsigned long int <i>flags</i>;
1387    void *<i>study_data</i>;    void *<i>study_data</i>;
1388      void *<i>executable_jit</i>;
1389    unsigned long int <i>match_limit</i>;    unsigned long int <i>match_limit</i>;
1390    unsigned long int <i>match_limit_recursion</i>;    unsigned long int <i>match_limit_recursion</i>;
1391    void *<i>callout_data</i>;    void *<i>callout_data</i>;
# Line 1239  The flags field is a bitmap that Line 1396  The flags field is a bitmap that
1396  are set. The flag bits are:  are set. The flag bits are:
1397  <pre>  <pre>
1398    PCRE_EXTRA_STUDY_DATA    PCRE_EXTRA_STUDY_DATA
1399      PCRE_EXTRA_EXECUTABLE_JIT
1400    PCRE_EXTRA_MATCH_LIMIT    PCRE_EXTRA_MATCH_LIMIT
1401    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1402    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1403    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1404    PCRE_EXTRA_MARK    PCRE_EXTRA_MARK
1405  </pre>  </pre>
1406  Other flag bits should be set to zero. The <i>study_data</i> field is set in the  Other flag bits should be set to zero. The <i>study_data</i> field and sometimes
1407  <b>pcre_extra</b> block that is returned by <b>pcre_study()</b>, together with  the <i>executable_jit</i> field are set in the <b>pcre_extra</b> block that is
1408  the appropriate flag bit. You should not set this yourself, but you may add to  returned by <b>pcre_study()</b>, together with the appropriate flag bits. You
1409  the block by setting the other fields and their corresponding flag bits.  should not set these yourself, but you may add to the block by setting the
1410    other fields and their corresponding flag bits.
1411  </P>  </P>
1412  <P>  <P>
1413  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 1257  but which have a very large number of po Line 1416  but which have a very large number of po
1416  classic example is a pattern that uses nested unlimited repeats.  classic example is a pattern that uses nested unlimited repeats.
1417  </P>  </P>
1418  <P>  <P>
1419  Internally, PCRE uses a function called <b>match()</b> which it calls repeatedly  Internally, <b>pcre_exec()</b> uses a function called <b>match()</b>, which it
1420  (sometimes recursively). The limit set by <i>match_limit</i> is imposed on the  calls repeatedly (sometimes recursively). The limit set by <i>match_limit</i> is
1421  number of times this function is called during a match, which has the effect of  imposed on the number of times this function is called during a match, which
1422  limiting the amount of backtracking that can take place. For patterns that are  has the effect of limiting the amount of backtracking that can take place. For
1423  not anchored, the count restarts from zero for each position in the subject  patterns that are not anchored, the count restarts from zero for each position
1424  string.  in the subject string.
1425    </P>
1426    <P>
1427    When <b>pcre_exec()</b> is called with a pattern that was successfully studied
1428    with the PCRE_STUDY_JIT_COMPILE option, the way that the matching is executed
1429    is entirely different. However, there is still the possibility of runaway
1430    matching that goes on for a very long time, and so the <i>match_limit</i> value
1431    is also used in this case (but in a different way) to limit how long the
1432    matching can continue.
1433  </P>  </P>
1434  <P>  <P>
1435  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 1280  total number of calls, because not all c Line 1447  total number of calls, because not all c
1447  This limit is of use only if it is set smaller than <i>match_limit</i>.  This limit is of use only if it is set smaller than <i>match_limit</i>.
1448  </P>  </P>
1449  <P>  <P>
1450  Limiting the recursion depth limits the amount of stack that can be used, or,  Limiting the recursion depth limits the amount of machine stack that can be
1451  when PCRE has been compiled to use memory on the heap instead of the stack, the  used, or, when PCRE has been compiled to use memory on the heap instead of the
1452  amount of heap memory that can be used.  stack, the amount of heap memory that can be used. This limit is not relevant,
1453    and is ignored, if the pattern was successfully studied with
1454    PCRE_STUDY_JIT_COMPILE.
1455  </P>  </P>
1456  <P>  <P>
1457  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 1335  zero. The only bits that may be set are Line 1504  zero. The only bits that may be set are
1504  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1505  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
1506  PCRE_PARTIAL_HARD.  PCRE_PARTIAL_HARD.
1507    </P>
1508    <P>
1509    If the pattern was successfully studied with the PCRE_STUDY_JIT_COMPILE option,
1510    the only supported options for JIT execution are PCRE_NO_UTF8_CHECK,
1511    PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NOTEMPTY_ATSTART. Note in
1512    particular that partial matching is not supported. If an unsupported option is
1513    used, JIT execution is disabled and the normal interpretive code in
1514    <b>pcre_exec()</b> is run.
