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revision 579 by ph10, Wed Nov 24 17:39:25 2010 UTC revision 776 by ph10, Thu Dec 1 11:02:56 2011 UTC
# Line 1  Line 1 
1  .TH PCREAPI 3  .TH PCREAPI 3
2  .SH NAME  .SH NAME
3  PCRE - Perl-compatible regular expressions  PCRE - Perl-compatible regular expressions
4  .SH "PCRE NATIVE API"  .SH "PCRE NATIVE API BASIC FUNCTIONS"
5  .rs  .rs
6  .sp  .sp
7  .B #include <pcre.h>  .B #include <pcre.h>
# Line 25  PCRE - Perl-compatible regular expressio Line 25  PCRE - Perl-compatible regular expressio
25  .ti +5n  .ti +5n
26  .B const char **\fIerrptr\fP);  .B const char **\fIerrptr\fP);
27  .PP  .PP
28    .B void pcre_free_study(pcre_extra *\fIextra\fP);
29    .PP
30  .B int pcre_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"  .B int pcre_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
31  .ti +5n  .ti +5n
32  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
33  .ti +5n  .ti +5n
34  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);
35    .
36    .
37    .SH "PCRE NATIVE API AUXILIARY FUNCTIONS"
38    .rs
39    .sp
40    .B pcre_jit_stack *pcre_jit_stack_alloc(int \fIstartsize\fP, int \fImaxsize\fP);
41    .PP
42    .B void pcre_jit_stack_free(pcre_jit_stack *\fIstack\fP);
43    .PP
44    .B void pcre_assign_jit_stack(pcre_extra *\fIextra\fP,
45    .ti +5n
46    .B pcre_jit_callback \fIcallback\fP, void *\fIdata\fP);
47  .PP  .PP
48  .B int pcre_dfa_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"  .B int pcre_dfa_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
49  .ti +5n  .ti +5n
# Line 97  PCRE - Perl-compatible regular expressio Line 111  PCRE - Perl-compatible regular expressio
111  .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);  .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);
112  .PP  .PP
113  .B char *pcre_version(void);  .B char *pcre_version(void);
114  .PP  .
115    .
116    .SH "PCRE NATIVE API INDIRECTED FUNCTIONS"
117    .rs
118    .sp
119  .B void *(*pcre_malloc)(size_t);  .B void *(*pcre_malloc)(size_t);
120  .PP  .PP
121  .B void (*pcre_free)(void *);  .B void (*pcre_free)(void *);
# Line 114  PCRE - Perl-compatible regular expressio Line 132  PCRE - Perl-compatible regular expressio
132  .sp  .sp
133  PCRE has its own native API, which is described in this document. There are  PCRE has its own native API, which is described in this document. There are
134  also some wrapper functions that correspond to the POSIX regular expression  also some wrapper functions that correspond to the POSIX regular expression
135  API. These are described in the  API, but they do not give access to all the functionality. They are described
136    in the
137  .\" HREF  .\" HREF
138  \fBpcreposix\fP  \fBpcreposix\fP
139  .\"  .\"
140  documentation. Both of these APIs define a set of C function calls. A C++  documentation. Both of these APIs define a set of C function calls. A C++
141  wrapper is distributed with PCRE. It is documented in the  wrapper is also distributed with PCRE. It is documented in the
142  .\" HREF  .\" HREF
143  \fBpcrecpp\fP  \fBpcrecpp\fP
144  .\"  .\"
# Line 152  documentation, and the Line 171  documentation, and the
171  .\"  .\"
172  documentation describes how to compile and run it.  documentation describes how to compile and run it.
173  .P  .P
174    Just-in-time compiler support is an optional feature of PCRE that can be built
175    in appropriate hardware environments. It greatly speeds up the matching
176    performance of many patterns. Simple programs can easily request that it be
177    used if available, by setting an option that is ignored when it is not
178    relevant. More complicated programs might need to make use of the functions
179    \fBpcre_jit_stack_alloc()\fP, \fBpcre_jit_stack_free()\fP, and
180    \fBpcre_assign_jit_stack()\fP in order to control the JIT code's memory usage.
181    These functions are discussed in the
182    .\" HREF
183    \fBpcrejit\fP
184    .\"
185    documentation.
186    .P
187  A second matching function, \fBpcre_dfa_exec()\fP, which is not  A second matching function, \fBpcre_dfa_exec()\fP, which is not
188  Perl-compatible, is also provided. This uses a different algorithm for the  Perl-compatible, is also provided. This uses a different algorithm for the
189  matching. The alternative algorithm finds all possible matches (at a given  matching. The alternative algorithm finds all possible matches (at a given
# Line 282  callout function pointed to by \fBpcre_c Line 314  callout function pointed to by \fBpcre_c
314  .P  .P
315  The compiled form of a regular expression is not altered during matching, so  The compiled form of a regular expression is not altered during matching, so
316  the same compiled pattern can safely be used by several threads at once.  the same compiled pattern can safely be used by several threads at once.
317    .P
318    If the just-in-time optimization feature is being used, it needs separate
319    memory stack areas for each thread. See the
320    .\" HREF
321    \fBpcrejit\fP
322    .\"
323    documentation for more details.
324  .  .
325  .  .
326  .SH "SAVING PRECOMPILED PATTERNS FOR LATER USE"  .SH "SAVING PRECOMPILED PATTERNS FOR LATER USE"
# Line 324  otherwise it is set to zero. Line 363  otherwise it is set to zero.
363  The output is an integer that is set to one if support for Unicode character  The output is an integer that is set to one if support for Unicode character
364  properties is available; otherwise it is set to zero.  properties is available; otherwise it is set to zero.
