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revision 336 by ph10, Sat Apr 12 15:59:03 2008 UTC revision 429 by ph10, Tue Sep 1 16:10:16 2009 UTC
# Line 135  Applications can use these to include su Line 135  Applications can use these to include su
135  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,
136  and \fBpcre_exec()\fP are used for compiling and matching regular expressions  and \fBpcre_exec()\fP are used for compiling and matching regular expressions
137  in a Perl-compatible manner. A sample program that demonstrates the simplest  in a Perl-compatible manner. A sample program that demonstrates the simplest
138  way of using them is provided in the file called \fIpcredemo.c\fP in the source  way of using them is provided in the file called \fIpcredemo.c\fP in the PCRE
139  distribution. The  source distribution. A listing of this program is given in the
140    .\" HREF
141    \fBpcredemo\fP
142    .\"
143    documentation, and the
144  .\" HREF  .\" HREF
145  \fBpcresample\fP  \fBpcresample\fP
146  .\"  .\"
# Line 317  properties is available; otherwise it is Line 321  properties is available; otherwise it is
321  .sp  .sp
322  The output is an integer whose value specifies the default character sequence  The output is an integer whose value specifies the default character sequence
323  that is recognized as meaning "newline". The four values that are supported  that is recognized as meaning "newline". The four values that are supported
324  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.
325  default should normally be the standard sequence for your operating system.  Though they are derived from ASCII, the same values are returned in EBCDIC
326    environments. The default should normally correspond to the standard sequence
327    for your operating system.
328  .sp  .sp
329    PCRE_CONFIG_BSR    PCRE_CONFIG_BSR
330  .sp  .sp
# Line 347  documentation. Line 353  documentation.
353  .sp  .sp
354    PCRE_CONFIG_MATCH_LIMIT    PCRE_CONFIG_MATCH_LIMIT
355  .sp  .sp
356  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
357  internal matching function calls in a \fBpcre_exec()\fP execution. Further  internal matching function calls in a \fBpcre_exec()\fP execution. Further
358  details are given with \fBpcre_exec()\fP below.  details are given with \fBpcre_exec()\fP below.
359  .sp  .sp
360    PCRE_CONFIG_MATCH_LIMIT_RECURSION    PCRE_CONFIG_MATCH_LIMIT_RECURSION
361  .sp  .sp
362  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
363  recursion when calling the internal matching function in a \fBpcre_exec()\fP  recursion when calling the internal matching function in a \fBpcre_exec()\fP
364  execution. Further details are given with \fBpcre_exec()\fP below.  execution. Further details are given with \fBpcre_exec()\fP below.
365  .sp  .sp
# Line 404  argument, which is an address (see below Line 410  argument, which is an address (see below
410  .P  .P
411  The \fIoptions\fP argument contains various bit settings that affect the  The \fIoptions\fP argument contains various bit settings that affect the
412  compilation. It should be zero if no options are required. The available  compilation. It should be zero if no options are required. The available
413  options are described below. Some of them, in particular, those that are  options are described below. Some of them (in particular, those that are
414  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
415  the detailed description in the  within the pattern (see the detailed description in the
416  .\" HREF  .\" HREF
417  \fBpcrepattern\fP  \fBpcrepattern\fP
418  .\"  .\"
419  documentation). For these options, the contents of the \fIoptions\fP argument  documentation). For those options that can be different in different parts of
420  specifies their initial settings at the start of compilation and execution. The  the pattern, the contents of the \fIoptions\fP argument specifies their initial
421  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
422  matching as well as at compile time.  PCRE_NEWLINE_\fIxxx\fP options can be set at the time of matching as well as at
423    compile time.
424  .P  .P
425  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
426  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
# Line 551  over the newline. Line 558  over the newline.
558  .sp  .sp
559    PCRE_JAVASCRIPT_COMPAT    PCRE_JAVASCRIPT_COMPAT
560  .sp  .sp
561  If this option is set, PCRE's behaviour is changed in some ways so that it is  If this option is set, PCRE's behaviour is changed in some ways so that it is
562  compatible with JavaScript rather than Perl. The changes are as follows:  compatible with JavaScript rather than Perl. The changes are as follows:
563  .P  .P
564  (1) A lone closing square bracket in a pattern causes a compile-time error,  (1) A lone closing square bracket in a pattern causes a compile-time error,
# Line 559  because this is illegal in JavaScript (b Line 566  because this is illegal in JavaScript (b
566  character). Thus, the pattern AB]CD becomes illegal when this option is set.  character). Thus, the pattern AB]CD becomes illegal when this option is set.
