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revision 191 by ph10, Mon Jul 30 11:13:54 2007 UTC revision 231 by ph10, Tue Sep 11 11:15:33 2007 UTC
# Line 218  points during a matching operation. Deta Line 218  points during a matching operation. Deta
218  documentation.  documentation.
219  .  .
220  .  .
221    .\" HTML <a name="newlines"></a>
222  .SH NEWLINES  .SH NEWLINES
223  .rs  .rs
224  .sp  .sp
# Line 235  The default default is LF, which is the Line 236  The default default is LF, which is the
236  default can be overridden, either when a pattern is compiled, or when it is  default can be overridden, either when a pattern is compiled, or when it is
237  matched.  matched.
238  .P  .P
239    At compile time, the newline convention can be specified by the \fIoptions\fP
240    argument of \fBpcre_compile()\fP, or it can be specified by special text at the
241    start of the pattern itself; this overrides any other settings. See the
242    .\" HREF
243    \fBpcrepattern\fP
244    .\"
245    page for details of the special character sequences.
246    .P
247  In the PCRE documentation the word "newline" is used to mean "the character or  In the PCRE documentation the word "newline" is used to mean "the character or
248  pair of characters that indicate a line break". The choice of newline  pair of characters that indicate a line break". The choice of newline
249  convention affects the handling of the dot, circumflex, and dollar  convention affects the handling of the dot, circumflex, and dollar
250  metacharacters, the handling of #-comments in /x mode, and, when CRLF is a  metacharacters, the handling of #-comments in /x mode, and, when CRLF is a
251  recognized line ending sequence, the match position advancement for a  recognized line ending sequence, the match position advancement for a
252  non-anchored pattern. The choice of newline convention does not affect the  non-anchored pattern. There is more detail about this in the
253  interpretation of the \en or \er escape sequences.  .\" HTML <a href="#execoptions">
254    .\" </a>
255    section on \fBpcre_exec()\fP options
256    .\"
257    below.
258    .P
259    The choice of newline convention does not affect the interpretation of
260    the \en or \er escape sequences, nor does it affect what \eR matches, which is
261    controlled in a similar way, but by separate options.
262  .  .
263  .  .
264  .SH MULTITHREADING  .SH MULTITHREADING
# Line 303  that is recognized as meaning "newline". Line 320  that is recognized as meaning "newline".
320  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. The
321  default should normally be the standard sequence for your operating system.  default should normally be the standard sequence for your operating system.
322  .sp  .sp
323      PCRE_CONFIG_BSR
324    .sp
325    The output is an integer whose value indicates what character sequences the \eR
326    escape sequence matches by default. A value of 0 means that \eR matches any
327    Unicode line ending sequence; a value of 1 means that \eR matches only CR, LF,
328    or CRLF. The default can be overridden when a pattern is compiled or matched.
329    .sp
330    PCRE_CONFIG_LINK_SIZE    PCRE_CONFIG_LINK_SIZE
331  .sp  .sp
332  The output is an integer that contains the number of bytes used for internal  The output is an integer that contains the number of bytes used for internal
# Line 444  facility, see the Line 468  facility, see the
468  .\"  .\"
469  documentation.  documentation.
470  .sp  .sp
471      PCRE_BSR_ANYCRLF
472      PCRE_BSR_UNICODE
473    .sp
474    These options (which are mutually exclusive) control what the \eR escape
475    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
476    match any Unicode newline sequence. The default is specified when PCRE is
477    built. It can be overridden from within the pattern, or by setting an option
478    when a compiled pattern is matched.
479    .sp
480    PCRE_CASELESS    PCRE_CASELESS
481  .sp  .sp
482  If this bit is set, letters in the pattern match both upper and lower case  If this bit is set, letters in the pattern match both upper and lower case
# Line 601  page. Line 634  page.
634    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
635  .sp  .sp
636  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
637  automatically checked. If an invalid UTF-8 sequence of bytes is found,  automatically checked. There is a discussion about the
638  \fBpcre_compile()\fP returns an error. If you already know that your pattern is  .\" HTML <a href="pcre.html#utf8strings">
639  valid, and you want to skip this check for performance reasons, you can set the  .\" </a>
640  PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid  validity of UTF-8 strings
641  UTF-8 string as a pattern is undefined. It may cause your program to crash.  .\"
642  Note that this option can also be passed to \fBpcre_exec()\fP and  in the main
643  \fBpcre_dfa_exec()\fP, to suppress the UTF-8 validity checking of subject  .\" HREF
644  strings.  \fBpcre\fP
645    .\"
646    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_compile()\fP
647    returns an error. If you already know that your pattern is valid, and you want
648    to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
649    option. When it is set, the effect of passing an invalid UTF-8 string as a
650    pattern is undefined. It may cause your program to crash. Note that this option
651    can also be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress
652    the UTF-8 validity checking of subject strings.
