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revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC revision 391 by ph10, Tue Mar 17 21:16:01 2009 UTC
# Line 7  PCRE - Perl-compatible regular expressio Line 7  PCRE - Perl-compatible regular expressio
7  .B #include <pcre.h>  .B #include <pcre.h>
8  .PP  .PP
9  .SM  .SM
 .br  
10  .B pcre *pcre_compile(const char *\fIpattern\fP, int \fIoptions\fP,  .B pcre *pcre_compile(const char *\fIpattern\fP, int \fIoptions\fP,
11  .ti +5n  .ti +5n
12  .B const char **\fIerrptr\fP, int *\fIerroffset\fP,  .B const char **\fIerrptr\fP, int *\fIerroffset\fP,
13  .ti +5n  .ti +5n
14  .B const unsigned char *\fItableptr\fP);  .B const unsigned char *\fItableptr\fP);
15  .PP  .PP
 .br  
16  .B pcre *pcre_compile2(const char *\fIpattern\fP, int \fIoptions\fP,  .B pcre *pcre_compile2(const char *\fIpattern\fP, int \fIoptions\fP,
17  .ti +5n  .ti +5n
18  .B int *\fIerrorcodeptr\fP,  .B int *\fIerrorcodeptr\fP,
# Line 23  PCRE - Perl-compatible regular expressio Line 21  PCRE - Perl-compatible regular expressio
21  .ti +5n  .ti +5n
22  .B const unsigned char *\fItableptr\fP);  .B const unsigned char *\fItableptr\fP);
23  .PP  .PP
 .br  
24  .B pcre_extra *pcre_study(const pcre *\fIcode\fP, int \fIoptions\fP,  .B pcre_extra *pcre_study(const pcre *\fIcode\fP, int \fIoptions\fP,
25  .ti +5n  .ti +5n
26  .B const char **\fIerrptr\fP);  .B const char **\fIerrptr\fP);
27  .PP  .PP
 .br  
28  .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,"
29  .ti +5n  .ti +5n
30  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
31  .ti +5n  .ti +5n
32  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);
33  .PP  .PP
 .br  
34  .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,"
35  .ti +5n  .ti +5n
36  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
# Line 44  PCRE - Perl-compatible regular expressio Line 39  PCRE - Perl-compatible regular expressio
39  .ti +5n  .ti +5n
40  .B int *\fIworkspace\fP, int \fIwscount\fP);  .B int *\fIworkspace\fP, int \fIwscount\fP);
41  .PP  .PP
 .br  
42  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,
43  .ti +5n  .ti +5n
44  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 53  PCRE - Perl-compatible regular expressio Line 47  PCRE - Perl-compatible regular expressio
47  .ti +5n  .ti +5n
48  .B char *\fIbuffer\fP, int \fIbuffersize\fP);  .B char *\fIbuffer\fP, int \fIbuffersize\fP);
49  .PP  .PP
 .br  
50  .B int pcre_copy_substring(const char *\fIsubject\fP, int *\fIovector\fP,  .B int pcre_copy_substring(const char *\fIsubject\fP, int *\fIovector\fP,
51  .ti +5n  .ti +5n
52  .B int \fIstringcount\fP, int \fIstringnumber\fP, char *\fIbuffer\fP,  .B int \fIstringcount\fP, int \fIstringnumber\fP, char *\fIbuffer\fP,
53  .ti +5n  .ti +5n
54  .B int \fIbuffersize\fP);  .B int \fIbuffersize\fP);
55  .PP  .PP
 .br  
56  .B int pcre_get_named_substring(const pcre *\fIcode\fP,  .B int pcre_get_named_substring(const pcre *\fIcode\fP,
57  .ti +5n  .ti +5n
58  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 69  PCRE - Perl-compatible regular expressio Line 61  PCRE - Perl-compatible regular expressio
61  .ti +5n  .ti +5n
62  .B const char **\fIstringptr\fP);  .B const char **\fIstringptr\fP);
63  .PP  .PP
 .br  
64  .B int pcre_get_stringnumber(const pcre *\fIcode\fP,  .B int pcre_get_stringnumber(const pcre *\fIcode\fP,
65  .ti +5n  .ti +5n
66  .B const char *\fIname\fP);  .B const char *\fIname\fP);
67  .PP  .PP
68  .br  .B int pcre_get_stringtable_entries(const pcre *\fIcode\fP,
69    .ti +5n
70    .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
71    .PP
72  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,
73  .ti +5n  .ti +5n
74  .B int \fIstringcount\fP, int \fIstringnumber\fP,  .B int \fIstringcount\fP, int \fIstringnumber\fP,
75  .ti +5n  .ti +5n
76  .B const char **\fIstringptr\fP);  .B const char **\fIstringptr\fP);
77  .PP  .PP
 .br  
78  .B int pcre_get_substring_list(const char *\fIsubject\fP,  .B int pcre_get_substring_list(const char *\fIsubject\fP,
79  .ti +5n  .ti +5n
80  .B int *\fIovector\fP, int \fIstringcount\fP, "const char ***\fIlistptr\fP);"  .B int *\fIovector\fP, int \fIstringcount\fP, "const char ***\fIlistptr\fP);"
81  .PP  .PP
 .br  
82  .B void pcre_free_substring(const char *\fIstringptr\fP);  .B void pcre_free_substring(const char *\fIstringptr\fP);
83  .PP  .PP
 .br  
84  .B void pcre_free_substring_list(const char **\fIstringptr\fP);  .B void pcre_free_substring_list(const char **\fIstringptr\fP);
85  .PP  .PP
 .br  
86  .B const unsigned char *pcre_maketables(void);  .B const unsigned char *pcre_maketables(void);
87  .PP  .PP
 .br  
88  .B int pcre_fullinfo(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"  .B int pcre_fullinfo(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
89  .ti +5n  .ti +5n
90  .B int \fIwhat\fP, void *\fIwhere\fP);  .B int \fIwhat\fP, void *\fIwhere\fP);
91  .PP  .PP
 .br  
92  .B int pcre_info(const pcre *\fIcode\fP, int *\fIoptptr\fP, int  .B int pcre_info(const pcre *\fIcode\fP, int *\fIoptptr\fP, int
93  .B *\fIfirstcharptr\fP);  .B *\fIfirstcharptr\fP);
94  .PP  .PP
 .br  
95  .B int pcre_refcount(pcre *\fIcode\fP, int \fIadjust\fP);  .B int pcre_refcount(pcre *\fIcode\fP, int \fIadjust\fP);
96  .PP  .PP
 .br  
97  .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);  .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);
98  .PP  .PP
 .br  
99  .B char *pcre_version(void);  .B char *pcre_version(void);
100  .PP  .PP
 .br  
101  .B void *(*pcre_malloc)(size_t);  .B void *(*pcre_malloc)(size_t);
102  .PP  .PP
 .br  
103  .B void (*pcre_free)(void *);  .B void (*pcre_free)(void *);
104  .PP  .PP
 .br  
105  .B void *(*pcre_stack_malloc)(size_t);  .B void *(*pcre_stack_malloc)(size_t);
106  .PP  .PP
 .br  
107  .B void (*pcre_stack_free)(void *);  .B void (*pcre_stack_free)(void *);
108  .PP  .PP
 .br  
109  .B int (*pcre_callout)(pcre_callout_block *);  .B int (*pcre_callout)(pcre_callout_block *);
110  .  .
