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revision 211 by ph10, Thu Aug 9 09:52:43 2007 UTC revision 513 by ph10, Mon May 3 11:13:37 2010 UTC
# Line 135  Applications can use these to include su Line 135  Applications can use these to include su
135  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,
136  and \fBpcre_exec()\fP are used for compiling and matching regular expressions  and \fBpcre_exec()\fP are used for compiling and matching regular expressions
137  in a Perl-compatible manner. A sample program that demonstrates the simplest  in a Perl-compatible manner. A sample program that demonstrates the simplest
138  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
139  distribution. The  source distribution. A listing of this program is given in the
140    .\" HREF
141    \fBpcredemo\fP
142    .\"
143    documentation, and the
144  .\" HREF  .\" HREF
145  \fBpcresample\fP  \fBpcresample\fP
146  .\"  .\"
147  documentation describes how to run it.  documentation describes how to compile and run it.
148  .P  .P
149  A second matching function, \fBpcre_dfa_exec()\fP, which is not  A second matching function, \fBpcre_dfa_exec()\fP, which is not
150  Perl-compatible, is also provided. This uses a different algorithm for the  Perl-compatible, is also provided. This uses a different algorithm for the
151  matching. The alternative algorithm finds all possible matches (at a given  matching. The alternative algorithm finds all possible matches (at a given
152  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
153  does not return captured substrings. A description of the two matching  lookbehind assertions). However, this algorithm does not return captured
154  algorithms and their advantages and disadvantages is given in the  substrings. A description of the two matching algorithms and their advantages
155    and disadvantages is given in the
156  .\" HREF  .\" HREF
157  \fBpcrematching\fP  \fBpcrematching\fP
158  .\"  .\"
# Line 218  points during a matching operation. Deta Line 223  points during a matching operation. Deta
223  documentation.  documentation.
224  .  .
225  .  .
226    .\" HTML <a name="newlines"></a>
227  .SH NEWLINES  .SH NEWLINES
228  .rs  .rs
229  .sp  .sp
# Line 235  The default default is LF, which is the Line 241  The default default is LF, which is the
241  default can be overridden, either when a pattern is compiled, or when it is  default can be overridden, either when a pattern is compiled, or when it is
242  matched.  matched.
243  .P  .P
244    At compile time, the newline convention can be specified by the \fIoptions\fP
245    argument of \fBpcre_compile()\fP, or it can be specified by special text at the
246    start of the pattern itself; this overrides any other settings. See the
247    .\" HREF
248    \fBpcrepattern\fP
249    .\"
250    page for details of the special character sequences.
251    .P
252  In the PCRE documentation the word "newline" is used to mean "the character or  In the PCRE documentation the word "newline" is used to mean "the character or
253  pair of characters that indicate a line break". The choice of newline  pair of characters that indicate a line break". The choice of newline
254  convention affects the handling of the dot, circumflex, and dollar  convention affects the handling of the dot, circumflex, and dollar
255  metacharacters, the handling of #-comments in /x mode, and, when CRLF is a  metacharacters, the handling of #-comments in /x mode, and, when CRLF is a
256  recognized line ending sequence, the match position advancement for a  recognized line ending sequence, the match position advancement for a
257  non-anchored pattern. The choice of newline convention does not affect the  non-anchored pattern. There is more detail about this in the
258  interpretation of the \en or \er escape sequences.  .\" HTML <a href="#execoptions">
259    .\" </a>
260    section on \fBpcre_exec()\fP options
261    .\"
262    below.
263    .P
264    The choice of newline convention does not affect the interpretation of
265    the \en or \er escape sequences, nor does it affect what \eR matches, which is
266    controlled in a similar way, but by separate options.
267  .  .
268  .  .
269  .SH MULTITHREADING  .SH MULTITHREADING
# Line 300  properties is available; otherwise it is Line 322  properties is available; otherwise it is
322  .sp  .sp
323  The output is an integer whose value specifies the default character sequence  The output is an integer whose value specifies the default character sequence
324  that is recognized as meaning "newline". The four values that are supported  that is recognized as meaning "newline". The four values that are supported
325  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.
326  default should normally be the standard sequence for your operating system.  Though they are derived from ASCII, the same values are returned in EBCDIC
327    environments. The default should normally correspond to the standard sequence
328    for your operating system.
329    .sp
330      PCRE_CONFIG_BSR
331    .sp
332    The output is an integer whose value indicates what character sequences the \eR
333    escape sequence matches by default. A value of 0 means that \eR matches any
334    Unicode line ending sequence; a value of 1 means that \eR matches only CR, LF,
335    or CRLF. The default can be overridden when a pattern is compiled or matched.
