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revision 456 by ph10, Fri Oct 2 08:53:31 2009 UTC revision 510 by ph10, Sat Mar 27 17:45:29 2010 UTC
# Line 395  avoiding the use of the stack. Line 395  avoiding the use of the stack.
395  Either of the functions \fBpcre_compile()\fP or \fBpcre_compile2()\fP can be  Either of the functions \fBpcre_compile()\fP or \fBpcre_compile2()\fP can be
396  called to compile a pattern into an internal form. The only difference between  called to compile a pattern into an internal form. The only difference between
397  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,
398  \fIerrorcodeptr\fP, via which a numerical error code can be returned. To avoid  \fIerrorcodeptr\fP, via which a numerical error code can be returned. To avoid
399  too much repetition, we refer just to \fBpcre_compile()\fP below, but the  too much repetition, we refer just to \fBpcre_compile()\fP below, but the
400  information applies equally to \fBpcre_compile2()\fP.  information applies equally to \fBpcre_compile2()\fP.
401  .P  .P
402  The pattern is a C string terminated by a binary zero, and is passed in the  The pattern is a C string terminated by a binary zero, and is passed in the
# Line 421  within the pattern (see the detailed des Line 421  within the pattern (see the detailed des
421  .\"  .\"
422  documentation). For those options that can be different in different parts of  documentation). For those options that can be different in different parts of
423  the pattern, the contents of the \fIoptions\fP argument specifies their  the pattern, the contents of the \fIoptions\fP argument specifies their
424  settings at the start of compilation and execution. The PCRE_ANCHORED,  settings at the start of compilation and execution. The PCRE_ANCHORED,
425  PCRE_BSR_\fIxxx\fP, and PCRE_NEWLINE_\fIxxx\fP options can be set at the time  PCRE_BSR_\fIxxx\fP, and PCRE_NEWLINE_\fIxxx\fP options can be set at the time
426  of matching as well as at compile time.  of matching as well as at compile time.
427  .P  .P
# Line 747  out of use. To avoid confusion, they hav Line 747  out of use. To avoid confusion, they hav
747    57  \eg is not followed by a braced, angle-bracketed, or quoted    57  \eg is not followed by a braced, angle-bracketed, or quoted
748          name/number or by a plain number          name/number or by a plain number
749    58  a numbered reference must not be zero    58  a numbered reference must not be zero
750    59  (*VERB) with an argument is not supported    59  an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT)
751    60  (*VERB) not recognized    60  (*VERB) not recognized
752    61  number is too big    61  number is too big
753    62  subpattern name expected    62  subpattern name expected
754    63  digit expected after (?+    63  digit expected after (?+
755    64  ] is an invalid data character in JavaScript compatibility mode    64  ] is an invalid data character in JavaScript compatibility mode
756      65  different names for subpatterns of the same number are not allowed
757      66  (*MARK) must have an argument
758  .sp  .sp
759  The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may  The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
760  be used if the limits were changed when PCRE was built.  be used if the limits were changed when PCRE was built.
# Line 785  in the section on matching a pattern. Line 787  in the section on matching a pattern.
787  .P  .P
788  If studying the pattern does not produce any useful information,  If studying the pattern does not produce any useful information,
789  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program
790  wants to pass any of the other fields to \fBpcre_exec()\fP or  wants to pass any of the other fields to \fBpcre_exec()\fP or
791  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.
792  .P  .P
793  The second argument of \fBpcre_study()\fP contains option bits. At present, no  The second argument of \fBpcre_study()\fP contains option bits. At present, no
# Line 807  This is a typical call to \fBpcre_study\ Line 809  This is a typical call to \fBpcre_study\
809      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
810  .sp  .sp
811  Studying a pattern does two things: first, a lower bound for the length of  Studying a pattern does two things: first, a lower bound for the length of
812  subject string that is needed to match the pattern is computed. This does not  subject string that is needed to match the pattern is computed. This does not
813  mean that there are any strings of that length that match, but it does  mean that there are any strings of that length that match, but it does
814  guarantee that no shorter strings match. The value is used by  guarantee that no shorter strings match. The value is used by
815  \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP to avoid wasting time by trying to  \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP to avoid wasting time by trying to
816  match strings that are shorter than the lower bound. You can find out the value  match strings that are shorter than the lower bound. You can find out the value
817  in a calling program via the \fBpcre_fullinfo()\fP function.  in a calling program via the \fBpcre_fullinfo()\fP function.
818  .P  .P
819  Studying a pattern is also useful for non-anchored patterns that do not have a  Studying a pattern is also useful for non-anchored patterns that do not have a
820  single fixed starting character. A bitmap of possible starting bytes is  single fixed starting character. A bitmap of possible starting bytes is
821  created. This speeds up finding a position in the subject at which to start  created. This speeds up finding a position in the subject at which to start
822  matching.  matching.