1515  <pre>  <pre>
1516    PCRE_ANCHORED    PCRE_ANCHORED
1517  </pre>  </pre>
# Line 1433  if that fails, by advancing the starting Line 1610  if that fails, by advancing the starting
1610  ordinary match again. There is some code that demonstrates how to do this in  ordinary match again. There is some code that demonstrates how to do this in
1611  the  the
1612  <a href="pcredemo.html"><b>pcredemo</b></a>  <a href="pcredemo.html"><b>pcredemo</b></a>
1613  sample program.  sample program. In the most general case, you have to check to see if the
1614    newline convention recognizes CRLF as a newline, and if so, and the current
1615    character is CR followed by LF, advance the starting offset by two characters
1616    instead of one.
1617  <pre>  <pre>
1618    PCRE_NO_START_OPTIMIZE    PCRE_NO_START_OPTIMIZE
1619  </pre>  </pre>
# Line 1443  unanchored match must start with a speci Line 1623  unanchored match must start with a speci
1623  for that character, and fails immediately if it cannot find it, without  for that character, and fails immediately if it cannot find it, without
1624  actually running the main matching function. This means that a special item  actually running the main matching function. This means that a special item
1625  such as (*COMMIT) at the start of a pattern is not considered until after a  such as (*COMMIT) at the start of a pattern is not considered until after a
1626  suitable starting point for the match has been found. When callouts are in use,  suitable starting point for the match has been found. When callouts or (*MARK)
1627  these "start-up" optimizations can cause them to be skipped if the pattern is  items are in use, these "start-up" optimizations can cause them to be skipped
1628  never actually used. The PCRE_NO_START_OPTIMIZE option disables the start-up  if the pattern is never actually used. The start-up optimizations are in effect
1629  optimizations, causing performance to suffer, but ensuring that the callouts do  a pre-scan of the subject that takes place before the pattern is run.
1630  occur, and that items such as (*COMMIT) are considered at every possible  </P>
1631  starting position in the subject string.  <P>
1632    The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1633    causing performance to suffer, but ensuring that in cases where the result is
1634    "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
1635    are considered at every possible starting position in the subject string. If
1636    PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching
1637    time.
1638    </P>
1639    <P>
1640    Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
1641    Consider the pattern
1642    <pre>
1643      (*COMMIT)ABC
1644    </pre>
1645    When this is compiled, PCRE records the fact that a match must start with the
1646    character "A". Suppose the subject string is "DEFABC". The start-up
1647    optimization scans along the subject, finds "A" and runs the first match
1648    attempt from there. The (*COMMIT) item means that the pattern must match the
1649    current starting position, which in this case, it does. However, if the same
1650    match is run with PCRE_NO_START_OPTIMIZE set, the initial scan along the
1651    subject string does not happen. The first match attempt is run starting from
1652    "D" and when this fails, (*COMMIT) prevents any further matches being tried, so
1653    the overall result is "no match". If the pattern is studied, more start-up
1654    optimizations may be used. For example, a minimum length for the subject may be
1655    recorded. Consider the pattern
1656    <pre>
1657      (*MARK:A)(X|Y)
1658    </pre>
1659    The minimum length for a match is one character. If the subject is "ABC", there
1660    will be attempts to match "ABC", "BC", "C", and then finally an empty string.
1661    If the pattern is studied, the final attempt does not take place, because PCRE
1662    knows that the subject is too short, and so the (*MARK) is never encountered.
1663    In this case, studying the pattern does not affect the overall match result,
1664    which is still "no match", but it does affect the auxiliary information that is
1665    returned.
