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revision 155 by ph10, Tue Apr 24 13:36:11 2007 UTC revision 389 by ph10, Sun Mar 15 18:24:05 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 303  that is recognized as meaning "newline". Line 320  that is recognized as meaning "newline".
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. The
321  default should normally be the standard sequence for your operating system.  default should normally be the standard sequence for your operating system.
322  .sp  .sp
323      PCRE_CONFIG_BSR
324    .sp
325    The output is an integer whose value indicates what character sequences the \eR
326    escape sequence matches by default. A value of 0 means that \eR matches any
327    Unicode line ending sequence; a value of 1 means that \eR matches only CR, LF,
328    or CRLF. The default can be overridden when a pattern is compiled or matched.
329    .sp
330    PCRE_CONFIG_LINK_SIZE    PCRE_CONFIG_LINK_SIZE
331  .sp  .sp
332  The output is an integer that contains the number of bytes used for internal  The output is an integer that contains the number of bytes used for internal
# Line 323  documentation. Line 347  documentation.
347  .sp  .sp
348    PCRE_CONFIG_MATCH_LIMIT    PCRE_CONFIG_MATCH_LIMIT
349  .sp  .sp
350  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
351  internal matching function calls in a \fBpcre_exec()\fP execution. Further  internal matching function calls in a \fBpcre_exec()\fP execution. Further
352  details are given with \fBpcre_exec()\fP below.  details are given with \fBpcre_exec()\fP below.
353  .sp  .sp
354    PCRE_CONFIG_MATCH_LIMIT_RECURSION    PCRE_CONFIG_MATCH_LIMIT_RECURSION
355  .sp  .sp
356  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
357  recursion when calling the internal matching function in a \fBpcre_exec()\fP  recursion when calling the internal matching function in a \fBpcre_exec()\fP
358  execution. Further details are given with \fBpcre_exec()\fP below.  execution. Further details are given with \fBpcre_exec()\fP below.
359  .sp  .sp
# Line 444  facility, see the Line 468  facility, see the
468  .\"  .\"
469  documentation.  documentation.
470  .sp  .sp
471      PCRE_BSR_ANYCRLF
472      PCRE_BSR_UNICODE
473    .sp
474    These options (which are mutually exclusive) control what the \eR escape
475    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
476    match any Unicode newline sequence. The default is specified when PCRE is
477    built. It can be overridden from within the pattern, or by setting an option
478    when a compiled pattern is matched.
479    .sp
480    PCRE_CASELESS    PCRE_CASELESS
481  .sp  .sp
482  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 549  If this option is set, an unanchored pat
549  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
550  over the newline.  over the newline.
551  .sp  .sp
552      PCRE_JAVASCRIPT_COMPAT
553    .sp
554    If this option is set, PCRE's behaviour is changed in some ways so that it is
555    compatible with JavaScript rather than Perl. The changes are as follows:
556    .P
557    (1) A lone closing square bracket in a pattern causes a compile-time error,
558    because this is illegal in JavaScript (by default it is treated as a data
559    character). Thus, the pattern AB]CD becomes illegal when this option is set.
560    .P
561    (2) At run time, a back reference to an unset subpattern group matches an empty
562    string (by default this causes the current matching alternative to fail). A
563    pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
564    an "a" in the subject), whereas it fails by default, for Perl compatibility.
565    .sp
566    PCRE_MULTILINE    PCRE_MULTILINE
567  .sp  .sp
568  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 648  page.
648    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
649  .sp  .sp
650  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
651  automatically checked. If an invalid UTF-8 sequence of bytes is found,  automatically checked. There is a discussion about the
652  \fBpcre_compile()\fP returns an error. If you already know that your pattern is  .\" HTML <a href="pcre.html#utf8strings">
653  valid, and you want to skip this check for performance reasons, you can set the  .\" </a>
654  PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid  validity of UTF-8 strings
655  UTF-8 string as a pattern is undefined. It may cause your program to crash.  .\"
656  Note that this option can also be passed to \fBpcre_exec()\fP and  in the main
657  \fBpcre_dfa_exec()\fP, to suppress the UTF-8 validity checking of subject  .\" HREF
658  strings.  \fBpcre\fP
659    .\"
660    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_compile()\fP
661    returns an error. If you already know that your pattern is valid, and you want
662    to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
663    option. When it is set, the effect of passing an invalid UTF-8 string as a
664    pattern is undefined. It may cause your program to crash. Note that this option
665    can also be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress
666    the UTF-8 validity checking of subject strings.