365  .sp  .sp
366      PCRE_CONFIG_JIT
367    .sp
368    The output is an integer that is set to one if support for just-in-time
369    compiling is available; otherwise it is set to zero.
370    .sp
371    PCRE_CONFIG_NEWLINE    PCRE_CONFIG_NEWLINE
372  .sp  .sp
373  The output is an integer whose value specifies the default character sequence  The output is an integer whose value specifies the default character sequence
# Line 436  If \fIerrptr\fP is NULL, \fBpcre_compile Line 480  If \fIerrptr\fP is NULL, \fBpcre_compile
480  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
481  NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual  NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual
482  error message. This is a static string that is part of the library. You must  error message. This is a static string that is part of the library. You must
483  not try to free it. The offset from the start of the pattern to the byte that  not try to free it. Normally, the offset from the start of the pattern to the
484  was being processed when the error was discovered is placed in the variable  byte that was being processed when the error was discovered is placed in the
485  pointed to by \fIerroffset\fP, which must not be NULL. If it is, an immediate  variable pointed to by \fIerroffset\fP, which must not be NULL (if it is, an
486  error is given. Some errors are not detected until checks are carried out when  immediate error is given). However, for an invalid UTF-8 string, the offset is
487  the whole pattern has been scanned; in this case the offset is set to the end  that of the first byte of the failing character. Also, some errors are not
488  of the pattern.  detected until checks are carried out when the whole pattern has been scanned;
489    in these cases the offset passed back is the length of the pattern.
490  .P  .P
491  Note that the offset is in bytes, not characters, even in UTF-8 mode. It may  Note that the offset is in bytes, not characters, even in UTF-8 mode. It may
492  point into the middle of a UTF-8 character (for example, when  sometimes point into the middle of a UTF-8 character.
 PCRE_ERROR_BADUTF8 is returned for an invalid UTF-8 string).  
493  .P  .P
494  If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the  If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the
495  \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is  \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is
# Line 552  unescaped # outside a character class an Line 596  unescaped # outside a character class an
596  ignored. This is equivalent to Perl's /x option, and it can be changed within a  ignored. This is equivalent to Perl's /x option, and it can be changed within a
597  pattern by a (?x) option setting.  pattern by a (?x) option setting.
598  .P  .P
599  Which characters are interpreted as newlines  Which characters are interpreted as newlines is controlled by the options
600  is controlled by the options passed to \fBpcre_compile()\fP or by a special  passed to \fBpcre_compile()\fP or by a special sequence at the start of the
601  sequence at the start of the pattern, as described in the section entitled  pattern, as described in the section entitled
602  .\" HTML <a href="pcrepattern.html#newlines">  .\" HTML <a href="pcrepattern.html#newlines">
603  .\" </a>  .\" </a>
604  "Newline conventions"  "Newline conventions"
# Line 599  character). Thus, the pattern AB]CD beco Line 643  character). Thus, the pattern AB]CD beco
643  string (by default this causes the current matching alternative to fail). A  string (by default this causes the current matching alternative to fail). A
644  pattern such as (\e1)(a) succeeds when this option is set (assuming it can find  pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
645  an "a" in the subject), whereas it fails by default, for Perl compatibility.  an "a" in the subject), whereas it fails by default, for Perl compatibility.
646    .P
647    (3) \eU matches an upper case "U" character; by default \eU causes a compile
648    time error (Perl uses \eU to upper case subsequent characters).
649    .P
650    (4) \eu matches a lower case "u" character unless it is followed by four
651    hexadecimal digits, in which case the hexadecimal number defines the code point
652    to match. By default, \eu causes a compile time error (Perl uses it to upper
653    case the following character).
654    .P
655    (5) \ex matches a lower case "x" character unless it is followed by two
656    hexadecimal digits, in which case the hexadecimal number defines the code point
657    to match. By default, as in Perl, a hexadecimal number is always expected after
658    \ex, but it may have zero, one, or two digits (so, for example, \exz matches a
659    binary zero character followed by z).
660  .sp  .sp
661    PCRE_MULTILINE    PCRE_MULTILINE
662  .sp  .sp
# Line 701  of UTF-8 characters instead of single-by Line 759  of UTF-8 characters instead of single-by
759  available only when PCRE is built to include UTF-8 support. If not, the use  available only when PCRE is built to include UTF-8 support. If not, the use
760  of this option provokes an error. Details of how this option changes the  of this option provokes an error. Details of how this option changes the
761  behaviour of PCRE are given in the  behaviour of PCRE are given in the
 .\" HTML <a href="pcre.html#utf8support">  
 .\" </a>  
 section on UTF-8 support  
 .\"  
 in the main  
762  .\" HREF  .\" HREF
763  \fBpcre\fP  \fBpcreunicode\fP
764  .\"  .\"
765  page.  page.