1666  <pre>  <pre>
1667    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1668  </pre>  </pre>
# Line 1461  strings in the Line 1675  strings in the
1675  in the main  in the main
1676  <a href="pcre.html"><b>pcre</b></a>  <a href="pcre.html"><b>pcre</b></a>
1677  page. If an invalid UTF-8 sequence of bytes is found, <b>pcre_exec()</b> returns  page. If an invalid UTF-8 sequence of bytes is found, <b>pcre_exec()</b> returns
1678  the error PCRE_ERROR_BADUTF8. If <i>startoffset</i> contains an invalid value,  the error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is
1679  PCRE_ERROR_BADUTF8_OFFSET is returned.  a truncated UTF-8 character at the end of the subject, PCRE_ERROR_SHORTUTF8. In
1680    both cases, information about the precise nature of the error may also be
1681    returned (see the descriptions of these errors in the section entitled \fIError
1682    return values from\fP <b>pcre_exec()</b>
1683    <a href="#errorlist">below).</a>
1684    If <i>startoffset</i> contains a value that does not point to the start of a
1685    UTF-8 character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
1686    returned.
1687  </P>  </P>
1688  <P>  <P>
1689  If you already know that your subject is valid, and you want to skip these  If you already know that your subject is valid, and you want to skip these
# Line 1470  checks for performance reasons, you can Line 1691  checks for performance reasons, you can
1691  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
1692  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
1693  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
1694  the value of <i>startoffset</i> points to the start of a UTF-8 character. When  the value of <i>startoffset</i> points to the start of a UTF-8 character (or the
1695  PCRE_NO_UTF8_CHECK is set, the effect of passing an invalid UTF-8 string as a  end of the subject). When PCRE_NO_UTF8_CHECK is set, the effect of passing an
1696  subject, or a value of <i>startoffset</i> that does not point to the start of a  invalid UTF-8 string as a subject or an invalid value of <i>startoffset</i> is
1697  UTF-8 character, is undefined. Your program may crash.  undefined. Your program may crash.
1698  <pre>  <pre>
1699    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
1700    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
# Line 1482  These options turn on the partial matchi Line 1703  These options turn on the partial matchi
1703  compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match  compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match
1704  occurs if the end of the subject string is reached successfully, but there are  occurs if the end of the subject string is reached successfully, but there are
1705  not enough subject characters to complete the match. If this happens when  not enough subject characters to complete the match. If this happens when
1706  PCRE_PARTIAL_HARD is set, <b>pcre_exec()</b> immediately returns  PCRE_PARTIAL_SOFT (but not PCRE_PARTIAL_HARD) is set, matching continues by
1707  PCRE_ERROR_PARTIAL. Otherwise, if PCRE_PARTIAL_SOFT is set, matching continues  testing any remaining alternatives. Only if no complete match can be found is
1708  by testing any other alternatives. Only if they all fail is PCRE_ERROR_PARTIAL  PCRE_ERROR_PARTIAL returned instead of PCRE_ERROR_NOMATCH. In other words,
1709  returned (instead of PCRE_ERROR_NOMATCH). The portion of the string that  PCRE_PARTIAL_SOFT says that the caller is prepared to handle a partial match,
1710  was inspected when the partial match was found is set as the first matching  but only if no complete match can be found.
1711  string. There is a more detailed discussion in the  </P>
1712    <P>
1713    If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a
1714    partial match is found, <b>pcre_exec()</b> immediately returns
1715    PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,
1716    when PCRE_PARTIAL_HARD is set, a partial match is considered to be more
1717    important that an alternative complete match.
1718    </P>
1719    <P>
1720    In both cases, the portion of the string that was inspected when the partial
1721    match was found is set as the first matching string. There is a more detailed
1722    discussion of partial and multi-segment matching, with examples, in the
1723  <a href="pcrepartial.html"><b>pcrepartial</b></a>  <a href="pcrepartial.html"><b>pcrepartial</b></a>
1724  documentation.  documentation.