111  .  .
112  .SH "PCRE API OVERVIEW"  .SH "PCRE API OVERVIEW"
113  .rs  .rs
114  .sp  .sp
115  PCRE has its own native API, which is described in this document. There is  PCRE has its own native API, which is described in this document. There are
116  also a set of wrapper functions that correspond to the POSIX regular expression  also some wrapper functions that correspond to the POSIX regular expression
117  API. These are described in the  API. These are described in the
118  .\" HREF  .\" HREF
119  \fBpcreposix\fP  \fBpcreposix\fP
# Line 160  distribution. The Line 140  distribution. The
140  .\" HREF  .\" HREF
141  \fBpcresample\fP  \fBpcresample\fP
142  .\"  .\"
143  documentation describes how to run it.  documentation describes how to compile and run it.
144  .P  .P
145  A second matching function, \fBpcre_dfa_exec()\fP, which is not  A second matching function, \fBpcre_dfa_exec()\fP, which is not
146  Perl-compatible, is also provided. This uses a different algorithm for the  Perl-compatible, is also provided. This uses a different algorithm for the
147  matching. This allows it to find all possible matches (at a given point in the  matching. The alternative algorithm finds all possible matches (at a given
148  subject), not just one. However, this algorithm does not return captured  point in the subject), and scans the subject just once. However, this algorithm
149  substrings. A description of the two matching algorithms and their advantages  does not return captured substrings. A description of the two matching
150  and disadvantages is given in the  algorithms and their advantages and disadvantages is given in the
151  .\" HREF  .\" HREF
152  \fBpcrematching\fP  \fBpcrematching\fP
153  .\"  .\"
# Line 183  matched by \fBpcre_exec()\fP. They are: Line 163  matched by \fBpcre_exec()\fP. They are:
163    \fBpcre_get_named_substring()\fP    \fBpcre_get_named_substring()\fP
164    \fBpcre_get_substring_list()\fP    \fBpcre_get_substring_list()\fP
165    \fBpcre_get_stringnumber()\fP    \fBpcre_get_stringnumber()\fP
166      \fBpcre_get_stringtable_entries()\fP
167  .sp  .sp
168  \fBpcre_free_substring()\fP and \fBpcre_free_substring_list()\fP are also  \fBpcre_free_substring()\fP and \fBpcre_free_substring_list()\fP are also
169  provided, to free the memory used for extracted strings.  provided, to free the memory used for extracted strings.
# Line 212  should be done before calling any PCRE f Line 193  should be done before calling any PCRE f
193  The global variables \fBpcre_stack_malloc\fP and \fBpcre_stack_free\fP are also  The global variables \fBpcre_stack_malloc\fP and \fBpcre_stack_free\fP are also
194  indirections to memory management functions. These special functions are used  indirections to memory management functions. These special functions are used
195  only when PCRE is compiled to use the heap for remembering data, instead of  only when PCRE is compiled to use the heap for remembering data, instead of
196  recursive function calls, when running the \fBpcre_exec()\fP function. This is  recursive function calls, when running the \fBpcre_exec()\fP function. See the
197  a non-standard way of building PCRE, for use in environments that have limited  .\" HREF
198  stacks. Because of the greater use of memory management, it runs more slowly.  \fBpcrebuild\fP
199  Separate functions are provided so that special-purpose external code can be  .\"
200  used for this case. When used, these functions are always called in a  documentation for details of how to do this. It is a non-standard way of
201  stack-like manner (last obtained, first freed), and always for memory blocks of  building PCRE, for use in environments that have limited stacks. Because of the
202  the same size.  greater use of memory management, it runs more slowly. Separate functions are
203    provided so that special-purpose external code can be used for this case. When
204    used, these functions are always called in a stack-like manner (last obtained,
205    first freed), and always for memory blocks of the same size. There is a
206    discussion about PCRE's stack usage in the
207    .\" HREF
208    \fBpcrestack\fP
209    .\"
210    documentation.
211  .P  .P
212  The global variable \fBpcre_callout\fP initially contains NULL. It can be set  The global variable \fBpcre_callout\fP initially contains NULL. It can be set
213  by the caller to a "callout" function, which PCRE will then call at specified  by the caller to a "callout" function, which PCRE will then call at specified
# Line 229  points during a matching operation. Deta Line 218  points during a matching operation. Deta
218  documentation.  documentation.
219  .  .
220  .  .
221    .\" HTML <a name="newlines"></a>
222    .SH NEWLINES
223    .rs
224    .sp
225    PCRE supports five different conventions for indicating line breaks in
226    strings: a single CR (carriage return) character, a single LF (linefeed)
227    character, the two-character sequence CRLF, any of the three preceding, or any
228    Unicode newline sequence. The Unicode newline sequences are the three just
229    mentioned, plus the single characters VT (vertical tab, U+000B), FF (formfeed,
230    U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
231    (paragraph separator, U+2029).
232    .P
233    Each of the first three conventions is used by at least one operating system as
234    its standard newline sequence. When PCRE is built, a default can be specified.
235    The default default is LF, which is the Unix standard. When PCRE is run, the
236    default can be overridden, either when a pattern is compiled, or when it is
237    matched.
238    .P
239    At compile time, the newline convention can be specified by the \fIoptions\fP
240    argument of \fBpcre_compile()\fP, or it can be specified by special text at the
241    start of the pattern itself; this overrides any other settings. See the
242    .\" HREF
243    \fBpcrepattern\fP
244    .\"
245    page for details of the special character sequences.
246    .P
247    In the PCRE documentation the word "newline" is used to mean "the character or
248    pair of characters that indicate a line break". The choice of newline
249    convention affects the handling of the dot, circumflex, and dollar
250    metacharacters, the handling of #-comments in /x mode, and, when CRLF is a
251    recognized line ending sequence, the match position advancement for a
252    non-anchored pattern. There is more detail about this in the
253    .\" HTML <a href="#execoptions">
254    .\" </a>
255    section on \fBpcre_exec()\fP options
256    .\"
257    below.
258    .P
259    The choice of newline convention does not affect the interpretation of
260    the \en or \er escape sequences, nor does it affect what \eR matches, which is
261    controlled in a similar way, but by separate options.
262    .
263    .
264  .SH MULTITHREADING  .SH MULTITHREADING
265  .rs  .rs
266  .sp  .sp
# Line 250  which it was compiled. Details are given Line 282  which it was compiled. Details are given
282  .\" HREF  .\" HREF
283  \fBpcreprecompile\fP  \fBpcreprecompile\fP
284  .\"  .\"
285  documentation.  documentation. However, compiling a regular expression with one version of PCRE
286    for use with a different version is not guaranteed to work and may cause
287    crashes.