653  .  .
654  .  .
655  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 669  out of use. To avoid confusion, they hav Line 710  out of use. To avoid confusion, they hav
710    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
711    48  subpattern name is too long (maximum 32 characters)    48  subpattern name is too long (maximum 32 characters)
712    49  too many named subpatterns (maximum 10,000)    49  too many named subpatterns (maximum 10,000)
713    50  repeated subpattern is too long    50  [this code is not in use]
714    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 (not in UTF-8 mode)
715    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
716    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern not found
717    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
718    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
719    56  inconsistent NEWLINE options"    56  inconsistent NEWLINE options
720    57  \eg is not followed by a braced name or an optionally braced    57  \eg is not followed by a braced name or an optionally braced
721          non-zero number          non-zero number
722    58  (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number    58  (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number
# Line 874  table indicating a fixed set of bytes fo Line 915  table indicating a fixed set of bytes fo
915  string, a pointer to the table is returned. Otherwise NULL is returned. The  string, a pointer to the table is returned. Otherwise NULL is returned. The
916  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
917  .sp  .sp
918      PCRE_INFO_HASCRORLF
919    .sp
920    Return 1 if the pattern contains any explicit matches for CR or LF characters,
921    otherwise 0. The fourth argument should point to an \fBint\fP variable. An
922    explicit match is either a literal CR or LF character, or \er or \en.
923    .sp
924    PCRE_INFO_JCHANGED    PCRE_INFO_JCHANGED
925  .sp  .sp
926  Return 1 if the (?J) option setting is used in the pattern, otherwise 0. The  Return 1 if the (?J) option setting is used in the pattern, otherwise 0. The
# Line 947  matching is used. Line 994  matching is used.
994  Return a copy of the options with which the pattern was compiled. The fourth  Return a copy of the options with which the pattern was compiled. The fourth
995  argument should point to an \fBunsigned long int\fP variable. These option bits  argument should point to an \fBunsigned long int\fP variable. These option bits
996  are those specified in the call to \fBpcre_compile()\fP, modified by any  are those specified in the call to \fBpcre_compile()\fP, modified by any
997  top-level option settings within the pattern itself.  top-level option settings at the start of the pattern itself. In other words,
998    they are the options that will be in force when matching starts. For example,
999    if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the
1000    result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED.
1001  .P  .P
1002  A pattern is automatically anchored by PCRE if all of its top-level  A pattern is automatically anchored by PCRE if all of its top-level
1003  alternatives begin with one of the following:  alternatives begin with one of the following:
# Line 1158  called. See the Line 1208  called. See the
1208  .\"  .\"
1209  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1210  .  .
1211    .\" HTML <a name="execoptions"></a>
1212  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
1213  .rs  .rs
1214  .sp  .sp
# Line 1172  matching position. If a pattern was comp Line 1223  matching position. If a pattern was comp
1223  to be anchored by virtue of its contents, it cannot be made unachored at  to be anchored by virtue of its contents, it cannot be made unachored at
1224  matching time.  matching time.
1225  .sp  .sp
1226      PCRE_BSR_ANYCRLF
1227      PCRE_BSR_UNICODE
1228    .sp
1229    These options (which are mutually exclusive) control what the \eR escape
1230    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1231    match any Unicode newline sequence. These options override the choice that was
1232    made or defaulted when the pattern was compiled.
1233    .sp
1234    PCRE_NEWLINE_CR    PCRE_NEWLINE_CR
1235    PCRE_NEWLINE_LF    PCRE_NEWLINE_LF
1236    PCRE_NEWLINE_CRLF    PCRE_NEWLINE_CRLF
# Line 1183  the pattern was compiled. For details, s Line 1242  the pattern was compiled. For details, s
1242  \fBpcre_compile()\fP above. During matching, the newline choice affects the  \fBpcre_compile()\fP above. During matching, the newline choice affects the
1243  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1244  the way the match position is advanced after a match failure for an unanchored  the way the match position is advanced after a match failure for an unanchored
1245  pattern. When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is  pattern.
1246  set, and a match attempt fails when the current position is at a CRLF sequence,  .P
1247  the match position is advanced by two characters instead of one, in other  When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a
1248  words, to after the CRLF.  match attempt for an unanchored pattern fails when the current position is at a
1249    CRLF sequence, and the pattern contains no explicit matches for CR or LF
1250    characters, the match position is advanced by two characters instead of one, in
1251    other words, to after the CRLF.
1252    .P
1253    The above rule is a compromise that makes the most common cases work as
1254    expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1255    set), it does not match the string "\er\enA" because, after failing at the
1256    start, it skips both the CR and the LF before retrying. However, the pattern
1257    [\er\en]A does match that string, because it contains an explicit CR or LF
1258    reference, and so advances only by one character after the first failure.
