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revision 542 by ph10, Tue Jun 15 08:49:47 2010 UTC revision 745 by ph10, Mon Nov 14 11:41:03 2011 UTC
# Line 1  Line 1 
1  .TH PCREAPI 3  .TH PCREAPI 3
2  .SH NAME  .SH NAME
3  PCRE - Perl-compatible regular expressions  PCRE - Perl-compatible regular expressions
4  .SH "PCRE NATIVE API"  .SH "PCRE NATIVE API BASIC FUNCTIONS"
5  .rs  .rs
6  .sp  .sp
7  .B #include <pcre.h>  .B #include <pcre.h>
# Line 25  PCRE - Perl-compatible regular expressio Line 25  PCRE - Perl-compatible regular expressio
25  .ti +5n  .ti +5n
26  .B const char **\fIerrptr\fP);  .B const char **\fIerrptr\fP);
27  .PP  .PP
28    .B void pcre_free_study(pcre_extra *\fIextra\fP);
29    .PP
30  .B int pcre_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"  .B int pcre_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
31  .ti +5n  .ti +5n
32  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
33  .ti +5n  .ti +5n
34  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);
35    .
36    .
37    .SH "PCRE NATIVE API AUXILIARY FUNCTIONS"
38    .rs
39    .sp
40    .B pcre_jit_stack *pcre_jit_stack_alloc(int \fIstartsize\fP, int \fImaxsize\fP);
41    .PP
42    .B void pcre_jit_stack_free(pcre_jit_stack *\fIstack\fP);
43    .PP
44    .B void pcre_assign_jit_stack(pcre_extra *\fIextra\fP,
45    .ti +5n
46    .B pcre_jit_callback \fIcallback\fP, void *\fIdata\fP);
47  .PP  .PP
48  .B int pcre_dfa_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"  .B int pcre_dfa_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
49  .ti +5n  .ti +5n
# Line 97  PCRE - Perl-compatible regular expressio Line 111  PCRE - Perl-compatible regular expressio
111  .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);  .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);
112  .PP  .PP
113  .B char *pcre_version(void);  .B char *pcre_version(void);
114  .PP  .
115    .
116    .SH "PCRE NATIVE API INDIRECTED FUNCTIONS"
117    .rs
118    .sp
119  .B void *(*pcre_malloc)(size_t);  .B void *(*pcre_malloc)(size_t);
120  .PP  .PP
121  .B void (*pcre_free)(void *);  .B void (*pcre_free)(void *);
# Line 114  PCRE - Perl-compatible regular expressio Line 132  PCRE - Perl-compatible regular expressio
132  .sp  .sp
133  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
134  also some wrapper functions that correspond to the POSIX regular expression  also some wrapper functions that correspond to the POSIX regular expression
135  API. These are described in the  API, but they do not give access to all the functionality. They are described
136    in the
137  .\" HREF  .\" HREF
138  \fBpcreposix\fP  \fBpcreposix\fP
139  .\"  .\"
140  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++
141  wrapper is distributed with PCRE. It is documented in the  wrapper is also distributed with PCRE. It is documented in the
142  .\" HREF  .\" HREF
143  \fBpcrecpp\fP  \fBpcrecpp\fP
144  .\"  .\"
# Line 152  documentation, and the Line 171  documentation, and the
171  .\"  .\"
172  documentation describes how to compile and run it.  documentation describes how to compile and run it.
173  .P  .P
174    Just-in-time compiler support is an optional feature of PCRE that can be built
175    in appropriate hardware environments. It greatly speeds up the matching
176    performance of many patterns. Simple programs can easily request that it be
177    used if available, by setting an option that is ignored when it is not
178    relevant. More complicated programs might need to make use of the functions
179    \fBpcre_jit_stack_alloc()\fP, \fBpcre_jit_stack_free()\fP, and
180    \fBpcre_assign_jit_stack()\fP in order to control the JIT code's memory usage.
181    These functions are discussed in the
182    .\" HREF
183    \fBpcrejit\fP
184    .\"
185    documentation.
186    .P
187  A second matching function, \fBpcre_dfa_exec()\fP, which is not  A second matching function, \fBpcre_dfa_exec()\fP, which is not
188  Perl-compatible, is also provided. This uses a different algorithm for the  Perl-compatible, is also provided. This uses a different algorithm for the
189  matching. The alternative algorithm finds all possible matches (at a given  matching. The alternative algorithm finds all possible matches (at a given
# Line 282  callout function pointed to by \fBpcre_c Line 314  callout function pointed to by \fBpcre_c
314  .P  .P
315  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
316  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.
317    .P
318    If the just-in-time optimization feature is being used, it needs separate
319    memory stack areas for each thread. See the
320    .\" HREF
321    \fBpcrejit\fP
322    .\"
323    documentation for more details.
324  .  .
325  .  .
326  .SH "SAVING PRECOMPILED PATTERNS FOR LATER USE"  .SH "SAVING PRECOMPILED PATTERNS FOR LATER USE"
# Line 324  otherwise it is set to zero. Line 363  otherwise it is set to zero.
363  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
364  properties is available; otherwise it is set to zero.  properties is available; otherwise it is set to zero.
365  .sp  .sp
366      PCRE_CONFIG_JIT
367    .sp
368    The output is an integer that is set to one if support for just-in-time
369    compiling is available; otherwise it is set to zero.
370    .sp
371    PCRE_CONFIG_NEWLINE    PCRE_CONFIG_NEWLINE
372  .sp  .sp
373  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 428  within the pattern (see the detailed des Line 472  within the pattern (see the detailed des
472  documentation). For those options that can be different in different parts of  documentation). For those options that can be different in different parts of
473  the pattern, the contents of the \fIoptions\fP argument specifies their  the pattern, the contents of the \fIoptions\fP argument specifies their
474  settings at the start of compilation and execution. The PCRE_ANCHORED,  settings at the start of compilation and execution. The PCRE_ANCHORED,
475  PCRE_BSR_\fIxxx\fP, and PCRE_NEWLINE_\fIxxx\fP options can be set at the time  PCRE_BSR_\fIxxx\fP, PCRE_NEWLINE_\fIxxx\fP, PCRE_NO_UTF8_CHECK, and
476  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
477    compile time.
