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revision 389 by ph10, Sun Mar 15 18:24:05 2009 UTC revision 440 by ph10, Wed Sep 9 10:14:40 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 145  documentation describes how to compile a Line 149  documentation describes how to compile a
149  A second matching function, \fBpcre_dfa_exec()\fP, which is not  A second matching function, \fBpcre_dfa_exec()\fP, which is not
150  Perl-compatible, is also provided. This uses a different algorithm for the  Perl-compatible, is also provided. This uses a different algorithm for the
151  matching. The alternative algorithm finds all possible matches (at a given  matching. The alternative algorithm finds all possible matches (at a given
152  point in the subject), and scans the subject just once. However, this algorithm  point in the subject), and scans the subject just once (unless there are
153  does not return captured substrings. A description of the two matching  lookbehind assertions). However, this algorithm does not return captured
154  algorithms and their advantages and disadvantages is given in the  substrings. A description of the two matching algorithms and their advantages
155    and disadvantages is given in the
156  .\" HREF  .\" HREF
157  \fBpcrematching\fP  \fBpcrematching\fP
158  .\"  .\"
# Line 317  properties is available; otherwise it is Line 322  properties is available; otherwise it is
322  .sp  .sp
323  The output is an integer whose value specifies the default character sequence  The output is an integer whose value specifies the default character sequence
324  that is recognized as meaning "newline". The four values that are supported  that is recognized as meaning "newline". The four values that are supported
325  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.
326  default should normally be the standard sequence for your operating system.  Though they are derived from ASCII, the same values are returned in EBCDIC
327    environments. The default should normally correspond to the standard sequence
328    for your operating system.
329  .sp  .sp
330    PCRE_CONFIG_BSR    PCRE_CONFIG_BSR
331  .sp  .sp
# Line 404  argument, which is an address (see below Line 411  argument, which is an address (see below
411  .P  .P
412  The \fIoptions\fP argument contains various bit settings that affect the  The \fIoptions\fP argument contains various bit settings that affect the
413  compilation. It should be zero if no options are required. The available  compilation. It should be zero if no options are required. The available
414  options are described below. Some of them, in particular, those that are  options are described below. Some of them (in particular, those that are
415  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
416  the detailed description in the  within the pattern (see the detailed description in the
417  .\" HREF  .\" HREF
418  \fBpcrepattern\fP  \fBpcrepattern\fP
419  .\"  .\"
420  documentation). For these options, the contents of the \fIoptions\fP argument  documentation). For those options that can be different in different parts of
421  specifies their initial settings at the start of compilation and execution. The  the pattern, the contents of the \fIoptions\fP argument specifies their initial
422  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
423  matching as well as at compile time.  PCRE_NEWLINE_\fIxxx\fP options can be set at the time of matching as well as at
424    compile time.
425  .P  .P
426  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
427  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
# Line 1004  different for each compiled pattern. Line 1012  different for each compiled pattern.
1012  .sp  .sp
1013    PCRE_INFO_OKPARTIAL    PCRE_INFO_OKPARTIAL
1014  .sp  .sp
1015  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 with
1016  fourth argument should point to an \fBint\fP variable. The  \fBpcre_exec()\fP, otherwise 0. The fourth argument should point to an
1017    \fBint\fP variable. From release 8.00, this always returns 1, because the
1018    restrictions that previously applied to partial matching have been lifted. The
1019  .\" HREF  .\" HREF
1020  \fBpcrepartial\fP  \fBpcrepartial\fP
1021  .\"  .\"
1022  documentation lists the restrictions that apply to patterns when partial  documentation gives details of partial matching.
 matching is used.  
1023  .sp  .sp
1024    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1025  .sp  .sp
# Line 1210  with a \fBpcre_extra\fP block in which \ Line 1219  with a \fBpcre_extra\fP block in which \
1219  PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the \fIflags\fP field. If the limit  PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the \fIflags\fP field. If the limit
1220  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.
1221  .P  .P
1222  The \fIpcre_callout\fP field is used in conjunction with the "callout" feature,  The \fIcallout_data\fP field is used in conjunction with the "callout" feature,
1223  which is described in the  and is described in the
1224  .\" HREF  .\" HREF
1225  \fBpcrecallout\fP  \fBpcrecallout\fP
1226  .\"  .\"
# Line 1238  documentation for a discussion of saving Line 1247  documentation for a discussion of saving
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_NO_START_OPTIMIZE,
1250  PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and PCRE_PARTIAL_HARD.
1251  .sp  .sp
1252    PCRE_ANCHORED    PCRE_ANCHORED
1253  .sp  .sp
# Line 1323  when using the /g modifier. It is possib Line 1332  when using the /g modifier. It is possib
1332  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
1333  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
1334  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
1335  code that demonstrates how to do this in the \fIpcredemo.c\fP sample program.  code that demonstrates how to do this in the
1336    .\" HREF
1337    \fBpcredemo\fP
1338    .\"
1339    sample program.
