/[pcre]/code/trunk/doc/pcreapi.3
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revision 441 by ph10, Wed Sep 9 10:14:40 2009 UTC revision 442 by ph10, Fri Sep 11 10:21:02 2009 UTC
# Line 1246  documentation for a discussion of saving Line 1246  documentation for a discussion of saving
1246  .sp  .sp
1247  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
1248  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,
1249  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_START_OPTIMIZE,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1250  PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and PCRE_PARTIAL_HARD.  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
1251    PCRE_PARTIAL_HARD.
1252  .sp  .sp
1253    PCRE_ANCHORED    PCRE_ANCHORED
1254  .sp  .sp
# Line 1322  match the empty string, the entire match Line 1323  match the empty string, the entire match
1323  .sp  .sp
1324    a?b?    a?b?
1325  .sp  .sp
1326  is applied to a string not beginning with "a" or "b", it matches the empty  is applied to a string not beginning with "a" or "b", it matches an empty
1327  string at the start of the subject. With PCRE_NOTEMPTY set, this match is not  string at the start of the subject. With PCRE_NOTEMPTY set, this match is not
1328  valid, so PCRE searches further into the string for occurrences of "a" or "b".  valid, so PCRE searches further into the string for occurrences of "a" or "b".
1329  .P  .sp
1330  Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case    PCRE_NOTEMPTY_ATSTART
1331  of a pattern match of the empty string within its \fBsplit()\fP function, and  .sp
1332  when using the /g modifier. It is possible to emulate Perl's behaviour after  This is like PCRE_NOTEMPTY, except that an empty string match that is not at
1333  matching a null string by first trying the match again at the same offset with  the start of the subject is permitted. If the pattern is anchored, such a match
1334  PCRE_NOTEMPTY and PCRE_ANCHORED, and then if that fails by advancing the  can occur only if the pattern contains \eK.
1335  starting offset (see below) and trying an ordinary match again. There is some  .P
1336  code that demonstrates how to do this in the  Perl has no direct equivalent of PCRE_NOTEMPTY or PCRE_NOTEMPTY_ATSTART, but it
1337    does make a special case of a pattern match of the empty string within its
1338    \fBsplit()\fP function, and when using the /g modifier. It is possible to
1339    emulate Perl's behaviour after matching a null string by first trying the match
1340    again at the same offset with PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED, and then
1341    if that fails, by advancing the starting offset (see below) and trying an
1342    ordinary match again. There is some code that demonstrates how to do this in
1343    the
1344  .\" HREF  .\" HREF
1345  \fBpcredemo\fP  \fBpcredemo\fP
1346  .\"  .\"
# Line 1875  Here is an example of a simple call to \ Line 1883  Here is an example of a simple call to \
1883  .sp  .sp
1884  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
1885  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,
1886  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1887  PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last  PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST,
1888  four of these are exactly the same as for \fBpcre_exec()\fP, so their  and PCRE_DFA_RESTART. All but the last four of these are exactly the same as
1889  description is not repeated here.  for \fBpcre_exec()\fP, so their description is not repeated here.
1890  .sp  .sp
1891    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
1892    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
# Line 2012  Cambridge CB2 3QH, England. Line 2020  Cambridge CB2 3QH, England.
2020  .rs  .rs
2021  .sp  .sp
2022  .nf  .nf
2023  Last updated: 09 September 2009  Last updated: 11 September 2009
2024  Copyright (c) 1997-2009 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
2025  .fi  .fi

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