/[pcre]/code/trunk/doc/pcreapi.3
ViewVC logotype

Diff of /code/trunk/doc/pcreapi.3

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 243 by ph10, Thu Sep 13 09:28:14 2007 UTC revision 686 by ph10, Tue Sep 6 16:06:36 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 132  an application that uses PCRE. The heade Line 151  an application that uses PCRE. The heade
151  and PCRE_MINOR to contain the major and minor release numbers for the library.  and PCRE_MINOR to contain the major and minor release numbers for the library.
152  Applications can use these to include support for different releases of PCRE.  Applications can use these to include support for different releases of PCRE.
153  .P  .P
154    In a Windows environment, if you want to statically link an application program
155    against a non-dll \fBpcre.a\fP file, you must define PCRE_STATIC before
156    including \fBpcre.h\fP or \fBpcrecpp.h\fP, because otherwise the
157    \fBpcre_malloc()\fP and \fBpcre_free()\fP exported functions will be declared
158    \fB__declspec(dllimport)\fP, with unwanted results.
159    .P
160  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,
161  and \fBpcre_exec()\fP are used for compiling and matching regular expressions  and \fBpcre_exec()\fP are used for compiling and matching regular expressions
162  in a Perl-compatible manner. A sample program that demonstrates the simplest  in a Perl-compatible manner. A sample program that demonstrates the simplest
163  way of using them is provided in the file called \fIpcredemo.c\fP in the source  way of using them is provided in the file called \fIpcredemo.c\fP in the PCRE
164  distribution. The  source distribution. A listing of this program is given in the
165    .\" HREF
166    \fBpcredemo\fP
167    .\"
168    documentation, and the
169  .\" HREF  .\" HREF
170  \fBpcresample\fP  \fBpcresample\fP
171  .\"  .\"
172  documentation describes how to run it.  documentation describes how to compile and run it.
173    .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  .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
190  point in the subject), and scans the subject just once. However, this algorithm  point in the subject), and scans the subject just once (unless there are
191  does not return captured substrings. A description of the two matching  lookbehind assertions). However, this algorithm does not return captured
192  algorithms and their advantages and disadvantages is given in the  substrings. A description of the two matching algorithms and their advantages
193    and disadvantages is given in the
194  .\" HREF  .\" HREF
195  \fBpcrematching\fP  \fBpcrematching\fP
196  .\"  .\"
# Line 271  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 313  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
374  that is recognized as meaning "newline". The four values that are supported  that is recognized as meaning "newline". The four values that are supported
375  are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF, and -1 for ANY. The  are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF, and -1 for ANY.
376  default should normally be the standard sequence for your operating system.  Though they are derived from ASCII, the same values are returned in EBCDIC
377    environments. The default should normally correspond to the standard sequence
378    for your operating system.
379  .sp  .sp
380    PCRE_CONFIG_BSR    PCRE_CONFIG_BSR
381  .sp  .sp
# Line 347  documentation. Line 404  documentation.
404  .sp  .sp
405    PCRE_CONFIG_MATCH_LIMIT    PCRE_CONFIG_MATCH_LIMIT
406  .sp  .sp
407  The output is an integer that gives the default limit for the number of  The output is a long integer that gives the default limit for the number of
408  internal matching function calls in a \fBpcre_exec()\fP execution. Further  internal matching function calls in a \fBpcre_exec()\fP execution. Further
409  details are given with \fBpcre_exec()\fP below.  details are given with \fBpcre_exec()\fP below.
410  .sp  .sp
411    PCRE_CONFIG_MATCH_LIMIT_RECURSION    PCRE_CONFIG_MATCH_LIMIT_RECURSION
412  .sp  .sp
413  The output is an integer that gives the default limit for the depth of  The output is a long integer that gives the default limit for the depth of
414  recursion when calling the internal matching function in a \fBpcre_exec()\fP  recursion when calling the internal matching function in a \fBpcre_exec()\fP
415  execution. Further details are given with \fBpcre_exec()\fP below.  execution. Further details are given with \fBpcre_exec()\fP below.
416  .sp  .sp
# Line 388  avoiding the use of the stack. Line 445  avoiding the use of the stack.
445  Either of the functions \fBpcre_compile()\fP or \fBpcre_compile2()\fP can be  Either of the functions \fBpcre_compile()\fP or \fBpcre_compile2()\fP can be
446  called to compile a pattern into an internal form. The only difference between  called to compile a pattern into an internal form. The only difference between
447  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,
448  \fIerrorcodeptr\fP, via which a numerical error code can be returned.  \fIerrorcodeptr\fP, via which a numerical error code can be returned. To avoid
449    too much repetition, we refer just to \fBpcre_compile()\fP below, but the
450    information applies equally to \fBpcre_compile2()\fP.
451  .P  .P
452  The pattern is a C string terminated by a binary zero, and is passed in the  The pattern is a C string terminated by a binary zero, and is passed in the
453  \fIpattern\fP argument. A pointer to a single block of memory that is obtained  \fIpattern\fP argument. A pointer to a single block of memory that is obtained
# Line 404  argument, which is an address (see below Line 463  argument, which is an address (see below
463  .P  .P
464  The \fIoptions\fP argument contains various bit settings that affect the  The \fIoptions\fP argument contains various bit settings that affect the
465  compilation. It should be zero if no options are required. The available  compilation. It should be zero if no options are required. The available
466  options are described below. Some of them, in particular, those that are  options are described below. Some of them (in particular, those that are
467  compatible with Perl, can also be set and unset from within the pattern (see  compatible with Perl, but some others as well) can also be set and unset from
468  the detailed description in the  within the pattern (see the detailed description in the
469  .\" HREF  .\" HREF
470  \fBpcrepattern\fP  \fBpcrepattern\fP
471  .\"  .\"
472  documentation). For these options, the contents of the \fIoptions\fP argument  documentation). For those options that can be different in different parts of
473  specifies their initial settings at the start of compilation and execution. The  the pattern, the contents of the \fIoptions\fP argument specifies their
474  PCRE_ANCHORED and PCRE_NEWLINE_\fIxxx\fP options can be set at the time of  settings at the start of compilation and execution. The PCRE_ANCHORED,
475  matching as well as at compile time.  PCRE_BSR_\fIxxx\fP, PCRE_NEWLINE_\fIxxx\fP, PCRE_NO_UTF8_CHECK, and
476    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 offset from the start of the pattern to the character  not try to free it. Normally, the offset from the start of the pattern to the
484  where the error was discovered is placed in the variable pointed to by  byte that was being processed when the error was discovered is placed in the
485  \fIerroffset\fP, which must not be NULL. If it is, an immediate error is given.  variable pointed to by \fIerroffset\fP, which must not be NULL (if it is, an
486    immediate error is given). However, for an invalid UTF-8 string, the offset is
487    that of the first byte of the failing character. Also, some errors are not
488    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 500  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 527  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 540  set, any backslash in a pattern that is Line 620  set, any backslash in a pattern that is
620  special meaning causes an error, thus reserving these combinations for future  special meaning causes an error, thus reserving these combinations for future
621  expansion. By default, as in Perl, a backslash followed by a letter with no  expansion. By default, as in Perl, a backslash followed by a letter with no
622  special meaning is treated as a literal. (Perl can, however, be persuaded to  special meaning is treated as a literal. (Perl can, however, be persuaded to
623  give a warning for this.) There are at present no other features controlled by  give an error for this, by running it with the -w option.) There are at present
624  this option. It can also be set by a (?X) option setting within a pattern.  no other features controlled by this option. It can also be set by a (?X)
625    option setting within a pattern.
626  .sp  .sp
627    PCRE_FIRSTLINE    PCRE_FIRSTLINE
628  .sp  .sp
# Line 549  If this option is set, an unanchored pat Line 630  If this option is set, an unanchored pat
630  the first newline in the subject string, though the matched text may continue  the first newline in the subject string, though the matched text may continue
631  over the newline.  over the newline.
632  .sp  .sp
633      PCRE_JAVASCRIPT_COMPAT
634    .sp
635    If this option is set, PCRE's behaviour is changed in some ways so that it is
636    compatible with JavaScript rather than Perl. The changes are as follows:
637    .P
638    (1) A lone closing square bracket in a pattern causes a compile-time error,
639    because this is illegal in JavaScript (by default it is treated as a data
640    character). Thus, the pattern AB]CD becomes illegal when this option is set.