1725  </P>  </P>
# Line 1497  The string to be matched by pcre_exec Line 1729  The string to be matched by pcre_exec
1729  <P>  <P>
1730  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
1731  <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
1732  in <i>startoffset</i>. In UTF-8 mode, the byte offset must point to the start of  in <i>startoffset</i>. If this is negative or greater than the length of the
1733  a UTF-8 character. Unlike the pattern string, the subject may contain binary  subject, <b>pcre_exec()</b> returns PCRE_ERROR_BADOFFSET. When the starting
1734  zero bytes. When the starting offset is zero, the search for a match starts at  offset is zero, the search for a match starts at the beginning of the subject,
1735  the beginning of the subject, and this is by far the most common case.  and this is by far the most common case. In UTF-8 mode, the byte offset must
1736    point to the start of a UTF-8 character (or the end of the subject). Unlike the
1737    pattern string, the subject may contain binary zero bytes.
1738  </P>  </P>
1739  <P>  <P>
1740  A non-zero starting offset is useful when searching for another match in the  A non-zero starting offset is useful when searching for another match in the
# Line 1522  set to 4, it finds the second occurrence Line 1756  set to 4, it finds the second occurrence
1756  behind the starting point to discover that it is preceded by a letter.  behind the starting point to discover that it is preceded by a letter.
1757  </P>  </P>
1758  <P>  <P>
1759    Finding all the matches in a subject is tricky when the pattern can match an
1760    empty string. It is possible to emulate Perl's /g behaviour by first trying the
1761    match again at the same offset, with the PCRE_NOTEMPTY_ATSTART and
1762    PCRE_ANCHORED options, and then if that fails, advancing the starting offset
1763    and trying an ordinary match again. There is some code that demonstrates how to
1764    do this in the
1765    <a href="pcredemo.html"><b>pcredemo</b></a>
1766    sample program. In the most general case, you have to check to see if the
1767    newline convention recognizes CRLF as a newline, and if so, and the current
1768    character is CR followed by LF, advance the starting offset by two characters
1769    instead of one.
1770    </P>
1771    <P>
1772  If a non-zero starting offset is passed when the pattern is anchored, one  If a non-zero starting offset is passed when the pattern is anchored, one
1773  attempt to match at the given offset is made. This can only succeed if the  attempt to match at the given offset is made. This can only succeed if the
1774  pattern does not require the match to be at the start of the subject.  pattern does not require the match to be at the start of the subject.
# Line 1576  string that it matched that is returned. Line 1823  string that it matched that is returned.
1823  <P>  <P>
1824  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
1825  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
1826  returns a value of zero. If the substring offsets are not of interest,  returns a value of zero. If neither the actual string matched not any captured
1827  <b>pcre_exec()</b> may be called with <i>ovector</i> passed as NULL and  substrings are of interest, <b>pcre_exec()</b> may be called with <i>ovector</i>
1828  <i>ovecsize</i> as zero. However, if the pattern contains back references and  passed as NULL and <i>ovecsize</i> as zero. However, if the pattern contains
1829  the <i>ovector</i> is not big enough to remember the related substrings, PCRE  back references and the <i>ovector</i> is not big enough to remember the related
1830  has to get additional memory for use during matching. Thus it is usually  substrings, PCRE has to get additional memory for use during matching. Thus it
1831  advisable to supply an <i>ovector</i>.  is usually advisable to supply an <i>ovector</i> of reasonable size.
1832    </P>
1833    <P>
1834    There are some cases where zero is returned (indicating vector overflow) when
1835    in fact the vector is exactly the right size for the final match. For example,
1836    consider the pattern
1837    <pre>
1838      (a)(?:(b)c|bd)
1839    </pre>
1840    If a vector of 6 elements (allowing for only 1 captured substring) is given
1841    with subject string "abd", <b>pcre_exec()</b> will try to set the second
1842    captured string, thereby recording a vector overflow, before failing to match
1843    "c" and backing up to try the second alternative. The zero return, however,
1844    does correctly indicate that the maximum number of slots (namely 2) have been
1845    filled. In similar cases where there is temporary overflow, but the final
1846    number of used slots is actually less than the maximum, a non-zero value is
1847    returned.
