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revision 196 by ph10, Mon Jul 30 13:44:50 2007 UTC revision 455 by ph10, Sat Sep 26 19:12:32 2009 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 380  argument, which is an address (see below Line 411  argument, which is an address (see below
411  .P  .P
412  The \fIoptions\fP argument contains various bit settings that affect the  The \fIoptions\fP argument contains various bit settings that affect the
413  compilation. It should be zero if no options are required. The available  compilation. It should be zero if no options are required. The available
414  options are described below. Some of them, in particular, those that are  options are described below. Some of them (in particular, those that are
415  compatible with Perl, can also be set and unset from within the pattern (see  compatible with Perl, but also some others) can also be set and unset from
416  the detailed description in the  within the pattern (see the detailed description in the
417  .\" HREF  .\" HREF
418  \fBpcrepattern\fP  \fBpcrepattern\fP
419  .\"  .\"
420  documentation). For these options, the contents of the \fIoptions\fP argument  documentation). For those options that can be different in different parts of
421  specifies their initial settings at the start of compilation and execution. The  the pattern, the contents of the \fIoptions\fP argument specifies their initial
422  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 and
423  matching as well as at compile time.  PCRE_NEWLINE_\fIxxx\fP options can be set at the time of matching as well as at
424    compile time.
425  .P  .P
426  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
427  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
428  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
429  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
430  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
431  where the error was discovered is placed in the variable pointed to by  character that was being processes when the error was discovered is placed in
432  \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,
433    an immediate error is given. Some errors are not detected until checks are
434    carried out when the whole pattern has been scanned; in this case the offset is
435    set to the end of the pattern.
436  .P  .P
437  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
438  \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 479  facility, see the
479  .\"  .\"
480  documentation.  documentation.
481  .sp  .sp
482      PCRE_BSR_ANYCRLF
483      PCRE_BSR_UNICODE
484    .sp
485    These options (which are mutually exclusive) control what the \eR escape
486    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
487    match any Unicode newline sequence. The default is specified when PCRE is
488    built. It can be overridden from within the pattern, or by setting an option
489    when a compiled pattern is matched.
490    .sp
491    PCRE_CASELESS    PCRE_CASELESS
492  .sp  .sp
493  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 516  If this option is set, an unanchored pat Line 560  If this option is set, an unanchored pat
560  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
561  over the newline.  over the newline.
562  .sp  .sp
563      PCRE_JAVASCRIPT_COMPAT
564    .sp
565    If this option is set, PCRE's behaviour is changed in some ways so that it is
566    compatible with JavaScript rather than Perl. The changes are as follows:
567    .P
568    (1) A lone closing square bracket in a pattern causes a compile-time error,
569    because this is illegal in JavaScript (by default it is treated as a data
570    character). Thus, the pattern AB]CD becomes illegal when this option is set.
571    .P
572    (2) At run time, a back reference to an unset subpattern group matches an empty
573    string (by default this causes the current matching alternative to fail). A
574    pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
575    an "a" in the subject), whereas it fails by default, for Perl compatibility.
576    .sp
577    PCRE_MULTILINE    PCRE_MULTILINE
578  .sp  .sp
579  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 601  page. Line 659  page.
659    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
660  .sp  .sp
661  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
662  automatically checked. If an invalid UTF-8 sequence of bytes is found,  automatically checked. There is a discussion about the
663  \fBpcre_compile()\fP returns an error. If you already know that your pattern is  .\" HTML <a href="pcre.html#utf8strings">
664  valid, and you want to skip this check for performance reasons, you can set the  .\" </a>
665  PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid  validity of UTF-8 strings
666  UTF-8 string as a pattern is undefined. It may cause your program to crash.  .\"
667  Note that this option can also be passed to \fBpcre_exec()\fP and  in the main
668  \fBpcre_dfa_exec()\fP, to suppress the UTF-8 validity checking of subject  .\" HREF
669  strings.  \fBpcre\fP
670    .\"
671    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_compile()\fP
672    returns an error. If you already know that your pattern is valid, and you want
673    to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
674    option. When it is set, the effect of passing an invalid UTF-8 string as a
675    pattern is undefined. It may cause your program to crash. Note that this option
676    can also be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress
677    the UTF-8 validity checking of subject strings.
678  .  .
679  .  .