567  .P  .P
568  (2) At run time, a back reference to an unset subpattern group matches an empty  (2) At run time, a back reference to an unset subpattern group matches an empty
569  string (by default this causes the current matching path to fail). A pattern  string (by default this causes the current matching alternative to fail). A
570  such as (\1)(a) succeeds when this option is set (assuming it can find an "a"  pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
571  in the subject), whereas it fails by default, for Perl compatibility.  an "a" in the subject), whereas it fails by default, for Perl compatibility.
572  .sp  .sp
573    PCRE_MULTILINE    PCRE_MULTILINE
574  .sp  .sp
# Line 731  out of use. To avoid confusion, they hav Line 738  out of use. To avoid confusion, they hav
738    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
739    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
740    56  inconsistent NEWLINE options    56  inconsistent NEWLINE options
741    57  \eg is not followed by a braced, angle-bracketed, or quoted    57  \eg is not followed by a braced, angle-bracketed, or quoted
742          name/number or by a plain number          name/number or by a plain number
743    58  a numbered reference must not be zero    58  a numbered reference must not be zero
744    59  (*VERB) with an argument is not supported    59  (*VERB) with an argument is not supported
745    60  (*VERB) not recognized    60  (*VERB) not recognized
# Line 1005  different for each compiled pattern. Line 1012  different for each compiled pattern.
1012    PCRE_INFO_OKPARTIAL    PCRE_INFO_OKPARTIAL
1013  .sp  .sp
1014  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
1015  fourth argument should point to an \fBint\fP variable. The  fourth argument should point to an \fBint\fP variable. From release 8.00, this
1016    always returns 1, because the restrictions that previously applied to partial
1017    matching have been lifted. The
1018  .\" HREF  .\" HREF
1019  \fBpcrepartial\fP  \fBpcrepartial\fP
1020  .\"  .\"
1021  documentation lists the restrictions that apply to patterns when partial  documentation gives details of partial matching.
 matching is used.  
1022  .sp  .sp
1023    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1024  .sp  .sp
# Line 1237  documentation for a discussion of saving Line 1245  documentation for a discussion of saving
1245  .sp  .sp
1246  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
1247  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,
1248  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_START_OPTIMIZE,
1249    PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and PCRE_PARTIAL_HARD.
1250  .sp  .sp
1251    PCRE_ANCHORED    PCRE_ANCHORED
1252  .sp  .sp
# Line 1322  when using the /g modifier. It is possib Line 1331  when using the /g modifier. It is possib
1331  matching a null string by first trying the match again at the same offset with  matching a null string by first trying the match again at the same offset with
1332  PCRE_NOTEMPTY and PCRE_ANCHORED, and then if that fails by advancing the  PCRE_NOTEMPTY and PCRE_ANCHORED, and then if that fails by advancing the
1333  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
1334  code that demonstrates how to do this in the \fIpcredemo.c\fP sample program.  code that demonstrates how to do this in the
1335    .\" HREF
1336    \fBpcredemo\fP
1337    .\"
1338    sample program.
1339    .sp
1340      PCRE_NO_START_OPTIMIZE
1341    .sp
1342    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1343    a match, in order to speed up the process. For example, if it is known that a
1344    match must start with a specific character, it searches the subject for that
1345    character, and fails immediately if it cannot find it, without actually running
1346    the main matching function. When callouts are in use, these optimizations can
1347    cause them to be skipped. This option disables the "start-up" optimizations,
1348    causing performance to suffer, but ensuring that the callouts do occur.
1349  .sp  .sp
1350    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1351  .sp  .sp
# Line 1353  PCRE_NO_UTF8_CHECK is set, the effect of Line 1376  PCRE_NO_UTF8_CHECK is set, the effect of
1376  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
1377  UTF-8 character, is undefined. Your program may crash.  UTF-8 character, is undefined. Your program may crash.
1378  .sp  .sp
1379    PCRE_PARTIAL    PCRE_PARTIAL_HARD
1380      PCRE_PARTIAL_SOFT
1381  .sp  .sp
1382  This option turns on the partial matching feature. If the subject string fails  These options turn on the partial matching feature. For backwards
1383  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
1384  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
1385  the failure to match occurred only because there were not enough subject  not enough subject characters to complete the match. If this happens when
1386  characters), \fBpcre_exec()\fP returns PCRE_ERROR_PARTIAL instead of  PCRE_PARTIAL_HARD is set, \fBpcre_exec()\fP immediately returns
1387  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
1388  may appear in the pattern. These are discussed in the  by testing any other alternatives. Only if they all fail is PCRE_ERROR_PARTIAL
1389    returned (instead of PCRE_ERROR_NOMATCH). The portion of the string that
1390    provided the partial match is set as the first matching string. There is a more
1391    detailed discussion in the
1392  .\" HREF  .\" HREF
1393  \fBpcrepartial\fP  \fBpcrepartial\fP
1394  .\"  .\"
# Line 1371  documentation. Line 1398  documentation.
1398  .rs  .rs
1399  .sp  .sp
1400  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
1401  \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
1402  \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
1403  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
1404  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
1405  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.