641    .P
642    (2) At run time, a back reference to an unset subpattern group matches an empty
643    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
645    an "a" in the subject), whereas it fails by default, for Perl compatibility.
646    .sp
647    PCRE_MULTILINE    PCRE_MULTILINE
648  .sp  .sp
649  By default, PCRE treats the subject string as consisting of a single line of  By default, PCRE treats the subject string as consisting of a single line of
# Line 590  option, the combination may or may not b Line 685  option, the combination may or may not b
685  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
686  other combinations may yield unused numbers and cause an error.  other combinations may yield unused numbers and cause an error.
687  .P  .P
688  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
689  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,
690  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
691  line break sequence. In other circumstances, line break sequences are treated  indicates a comment that lasts until after the next line break sequence. In
692  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
693  as whitespace characters and are therefore ignored.  data.
694  .P  .P
695  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
696  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 608  were followed by ?: but named parenthese Line 703  were followed by ?: but named parenthese
703  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
704  in Perl.  in Perl.
705  .sp  .sp
706      NO_START_OPTIMIZE
707    .sp
708    This is an option that acts at matching time; that is, it is really an option
709    for \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. If it is set at compile time,
710    it is remembered with the compiled pattern and assumed at matching time. For
711    details see the discussion of PCRE_NO_START_OPTIMIZE
712    .\" HTML <a href="#execoptions">
713    .\" </a>
714    below.
715    .\"
716    .sp
717      PCRE_UCP
718    .sp
719    This option changes the way PCRE processes \eB, \eb, \eD, \ed, \eS, \es, \eW,
720    \ew, and some of the POSIX character classes. By default, only ASCII characters
721    are recognized, but if PCRE_UCP is set, Unicode properties are used instead to
722    classify characters. More details are given in the section on
723    .\" HTML <a href="pcre.html#genericchartypes">
724    .\" </a>
725    generic character types
726    .\"
727    in the
728    .\" HREF
729    \fBpcrepattern\fP
730    .\"
731    page. If you set PCRE_UCP, matching one of the items it affects takes much
732    longer. The option is available only if PCRE has been compiled with Unicode
733    property support.
734    .sp
735    PCRE_UNGREEDY    PCRE_UNGREEDY
736  .sp  .sp
737  This option inverts the "greediness" of the quantifiers so that they are not  This option inverts the "greediness" of the quantifiers so that they are not
# Line 621  of UTF-8 characters instead of single-by Line 745  of UTF-8 characters instead of single-by
745  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
746  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
747  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  
748  .\" HREF  .\" HREF
749  \fBpcre\fP  \fBpcreunicode\fP
750  .\"  .\"
751  page.  page.
752  .sp  .sp
# Line 672  out of use. To avoid confusion, they hav Line 791  out of use. To avoid confusion, they hav
791     9  nothing to repeat     9  nothing to repeat
792    10  [this code is not in use]    10  [this code is not in use]
793    11  internal error: unexpected repeat    11  internal error: unexpected repeat
794    12  unrecognized character after (?    12  unrecognized character after (? or (?-
795    13  POSIX named classes are supported only within a class    13  POSIX named classes are supported only within a class
796    14  missing )    14  missing )
797    15  reference to non-existent subpattern    15  reference to non-existent subpattern
# Line 680  out of use. To avoid confusion, they hav Line 799  out of use. To avoid confusion, they hav
799    17  unknown option bit(s) set    17  unknown option bit(s) set
800    18  missing ) after comment    18  missing ) after comment
801    19  [this code is not in use]    19  [this code is not in use]
802    20  regular expression too large    20  regular expression is too large
803    21  failed to get memory    21  failed to get memory
804    22  unmatched parentheses    22  unmatched parentheses
805    23  internal error: code overflow    23  internal error: code overflow
# Line 697  out of use. To avoid confusion, they hav Line 816  out of use. To avoid confusion, they hav
816    34  character value in \ex{...} sequence is too large    34  character value in \ex{...} sequence is too large
817    35  invalid condition (?(0)    35  invalid condition (?(0)
818    36  \eC not allowed in lookbehind assertion    36  \eC not allowed in lookbehind assertion
819    37  PCRE does not support \eL, \el, \eN, \eU, or \eu    37  PCRE does not support \eL, \el, \eN{name}, \eU, or \eu
820    38  number after (?C is > 255    38  number after (?C is > 255
821    39  closing ) for (?C expected    39  closing ) for (?C expected
822    40  recursive call could loop indefinitely    40  recursive call could loop indefinitely
# Line 709  out of use. To avoid confusion, they hav Line 828  out of use. To avoid confusion, they hav
828    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
829    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
830    48  subpattern name is too long (maximum 32 characters)    48  subpattern name is too long (maximum 32 characters)
831    49  too many named subpatterns (maximum 10,000)    49  too many named subpatterns (maximum 10000)
832    50  [this code is not in use]    50  [this code is not in use]
833    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 (not in UTF-8 mode)
834    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
835    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern
836            not found
837    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
838    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
839    56  inconsistent NEWLINE options    56  inconsistent NEWLINE options
840    57  \eg is not followed by a braced name or an optionally braced    57  \eg is not followed by a braced, angle-bracketed, or quoted
841          non-zero number          name/number or by a plain number
842    58  (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number    58  a numbered reference must not be zero
843      59  an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT)
844      60  (*VERB) not recognized
845      61  number is too big
846      62  subpattern name expected
847      63  digit expected after (?+
848      64  ] is an invalid data character in JavaScript compatibility mode
849      65  different names for subpatterns of the same number are
850            not allowed
851      66  (*MARK) must have an argument
852      67  this version of PCRE is not compiled with PCRE_UCP support
853      68  \ec must be followed by an ASCII character
854      69  \ek is not followed by a braced, angle-bracketed, or quoted name
855    .sp
856    The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
857    be used if the limits were changed when PCRE was built.
858  .  .
859  .  .
860    .\" HTML <a name="studyingapattern"></a>
861  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
862  .rs  .rs
863  .sp  .sp
# Line 738  help speed up matching, \fBpcre_study()\ Line 874  help speed up matching, \fBpcre_study()\
874  results of the study.  results of the study.
875  .P  .P
876  The returned value from \fBpcre_study()\fP can be passed directly to  The returned value from \fBpcre_study()\fP can be passed directly to
877  \fBpcre_exec()\fP. However, a \fBpcre_extra\fP block also contains other  \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. However, a \fBpcre_extra\fP block
878  fields that can be set by the caller before the block is passed; these are  also contains other fields that can be set by the caller before the block is
879  described  passed; these are described
880  .\" HTML <a href="#extradata">  .\" HTML <a href="#extradata">
881  .\" </a>  .\" </a>
882  below  below
883  .\"  .\"
884  in the section on matching a pattern.  in the section on matching a pattern.
885  .P  .P
886  If studying the pattern does not produce any additional information  If studying the pattern does not produce any useful information,
887  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program
888  wants to pass any of the other fields to \fBpcre_exec()\fP, it must set up its  wants to pass any of the other fields to \fBpcre_exec()\fP or
889  own \fBpcre_extra\fP block.  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.
890  .P  .P
891  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
892  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
893    compiler is available, the pattern is further compiled into machine code that
894    executes much faster than the \fBpcre_exec()\fP matching function. If
895    the just-in-time compiler is not available, this option is ignored. All other
896    bits in the \fIoptions\fP argument must be zero.
897    .P
898    JIT compilation is a heavyweight optimization. It can take some time for
899    patterns to be analyzed, and for one-off matches and simple patterns the
900    benefit of faster execution might be offset by a much slower study time.
901    Not all patterns can be optimized by the JIT compiler. For those that cannot be
902    handled, matching automatically falls back to the \fBpcre_exec()\fP
903    interpreter. For more details, see the
904    .\" HREF
905    \fBpcrejit\fP
906    .\"
907    documentation.
908  .P  .P
909  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
910  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 762  static string that is part of the librar Line 913  static string that is part of the librar
913  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
914  sure that it has run successfully.  sure that it has run successfully.