1848  </P>  </P>
1849  <P>  <P>
1850  The <b>pcre_fullinfo()</b> function can be used to find out how many capturing  The <b>pcre_fullinfo()</b> function can be used to find out how many capturing
# Line 1602  Offset values that correspond to unused Line 1865  Offset values that correspond to unused
1865  expression are also set to -1. For example, if the string "abc" is matched  expression are also set to -1. For example, if the string "abc" is matched
1866  against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not matched. The  against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not matched. The
1867  return from the function is 2, because the highest used capturing subpattern  return from the function is 2, because the highest used capturing subpattern
1868  number is 1. However, you can refer to the offsets for the second and third  number is 1, and the offsets for for the second and third capturing subpatterns
1869  capturing subpatterns if you wish (assuming the vector is large enough, of  (assuming the vector is large enough, of course) are set to -1.
1870  course).  </P>
1871    <P>
1872    <b>Note</b>: Elements in the first two-thirds of <i>ovector</i> that do not
1873    correspond to capturing parentheses in the pattern are never changed. That is,
1874    if a pattern contains <i>n</i> capturing parentheses, no more than
1875    <i>ovector[0]</i> to <i>ovector[2n+1]</i> are set by <b>pcre_exec()</b>. The other
1876    elements (in the first two-thirds) retain whatever values they previously had.
1877  </P>  </P>
1878  <P>  <P>
1879  Some convenience functions are provided for extracting the captured substrings  Some convenience functions are provided for extracting the captured substrings
# Line 1678  documentation for details. Line 1947  documentation for details.
1947  <pre>  <pre>
1948    PCRE_ERROR_BADUTF8        (-10)    PCRE_ERROR_BADUTF8        (-10)
1949  </pre>  </pre>
1950  A string that contains an invalid UTF-8 byte sequence was passed as a subject.  A string that contains an invalid UTF-8 byte sequence was passed as a subject,
1951    and the PCRE_NO_UTF8_CHECK option was not set. If the size of the output vector
1952    (<i>ovecsize</i>) is at least 2, the byte offset to the start of the the invalid
1953    UTF-8 character is placed in the first element, and a reason code is placed in
1954    the second element. The reason codes are listed in the
1955    <a href="#badutf8reasons">following section.</a>
1956    For backward compatibility, if PCRE_PARTIAL_HARD is set and the problem is a
1957    truncated UTF-8 character at the end of the subject (reason codes 1 to 5),
1958    PCRE_ERROR_SHORTUTF8 is returned instead of PCRE_ERROR_BADUTF8.
1959  <pre>  <pre>
1960    PCRE_ERROR_BADUTF8_OFFSET (-11)    PCRE_ERROR_BADUTF8_OFFSET (-11)
1961  </pre>  </pre>
1962  The UTF-8 byte sequence that was passed as a subject was valid, but the value  The UTF-8 byte sequence that was passed as a subject was checked and found to
1963  of <i>startoffset</i> did not point to the beginning of a UTF-8 character.  be valid (the PCRE_NO_UTF8_CHECK option was not set), but the value of
1964    <i>startoffset</i> did not point to the beginning of a UTF-8 character or the
1965    end of the subject.
1966  <pre>  <pre>
1967    PCRE_ERROR_PARTIAL        (-12)    PCRE_ERROR_PARTIAL        (-12)
1968  </pre>  </pre>
# Line 1716  description above. Line 1995  description above.
1995    PCRE_ERROR_BADNEWLINE     (-23)    PCRE_ERROR_BADNEWLINE     (-23)
1996  </pre>  </pre>
1997  An invalid combination of PCRE_NEWLINE_<i>xxx</i> options was given.  An invalid combination of PCRE_NEWLINE_<i>xxx</i> options was given.
1998    <pre>
1999      PCRE_ERROR_BADOFFSET      (-24)
2000    </pre>
2001    The value of <i>startoffset</i> was negative or greater than the length of the
2002    subject, that is, the value in <i>length</i>.
2003    <pre>
2004      PCRE_ERROR_SHORTUTF8      (-25)
2005    </pre>
2006    This error is returned instead of PCRE_ERROR_BADUTF8 when the subject string
2007    ends with a truncated UTF-8 character and the PCRE_PARTIAL_HARD option is set.
