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revision 568 by ph10, Sat Nov 6 17:36:26 2010 UTC revision 576 by ph10, Sun Nov 21 18:45:10 2010 UTC
# Line 428  within the pattern (see the detailed des Line 428  within the pattern (see the detailed des
428  documentation). For those options that can be different in different parts of  documentation). For those options that can be different in different parts of
429  the pattern, the contents of the \fIoptions\fP argument specifies their  the pattern, the contents of the \fIoptions\fP argument specifies their
430  settings at the start of compilation and execution. The PCRE_ANCHORED,  settings at the start of compilation and execution. The PCRE_ANCHORED,
431  PCRE_BSR_\fIxxx\fP, and PCRE_NEWLINE_\fIxxx\fP options can be set at the time  PCRE_BSR_\fIxxx\fP, PCRE_NEWLINE_\fIxxx\fP, PCRE_NO_UTF8_CHECK, and
432  of matching as well as at compile time.  PCRE_NO_START_OPT options can be set at the time of matching as well as at
433    compile time.
434  .P  .P
435  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
436  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
437  NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual  NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual
438  error message. This is a static string that is part of the library. You must  error message. This is a static string that is part of the library. You must
439  not try to free it. The byte offset from the start of the pattern to the  not try to free it. The offset from the start of the pattern to the byte that
440  character that was being processed when the error was discovered is placed in  was being processed when the error was discovered is placed in the variable
441  the variable pointed to by \fIerroffset\fP, which must not be NULL. If it is,  pointed to by \fIerroffset\fP, which must not be NULL. If it is, an immediate
442  an immediate error is given. Some errors are not detected until checks are  error is given. Some errors are not detected until checks are carried out when
443  carried out when the whole pattern has been scanned; in this case the offset is  the whole pattern has been scanned; in this case the offset is set to the end
444  set to the end of the pattern.  of the pattern.
445    .P
446    Note that the offset is in bytes, not characters, even in UTF-8 mode. It may
447    point into the middle of a UTF-8 character (for example, when
448    PCRE_ERROR_BADUTF8 is returned for an invalid UTF-8 string).
449  .P  .P
450  If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the  If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the
451  \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is  \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is
# Line 519  pattern. Line 524  pattern.
524  .sp  .sp
525    PCRE_DOTALL    PCRE_DOTALL
526  .sp  .sp
527  If this bit is set, a dot metacharater in the pattern matches all characters,  If this bit is set, a dot metacharacter in the pattern matches a character of
528  including those that indicate newline. Without it, a dot does not match when  any value, including one that indicates a newline. However, it only ever
529  the current position is at a newline. This option is equivalent to Perl's /s  matches one character, even if newlines are coded as CRLF. Without this option,
530  option, and it can be changed within a pattern by a (?s) option setting. A  a dot does not match when the current position is at a newline. This option is
531  negative class such as [^a] always matches newline characters, independent of  equivalent to Perl's /s option, and it can be changed within a pattern by a
532  the setting of this option.  (?s) option setting. A negative class such as [^a] always matches newline
533    characters, independent of the setting of this option.
534  .sp  .sp
535    PCRE_DUPNAMES    PCRE_DUPNAMES
536  .sp  .sp
# Line 546  unescaped # outside a character class an Line 552  unescaped # outside a character class an
552  ignored. This is equivalent to Perl's /x option, and it can be changed within a  ignored. This is equivalent to Perl's /x option, and it can be changed within a
553  pattern by a (?x) option setting.  pattern by a (?x) option setting.
554  .P  .P
555    Which characters are interpreted as newlines
556    is controlled by the options passed to \fBpcre_compile()\fP or by a special
557    sequence at the start of the pattern, as described in the section entitled
558    .\" HTML <a href="pcrepattern.html#newlines">
559    .\" </a>
560    "Newline conventions"
561    .\"
562    in the \fBpcrepattern\fP documentation. Note that the end of this type of
563    comment is a literal newline sequence in the pattern; escape sequences that
564    happen to represent a newline do not count.
565    .P
566  This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
567  Note, however, that this applies only to data characters. Whitespace characters  Note, however, that this applies only to data characters. Whitespace characters
568  may never appear within special character sequences in a pattern, for example  may never appear within special character sequences in a pattern, for example
569  within the sequence (?( which introduces a conditional subpattern.  within the sequence (?( that introduces a conditional subpattern.
570  .sp  .sp
571    PCRE_EXTRA    PCRE_EXTRA
572  .sp  .sp
# Line 624  option, the combination may or may not b Line 641  option, the combination may or may not b
641  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but
642  other combinations may yield unused numbers and cause an error.  other combinations may yield unused numbers and cause an error.