915  .P  .P
916  This is a typical call to \fBpcre_study\fP():  When you are finished with a pattern, you can free the memory used for the
917    study data by calling \fBpcre_free_study()\fP. This function was added to the
918    API for release 8.20. For earlier versions, the memory could be freed with
919    \fBpcre_free()\fP, just like the pattern itself. This will still work in cases
920    where PCRE_STUDY_JIT_COMPILE is not used, but it is advisable to change to the
921    new function when convenient.
922    .P
923    This is a typical way in which \fBpcre_study\fP() is used (except that in a
924    real application there should be tests for errors):
925  .sp  .sp
926    pcre_extra *pe;    int rc;
927    pe = pcre_study(    pcre *re;
928      pcre_extra *sd;
929      re = pcre_compile("pattern", 0, &error, &erroroffset, NULL);
930      sd = pcre_study(
931      re,             /* result of pcre_compile() */      re,             /* result of pcre_compile() */
932      0,              /* no options exist */      0,              /* no options */
933      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
934  .sp    rc = pcre_exec(   /* see below for details of pcre_exec() options */
935  At present, studying a pattern is useful only for non-anchored patterns that do      re, sd, "subject", 7, 0, 0, ovector, 30);
936  not have a single fixed starting character. A bitmap of possible starting    ...
937  bytes is created.    pcre_free_study(sd);
938      pcre_free(re);
939    .sp
940    Studying a pattern does two things: first, a lower bound for the length of
941    subject string that is needed to match the pattern is computed. This does not
942    mean that there are any strings of that length that match, but it does
943    guarantee that no shorter strings match. The value is used by
944    \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP to avoid wasting time by trying to
945    match strings that are shorter than the lower bound. You can find out the value
946    in a calling program via the \fBpcre_fullinfo()\fP function.
947    .P
948    Studying a pattern is also useful for non-anchored patterns that do not have a
949    single fixed starting character. A bitmap of possible starting bytes is
950    created. This speeds up finding a position in the subject at which to start
951    matching.
952    .P
953    These two optimizations apply to both \fBpcre_exec()\fP and
954    \fBpcre_dfa_exec()\fP. However, they are not used by \fBpcre_exec()\fP if
955    \fBpcre_study()\fP is called with the PCRE_STUDY_JIT_COMPILE option, and
956    just-in-time compiling is successful. The optimizations can be disabled by
957    setting the PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or
958    \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains
959    callouts or (*MARK) (which cannot be handled by the JIT compiler), and you want
960    to make use of these facilities in cases where matching fails. See the
961    discussion of PCRE_NO_START_OPTIMIZE
962    .\" HTML <a href="#execoptions">
963    .\" </a>
964    below.
965    .\"
966  .  .
967  .  .
968  .\" HTML <a name="localesupport"></a>  .\" HTML <a name="localesupport"></a>
# Line 782  bytes is created. Line 972  bytes is created.
972  PCRE handles caseless matching, and determines whether characters are letters,  PCRE handles caseless matching, and determines whether characters are letters,
973  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
974  value. When running in UTF-8 mode, this applies only to characters with codes  value. When running in UTF-8 mode, this applies only to characters with codes
975  less than 128. Higher-valued codes never match escapes such as \ew or \ed, but  less than 128. By default, higher-valued codes never match escapes such as \ew
976  can be tested with \ep if PCRE is built with Unicode character property  or \ed, but they can be tested with \ep if PCRE is built with Unicode character
977  support. The use of locales with Unicode is discouraged. If you are handling  property support. Alternatively, the PCRE_UCP option can be set at compile
978  characters with codes greater than 128, you should either use UTF-8 and  time; this causes \ew and friends to use Unicode property support instead of
979  Unicode, or use locales, but not try to mix the two.  built-in tables. The use of locales with Unicode is discouraged. If you are
980    handling characters with codes greater than 128, you should either use UTF-8
981    and Unicode, or use locales, but not try to mix the two.
982  .P  .P
983  PCRE contains an internal set of tables that are used when the final argument  PCRE contains an internal set of tables that are used when the final argument
984  of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.  of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.
# Line 831  one in which it was compiled. Passing ta Line 1023  one in which it was compiled. Passing ta
1023  below in the section on matching a pattern.  below in the section on matching a pattern.
1024  .  .
1025  .  .
1026    .\" HTML <a name="infoaboutpattern"></a>
1027  .SH "INFORMATION ABOUT A PATTERN"  .SH "INFORMATION ABOUT A PATTERN"
1028  .rs  .rs
1029  .sp  .sp
# Line 862  check against passing an arbitrary memor Line 1055  check against passing an arbitrary memor
1055    size_t length;    size_t length;
1056    rc = pcre_fullinfo(    rc = pcre_fullinfo(
1057      re,               /* result of pcre_compile() */      re,               /* result of pcre_compile() */
1058      pe,               /* result of pcre_study(), or NULL */      sd,               /* result of pcre_study(), or NULL */
1059      PCRE_INFO_SIZE,   /* what is required */      PCRE_INFO_SIZE,   /* what is required */
1060      &length);         /* where to put the data */      &length);         /* where to put the data */
1061  .sp  .sp
# Line 923  explicit match is either a literal CR or Line 1116  explicit match is either a literal CR or
1116  .sp  .sp
1117    PCRE_INFO_JCHANGED    PCRE_INFO_JCHANGED
1118  .sp  .sp
1119  Return 1 if the (?J) option setting is used in the pattern, otherwise 0. The  Return 1 if the (?J) or (?-J) option setting is used in the pattern, otherwise
1120  fourth argument should point to an \fBint\fP variable. The (?J) internal option  0. The fourth argument should point to an \fBint\fP variable. (?J) and
1121  setting changes the local PCRE_DUPNAMES option.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
1122    .sp
1123      PCRE_INFO_JIT
1124    .sp
1125    Return 1 if the pattern was studied with the PCRE_STUDY_JIT_COMPILE option, and
1126    just-in-time compiling was successful. The fourth argument should point to an
1127    \fBint\fP variable. A return value of 0 means that JIT support is not available
1128    in this version of PCRE, or that the pattern was not studied with the
1129    PCRE_STUDY_JIT_COMPILE option, or that the JIT compiler could not handle this
1130    particular pattern. See the
1131    .\" HREF
1132    \fBpcrejit\fP
1133    .\"
1134    documentation for details of what can and cannot be handled.
1135  .sp  .sp
1136    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
1137  .sp  .sp
# Line 937  follows something of variable length. Fo Line 1143  follows something of variable length. Fo
1143  /^a\ed+z\ed+/ the returned value is "z", but for /^a\edz\ed/ the returned value  /^a\ed+z\ed+/ the returned value is "z", but for /^a\edz\ed/ the returned value
1144  is -1.  is -1.
1145  .sp  .sp
1146      PCRE_INFO_MINLENGTH
1147    .sp
1148    If the pattern was studied and a minimum length for matching subject strings
1149    was computed, its value is returned. Otherwise the returned value is -1. The
1150    value is a number of characters, not bytes (this may be relevant in UTF-8
1151    mode). The fourth argument should point to an \fBint\fP variable. A
1152    non-negative value is a lower bound to the length of any matching string. There
1153    may not be any strings of that length that do actually match, but every string
1154    that does match is at least that long.
1155    .sp
1156    PCRE_INFO_NAMECOUNT    PCRE_INFO_NAMECOUNT
1157    PCRE_INFO_NAMEENTRYSIZE    PCRE_INFO_NAMEENTRYSIZE
1158    PCRE_INFO_NAMETABLE    PCRE_INFO_NAMETABLE
# Line 957  entry; both of these return an \fBint\fP Line 1173  entry; both of these return an \fBint\fP
1173  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first
1174  entry of the table (a pointer to \fBchar\fP). The first two bytes of each entry  entry of the table (a pointer to \fBchar\fP). The first two bytes of each entry
1175  are the number of the capturing parenthesis, most significant byte first. The  are the number of the capturing parenthesis, most significant byte first. The
1176  rest of the entry is the corresponding name, zero terminated. The names are in  rest of the entry is the corresponding name, zero terminated.