1406  .P  .P
1407  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
1408  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 1409  pattern. Following the usage in Jeffrey Line 1436  pattern. Following the usage in Jeffrey
1436  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
1437  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1438  .P  .P
1439  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
1440  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
1441  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
1442  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1443  .P  .P
1444  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,
1445  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
1446  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1447  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1448  \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
1449  rounded down.  rounded down.
1450  .P  .P
1451  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1452  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1453  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
1454  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
1455  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
1456  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
1457  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1458  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1459  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
1460  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
1461  capturing subpatterns, the return value from a successful match is 1,  used for the first capturing subpattern, and so on. The value returned by
1462  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.
1463    For example, if two substrings have been captured, the returned value is 3. If
1464    there are no capturing subpatterns, the return value from a successful match is
1465    1, indicating that just the first pair of offsets has been set.
1466  .P  .P
1467  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
1468  string that it matched that is returned.  string that it matched that is returned.
1469  .P  .P
1470  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
1471  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
1472  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,
1473  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
1474  \fIovecsize\fP as zero. However, if the pattern contains back references and  \fIovecsize\fP as zero. However, if the pattern contains back references and
1475  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
1476  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 1551  documentation for details of partial mat Line 1581  documentation for details of partial mat
1581  .sp  .sp
1582    PCRE_ERROR_BADPARTIAL     (-13)    PCRE_ERROR_BADPARTIAL     (-13)
1583  .sp  .sp
1584  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
1585  are not supported for partial matching. See the  option was used with a compiled pattern containing items that were not
1586  .\" HREF  supported for partial matching. From release 8.00 onwards, there are no
1587  \fBpcrepartial\fP  restrictions on partial matching.
 .\"  
 documentation for details of partial matching.  
1588  .sp  .sp
1589    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
1590  .sp  .sp
# Line 1726  These functions call \fBpcre_get_stringn Line 1754  These functions call \fBpcre_get_stringn
1754  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1755  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,
1756  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
1757  .  .P
1758    \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple
1759    subpatterns with the same number, you cannot use names to distinguish them,
1760    because names are not included in the compiled code. The matching process uses
1761    only numbers.
1762  .  .
1763  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
1764  .rs  .rs
# Line 1842  Here is an example of a simple call to \ Line 1874  Here is an example of a simple call to \
1874  .sp  .sp
1875  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
1876  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,
1877  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,
1878  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
1879  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
1880  .sp  description is not repeated here.
1881    PCRE_PARTIAL  .sp
1882  .sp    PCRE_PARTIAL_HARD
1883  This has the same general effect as it does for \fBpcre_exec()\fP, but the    PCRE_PARTIAL_SOFT
1884  details are slightly different. When PCRE_PARTIAL is set for  .sp
1885  \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
1886  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
1887  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
1888  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
1889  matching string.  additional characters. This happens even if some complete matches have also
1890    been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
1891    is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached,
1892    there have been no complete matches, but there is still at least one matching
1893    possibility. The portion of the string that provided the longest partial match
1894    is set as the first matching string in both cases.
1895  .sp  .sp
1896    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
1897  .sp  .sp
# Line 1865  matching point in the subject string. Line 1902  matching point in the subject string.
1902  .sp  .sp
1903    PCRE_DFA_RESTART    PCRE_DFA_RESTART
1904  .sp  .sp
1905  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
1906  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
1907  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
1908  option requests this action; when it is set, the \fIworkspace\fP and  \fIworkspace\fP and \fIwscount\fP options must reference the same vector as
1909  \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
1910  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  
1911  .\" HREF  .\" HREF
1912  \fBpcrepartial\fP  \fBpcrepartial\fP
1913  .\"  .\"
# Line 1975  Cambridge CB2 3QH, England. Line 2011  Cambridge CB2 3QH, England.
2011  .rs  .rs
2012  .sp  .sp
2013  .nf  .nf
2014  Last updated: 12 April 2008  Last updated: 01 September 2009
2015  Copyright (c) 1997-2008 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
2016  .fi  .fi

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