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revision 172 by ph10, Tue Jun 5 10:40:13 2007 UTC revision 412 by ph10, Sat Apr 11 10:34:37 2009 UTC
# Line 140  distribution. The Line 140  distribution. The
140  .\" HREF  .\" HREF
141  \fBpcresample\fP  \fBpcresample\fP
142  .\"  .\"
143  documentation describes how to run it.  documentation describes how to compile and run it.
144  .P  .P
145  A second matching function, \fBpcre_dfa_exec()\fP, which is not  A second matching function, \fBpcre_dfa_exec()\fP, which is not
146  Perl-compatible, is also provided. This uses a different algorithm for the  Perl-compatible, is also provided. This uses a different algorithm for the
# Line 218  points during a matching operation. Deta Line 218  points during a matching operation. Deta
218  documentation.  documentation.
219  .  .
220  .  .
221    .\" HTML <a name="newlines"></a>
222  .SH NEWLINES  .SH NEWLINES
223  .rs  .rs
224  .sp  .sp
# Line 235  The default default is LF, which is the Line 236  The default default is LF, which is the
236  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
237  matched.  matched.
238  .P  .P
239    At compile time, the newline convention can be specified by the \fIoptions\fP
240    argument of \fBpcre_compile()\fP, or it can be specified by special text at the
241    start of the pattern itself; this overrides any other settings. See the
242    .\" HREF
243    \fBpcrepattern\fP
244    .\"
245    page for details of the special character sequences.
246    .P
247  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
248  pair of characters that indicate a line break". The choice of newline  pair of characters that indicate a line break". The choice of newline
249  convention affects the handling of the dot, circumflex, and dollar  convention affects the handling of the dot, circumflex, and dollar
250  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
251  recognized line ending sequence, the match position advancement for a  recognized line ending sequence, the match position advancement for a
252  non-anchored pattern. The choice of newline convention does not affect the  non-anchored pattern. There is more detail about this in the
253  interpretation of the \en or \er escape sequences.  .\" HTML <a href="#execoptions">
254    .\" </a>
255    section on \fBpcre_exec()\fP options
256    .\"
257    below.
258    .P
259    The choice of newline convention does not affect the interpretation of
260    the \en or \er escape sequences, nor does it affect what \eR matches, which is
261    controlled in a similar way, but by separate options.
262  .  .
263  .  .
264  .SH MULTITHREADING  .SH MULTITHREADING
# Line 300  properties is available; otherwise it is Line 317  properties is available; otherwise it is
317  .sp  .sp
318  The output is an integer whose value specifies the default character sequence  The output is an integer whose value specifies the default character sequence
319  that is recognized as meaning "newline". The four values that are supported  that is recognized as meaning "newline". The four values that are supported
320  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.
321  default should normally be the standard sequence for your operating system.  Though they are derived from ASCII, the same values are returned in EBCDIC
322    environments. The default should normally correspond to the standard sequence
323    for your operating system.
324    .sp
325      PCRE_CONFIG_BSR
326    .sp
327    The output is an integer whose value indicates what character sequences the \eR
328    escape sequence matches by default. A value of 0 means that \eR matches any
329    Unicode line ending sequence; a value of 1 means that \eR matches only CR, LF,
330    or CRLF. The default can be overridden when a pattern is compiled or matched.
331  .sp  .sp
332    PCRE_CONFIG_LINK_SIZE    PCRE_CONFIG_LINK_SIZE
333  .sp  .sp
# Line 323  documentation. Line 349  documentation.
349  .sp  .sp
350    PCRE_CONFIG_MATCH_LIMIT    PCRE_CONFIG_MATCH_LIMIT
351  .sp  .sp
352  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
353  internal matching function calls in a \fBpcre_exec()\fP execution. Further  internal matching function calls in a \fBpcre_exec()\fP execution. Further
354  details are given with \fBpcre_exec()\fP below.  details are given with \fBpcre_exec()\fP below.