1177  alphabetical order. When PCRE_DUPNAMES is set, duplicate names are in order of  .P
1178  their parentheses numbers. For example, consider the following pattern (assume  The names are in alphabetical order. Duplicate names may appear if (?| is used
1179  PCRE_EXTENDED is set, so white space - including newlines - is ignored):  to create multiple groups with the same number, as described in the
1180    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1181    .\" </a>
1182    section on duplicate subpattern numbers
1183    .\"
1184    in the
1185    .\" HREF
1186    \fBpcrepattern\fP
1187    .\"
1188    page. Duplicate names for subpatterns with different numbers are permitted only
1189    if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the
1190    table in the order in which they were found in the pattern. In the absence of
1191    (?| this is the order of increasing number; when (?| is used this is not
1192    necessarily the case because later subpatterns may have lower numbers.
1193    .P
1194    As a simple example of the name/number table, consider the following pattern
1195    (assume PCRE_EXTENDED is set, so white space - including newlines - is
1196    ignored):
1197  .sp  .sp
1198  .\" JOIN  .\" JOIN
1199    (?<date> (?<year>(\ed\ed)?\ed\ed) -    (?<date> (?<year>(\ed\ed)?\ed\ed) -
# Line 981  different for each compiled pattern. Line 1214  different for each compiled pattern.
1214  .sp  .sp
1215    PCRE_INFO_OKPARTIAL    PCRE_INFO_OKPARTIAL
1216  .sp  .sp
1217  Return 1 if the pattern can be used for partial matching, otherwise 0. The  Return 1 if the pattern can be used for partial matching with
1218  fourth argument should point to an \fBint\fP variable. The  \fBpcre_exec()\fP, otherwise 0. The fourth argument should point to an
1219    \fBint\fP variable. From release 8.00, this always returns 1, because the
1220    restrictions that previously applied to partial matching have been lifted. The
1221  .\" HREF  .\" HREF
1222  \fBpcrepartial\fP  \fBpcrepartial\fP
1223  .\"  .\"
1224  documentation lists the restrictions that apply to patterns when partial  documentation gives details of partial matching.
 matching is used.  
1225  .sp  .sp
1226    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1227  .sp  .sp
# Line 1021  variable. Line 1255  variable.
1255  .sp  .sp
1256    PCRE_INFO_STUDYSIZE    PCRE_INFO_STUDYSIZE
1257  .sp  .sp
1258  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
1259  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,
1260  \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.
1261  created by \fBpcre_study()\fP. The fourth argument should point to a  The \fIstudy_data\fP field is set by \fBpcre_study()\fP to record information
1262  \fBsize_t\fP variable.  that will speed up matching (see the section entitled
1263    .\" HTML <a href="#studyingapattern">
1264    .\" </a>
1265    "Studying a pattern"
1266    .\"
1267    above). The format of the \fIstudy_data\fP block is private, but its length
1268    is made available via this option so that it can be saved and restored (see the
1269    .\" HREF
1270    \fBpcreprecompile\fP
1271    .\"
1272    documentation for details).
1273  .  .
1274  .  .
1275  .SH "OBSOLETE INFO FUNCTION"  .SH "OBSOLETE INFO FUNCTION"
# Line 1086  is different. (This seems a highly unlik Line 1330  is different. (This seems a highly unlik
1330  .P  .P
1331  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
1332  compiled pattern, which is passed in the \fIcode\fP argument. If the  compiled pattern, which is passed in the \fIcode\fP argument. If the
1333  pattern has been studied, the result of the study should be passed in the  pattern was studied, the result of the study should be passed in the
1334  \fIextra\fP argument. This function is the main matching facility of the  \fIextra\fP argument. This function is the main matching facility of the
1335  library, and it operates in a Perl-like manner. For specialist use there is  library, and it operates in a Perl-like manner. For specialist use there is
1336  also an alternative matching function, which is described  also an alternative matching function, which is described
# Line 1120  Here is an example of a simple call to \ Line 1364  Here is an example of a simple call to \
1364      ovector,        /* vector of integers for substring information */      ovector,        /* vector of integers for substring information */
1365      30);            /* number of elements (NOT size in bytes) */      30);            /* number of elements (NOT size in bytes) */
1366  .  .
1367    .
1368  .\" HTML <a name="extradata"></a>  .\" HTML <a name="extradata"></a>
1369  .SS "Extra data for \fBpcre_exec()\fR"  .SS "Extra data for \fBpcre_exec()\fR"
1370  .rs  .rs
# Line 1132  fields (not necessarily in this order): Line 1377  fields (not necessarily in this order):
1377  .sp  .sp
1378    unsigned long int \fIflags\fP;    unsigned long int \fIflags\fP;
1379    void *\fIstudy_data\fP;    void *\fIstudy_data\fP;
1380      void *\fIexecutable_jit\fP;
1381    unsigned long int \fImatch_limit\fP;    unsigned long int \fImatch_limit\fP;
1382    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1383    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1384    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1385      unsigned char **\fImark\fP;
1386  .sp  .sp
1387  The \fIflags\fP field is a bitmap that specifies which of the other fields  The \fIflags\fP field is a bitmap that specifies which of the other fields
1388  are set. The flag bits are:  are set. The flag bits are:
1389  .sp  .sp
1390    PCRE_EXTRA_STUDY_DATA    PCRE_EXTRA_STUDY_DATA
1391      PCRE_EXTRA_EXECUTABLE_JIT
1392    PCRE_EXTRA_MATCH_LIMIT    PCRE_EXTRA_MATCH_LIMIT
1393    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1394    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1395    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1396      PCRE_EXTRA_MARK
1397  .sp  .sp
1398  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
1399  \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
1400  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
1401  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
1402    other fields and their corresponding flag bits.
1403  .P  .P
1404  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
1405  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,
1406  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
1407  classic example is the use of nested unlimited repeats.  classic example is a pattern that uses nested unlimited repeats.
1408  .P  .P
1409  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly  Internally, \fBpcre_exec()\fP uses a function called \fBmatch()\fP, which it
1410  (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
1411  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
1412  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
1413  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
1414  string.  in the subject string.
1415    .P
1416    When \fBpcre_exec()\fP is called with a pattern that was successfully studied
1417    with the PCRE_STUDY_JIT_COMPILE option, the way that the matching is executed
1418    is entirely different. However, there is still the possibility of runaway
1419    matching that goes on for a very long time, and so the \fImatch_limit\fP value
1420    is also used in this case (but in a different way) to limit how long the
1421    matching can continue.
1422  .P  .P
1423  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
1424  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 1174  The \fImatch_limit_recursion\fP field is Line 1431  The \fImatch_limit_recursion\fP field is
1431  instead of limiting the total number of times that \fBmatch()\fP is called, it  instead of limiting the total number of times that \fBmatch()\fP is called, it
1432  limits the depth of recursion. The recursion depth is a smaller number than the  limits the depth of recursion. The recursion depth is a smaller number than the
1433  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.
1434  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.
1435  .P  .P
1436  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
1437  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
1438  amount of heap memory that can be used.  stack, the amount of heap memory that can be used. This limit is not relevant,
1439    and is ignored, if the pattern was successfully studied with
1440    PCRE_STUDY_JIT_COMPILE.
1441  .P  .P
1442  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
1443  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 1187  with a \fBpcre_extra\fP block in which \ Line 1446  with a \fBpcre_extra\fP block in which \
1446  PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the \fIflags\fP field. If the limit  PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the \fIflags\fP field. If the limit
1447  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.
1448  .P  .P
1449  The \fIpcre_callout\fP field is used in conjunction with the "callout" feature,  The \fIcallout_data\fP field is used in conjunction with the "callout" feature,
1450  which is described in the  and is described in the
1451  .\" HREF  .\" HREF
1452  \fBpcrecallout\fP  \fBpcrecallout\fP
1453  .\"  .\"
# Line 1207  called. See the Line 1466  called. See the
1466  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1467  .\"  .\"
1468  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1469    .P
1470    If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must
1471    be set to point to a \fBchar *\fP variable. If the pattern contains any
1472    backtracking control verbs such as (*MARK:NAME), and the execution ends up with
1473    a name to pass back, a pointer to the name string (zero terminated) is placed
1474    in the variable pointed to by the \fImark\fP field. The names are within the
1475    compiled pattern; if you wish to retain such a name you must copy it before
1476    freeing the memory of a compiled pattern. If there is no name to pass back, the
1477    variable pointed to by the \fImark\fP field set to NULL. For details of the
1478    backtracking control verbs, see the section entitled
1479    .\" HTML <a href="pcrepattern#backtrackcontrol">
1480    .\" </a>
1481    "Backtracking control"
1482    .\"
1483    in the
1484    .\" HREF
1485    \fBpcrepattern\fP
1486    .\"
1487    documentation.