336  .sp  .sp
337    PCRE_CONFIG_LINK_SIZE    PCRE_CONFIG_LINK_SIZE
338  .sp  .sp
# Line 323  documentation. Line 354  documentation.
354  .sp  .sp
355    PCRE_CONFIG_MATCH_LIMIT    PCRE_CONFIG_MATCH_LIMIT
356  .sp  .sp
357  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
358  internal matching function calls in a \fBpcre_exec()\fP execution. Further  internal matching function calls in a \fBpcre_exec()\fP execution. Further
359  details are given with \fBpcre_exec()\fP below.  details are given with \fBpcre_exec()\fP below.
360  .sp  .sp
361    PCRE_CONFIG_MATCH_LIMIT_RECURSION    PCRE_CONFIG_MATCH_LIMIT_RECURSION
362  .sp  .sp
363  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
364  recursion when calling the internal matching function in a \fBpcre_exec()\fP  recursion when calling the internal matching function in a \fBpcre_exec()\fP
365  execution. Further details are given with \fBpcre_exec()\fP below.  execution. Further details are given with \fBpcre_exec()\fP below.
366  .sp  .sp
# Line 364  avoiding the use of the stack. Line 395  avoiding the use of the stack.
395  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
396  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
397  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,
398  \fIerrorcodeptr\fP, via which a numerical error code can be returned.  \fIerrorcodeptr\fP, via which a numerical error code can be returned. To avoid
399    too much repetition, we refer just to \fBpcre_compile()\fP below, but the
400    information applies equally to \fBpcre_compile2()\fP.
401  .P  .P
402  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
403  \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 380  argument, which is an address (see below Line 413  argument, which is an address (see below
413  .P  .P
414  The \fIoptions\fP argument contains various bit settings that affect the  The \fIoptions\fP argument contains various bit settings that affect the
415  compilation. It should be zero if no options are required. The available  compilation. It should be zero if no options are required. The available
416  options are described below. Some of them, in particular, those that are  options are described below. Some of them (in particular, those that are
417  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
418  the detailed description in the  within the pattern (see the detailed description in the
419  .\" HREF  .\" HREF
420  \fBpcrepattern\fP  \fBpcrepattern\fP
421  .\"  .\"
422  documentation). For these options, the contents of the \fIoptions\fP argument  documentation). For those options that can be different in different parts of
423  specifies their initial settings at the start of compilation and execution. The  the pattern, the contents of the \fIoptions\fP argument specifies their
424  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,
425  matching as well as at compile time.  PCRE_BSR_\fIxxx\fP, and PCRE_NEWLINE_\fIxxx\fP options can be set at the time
426    of matching as well as at compile time.
427  .P  .P
428  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
429  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
430  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
431  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
432  not try to free it. The offset from the start of the pattern to the character  not try to free it. The byte offset from the start of the pattern to the
433  where the error was discovered is placed in the variable pointed to by  character that was being processed when the error was discovered is placed in
434  \fIerroffset\fP, which must not be NULL. If it is, an immediate error is given.  the variable pointed to by \fIerroffset\fP, which must not be NULL. If it is,
435    an immediate error is given. Some errors are not detected until checks are
436    carried out when the whole pattern has been scanned; in this case the offset is
437    set to the end of the pattern.
438  .P  .P
439  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
440  \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 444  facility, see the Line 481  facility, see the
481  .\"  .\"
482  documentation.  documentation.
483  .sp  .sp
484      PCRE_BSR_ANYCRLF
485      PCRE_BSR_UNICODE
486    .sp
487    These options (which are mutually exclusive) control what the \eR escape
488    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
489    match any Unicode newline sequence. The default is specified when PCRE is
490    built. It can be overridden from within the pattern, or by setting an option
491    when a compiled pattern is matched.
492    .sp
493    PCRE_CASELESS    PCRE_CASELESS
494  .sp  .sp
495  If this bit is set, letters in the pattern match both upper and lower case  If this bit is set, letters in the pattern match both upper and lower case
# Line 507  set, any backslash in a pattern that is Line 553  set, any backslash in a pattern that is
553  special meaning causes an error, thus reserving these combinations for future  special meaning causes an error, thus reserving these combinations for future
554  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
555  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
556  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
557  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)
558    option setting within a pattern.
559  .sp  .sp
560    PCRE_FIRSTLINE    PCRE_FIRSTLINE
561  .sp  .sp
# Line 516  If this option is set, an unanchored pat Line 563  If this option is set, an unanchored pat
563  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
564  over the newline.  over the newline.
