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revision 457 by ph10, Sat Oct 3 16:24:08 2009 UTC revision 566 by ph10, Wed Nov 3 18:32:55 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 395  avoiding the use of the stack. Line 401  avoiding the use of the stack.
401  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
402  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
403  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,
404  \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
405  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
406  information applies equally to \fBpcre_compile2()\fP.  information applies equally to \fBpcre_compile2()\fP.
407  .P  .P
408  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 427  within the pattern (see the detailed des
427  .\"  .\"
428  documentation). For those options that can be different in different parts of  documentation). For those options that can be different in different parts of
429  the pattern, the contents of the \fIoptions\fP argument specifies their  the pattern, the contents of the \fIoptions\fP argument specifies their
430  settings at the start of compilation and execution. The PCRE_ANCHORED,  settings at the start of compilation and execution. The PCRE_ANCHORED,
431  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
432  of matching as well as at compile time.  of matching as well as at compile time.
433  .P  .P
# 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 785  in the section on matching a pattern. Line 815  in the section on matching a pattern.
815  .P  .P
816  If studying the pattern does not produce any useful information,  If studying the pattern does not produce any useful information,
817  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program
818  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
819  \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.
820  .P  .P
821  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 837  This is a typical call to \fBpcre_study\
837      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
838  .sp  .sp
839  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
840  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
841  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
842  guarantee that no shorter strings match. The value is used by  guarantee that no shorter strings match. The value is used by
843  \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
844  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
845  in a calling program via the \fBpcre_fullinfo()\fP function.  in a calling program via the \fBpcre_fullinfo()\fP function.
846  .P  .P
847  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
848  single fixed starting character. A bitmap of possible starting bytes is  single fixed starting character. A bitmap of possible starting bytes is
849  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
850  matching.  matching.
851    .P
852    The two optimizations just described can be disabled by setting the
853    PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or
854    \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains
855    callouts, or make use of (*MARK), and you make use of these in cases where
856    matching fails. See the discussion of PCRE_NO_START_OPTIMIZE
857    .\" HTML <a href="#execoptions">
858    .\" </a>
859    below.
860    .\"
861  .  .
862  .  .
863  .\" HTML <a name="localesupport"></a>  .\" HTML <a name="localesupport"></a>
# Line 827  matching. Line 867  matching.
867  PCRE handles caseless matching, and determines whether characters are letters,  PCRE handles caseless matching, and determines whether characters are letters,
868  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
869  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
870  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
871  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
872  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
873  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
874  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
875    handling characters with codes greater than 128, you should either use UTF-8
876    and Unicode, or use locales, but not try to mix the two.
877  .P  .P
878  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
879  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 1054  entry; both of these return an \fBint\fP
1054  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
1055  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
1056  are the number of the capturing parenthesis, most significant byte first. The  are the number of the capturing parenthesis, most significant byte first. The
1057  rest of the entry is the corresponding name, zero terminated.  rest of the entry is the corresponding name, zero terminated.
1058  .P  .P
1059  The names are in alphabetical order. Duplicate names may appear if (?| is used  The names are in alphabetical order. Duplicate names may appear if (?| is used
1060  to create multiple groups with the same number, as described in the  to create multiple groups with the same number, as described in the
# Line 1024  in the Line 1066  in the
1066  .\" HREF  .\" HREF
1067  \fBpcrepattern\fP  \fBpcrepattern\fP
1068  .\"  .\"
1069  page. Duplicate names for subpatterns with different numbers are permitted only  page. Duplicate names for subpatterns with different numbers are permitted only
1070  if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the  if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the
1071  table in the order in which they were found in the pattern. In the absence of  table in the order in which they were found in the pattern. In the absence of
1072  (?| this is the order of increasing number; when (?| is used this is not  (?| this is the order of increasing number; when (?| is used this is not
1073  necessarily the case because later subpatterns may have lower numbers.  necessarily the case because later subpatterns may have lower numbers.