680  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 631  out of use. To avoid confusion, they hav Line 697  out of use. To avoid confusion, they hav
697     9  nothing to repeat     9  nothing to repeat
698    10  [this code is not in use]    10  [this code is not in use]
699    11  internal error: unexpected repeat    11  internal error: unexpected repeat
700    12  unrecognized character after (?    12  unrecognized character after (? or (?-
701    13  POSIX named classes are supported only within a class    13  POSIX named classes are supported only within a class
702    14  missing )    14  missing )
703    15  reference to non-existent subpattern    15  reference to non-existent subpattern
# Line 639  out of use. To avoid confusion, they hav Line 705  out of use. To avoid confusion, they hav
705    17  unknown option bit(s) set    17  unknown option bit(s) set
706    18  missing ) after comment    18  missing ) after comment
707    19  [this code is not in use]    19  [this code is not in use]
708    20  regular expression too large    20  regular expression is too large
709    21  failed to get memory    21  failed to get memory
710    22  unmatched parentheses    22  unmatched parentheses
711    23  internal error: code overflow    23  internal error: code overflow
# Line 668  out of use. To avoid confusion, they hav Line 734  out of use. To avoid confusion, they hav
734    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
735    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
736    48  subpattern name is too long (maximum 32 characters)    48  subpattern name is too long (maximum 32 characters)
737    49  too many named subpatterns (maximum 10,000)    49  too many named subpatterns (maximum 10000)
738    50  repeated subpattern is too long    50  [this code is not in use]
739    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 (not in UTF-8 mode)
740    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
741    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern not found
742    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
743    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
744    56  inconsistent NEWLINE options"    56  inconsistent NEWLINE options
745    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
746          non-zero number          name/number or by a plain number
747    58  (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number    58  a numbered reference must not be zero
748      59  (*VERB) with an argument is not supported
749      60  (*VERB) not recognized
750      61  number is too big
751      62  subpattern name expected
752      63  digit expected after (?+
753      64  ] is an invalid data character in JavaScript compatibility mode
754    .sp
755    The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
756    be used if the limits were changed when PCRE was built.
757  .  .
758  .  .
759  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
# Line 697  help speed up matching, \fBpcre_study()\ Line 772  help speed up matching, \fBpcre_study()\
772  results of the study.  results of the study.
773  .P  .P
774  The returned value from \fBpcre_study()\fP can be passed directly to  The returned value from \fBpcre_study()\fP can be passed directly to
775  \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
776  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
777  described  passed; these are described
778  .\" HTML <a href="#extradata">  .\" HTML <a href="#extradata">
779  .\" </a>  .\" </a>
780  below  below
781  .\"  .\"
782  in the section on matching a pattern.  in the section on matching a pattern.
783  .P  .P
784  If studying the pattern does not produce any additional information  If studying the pattern does not produce any useful information,
785  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program
786  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
787  own \fBpcre_extra\fP block.  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.
788  .P  .P
789  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
790  options are defined, and this argument should always be zero.  options are defined, and this argument should always be zero.
# Line 729  This is a typical call to \fBpcre_study\ Line 804  This is a typical call to \fBpcre_study\
804      0,              /* no options exist */      0,              /* no options exist */
805      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
806  .sp  .sp
807  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
808  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
809  bytes is created.  mean that there are any strings of that length that match, but it does
810    guarantee that no shorter strings match. The value is used by
811    \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP to avoid wasting time by trying to
812    match strings that are shorter than the lower bound. You can find out the value
813    in a calling program via the \fBpcre_fullinfo()\fP function.
814    .P
815    Studying a pattern is also useful for non-anchored patterns that do not have a
816    single fixed starting character. A bitmap of possible starting bytes is
817    created. This speeds up finding a position in the subject at which to start
818    matching.
819  .  .
820  .  .
821  .\" HTML <a name="localesupport"></a>  .\" HTML <a name="localesupport"></a>
# Line 874  table indicating a fixed set of bytes fo Line 958  table indicating a fixed set of bytes fo
958  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
959  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
960  .sp  .sp
961      PCRE_INFO_HASCRORLF
962    .sp
963    Return 1 if the pattern contains any explicit matches for CR or LF characters,
964    otherwise 0. The fourth argument should point to an \fBint\fP variable. An
965    explicit match is either a literal CR or LF character, or \er or \en.