643  .P  .P
644  The only time that a line break is specially recognized when compiling a  The only time that a line break in a pattern is specially recognized when
645  pattern is if PCRE_EXTENDED is set, and an unescaped # outside a character  compiling is when PCRE_EXTENDED is set. CR and LF are whitespace characters,
646  class is encountered. This indicates a comment that lasts until after the next  and so are ignored in this mode. Also, an unescaped # outside a character class
647  line break sequence. In other circumstances, line break sequences are treated  indicates a comment that lasts until after the next line break sequence. In
648  as literal data, except that in PCRE_EXTENDED mode, both CR and LF are treated  other circumstances, line break sequences in patterns are treated as literal
649  as whitespace characters and are therefore ignored.  data.
650  .P  .P
651  The newline option that is set at compile time becomes the default that is used  The newline option that is set at compile time becomes the default that is used
652  for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.  for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.
# Line 642  were followed by ?: but named parenthese Line 659  were followed by ?: but named parenthese
659  they acquire numbers in the usual way). There is no equivalent of this option  they acquire numbers in the usual way). There is no equivalent of this option
660  in Perl.  in Perl.
661  .sp  .sp
662      NO_START_OPTIMIZE
663    .sp
664    This is an option that acts at matching time; that is, it is really an option
665    for \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. If it is set at compile time,
666    it is remembered with the compiled pattern and assumed at matching time. For
667    details see the discussion of PCRE_NO_START_OPTIMIZE
668    .\" HTML <a href="#execoptions">
669    .\" </a>
670    below.
671    .\"
672    .sp
673    PCRE_UCP    PCRE_UCP
674  .sp  .sp
675  This option changes the way PCRE processes \eb, \ed, \es, \ew, and some of the  This option changes the way PCRE processes \eB, \eb, \eD, \ed, \eS, \es, \eW,
676  POSIX character classes. By default, only ASCII characters are recognized, but  \ew, and some of the POSIX character classes. By default, only ASCII characters
677  if PCRE_UCP is set, Unicode properties are used instead to classify characters.  are recognized, but if PCRE_UCP is set, Unicode properties are used instead to
678  More details are given in the section on  classify characters. More details are given in the section on
679  .\" HTML <a href="pcre.html#genericchartypes">  .\" HTML <a href="pcre.html#genericchartypes">
680  .\" </a>  .\" </a>
681  generic character types  generic character types
# Line 852  matching. Line 880  matching.
880  The two optimizations just described can be disabled by setting the  The two optimizations just described can be disabled by setting the
881  PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or  PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or
882  \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains  \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains
883  callouts, or make use of (*MARK), and you make use of these in cases where  callouts or (*MARK), and you want to make use of these facilities in cases
884  matching fails. See the discussion of PCRE_NO_START_OPTIMIZE  where matching fails. See the discussion of PCRE_NO_START_OPTIMIZE
885  .\" HTML <a href="#execoptions">  .\" HTML <a href="#execoptions">
886  .\" </a>  .\" </a>
887  below.  below.
# Line 1450  the Line 1478  the
1478  .\" HREF  .\" HREF
1479  \fBpcredemo\fP  \fBpcredemo\fP
1480  .\"  .\"
1481  sample program. In the most general case, you have to check to see if the  sample program. In the most general case, you have to check to see if the
1482  newline convention recognizes CRLF as a newline, and if so, and the current  newline convention recognizes CRLF as a newline, and if so, and the current
1483  character is CR followed by LF, advance the starting offset by two characters  character is CR followed by LF, advance the starting offset by two characters
1484  instead of one.  instead of one.
1485  .sp  .sp
# Line 1471  a pre-scan of the subject that takes pla Line 1499  a pre-scan of the subject that takes pla
1499  The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly  The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1500  causing performance to suffer, but ensuring that in cases where the result is  causing performance to suffer, but ensuring that in cases where the result is
1501  "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)  "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
1502  are considered at every possible starting position in the subject string.  are considered at every possible starting position in the subject string. If
1503    PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching
1504    time.
1505    .P
1506  Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.  Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
1507  Consider the pattern  Consider the pattern
1508  .sp  .sp
# Line 1515  in the main Line 1546  in the main
1546  \fBpcre\fP  \fBpcre\fP
1547  .\"  .\"
1548  page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns  page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1549  the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains a value that does  the error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is
1550  not point to the start of a UTF-8 character (or to the end of the subject),  a truncated UTF-8 character at the end of the subject, PCRE_ERROR_SHORTUTF8. If
1551  PCRE_ERROR_BADUTF8_OFFSET is returned.  \fIstartoffset\fP contains a value that does not point to the start of a UTF-8
1552    character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
1553    returned.
1554  .P  .P
1555  If you already know that your subject is valid, and you want to skip these  If you already know that your subject is valid, and you want to skip these
1556  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when
# Line 1545  but only if no complete match can be fou Line 1578  but only if no complete match can be fou
1578  If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a  If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a
1579  partial match is found, \fBpcre_exec()\fP immediately returns  partial match is found, \fBpcre_exec()\fP immediately returns
1580  PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,  PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,
1581  when PCRE_PARTIAL_HARD is set, a partial match is considered to be more  when PCRE_PARTIAL_HARD is set, a partial match is considered to be more
1582  important that an alternative complete match.  important that an alternative complete match.