1074  .P  .P
1075  As a simple example of the name/number table, consider the following pattern  As a simple example of the name/number table, consider the following pattern
# Line 1210  fields (not necessarily in this order): Line 1252  fields (not necessarily in this order):
1252    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1253    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1254    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1255      unsigned char **\fImark\fP;
1256  .sp  .sp
1257  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
1258  are set. The flag bits are:  are set. The flag bits are:
# Line 1219  are set. The flag bits are: Line 1262  are set. The flag bits are:
1262    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1263    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1264    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1265      PCRE_EXTRA_MARK
1266  .sp  .sp
1267  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
1268  \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 1325  called. See the
1325  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1326  .\"  .\"
1327  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1328    .P
1329    If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must
1330    be set to point to a \fBchar *\fP variable. If the pattern contains any
1331    backtracking control verbs such as (*MARK:NAME), and the execution ends up with
1332    a name to pass back, a pointer to the name string (zero terminated) is placed
1333    in the variable pointed to by the \fImark\fP field. The names are within the
1334    compiled pattern; if you wish to retain such a name you must copy it before
1335    freeing the memory of a compiled pattern. If there is no name to pass back, the
1336    variable pointed to by the \fImark\fP field set to NULL. For details of the
1337    backtracking control verbs, see the section entitled
1338    .\" HTML <a href="pcrepattern#backtrackcontrol">
1339    .\" </a>
1340    "Backtracking control"
1341    .\"
1342    in the
1343    .\" HREF
1344    \fBpcrepattern\fP
1345    .\"
1346    documentation.
1347    .
1348  .  .
1349  .\" HTML <a name="execoptions"></a>  .\" HTML <a name="execoptions"></a>
1350  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
# Line 1371  valid, so PCRE searches further into the Line 1435  valid, so PCRE searches further into the
1435  .sp  .sp
1436    PCRE_NOTEMPTY_ATSTART    PCRE_NOTEMPTY_ATSTART
1437  .sp  .sp
1438  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
1439  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
1440  can occur only if the pattern contains \eK.  can occur only if the pattern contains \eK.
1441  .P  .P
# Line 1386  the Line 1450  the
1450  .\" HREF  .\" HREF
1451  \fBpcredemo\fP  \fBpcredemo\fP
1452  .\"  .\"
1453  sample program.  sample program. In the most general case, you have to check to see if the
1454    newline convention recognizes CRLF as a newline, and if so, and the current
1455    character is CR followed by LF, advance the starting offset by two characters
1456    instead of one.
1457  .sp  .sp
1458    PCRE_NO_START_OPTIMIZE    PCRE_NO_START_OPTIMIZE
1459  .sp  .sp
1460  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
1461  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
1462  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
1463  character, and fails immediately if it cannot find it, without actually running  for that character, and fails immediately if it cannot find it, without
1464  the main matching function. When callouts are in use, these optimizations can  actually running the main matching function. This means that a special item
1465  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
1466  causing performance to suffer, but ensuring that the callouts do occur.  suitable starting point for the match has been found. When callouts or (*MARK)
1467    items are in use, these "start-up" optimizations can cause them to be skipped
1468    if the pattern is never actually used. The start-up optimizations are in effect
1469    a pre-scan of the subject that takes place before the pattern is run.
1470    .P
1471    The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1472    causing performance to suffer, but ensuring that in cases where the result is
1473    "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
1474    are considered at every possible starting position in the subject string.
1475    Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
1476    Consider the pattern
1477    .sp
1478      (*COMMIT)ABC
1479    .sp
1480    When this is compiled, PCRE records the fact that a match must start with the
1481    character "A". Suppose the subject string is "DEFABC". The start-up
1482    optimization scans along the subject, finds "A" and runs the first match
1483    attempt from there. The (*COMMIT) item means that the pattern must match the
1484    current starting position, which in this case, it does. However, if the same
1485    match is run with PCRE_NO_START_OPTIMIZE set, the initial scan along the
1486    subject string does not happen. The first match attempt is run starting from
1487    "D" and when this fails, (*COMMIT) prevents any further matches being tried, so
1488    the overall result is "no match". If the pattern is studied, more start-up
1489    optimizations may be used. For example, a minimum length for the subject may be
1490    recorded. Consider the pattern
1491    .sp
1492      (*MARK:A)(X|Y)
1493    .sp
1494    The minimum length for a match is one character. If the subject is "ABC", there
1495    will be attempts to match "ABC", "BC", "C", and then finally an empty string.
1496    If the pattern is studied, the final attempt does not take place, because PCRE
1497    knows that the subject is too short, and so the (*MARK) is never encountered.
1498    In this case, studying the pattern does not affect the overall match result,
1499    which is still "no match", but it does affect the auxiliary information that is
1500    returned.