565  .sp  .sp
566      PCRE_JAVASCRIPT_COMPAT
567    .sp
568    If this option is set, PCRE's behaviour is changed in some ways so that it is
569    compatible with JavaScript rather than Perl. The changes are as follows:
570    .P
571    (1) A lone closing square bracket in a pattern causes a compile-time error,
572    because this is illegal in JavaScript (by default it is treated as a data
573    character). Thus, the pattern AB]CD becomes illegal when this option is set.
574    .P
575    (2) At run time, a back reference to an unset subpattern group matches an empty
576    string (by default this causes the current matching alternative to fail). A
577    pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
578    an "a" in the subject), whereas it fails by default, for Perl compatibility.
579    .sp
580    PCRE_MULTILINE    PCRE_MULTILINE
581  .sp  .sp
582  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 639  out of use. To avoid confusion, they hav Line 700  out of use. To avoid confusion, they hav
700     9  nothing to repeat     9  nothing to repeat
701    10  [this code is not in use]    10  [this code is not in use]
702    11  internal error: unexpected repeat    11  internal error: unexpected repeat
703    12  unrecognized character after (?    12  unrecognized character after (? or (?-
704    13  POSIX named classes are supported only within a class    13  POSIX named classes are supported only within a class
705    14  missing )    14  missing )
706    15  reference to non-existent subpattern    15  reference to non-existent subpattern
# Line 647  out of use. To avoid confusion, they hav Line 708  out of use. To avoid confusion, they hav
708    17  unknown option bit(s) set    17  unknown option bit(s) set
709    18  missing ) after comment    18  missing ) after comment
710    19  [this code is not in use]    19  [this code is not in use]
711    20  regular expression too large    20  regular expression is too large
712    21  failed to get memory    21  failed to get memory
713    22  unmatched parentheses    22  unmatched parentheses
714    23  internal error: code overflow    23  internal error: code overflow
# Line 676  out of use. To avoid confusion, they hav Line 737  out of use. To avoid confusion, they hav
737    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
738    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
739    48  subpattern name is too long (maximum 32 characters)    48  subpattern name is too long (maximum 32 characters)
740    49  too many named subpatterns (maximum 10,000)    49  too many named subpatterns (maximum 10000)
741    50  [this code is not in use]    50  [this code is not in use]
742    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 (not in UTF-8 mode)
743    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
744    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern not found
745    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
746    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
747    56  inconsistent NEWLINE options"    56  inconsistent NEWLINE options
748    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
749          non-zero number          name/number or by a plain number
750    58  (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number    58  a numbered reference must not be zero
751      59  an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT)
752      60  (*VERB) not recognized
753      61  number is too big
754      62  subpattern name expected
755      63  digit expected after (?+
756      64  ] is an invalid data character in JavaScript compatibility mode
757      65  different names for subpatterns of the same number are not allowed
758      66  (*MARK) must have an argument
759    .sp
760    The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
761    be used if the limits were changed when PCRE was built.
762  .  .
763  .  .
764  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
# Line 705  help speed up matching, \fBpcre_study()\ Line 777  help speed up matching, \fBpcre_study()\
777  results of the study.  results of the study.
778  .P  .P
779  The returned value from \fBpcre_study()\fP can be passed directly to  The returned value from \fBpcre_study()\fP can be passed directly to
780  \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
781  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
782  described  passed; these are described
783  .\" HTML <a href="#extradata">  .\" HTML <a href="#extradata">
784  .\" </a>  .\" </a>
785  below  below
786  .\"  .\"
787  in the section on matching a pattern.  in the section on matching a pattern.
788  .P  .P
789  If studying the pattern does not produce any additional information  If studying the pattern does not produce any useful information,
790  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program
791  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
792  own \fBpcre_extra\fP block.  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.
793  .P  .P
794  The second argument of \fBpcre_study()\fP contains option bits. At present, no  The second argument of \fBpcre_study()\fP contains option bits. At present, no
795  options are defined, and this argument should always be zero.  options are defined, and this argument should always be zero.
# Line 737  This is a typical call to \fBpcre_study\ Line 809  This is a typical call to \fBpcre_study\
809      0,              /* no options exist */      0,              /* no options exist */
810      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
811  .sp  .sp
812  At present, studying a pattern is useful only for non-anchored patterns that do  Studying a pattern does two things: first, a lower bound for the length of
813  not have a single fixed starting character. A bitmap of possible starting  subject string that is needed to match the pattern is computed. This does not
814  bytes is created.  mean that there are any strings of that length that match, but it does
815    guarantee that no shorter strings match. The value is used by
816    \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP to avoid wasting time by trying to
817    match strings that are shorter than the lower bound. You can find out the value
818    in a calling program via the \fBpcre_fullinfo()\fP function.