478  .P  .P
479  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
480  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
481  NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual  NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual
482  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
483  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
484  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
485  the variable pointed to by \fIerroffset\fP, which must not be NULL. If it is,  variable pointed to by \fIerroffset\fP, which must not be NULL (if it is, an
486  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
487  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
488  set to the end of the pattern.  detected until checks are carried out when the whole pattern has been scanned;
489    in these cases the offset passed back is the length of the pattern.
490    .P
491    Note that the offset is in bytes, not characters, even in UTF-8 mode. It may
492    sometimes point into the middle of a UTF-8 character.
493  .P  .P
494  If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the  If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the
495  \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is  \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is
# Line 519  pattern. Line 568  pattern.
568  .sp  .sp
569    PCRE_DOTALL    PCRE_DOTALL
570  .sp  .sp
571  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
572  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
573  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,
574  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
575  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
576  the setting of this option.  (?s) option setting. A negative class such as [^a] always matches newline
577    characters, independent of the setting of this option.
578  .sp  .sp
579    PCRE_DUPNAMES    PCRE_DUPNAMES
580  .sp  .sp
# Line 546  unescaped # outside a character class an Line 596  unescaped # outside a character class an
596  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
597  pattern by a (?x) option setting.  pattern by a (?x) option setting.
598  .P  .P
599    Which characters are interpreted as newlines is controlled by the options
600    passed to \fBpcre_compile()\fP or by a special sequence at the start of the
601    pattern, as described in the section entitled
602    .\" HTML <a href="pcrepattern.html#newlines">
603    .\" </a>
604    "Newline conventions"
605    .\"
606    in the \fBpcrepattern\fP documentation. Note that the end of this type of
607    comment is a literal newline sequence in the pattern; escape sequences that
608    happen to represent a newline do not count.
609    .P
610  This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
611  Note, however, that this applies only to data characters. Whitespace characters  Note, however, that this applies only to data characters. Whitespace characters
612  may never appear within special character sequences in a pattern, for example  may never appear within special character sequences in a pattern, for example
613  within the sequence (?( which introduces a conditional subpattern.  within the sequence (?( that introduces a conditional subpattern.
614  .sp  .sp
615    PCRE_EXTRA    PCRE_EXTRA
616  .sp  .sp
# Line 582  character). Thus, the pattern AB]CD beco Line 643  character). Thus, the pattern AB]CD beco
643  string (by default this causes the current matching alternative to fail). A  string (by default this causes the current matching alternative to fail). A
644  pattern such as (\e1)(a) succeeds when this option is set (assuming it can find  pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
645  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.
646    .P
647    (3) \eU matches an upper case "U" character; by default \eU causes a compile
648    time error (Perl uses \eU to upper case subsequent characters).
649    .P
650    (4) \eu matches a lower case "u" character unless it is followed by four
651    hexadecimal digits, in which case the hexadecimal number defines the code point
652    to match. By default, \eu causes a compile time error (Perl uses it to upper
653    case the following character).
654    .P
655    (5) \ex matches a lower case "x" character unless it is followed by two
656    hexadecimal digits, in which case the hexadecimal number defines the code point
657    to match. By default, as in Perl, a hexadecimal number is always expected after
658    \ex, but it may have zero, one, or two digits (so, for example, \exz matches a
659    binary zero character followed by z).
660  .sp  .sp
661    PCRE_MULTILINE    PCRE_MULTILINE
662  .sp  .sp
# Line 624  option, the combination may or may not b Line 699  option, the combination may or may not b
699  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but
700  other combinations may yield unused numbers and cause an error.  other combinations may yield unused numbers and cause an error.
701  .P  .P
702  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
703  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,
704  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
705  line break sequence. In other circumstances, line break sequences are treated  indicates a comment that lasts until after the next line break sequence. In
706  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
707  as whitespace characters and are therefore ignored.  data.
708  .P  .P
709  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
710  for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.  for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.
# Line 642  were followed by ?: but named parenthese Line 717  were followed by ?: but named parenthese
717  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
718  in Perl.  in Perl.
719  .sp  .sp
720      NO_START_OPTIMIZE
721    .sp
722    This is an option that acts at matching time; that is, it is really an option
723    for \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. If it is set at compile time,
724    it is remembered with the compiled pattern and assumed at matching time. For
725    details see the discussion of PCRE_NO_START_OPTIMIZE
726    .\" HTML <a href="#execoptions">
727    .\" </a>
728    below.
729    .\"
730    .sp
731    PCRE_UCP    PCRE_UCP
732  .sp  .sp
733  This option changes the way PCRE processes \eb, \ed, \es, \ew, and some of the  This option changes the way PCRE processes \eB, \eb, \eD, \ed, \eS, \es, \eW,
734  POSIX character classes. By default, only ASCII characters are recognized, but  \ew, and some of the POSIX character classes. By default, only ASCII characters
735  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
736  More details are given in the section on  classify characters. More details are given in the section on
737  .\" HTML <a href="pcre.html#genericchartypes">  .\" HTML <a href="pcre.html#genericchartypes">
738  .\" </a>  .\" </a>
739  generic character types  generic character types
# Line 673  of UTF-8 characters instead of single-by Line 759  of UTF-8 characters instead of single-by
759  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
760  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
761  behaviour of PCRE are given in the  behaviour of PCRE are given in the
 .\" HTML <a href="pcre.html#utf8support">  
 .\" </a>  
 section on UTF-8 support  
 .\"  
 in the main  
762  .\" HREF  .\" HREF
763  \fBpcre\fP  \fBpcreunicode\fP
764  .\"  .\"
765  page.  page.