766  .sp  .sp
# Line 777  out of use. To avoid confusion, they hav Line 830  out of use. To avoid confusion, they hav
830    34  character value in \ex{...} sequence is too large    34  character value in \ex{...} sequence is too large
831    35  invalid condition (?(0)    35  invalid condition (?(0)
832    36  \eC not allowed in lookbehind assertion    36  \eC not allowed in lookbehind assertion
833    37  PCRE does not support \eL, \el, \eN, \eU, or \eu    37  PCRE does not support \eL, \el, \eN{name}, \eU, or \eu
834    38  number after (?C is > 255    38  number after (?C is > 255
835    39  closing ) for (?C expected    39  closing ) for (?C expected
836    40  recursive call could loop indefinitely    40  recursive call could loop indefinitely
# Line 811  out of use. To avoid confusion, they hav Line 864  out of use. To avoid confusion, they hav
864          not allowed          not allowed
865    66  (*MARK) must have an argument    66  (*MARK) must have an argument
866    67  this version of PCRE is not compiled with PCRE_UCP support    67  this version of PCRE is not compiled with PCRE_UCP support
867      68  \ec must be followed by an ASCII character
868      69  \ek is not followed by a braced, angle-bracketed, or quoted name
869  .sp  .sp
870  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
871  be used if the limits were changed when PCRE was built.  be used if the limits were changed when PCRE was built.
872  .  .
873  .  .
874    .\" HTML <a name="studyingapattern"></a>
875  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
876  .rs  .rs
877  .sp  .sp
# Line 846  If studying the pattern does not produce Line 902  If studying the pattern does not produce
902  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
903  \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.
904  .P  .P
905  The second argument of \fBpcre_study()\fP contains option bits. At present, no  The second argument of \fBpcre_study()\fP contains option bits. There is only
906  options are defined, and this argument should always be zero.  one option: PCRE_STUDY_JIT_COMPILE. If this is set, and the just-in-time
907    compiler is available, the pattern is further compiled into machine code that
908    executes much faster than the \fBpcre_exec()\fP matching function. If
909    the just-in-time compiler is not available, this option is ignored. All other
910    bits in the \fIoptions\fP argument must be zero.
911    .P
912    JIT compilation is a heavyweight optimization. It can take some time for
913    patterns to be analyzed, and for one-off matches and simple patterns the
914    benefit of faster execution might be offset by a much slower study time.
915    Not all patterns can be optimized by the JIT compiler. For those that cannot be
916    handled, matching automatically falls back to the \fBpcre_exec()\fP
917    interpreter. For more details, see the
918    .\" HREF
919    \fBpcrejit\fP
920    .\"
921    documentation.
922  .P  .P
923  The third argument for \fBpcre_study()\fP is a pointer for an error message. If  The third argument for \fBpcre_study()\fP is a pointer for an error message. If
924  studying succeeds (even if no data is returned), the variable it points to is  studying succeeds (even if no data is returned), the variable it points to is
# Line 856  static string that is part of the librar Line 927  static string that is part of the librar
927  should test the error pointer for NULL after calling \fBpcre_study()\fP, to be  should test the error pointer for NULL after calling \fBpcre_study()\fP, to be
928  sure that it has run successfully.  sure that it has run successfully.
929  .P  .P
930  This is a typical call to \fBpcre_study\fP():  When you are finished with a pattern, you can free the memory used for the
931    study data by calling \fBpcre_free_study()\fP. This function was added to the
932    API for release 8.20. For earlier versions, the memory could be freed with
933    \fBpcre_free()\fP, just like the pattern itself. This will still work in cases
934    where PCRE_STUDY_JIT_COMPILE is not used, but it is advisable to change to the
935    new function when convenient.
936    .P
937    This is a typical way in which \fBpcre_study\fP() is used (except that in a
938    real application there should be tests for errors):
939  .sp  .sp
940    pcre_extra *pe;    int rc;
941    pe = pcre_study(    pcre *re;
942      pcre_extra *sd;
943      re = pcre_compile("pattern", 0, &error, &erroroffset, NULL);
944      sd = pcre_study(
945      re,             /* result of pcre_compile() */      re,             /* result of pcre_compile() */
946      0,              /* no options exist */      0,              /* no options */
947      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
948      rc = pcre_exec(   /* see below for details of pcre_exec() options */
949        re, sd, "subject", 7, 0, 0, ovector, 30);
950      ...
951      pcre_free_study(sd);
952      pcre_free(re);
953  .sp  .sp
954  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
955  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
# Line 877  single fixed starting character. A bitma Line 964  single fixed starting character. A bitma
964  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
965  matching.  matching.
966  .P  .P
967  The two optimizations just described can be disabled by setting the  These two optimizations apply to both \fBpcre_exec()\fP and
968  PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or  \fBpcre_dfa_exec()\fP. However, they are not used by \fBpcre_exec()\fP if
969    \fBpcre_study()\fP is called with the PCRE_STUDY_JIT_COMPILE option, and
970    just-in-time compiling is successful. The optimizations can be disabled by
971    setting the PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or
972  \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains  \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains
973  callouts or (*MARK), and you want to make use of these facilities in cases  callouts or (*MARK) (which cannot be handled by the JIT compiler), and you want
974  where matching fails. See the discussion of PCRE_NO_START_OPTIMIZE  to make use of these facilities in cases where matching fails. See the
975    discussion of PCRE_NO_START_OPTIMIZE
976  .\" HTML <a href="#execoptions">  .\" HTML <a href="#execoptions">
977  .\" </a>  .\" </a>
978  below.  below.
# Line 946  one in which it was compiled. Passing ta Line 1037  one in which it was compiled. Passing ta
1037  below in the section on matching a pattern.  below in the section on matching a pattern.
1038  .  .
1039  .  .