667  .  .
668  .  .
669  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 631  out of use. To avoid confusion, they hav Line 686  out of use. To avoid confusion, they hav
686     9  nothing to repeat     9  nothing to repeat
687    10  [this code is not in use]    10  [this code is not in use]
688    11  internal error: unexpected repeat    11  internal error: unexpected repeat
689    12  unrecognized character after (?    12  unrecognized character after (? or (?-
690    13  POSIX named classes are supported only within a class    13  POSIX named classes are supported only within a class
691    14  missing )    14  missing )
692    15  reference to non-existent subpattern    15  reference to non-existent subpattern
# Line 639  out of use. To avoid confusion, they hav Line 694  out of use. To avoid confusion, they hav
694    17  unknown option bit(s) set    17  unknown option bit(s) set
695    18  missing ) after comment    18  missing ) after comment
696    19  [this code is not in use]    19  [this code is not in use]
697    20  regular expression too large    20  regular expression is too large
698    21  failed to get memory    21  failed to get memory
699    22  unmatched parentheses    22  unmatched parentheses
700    23  internal error: code overflow    23  internal error: code overflow
# Line 648  out of use. To avoid confusion, they hav Line 703  out of use. To avoid confusion, they hav
703    26  malformed number or name after (?(    26  malformed number or name after (?(
704    27  conditional group contains more than two branches    27  conditional group contains more than two branches
705    28  assertion expected after (?(    28  assertion expected after (?(
706    29  (?R or (?digits must be followed by )    29  (?R or (?[+-]digits must be followed by )
707    30  unknown POSIX class name    30  unknown POSIX class name
708    31  POSIX collating elements are not supported    31  POSIX collating elements are not supported
709    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 723  out of use. To avoid confusion, they hav
723    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
724    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
725    48  subpattern name is too long (maximum 32 characters)    48  subpattern name is too long (maximum 32 characters)
726    49  too many named subpatterns (maximum 10,000)    49  too many named subpatterns (maximum 10000)
727    50  repeated subpattern is too long    50  [this code is not in use]
728    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 (not in UTF-8 mode)
729    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
730    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern not found
731    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
732    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
733    56  inconsistent NEWLINE options"    56  inconsistent NEWLINE options
734      57  \eg is not followed by a braced, angle-bracketed, or quoted
735            name/number or by a plain number
736      58  a numbered reference must not be zero
737      59  (*VERB) with an argument is not supported
738      60  (*VERB) not recognized
739      61  number is too big
740      62  subpattern name expected
741      63  digit expected after (?+
742      64  ] is an invalid data character in JavaScript compatibility mode
743    .sp
744    The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
745    be used if the limits were changed when PCRE was built.
746  .  .
747  .  .
748  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
# Line 871  table indicating a fixed set of bytes fo Line 938  table indicating a fixed set of bytes fo
938  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
939  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
940  .sp  .sp
941      PCRE_INFO_HASCRORLF
942    .sp
943    Return 1 if the pattern contains any explicit matches for CR or LF characters,
944    otherwise 0. The fourth argument should point to an \fBint\fP variable. An
945    explicit match is either a literal CR or LF character, or \er or \en.
946    .sp
947      PCRE_INFO_JCHANGED
948    .sp
949    Return 1 if the (?J) or (?-J) option setting is used in the pattern, otherwise
950    0. The fourth argument should point to an \fBint\fP variable. (?J) and
951    (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
952    .sp
953    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
954  .sp  .sp
955  Return the value of the rightmost literal byte that must exist in any matched  Return the value of the rightmost literal byte that must exist in any matched
# Line 923  When writing code to extract data from n Line 1002  When writing code to extract data from n
1002  name-to-number map, remember that the length of the entries is likely to be  name-to-number map, remember that the length of the entries is likely to be
1003  different for each compiled pattern.  different for each compiled pattern.
