/[pcre]/code/trunk/doc/pcreapi.3
ViewVC logotype

Diff of /code/trunk/doc/pcreapi.3

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 461 by ph10, Mon Oct 5 10:59:35 2009 UTC revision 546 by ph10, Sun Jun 20 15:44:12 2010 UTC
# Line 132  an application that uses PCRE. The heade Line 132  an application that uses PCRE. The heade
132  and PCRE_MINOR to contain the major and minor release numbers for the library.  and PCRE_MINOR to contain the major and minor release numbers for the library.
133  Applications can use these to include support for different releases of PCRE.  Applications can use these to include support for different releases of PCRE.
134  .P  .P
135    In a Windows environment, if you want to statically link an application program
136    against a non-dll \fBpcre.a\fP file, you must define PCRE_STATIC before
137    including \fBpcre.h\fP or \fBpcrecpp.h\fP, because otherwise the
138    \fBpcre_malloc()\fP and \fBpcre_free()\fP exported functions will be declared
139    \fB__declspec(dllimport)\fP, with unwanted results.
140    .P
141  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,
142  and \fBpcre_exec()\fP are used for compiling and matching regular expressions  and \fBpcre_exec()\fP are used for compiling and matching regular expressions
143  in a Perl-compatible manner. A sample program that demonstrates the simplest  in a Perl-compatible manner. A sample program that demonstrates the simplest
# Line 553  set, any backslash in a pattern that is Line 559  set, any backslash in a pattern that is
559  special meaning causes an error, thus reserving these combinations for future  special meaning causes an error, thus reserving these combinations for future
560  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
561  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
562  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
563  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)
564    option setting within a pattern.
565  .sp  .sp
566    PCRE_FIRSTLINE    PCRE_FIRSTLINE
567  .sp  .sp
# Line 635  were followed by ?: but named parenthese Line 642  were followed by ?: but named parenthese
642  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
643  in Perl.  in Perl.
644  .sp  .sp
645      PCRE_UCP
646    .sp
647    This option changes the way PCRE processes \eb, \ed, \es, \ew, and some of the
648    POSIX character classes. By default, only ASCII characters are recognized, but
649    if PCRE_UCP is set, Unicode properties are used instead to classify characters.
650    More details are given in the section on
651    .\" HTML <a href="pcre.html#genericchartypes">
652    .\" </a>
653    generic character types
654    .\"
655    in the
656    .\" HREF
657    \fBpcrepattern\fP
658    .\"
659    page. If you set PCRE_UCP, matching one of the items it affects takes much
660    longer. The option is available only if PCRE has been compiled with Unicode
661    property support.
662    .sp
663    PCRE_UNGREEDY    PCRE_UNGREEDY
664  .sp  .sp
665  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 740  out of use. To avoid confusion, they hav Line 765  out of use. To avoid confusion, they hav
765    50  [this code is not in use]    50  [this code is not in use]
766    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 (not in UTF-8 mode)
767    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
768    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern
769            not found
770    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
771    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
772    56  inconsistent NEWLINE options    56  inconsistent NEWLINE options
773    57  \eg is not followed by a braced, angle-bracketed, or quoted    57  \eg is not followed by a braced, angle-bracketed, or quoted
774          name/number or by a plain number          name/number or by a plain number
775    58  a numbered reference must not be zero    58  a numbered reference must not be zero
776    59  (*VERB) with an argument is not supported    59  an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT)
777    60  (*VERB) not recognized    60  (*VERB) not recognized
778    61  number is too big    61  number is too big
779    62  subpattern name expected    62  subpattern name expected
780    63  digit expected after (?+    63  digit expected after (?+
781    64  ] is an invalid data character in JavaScript compatibility mode    64  ] is an invalid data character in JavaScript compatibility mode
782      65  different names for subpatterns of the same number are
783            not allowed
784      66  (*MARK) must have an argument
785      67  this version of PCRE is not compiled with PCRE_UCP support
786  .sp  .sp
787  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
788  be used if the limits were changed when PCRE was built.  be used if the limits were changed when PCRE was built.
# Line 827  matching. Line 857  matching.
857  PCRE handles caseless matching, and determines whether characters are letters,  PCRE handles caseless matching, and determines whether characters are letters,
858  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
859  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
860  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
861  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
862  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
863  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
864  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
865    handling characters with codes greater than 128, you should either use UTF-8
866    and Unicode, or use locales, but not try to mix the two.
867  .P  .P
868  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
869  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 1210  fields (not necessarily in this order): Line 1242  fields (not necessarily in this order):
1242    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1243    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1244    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1245      unsigned char **\fImark\fP;
1246  .sp  .sp
1247  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
1248  are set. The flag bits are:  are set. The flag bits are:
# Line 1219  are set. The flag bits are: Line 1252  are set. The flag bits are:
1252    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1253    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1254    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1255      PCRE_EXTRA_MARK
1256  .sp  .sp
1257  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
1258  \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 1281  called. See the Line 1315  called. See the
1315  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1316  .\"  .\"
1317  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1318    .P