288  .  .
289  .  .
290  .SH "CHECKING BUILD-TIME OPTIONS"  .SH "CHECKING BUILD-TIME OPTIONS"
# Line 281  properties is available; otherwise it is Line 315  properties is available; otherwise it is
315  .sp  .sp
316    PCRE_CONFIG_NEWLINE    PCRE_CONFIG_NEWLINE
317  .sp  .sp
318  The output is an integer that is set to the value of the code that is used for  The output is an integer whose value specifies the default character sequence
319  the newline character. It is either linefeed (10) or carriage return (13), and  that is recognized as meaning "newline". The four values that are supported
320  should normally be the standard character for your operating system.  are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF, and -1 for ANY.
321    Though they are derived from ASCII, the same values are returned in EBCDIC
322    environments. The default should normally correspond to the standard sequence
323    for your operating system.
324    .sp
325      PCRE_CONFIG_BSR
326    .sp
327    The output is an integer whose value indicates what character sequences the \eR
328    escape sequence matches by default. A value of 0 means that \eR matches any
329    Unicode line ending sequence; a value of 1 means that \eR matches only CR, LF,
330    or CRLF. The default can be overridden when a pattern is compiled or matched.
331  .sp  .sp
332    PCRE_CONFIG_LINK_SIZE    PCRE_CONFIG_LINK_SIZE
333  .sp  .sp
# Line 305  documentation. Line 349  documentation.
349  .sp  .sp
350    PCRE_CONFIG_MATCH_LIMIT    PCRE_CONFIG_MATCH_LIMIT
351  .sp  .sp
352  The output is an integer that gives the default limit for the number of  The output is a long integer that gives the default limit for the number of
353  internal matching function calls in a \fBpcre_exec()\fP execution. Further  internal matching function calls in a \fBpcre_exec()\fP execution. Further
354  details are given with \fBpcre_exec()\fP below.  details are given with \fBpcre_exec()\fP below.
355  .sp  .sp
356    PCRE_CONFIG_MATCH_LIMIT_RECURSION    PCRE_CONFIG_MATCH_LIMIT_RECURSION
357  .sp  .sp
358  The output is an integer that gives the default limit for the depth of  The output is a long integer that gives the default limit for the depth of
359  recursion when calling the internal matching function in a \fBpcre_exec()\fP  recursion when calling the internal matching function in a \fBpcre_exec()\fP
360  execution. Further details are given with \fBpcre_exec()\fP below.  execution. Further details are given with \fBpcre_exec()\fP below.
361  .sp  .sp
# Line 353  The pattern is a C string terminated by Line 397  The pattern is a C string terminated by
397  via \fBpcre_malloc\fP is returned. This contains the compiled code and related  via \fBpcre_malloc\fP is returned. This contains the compiled code and related
398  data. The \fBpcre\fP type is defined for the returned block; this is a typedef  data. The \fBpcre\fP type is defined for the returned block; this is a typedef
399  for a structure whose contents are not externally defined. It is up to the  for a structure whose contents are not externally defined. It is up to the
400  caller to free the memory when it is no longer required.  caller to free the memory (via \fBpcre_free\fP) when it is no longer required.
401  .P  .P
402  Although the compiled code of a PCRE regex is relocatable, that is, it does not  Although the compiled code of a PCRE regex is relocatable, that is, it does not
403  depend on memory location, the complete \fBpcre\fP data block is not  depend on memory location, the complete \fBpcre\fP data block is not
404  fully relocatable, because it may contain a copy of the \fItableptr\fP  fully relocatable, because it may contain a copy of the \fItableptr\fP
405  argument, which is an address (see below).  argument, which is an address (see below).
406  .P  .P
407  The \fIoptions\fP argument contains independent bits that affect the  The \fIoptions\fP argument contains various bit settings that affect the
408  compilation. It should be zero if no options are required. The available  compilation. It should be zero if no options are required. The available
409  options are described below. Some of them, in particular, those that are  options are described below. Some of them, in particular, those that are
410  compatible with Perl, can also be set and unset from within the pattern (see  compatible with Perl, can also be set and unset from within the pattern (see
# Line 370  the detailed description in the Line 414  the detailed description in the
414  .\"  .\"
415  documentation). For these options, the contents of the \fIoptions\fP argument  documentation). For these options, the contents of the \fIoptions\fP argument
416  specifies their initial settings at the start of compilation and execution. The  specifies their initial settings at the start of compilation and execution. The
417  PCRE_ANCHORED option can be set at the time of matching as well as at compile  PCRE_ANCHORED and PCRE_NEWLINE_\fIxxx\fP options can be set at the time of
418  time.  matching as well as at compile time.
419  .P  .P
420  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
421  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
# Line 426  facility, see the Line 470  facility, see the
470  .\"  .\"
471  documentation.  documentation.
472  .sp  .sp
473      PCRE_BSR_ANYCRLF
474      PCRE_BSR_UNICODE
475    .sp
476    These options (which are mutually exclusive) control what the \eR escape
477    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
478    match any Unicode newline sequence. The default is specified when PCRE is
479    built. It can be overridden from within the pattern, or by setting an option
480    when a compiled pattern is matched.
481    .sp
482    PCRE_CASELESS    PCRE_CASELESS
483  .sp  .sp
484  If this bit is set, letters in the pattern match both upper and lower case  If this bit is set, letters in the pattern match both upper and lower case
# Line 442  with UTF-8 support. Line 495  with UTF-8 support.
495  .sp  .sp
496  If this bit is set, a dollar metacharacter in the pattern matches only at the  If this bit is set, a dollar metacharacter in the pattern matches only at the
497  end of the subject string. Without this option, a dollar also matches  end of the subject string. Without this option, a dollar also matches
498  immediately before the final character if it is a newline (but not before any  immediately before a newline at the end of the string (but not before any other
499  other newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is  newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is set.
500  set. There is no equivalent to this option in Perl, and no way to set it within  There is no equivalent to this option in Perl, and no way to set it within a
501  a pattern.  pattern.
502  .sp  .sp
503    PCRE_DOTALL    PCRE_DOTALL
504  .sp  .sp
505  If this bit is set, a dot metacharater in the pattern matches all characters,  If this bit is set, a dot metacharater in the pattern matches all characters,
506  including newlines. Without it, newlines are excluded. This option is  including those that indicate newline. Without it, a dot does not match when
507  equivalent to Perl's /s option, and it can be changed within a pattern by a  the current position is at a newline. This option is equivalent to Perl's /s
508  (?s) option setting. A negative class such as [^a] always matches a newline  option, and it can be changed within a pattern by a (?s) option setting. A
509  character, independent of the setting of this option.  negative class such as [^a] always matches newline characters, independent of
510    the setting of this option.
511    .sp
512      PCRE_DUPNAMES
513    .sp
514    If this bit is set, names used to identify capturing subpatterns need not be
515    unique. This can be helpful for certain types of pattern when it is known that
516    only one instance of the named subpattern can ever be matched. There are more
517    details of named subpatterns below; see also the
518    .\" HREF
519    \fBpcrepattern\fP
520    .\"
521    documentation.
