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revision 230 by ph10, Mon Sep 10 13:23:56 2007 UTC revision 392 by ph10, Tue Mar 17 21:30:30 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 254  non-anchored pattern. There is more deta Line 254  non-anchored pattern. There is more deta
254  .\" </a>  .\" </a>
255  section on \fBpcre_exec()\fP options  section on \fBpcre_exec()\fP options
256  .\"  .\"
257  below. The choice of newline convention does not affect the interpretation of  below.
258  the \en or \er escape sequences.  .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 314  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 337  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 458  facility, see the Line 470  facility, see the
470  .\"  .\"
471  documentation.  documentation.
472  .sp  .sp
473      PCRE_BSR_ANYCRLF
474      PCRE_BSR_UNICODE
475    .sp
476    These options (which are mutually exclusive) control what the \eR escape
477    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
478    match any Unicode newline sequence. The default is specified when PCRE is
479    built. It can be overridden from within the pattern, or by setting an option
480    when a compiled pattern is matched.
481    .sp
482    PCRE_CASELESS    PCRE_CASELESS
483  .sp  .sp
484  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 530  If this option is set, an unanchored pat Line 551  If this option is set, an unanchored pat
551  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
552  over the newline.  over the newline.
553  .sp  .sp
554      PCRE_JAVASCRIPT_COMPAT
555    .sp
556    If this option is set, PCRE's behaviour is changed in some ways so that it is
557    compatible with JavaScript rather than Perl. The changes are as follows:
558    .P
559    (1) A lone closing square bracket in a pattern causes a compile-time error,
560    because this is illegal in JavaScript (by default it is treated as a data
561    character). Thus, the pattern AB]CD becomes illegal when this option is set.
562    .P
563    (2) At run time, a back reference to an unset subpattern group matches an empty
564    string (by default this causes the current matching alternative to fail). A
565    pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
566    an "a" in the subject), whereas it fails by default, for Perl compatibility.
567    .sp
568    PCRE_MULTILINE    PCRE_MULTILINE
569  .sp  .sp
570  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 653  out of use. To avoid confusion, they hav Line 688  out of use. To avoid confusion, they hav
688     9  nothing to repeat     9  nothing to repeat
689    10  [this code is not in use]    10  [this code is not in use]
690    11  internal error: unexpected repeat    11  internal error: unexpected repeat
691    12  unrecognized character after (?    12  unrecognized character after (? or (?-
692    13  POSIX named classes are supported only within a class    13  POSIX named classes are supported only within a class
693    14  missing )    14  missing )
694    15  reference to non-existent subpattern    15  reference to non-existent subpattern
# Line 661  out of use. To avoid confusion, they hav Line 696  out of use. To avoid confusion, they hav
696    17  unknown option bit(s) set    17  unknown option bit(s) set
697    18  missing ) after comment    18  missing ) after comment
698    19  [this code is not in use]    19  [this code is not in use]
699    20  regular expression too large    20  regular expression is too large
700    21  failed to get memory    21  failed to get memory
701    22  unmatched parentheses    22  unmatched parentheses
702    23  internal error: code overflow    23  internal error: code overflow
# Line 690  out of use. To avoid confusion, they hav Line 725  out of use. To avoid confusion, they hav
725    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
726    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
727    48  subpattern name is too long (maximum 32 characters)    48  subpattern name is too long (maximum 32 characters)
728    49  too many named subpatterns (maximum 10,000)    49  too many named subpatterns (maximum 10000)
729    50  [this code is not in use]    50  [this code is not in use]
730    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 (not in UTF-8 mode)
731    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
732    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern not found
733    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
734    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
735    56  inconsistent NEWLINE options"    56  inconsistent NEWLINE options
736    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
737          non-zero number          name/number or by a plain number
738    58  (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number    58  a numbered reference must not be zero
739      59  (*VERB) with an argument is not supported
740      60  (*VERB) not recognized
741      61  number is too big
742      62  subpattern name expected
743      63  digit expected after (?+
744      64  ] is an invalid data character in JavaScript compatibility mode
745    .sp
746    The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
747    be used if the limits were changed when PCRE was built.
748  .  .
749  .  .
750  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
# Line 899  fourth argument should point to an \fBun Line 943  fourth argument should point to an \fBun
943    PCRE_INFO_HASCRORLF    PCRE_INFO_HASCRORLF
944  .sp  .sp
945  Return 1 if the pattern contains any explicit matches for CR or LF characters,  Return 1 if the pattern contains any explicit matches for CR or LF characters,
946  otherwise 0. The fourth argument should point to an \fBint\fP variable.  otherwise 0. The fourth argument should point to an \fBint\fP variable. An
947    explicit match is either a literal CR or LF character, or \er or \en.
