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revision 456 by ph10, Fri Oct 2 08:53:31 2009 UTC revision 518 by ph10, Tue May 18 15:47:01 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 553  set, any backslash in a pattern that is Line 553  set, any backslash in a pattern that is
553  special meaning causes an error, thus reserving these combinations for future  special meaning causes an error, thus reserving these combinations for future
554  expansion. By default, as in Perl, a backslash followed by a letter with no  expansion. By default, as in Perl, a backslash followed by a letter with no
555  special meaning is treated as a literal. (Perl can, however, be persuaded to  special meaning is treated as a literal. (Perl can, however, be persuaded to
556  give a warning for this.) There are at present no other features controlled by  give an error for this, by running it with the -w option.) There are at present
557  this option. It can also be set by a (?X) option setting within a pattern.  no other features controlled by this option. It can also be set by a (?X)
558    option setting within a pattern.
559  .sp  .sp
560    PCRE_FIRSTLINE    PCRE_FIRSTLINE
561  .sp  .sp
# Line 635  were followed by ?: but named parenthese Line 636  were followed by ?: but named parenthese
636  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
637  in Perl.  in Perl.
638  .sp  .sp
639      PCRE_UCP
640    .sp
641    This option changes the way PCRE processes \eb, \ed, \es, \ew, and some of the
642    POSIX character classes. By default, only ASCII characters are recognized, but
643    if PCRE_UCP is set, Unicode properties are used instead to classify characters.
644    More details are given in the section on
645    .\" HTML <a href="pcre.html#genericchartypes">
646    .\" </a>
647    generic character types
648    .\"
649    in the
650    .\" HREF
651    \fBpcrepattern\fP
652    .\"
653    page. If you set PCRE_UCP, matching one of the items it affects takes much
654    longer. The option is available only if PCRE has been compiled with Unicode
655    property support.
656    .sp
657    PCRE_UNGREEDY    PCRE_UNGREEDY
658  .sp  .sp
659  This option inverts the "greediness" of the quantifiers so that they are not  This option inverts the "greediness" of the quantifiers so that they are not
# Line 747  out of use. To avoid confusion, they hav Line 766  out of use. To avoid confusion, they hav
766    57  \eg is not followed by a braced, angle-bracketed, or quoted    57  \eg is not followed by a braced, angle-bracketed, or quoted
767          name/number or by a plain number          name/number or by a plain number
768    58  a numbered reference must not be zero    58  a numbered reference must not be zero
769    59  (*VERB) with an argument is not supported    59  an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT)
770    60  (*VERB) not recognized    60  (*VERB) not recognized
771    61  number is too big    61  number is too big
772    62  subpattern name expected    62  subpattern name expected
773    63  digit expected after (?+    63  digit expected after (?+
774    64  ] is an invalid data character in JavaScript compatibility mode    64  ] is an invalid data character in JavaScript compatibility mode
775      65  different names for subpatterns of the same number are not allowed
776      66  (*MARK) must have an argument
777      67  this version of PCRE is not compiled with PCRE_UCP support
778  .sp  .sp
779  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
780  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 807  in the section on matching a pattern.
807  .P  .P
808  If studying the pattern does not produce any useful information,  If studying the pattern does not produce any useful information,
809  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program
810  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
811  \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.
812  .P  .P
813  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 829  This is a typical call to \fBpcre_study\
829      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
830  .sp  .sp
831  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
832  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
833  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
834  guarantee that no shorter strings match. The value is used by  guarantee that no shorter strings match. The value is used by
835  \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
836  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
837  in a calling program via the \fBpcre_fullinfo()\fP function.  in a calling program via the \fBpcre_fullinfo()\fP function.
838  .P  .P
839  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
840  single fixed starting character. A bitmap of possible starting bytes is  single fixed starting character. A bitmap of possible starting bytes is
841  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
842  matching.  matching.
843  .  .
844  .  .
