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revision 202 by ph10, Fri Aug 3 09:44:26 2007 UTC revision 231 by ph10, Tue Sep 11 11:15:33 2007 UTC
# Line 243  by the caller to a "callout" function, w Line 243  by the caller to a "callout" function, w
243  points during a matching operation. Details are given in the  points during a matching operation. Details are given in the
244  <a href="pcrecallout.html"><b>pcrecallout</b></a>  <a href="pcrecallout.html"><b>pcrecallout</b></a>
245  documentation.  documentation.
246  </P>  <a name="newlines"></a></P>
247  <br><a name="SEC3" href="#TOC1">NEWLINES</a><br>  <br><a name="SEC3" href="#TOC1">NEWLINES</a><br>
248  <P>  <P>
249  PCRE supports five different conventions for indicating line breaks in  PCRE supports five different conventions for indicating line breaks in
# Line 262  default can be overridden, either when a Line 262  default can be overridden, either when a
262  matched.  matched.
263  </P>  </P>
264  <P>  <P>
265    At compile time, the newline convention can be specified by the <i>options</i>
266    argument of <b>pcre_compile()</b>, or it can be specified by special text at the
267    start of the pattern itself; this overrides any other settings. See the
268    <a href="pcrepattern.html"><b>pcrepattern</b></a>
269    page for details of the special character sequences.
270    </P>
271    <P>
272  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
273  pair of characters that indicate a line break". The choice of newline  pair of characters that indicate a line break". The choice of newline
274  convention affects the handling of the dot, circumflex, and dollar  convention affects the handling of the dot, circumflex, and dollar
275  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
276  recognized line ending sequence, the match position advancement for a  recognized line ending sequence, the match position advancement for a
277  non-anchored pattern. The choice of newline convention does not affect the  non-anchored pattern. There is more detail about this in the
278  interpretation of the \n or \r escape sequences.  <a href="#execoptions">section on <b>pcre_exec()</b> options</a>
279    below.
280    </P>
281    <P>
282    The choice of newline convention does not affect the interpretation of
283    the \n or \r escape sequences, nor does it affect what \R matches, which is
284    controlled in a similar way, but by separate options.
285  </P>  </P>
286  <br><a name="SEC4" href="#TOC1">MULTITHREADING</a><br>  <br><a name="SEC4" href="#TOC1">MULTITHREADING</a><br>
287  <P>  <P>
# Line 323  that is recognized as meaning "newline". Line 336  that is recognized as meaning "newline".
336  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
337  default should normally be the standard sequence for your operating system.  default should normally be the standard sequence for your operating system.
338  <pre>  <pre>
339      PCRE_CONFIG_BSR
340    </pre>
341    The output is an integer whose value indicates what character sequences the \R
342    escape sequence matches by default. A value of 0 means that \R matches any
343    Unicode line ending sequence; a value of 1 means that \R matches only CR, LF,
344    or CRLF. The default can be overridden when a pattern is compiled or matched.
345    <pre>
346    PCRE_CONFIG_LINK_SIZE    PCRE_CONFIG_LINK_SIZE
347  </pre>  </pre>
348  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 458  facility, see the Line 478  facility, see the
478  <a href="pcrecallout.html"><b>pcrecallout</b></a>  <a href="pcrecallout.html"><b>pcrecallout</b></a>
479  documentation.  documentation.
480  <pre>  <pre>
481      PCRE_BSR_ANYCRLF
482      PCRE_BSR_UNICODE
483    </pre>
484    These options (which are mutually exclusive) control what the \R escape
485    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
486    match any Unicode newline sequence. The default is specified when PCRE is
487    built. It can be overridden from within the pattern, or by setting an option
488    when a compiled pattern is matched.
489    <pre>
490    PCRE_CASELESS    PCRE_CASELESS
491  </pre>  </pre>
492  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 613  page. Line 642  page.