766  .sp  .sp
# Line 749  out of use. To avoid confusion, they hav Line 830  out of use. To avoid confusion, they hav
830    34  character value in \ex{...} sequence is too large    34  character value in \ex{...} sequence is too large
831    35  invalid condition (?(0)    35  invalid condition (?(0)
832    36  \eC not allowed in lookbehind assertion    36  \eC not allowed in lookbehind assertion
833    37  PCRE does not support \eL, \el, \eN, \eU, or \eu    37  PCRE does not support \eL, \el, \eN{name}, \eU, or \eu
834    38  number after (?C is > 255    38  number after (?C is > 255
835    39  closing ) for (?C expected    39  closing ) for (?C expected
836    40  recursive call could loop indefinitely    40  recursive call could loop indefinitely
# Line 765  out of use. To avoid confusion, they hav Line 846  out of use. To avoid confusion, they hav
846    50  [this code is not in use]    50  [this code is not in use]
847    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 (not in UTF-8 mode)
848    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
849    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern
850            not found
851    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
852    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
853    56  inconsistent NEWLINE options    56  inconsistent NEWLINE options
# Line 778  out of use. To avoid confusion, they hav Line 860  out of use. To avoid confusion, they hav
860    62  subpattern name expected    62  subpattern name expected
861    63  digit expected after (?+    63  digit expected after (?+
862    64  ] is an invalid data character in JavaScript compatibility mode    64  ] is an invalid data character in JavaScript compatibility mode
863    65  different names for subpatterns of the same number are not allowed    65  different names for subpatterns of the same number are
864            not allowed
865    66  (*MARK) must have an argument    66  (*MARK) must have an argument
866    67  this version of PCRE is not compiled with PCRE_UCP support    67  this version of PCRE is not compiled with PCRE_UCP support
867      68  \ec must be followed by an ASCII character
868      69  \ek is not followed by a braced, angle-bracketed, or quoted name
869  .sp  .sp
870  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
871  be used if the limits were changed when PCRE was built.  be used if the limits were changed when PCRE was built.
872  .  .
873  .  .
874    .\" HTML <a name="studyingapattern"></a>
875  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
876  .rs  .rs
877  .sp  .sp
# Line 816  If studying the pattern does not produce Line 902  If studying the pattern does not produce
902  wants to pass any of the other fields to \fBpcre_exec()\fP or  wants to pass any of the other fields to \fBpcre_exec()\fP or
903  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.
904  .P  .P
905  The second argument of \fBpcre_study()\fP contains option bits. At present, no  The second argument of \fBpcre_study()\fP contains option bits. There is only
906  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
907    compiler is available, the pattern is further compiled into machine code that
908    executes much faster than the \fBpcre_exec()\fP matching function. If
909    the just-in-time compiler is not available, this option is ignored. All other
910    bits in the \fIoptions\fP argument must be zero.
911    .P
912    JIT compilation is a heavyweight optimization. It can take some time for
913    patterns to be analyzed, and for one-off matches and simple patterns the
914    benefit of faster execution might be offset by a much slower study time.
915    Not all patterns can be optimized by the JIT compiler. For those that cannot be
916    handled, matching automatically falls back to the \fBpcre_exec()\fP
917    interpreter. For more details, see the
918    .\" HREF
919    \fBpcrejit\fP
920    .\"
921    documentation.
922  .P  .P
923  The third argument for \fBpcre_study()\fP is a pointer for an error message. If  The third argument for \fBpcre_study()\fP is a pointer for an error message. If
924  studying succeeds (even if no data is returned), the variable it points to is  studying succeeds (even if no data is returned), the variable it points to is
# Line 826  static string that is part of the librar Line 927  static string that is part of the librar
927  should test the error pointer for NULL after calling \fBpcre_study()\fP, to be  should test the error pointer for NULL after calling \fBpcre_study()\fP, to be
928  sure that it has run successfully.  sure that it has run successfully.
929  .P  .P
930  This is a typical call to \fBpcre_study\fP():  When you are finished with a pattern, you can free the memory used for the
931    study data by calling \fBpcre_free_study()\fP. This function was added to the
932    API for release 8.20. For earlier versions, the memory could be freed with
933    \fBpcre_free()\fP, just like the pattern itself. This will still work in cases
934    where PCRE_STUDY_JIT_COMPILE is not used, but it is advisable to change to the
935    new function when convenient.
936    .P
937    This is a typical way in which \fBpcre_study\fP() is used (except that in a
938    real application there should be tests for errors):
939  .sp  .sp
940    pcre_extra *pe;    int rc;
941    pe = pcre_study(    pcre *re;
942      pcre_extra *sd;
943      re = pcre_compile("pattern", 0, &error, &erroroffset, NULL);
944      sd = pcre_study(
945      re,             /* result of pcre_compile() */      re,             /* result of pcre_compile() */
946      0,              /* no options exist */      0,              /* no options */
947      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
948      rc = pcre_exec(   /* see below for details of pcre_exec() options */
949        re, sd, "subject", 7, 0, 0, ovector, 30);
950      ...
951      pcre_free_study(sd);
952      pcre_free(re);
953  .sp  .sp
954  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
955  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 846  Studying a pattern is also useful for no Line 963  Studying a pattern is also useful for no
963  single fixed starting character. A bitmap of possible starting bytes is  single fixed starting character. A bitmap of possible starting bytes is
964  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
965  matching.  matching.
966    .P
967    These two optimizations apply to both \fBpcre_exec()\fP and
968    \fBpcre_dfa_exec()\fP. However, they are not used by \fBpcre_exec()\fP if
969    \fBpcre_study()\fP is called with the PCRE_STUDY_JIT_COMPILE option, and
970    just-in-time compiling is successful. The optimizations can be disabled by
971    setting the PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or
972    \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains
973    callouts or (*MARK) (which cannot be handled by the JIT compiler), and you want
974    to make use of these facilities in cases where matching fails. See the
975    discussion of PCRE_NO_START_OPTIMIZE
976    .\" HTML <a href="#execoptions">
977    .\" </a>
978    below.
979    .\"
980  .  .
981  .  .
982  .\" HTML <a name="localesupport"></a>  .\" HTML <a name="localesupport"></a>
# Line 906  one in which it was compiled. Passing ta Line 1037  one in which it was compiled. Passing ta
1037  below in the section on matching a pattern.  below in the section on matching a pattern.
1038  .  .
1039  .  .