355  .sp  .sp
356    PCRE_CONFIG_MATCH_LIMIT_RECURSION    PCRE_CONFIG_MATCH_LIMIT_RECURSION
357  .sp  .sp
358  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
359  recursion when calling the internal matching function in a \fBpcre_exec()\fP  recursion when calling the internal matching function in a \fBpcre_exec()\fP
360  execution. Further details are given with \fBpcre_exec()\fP below.  execution. Further details are given with \fBpcre_exec()\fP below.
361  .sp  .sp
# Line 380  argument, which is an address (see below Line 406  argument, which is an address (see below
406  .P  .P
407  The \fIoptions\fP argument contains various bit settings that affect the  The \fIoptions\fP argument contains various bit settings that affect the
408  compilation. It should be zero if no options are required. The available  compilation. It should be zero if no options are required. The available
409  options are described below. Some of them, in particular, those that are  options are described below. Some of them (in particular, those that are
410  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
411  the detailed description in the  within the pattern (see the detailed description in the
412  .\" HREF  .\" HREF
413  \fBpcrepattern\fP  \fBpcrepattern\fP
414  .\"  .\"
415  documentation). For these options, the contents of the \fIoptions\fP argument  documentation). For those options that can be different in different parts of
416  specifies their initial settings at the start of compilation and execution. The  the pattern, the contents of the \fIoptions\fP argument specifies their initial
417  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
418  matching as well as at compile time.  PCRE_NEWLINE_\fIxxx\fP options can be set at the time of matching as well as at
419    compile time.
420  .P  .P
421  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
422  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
# Line 444  facility, see the Line 471  facility, see the
471  .\"  .\"
472  documentation.  documentation.
473  .sp  .sp
474      PCRE_BSR_ANYCRLF
475      PCRE_BSR_UNICODE
476    .sp
477    These options (which are mutually exclusive) control what the \eR escape
478    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
479    match any Unicode newline sequence. The default is specified when PCRE is
480    built. It can be overridden from within the pattern, or by setting an option
481    when a compiled pattern is matched.
482    .sp
483    PCRE_CASELESS    PCRE_CASELESS
484  .sp  .sp
485  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 552  If this option is set, an unanchored pat
552  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
553  over the newline.  over the newline.
554  .sp  .sp
555      PCRE_JAVASCRIPT_COMPAT
556    .sp
557    If this option is set, PCRE's behaviour is changed in some ways so that it is
558    compatible with JavaScript rather than Perl. The changes are as follows:
559    .P
560    (1) A lone closing square bracket in a pattern causes a compile-time error,
561    because this is illegal in JavaScript (by default it is treated as a data
562    character). Thus, the pattern AB]CD becomes illegal when this option is set.
563    .P
564    (2) At run time, a back reference to an unset subpattern group matches an empty
565    string (by default this causes the current matching alternative to fail). A
566    pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
567    an "a" in the subject), whereas it fails by default, for Perl compatibility.
568    .sp
569    PCRE_MULTILINE    PCRE_MULTILINE
570  .sp  .sp
571  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 651  page.
651    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
652  .sp  .sp
653  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
654  automatically checked. If an invalid UTF-8 sequence of bytes is found,  automatically checked. There is a discussion about the
655  \fBpcre_compile()\fP returns an error. If you already know that your pattern is  .\" HTML <a href="pcre.html#utf8strings">
656  valid, and you want to skip this check for performance reasons, you can set the  .\" </a>
657  PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid  validity of UTF-8 strings
658  UTF-8 string as a pattern is undefined. It may cause your program to crash.  .\"
659  Note that this option can also be passed to \fBpcre_exec()\fP and  in the main
660  \fBpcre_dfa_exec()\fP, to suppress the UTF-8 validity checking of subject  .\" HREF
661  strings.  \fBpcre\fP
662    .\"
663    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_compile()\fP
664    returns an error. If you already know that your pattern is valid, and you want
665    to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
666    option. When it is set, the effect of passing an invalid UTF-8 string as a
667    pattern is undefined. It may cause your program to crash. Note that this option
668    can also be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress
669    the UTF-8 validity checking of subject strings.
670  .  .
671  .  .