1340  .sp  .sp
1341    PCRE_NO_START_OPTIMIZE    PCRE_NO_START_OPTIMIZE
1342  .sp  .sp
1343  There are a number of optimizations that \fBpcre_exec()\fP uses at the start of  There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1344  a match, in order to speed up the process. For example, if it is known that a  a match, in order to speed up the process. For example, if it is known that a
1345  match must start with a specific character, it searches the subject for that  match must start with a specific character, it searches the subject for that
1346  character, and fails immediately if it cannot find it, without actually running  character, and fails immediately if it cannot find it, without actually running
# Line 1364  PCRE_NO_UTF8_CHECK is set, the effect of Line 1377  PCRE_NO_UTF8_CHECK is set, the effect of
1377  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
1378  UTF-8 character, is undefined. Your program may crash.  UTF-8 character, is undefined. Your program may crash.
1379  .sp  .sp
1380    PCRE_PARTIAL    PCRE_PARTIAL_HARD
1381      PCRE_PARTIAL_SOFT
1382  .sp  .sp
1383  This option turns on the partial matching feature. If the subject string fails  These options turn on the partial matching feature. For backwards
1384  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
1385  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
1386  the failure to match occurred only because there were not enough subject  not enough subject characters to complete the match. If this happens when
1387  characters), \fBpcre_exec()\fP returns PCRE_ERROR_PARTIAL instead of  PCRE_PARTIAL_HARD is set, \fBpcre_exec()\fP immediately returns
1388  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
1389  may appear in the pattern. These are discussed in the  by testing any other alternatives. Only if they all fail is PCRE_ERROR_PARTIAL
1390    returned (instead of PCRE_ERROR_NOMATCH). The portion of the string that
1391    was inspected when the partial match was found is set as the first matching
1392    string. There is a more detailed discussion in the
1393  .\" HREF  .\" HREF
1394  \fBpcrepartial\fP  \fBpcrepartial\fP
1395  .\"  .\"
# Line 1565  documentation for details of partial mat Line 1582  documentation for details of partial mat
1582  .sp  .sp
1583    PCRE_ERROR_BADPARTIAL     (-13)    PCRE_ERROR_BADPARTIAL     (-13)
1584  .sp  .sp
1585  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
1586  are not supported for partial matching. See the  option was used with a compiled pattern containing items that were not
1587  .\" HREF  supported for partial matching. From release 8.00 onwards, there are no
1588  \fBpcrepartial\fP  restrictions on partial matching.
 .\"  
 documentation for details of partial matching.  
1589  .sp  .sp
1590    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
1591  .sp  .sp
# Line 1742  appropriate. \fBNOTE:\fP If PCRE_DUPNAME Line 1757  appropriate. \fBNOTE:\fP If PCRE_DUPNAME
1757  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
1758  .P  .P
1759  \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple  \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple
1760  subpatterns with the same number, you cannot use names to distinguish them,  subpatterns with the same number, you cannot use names to distinguish them,
1761  because names are not included in the compiled code. The matching process uses  because names are not included in the compiled code. The matching process uses
1762  only numbers.  only numbers.
1763  .  .
1764  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
# Line 1820  a compiled pattern, using a matching alg Line 1835  a compiled pattern, using a matching alg
1835  just once, and does not backtrack. This has different characteristics to the  just once, and does not backtrack. This has different characteristics to the
1836  normal algorithm, and is not compatible with Perl. Some of the features of PCRE  normal algorithm, and is not compatible with Perl. Some of the features of PCRE
1837  patterns are not supported. Nevertheless, there are times when this kind of  patterns are not supported. Nevertheless, there are times when this kind of
1838  matching can be useful. For a discussion of the two matching algorithms, see  matching can be useful. For a discussion of the two matching algorithms, and a
1839  the  list of features that \fBpcre_dfa_exec()\fP does not support, see the
1840  .\" HREF  .\" HREF
1841  \fBpcrematching\fP  \fBpcrematching\fP
1842  .\"  .\"
# Line 1860  Here is an example of a simple call to \ Line 1875  Here is an example of a simple call to \
1875  .sp  .sp
1876  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
1877  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,
1878  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,
1879  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
1880  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
1881  .sp  description is not repeated here.
1882    PCRE_PARTIAL  .sp
1883  .sp    PCRE_PARTIAL_HARD
1884  This has the same general effect as it does for \fBpcre_exec()\fP, but the    PCRE_PARTIAL_SOFT
1885  details are slightly different. When PCRE_PARTIAL is set for  .sp
1886  \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
1887  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
1888  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
1889  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
1890  matching string.  additional characters. This happens even if some complete matches have also
1891    been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
1892    is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached,
1893    there have been no complete matches, but there is still at least one matching
1894    possibility. The portion of the string that was inspected when the longest
1895    partial match was found is set as the first matching string in both cases.
1896  .sp  .sp
1897    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
1898  .sp  .sp
# Line 1883  matching point in the subject string. Line 1903  matching point in the subject string.
1903  .sp  .sp
1904    PCRE_DFA_RESTART    PCRE_DFA_RESTART
1905  .sp  .sp
1906  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
1907  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
1908  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
1909  option requests this action; when it is set, the \fIworkspace\fP and  \fIworkspace\fP and \fIwscount\fP options must reference the same vector as
1910  \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
1911  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  
1912  .\" HREF  .\" HREF
1913  \fBpcrepartial\fP  \fBpcrepartial\fP
1914  .\"  .\"
# Line 1993  Cambridge CB2 3QH, England. Line 2012  Cambridge CB2 3QH, England.
2012  .rs  .rs
2013  .sp  .sp
2014  .nf  .nf
2015  Last updated: 15 March 2009  Last updated: 09 September 2009
2016  Copyright (c) 1997-2009 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
2017  .fi  .fi

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