1040    .\" HTML <a name="infoaboutpattern"></a>
1041  .SH "INFORMATION ABOUT A PATTERN"  .SH "INFORMATION ABOUT A PATTERN"
1042  .rs  .rs
1043  .sp  .sp
# Line 977  check against passing an arbitrary memor Line 1069  check against passing an arbitrary memor
1069    size_t length;    size_t length;
1070    rc = pcre_fullinfo(    rc = pcre_fullinfo(
1071      re,               /* result of pcre_compile() */      re,               /* result of pcre_compile() */
1072      pe,               /* result of pcre_study(), or NULL */      sd,               /* result of pcre_study(), or NULL */
1073      PCRE_INFO_SIZE,   /* what is required */      PCRE_INFO_SIZE,   /* what is required */
1074      &length);         /* where to put the data */      &length);         /* where to put the data */
1075  .sp  .sp
# Line 1042  Return 1 if the (?J) or (?-J) option set Line 1134  Return 1 if the (?J) or (?-J) option set
1134  0. The fourth argument should point to an \fBint\fP variable. (?J) and  0. The fourth argument should point to an \fBint\fP variable. (?J) and
1135  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
1136  .sp  .sp
1137      PCRE_INFO_JIT
1138    .sp
1139    Return 1 if the pattern was studied with the PCRE_STUDY_JIT_COMPILE option, and
1140    just-in-time compiling was successful. The fourth argument should point to an
1141    \fBint\fP variable. A return value of 0 means that JIT support is not available
1142    in this version of PCRE, or that the pattern was not studied with the
1143    PCRE_STUDY_JIT_COMPILE option, or that the JIT compiler could not handle this
1144    particular pattern. See the
1145    .\" HREF
1146    \fBpcrejit\fP
1147    .\"
1148    documentation for details of what can and cannot be handled.
1149    .sp
1150    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
1151  .sp  .sp
1152  Return the value of the rightmost literal byte that must exist in any matched  Return the value of the rightmost literal byte that must exist in any matched
# Line 1157  For such patterns, the PCRE_ANCHORED bit Line 1262  For such patterns, the PCRE_ANCHORED bit
1262  .sp  .sp
1263    PCRE_INFO_SIZE    PCRE_INFO_SIZE
1264  .sp  .sp
1265  Return the size of the compiled pattern, that is, the value that was passed as  Return the size of the compiled pattern. The fourth argument should point to a
1266  the argument to \fBpcre_malloc()\fP when PCRE was getting memory in which to  \fBsize_t\fP variable. This value does not include the size of the \fBpcre\fP
1267  place the compiled data. The fourth argument should point to a \fBsize_t\fP  structure that is returned by \fBpcre_compile()\fP. The value that is passed as
1268  variable.  the argument to \fBpcre_malloc()\fP when \fBpcre_compile()\fP is getting memory
1269    in which to place the compiled data is the value returned by this option plus
1270    the size of the \fBpcre\fP structure. Studying a compiled pattern, with or
1271    without JIT, does not alter the value returned by this option.
1272  .sp  .sp
1273    PCRE_INFO_STUDYSIZE    PCRE_INFO_STUDYSIZE
1274  .sp  .sp
1275  Return the size of the data block pointed to by the \fIstudy_data\fP field in  Return the size of the data block pointed to by the \fIstudy_data\fP field in a
1276  a \fBpcre_extra\fP block. That is, it is the value that was passed to  \fBpcre_extra\fP block. If \fBpcre_extra\fP is NULL, or there is no study data,
1277  \fBpcre_malloc()\fP when PCRE was getting memory into which to place the data  zero is returned. The fourth argument should point to a \fBsize_t\fP variable.
1278  created by \fBpcre_study()\fP. If \fBpcre_extra\fP is NULL, or there is no  The \fIstudy_data\fP field is set by \fBpcre_study()\fP to record information
1279  study data, zero is returned. The fourth argument should point to a  that will speed up matching (see the section entitled
1280  \fBsize_t\fP variable.  .\" HTML <a href="#studyingapattern">
1281    .\" </a>
1282    "Studying a pattern"
1283    .\"
1284    above). The format of the \fIstudy_data\fP block is private, but its length
1285    is made available via this option so that it can be saved and restored (see the
1286    .\" HREF
1287    \fBpcreprecompile\fP
1288    .\"
1289    documentation for details).
1290  .  .
1291  .  .
1292  .SH "OBSOLETE INFO FUNCTION"  .SH "OBSOLETE INFO FUNCTION"
# Line 1231  is different. (This seems a highly unlik Line 1348  is different. (This seems a highly unlik
1348  The function \fBpcre_exec()\fP is called to match a subject string against a  The function \fBpcre_exec()\fP is called to match a subject string against a
1349  compiled pattern, which is passed in the \fIcode\fP argument. If the  compiled pattern, which is passed in the \fIcode\fP argument. If the
1350  pattern was studied, the result of the study should be passed in the  pattern was studied, the result of the study should be passed in the
1351  \fIextra\fP argument. This function is the main matching facility of the  \fIextra\fP argument. You can call \fBpcre_exec()\fP with the same \fIcode\fP
1352  library, and it operates in a Perl-like manner. For specialist use there is  and \fIextra\fP arguments as many times as you like, in order to match
1353  also an alternative matching function, which is described  different subject strings with the same pattern.
1354    .P
1355    This function is the main matching facility of the library, and it operates in
1356    a Perl-like manner. For specialist use there is also an alternative matching
1357    function, which is described
1358  .\" HTML <a href="#dfamatch">  .\" HTML <a href="#dfamatch">
1359  .\" </a>  .\" </a>
1360  below  below
# Line 1264  Here is an example of a simple call to \ Line 1385  Here is an example of a simple call to \
1385      ovector,        /* vector of integers for substring information */      ovector,        /* vector of integers for substring information */
1386      30);            /* number of elements (NOT size in bytes) */      30);            /* number of elements (NOT size in bytes) */
1387  .  .