672  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 631  out of use. To avoid confusion, they hav Line 689  out of use. To avoid confusion, they hav
689     9  nothing to repeat     9  nothing to repeat
690    10  [this code is not in use]    10  [this code is not in use]
691    11  internal error: unexpected repeat    11  internal error: unexpected repeat
692    12  unrecognized character after (?    12  unrecognized character after (? or (?-
693    13  POSIX named classes are supported only within a class    13  POSIX named classes are supported only within a class
694    14  missing )    14  missing )
695    15  reference to non-existent subpattern    15  reference to non-existent subpattern
# Line 639  out of use. To avoid confusion, they hav Line 697  out of use. To avoid confusion, they hav
697    17  unknown option bit(s) set    17  unknown option bit(s) set
698    18  missing ) after comment    18  missing ) after comment
699    19  [this code is not in use]    19  [this code is not in use]
700    20  regular expression too large    20  regular expression is too large
701    21  failed to get memory    21  failed to get memory
702    22  unmatched parentheses    22  unmatched parentheses
703    23  internal error: code overflow    23  internal error: code overflow
# Line 648  out of use. To avoid confusion, they hav Line 706  out of use. To avoid confusion, they hav
706    26  malformed number or name after (?(    26  malformed number or name after (?(
707    27  conditional group contains more than two branches    27  conditional group contains more than two branches
708    28  assertion expected after (?(    28  assertion expected after (?(
709    29  (?R or (?digits must be followed by )    29  (?R or (?[+-]digits must be followed by )
710    30  unknown POSIX class name    30  unknown POSIX class name
711    31  POSIX collating elements are not supported    31  POSIX collating elements are not supported
712    32  this version of PCRE is not compiled with PCRE_UTF8 support    32  this version of PCRE is not compiled with PCRE_UTF8 support
# Line 668  out of use. To avoid confusion, they hav Line 726  out of use. To avoid confusion, they hav
726    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
727    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
728    48  subpattern name is too long (maximum 32 characters)    48  subpattern name is too long (maximum 32 characters)
729    49  too many named subpatterns (maximum 10,000)    49  too many named subpatterns (maximum 10000)
730    50  repeated subpattern is too long    50  [this code is not in use]
731    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 (not in UTF-8 mode)
732    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
733    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern not found
734    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
735    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
736    56  inconsistent NEWLINE options"    56  inconsistent NEWLINE options
737      57  \eg is not followed by a braced, angle-bracketed, or quoted
738            name/number or by a plain number
739      58  a numbered reference must not be zero
740      59  (*VERB) with an argument is not supported
741      60  (*VERB) not recognized
742      61  number is too big
743      62  subpattern name expected
744      63  digit expected after (?+
745      64  ] is an invalid data character in JavaScript compatibility mode
746    .sp
747    The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
748    be used if the limits were changed when PCRE was built.
749  .  .
750  .  .
751  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
# Line 871  table indicating a fixed set of bytes fo Line 941  table indicating a fixed set of bytes fo
941  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
942  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
943  .sp  .sp
944      PCRE_INFO_HASCRORLF
945    .sp
946    Return 1 if the pattern contains any explicit matches for CR or LF characters,
947    otherwise 0. The fourth argument should point to an \fBint\fP variable. An
948    explicit match is either a literal CR or LF character, or \er or \en.
949    .sp
950    PCRE_INFO_JCHANGED    PCRE_INFO_JCHANGED
951  .sp  .sp
952  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
953  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
954  setting changes the local PCRE_DUPNAMES value.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
955  .sp  .sp
956    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
957  .sp  .sp
# Line 944  matching is used. Line 1020  matching is used.
1020  Return a copy of the options with which the pattern was compiled. The fourth  Return a copy of the options with which the pattern was compiled. The fourth
1021  argument should point to an \fBunsigned long int\fP variable. These option bits  argument should point to an \fBunsigned long int\fP variable. These option bits
1022  are those specified in the call to \fBpcre_compile()\fP, modified by any  are those specified in the call to \fBpcre_compile()\fP, modified by any
1023  top-level option settings within the pattern itself.  top-level option settings at the start of the pattern itself. In other words,
1024    they are the options that will be in force when matching starts. For example,
1025    if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the
1026    result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED.