819    .P
820    Studying a pattern is also useful for non-anchored patterns that do not have a
821    single fixed starting character. A bitmap of possible starting bytes is
822    created. This speeds up finding a position in the subject at which to start
823    matching.
824  .  .
825  .  .
826  .\" HTML <a name="localesupport"></a>  .\" HTML <a name="localesupport"></a>
# Line 882  table indicating a fixed set of bytes fo Line 963  table indicating a fixed set of bytes fo
963  string, a pointer to the table is returned. Otherwise NULL is returned. The  string, a pointer to the table is returned. Otherwise NULL is returned. The
964  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
965  .sp  .sp
966      PCRE_INFO_HASCRORLF
967    .sp
968    Return 1 if the pattern contains any explicit matches for CR or LF characters,
969    otherwise 0. The fourth argument should point to an \fBint\fP variable. An
970    explicit match is either a literal CR or LF character, or \er or \en.
971    .sp
972    PCRE_INFO_JCHANGED    PCRE_INFO_JCHANGED
973  .sp  .sp
974  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
975  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
976  setting changes the local PCRE_DUPNAMES option.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
977  .sp  .sp
978    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
979  .sp  .sp
# Line 898  follows something of variable length. Fo Line 985  follows something of variable length. Fo
985  /^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
986  is -1.  is -1.
987  .sp  .sp
988      PCRE_INFO_MINLENGTH
989    .sp
990    If the pattern was studied and a minimum length for matching subject strings
991    was computed, its value is returned. Otherwise the returned value is -1. The
992    value is a number of characters, not bytes (this may be relevant in UTF-8
993    mode). The fourth argument should point to an \fBint\fP variable. A
994    non-negative value is a lower bound to the length of any matching string. There
995    may not be any strings of that length that do actually match, but every string
996    that does match is at least that long.
997    .sp
998    PCRE_INFO_NAMECOUNT    PCRE_INFO_NAMECOUNT
999    PCRE_INFO_NAMEENTRYSIZE    PCRE_INFO_NAMEENTRYSIZE
1000    PCRE_INFO_NAMETABLE    PCRE_INFO_NAMETABLE
# Line 918  entry; both of these return an \fBint\fP Line 1015  entry; both of these return an \fBint\fP
1015  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
1016  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
1017  are the number of the capturing parenthesis, most significant byte first. The  are the number of the capturing parenthesis, most significant byte first. The
1018  rest of the entry is the corresponding name, zero terminated. The names are in  rest of the entry is the corresponding name, zero terminated.
1019  alphabetical order. When PCRE_DUPNAMES is set, duplicate names are in order of  .P
1020  their parentheses numbers. For example, consider the following pattern (assume  The names are in alphabetical order. Duplicate names may appear if (?| is used
1021  PCRE_EXTENDED is set, so white space - including newlines - is ignored):  to create multiple groups with the same number, as described in the
1022    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1023    .\" </a>
1024    section on duplicate subpattern numbers
1025    .\"
1026    in the
1027    .\" HREF
1028    \fBpcrepattern\fP
1029    .\"
1030    page. Duplicate names for subpatterns with different numbers are permitted only
1031    if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the
1032    table in the order in which they were found in the pattern. In the absence of
1033    (?| this is the order of increasing number; when (?| is used this is not
1034    necessarily the case because later subpatterns may have lower numbers.
1035    .P
1036    As a simple example of the name/number table, consider the following pattern
1037    (assume PCRE_EXTENDED is set, so white space - including newlines - is
1038    ignored):
1039  .sp  .sp
1040  .\" JOIN  .\" JOIN
1041    (?<date> (?<year>(\ed\ed)?\ed\ed) -    (?<date> (?<year>(\ed\ed)?\ed\ed) -
# Line 942  different for each compiled pattern. Line 1056  different for each compiled pattern.
1056  .sp  .sp
1057    PCRE_INFO_OKPARTIAL    PCRE_INFO_OKPARTIAL
1058  .sp  .sp
1059  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
1060  fourth argument should point to an \fBint\fP variable. The  \fBpcre_exec()\fP, otherwise 0. The fourth argument should point to an
1061    \fBint\fP variable. From release 8.00, this always returns 1, because the
1062    restrictions that previously applied to partial matching have been lifted. The
1063  .\" HREF  .\" HREF
1064  \fBpcrepartial\fP  \fBpcrepartial\fP
1065  .\"  .\"
1066  documentation lists the restrictions that apply to patterns when partial  documentation gives details of partial matching.
 matching is used.  