522  .sp  .sp
523    PCRE_EXTENDED    PCRE_EXTENDED
524  .sp  .sp
525  If this bit is set, whitespace data characters in the pattern are totally  If this bit is set, whitespace data characters in the pattern are totally
526  ignored except when escaped or inside a character class. Whitespace does not  ignored except when escaped or inside a character class. Whitespace does not
527  include the VT character (code 11). In addition, characters between an  include the VT character (code 11). In addition, characters between an
528  unescaped # outside a character class and the next newline character,  unescaped # outside a character class and the next newline, inclusive, are also
529  inclusive, are also ignored. This is equivalent to Perl's /x option, and it can  ignored. This is equivalent to Perl's /x option, and it can be changed within a
530  be changed within a pattern by a (?x) option setting.  pattern by a (?x) option setting.
531  .P  .P
532  This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
533  Note, however, that this applies only to data characters. Whitespace characters  Note, however, that this applies only to data characters. Whitespace characters
# Line 476  that is incompatible with Perl, but it i Line 541  that is incompatible with Perl, but it i
541  set, any backslash in a pattern that is followed by a letter that has no  set, any backslash in a pattern that is followed by a letter that has no
542  special meaning causes an error, thus reserving these combinations for future  special meaning causes an error, thus reserving these combinations for future
543  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
544  special meaning is treated as a literal. There are at present no other features  special meaning is treated as a literal. (Perl can, however, be persuaded to
545  controlled by this option. It can also be set by a (?X) option setting within a  give a warning for this.) There are at present no other features controlled by
546  pattern.  this option. It can also be set by a (?X) option setting within a pattern.
547  .sp  .sp
548    PCRE_FIRSTLINE    PCRE_FIRSTLINE
549  .sp  .sp
550  If this option is set, an unanchored pattern is required to match before or at  If this option is set, an unanchored pattern is required to match before or at
551  the first newline character in the subject string, though the matched text may  the first newline in the subject string, though the matched text may continue
552  continue over the newline.  over the newline.
553    .sp
554      PCRE_JAVASCRIPT_COMPAT
555    .sp
556    If this option is set, PCRE's behaviour is changed in some ways so that it is
557    compatible with JavaScript rather than Perl. The changes are as follows:
558    .P
559    (1) A lone closing square bracket in a pattern causes a compile-time error,
560    because this is illegal in JavaScript (by default it is treated as a data
561    character). Thus, the pattern AB]CD becomes illegal when this option is set.
562    .P
563    (2) At run time, a back reference to an unset subpattern group matches an empty
564    string (by default this causes the current matching alternative to fail). A
565    pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
566    an "a" in the subject), whereas it fails by default, for Perl compatibility.
567  .sp  .sp
568    PCRE_MULTILINE    PCRE_MULTILINE
569  .sp  .sp
# Line 496  terminating newline (unless PCRE_DOLLAR_ Line 575  terminating newline (unless PCRE_DOLLAR_
575  Perl.  Perl.
576  .P  .P
577  When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs  When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs
578  match immediately following or immediately before any newline in the subject  match immediately following or immediately before internal newlines in the
579  string, respectively, as well as at the very start and end. This is equivalent  subject string, respectively, as well as at the very start and end. This is
580  to Perl's /m option, and it can be changed within a pattern by a (?m) option  equivalent to Perl's /m option, and it can be changed within a pattern by a
581  setting. If there are no "\en" characters in a subject string, or no  (?m) option setting. If there are no newlines in a subject string, or no
582  occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect.  occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect.
583  .sp  .sp
584      PCRE_NEWLINE_CR
585      PCRE_NEWLINE_LF
586      PCRE_NEWLINE_CRLF
587      PCRE_NEWLINE_ANYCRLF
588      PCRE_NEWLINE_ANY
589    .sp
590    These options override the default newline definition that was chosen when PCRE
591    was built. Setting the first or the second specifies that a newline is
592    indicated by a single character (CR or LF, respectively). Setting
593    PCRE_NEWLINE_CRLF specifies that a newline is indicated by the two-character
594    CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three
595    preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
596    that any Unicode newline sequence should be recognized. The Unicode newline
597    sequences are the three just mentioned, plus the single characters VT (vertical
598    tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line
599    separator, U+2028), and PS (paragraph separator, U+2029). The last two are
600    recognized only in UTF-8 mode.
601    .P
602    The newline setting in the options word uses three bits that are treated
603    as a number, giving eight possibilities. Currently only six are used (default
604    plus the five values above). This means that if you set more than one newline
605    option, the combination may or may not be sensible. For example,
606    PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but
607    other combinations may yield unused numbers and cause an error.
608    .P
609    The only time that a line break is specially recognized when compiling a
610    pattern is if PCRE_EXTENDED is set, and an unescaped # outside a character
611    class is encountered. This indicates a comment that lasts until after the next
612    line break sequence. In other circumstances, line break sequences are treated
613    as literal data, except that in PCRE_EXTENDED mode, both CR and LF are treated
614    as whitespace characters and are therefore ignored.
615    .P
616    The newline option that is set at compile time becomes the default that is used
617    for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.
618    .sp
619    PCRE_NO_AUTO_CAPTURE    PCRE_NO_AUTO_CAPTURE
620  .sp  .sp
621  If this option is set, it disables the use of numbered capturing parentheses in  If this option is set, it disables the use of numbered capturing parentheses in
# Line 536  page. Line 650  page.
650    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
651  .sp  .sp
652  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
653  automatically checked. If an invalid UTF-8 sequence of bytes is found,  automatically checked. There is a discussion about the
654  \fBpcre_compile()\fP returns an error. If you already know that your pattern is  .\" HTML <a href="pcre.html#utf8strings">
655  valid, and you want to skip this check for performance reasons, you can set the  .\" </a>
656  PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid  validity of UTF-8 strings
657  UTF-8 string as a pattern is undefined. It may cause your program to crash.  .\"
658  Note that this option can also be passed to \fBpcre_exec()\fP and  in the main
659  \fBpcre_dfa_exec()\fP, to suppress the UTF-8 validity checking of subject  .\" HREF
660  strings.  \fBpcre\fP
661    .\"
662    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_compile()\fP
663    returns an error. If you already know that your pattern is valid, and you want
664    to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
665    option. When it is set, the effect of passing an invalid UTF-8 string as a
666    pattern is undefined. It may cause your program to crash. Note that this option
667    can also be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress
668    the UTF-8 validity checking of subject strings.
669  .  .
670  .  .
671  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 551  strings. Line 673  strings.
673  .sp  .sp
674  The following table lists the error codes than may be returned by  The following table lists the error codes than may be returned by
675  \fBpcre_compile2()\fP, along with the error messages that may be returned by  \fBpcre_compile2()\fP, along with the error messages that may be returned by
676  both compiling functions.  both compiling functions. As PCRE has developed, some error codes have fallen
677    out of use. To avoid confusion, they have not been re-used.