1027  .P  .P
1028  A pattern is automatically anchored by PCRE if all of its top-level  A pattern is automatically anchored by PCRE if all of its top-level
1029  alternatives begin with one of the following:  alternatives begin with one of the following:
# Line 1155  called. See the Line 1234  called. See the
1234  .\"  .\"
1235  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1236  .  .
1237    .\" HTML <a name="execoptions"></a>
1238  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
1239  .rs  .rs
1240  .sp  .sp
1241  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
1242  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,
1243  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_START_OPTIMIZE,
1244    PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.
1245  .sp  .sp
1246    PCRE_ANCHORED    PCRE_ANCHORED
1247  .sp  .sp
# Line 1169  matching position. If a pattern was comp Line 1250  matching position. If a pattern was comp
1250  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
1251  matching time.  matching time.
1252  .sp  .sp
1253      PCRE_BSR_ANYCRLF
1254      PCRE_BSR_UNICODE
1255    .sp
1256    These options (which are mutually exclusive) control what the \eR escape
1257    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1258    match any Unicode newline sequence. These options override the choice that was
1259    made or defaulted when the pattern was compiled.
1260    .sp
1261    PCRE_NEWLINE_CR    PCRE_NEWLINE_CR
1262    PCRE_NEWLINE_LF    PCRE_NEWLINE_LF
1263    PCRE_NEWLINE_CRLF    PCRE_NEWLINE_CRLF
# Line 1180  the pattern was compiled. For details, s Line 1269  the pattern was compiled. For details, s
1269  \fBpcre_compile()\fP above. During matching, the newline choice affects the  \fBpcre_compile()\fP above. During matching, the newline choice affects the
1270  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1271  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
1272  pattern. When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is  pattern.
1273  set, and a match attempt fails when the current position is at a CRLF sequence,  .P
1274  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
1275  words, to after the CRLF.  match attempt for an unanchored pattern fails when the current position is at a
1276    CRLF sequence, and the pattern contains no explicit matches for CR or LF
1277    characters, the match position is advanced by two characters instead of one, in
1278    other words, to after the CRLF.
1279    .P
1280    The above rule is a compromise that makes the most common cases work as
1281    expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1282    set), it does not match the string "\er\enA" because, after failing at the
1283    start, it skips both the CR and the LF before retrying. However, the pattern
1284    [\er\en]A does match that string, because it contains an explicit CR or LF
1285    reference, and so advances only by one character after the first failure.
1286    .P
1287    An explicit match for CR of LF is either a literal appearance of one of those
1288    characters, or one of the \er or \en escape sequences. Implicit matches such as
1289    [^X] do not count, nor does \es (which includes CR and LF in the characters
1290    that it matches).
1291    .P
1292    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1293    valid newline sequence and explicit \er or \en escapes appear in the pattern.
1294  .sp  .sp
1295    PCRE_NOTBOL    PCRE_NOTBOL
1296  .sp  .sp
# Line 1221  PCRE_NOTEMPTY and PCRE_ANCHORED, and the Line 1328  PCRE_NOTEMPTY and PCRE_ANCHORED, and the
1328  starting offset (see below) and trying an ordinary match again. There is some  starting offset (see below) and trying an ordinary match again. There is some
1329  code that demonstrates how to do this in the \fIpcredemo.c\fP sample program.  code that demonstrates how to do this in the \fIpcredemo.c\fP sample program.
1330  .sp  .sp
1331      PCRE_NO_START_OPTIMIZE
1332    .sp
1333    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1334    a match, in order to speed up the process. For example, if it is known that a
1335    match must start with a specific character, it searches the subject for that
1336    character, and fails immediately if it cannot find it, without actually running
1337    the main matching function. When callouts are in use, these optimizations can
1338    cause them to be skipped. This option disables the "start-up" optimizations,
1339    causing performance to suffer, but ensuring that the callouts do occur.