1040    .\" HTML <a name="infoaboutpattern"></a>
1041  .SH "INFORMATION ABOUT A PATTERN"  .SH "INFORMATION ABOUT A PATTERN"
1042  .rs  .rs
1043  .sp  .sp
# Line 937  check against passing an arbitrary memor Line 1069  check against passing an arbitrary memor
1069    size_t length;    size_t length;
1070    rc = pcre_fullinfo(    rc = pcre_fullinfo(
1071      re,               /* result of pcre_compile() */      re,               /* result of pcre_compile() */
1072      pe,               /* result of pcre_study(), or NULL */      sd,               /* result of pcre_study(), or NULL */
1073      PCRE_INFO_SIZE,   /* what is required */      PCRE_INFO_SIZE,   /* what is required */
1074      &length);         /* where to put the data */      &length);         /* where to put the data */
1075  .sp  .sp
# Line 1002  Return 1 if the (?J) or (?-J) option set Line 1134  Return 1 if the (?J) or (?-J) option set
1134  0. The fourth argument should point to an \fBint\fP variable. (?J) and  0. The fourth argument should point to an \fBint\fP variable. (?J) and
1135  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
1136  .sp  .sp
1137      PCRE_INFO_JIT
1138    .sp
1139    Return 1 if the pattern was studied with the PCRE_STUDY_JIT_COMPILE option, and
1140    just-in-time compiling was successful. The fourth argument should point to an
1141    \fBint\fP variable. A return value of 0 means that JIT support is not available
1142    in this version of PCRE, or that the pattern was not studied with the
1143    PCRE_STUDY_JIT_COMPILE option, or that the JIT compiler could not handle this
1144    particular pattern. See the
1145    .\" HREF
1146    \fBpcrejit\fP
1147    .\"
1148    documentation for details of what can and cannot be handled.
1149    .sp
1150    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
1151  .sp  .sp
1152  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 1124  variable. Line 1269  variable.
1269  .sp  .sp
1270    PCRE_INFO_STUDYSIZE    PCRE_INFO_STUDYSIZE
1271  .sp  .sp
1272  Return the size of the data block pointed to by the \fIstudy_data\fP field in  Return the size of the data block pointed to by the \fIstudy_data\fP field in a
1273  a \fBpcre_extra\fP block. That is, it is the value that was passed to  \fBpcre_extra\fP block. If \fBpcre_extra\fP is NULL, or there is no study data,
1274  \fBpcre_malloc()\fP when PCRE was getting memory into which to place the data  zero is returned. The fourth argument should point to a \fBsize_t\fP variable.
1275  created by \fBpcre_study()\fP. If \fBpcre_extra\fP is NULL, or there is no  The \fIstudy_data\fP field is set by \fBpcre_study()\fP to record information
1276  study data, zero is returned. The fourth argument should point to a  that will speed up matching (see the section entitled
1277  \fBsize_t\fP variable.  .\" HTML <a href="#studyingapattern">
1278    .\" </a>
1279    "Studying a pattern"
1280    .\"
1281    above). The format of the \fIstudy_data\fP block is private, but its length
1282    is made available via this option so that it can be saved and restored (see the
1283    .\" HREF
1284    \fBpcreprecompile\fP
1285    .\"
1286    documentation for details).
1287  .  .
1288  .  .
1289  .SH "OBSOLETE INFO FUNCTION"  .SH "OBSOLETE INFO FUNCTION"
# Line 1191  is different. (This seems a highly unlik Line 1345  is different. (This seems a highly unlik
1345  The function \fBpcre_exec()\fP is called to match a subject string against a  The function \fBpcre_exec()\fP is called to match a subject string against a
1346  compiled pattern, which is passed in the \fIcode\fP argument. If the  compiled pattern, which is passed in the \fIcode\fP argument. If the
1347  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
1348  \fIextra\fP argument. This function is the main matching facility of the  \fIextra\fP argument. You can call \fBpcre_exec()\fP with the same \fIcode\fP
1349  library, and it operates in a Perl-like manner. For specialist use there is  and \fIextra\fP arguments as many times as you like, in order to match
1350  also an alternative matching function, which is described  different subject strings with the same pattern.
1351    .P
1352    This function is the main matching facility of the library, and it operates in
1353    a Perl-like manner. For specialist use there is also an alternative matching
1354    function, which is described
1355  .\" HTML <a href="#dfamatch">  .\" HTML <a href="#dfamatch">
1356  .\" </a>  .\" </a>
1357  below  below
# Line 1224  Here is an example of a simple call to \ Line 1382  Here is an example of a simple call to \
1382      ovector,        /* vector of integers for substring information */      ovector,        /* vector of integers for substring information */
1383      30);            /* number of elements (NOT size in bytes) */      30);            /* number of elements (NOT size in bytes) */
1384  .  .
1385    .
1386  .\" HTML <a name="extradata"></a>  .\" HTML <a name="extradata"></a>
1387  .SS "Extra data for \fBpcre_exec()\fR"  .SS "Extra data for \fBpcre_exec()\fR"
1388  .rs  .rs
# Line 1236  fields (not necessarily in this order): Line 1395  fields (not necessarily in this order):
1395  .sp  .sp
1396    unsigned long int \fIflags\fP;    unsigned long int \fIflags\fP;
1397    void *\fIstudy_data\fP;    void *\fIstudy_data\fP;
1398      void *\fIexecutable_jit\fP;
1399    unsigned long int \fImatch_limit\fP;    unsigned long int \fImatch_limit\fP;
1400    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1401    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
# Line 1246  The \fIflags\fP field is a bitmap that s Line 1406  The \fIflags\fP field is a bitmap that s
1406  are set. The flag bits are:  are set. The flag bits are:
1407  .sp  .sp
1408    PCRE_EXTRA_STUDY_DATA    PCRE_EXTRA_STUDY_DATA
1409      PCRE_EXTRA_EXECUTABLE_JIT
1410    PCRE_EXTRA_MATCH_LIMIT    PCRE_EXTRA_MATCH_LIMIT
1411    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1412    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1413    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1414    PCRE_EXTRA_MARK    PCRE_EXTRA_MARK
1415  .sp  .sp
1416  Other flag bits should be set to zero. The \fIstudy_data\fP field is set in the  Other flag bits should be set to zero. The \fIstudy_data\fP field and sometimes
1417  \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with  the \fIexecutable_jit\fP field are set in the \fBpcre_extra\fP block that is
1418  the appropriate flag bit. You should not set this yourself, but you may add to  returned by \fBpcre_study()\fP, together with the appropriate flag bits. You
1419  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
1420    other fields and their corresponding flag bits.