1067  .sp  .sp
1068    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1069  .sp  .sp
# Line 985  variable. Line 1100  variable.
1100  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
1101  a \fBpcre_extra\fP block. That is, it is the value that was passed to  a \fBpcre_extra\fP block. That is, it is the value that was passed to
1102  \fBpcre_malloc()\fP when PCRE was getting memory into which to place the data  \fBpcre_malloc()\fP when PCRE was getting memory into which to place the data
1103  created by \fBpcre_study()\fP. The fourth argument should point to a  created by \fBpcre_study()\fP. If \fBpcre_extra\fP is NULL, or there is no
1104    study data, zero is returned. The fourth argument should point to a
1105  \fBsize_t\fP variable.  \fBsize_t\fP variable.
1106  .  .
1107  .  .
# Line 1047  is different. (This seems a highly unlik Line 1163  is different. (This seems a highly unlik
1163  .P  .P
1164  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
1165  compiled pattern, which is passed in the \fIcode\fP argument. If the  compiled pattern, which is passed in the \fIcode\fP argument. If the
1166  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
1167  \fIextra\fP argument. This function is the main matching facility of the  \fIextra\fP argument. This function is the main matching facility of the
1168  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
1169  also an alternative matching function, which is described  also an alternative matching function, which is described
# Line 1097  fields (not necessarily in this order): Line 1213  fields (not necessarily in this order):
1213    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1214    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1215    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1216      unsigned char **\fImark\fP;
1217  .sp  .sp
1218  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
1219  are set. The flag bits are:  are set. The flag bits are:
# Line 1106  are set. The flag bits are: Line 1223  are set. The flag bits are:
1223    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1224    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1225    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1226      PCRE_EXTRA_MARK
1227  .sp  .sp
1228  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 is set in the
1229  \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with  \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with
# Line 1115  the block by setting the other fields an Line 1233  the block by setting the other fields an
1233  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
1234  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,
1235  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
1236  classic example is the use of nested unlimited repeats.  classic example is a pattern that uses nested unlimited repeats.
1237  .P  .P
1238  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly
1239  (sometimes recursively). The limit set by \fImatch_limit\fP is imposed on the  (sometimes recursively). The limit set by \fImatch_limit\fP is imposed on the
# Line 1148  with a \fBpcre_extra\fP block in which \ Line 1266  with a \fBpcre_extra\fP block in which \
1266  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
1267  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.
1268  .P  .P
1269  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,
1270  which is described in the  and is described in the
1271  .\" HREF  .\" HREF
1272  \fBpcrecallout\fP  \fBpcrecallout\fP
1273  .\"  .\"
# Line 1168  called. See the Line 1286  called. See the
1286  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1287  .\"  .\"
1288  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1289    .P
1290    If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must
1291    be set to point to a \fBchar *\fP variable. If the pattern contains any
1292    backtracking control verbs such as (*MARK:NAME), and the execution ends up with
1293    a name to pass back, a pointer to the name string (zero terminated) is placed
1294    in the variable pointed to by the \fImark\fP field. The names are within the
1295    compiled pattern; if you wish to retain such a name you must copy it before
1296    freeing the memory of a compiled pattern. If there is no name to pass back, the
1297    variable pointed to by the \fImark\fP field set to NULL. For details of the
1298    backtracking control verbs, see the section entitled
1299    .\" HTML <a href="pcrepattern#backtrackcontrol">
1300    .\" </a>
1301    "Backtracking control"
1302    .\"
1303    in the
1304    .\" HREF
1305    \fBpcrepattern\fP
1306    .\"
1307    documentation.
1308    .
1309  .  .
1310    .\" HTML <a name="execoptions"></a>
1311  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
1312  .rs  .rs
1313  .sp  .sp
1314  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
1315  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,
1316  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1317    PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
1318    PCRE_PARTIAL_HARD.
1319  .sp  .sp
1320    PCRE_ANCHORED    PCRE_ANCHORED
1321  .sp  .sp
# Line 1183  matching position. If a pattern was comp Line 1324  matching position. If a pattern was comp
1324  to be anchored by virtue of its contents, it cannot be made unachored at  to be anchored by virtue of its contents, it cannot be made unachored at
1325  matching time.  matching time.