1340    .sp
1341    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1342  .sp  .sp
1343  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
1344  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1345  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
1346  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
1347  \fBpcre_exec()\fP returns the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP  strings in the
1348  contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.  .\" HTML <a href="pcre.html#utf8strings">
1349    .\" </a>
1350    section on UTF-8 support
1351    .\"
1352    in the main
1353    .\" HREF
1354    \fBpcre\fP
1355    .\"
1356    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1357    the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains an invalid value,
1358    PCRE_ERROR_BADUTF8_OFFSET is returned.
1359  .P  .P
1360  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
1361  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 1258  documentation. Line 1385  documentation.
1385  .rs  .rs
1386  .sp  .sp
1387  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
1388  \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
1389  \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
1390  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
1391  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
1392  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.
1393  .P  .P
1394  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
1395  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 1296  pattern. Following the usage in Jeffrey Line 1423  pattern. Following the usage in Jeffrey
1423  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
1424  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1425  .P  .P
1426  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
1427  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
1428  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
1429  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1430  .P  .P
1431  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,
1432  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
1433  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1434  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1435  \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
1436  rounded down.  rounded down.
1437  .P  .P
1438  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1439  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1440  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
1441  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
1442  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
1443  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
1444  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1445  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1446  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
1447  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
1448  capturing subpatterns, the return value from a successful match is 1,  used for the first capturing subpattern, and so on. The value returned by
1449  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.
1450    For example, if two substrings have been captured, the returned value is 3. If
1451    there are no capturing subpatterns, the return value from a successful match is
1452    1, indicating that just the first pair of offsets has been set.
1453  .P  .P
1454  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
1455  string that it matched that is returned.  string that it matched that is returned.
1456  .P  .P
1457  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
1458  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
1459  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,
1460  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
1461  \fIovecsize\fP as zero. However, if the pattern contains back references and  \fIovecsize\fP as zero. However, if the pattern contains back references and
1462  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
1463  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 1460  The internal recursion limit, as specifi Line 1590  The internal recursion limit, as specifi
1590  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
1591  description above.  description above.
1592  .sp  .sp
   PCRE_ERROR_NULLWSLIMIT    (-22)  
 .sp  
 When a group 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. Some workspace is required for this; if it runs out, this error is  
 given.  
 .sp  
1593    PCRE_ERROR_BADNEWLINE     (-23)    PCRE_ERROR_BADNEWLINE     (-23)
1594  .sp  .sp
1595  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
1596  .P  .P
1597  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.
1598  .  .
1599  .  .
1600  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 1621  These functions call \fBpcre_get_stringn Line 1743  These functions call \fBpcre_get_stringn
1743  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1744  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,
1745  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
1746  .  .P
1747    \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple
1748    subpatterns with the same number, you cannot use names to distinguish them,
1749    because names are not included in the compiled code. The matching process uses
1750    only numbers.
1751  .  .
1752  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
1753  .rs  .rs
# Line 1637  example is shown in the Line 1763  example is shown in the
1763  .\" HREF  .\" HREF
1764  \fBpcrepattern\fP  \fBpcrepattern\fP
1765  .\"  .\"
1766  documentation. When duplicates are present, \fBpcre_copy_named_substring()\fP  documentation.
1767  and \fBpcre_get_named_substring()\fP return the first substring corresponding  .P
1768  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
1769  The \fBpcre_get_stringnumber()\fP function returns one of the numbers that are  \fBpcre_get_named_substring()\fP return the first substring corresponding to
1770  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
1771  .sp  returned; no data is returned. The \fBpcre_get_stringnumber()\fP function
1772    returns one of the numbers that are associated with the name, but it is not
1773    defined which it is.
1774    .P
1775  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,
1776  you must use the \fBpcre_get_stringtable_entries()\fP function. The first  you must use the \fBpcre_get_stringtable_entries()\fP function. The first
1777  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 1867  Cambridge CB2 3QH, England. Line 1996  Cambridge CB2 3QH, England.
1996  .rs  .rs
1997  .sp  .sp
1998  .nf  .nf
1999  Last updated: 04 June 2007  Last updated: 11 April 2009
2000  Copyright (c) 1997-2007 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
2001  .fi  .fi

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