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revision 225 by ph10, Mon Aug 20 14:38:34 2007 UTC revision 428 by ph10, Mon Aug 31 17:10:26 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 639  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 647  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 676  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  [this code is not in use]    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 name or an optionally braced    57  \eg is not followed by a braced, angle-bracketed, or quoted
738          non-zero number          name/number or by a plain number
739    58  (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number    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 882  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 option.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
955  .sp  .sp
956    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
957  .sp  .sp
# Line 943  different for each compiled pattern. Line 1008  different for each compiled pattern.
1008    PCRE_INFO_OKPARTIAL    PCRE_INFO_OKPARTIAL
1009  .sp  .sp
1010  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, otherwise 0. The
1011  fourth argument should point to an \fBint\fP variable. The  fourth argument should point to an \fBint\fP variable. From release 8.00, this
1012    always returns 1, because the restrictions that previously applied to partial
1013    matching have been lifted. The
1014  .\" HREF  .\" HREF
1015  \fBpcrepartial\fP  \fBpcrepartial\fP
1016  .\"  .\"
1017  documentation lists the restrictions that apply to patterns when partial  documentation gives details of partial matching.
 matching is used.  
1018  .sp  .sp
1019    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1020  .sp  .sp
# Line 1169  called. See the Line 1235  called. See the
1235  .\"  .\"
1236  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1237  .  .
1238    .\" HTML <a name="execoptions"></a>
1239  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
1240  .rs  .rs
1241  .sp  .sp
1242  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
1243  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,
1244  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_START_OPTIMIZE,
1245    PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and PCRE_PARTIAL_HARD.
1246  .sp  .sp
1247    PCRE_ANCHORED    PCRE_ANCHORED
1248  .sp  .sp
# Line 1183  matching position. If a pattern was comp Line 1251  matching position. If a pattern was comp
1251  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
1252  matching time.  matching time.
1253  .sp  .sp
1254      PCRE_BSR_ANYCRLF
1255      PCRE_BSR_UNICODE
1256    .sp
1257    These options (which are mutually exclusive) control what the \eR escape
1258    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1259    match any Unicode newline sequence. These options override the choice that was
1260    made or defaulted when the pattern was compiled.
1261    .sp
1262    PCRE_NEWLINE_CR    PCRE_NEWLINE_CR
1263    PCRE_NEWLINE_LF    PCRE_NEWLINE_LF
1264    PCRE_NEWLINE_CRLF    PCRE_NEWLINE_CRLF
# Line 1194  the pattern was compiled. For details, s Line 1270  the pattern was compiled. For details, s
1270  \fBpcre_compile()\fP above. During matching, the newline choice affects the  \fBpcre_compile()\fP above. During matching, the newline choice affects the
1271  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1272  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
1273  pattern. When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is  pattern.
1274  set, and a match attempt fails when the current position is at a CRLF sequence,  .P
1275  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
1276  words, to after the CRLF.  match attempt for an unanchored pattern fails when the current position is at a
1277  .P  CRLF sequence, and the pattern contains no explicit matches for CR or LF
1278  Anomalous effects can occur when CRLF is a valid newline sequence and explicit  characters, the match position is advanced by two characters instead of one, in
1279  \er or \en escapes appear in the pattern. For example, the string "\er\enA"  other words, to after the CRLF.
1280  matches the unanchored pattern \enA but not [X\en]A. This happens because, in  .P
1281  the first case, PCRE knows that the match must start with \en, and so it skips  The above rule is a compromise that makes the most common cases work as
1282  there before trying to match. In the second case, it has no knowledge about the  expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1283  starting character, so it starts matching at the beginning of the string, and  set), it does not match the string "\er\enA" because, after failing at the
1284  on failing, skips over the CRLF as described above. However, if the pattern is  start, it skips both the CR and the LF before retrying. However, the pattern
1285  studied, the match succeeds, because then PCRE once again knows where to start.  [\er\en]A does match that string, because it contains an explicit CR or LF
1286    reference, and so advances only by one character after the first failure.
1287    .P
1288    An explicit match for CR of LF is either a literal appearance of one of those
1289    characters, or one of the \er or \en escape sequences. Implicit matches such as
1290    [^X] do not count, nor does \es (which includes CR and LF in the characters
1291    that it matches).
1292    .P
1293    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1294    valid newline sequence and explicit \er or \en escapes appear in the pattern.
1295  .sp  .sp
1296    PCRE_NOTBOL    PCRE_NOTBOL
1297  .sp  .sp
# Line 1244  PCRE_NOTEMPTY and PCRE_ANCHORED, and the Line 1329  PCRE_NOTEMPTY and PCRE_ANCHORED, and the
1329  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
1330  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.
1331  .sp  .sp
1332      PCRE_NO_START_OPTIMIZE
1333    .sp
1334    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1335    a match, in order to speed up the process. For example, if it is known that a
1336    match must start with a specific character, it searches the subject for that
1337    character, and fails immediately if it cannot find it, without actually running
1338    the main matching function. When callouts are in use, these optimizations can
1339    cause them to be skipped. This option disables the "start-up" optimizations,
1340    causing performance to suffer, but ensuring that the callouts do occur.