948  .sp  .sp
949    PCRE_INFO_JCHANGED    PCRE_INFO_JCHANGED
950  .sp  .sp
951  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
952  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
953  setting changes the local PCRE_DUPNAMES option.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
954  .sp  .sp
955    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
956  .sp  .sp
# Line 1194  documentation for a discussion of saving Line 1239  documentation for a discussion of saving
1239  .sp  .sp
1240  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
1241  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,
1242  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_START_OPTIMIZE,
1243    PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.
1244  .sp  .sp
1245    PCRE_ANCHORED    PCRE_ANCHORED
1246  .sp  .sp
# Line 1203  matching position. If a pattern was comp Line 1249  matching position. If a pattern was comp
1249  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
1250  matching time.  matching time.
1251  .sp  .sp
1252      PCRE_BSR_ANYCRLF
1253      PCRE_BSR_UNICODE
1254    .sp
1255    These options (which are mutually exclusive) control what the \eR escape
1256    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1257    match any Unicode newline sequence. These options override the choice that was
1258    made or defaulted when the pattern was compiled.
1259    .sp
1260    PCRE_NEWLINE_CR    PCRE_NEWLINE_CR
1261    PCRE_NEWLINE_LF    PCRE_NEWLINE_LF
1262    PCRE_NEWLINE_CRLF    PCRE_NEWLINE_CRLF
# Line 1229  start, it skips both the CR and the LF b Line 1283  start, it skips both the CR and the LF b
1283  [\er\en]A does match that string, because it contains an explicit CR or LF  [\er\en]A does match that string, because it contains an explicit CR or LF
1284  reference, and so advances only by one character after the first failure.  reference, and so advances only by one character after the first failure.
1285  .P  .P
1286  An explicit match for CR of LF is either a literal appearance of one of those  An explicit match for CR of LF is either a literal appearance of one of those
1287  characters, or one of the \er or \en escape sequences. Implicit matches such as  characters, or one of the \er or \en escape sequences. Implicit matches such as
1288  [^X] do not count, nor does \es (which includes CR and LF in the characters  [^X] do not count, nor does \es (which includes CR and LF in the characters
1289  that it matches).  that it matches).
1290  .P  .P
# Line 1273  PCRE_NOTEMPTY and PCRE_ANCHORED, and the Line 1327  PCRE_NOTEMPTY and PCRE_ANCHORED, and the
1327  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
1328  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.
1329  .sp  .sp
1330      PCRE_NO_START_OPTIMIZE
1331    .sp
1332    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1333    a match, in order to speed up the process. For example, if it is known that a
1334    match must start with a specific character, it searches the subject for that
1335    character, and fails immediately if it cannot find it, without actually running
1336    the main matching function. When callouts are in use, these optimizations can
1337    cause them to be skipped. This option disables the "start-up" optimizations,
1338    causing performance to suffer, but ensuring that the callouts do occur.
1339    .sp
1340    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1341  .sp  .sp
1342  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 1320  documentation. Line 1384  documentation.
1384  .rs  .rs
1385  .sp  .sp
1386  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
1387  \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
1388  \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
1389  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
1390  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
1391  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.
1392  .P  .P
1393  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
1394  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 1358  pattern. Following the usage in Jeffrey Line 1422  pattern. Following the usage in Jeffrey
1422  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
1423  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1424  .P  .P
1425  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
1426  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
1427  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
1428  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1429  .P  .P
1430  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,
1431  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
1432  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1433  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1434  \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
1435  rounded down.  rounded down.
1436  .P  .P
1437  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1438  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1439  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
1440  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
1441  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
1442  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
1443  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1444  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1445  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
1446  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
1447  capturing subpatterns, the return value from a successful match is 1,  used for the first capturing subpattern, and so on. The value returned by
1448  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.
1449    For example, if two substrings have been captured, the returned value is 3. If
1450    there are no capturing subpatterns, the return value from a successful match is
1451    1, indicating that just the first pair of offsets has been set.
1452  .P  .P
1453  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
1454  string that it matched that is returned.  string that it matched that is returned.
1455  .P  .P
1456  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
1457  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
1458  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,
1459  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
1460  \fIovecsize\fP as zero. However, if the pattern contains back references and  \fIovecsize\fP as zero. However, if the pattern contains back references and
1461  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
1462  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 1675  These functions call \fBpcre_get_stringn Line 1742  These functions call \fBpcre_get_stringn
1742  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1743  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,
1744  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
1745  .  .P
1746    \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple
1747    subpatterns with the same number, you cannot use names to distinguish them,
1748    because names are not included in the compiled code. The matching process uses
1749    only numbers.
1750  .  .
1751  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
1752  .rs  .rs
# Line 1924  Cambridge CB2 3QH, England. Line 1995  Cambridge CB2 3QH, England.
1995  .rs  .rs
1996  .sp  .sp
1997  .nf  .nf
1998  Last updated: 10 September 2007  Last updated: 17 March 2009
1999  Copyright (c) 1997-2007 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
2000  .fi  .fi

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