1488    .
1489  .  .
1490  .\" HTML <a name="execoptions"></a>  .\" HTML <a name="execoptions"></a>
1491  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
# Line 1214  documentation for a discussion of saving Line 1493  documentation for a discussion of saving
1493  .sp  .sp
1494  The unused bits of the \fIoptions\fP argument for \fBpcre_exec()\fP must be  The unused bits of the \fIoptions\fP argument for \fBpcre_exec()\fP must be
1495  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,
1496  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1497    PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
1498    PCRE_PARTIAL_HARD.
1499    .P
1500    If the pattern was successfully studied with the PCRE_STUDY_JIT_COMPILE option,
1501    the only supported options for JIT execution are PCRE_NO_UTF8_CHECK,
1502    PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NOTEMPTY_ATSTART. Note in
1503    particular that partial matching is not supported. If an unsupported option is
1504    used, JIT execution is disabled and the normal interpretive code in
1505    \fBpcre_exec()\fP is run.
1506  .sp  .sp
1507    PCRE_ANCHORED    PCRE_ANCHORED
1508  .sp  .sp
# Line 1289  match the empty string, the entire match Line 1577  match the empty string, the entire match
1577  .sp  .sp
1578    a?b?    a?b?
1579  .sp  .sp
1580  is applied to a string not beginning with "a" or "b", it matches the empty  is applied to a string not beginning with "a" or "b", it matches an empty
1581  string at the start of the subject. With PCRE_NOTEMPTY set, this match is not  string at the start of the subject. With PCRE_NOTEMPTY set, this match is not
1582  valid, so PCRE searches further into the string for occurrences of "a" or "b".  valid, so PCRE searches further into the string for occurrences of "a" or "b".
1583  .P  .sp
1584  Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case    PCRE_NOTEMPTY_ATSTART
1585  of a pattern match of the empty string within its \fBsplit()\fP function, and  .sp
1586  when using the /g modifier. It is possible to emulate Perl's behaviour after  This is like PCRE_NOTEMPTY, except that an empty string match that is not at
1587  matching a null string by first trying the match again at the same offset with  the start of the subject is permitted. If the pattern is anchored, such a match
1588  PCRE_NOTEMPTY and PCRE_ANCHORED, and then if that fails by advancing the  can occur only if the pattern contains \eK.
1589  starting offset (see below) and trying an ordinary match again. There is some  .P
1590  code that demonstrates how to do this in the \fIpcredemo.c\fP sample program.  Perl has no direct equivalent of PCRE_NOTEMPTY or PCRE_NOTEMPTY_ATSTART, but it
1591    does make a special case of a pattern match of the empty string within its
1592    \fBsplit()\fP function, and when using the /g modifier. It is possible to
1593    emulate Perl's behaviour after matching a null string by first trying the match
1594    again at the same offset with PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED, and then
1595    if that fails, by advancing the starting offset (see below) and trying an
1596    ordinary match again. There is some code that demonstrates how to do this in
1597    the
1598    .\" HREF
1599    \fBpcredemo\fP
1600    .\"
1601    sample program. In the most general case, you have to check to see if the
1602    newline convention recognizes CRLF as a newline, and if so, and the current
1603    character is CR followed by LF, advance the starting offset by two characters
1604    instead of one.
1605    .sp
1606      PCRE_NO_START_OPTIMIZE
1607    .sp
1608    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1609    a match, in order to speed up the process. For example, if it is known that an
1610    unanchored match must start with a specific character, it searches the subject
1611    for that character, and fails immediately if it cannot find it, without
1612    actually running the main matching function. This means that a special item
1613    such as (*COMMIT) at the start of a pattern is not considered until after a
1614    suitable starting point for the match has been found. When callouts or (*MARK)
1615    items are in use, these "start-up" optimizations can cause them to be skipped
1616    if the pattern is never actually used. The start-up optimizations are in effect
1617    a pre-scan of the subject that takes place before the pattern is run.
1618    .P
1619    The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1620    causing performance to suffer, but ensuring that in cases where the result is
1621    "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
1622    are considered at every possible starting position in the subject string. If
1623    PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching
1624    time.
1625    .P
1626    Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
1627    Consider the pattern
1628    .sp
1629      (*COMMIT)ABC
1630    .sp
1631    When this is compiled, PCRE records the fact that a match must start with the
1632    character "A". Suppose the subject string is "DEFABC". The start-up
1633    optimization scans along the subject, finds "A" and runs the first match
1634    attempt from there. The (*COMMIT) item means that the pattern must match the
1635    current starting position, which in this case, it does. However, if the same
1636    match is run with PCRE_NO_START_OPTIMIZE set, the initial scan along the
1637    subject string does not happen. The first match attempt is run starting from
1638    "D" and when this fails, (*COMMIT) prevents any further matches being tried, so
1639    the overall result is "no match". If the pattern is studied, more start-up
1640    optimizations may be used. For example, a minimum length for the subject may be
1641    recorded. Consider the pattern
1642    .sp
1643      (*MARK:A)(X|Y)
1644    .sp
1645    The minimum length for a match is one character. If the subject is "ABC", there
1646    will be attempts to match "ABC", "BC", "C", and then finally an empty string.
1647    If the pattern is studied, the final attempt does not take place, because PCRE
1648    knows that the subject is too short, and so the (*MARK) is never encountered.
1649    In this case, studying the pattern does not affect the overall match result,
1650    which is still "no match", but it does affect the auxiliary information that is
1651    returned.
1652  .sp  .sp
1653    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1654  .sp  .sp
# Line 1317  in the main Line 1666  in the main
1666  \fBpcre\fP  \fBpcre\fP
1667  .\"  .\"
1668  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
1669  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
1670  PCRE_ERROR_BADUTF8_OFFSET is returned.  a truncated UTF-8 character at the end of the subject, PCRE_ERROR_SHORTUTF8. In
1671    both cases, information about the precise nature of the error may also be
1672    returned (see the descriptions of these errors in the section entitled \fIError
1673    return values from\fP \fBpcre_exec()\fP
1674    .\" HTML <a href="#errorlist">
1675    .\" </a>
1676    below).
1677    .\"
1678    If \fIstartoffset\fP contains a value that does not point to the start of a
1679    UTF-8 character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
1680    returned.
1681  .P  .P
1682  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
1683  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
1684  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
1685  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
1686  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
1687  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
1688  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
1689  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
1690  UTF-8 character, is undefined. Your program may crash.  undefined. Your program may crash.
1691  .sp  .sp
1692    PCRE_PARTIAL    PCRE_PARTIAL_HARD
1693  .sp    PCRE_PARTIAL_SOFT
1694  This option turns on the partial matching feature. If the subject string fails  .sp
1695  to match the pattern, but at some point during the matching process the end of  These options turn on the partial matching feature. For backwards
1696  the subject was reached (that is, the subject partially matches the pattern and  compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match
1697  the failure to match occurred only because there were not enough subject  occurs if the end of the subject string is reached successfully, but there are
1698  characters), \fBpcre_exec()\fP returns PCRE_ERROR_PARTIAL instead of  not enough subject characters to complete the match. If this happens when
1699  PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is used, there are restrictions on what  PCRE_PARTIAL_SOFT (but not PCRE_PARTIAL_HARD) is set, matching continues by
1700  may appear in the pattern. These are discussed in the  testing any remaining alternatives. Only if no complete match can be found is
1701    PCRE_ERROR_PARTIAL returned instead of PCRE_ERROR_NOMATCH. In other words,
1702    PCRE_PARTIAL_SOFT says that the caller is prepared to handle a partial match,
1703    but only if no complete match can be found.
1704    .P
1705    If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a
1706    partial match is found, \fBpcre_exec()\fP immediately returns
1707    PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,
1708    when PCRE_PARTIAL_HARD is set, a partial match is considered to be more
1709    important that an alternative complete match.
1710    .P
1711    In both cases, the portion of the string that was inspected when the partial
1712    match was found is set as the first matching string. There is a more detailed
1713    discussion of partial and multi-segment matching, with examples, in the
1714  .\" HREF  .\" HREF
1715  \fBpcrepartial\fP  \fBpcrepartial\fP
1716  .\"  .\"
1717  documentation.  documentation.