1388    .
1389  .\" HTML <a name="extradata"></a>  .\" HTML <a name="extradata"></a>
1390  .SS "Extra data for \fBpcre_exec()\fR"  .SS "Extra data for \fBpcre_exec()\fR"
1391  .rs  .rs
# Line 1276  fields (not necessarily in this order): Line 1398  fields (not necessarily in this order):
1398  .sp  .sp
1399    unsigned long int \fIflags\fP;    unsigned long int \fIflags\fP;
1400    void *\fIstudy_data\fP;    void *\fIstudy_data\fP;
1401      void *\fIexecutable_jit\fP;
1402    unsigned long int \fImatch_limit\fP;    unsigned long int \fImatch_limit\fP;
1403    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1404    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
# Line 1286  The \fIflags\fP field is a bitmap that s Line 1409  The \fIflags\fP field is a bitmap that s
1409  are set. The flag bits are:  are set. The flag bits are:
1410  .sp  .sp
1411    PCRE_EXTRA_STUDY_DATA    PCRE_EXTRA_STUDY_DATA
1412      PCRE_EXTRA_EXECUTABLE_JIT
1413    PCRE_EXTRA_MATCH_LIMIT    PCRE_EXTRA_MATCH_LIMIT
1414    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1415    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1416    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1417    PCRE_EXTRA_MARK    PCRE_EXTRA_MARK
1418  .sp  .sp
1419  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 and sometimes
1420  \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with  the \fIexecutable_jit\fP field are set in the \fBpcre_extra\fP block that is
1421  the appropriate flag bit. You should not set this yourself, but you may add to  returned by \fBpcre_study()\fP, together with the appropriate flag bits. You
1422  the block by setting the other fields and their corresponding flag bits.  should not set these yourself, but you may add to the block by setting the
1423    other fields and their corresponding flag bits.
1424  .P  .P
1425  The \fImatch_limit\fP field provides a means of preventing PCRE from using up a  The \fImatch_limit\fP field provides a means of preventing PCRE from using up a
1426  vast amount of resources when running patterns that are not going to match,  vast amount of resources when running patterns that are not going to match,
1427  but which have a very large number of possibilities in their search trees. The  but which have a very large number of possibilities in their search trees. The
1428  classic example is a pattern that uses nested unlimited repeats.  classic example is a pattern that uses nested unlimited repeats.
1429  .P  .P
1430  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly  Internally, \fBpcre_exec()\fP uses a function called \fBmatch()\fP, which it
1431  (sometimes recursively). The limit set by \fImatch_limit\fP is imposed on the  calls repeatedly (sometimes recursively). The limit set by \fImatch_limit\fP is
1432  number of times this function is called during a match, which has the effect of  imposed on the number of times this function is called during a match, which
1433  limiting the amount of backtracking that can take place. For patterns that are  has the effect of limiting the amount of backtracking that can take place. For
1434  not anchored, the count restarts from zero for each position in the subject  patterns that are not anchored, the count restarts from zero for each position
1435  string.  in the subject string.
1436    .P
1437    When \fBpcre_exec()\fP is called with a pattern that was successfully studied
1438    with the PCRE_STUDY_JIT_COMPILE option, the way that the matching is executed
1439    is entirely different. However, there is still the possibility of runaway
1440    matching that goes on for a very long time, and so the \fImatch_limit\fP value
1441    is also used in this case (but in a different way) to limit how long the
1442    matching can continue.
1443  .P  .P
1444  The default value for the limit can be set when PCRE is built; the default  The default value for the limit can be set when PCRE is built; the default
1445  default is 10 million, which handles all but the most extreme cases. You can  default is 10 million, which handles all but the most extreme cases. You can
# Line 1322  limits the depth of recursion. The recur Line 1454  limits the depth of recursion. The recur
1454  total number of calls, because not all calls to \fBmatch()\fP are recursive.  total number of calls, because not all calls to \fBmatch()\fP are recursive.
1455  This limit is of use only if it is set smaller than \fImatch_limit\fP.  This limit is of use only if it is set smaller than \fImatch_limit\fP.
1456  .P  .P
1457  Limiting the recursion depth limits the amount of stack that can be used, or,  Limiting the recursion depth limits the amount of machine stack that can be
1458  when PCRE has been compiled to use memory on the heap instead of the stack, the  used, or, when PCRE has been compiled to use memory on the heap instead of the
1459  amount of heap memory that can be used.  stack, the amount of heap memory that can be used. This limit is not relevant,
1460    and is ignored, if the pattern was successfully studied with
1461    PCRE_STUDY_JIT_COMPILE.
1462  .P  .P
1463  The default value for \fImatch_limit_recursion\fP can be set when PCRE is  The default value for \fImatch_limit_recursion\fP can be set when PCRE is
1464  built; the default default is the same value as the default for  built; the default default is the same value as the default for
# Line 1383  zero. The only bits that may be set are Line 1517  zero. The only bits that may be set are
1517  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1518  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
1519  PCRE_PARTIAL_HARD.  PCRE_PARTIAL_HARD.
1520    .P
1521    If the pattern was successfully studied with the PCRE_STUDY_JIT_COMPILE option,
1522    the only supported options for JIT execution are PCRE_NO_UTF8_CHECK,
1523    PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NOTEMPTY_ATSTART. Note in
1524    particular that partial matching is not supported. If an unsupported option is
1525    used, JIT execution is disabled and the normal interpretive code in
1526    \fBpcre_exec()\fP is run.