1004  .sp  .sp
1005      PCRE_INFO_OKPARTIAL
1006    .sp
1007    Return 1 if the pattern can be used for partial matching, otherwise 0. The
1008    fourth argument should point to an \fBint\fP variable. The
1009    .\" HREF
1010    \fBpcrepartial\fP
1011    .\"
1012    documentation lists the restrictions that apply to patterns when partial
1013    matching is used.
1014    .sp
1015    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1016  .sp  .sp
1017  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
1018  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
1019  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
1020  top-level option settings within the pattern itself.  top-level option settings at the start of the pattern itself. In other words,
1021    they are the options that will be in force when matching starts. For example,
1022    if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the
1023    result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED.
1024  .P  .P
1025  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
1026  alternatives begin with one of the following:  alternatives begin with one of the following:
# Line 1139  called. See the Line 1231  called. See the
1231  .\"  .\"
1232  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1233  .  .
1234    .\" HTML <a name="execoptions"></a>
1235  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
1236  .rs  .rs
1237  .sp  .sp
1238  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
1239  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,
1240  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_START_OPTIMIZE,
1241    PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.
1242  .sp  .sp
1243    PCRE_ANCHORED    PCRE_ANCHORED
1244  .sp  .sp
# Line 1153  matching position. If a pattern was comp Line 1247  matching position. If a pattern was comp
1247  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
1248  matching time.  matching time.
1249  .sp  .sp
1250      PCRE_BSR_ANYCRLF
1251      PCRE_BSR_UNICODE
1252    .sp
1253    These options (which are mutually exclusive) control what the \eR escape
1254    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1255    match any Unicode newline sequence. These options override the choice that was
1256    made or defaulted when the pattern was compiled.
1257    .sp
1258    PCRE_NEWLINE_CR    PCRE_NEWLINE_CR
1259    PCRE_NEWLINE_LF    PCRE_NEWLINE_LF
1260    PCRE_NEWLINE_CRLF    PCRE_NEWLINE_CRLF
# Line 1164  the pattern was compiled. For details, s Line 1266  the pattern was compiled. For details, s
1266  \fBpcre_compile()\fP above. During matching, the newline choice affects the  \fBpcre_compile()\fP above. During matching, the newline choice affects the
1267  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1268  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
1269  pattern. When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is  pattern.
1270  set, and a match attempt fails when the current position is at a CRLF sequence,  .P
1271  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
1272  words, to after the CRLF.  match attempt for an unanchored pattern fails when the current position is at a
1273    CRLF sequence, and the pattern contains no explicit matches for CR or LF
1274    characters, the match position is advanced by two characters instead of one, in
1275    other words, to after the CRLF.
1276    .P
1277    The above rule is a compromise that makes the most common cases work as
1278    expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1279    set), it does not match the string "\er\enA" because, after failing at the
1280    start, it skips both the CR and the LF before retrying. However, the pattern
1281    [\er\en]A does match that string, because it contains an explicit CR or LF
1282    reference, and so advances only by one character after the first failure.
1283    .P
1284    An explicit match for CR of LF is either a literal appearance of one of those
1285    characters, or one of the \er or \en escape sequences. Implicit matches such as
1286    [^X] do not count, nor does \es (which includes CR and LF in the characters
1287    that it matches).
1288    .P
1289    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1290    valid newline sequence and explicit \er or \en escapes appear in the pattern.
1291  .sp  .sp
1292    PCRE_NOTBOL    PCRE_NOTBOL
1293  .sp  .sp
# Line 1205  PCRE_NOTEMPTY and PCRE_ANCHORED, and the Line 1325  PCRE_NOTEMPTY and PCRE_ANCHORED, and the
1325  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
1326  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.
1327  .sp  .sp
1328      PCRE_NO_START_OPTIMIZE
1329    .sp
1330    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1331    a match, in order to speed up the process. For example, if it is known that a
1332    match must start with a specific character, it searches the subject for that
1333    character, and fails immediately if it cannot find it, without actually running
1334    the main matching function. When callouts are in use, these optimizations can
1335    cause them to be skipped. This option disables the "start-up" optimizations,
1336    causing performance to suffer, but ensuring that the callouts do occur.