1319    If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must
1320    be set to point to a \fBchar *\fP variable. If the pattern contains any
1321    backtracking control verbs such as (*MARK:NAME), and the execution ends up with
1322    a name to pass back, a pointer to the name string (zero terminated) is placed
1323    in the variable pointed to by the \fImark\fP field. The names are within the
1324    compiled pattern; if you wish to retain such a name you must copy it before
1325    freeing the memory of a compiled pattern. If there is no name to pass back, the
1326    variable pointed to by the \fImark\fP field set to NULL. For details of the
1327    backtracking control verbs, see the section entitled
1328    .\" HTML <a href="pcrepattern#backtrackcontrol">
1329    .\" </a>
1330    "Backtracking control"
1331    .\"
1332    in the
1333    .\" HREF
1334    \fBpcrepattern\fP
1335    .\"
1336    documentation.
1337    .
1338  .  .
1339  .\" HTML <a name="execoptions"></a>  .\" HTML <a name="execoptions"></a>
1340  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
# Line 1391  sample program. Line 1445  sample program.
1445    PCRE_NO_START_OPTIMIZE    PCRE_NO_START_OPTIMIZE
1446  .sp  .sp
1447  There are a number of optimizations that \fBpcre_exec()\fP uses at the start of  There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1448  a match, in order to speed up the process. For example, if it is known that a  a match, in order to speed up the process. For example, if it is known that an
1449  match must start with a specific character, it searches the subject for that  unanchored match must start with a specific character, it searches the subject
1450  character, and fails immediately if it cannot find it, without actually running  for that character, and fails immediately if it cannot find it, without
1451  the main matching function. When callouts are in use, these optimizations can  actually running the main matching function. This means that a special item
1452  cause them to be skipped. This option disables the "start-up" optimizations,  such as (*COMMIT) at the start of a pattern is not considered until after a
1453  causing performance to suffer, but ensuring that the callouts do occur.  suitable starting point for the match has been found. When callouts or (*MARK)
1454    items are in use, these "start-up" optimizations can cause them to be skipped
1455    if the pattern is never actually used. The start-up optimizations are in effect
1456    a pre-scan of the subject that takes place before the pattern is run.
1457    .P
1458    The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1459    causing performance to suffer, but ensuring that in cases where the result is
1460    "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
1461    are considered at every possible starting position in the subject string.
1462    Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
1463    Consider the pattern
1464    .sp
1465      (*COMMIT)ABC
1466    .sp
1467    When this is compiled, PCRE records the fact that a match must start with the
1468    character "A". Suppose the subject string is "DEFABC". The start-up
1469    optimization scans along the subject, finds "A" and runs the first match
1470    attempt from there. The (*COMMIT) item means that the pattern must match the
1471    current starting position, which in this case, it does. However, if the same
1472    match is run with PCRE_NO_START_OPTIMIZE set, the initial scan along the
1473    subject string does not happen. The first match attempt is run starting from
1474    "D" and when this fails, (*COMMIT) prevents any further matches being tried, so
1475    the overall result is "no match". If the pattern is studied, more start-up
1476    optimizations may be used. For example, a minimum length for the subject may be
1477    recorded. Consider the pattern
1478    .sp
1479      (*MARK:A)(X|Y)
1480    .sp
1481    The minimum length for a match is one character. If the subject is "ABC", there
1482    will be attempts to match "ABC", "BC", "C", and then finally an empty string.
1483    If the pattern is studied, the final attempt does not take place, because PCRE
1484    knows that the subject is too short, and so the (*MARK) is never encountered.
1485    In this case, studying the pattern does not affect the overall match result,
1486    which is still "no match", but it does affect the auxiliary information that is
1487    returned.
1488  .sp  .sp
1489    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1490  .sp  .sp
# Line 1591  If a pattern contains back references, b Line 1679  If a pattern contains back references, b
1679  gets a block of memory at the start of matching to use for this purpose. If the  gets a block of memory at the start of matching to use for this purpose. If the
1680  call via \fBpcre_malloc()\fP fails, this error is given. The memory is  call via \fBpcre_malloc()\fP fails, this error is given. The memory is
1681  automatically freed at the end of matching.  automatically freed at the end of matching.
1682    .P
1683    This error is also given if \fBpcre_stack_malloc()\fP fails in
1684    \fBpcre_exec()\fP. This can happen only when PCRE has been compiled with
1685    \fB--disable-stack-for-recursion\fP.
1686  .sp  .sp
1687    PCRE_ERROR_NOSUBSTRING    (-7)    PCRE_ERROR_NOSUBSTRING    (-7)
1688  .sp  .sp
# Line 1939  Here is an example of a simple call to \ Line 2031  Here is an example of a simple call to \
2031  The unused bits of the \fIoptions\fP argument for \fBpcre_dfa_exec()\fP must be  The unused bits of the \fIoptions\fP argument for \fBpcre_dfa_exec()\fP must be
2032  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,
2033  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
2034  PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST,  PCRE_NO_UTF8_CHECK, PCRE_BSR_ANYCRLF, PCRE_BSR_UNICODE, PCRE_NO_START_OPTIMIZE,
2035  and PCRE_DFA_RESTART. All but the last four of these are exactly the same as  PCRE_PARTIAL_HARD, PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART.
2036  for \fBpcre_exec()\fP, so their description is not repeated here.  All but the last four of these are exactly the same as for \fBpcre_exec()\fP,
2037    so their description is not repeated here.
2038  .sp  .sp
2039    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
2040    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
# Line 2075  Cambridge CB2 3QH, England. Line 2168  Cambridge CB2 3QH, England.
2168  .rs  .rs
2169  .sp  .sp
2170  .nf  .nf
2171  Last updated: 03 October 2009  Last updated: 20 June 2010
2172  Copyright (c) 1997-2009 University of Cambridge.  Copyright (c) 1997-2010 University of Cambridge.
2173  .fi  .fi

Legend:
Removed from v.461  
changed lines
  Added in v.546

  ViewVC Help
Powered by ViewVC 1.1.5