1421  .P  .P
1422  The \fImatch_limit\fP field provides a means of preventing PCRE from using up a  The \fImatch_limit\fP field provides a means of preventing PCRE from using up a
1423  vast amount of resources when running patterns that are not going to match,  vast amount of resources when running patterns that are not going to match,
1424  but which have a very large number of possibilities in their search trees. The  but which have a very large number of possibilities in their search trees. The
1425  classic example is a pattern that uses nested unlimited repeats.  classic example is a pattern that uses nested unlimited repeats.
1426  .P  .P
1427  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly  Internally, \fBpcre_exec()\fP uses a function called \fBmatch()\fP, which it
1428  (sometimes recursively). The limit set by \fImatch_limit\fP is imposed on the  calls repeatedly (sometimes recursively). The limit set by \fImatch_limit\fP is
1429  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
1430  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
1431  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
1432  string.  in the subject string.
1433    .P
1434    When \fBpcre_exec()\fP is called with a pattern that was successfully studied
1435    with the PCRE_STUDY_JIT_COMPILE option, the way that the matching is executed
1436    is entirely different. However, there is still the possibility of runaway
1437    matching that goes on for a very long time, and so the \fImatch_limit\fP value
1438    is also used in this case (but in a different way) to limit how long the
1439    matching can continue.
1440  .P  .P
1441  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
1442  default is 10 million, which handles all but the most extreme cases. You can  default is 10 million, which handles all but the most extreme cases. You can
# Line 1282  limits the depth of recursion. The recur Line 1451  limits the depth of recursion. The recur
1451  total number of calls, because not all calls to \fBmatch()\fP are recursive.  total number of calls, because not all calls to \fBmatch()\fP are recursive.
1452  This limit is of use only if it is set smaller than \fImatch_limit\fP.  This limit is of use only if it is set smaller than \fImatch_limit\fP.
1453  .P  .P
1454  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
1455  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
1456  amount of heap memory that can be used.  stack, the amount of heap memory that can be used. This limit is not relevant,
1457    and is ignored, if the pattern was successfully studied with
1458    PCRE_STUDY_JIT_COMPILE.
1459  .P  .P
1460  The default value for \fImatch_limit_recursion\fP can be set when PCRE is  The default value for \fImatch_limit_recursion\fP can be set when PCRE is
1461  built; the default default is the same value as the default for  built; the default default is the same value as the default for
# Line 1343  zero. The only bits that may be set are Line 1514  zero. The only bits that may be set are
1514  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1515  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
1516  PCRE_PARTIAL_HARD.  PCRE_PARTIAL_HARD.
1517    .P
1518    If the pattern was successfully studied with the PCRE_STUDY_JIT_COMPILE option,
1519    the only supported options for JIT execution are PCRE_NO_UTF8_CHECK,
1520    PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NOTEMPTY_ATSTART. Note in
1521    particular that partial matching is not supported. If an unsupported option is
1522    used, JIT execution is disabled and the normal interpretive code in
1523    \fBpcre_exec()\fP is run.
1524  .sp  .sp
1525    PCRE_ANCHORED    PCRE_ANCHORED
1526  .sp  .sp
# Line 1438  the Line 1616  the
1616  .\" HREF  .\" HREF
1617  \fBpcredemo\fP  \fBpcredemo\fP
1618  .\"  .\"
1619  sample program.  sample program. In the most general case, you have to check to see if the
1620    newline convention recognizes CRLF as a newline, and if so, and the current
1621    character is CR followed by LF, advance the starting offset by two characters
1622    instead of one.
1623  .sp  .sp
1624    PCRE_NO_START_OPTIMIZE    PCRE_NO_START_OPTIMIZE
1625  .sp  .sp
# Line 1446  There are a number of optimizations that Line 1627  There are a number of optimizations that
1627  a match, in order to speed up the process. For example, if it is known that an  a match, in order to speed up the process. For example, if it is known that an
1628  unanchored match must start with a specific character, it searches the subject  unanchored match must start with a specific character, it searches the subject
1629  for that character, and fails immediately if it cannot find it, without  for that character, and fails immediately if it cannot find it, without
1630  actually running the main matching function. This means that a special item  actually running the main matching function. This means that a special item
1631  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
1632  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)
1633  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
1634  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
1635  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.
1636  occur, and that items such as (*COMMIT) are considered at every possible  .P
1637  starting position in the subject string.  The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1638    causing performance to suffer, but ensuring that in cases where the result is
1639    "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
1640    are considered at every possible starting position in the subject string. If
1641    PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching
1642    time.
1643    .P
1644    Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
1645    Consider the pattern
1646    .sp
1647      (*COMMIT)ABC
1648    .sp
1649    When this is compiled, PCRE records the fact that a match must start with the
1650    character "A". Suppose the subject string is "DEFABC". The start-up
1651    optimization scans along the subject, finds "A" and runs the first match
1652    attempt from there. The (*COMMIT) item means that the pattern must match the
1653    current starting position, which in this case, it does. However, if the same
1654    match is run with PCRE_NO_START_OPTIMIZE set, the initial scan along the
1655    subject string does not happen. The first match attempt is run starting from
1656    "D" and when this fails, (*COMMIT) prevents any further matches being tried, so
1657    the overall result is "no match". If the pattern is studied, more start-up
1658    optimizations may be used. For example, a minimum length for the subject may be
1659    recorded. Consider the pattern
1660    .sp
1661      (*MARK:A)(X|Y)
1662    .sp
1663    The minimum length for a match is one character. If the subject is "ABC", there
1664    will be attempts to match "ABC", "BC", "C", and then finally an empty string.
1665    If the pattern is studied, the final attempt does not take place, because PCRE
1666    knows that the subject is too short, and so the (*MARK) is never encountered.
1667    In this case, studying the pattern does not affect the overall match result,
1668    which is still "no match", but it does affect the auxiliary information that is
1669    returned.