1326  .sp  .sp
1327      PCRE_BSR_ANYCRLF
1328      PCRE_BSR_UNICODE
1329    .sp
1330    These options (which are mutually exclusive) control what the \eR escape
1331    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1332    match any Unicode newline sequence. These options override the choice that was
1333    made or defaulted when the pattern was compiled.
1334    .sp
1335    PCRE_NEWLINE_CR    PCRE_NEWLINE_CR
1336    PCRE_NEWLINE_LF    PCRE_NEWLINE_LF
1337    PCRE_NEWLINE_CRLF    PCRE_NEWLINE_CRLF
# Line 1194  the pattern was compiled. For details, s Line 1343  the pattern was compiled. For details, s
1343  \fBpcre_compile()\fP above. During matching, the newline choice affects the  \fBpcre_compile()\fP above. During matching, the newline choice affects the
1344  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1345  the way the match position is advanced after a match failure for an unanchored  the way the match position is advanced after a match failure for an unanchored
1346  pattern. When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is  pattern.
1347  set, and a match attempt fails when the current position is at a CRLF sequence,  .P
1348  the match position is advanced by two characters instead of one, in other  When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a
1349  words, to after the CRLF.  match attempt for an unanchored pattern fails when the current position is at a
1350    CRLF sequence, and the pattern contains no explicit matches for CR or LF
1351    characters, the match position is advanced by two characters instead of one, in
1352    other words, to after the CRLF.
1353    .P
1354    The above rule is a compromise that makes the most common cases work as
1355    expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1356    set), it does not match the string "\er\enA" because, after failing at the
1357    start, it skips both the CR and the LF before retrying. However, the pattern
1358    [\er\en]A does match that string, because it contains an explicit CR or LF
1359    reference, and so advances only by one character after the first failure.
1360    .P
1361    An explicit match for CR of LF is either a literal appearance of one of those
1362    characters, or one of the \er or \en escape sequences. Implicit matches such as
1363    [^X] do not count, nor does \es (which includes CR and LF in the characters
1364    that it matches).
1365    .P
1366    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1367    valid newline sequence and explicit \er or \en escapes appear in the pattern.
1368  .sp  .sp
1369    PCRE_NOTBOL    PCRE_NOTBOL
1370  .sp  .sp
# Line 1223  match the empty string, the entire match Line 1390  match the empty string, the entire match
1390  .sp  .sp
1391    a?b?    a?b?
1392  .sp  .sp
1393  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
1394  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
1395  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".
1396  .P  .sp
1397  Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case    PCRE_NOTEMPTY_ATSTART
1398  of a pattern match of the empty string within its \fBsplit()\fP function, and  .sp
1399  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
1400  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
1401  PCRE_NOTEMPTY and PCRE_ANCHORED, and then if that fails by advancing the  can occur only if the pattern contains \eK.
1402  starting offset (see below) and trying an ordinary match again. There is some  .P
1403  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
1404    does make a special case of a pattern match of the empty string within its
1405    \fBsplit()\fP function, and when using the /g modifier. It is possible to
1406    emulate Perl's behaviour after matching a null string by first trying the match
1407    again at the same offset with PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED, and then
1408    if that fails, by advancing the starting offset (see below) and trying an
1409    ordinary match again. There is some code that demonstrates how to do this in
1410    the
1411    .\" HREF
1412    \fBpcredemo\fP
1413    .\"
1414    sample program.
1415    .sp
1416      PCRE_NO_START_OPTIMIZE
1417    .sp
1418    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1419    a match, in order to speed up the process. For example, if it is known that a
1420    match must start with a specific character, it searches the subject for that
1421    character, and fails immediately if it cannot find it, without actually running
1422    the main matching function. When callouts are in use, these optimizations can
1423    cause them to be skipped. This option disables the "start-up" optimizations,
1424    causing performance to suffer, but ensuring that the callouts do occur.
1425  .sp  .sp
1426    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1427  .sp  .sp
# Line 1264  PCRE_NO_UTF8_CHECK is set, the effect of Line 1452  PCRE_NO_UTF8_CHECK is set, the effect of
1452  subject, or a value of \fIstartoffset\fP that does not point to the start of a  subject, or a value of \fIstartoffset\fP that does not point to the start of a