1259    .P
1260    An explicit match for CR of LF is either a literal appearance of one of those
1261    characters, or one of the \er or \en escape sequences. Implicit matches such as
1262    [^X] do not count, nor does \es (which includes CR and LF in the characters
1263    that it matches).
1264    .P
1265    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1266    valid newline sequence and explicit \er or \en escapes appear in the pattern.
1267  .sp  .sp
1268    PCRE_NOTBOL    PCRE_NOTBOL
1269  .sp  .sp
# Line 1229  code that demonstrates how to do this in Line 1306  code that demonstrates how to do this in
1306  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8
1307  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1308  The value of \fIstartoffset\fP is also checked to ensure that it points to the  The value of \fIstartoffset\fP is also checked to ensure that it points to the
1309  start of a UTF-8 character. If an invalid UTF-8 sequence of bytes is found,  start of a UTF-8 character. There is a discussion about the validity of UTF-8
1310  \fBpcre_exec()\fP returns the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP  strings in the
1311  contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.  .\" HTML <a href="pcre.html#utf8strings">
1312    .\" </a>
1313    section on UTF-8 support
1314    .\"
1315    in the main
1316    .\" HREF
1317    \fBpcre\fP
1318    .\"
1319    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1320    the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains an invalid value,
1321    PCRE_ERROR_BADUTF8_OFFSET is returned.
1322  .P  .P
1323  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
1324  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 1463  The internal recursion limit, as specifi Line 1550  The internal recursion limit, as specifi
1550  field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the  field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the
1551  description above.  description above.
1552  .sp  .sp
   PCRE_ERROR_NULLWSLIMIT    (-22)  
 .sp  
 When a parenthesized subpattern that can match an empty substring is repeated  
 with an unbounded upper limit, the subject position at the start of the group  
 must be remembered, so that a test for an empty string can be made when the end  
 of the group is reached. The repetition loop is automatically terminated when  
 an empty string is matched.  
 .P  
 Some workspace is required for remembering the starting position. For most  
 capturing subpatterns, an internal recursive call of the match() function is  
 used, and in this case, the workspace is taken from the runtime stack. However,  
 for non-capturing subpatterns, this is not available. Instead, some fixed  
 workspace (taken from the top-level stack) is used. If it runs out, the  
 PCRE_ERROR_NULLWSLIMIT error is given. The size of the fixed workspace allows  
 for up to 1000 repetitions of a non-capturing subpattern that might match an  
 empty string. If this limit is a problem for you, you can sometimes get round  
 it by changing a non-capturing subpattern into a capturing one, but that will  
 increase the amount of runtime stack that is used.  
 .sp  
1553    PCRE_ERROR_BADNEWLINE     (-23)    PCRE_ERROR_BADNEWLINE     (-23)
1554  .sp  .sp
1555  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
1556  .P  .P
1557  Error numbers -16 to -20 are not used by \fBpcre_exec()\fP.  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
1558  .  .
1559  .  .
1560  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 1651  example is shown in the Line 1719  example is shown in the
1719  .\" HREF  .\" HREF
1720  \fBpcrepattern\fP  \fBpcrepattern\fP
1721  .\"  .\"
1722  documentation. When duplicates are present, \fBpcre_copy_named_substring()\fP  documentation.
1723  and \fBpcre_get_named_substring()\fP return the first substring corresponding  .P
1724  to the given name that is set. If none are set, an empty string is returned.  When duplicates are present, \fBpcre_copy_named_substring()\fP and
1725  The \fBpcre_get_stringnumber()\fP function returns one of the numbers that are  \fBpcre_get_named_substring()\fP return the first substring corresponding to
1726  associated with the name, but it is not defined which it is.  the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is
1727  .sp  returned; no data is returned. The \fBpcre_get_stringnumber()\fP function
1728    returns one of the numbers that are associated with the name, but it is not
1729    defined which it is.
1730    .P
1731  If you want to get full details of all captured substrings for a given name,  If you want to get full details of all captured substrings for a given name,
1732  you must use the \fBpcre_get_stringtable_entries()\fP function. The first  you must use the \fBpcre_get_stringtable_entries()\fP function. The first
1733  argument is the compiled pattern, and the second is the name. The third and  argument is the compiled pattern, and the second is the name. The third and
# Line 1881  Cambridge CB2 3QH, England. Line 1952  Cambridge CB2 3QH, England.
1952  .rs  .rs
1953  .sp  .sp
1954  .nf  .nf
1955  Last updated: 30 July 2007  Last updated: 11 September 2007
1956  Copyright (c) 1997-2007 University of Cambridge.  Copyright (c) 1997-2007 University of Cambridge.
1957  .fi  .fi
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