1670  .sp  .sp
1671    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1672  .sp  .sp
# Line 1471  in the main Line 1684  in the main
1684  \fBpcre\fP  \fBpcre\fP
1685  .\"  .\"
1686  page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns  page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1687  the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains an invalid value,  the error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is
1688  PCRE_ERROR_BADUTF8_OFFSET is returned.  a truncated UTF-8 character at the end of the subject, PCRE_ERROR_SHORTUTF8. In
1689    both cases, information about the precise nature of the error may also be
1690    returned (see the descriptions of these errors in the section entitled \fIError
1691    return values from\fP \fBpcre_exec()\fP
1692    .\" HTML <a href="#errorlist">
1693    .\" </a>
1694    below).
1695    .\"
1696    If \fIstartoffset\fP contains a value that does not point to the start of a
1697    UTF-8 character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
1698    returned.
1699  .P  .P
1700  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
1701  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when
1702  calling \fBpcre_exec()\fP. You might want to do this for the second and  calling \fBpcre_exec()\fP. You might want to do this for the second and
1703  subsequent calls to \fBpcre_exec()\fP if you are making repeated calls to find  subsequent calls to \fBpcre_exec()\fP if you are making repeated calls to find
1704  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
1705  the value of \fIstartoffset\fP points to the start of a UTF-8 character. When  the value of \fIstartoffset\fP points to the start of a UTF-8 character (or the
1706  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
1707  subject, or a value of \fIstartoffset\fP that does not point to the start of a  invalid UTF-8 string as a subject or an invalid value of \fIstartoffset\fP is
1708  UTF-8 character, is undefined. Your program may crash.  undefined. Your program may crash.
1709  .sp  .sp
1710    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
1711    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
# Line 1491  These options turn on the partial matchi Line 1714  These options turn on the partial matchi
1714  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
1715  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
1716  not enough subject characters to complete the match. If this happens when  not enough subject characters to complete the match. If this happens when
1717  PCRE_PARTIAL_HARD is set, \fBpcre_exec()\fP immediately returns  PCRE_PARTIAL_SOFT (but not PCRE_PARTIAL_HARD) is set, matching continues by
1718  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
1719  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,
1720  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,
1721  was inspected when the partial match was found is set as the first matching  but only if no complete match can be found.
1722  string. There is a more detailed discussion in the  .P
1723    If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a
1724    partial match is found, \fBpcre_exec()\fP immediately returns
1725    PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,
1726    when PCRE_PARTIAL_HARD is set, a partial match is considered to be more
1727    important that an alternative complete match.
1728    .P
1729    In both cases, the portion of the string that was inspected when the partial
1730    match was found is set as the first matching string. There is a more detailed
1731    discussion of partial and multi-segment matching, with examples, in the
1732  .\" HREF  .\" HREF
1733  \fBpcrepartial\fP  \fBpcrepartial\fP
1734  .\"  .\"
1735  documentation.  documentation.
1736  .  .
1737    .
1738  .SS "The string to be matched by \fBpcre_exec()\fP"  .SS "The string to be matched by \fBpcre_exec()\fP"
1739  .rs  .rs
1740  .sp  .sp
1741  The subject string is passed to \fBpcre_exec()\fP as a pointer in  The subject string is passed to \fBpcre_exec()\fP as a pointer in
1742  \fIsubject\fP, a length (in bytes) in \fIlength\fP, and a starting byte offset  \fIsubject\fP, a length (in bytes) in \fIlength\fP, and a starting byte offset
1743  in \fIstartoffset\fP. In UTF-8 mode, the byte offset must point to the start of  in \fIstartoffset\fP. If this is negative or greater than the length of the
1744  a UTF-8 character. Unlike the pattern string, the subject may contain binary  subject, \fBpcre_exec()\fP returns PCRE_ERROR_BADOFFSET. When the starting
1745  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,
1746  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
1747    point to the start of a UTF-8 character (or the end of the subject). Unlike the
1748    pattern string, the subject may contain binary zero bytes.
1749  .P  .P
1750  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
1751  same subject by calling \fBpcre_exec()\fP again after a previous success.  same subject by calling \fBpcre_exec()\fP again after a previous success.
# Line 1530  start of the subject, which is deemed to Line 1765  start of the subject, which is deemed to
1765  set to 4, it finds the second occurrence of "iss" because it is able to look  set to 4, it finds the second occurrence of "iss" because it is able to look
1766  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.
1767  .P  .P
1768    Finding all the matches in a subject is tricky when the pattern can match an
1769    empty string. It is possible to emulate Perl's /g behaviour by first trying the
1770    match again at the same offset, with the PCRE_NOTEMPTY_ATSTART and
1771    PCRE_ANCHORED options, and then if that fails, advancing the starting offset
1772    and trying an ordinary match again. There is some code that demonstrates how to
1773    do this in the
1774    .\" HREF
1775    \fBpcredemo\fP
1776    .\"
1777    sample program. In the most general case, you have to check to see if the
1778    newline convention recognizes CRLF as a newline, and if so, and the current
1779    character is CR followed by LF, advance the starting offset by two characters
1780    instead of one.
1781    .P
1782  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
1783  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
1784  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.
1785  .  .
1786    .
1787  .SS "How \fBpcre_exec()\fP returns captured substrings"  .SS "How \fBpcre_exec()\fP returns captured substrings"
1788  .rs  .rs
1789  .sp  .sp
# Line 1577  string that it matched that is returned. Line 1827  string that it matched that is returned.
1827  .P  .P
1828  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
1829  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
1830  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
1831  \fBpcre_exec()\fP may be called with \fIovector\fP passed as NULL and  substrings are of interest, \fBpcre_exec()\fP may be called with \fIovector\fP
1832  \fIovecsize\fP as zero. However, if the pattern contains back references and  passed as NULL and \fIovecsize\fP as zero. However, if the pattern contains
1833  the \fIovector\fP is not big enough to remember the related substrings, PCRE  back references and the \fIovector\fP is not big enough to remember the related
1834  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
1835  advisable to supply an \fIovector\fP.  is usually advisable to supply an \fIovector\fP of reasonable size.