678  .sp  .sp
679     0  no error     0  no error
680     1  \e at end of pattern     1  \e at end of pattern
# Line 563  both compiling functions. Line 686  both compiling functions.
686     7  invalid escape sequence in character class     7  invalid escape sequence in character class
687     8  range out of order in character class     8  range out of order in character class
688     9  nothing to repeat     9  nothing to repeat
689    10  operand of unlimited repeat could match the empty string    10  [this code is not in use]
690    11  internal error: unexpected repeat    11  internal error: unexpected repeat
691    12  unrecognized character after (?    12  unrecognized character after (? or (?-
692    13  POSIX named classes are supported only within a class    13  POSIX named classes are supported only within a class
693    14  missing )    14  missing )
694    15  reference to non-existent subpattern    15  reference to non-existent subpattern
695    16  erroffset passed as NULL    16  erroffset passed as NULL
696    17  unknown option bit(s) set    17  unknown option bit(s) set
697    18  missing ) after comment    18  missing ) after comment
698    19  parentheses nested too deeply    19  [this code is not in use]
699    20  regular expression too large    20  regular expression is too large
700    21  failed to get memory    21  failed to get memory
701    22  unmatched parentheses    22  unmatched parentheses
702    23  internal error: code overflow    23  internal error: code overflow
703    24  unrecognized character after (?<    24  unrecognized character after (?<
704    25  lookbehind assertion is not fixed length    25  lookbehind assertion is not fixed length
705    26  malformed number after (?(    26  malformed number or name after (?(
706    27  conditional group contains more than two branches    27  conditional group contains more than two branches
707    28  assertion expected after (?(    28  assertion expected after (?(
708    29  (?R or (?digits must be followed by )    29  (?R or (?[+-]digits must be followed by )
709    30  unknown POSIX class name    30  unknown POSIX class name
710    31  POSIX collating elements are not supported    31  POSIX collating elements are not supported
711    32  this version of PCRE is not compiled with PCRE_UTF8 support    32  this version of PCRE is not compiled with PCRE_UTF8 support
712    33  spare error    33  [this code is not in use]
713    34  character value in \ex{...} sequence is too large    34  character value in \ex{...} sequence is too large
714    35  invalid condition (?(0)    35  invalid condition (?(0)
715    36  \eC not allowed in lookbehind assertion    36  \eC not allowed in lookbehind assertion
# Line 595  both compiling functions. Line 718  both compiling functions.
718    39  closing ) for (?C expected    39  closing ) for (?C expected
719    40  recursive call could loop indefinitely    40  recursive call could loop indefinitely
720    41  unrecognized character after (?P    41  unrecognized character after (?P
721    42  syntax error after (?P    42  syntax error in subpattern name (missing terminator)
722    43  two named groups have the same name    43  two named subpatterns have the same name
723    44  invalid UTF-8 string    44  invalid UTF-8 string
724    45  support for \eP, \ep, and \eX has not been compiled    45  support for \eP, \ep, and \eX has not been compiled
725    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
726    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
727      48  subpattern name is too long (maximum 32 characters)
728      49  too many named subpatterns (maximum 10000)
729      50  [this code is not in use]
730      51  octal value is greater than \e377 (not in UTF-8 mode)
731      52  internal error: overran compiling workspace
732      53  internal error: previously-checked referenced subpattern not found
733      54  DEFINE group contains more than one branch
734      55  repeating a DEFINE group is not allowed
735      56  inconsistent NEWLINE options
736      57  \eg is not followed by a braced, angle-bracketed, or quoted
737            name/number or by a plain number
738      58  a numbered reference must not be zero
739      59  (*VERB) with an argument is not supported
740      60  (*VERB) not recognized
741      61  number is too big
742      62  subpattern name expected
743      63  digit expected after (?+
744      64  ] is an invalid data character in JavaScript compatibility mode
745    .sp
746    The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
747    be used if the limits were changed when PCRE was built.
748  .  .
749  .  .
750  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
# Line 660  bytes is created. Line 804  bytes is created.
804  .SH "LOCALE SUPPORT"  .SH "LOCALE SUPPORT"
805  .rs  .rs
806  .sp  .sp
807  PCRE handles caseless matching, and determines whether characters are letters  PCRE handles caseless matching, and determines whether characters are letters,
808  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
809  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
810  less than 128. Higher-valued codes never match escapes such as \ew or \ed, but  less than 128. Higher-valued codes never match escapes such as \ew or \ed, but
811  can be tested with \ep if PCRE is built with Unicode character property  can be tested with \ep if PCRE is built with Unicode character property
812  support. The use of locales with Unicode is discouraged.  support. The use of locales with Unicode is discouraged. If you are handling
813  .P  characters with codes greater than 128, you should either use UTF-8 and
814  An internal set of tables is created in the default C locale when PCRE is  Unicode, or use locales, but not try to mix the two.
815  built. This is used when the final argument of \fBpcre_compile()\fP is NULL,  .P
816  and is sufficient for many applications. An alternative set of tables can,  PCRE contains an internal set of tables that are used when the final argument
817  however, be supplied. These may be created in a different locale from the  of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.
818  default. As more and more applications change to using Unicode, the need for  Normally, the internal tables recognize only ASCII characters. However, when
819  this locale support is expected to die away.  PCRE is built, it is possible to cause the internal tables to be rebuilt in the
820    default "C" locale of the local system, which may cause them to be different.
821    .P
822    The internal tables can always be overridden by tables supplied by the
823    application that calls PCRE. These may be created in a different locale from
824    the default. As more and more applications change to using Unicode, the need
825    for this locale support is expected to die away.
826  .P  .P
827  External tables are built by calling the \fBpcre_maketables()\fP function,  External tables are built by calling the \fBpcre_maketables()\fP function,
828  which has no arguments, in the relevant locale. The result can then be passed  which has no arguments, in the relevant locale. The result can then be passed
# Line 685  the following code could be used: Line 835  the following code could be used:
835    tables = pcre_maketables();    tables = pcre_maketables();
836    re = pcre_compile(..., tables);    re = pcre_compile(..., tables);
837  .sp  .sp
838    The locale name "fr_FR" is used on Linux and other Unix-like systems; if you
839    are using Windows, the name for the French locale is "french".