2008    Information about the failure is returned as for PCRE_ERROR_BADUTF8. It is in
2009    fact sufficient to detect this case, but this special error code for
2010    PCRE_PARTIAL_HARD precedes the implementation of returned information; it is
2011    retained for backwards compatibility.
2012    <pre>
2013      PCRE_ERROR_RECURSELOOP    (-26)
2014    </pre>
2015    This error is returned when <b>pcre_exec()</b> detects a recursion loop within
2016    the pattern. Specifically, it means that either the whole pattern or a
2017    subpattern has been called recursively for the second time at the same position
2018    in the subject string. Some simple patterns that might do this are detected and
2019    faulted at compile time, but more complicated cases, in particular mutual
2020    recursions between two different subpatterns, cannot be detected until run
2021    time.
2022    <pre>
2023      PCRE_ERROR_JIT_STACKLIMIT (-27)
2024    </pre>
2025    This error is returned when a pattern that was successfully studied using the
2026    PCRE_STUDY_JIT_COMPILE option is being matched, but the memory available for
2027    the just-in-time processing stack is not large enough. See the
2028    <a href="pcrejit.html"><b>pcrejit</b></a>
2029    documentation for more details.
2030  </P>  </P>
2031  <P>  <P>
2032  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>.
2033    <a name="badutf8reasons"></a></P>
2034    <br><b>
2035    Reason codes for invalid UTF-8 strings
2036    </b><br>
2037    <P>
2038    When <b>pcre_exec()</b> returns either PCRE_ERROR_BADUTF8 or
2039    PCRE_ERROR_SHORTUTF8, and the size of the output vector (<i>ovecsize</i>) is at
2040    least 2, the offset of the start of the invalid UTF-8 character is placed in
2041    the first output vector element (<i>ovector[0]</i>) and a reason code is placed
2042    in the second element (<i>ovector[1]</i>). The reason codes are given names in
2043    the <b>pcre.h</b> header file:
2044    <pre>
2045      PCRE_UTF8_ERR1
2046      PCRE_UTF8_ERR2
2047      PCRE_UTF8_ERR3
2048      PCRE_UTF8_ERR4
2049      PCRE_UTF8_ERR5
2050    </pre>
2051    The string ends with a truncated UTF-8 character; the code specifies how many
2052    bytes are missing (1 to 5). Although RFC 3629 restricts UTF-8 characters to be
2053    no longer than 4 bytes, the encoding scheme (originally defined by RFC 2279)
2054    allows for up to 6 bytes, and this is checked first; hence the possibility of
2055    4 or 5 missing bytes.
2056    <pre>
2057      PCRE_UTF8_ERR6
2058      PCRE_UTF8_ERR7
2059      PCRE_UTF8_ERR8
2060      PCRE_UTF8_ERR9
2061      PCRE_UTF8_ERR10
2062    </pre>
2063    The two most significant bits of the 2nd, 3rd, 4th, 5th, or 6th byte of the
2064    character do not have the binary value 0b10 (that is, either the most
2065    significant bit is 0, or the next bit is 1).
2066    <pre>
2067      PCRE_UTF8_ERR11
2068      PCRE_UTF8_ERR12
2069    </pre>
2070    A character that is valid by the RFC 2279 rules is either 5 or 6 bytes long;
2071    these code points are excluded by RFC 3629.
2072    <pre>
2073      PCRE_UTF8_ERR13
2074    </pre>
2075    A 4-byte character has a value greater than 0x10fff; these code points are
2076    excluded by RFC 3629.
2077    <pre>
2078      PCRE_UTF8_ERR14
2079    </pre>
2080    A 3-byte character has a value in the range 0xd800 to 0xdfff; this range of
2081    code points are reserved by RFC 3629 for use with UTF-16, and so are excluded
2082    from UTF-8.