1453  UTF-8 character, is undefined. Your program may crash.  UTF-8 character, is undefined. Your program may crash.
1454  .sp  .sp
1455    PCRE_PARTIAL    PCRE_PARTIAL_HARD
1456      PCRE_PARTIAL_SOFT
1457  .sp  .sp
1458  This option turns on the partial matching feature. If the subject string fails  These options turn on the partial matching feature. For backwards
1459  to match the pattern, but at some point during the matching process the end of  compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match
1460  the subject was reached (that is, the subject partially matches the pattern and  occurs if the end of the subject string is reached successfully, but there are
1461  the failure to match occurred only because there were not enough subject  not enough subject characters to complete the match. If this happens when
1462  characters), \fBpcre_exec()\fP returns PCRE_ERROR_PARTIAL instead of  PCRE_PARTIAL_HARD is set, \fBpcre_exec()\fP immediately returns
1463  PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is used, there are restrictions on what  PCRE_ERROR_PARTIAL. Otherwise, if PCRE_PARTIAL_SOFT is set, matching continues
1464  may appear in the pattern. These are discussed in the  by testing any other alternatives. Only if they all fail is PCRE_ERROR_PARTIAL
1465    returned (instead of PCRE_ERROR_NOMATCH). The portion of the string that
1466    was inspected when the partial match was found is set as the first matching
1467    string. There is a more detailed discussion in the
1468  .\" HREF  .\" HREF
1469  \fBpcrepartial\fP  \fBpcrepartial\fP
1470  .\"  .\"
# Line 1282  documentation. Line 1474  documentation.
1474  .rs  .rs
1475  .sp  .sp
1476  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
1477  \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
1478  \fIstartoffset\fP. In UTF-8 mode, the byte offset must point to the start of a  in \fIstartoffset\fP. In UTF-8 mode, the byte offset must point to the start of
1479  UTF-8 character. Unlike the pattern string, the subject may contain binary zero  a UTF-8 character. Unlike the pattern string, the subject may contain binary
1480  bytes. When the starting offset is zero, the search for a match starts at the  zero bytes. When the starting offset is zero, the search for a match starts at
1481  beginning of the subject, and this is by far the most common case.  the beginning of the subject, and this is by far the most common case.
1482  .P  .P
1483  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
1484  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 1320  pattern. Following the usage in Jeffrey Line 1512  pattern. Following the usage in Jeffrey
1512  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
1513  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1514  .P  .P
1515  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
1516  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
1517  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
1518  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1519  .P  .P
1520  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,
1521  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
1522  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1523  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1524  \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
1525  rounded down.  rounded down.
1526  .P  .P
1527  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1528  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1529  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
1530  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
1531  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
1532  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
1533  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1534  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1535  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
1536  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
1537  capturing subpatterns, the return value from a successful match is 1,  used for the first capturing subpattern, and so on. The value returned by
1538  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.
1539    For example, if two substrings have been captured, the returned value is 3. If
1540    there are no capturing subpatterns, the return value from a successful match is
1541    1, indicating that just the first pair of offsets has been set.
1542  .P  .P
1543  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
1544  string that it matched that is returned.  string that it matched that is returned.
1545  .P  .P
1546  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
1547  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
1548  returns a value of zero. In particular, if the substring offsets are not of  returns a value of zero. If the substring offsets are not of interest,
1549  interest, \fBpcre_exec()\fP may be called with \fIovector\fP passed as NULL and  \fBpcre_exec()\fP may be called with \fIovector\fP passed as NULL and
1550  \fIovecsize\fP as zero. However, if the pattern contains back references and  \fIovecsize\fP as zero. However, if the pattern contains back references and
1551  the \fIovector\fP is not big enough to remember the related substrings, PCRE  the \fIovector\fP is not big enough to remember the related substrings, PCRE
1552  has to get additional memory for use during matching. Thus it is usually  has to get additional memory for use during matching. Thus it is usually
1553  advisable to supply an \fIovector\fP.  advisable to supply an \fIovector\fP.
1554  .P  .P
1555  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
1556  subpatterns there are in a compiled pattern. The smallest size for  subpatterns there are in a compiled pattern. The smallest size for
1557  \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
1558  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 1462  documentation for details of partial mat Line 1657  documentation for details of partial mat
1657  .sp  .sp
1658    PCRE_ERROR_BADPARTIAL     (-13)    PCRE_ERROR_BADPARTIAL     (-13)
1659  .sp  .sp
1660  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
1661  are not supported for partial matching. See the  option was used with a compiled pattern containing items that were not
1662  .\" HREF  supported for partial matching. From release 8.00 onwards, there are no
1663  \fBpcrepartial\fP  restrictions on partial matching.
 .\"  
 documentation for details of partial matching.  