1718  .  .
1719    .
1720  .SS "The string to be matched by \fBpcre_exec()\fP"  .SS "The string to be matched by \fBpcre_exec()\fP"
1721  .rs  .rs
1722  .sp  .sp
1723  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
1724  \fIsubject\fP, a length in \fIlength\fP, and a starting byte offset in  \fIsubject\fP, a length (in bytes) in \fIlength\fP, and a starting byte offset
1725  \fIstartoffset\fP. In UTF-8 mode, the byte offset must point to the start of a  in \fIstartoffset\fP. If this is negative or greater than the length of the
1726  UTF-8 character. Unlike the pattern string, the subject may contain binary zero  subject, \fBpcre_exec()\fP returns PCRE_ERROR_BADOFFSET. When the starting
1727  bytes. When the starting offset is zero, the search for a match starts at the  offset is zero, the search for a match starts at the beginning of the subject,
1728  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
1729    point to the start of a UTF-8 character (or the end of the subject). Unlike the
1730    pattern string, the subject may contain binary zero bytes.
1731  .P  .P
1732  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
1733  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 1372  start of the subject, which is deemed to Line 1747  start of the subject, which is deemed to
1747  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
1748  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.
1749  .P  .P
1750    Finding all the matches in a subject is tricky when the pattern can match an
1751    empty string. It is possible to emulate Perl's /g behaviour by first trying the
1752    match again at the same offset, with the PCRE_NOTEMPTY_ATSTART and
1753    PCRE_ANCHORED options, and then if that fails, advancing the starting offset
1754    and trying an ordinary match again. There is some code that demonstrates how to
1755    do this in the
1756    .\" HREF
1757    \fBpcredemo\fP
1758    .\"
1759    sample program. In the most general case, you have to check to see if the
1760    newline convention recognizes CRLF as a newline, and if so, and the current
1761    character is CR followed by LF, advance the starting offset by two characters
1762    instead of one.
1763    .P
1764  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
1765  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
1766  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.
1767  .  .
1768    .
1769  .SS "How \fBpcre_exec()\fP returns captured substrings"  .SS "How \fBpcre_exec()\fP returns captured substrings"
1770  .rs  .rs
1771  .sp  .sp
# Line 1386  pattern. Following the usage in Jeffrey Line 1776  pattern. Following the usage in Jeffrey
1776  a fragment of a pattern that picks out a substring. PCRE supports several other  a fragment of a pattern that picks out a substring. PCRE supports several other
1777  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1778  .P  .P
1779  Captured substrings are returned to the caller via a vector of integer offsets  Captured substrings are returned to the caller via a vector of integers whose
1780  whose address is passed in \fIovector\fP. The number of elements in the vector  address is passed in \fIovector\fP. The number of elements in the vector is
1781  is passed in \fIovecsize\fP, which must be a non-negative number. \fBNote\fP:  passed in \fIovecsize\fP, which must be a non-negative number. \fBNote\fP: this
1782  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1783  .P  .P
1784  The first two-thirds of the vector is used to pass back captured substrings,  The first two-thirds of the vector is used to pass back captured substrings,
1785  each substring using a pair of integers. The remaining third of the vector is  each substring using a pair of integers. The remaining third of the vector is
1786  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1787  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1788  \fIovecsize\fP should always be a multiple of three. If it is not, it is  \fIovecsize\fP should always be a multiple of three. If it is not, it is
1789  rounded down.  rounded down.
1790  .P  .P
1791  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1792  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1793  continuing up to two-thirds of its length at the most. The first element of a  continuing up to two-thirds of its length at the most. The first element of
1794  pair is set to the offset of the first character in a substring, and the second  each pair is set to the byte offset of the first character in a substring, and
1795  is set to the offset of the first character after the end of a substring. The  the second is set to the byte offset of the first character after the end of a
1796  first pair, \fIovector[0]\fP and \fIovector[1]\fP, identify the portion of the  substring. \fBNote\fP: these values are always byte offsets, even in UTF-8
1797  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1798  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1799  is one more than the highest numbered pair that has been set. For example, if  The first pair of integers, \fIovector[0]\fP and \fIovector[1]\fP, identify the
1800  two substrings have been captured, the returned value is 3. If there are no  portion of the subject string matched by the entire pattern. The next pair is
1801  capturing subpatterns, the return value from a successful match is 1,  used for the first capturing subpattern, and so on. The value returned by
1802  indicating that just the first pair of offsets has been set.  \fBpcre_exec()\fP is one more than the highest numbered pair that has been set.
1803    For example, if two substrings have been captured, the returned value is 3. If
1804    there are no capturing subpatterns, the return value from a successful match is
1805    1, indicating that just the first pair of offsets has been set.
1806  .P  .P
1807  If a capturing subpattern is matched repeatedly, it is the last portion of the  If a capturing subpattern is matched repeatedly, it is the last portion of the
1808  string that it matched that is returned.  string that it matched that is returned.
1809  .P  .P
1810  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
1811  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
1812  returns a value of zero. In particular, if the substring offsets are not of  returns a value of zero. If neither the actual string matched not any captured
1813  interest, \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
1814  \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
1815  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
1816  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
1817  advisable to supply an \fIovector\fP.  is usually advisable to supply an \fIovector\fP of reasonable size.
1818    .P
1819    There are some cases where zero is returned (indicating vector overflow) when
1820    in fact the vector is exactly the right size for the final match. For example,
1821    consider the pattern
1822    .sp
1823      (a)(?:(b)c|bd)
1824    .sp
1825    If a vector of 6 elements (allowing for only 1 captured substring) is given
1826    with subject string "abd", \fBpcre_exec()\fP will try to set the second
1827    captured string, thereby recording a vector overflow, before failing to match
1828    "c" and backing up to try the second alternative. The zero return, however,
1829    does correctly indicate that the maximum number of slots (namely 2) have been
1830    filled. In similar cases where there is temporary overflow, but the final
1831    number of used slots is actually less than the maximum, a non-zero value is
1832    returned.
1833  .P  .P
1834  The \fBpcre_info()\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
1835  subpatterns there are in a compiled pattern. The smallest size for  subpatterns there are in a compiled pattern. The smallest size for
1836  \fIovector\fP that will allow for \fIn\fP captured substrings, in addition to  \fIovector\fP that will allow for \fIn\fP captured substrings, in addition to
1837  the offsets of the substring matched by the whole pattern, is (\fIn\fP+1)*3.  the offsets of the substring matched by the whole pattern, is (\fIn\fP+1)*3.
# Line 1439  Offset values that correspond to unused Line 1847  Offset values that correspond to unused
1847  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
1848  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
1849  return from the function is 2, because the highest used capturing subpattern  return from the function is 2, because the highest used capturing subpattern
1850  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
1851  capturing subpatterns if you wish (assuming the vector is large enough, of  (assuming the vector is large enough, of course) are set to -1.
1852  course).  .P
1853    \fBNote\fP: Elements in the first two-thirds of \fIovector\fP that do not
1854    correspond to capturing parentheses in the pattern are never changed. That is,
1855    if a pattern contains \fIn\fP capturing parentheses, no more than
1856    \fIovector[0]\fP to \fIovector[2n+1]\fP are set by \fBpcre_exec()\fP. The other
1857    elements (in the first two-thirds) retain whatever values they previously had.
1858  .P  .P
1859  Some convenience functions are provided for extracting the captured substrings  Some convenience functions are provided for extracting the captured substrings
1860  as separate strings. These are described below.  as separate strings. These are described below.
1861  .  .
1862    .
1863  .\" HTML <a name="errorlist"></a>  .\" HTML <a name="errorlist"></a>
1864  .SS "Error return values from \fBpcre_exec()\fP"  .SS "Error return values from \fBpcre_exec()\fP"
1865  .rs  .rs
# Line 1487  If a pattern contains back references, b Line 1901  If a pattern contains back references, b
1901  gets a block of memory at the start of matching to use for this purpose. If the  gets a block of memory at the start of matching to use for this purpose. If the
1902  call via \fBpcre_malloc()\fP fails, this error is given. The memory is  call via \fBpcre_malloc()\fP fails, this error is given. The memory is
1903  automatically freed at the end of matching.  automatically freed at the end of matching.