1527  .sp  .sp
1528    PCRE_ANCHORED    PCRE_ANCHORED
1529  .sp  .sp
# Line 1547  in the main Line 1688  in the main
1688  .\"  .\"
1689  page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns  page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1690  the error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is  the error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is
1691  a truncated UTF-8 character at the end of the subject, PCRE_ERROR_SHORTUTF8. If  a truncated UTF-8 character at the end of the subject, PCRE_ERROR_SHORTUTF8. In
1692  \fIstartoffset\fP contains a value that does not point to the start of a UTF-8  both cases, information about the precise nature of the error may also be
1693  character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is  returned (see the descriptions of these errors in the section entitled \fIError
1694    return values from\fP \fBpcre_exec()\fP
1695    .\" HTML <a href="#errorlist">
1696    .\" </a>
1697    below).
1698    .\"
1699    If \fIstartoffset\fP contains a value that does not point to the start of a
1700    UTF-8 character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
1701  returned.  returned.
1702  .P  .P
1703  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 1682  string that it matched that is returned. Line 1830  string that it matched that is returned.
1830  .P  .P
1831  If the vector is too small to hold all the captured substring offsets, it is  If the vector is too small to hold all the captured substring offsets, it is
1832  used as far as possible (up to two-thirds of its length), and the function  used as far as possible (up to two-thirds of its length), and the function
1833  returns a value of zero. If the substring offsets are not of interest,  returns a value of zero. If neither the actual string matched not any captured
1834  \fBpcre_exec()\fP may be called with \fIovector\fP passed as NULL and  substrings are of interest, \fBpcre_exec()\fP may be called with \fIovector\fP
1835  \fIovecsize\fP as zero. However, if the pattern contains back references and  passed as NULL and \fIovecsize\fP as zero. However, if the pattern contains
1836  the \fIovector\fP is not big enough to remember the related substrings, PCRE  back references and the \fIovector\fP is not big enough to remember the related
1837  has to get additional memory for use during matching. Thus it is usually  substrings, PCRE has to get additional memory for use during matching. Thus it
1838  advisable to supply an \fIovector\fP.  is usually advisable to supply an \fIovector\fP of reasonable size.
1839    .P
1840    There are some cases where zero is returned (indicating vector overflow) when
1841    in fact the vector is exactly the right size for the final match. For example,
1842    consider the pattern
1843    .sp
1844      (a)(?:(b)c|bd)
1845    .sp
1846    If a vector of 6 elements (allowing for only 1 captured substring) is given
1847    with subject string "abd", \fBpcre_exec()\fP will try to set the second
1848    captured string, thereby recording a vector overflow, before failing to match
1849    "c" and backing up to try the second alternative. The zero return, however,
1850    does correctly indicate that the maximum number of slots (namely 2) have been
1851    filled. In similar cases where there is temporary overflow, but the final
1852    number of used slots is actually less than the maximum, a non-zero value is
1853    returned.
1854  .P  .P
1855  The \fBpcre_fullinfo()\fP function can be used to find out how many capturing  The \fBpcre_fullinfo()\fP function can be used to find out how many capturing
1856  subpatterns there are in a compiled pattern. The smallest size for  subpatterns there are in a compiled pattern. The smallest size for
# Line 1708  return from the function is 2, because t Line 1871  return from the function is 2, because t
1871  number is 1, and the offsets for for the second and third capturing subpatterns  number is 1, and the offsets for for the second and third capturing subpatterns
1872  (assuming the vector is large enough, of course) are set to -1.  (assuming the vector is large enough, of course) are set to -1.
1873  .P  .P
1874  \fBNote\fP: Elements of \fIovector\fP that do not correspond to capturing  \fBNote\fP: Elements in the first two-thirds of \fIovector\fP that do not
1875  parentheses in the pattern are never changed. That is, if a pattern contains  correspond to capturing parentheses in the pattern are never changed. That is,
1876  \fIn\fP capturing parentheses, no more than \fIovector[0]\fP to  if a pattern contains \fIn\fP capturing parentheses, no more than
1877  \fIovector[2n+1]\fP are set by \fBpcre_exec()\fP. The other elements retain  \fIovector[0]\fP to \fIovector[2n+1]\fP are set by \fBpcre_exec()\fP. The other
1878  whatever values they previously had.  elements (in the first two-thirds) retain whatever values they previously had.
1879  .P  .P
1880  Some convenience functions are provided for extracting the captured substrings  Some convenience functions are provided for extracting the captured substrings
1881  as separate strings. These are described below.  as separate strings. These are described below.
1882  .  .
1883    .
1884  .\" HTML <a name="errorlist"></a>  .\" HTML <a name="errorlist"></a>
1885  .SS "Error return values from \fBpcre_exec()\fP"  .SS "Error return values from \fBpcre_exec()\fP"
1886  .rs  .rs
# Line 1786  documentation for details. Line 1950  documentation for details.
1950  .sp  .sp
1951    PCRE_ERROR_BADUTF8        (-10)    PCRE_ERROR_BADUTF8        (-10)
1952  .sp  .sp
1953  A string that contains an invalid UTF-8 byte sequence was passed as a subject.  A string that contains an invalid UTF-8 byte sequence was passed as a subject,
1954  However, if PCRE_PARTIAL_HARD is set and the problem is a truncated UTF-8  and the PCRE_NO_UTF8_CHECK option was not set. If the size of the output vector
1955  character at the end of the subject, PCRE_ERROR_SHORTUTF8 is used instead.  (\fIovecsize\fP) is at least 2, the byte offset to the start of the the invalid
1956    UTF-8 character is placed in the first element, and a reason code is placed in
1957    the second element. The reason codes are listed in the
1958    .\" HTML <a href="#badutf8reasons">
1959    .\" </a>
1960    following section.