642    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
643  </pre>  </pre>
644  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
645  automatically checked. If an invalid UTF-8 sequence of bytes is found,  automatically checked. There is a discussion about the
646  <b>pcre_compile()</b> returns an error. If you already know that your pattern is  <a href="pcre.html#utf8strings">validity of UTF-8 strings</a>
647  valid, and you want to skip this check for performance reasons, you can set the  in the main
648  PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid  <a href="pcre.html"><b>pcre</b></a>
649  UTF-8 string as a pattern is undefined. It may cause your program to crash.  page. If an invalid UTF-8 sequence of bytes is found, <b>pcre_compile()</b>
650  Note that this option can also be passed to <b>pcre_exec()</b> and  returns an error. If you already know that your pattern is valid, and you want
651  <b>pcre_dfa_exec()</b>, to suppress the UTF-8 validity checking of subject  to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
652  strings.  option. When it is set, the effect of passing an invalid UTF-8 string as a
653    pattern is undefined. It may cause your program to crash. Note that this option
654    can also be passed to <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>, to suppress
655    the UTF-8 validity checking of subject strings.
656  </P>  </P>
657  <br><a name="SEC8" href="#TOC1">COMPILATION ERROR CODES</a><br>  <br><a name="SEC8" href="#TOC1">COMPILATION ERROR CODES</a><br>
658  <P>  <P>
# Line 685  out of use. To avoid confusion, they hav Line 717  out of use. To avoid confusion, they hav
717    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern not found
718    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
719    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
720    56  inconsistent NEWLINE options"    56  inconsistent NEWLINE options
721    57  \g is not followed by a braced name or an optionally braced    57  \g is not followed by a braced name or an optionally braced
722          non-zero number          non-zero number
723    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 891  table indicating a fixed set of bytes fo Line 923  table indicating a fixed set of bytes fo
923  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
924  fourth argument should point to an <b>unsigned char *</b> variable.  fourth argument should point to an <b>unsigned char *</b> variable.
925  <pre>  <pre>
926      PCRE_INFO_HASCRORLF
927    </pre>
928    Return 1 if the pattern contains any explicit matches for CR or LF characters,
929    otherwise 0. The fourth argument should point to an <b>int</b> variable.
930    <pre>
931    PCRE_INFO_JCHANGED    PCRE_INFO_JCHANGED
932  </pre>  </pre>
933  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 1173  the external tables might be at a differ Line 1210  the external tables might be at a differ
1210  called. See the  called. See the
1211  <a href="pcreprecompile.html"><b>pcreprecompile</b></a>  <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
1212  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1213  </P>  <a name="execoptions"></a></P>
1214  <br><b>  <br><b>
1215  Option bits for <b>pcre_exec()</b>  Option bits for <b>pcre_exec()</b>
1216  </b><br>  </b><br>
# Line 1189  matching position. If a pattern was comp Line 1226  matching position. If a pattern was comp
1226  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
1227  matching time.  matching time.
1228  <pre>  <pre>
1229      PCRE_BSR_ANYCRLF
1230      PCRE_BSR_UNICODE
1231    </pre>
1232    These options (which are mutually exclusive) control what the \R escape
1233    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1234    match any Unicode newline sequence. These options override the choice that was
1235    made or defaulted when the pattern was compiled.
1236    <pre>
1237    PCRE_NEWLINE_CR    PCRE_NEWLINE_CR
1238    PCRE_NEWLINE_LF    PCRE_NEWLINE_LF
1239    PCRE_NEWLINE_CRLF    PCRE_NEWLINE_CRLF
# Line 1200  the pattern was compiled. For details, s Line 1245  the pattern was compiled. For details, s
1245  <b>pcre_compile()</b> above. During matching, the newline choice affects the  <b>pcre_compile()</b> above. During matching, the newline choice affects the
1246  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1247  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
1248  pattern. When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is  pattern.
1249  set, and a match attempt fails when the current position is at a CRLF sequence,  </P>
1250  the match position is advanced by two characters instead of one, in other  <P>
1251  words, to after the CRLF.  When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a
1252    match attempt for an unanchored pattern fails when the current position is at a
1253    CRLF sequence, and the pattern contains no explicit matches for CR or LF
1254    characters, the match position is advanced by two characters instead of one, in
1255    other words, to after the CRLF.