840    .P
841  When \fBpcre_maketables()\fP runs, the tables are built in memory that is  When \fBpcre_maketables()\fP runs, the tables are built in memory that is
842  obtained via \fBpcre_malloc\fP. It is the caller's responsibility to ensure  obtained via \fBpcre_malloc\fP. It is the caller's responsibility to ensure
843  that the memory containing the tables remains available for as long as it is  that the memory containing the tables remains available for as long as it is
# Line 731  check against passing an arbitrary memor Line 884  check against passing an arbitrary memor
884  \fBpcre_fullinfo()\fP, to obtain the length of the compiled pattern:  \fBpcre_fullinfo()\fP, to obtain the length of the compiled pattern:
885  .sp  .sp
886    int rc;    int rc;
887    unsigned long int length;    size_t length;
888    rc = pcre_fullinfo(    rc = pcre_fullinfo(
889      re,               /* result of pcre_compile() */      re,               /* result of pcre_compile() */
890      pe,               /* result of pcre_study(), or NULL */      pe,               /* result of pcre_study(), or NULL */
# Line 763  a NULL table pointer. Line 916  a NULL table pointer.
916    PCRE_INFO_FIRSTBYTE    PCRE_INFO_FIRSTBYTE
917  .sp  .sp
918  Return information about the first byte of any matched string, for a  Return information about the first byte of any matched string, for a
919  non-anchored pattern. (This option used to be called PCRE_INFO_FIRSTCHAR; the  non-anchored pattern. The fourth argument should point to an \fBint\fP
920  old name is still recognized for backwards compatibility.)  variable. (This option used to be called PCRE_INFO_FIRSTCHAR; the old name is
921    still recognized for backwards compatibility.)
922  .P  .P
923  If there is a fixed first byte, for example, from a pattern such as  If there is a fixed first byte, for example, from a pattern such as
924  (cat|cow|coyote), it is returned in the integer pointed to by \fIwhere\fP.  (cat|cow|coyote), its value is returned. Otherwise, if either
 Otherwise, if either  
925  .sp  .sp
926  (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch  (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
927  starts with "^", or  starts with "^", or
# Line 787  table indicating a fixed set of bytes fo Line 940  table indicating a fixed set of bytes fo
940  string, a pointer to the table is returned. Otherwise NULL is returned. The  string, a pointer to the table is returned. Otherwise NULL is returned. The
941  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
942  .sp  .sp
943      PCRE_INFO_HASCRORLF
944    .sp
945    Return 1 if the pattern contains any explicit matches for CR or LF characters,
946    otherwise 0. The fourth argument should point to an \fBint\fP variable. An
947    explicit match is either a literal CR or LF character, or \er or \en.
948    .sp
949      PCRE_INFO_JCHANGED
950    .sp
951    Return 1 if the (?J) or (?-J) option setting is used in the pattern, otherwise
952    0. The fourth argument should point to an \fBint\fP variable. (?J) and
953    (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
954    .sp
955    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
956  .sp  .sp
957  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 803  is -1. Line 968  is -1.
968  .sp  .sp
969  PCRE supports the use of named as well as numbered capturing parentheses. The  PCRE supports the use of named as well as numbered capturing parentheses. The
970  names are just an additional way of identifying the parentheses, which still  names are just an additional way of identifying the parentheses, which still
971  acquire numbers. A convenience function called \fBpcre_get_named_substring()\fP  acquire numbers. Several convenience functions such as
972  is provided for extracting an individual captured substring by name. It is also  \fBpcre_get_named_substring()\fP are provided for extracting captured
973  possible to extract the data directly, by first converting the name to a number  substrings by name. It is also possible to extract the data directly, by first
974  in order to access the correct pointers in the output vector (described with  converting the name to a number in order to access the correct pointers in the
975  \fBpcre_exec()\fP below). To do the conversion, you need to use the  output vector (described with \fBpcre_exec()\fP below). To do the conversion,
976  name-to-number map, which is described by these three values.  you need to use the name-to-number map, which is described by these three
977    values.
978  .P  .P
979  The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT gives  The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT gives
980  the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each  the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each
# Line 817  length of the longest name. PCRE_INFO_NA Line 983  length of the longest name. PCRE_INFO_NA
983  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
984  are the number of the capturing parenthesis, most significant byte first. The  are the number of the capturing parenthesis, most significant byte first. The
985  rest of the entry is the corresponding name, zero terminated. The names are in  rest of the entry is the corresponding name, zero terminated. The names are in
986  alphabetical order. For example, consider the following pattern (assume  alphabetical order. When PCRE_DUPNAMES is set, duplicate names are in order of
987    their parentheses numbers. For example, consider the following pattern (assume
988  PCRE_EXTENDED is set, so white space - including newlines - is ignored):  PCRE_EXTENDED is set, so white space - including newlines - is ignored):
989  .sp  .sp
990  .\" JOIN  .\" JOIN
991    (?P<date> (?P<year>(\ed\ed)?\ed\ed) -    (?<date> (?<year>(\ed\ed)?\ed\ed) -
992    (?P<month>\ed\ed) - (?P<day>\ed\ed) )    (?<month>\ed\ed) - (?<day>\ed\ed) )
993  .sp  .sp
994  There are four named subpatterns, so the table has four entries, and each entry  There are four named subpatterns, so the table has four entries, and each entry
995  in the table is eight bytes long. The table is as follows, with non-printing  in the table is eight bytes long. The table is as follows, with non-printing
# Line 834  bytes shows in hexadecimal, and undefine Line 1001  bytes shows in hexadecimal, and undefine
1001    00 02 y  e  a  r  00 ??    00 02 y  e  a  r  00 ??
1002  .sp  .sp
1003  When writing code to extract data from named subpatterns using the  When writing code to extract data from named subpatterns using the
1004  name-to-number map, remember that the length of each entry is likely to be  name-to-number map, remember that the length of the entries is likely to be
1005  different for each compiled pattern.  different for each compiled pattern.
1006  .sp  .sp
1007      PCRE_INFO_OKPARTIAL
1008    .sp
1009    Return 1 if the pattern can be used for partial matching, otherwise 0. The
1010    fourth argument should point to an \fBint\fP variable. The
1011    .\" HREF
1012    \fBpcrepartial\fP
1013    .\"
1014    documentation lists the restrictions that apply to patterns when partial
1015    matching is used.
1016    .sp
1017    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1018  .sp  .sp
1019  Return a copy of the options with which the pattern was compiled. The fourth  Return a copy of the options with which the pattern was compiled. The fourth
1020  argument should point to an \fBunsigned long int\fP variable. These option bits  argument should point to an \fBunsigned long int\fP variable. These option bits
1021  are those specified in the call to \fBpcre_compile()\fP, modified by any  are those specified in the call to \fBpcre_compile()\fP, modified by any
1022  top-level option settings within the pattern itself.  top-level option settings at the start of the pattern itself. In other words,
1023    they are the options that will be in force when matching starts. For example,
1024    if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the
1025    result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED.
1026  .P  .P
1027  A pattern is automatically anchored by PCRE if all of its top-level  A pattern is automatically anchored by PCRE if all of its top-level
1028  alternatives begin with one of the following:  alternatives begin with one of the following:
# Line 1053  called. See the Line 1233  called. See the
1233  .\"  .\"
1234  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1235  .  .
1236    .\" HTML <a name="execoptions"></a>
1237  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
1238  .rs  .rs
1239  .sp  .sp
1240  The unused bits of the \fIoptions\fP argument for \fBpcre_exec()\fP must be  The unused bits of the \fIoptions\fP argument for \fBpcre_exec()\fP must be
1241  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NOTBOL,  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,
1242  PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_START_OPTIMIZE,
1243    PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.
1244  .sp  .sp
1245    PCRE_ANCHORED    PCRE_ANCHORED
1246  .sp  .sp
# Line 1067  matching position. If a pattern was comp Line 1249  matching position. If a pattern was comp
1249  to be anchored by virtue of its contents, it cannot be made unachored at  to be anchored by virtue of its contents, it cannot be made unachored at
1250  matching time.  matching time.