1341    .sp
1342    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1343  .sp  .sp
1344  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
# Line 1273  PCRE_NO_UTF8_CHECK is set, the effect of Line 1368  PCRE_NO_UTF8_CHECK is set, the effect of
1368  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
1369  UTF-8 character, is undefined. Your program may crash.  UTF-8 character, is undefined. Your program may crash.
1370  .sp  .sp
1371    PCRE_PARTIAL    PCRE_PARTIAL_HARD
1372      PCRE_PARTIAL_SOFT
1373  .sp  .sp
1374  This option turns on the partial matching feature. If the subject string fails  These options turn on the partial matching feature. For backwards
1375  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
1376  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
1377  the failure to match occurred only because there were not enough subject  not enough subject characters to complete the match. If this happens when
1378  characters), \fBpcre_exec()\fP returns PCRE_ERROR_PARTIAL instead of  PCRE_PARTIAL_HARD is set, \fBpcre_exec()\fP immediately returns
1379  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
1380  may appear in the pattern. These are discussed in the  by testing any other alternatives. Only if they all fail is PCRE_ERROR_PARTIAL
1381    returned (instead of PCRE_ERROR_NOMATCH). The portion of the string that
1382    provided the partial match is set as the first matching string. There is a more
1383    detailed discussion in the
1384  .\" HREF  .\" HREF
1385  \fBpcrepartial\fP  \fBpcrepartial\fP
1386  .\"  .\"
# Line 1291  documentation. Line 1390  documentation.
1390  .rs  .rs
1391  .sp  .sp
1392  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
1393  \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
1394  \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
1395  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
1396  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
1397  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.
1398  .P  .P
1399  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
1400  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 1329  pattern. Following the usage in Jeffrey Line 1428  pattern. Following the usage in Jeffrey
1428  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
1429  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1430  .P  .P
1431  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
1432  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
1433  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
1434  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1435  .P  .P
1436  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,
1437  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
1438  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1439  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1440  \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
1441  rounded down.  rounded down.
1442  .P  .P
1443  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1444  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1445  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
1446  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
1447  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
1448  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
1449  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1450  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1451  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
1452  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
1453  capturing subpatterns, the return value from a successful match is 1,  used for the first capturing subpattern, and so on. The value returned by
1454  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.
1455    For example, if two substrings have been captured, the returned value is 3. If
1456    there are no capturing subpatterns, the return value from a successful match is
1457    1, indicating that just the first pair of offsets has been set.
1458  .P  .P
1459  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
1460  string that it matched that is returned.  string that it matched that is returned.
1461  .P  .P
1462  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
1463  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
1464  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,
1465  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
1466  \fIovecsize\fP as zero. However, if the pattern contains back references and  \fIovecsize\fP as zero. However, if the pattern contains back references and
1467  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
1468  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 1471  documentation for details of partial mat Line 1573  documentation for details of partial mat
1573  .sp  .sp
1574    PCRE_ERROR_BADPARTIAL     (-13)    PCRE_ERROR_BADPARTIAL     (-13)
1575  .sp  .sp
1576  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
1577  are not supported for partial matching. See the  option was used with a compiled pattern containing items that were not
1578  .\" HREF  supported for partial matching. From release 8.00 onwards, there are no
1579  \fBpcrepartial\fP  restrictions on partial matching.
 .\"  
 documentation for details of partial matching.  
1580  .sp  .sp
1581    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
1582  .sp  .sp
# Line 1646  These functions call \fBpcre_get_stringn Line 1746  These functions call \fBpcre_get_stringn
1746  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1747  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,
1748  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
1749  .  .P
1750    \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple
1751    subpatterns with the same number, you cannot use names to distinguish them,
1752    because names are not included in the compiled code. The matching process uses
1753    only numbers.
1754  .  .
1755  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
1756  .rs  .rs
# Line 1762  Here is an example of a simple call to \ Line 1866  Here is an example of a simple call to \
1866  .sp  .sp
1867  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
1868  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,
1869  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD,
1870  PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last three of these are  PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last
1871  the same as for \fBpcre_exec()\fP, so their description is not repeated here.  four of these are exactly the same as for \fBpcre_exec()\fP, so their
1872  .sp  description is not repeated here.
1873    PCRE_PARTIAL  .sp
1874  .sp    PCRE_PARTIAL_HARD
1875  This has the same general effect as it does for \fBpcre_exec()\fP, but the    PCRE_PARTIAL_SOFT
1876  details are slightly different. When PCRE_PARTIAL is set for  .sp
1877  \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
1878  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
1879  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
1880  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
1881  matching string.  additional characters. This happens even if some complete matches have also
1882    been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
1883    is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached,
1884    there have been no complete matches, but there is still at least one matching
1885    possibility. The portion of the string that provided the longest partial match
1886    is set as the first matching string in both cases.
1887  .sp  .sp
1888    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
1889  .sp  .sp
# Line 1785  matching point in the subject string. Line 1894  matching point in the subject string.
1894  .sp  .sp
1895    PCRE_DFA_RESTART    PCRE_DFA_RESTART
1896  .sp  .sp
1897  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
1898  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
1899  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
1900  option requests this action; when it is set, the \fIworkspace\fP and  \fIworkspace\fP and \fIwscount\fP options must reference the same vector as
1901  \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
1902  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  
1903  .\" HREF  .\" HREF
1904  \fBpcrepartial\fP  \fBpcrepartial\fP
1905  .\"  .\"
# Line 1895  Cambridge CB2 3QH, England. Line 2003  Cambridge CB2 3QH, England.
2003  .rs  .rs
2004  .sp  .sp
2005  .nf  .nf
2006  Last updated: 20 August 2007  Last updated: 29 August 2009
2007  Copyright (c) 1997-2007 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
2008  .fi  .fi

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