1583  .P  .P
1584  In both cases, the portion of the string that was inspected when the partial  In both cases, the portion of the string that was inspected when the partial
# Line 1562  documentation. Line 1595  documentation.
1595  .sp  .sp
1596  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
1597  \fIsubject\fP, a length (in bytes) in \fIlength\fP, and a starting byte offset  \fIsubject\fP, a length (in bytes) in \fIlength\fP, and a starting byte offset
1598  in \fIstartoffset\fP. If this is negative or greater than the length of the  in \fIstartoffset\fP. If this is negative or greater than the length of the
1599  subject, \fBpcre_exec()\fP returns PCRE_ERROR_BADOFFSET.  subject, \fBpcre_exec()\fP returns PCRE_ERROR_BADOFFSET. When the starting
1600  .P  offset is zero, the search for a match starts at the beginning of the subject,
1601  In UTF-8 mode, the byte offset must point to the start of a UTF-8 character (or  and this is by far the most common case. In UTF-8 mode, the byte offset must
1602  the end of the subject). Unlike the pattern string, the subject may contain  point to the start of a UTF-8 character (or the end of the subject). Unlike the
1603  binary zero bytes. When the starting offset is zero, the search for a match  pattern string, the subject may contain binary zero bytes.
 starts at the beginning of the subject, and this is by far the most common  
 case.  
1604  .P  .P
1605  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
1606  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 1598  do this in the Line 1629  do this in the
1629  .\" HREF  .\" HREF
1630  \fBpcredemo\fP  \fBpcredemo\fP
1631  .\"  .\"
1632  sample program. In the most general case, you have to check to see if the  sample program. In the most general case, you have to check to see if the
1633  newline convention recognizes CRLF as a newline, and if so, and the current  newline convention recognizes CRLF as a newline, and if so, and the current
1634  character is CR followed by LF, advance the starting offset by two characters  character is CR followed by LF, advance the starting offset by two characters
1635  instead of one.  instead of one.
1636  .P  .P
# Line 1756  documentation for details. Line 1787  documentation for details.
1787    PCRE_ERROR_BADUTF8        (-10)    PCRE_ERROR_BADUTF8        (-10)
1788  .sp  .sp
1789  A string that contains an invalid UTF-8 byte sequence was passed as a subject.  A string that contains an invalid UTF-8 byte sequence was passed as a subject.
1790    However, if PCRE_PARTIAL_HARD is set and the problem is a truncated UTF-8
1791    character at the end of the subject, PCRE_ERROR_SHORTUTF8 is used instead.
1792  .sp  .sp
1793    PCRE_ERROR_BADUTF8_OFFSET (-11)    PCRE_ERROR_BADUTF8_OFFSET (-11)
1794  .sp  .sp
1795  The UTF-8 byte sequence that was passed as a subject was valid, but the value  The UTF-8 byte sequence that was passed as a subject was valid, but the value
1796  of \fIstartoffset\fP did not point to the beginning of a UTF-8 character.  of \fIstartoffset\fP did not point to the beginning of a UTF-8 character or the
1797    end of the subject.
1798  .sp  .sp
1799    PCRE_ERROR_PARTIAL        (-12)    PCRE_ERROR_PARTIAL        (-12)
1800  .sp  .sp
# Line 1798  An invalid combination of PCRE_NEWLINE_\ Line 1832  An invalid combination of PCRE_NEWLINE_\
1832  .sp  .sp
1833    PCRE_ERROR_BADOFFSET      (-24)    PCRE_ERROR_BADOFFSET      (-24)
1834  .sp  .sp
1835  The value of \fIstartoffset\fP was negative or greater than the length of the  The value of \fIstartoffset\fP was negative or greater than the length of the
1836  subject, that is, the value in \fIlength\fP.  subject, that is, the value in \fIlength\fP.
1837    .sp
1838      PCRE_ERROR_SHORTUTF8      (-25)
1839    .sp
1840    The subject string ended with an incomplete (truncated) UTF-8 character, and
1841    the PCRE_PARTIAL_HARD option was set. Without this option, PCRE_ERROR_BADUTF8
1842    is returned in this situation.
1843  .P  .P
1844  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
1845  .  .
# Line 2227  Cambridge CB2 3QH, England. Line 2267  Cambridge CB2 3QH, England.
2267  .rs  .rs
2268  .sp  .sp
2269  .nf  .nf
2270  Last updated: 06 November 2010  Last updated: 21 November 2010
2271  Copyright (c) 1997-2010 University of Cambridge.  Copyright (c) 1997-2010 University of Cambridge.
2272  .fi  .fi

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