966    .sp
967    PCRE_INFO_JCHANGED    PCRE_INFO_JCHANGED
968  .sp  .sp
969  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
970  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
971  setting changes the local PCRE_DUPNAMES option.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
972  .sp  .sp
973    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
974  .sp  .sp
# Line 890  follows something of variable length. Fo Line 980  follows something of variable length. Fo
980  /^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
981  is -1.  is -1.
982  .sp  .sp
983      PCRE_INFO_MINLENGTH
984    .sp
985    If the pattern was studied and a minimum length for matching subject strings
986    was computed, its value is returned. Otherwise the returned value is -1. The
987    value is a number of characters, not bytes (there may be a difference in UTF-8
988    mode). The fourth argument should point to an \fBint\fP variable. A
989    non-negative value is a lower bound to the length of any matching string. There
990    may not be any strings of that length that do actually match, but every string
991    that does match is at least that long.
992    .sp
993    PCRE_INFO_NAMECOUNT    PCRE_INFO_NAMECOUNT
994    PCRE_INFO_NAMEENTRYSIZE    PCRE_INFO_NAMEENTRYSIZE
995    PCRE_INFO_NAMETABLE    PCRE_INFO_NAMETABLE
# Line 934  different for each compiled pattern. Line 1034  different for each compiled pattern.
1034  .sp  .sp
1035    PCRE_INFO_OKPARTIAL    PCRE_INFO_OKPARTIAL
1036  .sp  .sp
1037  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
1038  fourth argument should point to an \fBint\fP variable. The  \fBpcre_exec()\fP, otherwise 0. The fourth argument should point to an
1039    \fBint\fP variable. From release 8.00, this always returns 1, because the
1040    restrictions that previously applied to partial matching have been lifted. The
1041  .\" HREF  .\" HREF
1042  \fBpcrepartial\fP  \fBpcrepartial\fP
1043  .\"  .\"
1044  documentation lists the restrictions that apply to patterns when partial  documentation gives details of partial matching.
 matching is used.  
1045  .sp  .sp
1046    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1047  .sp  .sp
# Line 977  variable. Line 1078  variable.
1078  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
1079  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
1080  \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
1081  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
1082    study data, zero is returned. The fourth argument should point to a
1083  \fBsize_t\fP variable.  \fBsize_t\fP variable.
1084  .  .
1085  .  .
# Line 1039  is different. (This seems a highly unlik Line 1141  is different. (This seems a highly unlik
1141  .P  .P
1142  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
1143  compiled pattern, which is passed in the \fIcode\fP argument. If the  compiled pattern, which is passed in the \fIcode\fP argument. If the
1144  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
1145  \fIextra\fP argument. This function is the main matching facility of the  \fIextra\fP argument. This function is the main matching facility of the
1146  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
1147  also an alternative matching function, which is described  also an alternative matching function, which is described
# Line 1140  with a \fBpcre_extra\fP block in which \ Line 1242  with a \fBpcre_extra\fP block in which \
1242  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
1243  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.
1244  .P  .P
1245  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,
1246  which is described in the  and is described in the
1247  .\" HREF  .\" HREF
1248  \fBpcrecallout\fP  \fBpcrecallout\fP
1249  .\"  .\"
# Line 1161  called. See the Line 1263  called. See the
1263  .\"  .\"
1264  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1265  .  .
1266    .\" HTML <a name="execoptions"></a>
1267  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
1268  .rs  .rs
1269  .sp  .sp
1270  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
1271  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,
1272  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1273    PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
1274    PCRE_PARTIAL_HARD.
1275  .sp  .sp
1276    PCRE_ANCHORED    PCRE_ANCHORED
1277  .sp  .sp
# Line 1175  matching position. If a pattern was comp Line 1280  matching position. If a pattern was comp
1280  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
1281  matching time.  matching time.
1282  .sp  .sp
1283      PCRE_BSR_ANYCRLF
1284      PCRE_BSR_UNICODE
1285    .sp
1286    These options (which are mutually exclusive) control what the \eR escape
1287    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1288    match any Unicode newline sequence. These options override the choice that was
1289    made or defaulted when the pattern was compiled.
1290    .sp
1291    PCRE_NEWLINE_CR    PCRE_NEWLINE_CR
1292    PCRE_NEWLINE_LF    PCRE_NEWLINE_LF
1293    PCRE_NEWLINE_CRLF    PCRE_NEWLINE_CRLF
# Line 1186  the pattern was compiled. For details, s Line 1299  the pattern was compiled. For details, s
1299  \fBpcre_compile()\fP above. During matching, the newline choice affects the  \fBpcre_compile()\fP above. During matching, the newline choice affects the
1300  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1301  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
1302  pattern. When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is  pattern.