1251  .sp  .sp
1252      PCRE_BSR_ANYCRLF
1253      PCRE_BSR_UNICODE
1254    .sp
1255    These options (which are mutually exclusive) control what the \eR escape
1256    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1257    match any Unicode newline sequence. These options override the choice that was
1258    made or defaulted when the pattern was compiled.
1259    .sp
1260      PCRE_NEWLINE_CR
1261      PCRE_NEWLINE_LF
1262      PCRE_NEWLINE_CRLF
1263      PCRE_NEWLINE_ANYCRLF
1264      PCRE_NEWLINE_ANY
1265    .sp
1266    These options override the newline definition that was chosen or defaulted when
1267    the pattern was compiled. For details, see the description of
1268    \fBpcre_compile()\fP above. During matching, the newline choice affects the
1269    behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1270    the way the match position is advanced after a match failure for an unanchored
1271    pattern.
1272    .P
1273    When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a
1274    match attempt for an unanchored pattern fails when the current position is at a
1275    CRLF sequence, and the pattern contains no explicit matches for CR or LF
1276    characters, the match position is advanced by two characters instead of one, in
1277    other words, to after the CRLF.
1278    .P
1279    The above rule is a compromise that makes the most common cases work as
1280    expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1281    set), it does not match the string "\er\enA" because, after failing at the
1282    start, it skips both the CR and the LF before retrying. However, the pattern
1283    [\er\en]A does match that string, because it contains an explicit CR or LF
1284    reference, and so advances only by one character after the first failure.
1285    .P
1286    An explicit match for CR of LF is either a literal appearance of one of those
1287    characters, or one of the \er or \en escape sequences. Implicit matches such as
1288    [^X] do not count, nor does \es (which includes CR and LF in the characters
1289    that it matches).
1290    .P
1291    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1292    valid newline sequence and explicit \er or \en escapes appear in the pattern.
1293    .sp
1294    PCRE_NOTBOL    PCRE_NOTBOL
1295  .sp  .sp
1296  This option specifies that first character of the subject string is not the  This option specifies that first character of the subject string is not the
# Line 1103  PCRE_NOTEMPTY and PCRE_ANCHORED, and the Line 1327  PCRE_NOTEMPTY and PCRE_ANCHORED, and the
1327  starting offset (see below) and trying an ordinary match again. There is some  starting offset (see below) and trying an ordinary match again. There is some
1328  code that demonstrates how to do this in the \fIpcredemo.c\fP sample program.  code that demonstrates how to do this in the \fIpcredemo.c\fP sample program.
1329  .sp  .sp
1330      PCRE_NO_START_OPTIMIZE
1331    .sp
1332    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1333    a match, in order to speed up the process. For example, if it is known that a
1334    match must start with a specific character, it searches the subject for that
1335    character, and fails immediately if it cannot find it, without actually running
1336    the main matching function. When callouts are in use, these optimizations can
1337    cause them to be skipped. This option disables the "start-up" optimizations,
1338    causing performance to suffer, but ensuring that the callouts do occur.
1339    .sp
1340    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1341  .sp  .sp
1342  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8
1343  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1344  The value of \fIstartoffset\fP is also checked to ensure that it points to the  The value of \fIstartoffset\fP is also checked to ensure that it points to the
1345  start of a UTF-8 character. If an invalid UTF-8 sequence of bytes is found,  start of a UTF-8 character. There is a discussion about the validity of UTF-8
1346  \fBpcre_exec()\fP returns the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP  strings in the
1347  contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.  .\" HTML <a href="pcre.html#utf8strings">
1348    .\" </a>
1349    section on UTF-8 support
1350    .\"
1351    in the main
1352    .\" HREF
1353    \fBpcre\fP
1354    .\"
1355    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1356    the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains an invalid value,
1357    PCRE_ERROR_BADUTF8_OFFSET is returned.
1358  .P  .P
1359  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
1360  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when
# Line 1140  documentation. Line 1384  documentation.
1384  .rs  .rs
1385  .sp  .sp
1386  The subject string is passed to \fBpcre_exec()\fP as a pointer in  The subject string is passed to \fBpcre_exec()\fP as a pointer in
1387  \fIsubject\fP, a length in \fIlength\fP, and a starting byte offset in  \fIsubject\fP, a length (in bytes) in \fIlength\fP, and a starting byte offset
1388  \fIstartoffset\fP. In UTF-8 mode, the byte offset must point to the start of a  in \fIstartoffset\fP. In UTF-8 mode, the byte offset must point to the start of
1389  UTF-8 character. Unlike the pattern string, the subject may contain binary zero  a UTF-8 character. Unlike the pattern string, the subject may contain binary
1390  bytes. When the starting offset is zero, the search for a match starts at the  zero bytes. When the starting offset is zero, the search for a match starts at
1391  beginning of the subject, and this is by far the most common case.  the beginning of the subject, and this is by far the most common case.
1392  .P  .P
1393  A non-zero starting offset is useful when searching for another match in the  A non-zero starting offset is useful when searching for another match in the
1394  same subject by calling \fBpcre_exec()\fP again after a previous success.  same subject by calling \fBpcre_exec()\fP again after a previous success.
# Line 1178  pattern. Following the usage in Jeffrey Line 1422  pattern. Following the usage in Jeffrey
1422  a fragment of a pattern that picks out a substring. PCRE supports several other  a fragment of a pattern that picks out a substring. PCRE supports several other
1423  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1424  .P  .P
1425  Captured substrings are returned to the caller via a vector of integer offsets  Captured substrings are returned to the caller via a vector of integers whose
1426  whose address is passed in \fIovector\fP. The number of elements in the vector  address is passed in \fIovector\fP. The number of elements in the vector is
1427  is passed in \fIovecsize\fP, which must be a non-negative number. \fBNote\fP:  passed in \fIovecsize\fP, which must be a non-negative number. \fBNote\fP: this
1428  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1429  .P  .P
1430  The first two-thirds of the vector is used to pass back captured substrings,  The first two-thirds of the vector is used to pass back captured substrings,
1431  each substring using a pair of integers. The remaining third of the vector is  each substring using a pair of integers. The remaining third of the vector is
1432  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1433  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1434  \fIovecsize\fP should always be a multiple of three. If it is not, it is  \fIovecsize\fP should always be a multiple of three. If it is not, it is
1435  rounded down.  rounded down.
