/[pcre]/code/trunk/doc/pcreapi.3
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revision 412 by ph10, Sat Apr 11 10:34:37 2009 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 1008  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 1241  documentation for a discussion of saving Line 1246  documentation for a discussion of saving
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_START_OPTIMIZE,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_START_OPTIMIZE,
1249  PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and PCRE_PARTIAL_HARD.
1250  .sp  .sp
1251    PCRE_ANCHORED    PCRE_ANCHORED
1252  .sp  .sp
# Line 1326  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  .sp
1340    PCRE_NO_START_OPTIMIZE    PCRE_NO_START_OPTIMIZE
1341  .sp  .sp
# Line 1367  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 1568  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 1863  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 1886  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 1996  Cambridge CB2 3QH, England. Line 2011  Cambridge CB2 3QH, England.
2011  .rs  .rs
2012  .sp  .sp
2013  .nf  .nf
2014  Last updated: 11 April 2009  Last updated: 01 September 2009
2015  Copyright (c) 1997-2009 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
2016  .fi  .fi

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