1303  set, and a match attempt fails when the current position is at a CRLF sequence,  .P
1304  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
1305  words, to after the CRLF.  match attempt for an unanchored pattern fails when the current position is at a
1306    CRLF sequence, and the pattern contains no explicit matches for CR or LF
1307    characters, the match position is advanced by two characters instead of one, in
1308    other words, to after the CRLF.
1309    .P
1310    The above rule is a compromise that makes the most common cases work as
1311    expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1312    set), it does not match the string "\er\enA" because, after failing at the
1313    start, it skips both the CR and the LF before retrying. However, the pattern
1314    [\er\en]A does match that string, because it contains an explicit CR or LF
1315    reference, and so advances only by one character after the first failure.
1316    .P
1317    An explicit match for CR of LF is either a literal appearance of one of those
1318    characters, or one of the \er or \en escape sequences. Implicit matches such as
1319    [^X] do not count, nor does \es (which includes CR and LF in the characters
1320    that it matches).
1321    .P
1322    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1323    valid newline sequence and explicit \er or \en escapes appear in the pattern.
1324  .sp  .sp
1325    PCRE_NOTBOL    PCRE_NOTBOL
1326  .sp  .sp
# Line 1215  match the empty string, the entire match Line 1346  match the empty string, the entire match
1346  .sp  .sp
1347    a?b?    a?b?
1348  .sp  .sp
1349  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
1350  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
1351  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".
1352  .P  .sp
1353  Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case    PCRE_NOTEMPTY_ATSTART
1354  of a pattern match of the empty string within its \fBsplit()\fP function, and  .sp
1355  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
1356  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
1357  PCRE_NOTEMPTY and PCRE_ANCHORED, and then if that fails by advancing the  can occur only if the pattern contains \eK.
1358  starting offset (see below) and trying an ordinary match again. There is some  .P
1359  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
1360    does make a special case of a pattern match of the empty string within its
1361    \fBsplit()\fP function, and when using the /g modifier. It is possible to
1362    emulate Perl's behaviour after matching a null string by first trying the match
1363    again at the same offset with PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED, and then
1364    if that fails, by advancing the starting offset (see below) and trying an
1365    ordinary match again. There is some code that demonstrates how to do this in
1366    the
1367    .\" HREF
1368    \fBpcredemo\fP
1369    .\"
1370    sample program.
1371    .sp
1372      PCRE_NO_START_OPTIMIZE
1373    .sp
1374    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1375    a match, in order to speed up the process. For example, if it is known that a
1376    match must start with a specific character, it searches the subject for that
1377    character, and fails immediately if it cannot find it, without actually running
1378    the main matching function. When callouts are in use, these optimizations can
1379    cause them to be skipped. This option disables the "start-up" optimizations,
1380    causing performance to suffer, but ensuring that the callouts do occur.
1381  .sp  .sp
1382    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1383  .sp  .sp
1384  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8
1385  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1386  The value of \fIstartoffset\fP is also checked to ensure that it points to the  The value of \fIstartoffset\fP is also checked to ensure that it points to the
1387  start of a UTF-8 character. If an invalid UTF-8 sequence of bytes is found,  start of a UTF-8 character. There is a discussion about the validity of UTF-8
1388  \fBpcre_exec()\fP returns the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP  strings in the
1389  contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.  .\" HTML <a href="pcre.html#utf8strings">
1390    .\" </a>
1391    section on UTF-8 support
1392    .\"
1393    in the main
1394    .\" HREF
1395    \fBpcre\fP
1396    .\"
1397    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1398    the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains an invalid value,