1904    .P
1905    This error is also given if \fBpcre_stack_malloc()\fP fails in
1906    \fBpcre_exec()\fP. This can happen only when PCRE has been compiled with
1907    \fB--disable-stack-for-recursion\fP.
1908  .sp  .sp
1909    PCRE_ERROR_NOSUBSTRING    (-7)    PCRE_ERROR_NOSUBSTRING    (-7)
1910  .sp  .sp
# Line 1511  documentation for details. Line 1929  documentation for details.
1929  .sp  .sp
1930    PCRE_ERROR_BADUTF8        (-10)    PCRE_ERROR_BADUTF8        (-10)
1931  .sp  .sp
1932  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,
1933    and the PCRE_NO_UTF8_CHECK option was not set. If the size of the output vector
1934    (\fIovecsize\fP) is at least 2, the byte offset to the start of the the invalid
1935    UTF-8 character is placed in the first element, and a reason code is placed in
1936    the second element. The reason codes are listed in the
1937    .\" HTML <a href="#badutf8reasons">
1938    .\" </a>
1939    following section.
1940    .\"
1941    For backward compatibility, if PCRE_PARTIAL_HARD is set and the problem is a
1942    truncated UTF-8 character at the end of the subject (reason codes 1 to 5),
1943    PCRE_ERROR_SHORTUTF8 is returned instead of PCRE_ERROR_BADUTF8.
1944  .sp  .sp
1945    PCRE_ERROR_BADUTF8_OFFSET (-11)    PCRE_ERROR_BADUTF8_OFFSET (-11)
1946  .sp  .sp
1947  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
1948  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
1949    \fIstartoffset\fP did not point to the beginning of a UTF-8 character or the
1950    end of the subject.
1951  .sp  .sp
1952    PCRE_ERROR_PARTIAL        (-12)    PCRE_ERROR_PARTIAL        (-12)
1953  .sp  .sp
# Line 1528  documentation for details of partial mat Line 1959  documentation for details of partial mat
1959  .sp  .sp
1960    PCRE_ERROR_BADPARTIAL     (-13)    PCRE_ERROR_BADPARTIAL     (-13)
1961  .sp  .sp
1962  The PCRE_PARTIAL option was used with a compiled pattern containing items that  This code is no longer in use. It was formerly returned when the PCRE_PARTIAL
1963  are not supported for partial matching. See the  option was used with a compiled pattern containing items that were not
1964  .\" HREF  supported for partial matching. From release 8.00 onwards, there are no
1965  \fBpcrepartial\fP  restrictions on partial matching.
 .\"  
 documentation for details of partial matching.  
1966  .sp  .sp
1967    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
1968  .sp  .sp
# Line 1553  description above. Line 1982  description above.
1982    PCRE_ERROR_BADNEWLINE     (-23)    PCRE_ERROR_BADNEWLINE     (-23)
1983  .sp  .sp
1984  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
1985    .sp
1986      PCRE_ERROR_BADOFFSET      (-24)
1987    .sp
1988    The value of \fIstartoffset\fP was negative or greater than the length of the
1989    subject, that is, the value in \fIlength\fP.
1990    .sp
1991      PCRE_ERROR_SHORTUTF8      (-25)
1992    .sp
1993    This error is returned instead of PCRE_ERROR_BADUTF8 when the subject string
1994    ends with a truncated UTF-8 character and the PCRE_PARTIAL_HARD option is set.
1995    Information about the failure is returned as for PCRE_ERROR_BADUTF8. It is in
1996    fact sufficient to detect this case, but this special error code for
1997    PCRE_PARTIAL_HARD precedes the implementation of returned information; it is
1998    retained for backwards compatibility.
1999    .sp
2000      PCRE_ERROR_RECURSELOOP    (-26)
2001    .sp
2002    This error is returned when \fBpcre_exec()\fP detects a recursion loop within
2003    the pattern. Specifically, it means that either the whole pattern or a
2004    subpattern has been called recursively for the second time at the same position
2005    in the subject string. Some simple patterns that might do this are detected and
2006    faulted at compile time, but more complicated cases, in particular mutual
2007    recursions between two different subpatterns, cannot be detected until run
2008    time.
2009    .sp
2010      PCRE_ERROR_JIT_STACKLIMIT (-27)
2011    .sp
2012    This error is returned when a pattern that was successfully studied using the
2013    PCRE_STUDY_JIT_COMPILE option is being matched, but the memory available for
2014    the just-in-time processing stack is not large enough. See the
2015    .\" HREF
2016    \fBpcrejit\fP
2017    .\"
2018    documentation for more details.
2019  .P  .P
2020  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.
2021  .  .
2022  .  .
2023    .\" HTML <a name="badutf8reasons"></a>
2024    .SS "Reason codes for invalid UTF-8 strings"
2025    .rs
2026    .sp
2027    When \fBpcre_exec()\fP returns either PCRE_ERROR_BADUTF8 or
2028    PCRE_ERROR_SHORTUTF8, and the size of the output vector (\fIovecsize\fP) is at
2029    least 2, the offset of the start of the invalid UTF-8 character is placed in
2030    the first output vector element (\fIovector[0]\fP) and a reason code is placed
2031    in the second element (\fIovector[1]\fP). The reason codes are given names in
2032    the \fBpcre.h\fP header file:
2033    .sp
2034      PCRE_UTF8_ERR1
2035      PCRE_UTF8_ERR2
2036      PCRE_UTF8_ERR3
2037      PCRE_UTF8_ERR4
2038      PCRE_UTF8_ERR5
2039    .sp
2040    The string ends with a truncated UTF-8 character; the code specifies how many
2041    bytes are missing (1 to 5). Although RFC 3629 restricts UTF-8 characters to be
2042    no longer than 4 bytes, the encoding scheme (originally defined by RFC 2279)
2043    allows for up to 6 bytes, and this is checked first; hence the possibility of
2044    4 or 5 missing bytes.
2045    .sp
2046      PCRE_UTF8_ERR6
2047      PCRE_UTF8_ERR7
2048      PCRE_UTF8_ERR8
2049      PCRE_UTF8_ERR9
2050      PCRE_UTF8_ERR10
2051    .sp
2052    The two most significant bits of the 2nd, 3rd, 4th, 5th, or 6th byte of the
2053    character do not have the binary value 0b10 (that is, either the most
2054    significant bit is 0, or the next bit is 1).
2055    .sp
2056      PCRE_UTF8_ERR11
2057      PCRE_UTF8_ERR12
2058    .sp
2059    A character that is valid by the RFC 2279 rules is either 5 or 6 bytes long;
2060    these code points are excluded by RFC 3629.
2061    .sp
2062      PCRE_UTF8_ERR13
2063    .sp
2064    A 4-byte character has a value greater than 0x10fff; these code points are
2065    excluded by RFC 3629.
2066    .sp
2067      PCRE_UTF8_ERR14
2068    .sp
2069    A 3-byte character has a value in the range 0xd800 to 0xdfff; this range of
2070    code points are reserved by RFC 3629 for use with UTF-16, and so are excluded
2071    from UTF-8.
2072    .sp
2073      PCRE_UTF8_ERR15
2074      PCRE_UTF8_ERR16
2075      PCRE_UTF8_ERR17
2076      PCRE_UTF8_ERR18
2077      PCRE_UTF8_ERR19
2078    .sp
2079    A 2-, 3-, 4-, 5-, or 6-byte character is "overlong", that is, it codes for a
2080    value that can be represented by fewer bytes, which is invalid. For example,
2081    the two bytes 0xc0, 0xae give the value 0x2e, whose correct coding uses just
2082    one byte.
2083    .sp
2084      PCRE_UTF8_ERR20
2085    .sp
2086    The two most significant bits of the first byte of a character have the binary
2087    value 0b10 (that is, the most significant bit is 1 and the second is 0). Such a
2088    byte can only validly occur as the second or subsequent byte of a multi-byte
2089    character.
2090    .sp
2091      PCRE_UTF8_ERR21
2092    .sp
2093    The first byte of a character has the value 0xfe or 0xff. These values can
2094    never occur in a valid UTF-8 string.
2095    .
2096    .