1337    .sp
1338    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1339  .sp  .sp
1340  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
1341  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1342  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
1343  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
1344  \fBpcre_exec()\fP returns the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP  strings in the
1345  contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.  .\" HTML <a href="pcre.html#utf8strings">
1346    .\" </a>
1347    section on UTF-8 support
1348    .\"
1349    in the main
1350    .\" HREF
1351    \fBpcre\fP
1352    .\"
1353    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1354    the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains an invalid value,
1355    PCRE_ERROR_BADUTF8_OFFSET is returned.
1356  .P  .P
1357  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
1358  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 1242  documentation. Line 1382  documentation.
1382  .rs  .rs
1383  .sp  .sp
1384  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
1385  \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
1386  \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
1387  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
1388  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
1389  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.
1390  .P  .P
1391  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
1392  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 1280  pattern. Following the usage in Jeffrey Line 1420  pattern. Following the usage in Jeffrey
1420  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
1421  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1422  .P  .P
1423  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
1424  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
1425  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
1426  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1427  .P  .P
1428  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,
1429  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
1430  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1431  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1432  \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
1433  rounded down.  rounded down.
1434  .P  .P
1435  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1436  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1437  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
1438  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
1439  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
1440  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
1441  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1442  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1443  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
1444  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
1445  capturing subpatterns, the return value from a successful match is 1,  used for the first capturing subpattern, and so on. The value returned by
1446  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.
1447    For example, if two substrings have been captured, the returned value is 3. If
1448    there are no capturing subpatterns, the return value from a successful match is
1449    1, indicating that just the first pair of offsets has been set.
1450  .P  .P
1451  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
1452  string that it matched that is returned.  string that it matched that is returned.
1453  .P  .P
1454  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
1455  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
1456  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,
1457  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
1458  \fIovecsize\fP as zero. However, if the pattern contains back references and  \fIovecsize\fP as zero. However, if the pattern contains back references and
1459  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
1460  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  The internal recursion limit, as specifi Line 1587  The internal recursion limit, as specifi
1587  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
1588  description above.  description above.
1589  .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  
1590    PCRE_ERROR_BADNEWLINE     (-23)    PCRE_ERROR_BADNEWLINE     (-23)
1591  .sp  .sp
1592  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
1593  .P  .P
1594  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.
1595  .  .
1596  .  .
1597  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 1605  These functions call \fBpcre_get_stringn Line 1740  These functions call \fBpcre_get_stringn
1740  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1741  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,
1742  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
1743  .  .P
1744    \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple
1745    subpatterns with the same number, you cannot use names to distinguish them,
1746    because names are not included in the compiled code. The matching process uses
1747    only numbers.
1748  .  .
1749  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
1750  .rs  .rs
# Line 1621  example is shown in the Line 1760  example is shown in the
1760  .\" HREF  .\" HREF
1761  \fBpcrepattern\fP  \fBpcrepattern\fP
1762  .\"  .\"
1763  documentation. When duplicates are present, \fBpcre_copy_named_substring()\fP  documentation.
1764  and \fBpcre_get_named_substring()\fP return the first substring corresponding  .P
1765  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
1766  The \fBpcre_get_stringnumber()\fP function returns one of the numbers that are  \fBpcre_get_named_substring()\fP return the first substring corresponding to
1767  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
1768  .sp  returned; no data is returned. The \fBpcre_get_stringnumber()\fP function
1769    returns one of the numbers that are associated with the name, but it is not
1770    defined which it is.
1771    .P
1772  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,
1773  you must use the \fBpcre_get_stringtable_entries()\fP function. The first  you must use the \fBpcre_get_stringtable_entries()\fP function. The first
1774  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 1851  Cambridge CB2 3QH, England. Line 1993  Cambridge CB2 3QH, England.
1993  .rs  .rs
1994  .sp  .sp
1995  .nf  .nf
1996  Last updated: 24 April 2007  Last updated: 15 March 2009
1997  Copyright (c) 1997-2007 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
1998  .fi  .fi

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