# Line 827  matching. Line 849  matching.
849  PCRE handles caseless matching, and determines whether characters are letters,  PCRE handles caseless matching, and determines whether characters are letters,
850  digits, or whatever, by reference to a set of tables, indexed by character  digits, or whatever, by reference to a set of tables, indexed by character
851  value. When running in UTF-8 mode, this applies only to characters with codes  value. When running in UTF-8 mode, this applies only to characters with codes
852  less than 128. Higher-valued codes never match escapes such as \ew or \ed, but  less than 128. By default, higher-valued codes never match escapes such as \ew
853  can be tested with \ep if PCRE is built with Unicode character property  or \ed, but they can be tested with \ep if PCRE is built with Unicode character
854  support. The use of locales with Unicode is discouraged. If you are handling  property support. Alternatively, the PCRE_UCP option can be set at compile
855  characters with codes greater than 128, you should either use UTF-8 and  time; this causes \ew and friends to use Unicode property support instead of
856  Unicode, or use locales, but not try to mix the two.  built-in tables. The use of locales with Unicode is discouraged. If you are
857    handling characters with codes greater than 128, you should either use UTF-8
858    and Unicode, or use locales, but not try to mix the two.
859  .P  .P
860  PCRE contains an internal set of tables that are used when the final argument  PCRE contains an internal set of tables that are used when the final argument
861  of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.  of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.
# Line 1012  entry; both of these return an \fBint\fP Line 1036  entry; both of these return an \fBint\fP
1036  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
1037  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
1038  are the number of the capturing parenthesis, most significant byte first. The  are the number of the capturing parenthesis, most significant byte first. The
1039  rest of the entry is the corresponding name, zero terminated. The names are in  rest of the entry is the corresponding name, zero terminated.
1040  alphabetical order. When PCRE_DUPNAMES is set, duplicate names are in order of  .P
1041  their parentheses numbers. For example, consider the following pattern (assume  The names are in alphabetical order. Duplicate names may appear if (?| is used
1042  PCRE_EXTENDED is set, so white space - including newlines - is ignored):  to create multiple groups with the same number, as described in the
1043    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1044    .\" </a>
1045    section on duplicate subpattern numbers
1046    .\"
1047    in the
1048    .\" HREF
1049    \fBpcrepattern\fP
1050    .\"
1051    page. Duplicate names for subpatterns with different numbers are permitted only
1052    if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the
1053    table in the order in which they were found in the pattern. In the absence of
1054    (?| this is the order of increasing number; when (?| is used this is not
1055    necessarily the case because later subpatterns may have lower numbers.
1056    .P
1057    As a simple example of the name/number table, consider the following pattern
1058    (assume PCRE_EXTENDED is set, so white space - including newlines - is
1059    ignored):
1060  .sp  .sp
1061  .\" JOIN  .\" JOIN
1062    (?<date> (?<year>(\ed\ed)?\ed\ed) -    (?<date> (?<year>(\ed\ed)?\ed\ed) -
# Line 1193  fields (not necessarily in this order): Line 1234  fields (not necessarily in this order):
1234    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1235    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1236    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1237      unsigned char **\fImark\fP;
1238  .sp  .sp
1239  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
1240  are set. The flag bits are:  are set. The flag bits are:
# Line 1202  are set. The flag bits are: Line 1244  are set. The flag bits are:
1244    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1245    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1246    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1247      PCRE_EXTRA_MARK
1248  .sp  .sp
1249  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
1250  \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 1307  called. See the
1307  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1308  .\"  .\"
1309  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1310    .P
1311    If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must
1312    be set to point to a \fBchar *\fP variable. If the pattern contains any
1313    backtracking control verbs such as (*MARK:NAME), and the execution ends up with
1314    a name to pass back, a pointer to the name string (zero terminated) is placed
1315    in the variable pointed to by the \fImark\fP field. The names are within the
1316    compiled pattern; if you wish to retain such a name you must copy it before
1317    freeing the memory of a compiled pattern. If there is no name to pass back, the
1318    variable pointed to by the \fImark\fP field set to NULL. For details of the
1319    backtracking control verbs, see the section entitled
1320    .\" HTML <a href="pcrepattern#backtrackcontrol">
1321    .\" </a>
1322    "Backtracking control"
1323    .\"
1324    in the
1325    .\" HREF
1326    \fBpcrepattern\fP
1327    .\"
1328    documentation.