1836    .P
1837    There are some cases where zero is returned (indicating vector overflow) when
1838    in fact the vector is exactly the right size for the final match. For example,
1839    consider the pattern
1840    .sp
1841      (a)(?:(b)c|bd)
1842    .sp
1843    If a vector of 6 elements (allowing for only 1 captured substring) is given
1844    with subject string "abd", \fBpcre_exec()\fP will try to set the second
1845    captured string, thereby recording a vector overflow, before failing to match
1846    "c" and backing up to try the second alternative. The zero return, however,
1847    does correctly indicate that the maximum number of slots (namely 2) have been
1848    filled. In similar cases where there is temporary overflow, but the final
1849    number of used slots is actually less than the maximum, a non-zero value is
1850    returned.
1851  .P  .P
1852  The \fBpcre_fullinfo()\fP function can be used to find out how many capturing  The \fBpcre_fullinfo()\fP function can be used to find out how many capturing
1853  subpatterns there are in a compiled pattern. The smallest size for  subpatterns there are in a compiled pattern. The smallest size for
# Line 1600  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    \fBNote\fP: Elements in the first two-thirds of \fIovector\fP that do not
1872    correspond to capturing parentheses in the pattern are never changed. That is,
1873    if a pattern contains \fIn\fP capturing parentheses, no more than
1874    \fIovector[0]\fP to \fIovector[2n+1]\fP are set by \fBpcre_exec()\fP. The other
1875    elements (in the first two-thirds) retain whatever values they previously had.
1876  .P  .P
1877  Some convenience functions are provided for extracting the captured substrings  Some convenience functions are provided for extracting the captured substrings
1878  as separate strings. These are described below.  as separate strings. These are described below.
1879  .  .
1880    .
1881  .\" HTML <a name="errorlist"></a>  .\" HTML <a name="errorlist"></a>
1882  .SS "Error return values from \fBpcre_exec()\fP"  .SS "Error return values from \fBpcre_exec()\fP"
1883  .rs  .rs
# Line 1676  documentation for details. Line 1947  documentation for details.
1947  .sp  .sp
1948    PCRE_ERROR_BADUTF8        (-10)    PCRE_ERROR_BADUTF8        (-10)
1949  .sp  .sp
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    (\fIovecsize\fP) 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    .\" HTML <a href="#badutf8reasons">
1956    .\" </a>
1957    following section.
1958    .\"
1959    For backward compatibility, if PCRE_PARTIAL_HARD is set and the problem is a
1960    truncated UTF-8 character at the end of the subject (reason codes 1 to 5),
1961    PCRE_ERROR_SHORTUTF8 is returned instead of PCRE_ERROR_BADUTF8.
1962  .sp  .sp
1963    PCRE_ERROR_BADUTF8_OFFSET (-11)    PCRE_ERROR_BADUTF8_OFFSET (-11)
1964  .sp  .sp
1965  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
1966  of \fIstartoffset\fP 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
1967    \fIstartoffset\fP did not point to the beginning of a UTF-8 character or the
1968    end of the subject.
1969  .sp  .sp
1970    PCRE_ERROR_PARTIAL        (-12)    PCRE_ERROR_PARTIAL        (-12)
1971  .sp  .sp
# Line 1716  description above. Line 2000  description above.
2000    PCRE_ERROR_BADNEWLINE     (-23)    PCRE_ERROR_BADNEWLINE     (-23)
2001  .sp  .sp
2002  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
2003    .sp
2004      PCRE_ERROR_BADOFFSET      (-24)
2005    .sp
2006    The value of \fIstartoffset\fP was negative or greater than the length of the
2007    subject, that is, the value in \fIlength\fP.
2008    .sp
2009      PCRE_ERROR_SHORTUTF8      (-25)
2010    .sp
2011    This error is returned instead of PCRE_ERROR_BADUTF8 when the subject string
2012    ends with a truncated UTF-8 character and the PCRE_PARTIAL_HARD option is set.
2013    Information about the failure is returned as for PCRE_ERROR_BADUTF8. It is in
2014    fact sufficient to detect this case, but this special error code for
2015    PCRE_PARTIAL_HARD precedes the implementation of returned information; it is
2016    retained for backwards compatibility.
2017    .sp
2018      PCRE_ERROR_RECURSELOOP    (-26)
2019    .sp
2020    This error is returned when \fBpcre_exec()\fP detects a recursion loop within
2021    the pattern. Specifically, it means that either the whole pattern or a
2022    subpattern has been called recursively for the second time at the same position
2023    in the subject string. Some simple patterns that might do this are detected and
2024    faulted at compile time, but more complicated cases, in particular mutual
2025    recursions between two different subpatterns, cannot be detected until run
2026    time.
2027    .sp
2028      PCRE_ERROR_JIT_STACKLIMIT (-27)
2029    .sp
2030    This error is returned when a pattern that was successfully studied using the
2031    PCRE_STUDY_JIT_COMPILE option is being matched, but the memory available for
2032    the just-in-time processing stack is not large enough. See the
2033    .\" HREF
2034    \fBpcrejit\fP
2035    .\"
2036    documentation for more details.
2037  .P  .P
2038  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
2039  .  .
2040  .  .
2041    .\" HTML <a name="badutf8reasons"></a>
2042    .SS "Reason codes for invalid UTF-8 strings"
2043    .rs
2044    .sp
2045    When \fBpcre_exec()\fP returns either PCRE_ERROR_BADUTF8 or
2046    PCRE_ERROR_SHORTUTF8, and the size of the output vector (\fIovecsize\fP) is at
2047    least 2, the offset of the start of the invalid UTF-8 character is placed in
2048    the first output vector element (\fIovector[0]\fP) and a reason code is placed
2049    in the second element (\fIovector[1]\fP). The reason codes are given names in
2050    the \fBpcre.h\fP header file:
2051    .sp
2052      PCRE_UTF8_ERR1
2053      PCRE_UTF8_ERR2
2054      PCRE_UTF8_ERR3
2055      PCRE_UTF8_ERR4
2056      PCRE_UTF8_ERR5
2057    .sp
2058    The string ends with a truncated UTF-8 character; the code specifies how many
2059    bytes are missing (1 to 5). Although RFC 3629 restricts UTF-8 characters to be
2060    no longer than 4 bytes, the encoding scheme (originally defined by RFC 2279)
2061    allows for up to 6 bytes, and this is checked first; hence the possibility of
2062    4 or 5 missing bytes.