823  .  .
824  .  .
# Line 1012  entry; both of these return an \fBint\fP Line 1014  entry; both of these return an \fBint\fP
1014  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first
1015  entry of the table (a pointer to \fBchar\fP). The first two bytes of each entry  entry of the table (a pointer to \fBchar\fP). The first two bytes of each entry
1016  are the number of the capturing parenthesis, most significant byte first. The  are the number of the capturing parenthesis, most significant byte first. The
1017  rest of the entry is the corresponding name, zero terminated. The names are in  rest of the entry is the corresponding name, zero terminated.
1018  alphabetical order. When PCRE_DUPNAMES is set, duplicate names are in order of  .P
1019  their parentheses numbers. For example, consider the following pattern (assume  The names are in alphabetical order. Duplicate names may appear if (?| is used
1020  PCRE_EXTENDED is set, so white space - including newlines - is ignored):  to create multiple groups with the same number, as described in the
1021    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1022    .\" </a>
1023    section on duplicate subpattern numbers
1024    .\"
1025    in the
1026    .\" HREF
1027    \fBpcrepattern\fP
1028    .\"
1029    page. Duplicate names for subpatterns with different numbers are permitted only
1030    if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the
1031    table in the order in which they were found in the pattern. In the absence of
1032    (?| this is the order of increasing number; when (?| is used this is not
1033    necessarily the case because later subpatterns may have lower numbers.
1034    .P
1035    As a simple example of the name/number table, consider the following pattern
1036    (assume PCRE_EXTENDED is set, so white space - including newlines - is
1037    ignored):
1038  .sp  .sp
1039  .\" JOIN  .\" JOIN
1040    (?<date> (?<year>(\ed\ed)?\ed\ed) -    (?<date> (?<year>(\ed\ed)?\ed\ed) -
# Line 1193  fields (not necessarily in this order): Line 1212  fields (not necessarily in this order):
1212    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1213    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1214    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1215      unsigned char **\fImark\fP;
1216  .sp  .sp
1217  The \fIflags\fP field is a bitmap that specifies which of the other fields  The \fIflags\fP field is a bitmap that specifies which of the other fields
1218  are set. The flag bits are:  are set. The flag bits are:
# Line 1202  are set. The flag bits are: Line 1222  are set. The flag bits are:
1222    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1223    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1224    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1225      PCRE_EXTRA_MARK
1226  .sp  .sp
1227  Other flag bits should be set to zero. The \fIstudy_data\fP field is set in the  Other flag bits should be set to zero. The \fIstudy_data\fP field is set in the
1228  \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with  \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with
# Line 1264  called. See the Line 1285  called. See the
1285  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1286  .\"  .\"
1287  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1288    .P
1289    If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must
1290    be set to point to a \fBchar *\fP variable. If the pattern contains any
1291    backtracking control verbs such as (*MARK:NAME), and the execution ends up with
1292    a name to pass back, a pointer to the name string (zero terminated) is placed
1293    in the variable pointed to by the \fImark\fP field. The names are within the
1294    compiled pattern; if you wish to retain such a name you must copy it before
1295    freeing the memory of a compiled pattern. If there is no name to pass back, the
1296    variable pointed to by the \fImark\fP field set to NULL. For details of the
1297    backtracking control verbs, see the section entitled
1298    .\" HTML <a href="pcrepattern#backtrackcontrol">
1299    .\" </a>
1300    "Backtracking control"
1301    .\"
1302    in the
1303    .\" HREF
1304    \fBpcrepattern\fP
1305    .\"
1306    documentation.
1307    .
1308  .  .
1309  .\" HTML <a name="execoptions"></a>  .\" HTML <a name="execoptions"></a>
1310  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
# Line 1354  valid, so PCRE searches further into the Line 1395  valid, so PCRE searches further into the
1395  .sp  .sp
1396    PCRE_NOTEMPTY_ATSTART    PCRE_NOTEMPTY_ATSTART
1397  .sp  .sp
1398  This is like PCRE_NOTEMPTY, except that an empty string match that is not at  This is like PCRE_NOTEMPTY, except that an empty string match that is not at
1399  the start of the subject is permitted. If the pattern is anchored, such a match  the start of the subject is permitted. If the pattern is anchored, such a match
1400  can occur only if the pattern contains \eK.  can occur only if the pattern contains \eK.