1329    .
1330  .  .
1331  .\" HTML <a name="execoptions"></a>  .\" HTML <a name="execoptions"></a>
1332  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
# Line 1354  valid, so PCRE searches further into the Line 1417  valid, so PCRE searches further into the
1417  .sp  .sp
1418    PCRE_NOTEMPTY_ATSTART    PCRE_NOTEMPTY_ATSTART
1419  .sp  .sp
1420  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
1421  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
1422  can occur only if the pattern contains \eK.  can occur only if the pattern contains \eK.
1423  .P  .P
# Line 1410  PCRE_NO_UTF8_CHECK is set, the effect of Line 1473  PCRE_NO_UTF8_CHECK is set, the effect of
1473  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
1474  UTF-8 character, is undefined. Your program may crash.  UTF-8 character, is undefined. Your program may crash.
1475  .sp  .sp
1476    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
1477    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
1478  .sp  .sp
1479  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 1680  documentation for details of partial mat
1680  .sp  .sp
1681  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
1682  option was used with a compiled pattern containing items that were not  option was used with a compiled pattern containing items that were not
1683  supported for partial matching. From release 8.00 onwards, there are no  supported for partial matching. From release 8.00 onwards, there are no
1684  restrictions on partial matching.  restrictions on partial matching.
1685  .sp  .sp
1686    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
# Line 1789  then call \fBpcre_copy_substring()\fP or Line 1852  then call \fBpcre_copy_substring()\fP or
1852  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,
1853  the behaviour may not be what you want (see the next section).  the behaviour may not be what you want (see the next section).
1854  .P  .P
1855  \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple  \fBWarning:\fP If the pattern uses the (?| feature to set up multiple
1856  subpatterns with the same number, you cannot use names to distinguish them,  subpatterns with the same number, as described in the
1857  because names are not included in the compiled code. The matching process uses  .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1858  only numbers.  .\" </a>
1859    section on duplicate subpattern numbers
1860    .\"
1861    in the
1862    .\" HREF
1863    \fBpcrepattern\fP
1864    .\"
1865    page, you cannot use names to distinguish the different subpatterns, because
1866    names are not included in the compiled code. The matching process uses only
1867    numbers. For this reason, the use of different names for subpatterns of the
1868    same number causes an error at compile time.
1869  .  .
1870  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
1871  .rs  .rs
# Line 1802  only numbers. Line 1875  only numbers.
1875  .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);  .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
1876  .PP  .PP
1877  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
1878  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
1879  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
1880  example is shown in the  such subpatterns are named, they are required to use the same names.)
1881    .P
1882    Normally, patterns with duplicate names are such that in any one match, only
1883    one of the named subpatterns participates. An example is shown in the
1884  .\" HREF  .\" HREF
1885  \fBpcrepattern\fP  \fBpcrepattern\fP
1886  .\"  .\"
# Line 1868  a compiled pattern, using a matching alg Line 1944  a compiled pattern, using a matching alg
1944  just once, and does not backtrack. This has different characteristics to the  just once, and does not backtrack. This has different characteristics to the
1945  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
1946  patterns are not supported. Nevertheless, there are times when this kind of  patterns are not supported. Nevertheless, there are times when this kind of
1947  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
1948  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
1949  .\" HREF  .\" HREF
1950  \fBpcrematching\fP  \fBpcrematching\fP
# Line 1914  and PCRE_DFA_RESTART. All but the last f Line 1990  and PCRE_DFA_RESTART. All but the last f
1990  for \fBpcre_exec()\fP, so their description is not repeated here.  for \fBpcre_exec()\fP, so their description is not repeated here.
1991  .sp  .sp
1992    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
1993    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
1994  .sp  .sp
1995  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
1996  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 2121  Cambridge CB2 3QH, England.
2121  .rs  .rs
2122  .sp  .sp
2123  .nf  .nf
2124  Last updated: 29 September 2009  Last updated: 16 May 2010
2125  Copyright (c) 1997-2009 University of Cambridge.  Copyright (c) 1997-2010 University of Cambridge.
2126  .fi  .fi

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