2097  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
2098  .rs  .rs
2099  .sp  .sp
# Line 1703  These functions call \fBpcre_get_stringn Line 2240  These functions call \fBpcre_get_stringn
2240  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
2241  appropriate. \fBNOTE:\fP If PCRE_DUPNAMES is set and there are duplicate names,  appropriate. \fBNOTE:\fP If PCRE_DUPNAMES is set and there are duplicate names,
2242  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
2243    .P
2244    \fBWarning:\fP If the pattern uses the (?| feature to set up multiple
2245    subpatterns with the same number, as described in the
2246    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
2247    .\" </a>
2248    section on duplicate subpattern numbers
2249    .\"
2250    in the
2251    .\" HREF
2252    \fBpcrepattern\fP
2253    .\"
2254    page, you cannot use names to distinguish the different subpatterns, because
2255    names are not included in the compiled code. The matching process uses only
2256    numbers. For this reason, the use of different names for subpatterns of the
2257    same number causes an error at compile time.
2258  .  .
2259  .  .
2260  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
# Line 1713  the behaviour may not be what you want ( Line 2265  the behaviour may not be what you want (
2265  .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);  .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
2266  .PP  .PP
2267  When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns  When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns
2268  are not required to be unique. Normally, patterns with duplicate names are such  are not required to be unique. (Duplicate names are always allowed for
2269  that in any one match, only one of the named subpatterns participates. An  subpatterns with the same number, created by using the (?| feature. Indeed, if
2270  example is shown in the  such subpatterns are named, they are required to use the same names.)
2271    .P
2272    Normally, patterns with duplicate names are such that in any one match, only
2273    one of the named subpatterns participates. An example is shown in the
2274  .\" HREF  .\" HREF
2275  \fBpcrepattern\fP  \fBpcrepattern\fP
2276  .\"  .\"
# Line 1735  fourth are pointers to variables which a Line 2290  fourth are pointers to variables which a
2290  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
2291  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
2292  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
2293  described above in the section entitled \fIInformation about a pattern\fP.  described above in the section entitled \fIInformation about a pattern\fP
2294    .\" HTML <a href="#infoaboutpattern">
2295    .\" </a>
2296    above.
2297    .\"
2298  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
2299  numbers, and hence the captured data, if any.  numbers, and hence the captured data, if any.
2300  .  .
# Line 1779  a compiled pattern, using a matching alg Line 2338  a compiled pattern, using a matching alg
2338  just once, and does not backtrack. This has different characteristics to the  just once, and does not backtrack. This has different characteristics to the
2339  normal algorithm, and is not compatible with Perl. Some of the features of PCRE  normal algorithm, and is not compatible with Perl. Some of the features of PCRE
2340  patterns are not supported. Nevertheless, there are times when this kind of  patterns are not supported. Nevertheless, there are times when this kind of
2341  matching can be useful. For a discussion of the two matching algorithms, see  matching can be useful. For a discussion of the two matching algorithms, and a
2342  the  list of features that \fBpcre_dfa_exec()\fP does not support, see the
2343  .\" HREF  .\" HREF
2344  \fBpcrematching\fP  \fBpcrematching\fP
2345  .\"  .\"
# Line 1819  Here is an example of a simple call to \ Line 2378  Here is an example of a simple call to \
2378  .sp  .sp
2379  The unused bits of the \fIoptions\fP argument for \fBpcre_dfa_exec()\fP must be  The unused bits of the \fIoptions\fP argument for \fBpcre_dfa_exec()\fP must be
2380  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,
2381  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
2382  PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last three of these are  PCRE_NO_UTF8_CHECK, PCRE_BSR_ANYCRLF, PCRE_BSR_UNICODE, PCRE_NO_START_OPTIMIZE,
2383  the same as for \fBpcre_exec()\fP, so their description is not repeated here.  PCRE_PARTIAL_HARD, PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART.
2384  .sp  All but the last four of these are exactly the same as for \fBpcre_exec()\fP,
2385    PCRE_PARTIAL  so their description is not repeated here.
2386  .sp  .sp
2387  This has the same general effect as it does for \fBpcre_exec()\fP, but the    PCRE_PARTIAL_HARD
2388  details are slightly different. When PCRE_PARTIAL is set for    PCRE_PARTIAL_SOFT
2389  \fBpcre_dfa_exec()\fP, the return code PCRE_ERROR_NOMATCH is converted into  .sp
2390  PCRE_ERROR_PARTIAL if the end of the subject is reached, there have been no  These have the same general effect as they do for \fBpcre_exec()\fP, but the
2391  complete matches, but there is still at least one matching possibility. The  details are slightly different. When PCRE_PARTIAL_HARD is set for
2392  portion of the string that provided the partial match is set as the first  \fBpcre_dfa_exec()\fP, it returns PCRE_ERROR_PARTIAL if the end of the subject
2393  matching string.  is reached and there is still at least one matching possibility that requires
2394    additional characters. This happens even if some complete matches have also
2395    been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
2396    is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached,
2397    there have been no complete matches, but there is still at least one matching
2398    possibility. The portion of the string that was inspected when the longest
2399    partial match was found is set as the first matching string in both cases.
2400    There is a more detailed discussion of partial and multi-segment matching, with
2401    examples, in the
2402    .\" HREF
2403    \fBpcrepartial\fP
2404    .\"
2405    documentation.
2406  .sp  .sp
2407    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
2408  .sp  .sp
# Line 1842  matching point in the subject string. Line 2413  matching point in the subject string.
2413  .sp  .sp
2414    PCRE_DFA_RESTART    PCRE_DFA_RESTART
2415  .sp  .sp
2416  When \fBpcre_dfa_exec()\fP is called with the PCRE_PARTIAL option, and returns  When \fBpcre_dfa_exec()\fP returns a partial match, it is possible to call it
2417  a partial match, it is possible to call it again, with additional subject  again, with additional subject characters, and have it continue with the same
2418  characters, and have it continue with the same match. The PCRE_DFA_RESTART  match. The PCRE_DFA_RESTART option requests this action; when it is set, the
2419  option requests this action; when it is set, the \fIworkspace\fP and  \fIworkspace\fP and \fIwscount\fP options must reference the same vector as
2420  \fIwscount\fP options must reference the same vector as before because data  before because data about the match so far is left in them after a partial
2421  about the match so far is left in them after a partial match. There is more  match. There is more discussion of this facility in the
 discussion of this facility in the  
2422  .\" HREF  .\" HREF
2423  \fBpcrepartial\fP  \fBpcrepartial\fP
2424  .\"  .\"
2425  documentation.  documentation.
2426  .  .
2427    .
2428  .SS "Successful returns from \fBpcre_dfa_exec()\fP"  .SS "Successful returns from \fBpcre_dfa_exec()\fP"
2429  .rs  .rs
2430  .sp  .sp
# Line 1885  returns data, even though the meaning of Line 2456  returns data, even though the meaning of
2456  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
2457  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
2458  \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
2459  the longest matches.  the longest matches. Unlike \fBpcre_exec()\fP, \fBpcre_dfa_exec()\fP can use
2460    the entire \fIovector\fP for returning matched strings.
2461    .
2462  .  .
2463  .SS "Error returns from \fBpcre_dfa_exec()\fP"  .SS "Error returns from \fBpcre_dfa_exec()\fP"
2464  .rs  .rs
# Line 1914  group. These are not supported. Line 2487  group. These are not supported.
2487    PCRE_ERROR_DFA_UMLIMIT    (-18)    PCRE_ERROR_DFA_UMLIMIT    (-18)
2488  .sp  .sp
2489  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
2490  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
2491  supported (it is meaningless).  \fImatch_limit_recursion\fP fields. This is not supported (these fields are
2492    meaningless for DFA matching).
2493  .sp  .sp
2494    PCRE_ERROR_DFA_WSSIZE     (-19)    PCRE_ERROR_DFA_WSSIZE     (-19)
2495  .sp  .sp
# Line 1952  Cambridge CB2 3QH, England. Line 2526  Cambridge CB2 3QH, England.
2526  .rs  .rs
2527  .sp  .sp
2528  .nf  .nf
2529  Last updated: 11 September 2007  Last updated: 06 September 2011
2530  Copyright (c) 1997-2007 University of Cambridge.  Copyright (c) 1997-2011 University of Cambridge.
2531  .fi  .fi

Legend:
Removed from v.243  
changed lines
  Added in v.686

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12