1961    .\"
1962    For backward compatibility, if PCRE_PARTIAL_HARD is set and the problem is a
1963    truncated UTF-8 character at the end of the subject (reason codes 1 to 5),
1964    PCRE_ERROR_SHORTUTF8 is returned instead of PCRE_ERROR_BADUTF8.
1965  .sp  .sp
1966    PCRE_ERROR_BADUTF8_OFFSET (-11)    PCRE_ERROR_BADUTF8_OFFSET (-11)
1967  .sp  .sp
1968  The UTF-8 byte sequence that was passed as a subject was valid, but the value  The UTF-8 byte sequence that was passed as a subject was checked and found to
1969  of \fIstartoffset\fP did not point to the beginning of a UTF-8 character or the  be valid (the PCRE_NO_UTF8_CHECK option was not set), but the value of
1970    \fIstartoffset\fP did not point to the beginning of a UTF-8 character or the
1971  end of the subject.  end of the subject.
1972  .sp  .sp
1973    PCRE_ERROR_PARTIAL        (-12)    PCRE_ERROR_PARTIAL        (-12)
# Line 1837  subject, that is, the value in \fIlength Line 2011  subject, that is, the value in \fIlength
2011  .sp  .sp
2012    PCRE_ERROR_SHORTUTF8      (-25)    PCRE_ERROR_SHORTUTF8      (-25)
2013  .sp  .sp
2014  The subject string ended with an incomplete (truncated) UTF-8 character, and  This error is returned instead of PCRE_ERROR_BADUTF8 when the subject string
2015  the PCRE_PARTIAL_HARD option was set. Without this option, PCRE_ERROR_BADUTF8  ends with a truncated UTF-8 character and the PCRE_PARTIAL_HARD option is set.
2016  is returned in this situation.  Information about the failure is returned as for PCRE_ERROR_BADUTF8. It is in
2017    fact sufficient to detect this case, but this special error code for
2018    PCRE_PARTIAL_HARD precedes the implementation of returned information; it is
2019    retained for backwards compatibility.
2020    .sp
2021      PCRE_ERROR_RECURSELOOP    (-26)
2022    .sp
2023    This error is returned when \fBpcre_exec()\fP detects a recursion loop within
2024    the pattern. Specifically, it means that either the whole pattern or a
2025    subpattern has been called recursively for the second time at the same position
2026    in the subject string. Some simple patterns that might do this are detected and
2027    faulted at compile time, but more complicated cases, in particular mutual
2028    recursions between two different subpatterns, cannot be detected until run
2029    time.
2030    .sp
2031      PCRE_ERROR_JIT_STACKLIMIT (-27)
2032    .sp
2033    This error is returned when a pattern that was successfully studied using the
2034    PCRE_STUDY_JIT_COMPILE option is being matched, but the memory available for
2035    the just-in-time processing stack is not large enough. See the
2036    .\" HREF
2037    \fBpcrejit\fP
2038    .\"
2039    documentation for more details.
2040  .P  .P
2041  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
2042  .  .
2043  .  .
2044    .\" HTML <a name="badutf8reasons"></a>
2045    .SS "Reason codes for invalid UTF-8 strings"
2046    .rs
2047    .sp
2048    When \fBpcre_exec()\fP returns either PCRE_ERROR_BADUTF8 or
2049    PCRE_ERROR_SHORTUTF8, and the size of the output vector (\fIovecsize\fP) is at
2050    least 2, the offset of the start of the invalid UTF-8 character is placed in
2051    the first output vector element (\fIovector[0]\fP) and a reason code is placed
2052    in the second element (\fIovector[1]\fP). The reason codes are given names in
2053    the \fBpcre.h\fP header file:
2054    .sp
2055      PCRE_UTF8_ERR1
2056      PCRE_UTF8_ERR2
2057      PCRE_UTF8_ERR3
2058      PCRE_UTF8_ERR4
2059      PCRE_UTF8_ERR5
2060    .sp
2061    The string ends with a truncated UTF-8 character; the code specifies how many
2062    bytes are missing (1 to 5). Although RFC 3629 restricts UTF-8 characters to be
2063    no longer than 4 bytes, the encoding scheme (originally defined by RFC 2279)
2064    allows for up to 6 bytes, and this is checked first; hence the possibility of
2065    4 or 5 missing bytes.
2066    .sp
2067      PCRE_UTF8_ERR6
2068      PCRE_UTF8_ERR7
2069      PCRE_UTF8_ERR8
2070      PCRE_UTF8_ERR9
2071      PCRE_UTF8_ERR10
2072    .sp
2073    The two most significant bits of the 2nd, 3rd, 4th, 5th, or 6th byte of the
2074    character do not have the binary value 0b10 (that is, either the most
2075    significant bit is 0, or the next bit is 1).