1401  .P  .P
# Line 1410  PCRE_NO_UTF8_CHECK is set, the effect of Line 1451  PCRE_NO_UTF8_CHECK is set, the effect of
1451  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
1452  UTF-8 character, is undefined. Your program may crash.  UTF-8 character, is undefined. Your program may crash.
1453  .sp  .sp
1454    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
1455    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
1456  .sp  .sp
1457  These options turn on the partial matching feature. For backwards  These options turn on the partial matching feature. For backwards
# Line 1617  documentation for details of partial mat Line 1658  documentation for details of partial mat
1658  .sp  .sp
1659  This code is no longer in use. It was formerly returned when the PCRE_PARTIAL  This code is no longer in use. It was formerly returned when the PCRE_PARTIAL
1660  option was used with a compiled pattern containing items that were not  option was used with a compiled pattern containing items that were not
1661  supported for partial matching. From release 8.00 onwards, there are no  supported for partial matching. From release 8.00 onwards, there are no
1662  restrictions on partial matching.  restrictions on partial matching.
1663  .sp  .sp
1664    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
# Line 1789  then call \fBpcre_copy_substring()\fP or Line 1830  then call \fBpcre_copy_substring()\fP or
1830  appropriate. \fBNOTE:\fP If PCRE_DUPNAMES is set and there are duplicate names,  appropriate. \fBNOTE:\fP If PCRE_DUPNAMES is set and there are duplicate names,
1831  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
1832  .P  .P
1833  \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple  \fBWarning:\fP If the pattern uses the (?| feature to set up multiple
1834  subpatterns with the same number, you cannot use names to distinguish them,  subpatterns with the same number, as described in the
1835  because names are not included in the compiled code. The matching process uses  .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1836  only numbers.  .\" </a>
1837    section on duplicate subpattern numbers
1838    .\"
1839    in the
1840    .\" HREF
1841    \fBpcrepattern\fP
1842    .\"
1843    page, you cannot use names to distinguish the different subpatterns, because
1844    names are not included in the compiled code. The matching process uses only
1845    numbers. For this reason, the use of different names for subpatterns of the
1846    same number causes an error at compile time.
1847  .  .
1848  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
1849  .rs  .rs
# Line 1802  only numbers. Line 1853  only numbers.
1853  .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);  .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
1854  .PP  .PP
1855  When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns  When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns
1856  are not required to be unique. Normally, patterns with duplicate names are such  are not required to be unique. (Duplicate names are always allowed for
1857  that in any one match, only one of the named subpatterns participates. An  subpatterns with the same number, created by using the (?| feature. Indeed, if
1858  example is shown in the  such subpatterns are named, they are required to use the same names.)
1859    .P
1860    Normally, patterns with duplicate names are such that in any one match, only
1861    one of the named subpatterns participates. An example is shown in the
1862  .\" HREF  .\" HREF
1863  \fBpcrepattern\fP  \fBpcrepattern\fP
1864  .\"  .\"
# Line 1868  a compiled pattern, using a matching alg Line 1922  a compiled pattern, using a matching alg
1922  just once, and does not backtrack. This has different characteristics to the  just once, and does not backtrack. This has different characteristics to the
1923  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
1924  patterns are not supported. Nevertheless, there are times when this kind of  patterns are not supported. Nevertheless, there are times when this kind of
1925  matching can be useful. For a discussion of the two matching algorithms, and a  matching can be useful. For a discussion of the two matching algorithms, and a
1926  list of features that \fBpcre_dfa_exec()\fP does not support, see the  list of features that \fBpcre_dfa_exec()\fP does not support, see the
1927  .\" HREF  .\" HREF
1928  \fBpcrematching\fP  \fBpcrematching\fP
# Line 1914  and PCRE_DFA_RESTART. All but the last f Line 1968  and PCRE_DFA_RESTART. All but the last f
1968  for \fBpcre_exec()\fP, so their description is not repeated here.  for \fBpcre_exec()\fP, so their description is not repeated here.
1969  .sp  .sp
1970    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
1971    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
1972  .sp  .sp
1973  These have the same general effect as they do for \fBpcre_exec()\fP, but the  These have the same general effect as they do for \fBpcre_exec()\fP, but the
1974  details are slightly different. When PCRE_PARTIAL_HARD is set for  details are slightly different. When PCRE_PARTIAL_HARD is set for
# Line 2045  Cambridge CB2 3QH, England. Line 2099  Cambridge CB2 3QH, England.
2099  .rs  .rs
2100  .sp  .sp
2101  .nf  .nf
2102  Last updated: 29 September 2009  Last updated: 26 March 2010
2103  Copyright (c) 1997-2009 University of Cambridge.  Copyright (c) 1997-2010 University of Cambridge.
2104  .fi  .fi

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