1501  .sp  .sp
1502    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1503  .sp  .sp
# Line 1427  PCRE_NO_UTF8_CHECK is set, the effect of Line 1528  PCRE_NO_UTF8_CHECK is set, the effect of
1528  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
1529  UTF-8 character, is undefined. Your program may crash.  UTF-8 character, is undefined. Your program may crash.
1530  .sp  .sp
1531    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
1532    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
1533  .sp  .sp
1534  These options turn on the partial matching feature. For backwards  These options turn on the partial matching feature. For backwards
1535  compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match  compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match
1536  occurs if the end of the subject string is reached successfully, but there are  occurs if the end of the subject string is reached successfully, but there are
1537  not enough subject characters to complete the match. If this happens when  not enough subject characters to complete the match. If this happens when
1538  PCRE_PARTIAL_HARD is set, \fBpcre_exec()\fP immediately returns  PCRE_PARTIAL_SOFT (but not PCRE_PARTIAL_HARD) is set, matching continues by
1539  PCRE_ERROR_PARTIAL. Otherwise, if PCRE_PARTIAL_SOFT is set, matching continues  testing any remaining alternatives. Only if no complete match can be found is
1540  by testing any other alternatives. Only if they all fail is PCRE_ERROR_PARTIAL  PCRE_ERROR_PARTIAL returned instead of PCRE_ERROR_NOMATCH. In other words,
1541  returned (instead of PCRE_ERROR_NOMATCH). The portion of the string that  PCRE_PARTIAL_SOFT says that the caller is prepared to handle a partial match,
1542  was inspected when the partial match was found is set as the first matching  but only if no complete match can be found.
1543  string. There is a more detailed discussion in the  .P
1544    If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a
1545    partial match is found, \fBpcre_exec()\fP immediately returns
1546    PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,
1547    when PCRE_PARTIAL_HARD is set, a partial match is considered to be more
1548    important that an alternative complete match.
1549    .P
1550    In both cases, the portion of the string that was inspected when the partial
1551    match was found is set as the first matching string. There is a more detailed
1552    discussion of partial and multi-segment matching, with examples, in the
1553  .\" HREF  .\" HREF
1554  \fBpcrepartial\fP  \fBpcrepartial\fP
1555  .\"  .\"
# Line 1591  If a pattern contains back references, b Line 1701  If a pattern contains back references, b
1701  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
1702  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
1703  automatically freed at the end of matching.  automatically freed at the end of matching.
1704    .P
1705    This error is also given if \fBpcre_stack_malloc()\fP fails in
1706    \fBpcre_exec()\fP. This can happen only when PCRE has been compiled with
1707    \fB--disable-stack-for-recursion\fP.
1708  .sp  .sp
1709    PCRE_ERROR_NOSUBSTRING    (-7)    PCRE_ERROR_NOSUBSTRING    (-7)
1710  .sp  .sp
# Line 1634  documentation for details of partial mat Line 1748  documentation for details of partial mat
1748  .sp  .sp
1749  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
1750  option was used with a compiled pattern containing items that were not  option was used with a compiled pattern containing items that were not
1751  supported for partial matching. From release 8.00 onwards, there are no  supported for partial matching. From release 8.00 onwards, there are no
1752  restrictions on partial matching.  restrictions on partial matching.
1753  .sp  .sp
1754    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
# Line 1898  a compiled pattern, using a matching alg Line 2012  a compiled pattern, using a matching alg
2012  just once, and does not backtrack. This has different characteristics to the  just once, and does not backtrack. This has different characteristics to the
2013  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
2014  patterns are not supported. Nevertheless, there are times when this kind of  patterns are not supported. Nevertheless, there are times when this kind of
2015  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
2016  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
2017  .\" HREF  .\" HREF
2018  \fBpcrematching\fP  \fBpcrematching\fP
# Line 1939  Here is an example of a simple call to \ Line 2053  Here is an example of a simple call to \
2053  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
2054  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,
2055  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
2056  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,
2057  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.
2058  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,
2059    so their description is not repeated here.
2060  .sp  .sp
2061    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
2062    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
2063  .sp  .sp
2064  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
2065  details are slightly different. When PCRE_PARTIAL_HARD is set for  details are slightly different. When PCRE_PARTIAL_HARD is set for
# Line 1956  is converted into PCRE_ERROR_PARTIAL if Line 2071  is converted into PCRE_ERROR_PARTIAL if
2071  there have been no complete matches, but there is still at least one matching  there have been no complete matches, but there is still at least one matching
2072  possibility. The portion of the string that was inspected when the longest  possibility. The portion of the string that was inspected when the longest
2073  partial match was found is set as the first matching string in both cases.  partial match was found is set as the first matching string in both cases.
2074    There is a more detailed discussion of partial and multi-segment matching, with
2075    examples, in the
2076    .\" HREF
2077    \fBpcrepartial\fP
2078    .\"
2079    documentation.
2080  .sp  .sp
2081    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
2082  .sp  .sp
# Line 2075  Cambridge CB2 3QH, England. Line 2196  Cambridge CB2 3QH, England.
2196  .rs  .rs
2197  .sp  .sp
2198  .nf  .nf
2199  Last updated: 03 October 2009  Last updated: 01 November 2010
2200  Copyright (c) 1997-2009 University of Cambridge.  Copyright (c) 1997-2010 University of Cambridge.
2201  .fi  .fi

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