1256    </P>
1257    <P>
1258    The above rule is a compromise that makes the most common cases work as
1259    expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1260    set), it does not match the string "\r\nA" because, after failing at the
1261    start, it skips both the CR and the LF before retrying. However, the pattern
1262    [\r\n]A does match that string, because it contains an explicit CR or LF
1263    reference, and so advances only by one character after the first failure.
1264    </P>
1265    <P>
1266    An explicit match for CR of LF is either a literal appearance of one of those
1267    characters, or one of the \r or \n escape sequences. Implicit matches such as
1268    [^X] do not count, nor does \s (which includes CR and LF in the characters
1269    that it matches).
1270    </P>
1271    <P>
1272    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1273    valid newline sequence and explicit \r or \n escapes appear in the pattern.
1274  <pre>  <pre>
1275    PCRE_NOTBOL    PCRE_NOTBOL
1276  </pre>  </pre>
# Line 1247  code that demonstrates how to do this in Line 1314  code that demonstrates how to do this in
1314  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
1315  string is automatically checked when <b>pcre_exec()</b> is subsequently called.  string is automatically checked when <b>pcre_exec()</b> is subsequently called.
1316  The value of <i>startoffset</i> is also checked to ensure that it points to the  The value of <i>startoffset</i> is also checked to ensure that it points to the
1317  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
1318  <b>pcre_exec()</b> returns the error PCRE_ERROR_BADUTF8. If <i>startoffset</i>  strings in the
1319  contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.  <a href="pcre.html#utf8strings">section on UTF-8 support</a>
1320    in the main
1321    <a href="pcre.html"><b>pcre</b></a>
1322    page. If an invalid UTF-8 sequence of bytes is found, <b>pcre_exec()</b> returns
1323    the error PCRE_ERROR_BADUTF8. If <i>startoffset</i> contains an invalid value,
1324    PCRE_ERROR_BADUTF8_OFFSET is returned.
1325  </P>  </P>
1326  <P>  <P>
1327  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
# Line 1653  are not required to be unique. Normally, Line 1725  are not required to be unique. Normally,
1725  that in any one match, only one of the named subpatterns participates. An  that in any one match, only one of the named subpatterns participates. An
1726  example is shown in the  example is shown in the
1727  <a href="pcrepattern.html"><b>pcrepattern</b></a>  <a href="pcrepattern.html"><b>pcrepattern</b></a>
1728  documentation. When duplicates are present, <b>pcre_copy_named_substring()</b>  documentation.
1729  and <b>pcre_get_named_substring()</b> return the first substring corresponding  </P>
1730  to the given name that is set. If none are set, an empty string is returned.  <P>
1731  The <b>pcre_get_stringnumber()</b> function returns one of the numbers that are  When duplicates are present, <b>pcre_copy_named_substring()</b> and
1732  associated with the name, but it is not defined which it is.  <b>pcre_get_named_substring()</b> return the first substring corresponding to
1733  <br>  the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is
1734  <br>  returned; no data is returned. The <b>pcre_get_stringnumber()</b> function
1735    returns one of the numbers that are associated with the name, but it is not
1736    defined which it is.
1737    </P>
1738    <P>
1739  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,
1740  you must use the <b>pcre_get_stringtable_entries()</b> function. The first  you must use the <b>pcre_get_stringtable_entries()</b> function. The first
1741  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 1871  Cambridge CB2 3QH, England. Line 1947  Cambridge CB2 3QH, England.
1947  </P>  </P>
1948  <br><a name="SEC22" href="#TOC1">REVISION</a><br>  <br><a name="SEC22" href="#TOC1">REVISION</a><br>
1949  <P>  <P>
1950  Last updated: 30 July 2007  Last updated: 11 September 2007
1951  <br>  <br>
1952  Copyright &copy; 1997-2007 University of Cambridge.  Copyright &copy; 1997-2007 University of Cambridge.
1953  <br>  <br>

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