2083    <pre>
2084      PCRE_UTF8_ERR15
2085      PCRE_UTF8_ERR16
2086      PCRE_UTF8_ERR17
2087      PCRE_UTF8_ERR18
2088      PCRE_UTF8_ERR19
2089    </pre>
2090    A 2-, 3-, 4-, 5-, or 6-byte character is "overlong", that is, it codes for a
2091    value that can be represented by fewer bytes, which is invalid. For example,
2092    the two bytes 0xc0, 0xae give the value 0x2e, whose correct coding uses just
2093    one byte.
2094    <pre>
2095      PCRE_UTF8_ERR20
2096    </pre>
2097    The two most significant bits of the first byte of a character have the binary
2098    value 0b10 (that is, the most significant bit is 1 and the second is 0). Such a
2099    byte can only validly occur as the second or subsequent byte of a multi-byte
2100    character.
2101    <pre>
2102      PCRE_UTF8_ERR21
2103    </pre>
2104    The first byte of a character has the value 0xfe or 0xff. These values can
2105    never occur in a valid UTF-8 string.
2106  </P>  </P>
2107  <br><a name="SEC15" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a><br>  <br><a name="SEC17" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a><br>
2108  <P>  <P>
2109  <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>
2110  <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 1815  linked via a special interface to anothe Line 2199  linked via a special interface to anothe
2199  <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
2200  provided.  provided.
2201  </P>  </P>
2202  <br><a name="SEC16" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a><br>  <br><a name="SEC18" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a><br>
2203  <P>  <P>
2204  <b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b>  <b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b>
2205  <b>const char *<i>name</i>);</b>  <b>const char *<i>name</i>);</b>
# Line 1879  names are not included in the compiled c Line 2263  names are not included in the compiled c
2263  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
2264  same number causes an error at compile time.  same number causes an error at compile time.
2265  </P>  </P>
2266  <br><a name="SEC17" href="#TOC1">DUPLICATE SUBPATTERN NAMES</a><br>  <br><a name="SEC19" href="#TOC1">DUPLICATE SUBPATTERN NAMES</a><br>
2267  <P>  <P>
2268  <b>int pcre_get_stringtable_entries(const pcre *<i>code</i>,</b>  <b>int pcre_get_stringtable_entries(const pcre *<i>code</i>,</b>
2269  <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 1912  fourth are pointers to variables which a Line 2296  fourth are pointers to variables which a
2296  has run, they point to the first and last entries in the name-to-number table  has run, they point to the first and last entries in the name-to-number table
2297  for the given name. The function itself returns the length of each entry, or  for the given name. The function itself returns the length of each entry, or
2298  PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is  PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is
2299  described above in the section entitled <i>Information about a pattern</i>.  described above in the section entitled <i>Information about a pattern</i>
2300    <a href="#infoaboutpattern">above.</a>
2301  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
2302  numbers, and hence the captured data, if any.  numbers, and hence the captured data, if any.
2303  </P>  </P>
2304  <br><a name="SEC18" href="#TOC1">FINDING ALL POSSIBLE MATCHES</a><br>  <br><a name="SEC20" href="#TOC1">FINDING ALL POSSIBLE MATCHES</a><br>
2305  <P>  <P>
2306  The traditional matching function uses a similar algorithm to Perl, which stops  The traditional matching function uses a similar algorithm to Perl, which stops
2307  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 1935  substring. Then return 1, which forces < Line 2320  substring. Then return 1, which forces <
2320  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>
2321  will yield PCRE_ERROR_NOMATCH.  will yield PCRE_ERROR_NOMATCH.
2322  <a name="dfamatch"></a></P>  <a name="dfamatch"></a></P>
2323  <br><a name="SEC19" href="#TOC1">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a><br>  <br><a name="SEC21" href="#TOC1">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a><br>
2324  <P>  <P>
2325  <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>
2326  <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 2010  is converted into PCRE_ERROR_PARTIAL if Line 2395  is converted into PCRE_ERROR_PARTIAL if
2395  there have been no complete matches, but there is still at least one matching  there have been no complete matches, but there is still at least one matching
2396  possibility. The portion of the string that was inspected when the longest  possibility. The portion of the string that was inspected when the longest
2397  partial match was found is set as the first matching string in both cases.  partial match was found is set as the first matching string in both cases.