1399    PCRE_ERROR_BADUTF8_OFFSET is returned.
1400  .P  .P
1401  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
1402  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
# Line 1246  PCRE_NO_UTF8_CHECK is set, the effect of Line 1408  PCRE_NO_UTF8_CHECK is set, the effect of
1408  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
1409  UTF-8 character, is undefined. Your program may crash.  UTF-8 character, is undefined. Your program may crash.
1410  .sp  .sp
1411    PCRE_PARTIAL    PCRE_PARTIAL_HARD
1412      PCRE_PARTIAL_SOFT
1413  .sp  .sp
1414  This option turns on the partial matching feature. If the subject string fails  These options turn on the partial matching feature. For backwards
1415  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
1416  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
1417  the failure to match occurred only because there were not enough subject  not enough subject characters to complete the match. If this happens when
1418  characters), \fBpcre_exec()\fP returns PCRE_ERROR_PARTIAL instead of  PCRE_PARTIAL_HARD is set, \fBpcre_exec()\fP immediately returns
1419  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
1420  may appear in the pattern. These are discussed in the  by testing any other alternatives. Only if they all fail is PCRE_ERROR_PARTIAL
1421    returned (instead of PCRE_ERROR_NOMATCH). The portion of the string that
1422    was inspected when the partial match was found is set as the first matching
1423    string. There is a more detailed discussion in the
1424  .\" HREF  .\" HREF
1425  \fBpcrepartial\fP  \fBpcrepartial\fP
1426  .\"  .\"
# Line 1264  documentation. Line 1430  documentation.
1430  .rs  .rs
1431  .sp  .sp
1432  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
1433  \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
1434  \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
1435  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
1436  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
1437  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.
1438  .P  .P
1439  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
1440  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 1302  pattern. Following the usage in Jeffrey Line 1468  pattern. Following the usage in Jeffrey
1468  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
1469  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1470  .P  .P
1471  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
1472  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
1473  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
1474  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1475  .P  .P
1476  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,
1477  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
1478  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1479  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1480  \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
1481  rounded down.  rounded down.
1482  .P  .P
1483  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1484  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1485  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
1486  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
1487  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
1488  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
1489  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1490  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1491  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
1492  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
1493  capturing subpatterns, the return value from a successful match is 1,  used for the first capturing subpattern, and so on. The value returned by
1494  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.
1495    For example, if two substrings have been captured, the returned value is 3. If
1496    there are no capturing subpatterns, the return value from a successful match is
1497    1, indicating that just the first pair of offsets has been set.
1498  .P  .P
1499  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
1500  string that it matched that is returned.  string that it matched that is returned.
1501  .P  .P
1502  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
1503  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
1504  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,
1505  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
1506  \fIovecsize\fP as zero. However, if the pattern contains back references and  \fIovecsize\fP as zero. However, if the pattern contains back references and
1507  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
1508  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
# Line 1444  documentation for details of partial mat Line 1613  documentation for details of partial mat
1613  .sp  .sp
1614    PCRE_ERROR_BADPARTIAL     (-13)    PCRE_ERROR_BADPARTIAL     (-13)
1615  .sp  .sp
1616  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
1617  are not supported for partial matching. See the  option was used with a compiled pattern containing items that were not
1618  .\" HREF  supported for partial matching. From release 8.00 onwards, there are no
1619  \fBpcrepartial\fP  restrictions on partial matching.
 .\"  
 documentation for details of partial matching.  
1620  .sp  .sp
1621    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
1622  .sp  .sp
# Line 1466  The internal recursion limit, as specifi Line 1633  The internal recursion limit, as specifi
1633  field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the  field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the
1634  description above.  description above.
1635  .sp  .sp
   PCRE_ERROR_NULLWSLIMIT    (-22)  
 .sp  
 When a parenthesized subpattern that can match an empty substring is repeated  
 with an unbounded upper limit, the subject position at the start of the group  
 must be remembered, so that a test for an empty string can be made when the end  
 of the group is reached. The repetition loop is automatically terminated when  
 an empty string is matched.  
 .P  
 Some workspace is required for remembering the starting position. For most  
 capturing subpatterns, an internal recursive call of the match() function is  
 used, and in this case, the workspace is taken from the runtime stack. However,  
 for non-capturing subpatterns, this is not available. Instead, some fixed  
 workspace (taken from the top-level stack) is used. If it runs out, the  
 PCRE_ERROR_NULLWSLIMIT error is given. The size of the fixed workspace allows  
 for up to 1000 repetitions of a non-capturing subpattern that might match an  
 empty string. If this limit is a problem for you, you can sometimes get round  
 it by changing a non-capturing subpattern into a capturing one, but that will  
 increase the amount of runtime stack that is used.  
 .sp  
1636    PCRE_ERROR_BADNEWLINE     (-23)    PCRE_ERROR_BADNEWLINE     (-23)
1637  .sp  .sp
1638  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
1639  .P  .P
1640  Error numbers -16 to -20 are not used by \fBpcre_exec()\fP.  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
1641  .  .