1664  .sp  .sp
1665    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
1666  .sp  .sp
# Line 1637  These functions call \fBpcre_get_stringn Line 1830  These functions call \fBpcre_get_stringn
1830  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1831  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,
1832  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
1833  .  .P
1834    \fBWarning:\fP If the pattern uses the (?| feature to set up multiple
1835    subpatterns with the same number, as described in the
1836    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1837    .\" </a>
1838    section on duplicate subpattern numbers
1839    .\"
1840    in the
1841    .\" HREF
1842    \fBpcrepattern\fP
1843    .\"
1844    page, you cannot use names to distinguish the different subpatterns, because
1845    names are not included in the compiled code. The matching process uses only
1846    numbers. For this reason, the use of different names for subpatterns of the
1847    same number causes an error at compile time.
1848  .  .
1849  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
1850  .rs  .rs
# Line 1647  the behaviour may not be what you want ( Line 1854  the behaviour may not be what you want (
1854  .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);  .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
1855  .PP  .PP
1856  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
1857  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
1858  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
1859  example is shown in the  such subpatterns are named, they are required to use the same names.)
1860    .P
1861    Normally, patterns with duplicate names are such that in any one match, only
1862    one of the named subpatterns participates. An example is shown in the
1863  .\" HREF  .\" HREF
1864  \fBpcrepattern\fP  \fBpcrepattern\fP
1865  .\"  .\"
# Line 1713  a compiled pattern, using a matching alg Line 1923  a compiled pattern, using a matching alg
1923  just once, and does not backtrack. This has different characteristics to the  just once, and does not backtrack. This has different characteristics to the
1924  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
1925  patterns are not supported. Nevertheless, there are times when this kind of  patterns are not supported. Nevertheless, there are times when this kind of
1926  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
1927  the  list of features that \fBpcre_dfa_exec()\fP does not support, see the
1928  .\" HREF  .\" HREF
1929  \fBpcrematching\fP  \fBpcrematching\fP
1930  .\"  .\"
# Line 1753  Here is an example of a simple call to \ Line 1963  Here is an example of a simple call to \
1963  .sp  .sp
1964  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
1965  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,
1966  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1967  PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last three of these are  PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST,
1968  the same as for \fBpcre_exec()\fP, so their description is not repeated here.  and PCRE_DFA_RESTART. All but the last four of these are exactly the same as
1969  .sp  for \fBpcre_exec()\fP, so their description is not repeated here.
1970    PCRE_PARTIAL  .sp
1971  .sp    PCRE_PARTIAL_HARD
1972  This has the same general effect as it does for \fBpcre_exec()\fP, but the    PCRE_PARTIAL_SOFT
1973  details are slightly different. When PCRE_PARTIAL is set for  .sp
1974  \fBpcre_dfa_exec()\fP, the return code PCRE_ERROR_NOMATCH is converted into  These have the same general effect as they do for \fBpcre_exec()\fP, but the
1975  PCRE_ERROR_PARTIAL if the end of the subject is reached, there have been no  details are slightly different. When PCRE_PARTIAL_HARD is set for
1976  complete matches, but there is still at least one matching possibility. The  \fBpcre_dfa_exec()\fP, it returns PCRE_ERROR_PARTIAL if the end of the subject
1977  portion of the string that provided the partial match is set as the first  is reached and there is still at least one matching possibility that requires
1978  matching string.  additional characters. This happens even if some complete matches have also
1979    been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
1980    is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached,
1981    there have been no complete matches, but there is still at least one matching
1982    possibility. The portion of the string that was inspected when the longest
1983    partial match was found is set as the first matching string in both cases.
1984  .sp  .sp
1985    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
1986  .sp  .sp
# Line 1776  matching point in the subject string. Line 1991  matching point in the subject string.
1991  .sp  .sp
1992    PCRE_DFA_RESTART    PCRE_DFA_RESTART
1993  .sp  .sp
1994  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
1995  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
1996  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
1997  option requests this action; when it is set, the \fIworkspace\fP and  \fIworkspace\fP and \fIwscount\fP options must reference the same vector as
1998  \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
1999  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  
2000  .\" HREF  .\" HREF
2001  \fBpcrepartial\fP  \fBpcrepartial\fP
2002  .\"  .\"
# Line 1886  Cambridge CB2 3QH, England. Line 2100  Cambridge CB2 3QH, England.
2100  .rs  .rs
2101  .sp  .sp
2102  .nf  .nf
2103  Last updated: 09 August 2007  Last updated: 03 May 2010
2104  Copyright (c) 1997-2007 University of Cambridge.  Copyright (c) 1997-2010 University of Cambridge.
2105  .fi  .fi

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