2063    .sp
2064      PCRE_UTF8_ERR6
2065      PCRE_UTF8_ERR7
2066      PCRE_UTF8_ERR8
2067      PCRE_UTF8_ERR9
2068      PCRE_UTF8_ERR10
2069    .sp
2070    The two most significant bits of the 2nd, 3rd, 4th, 5th, or 6th byte of the
2071    character do not have the binary value 0b10 (that is, either the most
2072    significant bit is 0, or the next bit is 1).
2073    .sp
2074      PCRE_UTF8_ERR11
2075      PCRE_UTF8_ERR12
2076    .sp
2077    A character that is valid by the RFC 2279 rules is either 5 or 6 bytes long;
2078    these code points are excluded by RFC 3629.
2079    .sp
2080      PCRE_UTF8_ERR13
2081    .sp
2082    A 4-byte character has a value greater than 0x10fff; these code points are
2083    excluded by RFC 3629.
2084    .sp
2085      PCRE_UTF8_ERR14
2086    .sp
2087    A 3-byte character has a value in the range 0xd800 to 0xdfff; this range of
2088    code points are reserved by RFC 3629 for use with UTF-16, and so are excluded
2089    from UTF-8.
2090    .sp
2091      PCRE_UTF8_ERR15
2092      PCRE_UTF8_ERR16
2093      PCRE_UTF8_ERR17
2094      PCRE_UTF8_ERR18
2095      PCRE_UTF8_ERR19
2096    .sp
2097    A 2-, 3-, 4-, 5-, or 6-byte character is "overlong", that is, it codes for a
2098    value that can be represented by fewer bytes, which is invalid. For example,
2099    the two bytes 0xc0, 0xae give the value 0x2e, whose correct coding uses just
2100    one byte.
2101    .sp
2102      PCRE_UTF8_ERR20
2103    .sp
2104    The two most significant bits of the first byte of a character have the binary
2105    value 0b10 (that is, the most significant bit is 1 and the second is 0). Such a
2106    byte can only validly occur as the second or subsequent byte of a multi-byte
2107    character.
2108    .sp
2109      PCRE_UTF8_ERR21
2110    .sp
2111    The first byte of a character has the value 0xfe or 0xff. These values can
2112    never occur in a valid UTF-8 string.
2113    .
2114    .
2115  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
2116  .rs  .rs
2117  .sp  .sp
# Line 1882  names are not included in the compiled c Line 2274  names are not included in the compiled c
2274  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
2275  same number causes an error at compile time.  same number causes an error at compile time.
2276  .  .
2277    .
2278  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
2279  .rs  .rs
2280  .sp  .sp
# Line 1915  fourth are pointers to variables which a Line 2308  fourth are pointers to variables which a
2308  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
2309  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
2310  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
2311  described above in the section entitled \fIInformation about a pattern\fP.  described above in the section entitled \fIInformation about a pattern\fP
2312    .\" HTML <a href="#infoaboutpattern">
2313    .\" </a>
2314    above.
2315    .\"
2316  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
2317  numbers, and hence the captured data, if any.  numbers, and hence the captured data, if any.
2318  .  .
# Line 2018  is converted into PCRE_ERROR_PARTIAL if Line 2415  is converted into PCRE_ERROR_PARTIAL if
2415  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
2416  possibility. The portion of the string that was inspected when the longest  possibility. The portion of the string that was inspected when the longest
2417  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.
2418    There is a more detailed discussion of partial and multi-segment matching, with
2419    examples, in the
2420    .\" HREF
2421    \fBpcrepartial\fP
2422    .\"
2423    documentation.
2424  .sp  .sp
2425    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
2426  .sp  .sp
# Line 2039  match. There is more discussion of this Line 2442  match. There is more discussion of this
2442  .\"  .\"
2443  documentation.  documentation.
2444  .  .
2445    .
2446  .SS "Successful returns from \fBpcre_dfa_exec()\fP"  .SS "Successful returns from \fBpcre_dfa_exec()\fP"
2447  .rs  .rs
2448  .sp  .sp
# Line 2070  returns data, even though the meaning of Line 2474  returns data, even though the meaning of
2474  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
2475  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
2476  \fIovector\fP, the yield of the function is zero, and the vector is filled with  \fIovector\fP, the yield of the function is zero, and the vector is filled with
2477  the longest matches.  the longest matches. Unlike \fBpcre_exec()\fP, \fBpcre_dfa_exec()\fP can use
2478    the entire \fIovector\fP for returning matched strings.
2479    .
2480  .  .
2481  .SS "Error returns from \fBpcre_dfa_exec()\fP"  .SS "Error returns from \fBpcre_dfa_exec()\fP"
2482  .rs  .rs
# Line 2099  group. These are not supported. Line 2505  group. These are not supported.
2505    PCRE_ERROR_DFA_UMLIMIT    (-18)    PCRE_ERROR_DFA_UMLIMIT    (-18)
2506  .sp  .sp
2507  This return is given if \fBpcre_dfa_exec()\fP is called with an \fIextra\fP  This return is given if \fBpcre_dfa_exec()\fP is called with an \fIextra\fP
2508  block that contains a setting of the \fImatch_limit\fP field. This is not  block that contains a setting of the \fImatch_limit\fP or
2509  supported (it is meaningless).  \fImatch_limit_recursion\fP fields. This is not supported (these fields are
2510    meaningless for DFA matching).
2511  .sp  .sp
2512    PCRE_ERROR_DFA_WSSIZE     (-19)    PCRE_ERROR_DFA_WSSIZE     (-19)
2513  .sp  .sp
# Line 2137  Cambridge CB2 3QH, England. Line 2544  Cambridge CB2 3QH, England.
2544  .rs  .rs
2545  .sp  .sp
2546  .nf  .nf
2547  Last updated: 15 June 2010  Last updated: 14 November 2011
2548  Copyright (c) 1997-2010 University of Cambridge.  Copyright (c) 1997-2011 University of Cambridge.
2549  .fi  .fi

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