1642  .  .
1643  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 1638  These functions call \fBpcre_get_stringn Line 1786  These functions call \fBpcre_get_stringn
1786  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1787  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,
1788  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
1789  .  .P
1790    \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple
1791    subpatterns with the same number, you cannot use names to distinguish them,
1792    because names are not included in the compiled code. The matching process uses
1793    only numbers.
1794  .  .
1795  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
1796  .rs  .rs
# Line 1654  example is shown in the Line 1806  example is shown in the
1806  .\" HREF  .\" HREF
1807  \fBpcrepattern\fP  \fBpcrepattern\fP
1808  .\"  .\"
1809  documentation. When duplicates are present, \fBpcre_copy_named_substring()\fP  documentation.
1810  and \fBpcre_get_named_substring()\fP return the first substring corresponding  .P
1811  to the given name that is set. If none are set, an empty string is returned.  When duplicates are present, \fBpcre_copy_named_substring()\fP and
1812  The \fBpcre_get_stringnumber()\fP function returns one of the numbers that are  \fBpcre_get_named_substring()\fP return the first substring corresponding to
1813  associated with the name, but it is not defined which it is.  the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is
1814  .sp  returned; no data is returned. The \fBpcre_get_stringnumber()\fP function
1815    returns one of the numbers that are associated with the name, but it is not
1816    defined which it is.
1817    .P
1818  If you want to get full details of all captured substrings for a given name,  If you want to get full details of all captured substrings for a given name,
1819  you must use the \fBpcre_get_stringtable_entries()\fP function. The first  you must use the \fBpcre_get_stringtable_entries()\fP function. The first
1820  argument is the compiled pattern, and the second is the name. The third and  argument is the compiled pattern, and the second is the name. The third and
# Line 1711  a compiled pattern, using a matching alg Line 1866  a compiled pattern, using a matching alg
1866  just once, and does not backtrack. This has different characteristics to the  just once, and does not backtrack. This has different characteristics to the
1867  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
1868  patterns are not supported. Nevertheless, there are times when this kind of  patterns are not supported. Nevertheless, there are times when this kind of
1869  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
1870  the  list of features that \fBpcre_dfa_exec()\fP does not support, see the
1871  .\" HREF  .\" HREF
1872  \fBpcrematching\fP  \fBpcrematching\fP
1873  .\"  .\"
# Line 1751  Here is an example of a simple call to \ Line 1906  Here is an example of a simple call to \
1906  .sp  .sp
1907  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
1908  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,
1909  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1910  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,
1911  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
1912  .sp  for \fBpcre_exec()\fP, so their description is not repeated here.
1913    PCRE_PARTIAL  .sp
1914  .sp    PCRE_PARTIAL_HARD
1915  This has the same general effect as it does for \fBpcre_exec()\fP, but the    PCRE_PARTIAL_SOFT
1916  details are slightly different. When PCRE_PARTIAL is set for  .sp
1917  \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
1918  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
1919  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
1920  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
1921  matching string.  additional characters. This happens even if some complete matches have also
1922    been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
1923    is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached,
1924    there have been no complete matches, but there is still at least one matching
1925    possibility. The portion of the string that was inspected when the longest
1926    partial match was found is set as the first matching string in both cases.
1927  .sp  .sp
1928    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
1929  .sp  .sp
# Line 1774  matching point in the subject string. Line 1934  matching point in the subject string.
1934  .sp  .sp
1935    PCRE_DFA_RESTART    PCRE_DFA_RESTART
1936  .sp  .sp
1937  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
1938  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
1939  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
1940  option requests this action; when it is set, the \fIworkspace\fP and  \fIworkspace\fP and \fIwscount\fP options must reference the same vector as
1941  \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
1942  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  
1943  .\" HREF  .\" HREF
1944  \fBpcrepartial\fP  \fBpcrepartial\fP
1945  .\"  .\"
# Line 1884  Cambridge CB2 3QH, England. Line 2043  Cambridge CB2 3QH, England.
2043  .rs  .rs
2044  .sp  .sp
2045  .nf  .nf
2046  Last updated: 30 July 2007  Last updated: 26 September 2009
2047  Copyright (c) 1997-2007 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
2048  .fi  .fi

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