2398    There is a more detailed discussion of partial and multi-segment matching, with
2399    examples, in the
2400    <a href="pcrepartial.html"><b>pcrepartial</b></a>
2401    documentation.
2402  <pre>  <pre>
2403    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
2404  </pre>  </pre>
# Line 2062  returns data, even though the meaning of Line 2451  returns data, even though the meaning of
2451  The strings are returned in reverse order of length; that is, the longest  The strings are returned in reverse order of length; that is, the longest
2452  matching string is given first. If there were too many matches to fit into  matching string is given first. If there were too many matches to fit into
2453  <i>ovector</i>, the yield of the function is zero, and the vector is filled with  <i>ovector</i>, the yield of the function is zero, and the vector is filled with
2454  the longest matches.  the longest matches. Unlike <b>pcre_exec()</b>, <b>pcre_dfa_exec()</b> can use
2455    the entire <i>ovector</i> for returning matched strings.
2456  </P>  </P>
2457  <br><b>  <br><b>
2458  Error returns from <b>pcre_dfa_exec()</b>  Error returns from <b>pcre_dfa_exec()</b>
# Line 2089  group. These are not supported. Line 2479  group. These are not supported.
2479    PCRE_ERROR_DFA_UMLIMIT    (-18)    PCRE_ERROR_DFA_UMLIMIT    (-18)
2480  </pre>  </pre>
2481  This return is given if <b>pcre_dfa_exec()</b> is called with an <i>extra</i>  This return is given if <b>pcre_dfa_exec()</b> is called with an <i>extra</i>
2482  block that contains a setting of the <i>match_limit</i> field. This is not  block that contains a setting of the <i>match_limit</i> or
2483  supported (it is meaningless).  <i>match_limit_recursion</i> fields. This is not supported (these fields are
2484    meaningless for DFA matching).
2485  <pre>  <pre>
2486    PCRE_ERROR_DFA_WSSIZE     (-19)    PCRE_ERROR_DFA_WSSIZE     (-19)
2487  </pre>  </pre>
# Line 2104  recursively, using private vectors for < Line 2495  recursively, using private vectors for <
2495  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
2496  extremely rare, as a vector of size 1000 is used.  extremely rare, as a vector of size 1000 is used.
2497  </P>  </P>
2498  <br><a name="SEC20" href="#TOC1">SEE ALSO</a><br>  <br><a name="SEC22" href="#TOC1">SEE ALSO</a><br>
2499  <P>  <P>
2500  <b>pcrebuild</b>(3), <b>pcrecallout</b>(3), <b>pcrecpp(3)</b>(3),  <b>pcrebuild</b>(3), <b>pcrecallout</b>(3), <b>pcrecpp(3)</b>(3),
2501  <b>pcrematching</b>(3), <b>pcrepartial</b>(3), <b>pcreposix</b>(3),  <b>pcrematching</b>(3), <b>pcrepartial</b>(3), <b>pcreposix</b>(3),
2502  <b>pcreprecompile</b>(3), <b>pcresample</b>(3), <b>pcrestack</b>(3).  <b>pcreprecompile</b>(3), <b>pcresample</b>(3), <b>pcrestack</b>(3).
2503  </P>  </P>
2504  <br><a name="SEC21" href="#TOC1">AUTHOR</a><br>  <br><a name="SEC23" href="#TOC1">AUTHOR</a><br>
2505  <P>  <P>
2506  Philip Hazel  Philip Hazel
2507  <br>  <br>
# Line 2119  University Computing Service Line 2510  University Computing Service
2510  Cambridge CB2 3QH, England.  Cambridge CB2 3QH, England.
2511  <br>  <br>
2512  </P>  </P>
2513  <br><a name="SEC22" href="#TOC1">REVISION</a><br>  <br><a name="SEC24" href="#TOC1">REVISION</a><br>
2514  <P>  <P>
2515  Last updated: 15 June 2010  Last updated: 02 December 2011
2516  <br>  <br>
2517  Copyright &copy; 1997-2010 University of Cambridge.  Copyright &copy; 1997-2011 University of Cambridge.
2518  <br>  <br>
2519  <p>  <p>
2520  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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