2076    .sp
2077      PCRE_UTF8_ERR11
2078      PCRE_UTF8_ERR12
2079    .sp
2080    A character that is valid by the RFC 2279 rules is either 5 or 6 bytes long;
2081    these code points are excluded by RFC 3629.
2082    .sp
2083      PCRE_UTF8_ERR13
2084    .sp
2085    A 4-byte character has a value greater than 0x10fff; these code points are
2086    excluded by RFC 3629.
2087    .sp
2088      PCRE_UTF8_ERR14
2089    .sp
2090    A 3-byte character has a value in the range 0xd800 to 0xdfff; this range of
2091    code points are reserved by RFC 3629 for use with UTF-16, and so are excluded
2092    from UTF-8.
2093    .sp
2094      PCRE_UTF8_ERR15
2095      PCRE_UTF8_ERR16
2096      PCRE_UTF8_ERR17
2097      PCRE_UTF8_ERR18
2098      PCRE_UTF8_ERR19
2099    .sp
2100    A 2-, 3-, 4-, 5-, or 6-byte character is "overlong", that is, it codes for a
2101    value that can be represented by fewer bytes, which is invalid. For example,
2102    the two bytes 0xc0, 0xae give the value 0x2e, whose correct coding uses just
2103    one byte.
2104    .sp
2105      PCRE_UTF8_ERR20
2106    .sp
2107    The two most significant bits of the first byte of a character have the binary
2108    value 0b10 (that is, the most significant bit is 1 and the second is 0). Such a
2109    byte can only validly occur as the second or subsequent byte of a multi-byte
2110    character.
2111    .sp
2112      PCRE_UTF8_ERR21
2113    .sp
2114    The first byte of a character has the value 0xfe or 0xff. These values can
2115    never occur in a valid UTF-8 string.
2116    .
2117    .
2118  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
2119  .rs  .rs
2120  .sp  .sp
# Line 2006  names are not included in the compiled c Line 2277  names are not included in the compiled c
2277  numbers. For this reason, the use of different names for subpatterns of the  numbers. For this reason, the use of different names for subpatterns of the
2278  same number causes an error at compile time.  same number causes an error at compile time.
2279  .  .
2280    .
2281  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
2282  .rs  .rs
2283  .sp  .sp
# Line 2039  fourth are pointers to variables which a Line 2311  fourth are pointers to variables which a
2311  has run, they point to the first and last entries in the name-to-number table  has run, they point to the first and last entries in the name-to-number table
2312  for the given name. The function itself returns the length of each entry, or  for the given name. The function itself returns the length of each entry, or
2313  PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is  PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is
2314  described above in the section entitled \fIInformation about a pattern\fP.  described above in the section entitled \fIInformation about a pattern\fP
2315    .\" HTML <a href="#infoaboutpattern">
2316    .\" </a>
2317    above.
2318    .\"
2319  Given all the relevant entries for the name, you can extract each of their  Given all the relevant entries for the name, you can extract each of their
2320  numbers, and hence the captured data, if any.  numbers, and hence the captured data, if any.
2321  .  .
# Line 2169  match. There is more discussion of this Line 2445  match. There is more discussion of this
2445  .\"  .\"
2446  documentation.  documentation.
2447  .  .
2448    .
2449  .SS "Successful returns from \fBpcre_dfa_exec()\fP"  .SS "Successful returns from \fBpcre_dfa_exec()\fP"
2450  .rs  .rs
2451  .sp  .sp
# Line 2200  returns data, even though the meaning of Line 2477  returns data, even though the meaning of
2477  The strings are returned in reverse order of length; that is, the longest  The strings are returned in reverse order of length; that is, the longest
2478  matching string is given first. If there were too many matches to fit into  matching string is given first. If there were too many matches to fit into
2479  \fIovector\fP, the yield of the function is zero, and the vector is filled with  \fIovector\fP, the yield of the function is zero, and the vector is filled with
2480  the longest matches.  the longest matches. Unlike \fBpcre_exec()\fP, \fBpcre_dfa_exec()\fP can use
2481    the entire \fIovector\fP for returning matched strings.
2482    .
2483  .  .
2484  .SS "Error returns from \fBpcre_dfa_exec()\fP"  .SS "Error returns from \fBpcre_dfa_exec()\fP"
2485  .rs  .rs
# Line 2229  group. These are not supported. Line 2508  group. These are not supported.
2508    PCRE_ERROR_DFA_UMLIMIT    (-18)    PCRE_ERROR_DFA_UMLIMIT    (-18)
2509  .sp  .sp
2510  This return is given if \fBpcre_dfa_exec()\fP is called with an \fIextra\fP  This return is given if \fBpcre_dfa_exec()\fP is called with an \fIextra\fP
2511  block that contains a setting of the \fImatch_limit\fP field. This is not  block that contains a setting of the \fImatch_limit\fP or
2512  supported (it is meaningless).  \fImatch_limit_recursion\fP fields. This is not supported (these fields are
2513    meaningless for DFA matching).
2514  .sp  .sp
2515    PCRE_ERROR_DFA_WSSIZE     (-19)    PCRE_ERROR_DFA_WSSIZE     (-19)
2516  .sp  .sp
# Line 2267  Cambridge CB2 3QH, England. Line 2547  Cambridge CB2 3QH, England.
2547  .rs  .rs
2548  .sp  .sp
2549  .nf  .nf
2550  Last updated: 21 November 2010  Last updated: 01 December 2011
2551  Copyright (c) 1997-2010 University of Cambridge.  Copyright (c) 1997-2011 University of Cambridge.
2552  .fi  .fi

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