1436  .P  .P
1437  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1438  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1439  continuing up to two-thirds of its length at the most. The first element of a  continuing up to two-thirds of its length at the most. The first element of
1440  pair is set to the offset of the first character in a substring, and the second  each pair is set to the byte offset of the first character in a substring, and
1441  is set to the offset of the first character after the end of a substring. The  the second is set to the byte offset of the first character after the end of a
1442  first pair, \fIovector[0]\fP and \fIovector[1]\fP, identify the portion of the  substring. \fBNote\fP: these values are always byte offsets, even in UTF-8
1443  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1444  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1445  is the number of pairs that have been set. If there are no capturing  The first pair of integers, \fIovector[0]\fP and \fIovector[1]\fP, identify the
1446  subpatterns, the return value from a successful match is 1, indicating that  portion of the subject string matched by the entire pattern. The next pair is
1447  just the first pair of offsets has been set.  used for the first capturing subpattern, and so on. The value returned by
1448  .P  \fBpcre_exec()\fP is one more than the highest numbered pair that has been set.
1449  Some convenience functions are provided for extracting the captured substrings  For example, if two substrings have been captured, the returned value is 3. If
1450  as separate strings. These are described in the following section.  there are no capturing subpatterns, the return value from a successful match is
1451  .P  1, indicating that just the first pair of offsets has been set.
 It is possible for an capturing subpattern number \fIn+1\fP to match some  
 part of the subject when subpattern \fIn\fP has not been used at all. For  
 example, if the string "abc" is matched against the pattern (a|(z))(bc)  
 subpatterns 1 and 3 are matched, but 2 is not. When this happens, both offset  
 values corresponding to the unused subpattern are set to -1.  
1452  .P  .P
1453  If a capturing subpattern is matched repeatedly, it is the last portion of the  If a capturing subpattern is matched repeatedly, it is the last portion of the
1454  string that it matched that is returned.  string that it matched that is returned.
1455  .P  .P
1456  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
1457  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
1458  returns a value of zero. In particular, if the substring offsets are not of  returns a value of zero. If the substring offsets are not of interest,
1459  interest, \fBpcre_exec()\fP may be called with \fIovector\fP passed as NULL and  \fBpcre_exec()\fP may be called with \fIovector\fP passed as NULL and
1460  \fIovecsize\fP as zero. However, if the pattern contains back references and  \fIovecsize\fP as zero. However, if the pattern contains back references and
1461  the \fIovector\fP is not big enough to remember the related substrings, PCRE  the \fIovector\fP is not big enough to remember the related substrings, PCRE
1462  has to get additional memory for use during matching. Thus it is usually  has to get additional memory for use during matching. Thus it is usually
1463  advisable to supply an \fIovector\fP.  advisable to supply an \fIovector\fP.
1464  .P  .P
1465  Note that \fBpcre_info()\fP can be used to find out how many capturing  The \fBpcre_info()\fP function can be used to find out how many capturing
1466  subpatterns there are in a compiled pattern. The smallest size for  subpatterns there are in a compiled pattern. The smallest size for
1467  \fIovector\fP that will allow for \fIn\fP captured substrings, in addition to  \fIovector\fP that will allow for \fIn\fP captured substrings, in addition to
1468  the offsets of the substring matched by the whole pattern, is (\fIn\fP+1)*3.  the offsets of the substring matched by the whole pattern, is (\fIn\fP+1)*3.
1469    .P
1470    It is possible for capturing subpattern number \fIn+1\fP to match some part of
1471    the subject when subpattern \fIn\fP has not been used at all. For example, if
1472    the string "abc" is matched against the pattern (a|(z))(bc) the return from the
1473    function is 4, and subpatterns 1 and 3 are matched, but 2 is not. When this
1474    happens, both values in the offset pairs corresponding to unused subpatterns
1475    are set to -1.
1476    .P
1477    Offset values that correspond to unused subpatterns at the end of the
1478    expression are also set to -1. For example, if the string "abc" is matched
1479    against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not matched. The
1480    return from the function is 2, because the highest used capturing subpattern
1481    number is 1. However, you can refer to the offsets for the second and third
1482    capturing subpatterns if you wish (assuming the vector is large enough, of
1483    course).
1484    .P
1485    Some convenience functions are provided for extracting the captured substrings
1486    as separate strings. These are described below.
1487  .  .
1488  .\" HTML <a name="errorlist"></a>  .\" HTML <a name="errorlist"></a>
1489  .SS "Return values from \fBpcre_exec()\fP"  .SS "Error return values from \fBpcre_exec()\fP"
1490  .rs  .rs
1491  .sp  .sp
1492  If \fBpcre_exec()\fP fails, it returns a negative number. The following are  If \fBpcre_exec()\fP fails, it returns a negative number. The following are
# Line 1256  compiled in an environment of one endian Line 1513  compiled in an environment of one endian
1513  other endianness. This is the error that PCRE gives when the magic number is  other endianness. This is the error that PCRE gives when the magic number is
1514  not present.  not present.
1515  .sp  .sp
1516    PCRE_ERROR_UNKNOWN_NODE   (-5)    PCRE_ERROR_UNKNOWN_OPCODE (-5)
1517  .sp  .sp
1518  While running the pattern match, an unknown item was encountered in the  While running the pattern match, an unknown item was encountered in the
1519  compiled pattern. This error could be caused by a bug in PCRE or by overwriting  compiled pattern. This error could be caused by a bug in PCRE or by overwriting
# Line 1282  The backtracking limit, as specified by Line 1539  The backtracking limit, as specified by
1539  \fBpcre_extra\fP structure (or defaulted) was reached. See the description  \fBpcre_extra\fP structure (or defaulted) was reached. See the description
1540  above.  above.
1541  .sp  .sp
   PCRE_ERROR_RECURSIONLIMIT (-21)  
 .sp  
 The internal recursion limit, as specified by the \fImatch_limit_recursion\fP  
 field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the  
 description above.  
 .sp  
1542    PCRE_ERROR_CALLOUT        (-9)    PCRE_ERROR_CALLOUT        (-9)
1543  .sp  .sp
1544  This error is never generated by \fBpcre_exec()\fP itself. It is provided for  This error is never generated by \fBpcre_exec()\fP itself. It is provided for
# Line 1331  in PCRE or by overwriting of the compile Line 1582  in PCRE or by overwriting of the compile
1582    PCRE_ERROR_BADCOUNT       (-15)    PCRE_ERROR_BADCOUNT       (-15)
1583  .sp  .sp
1584  This error is given if the value of the \fIovecsize\fP argument is negative.  This error is given if the value of the \fIovecsize\fP argument is negative.
1585    .sp
1586      PCRE_ERROR_RECURSIONLIMIT (-21)
1587    .sp
1588    The internal recursion limit, as specified by the \fImatch_limit_recursion\fP
1589    field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the
1590    description above.
1591    .sp
1592      PCRE_ERROR_BADNEWLINE     (-23)
1593    .sp
1594    An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
1595    .P
1596    Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
1597  .  .
1598  .  .
1599  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 1342  This error is given if the value of the Line 1605  This error is given if the value of the
1605  .ti +5n  .ti +5n
1606  .B int \fIbuffersize\fP);  .B int \fIbuffersize\fP);
1607  .PP  .PP
 .br  
1608  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,
1609  .ti +5n  .ti +5n
1610  .B int \fIstringcount\fP, int \fIstringnumber\fP,  .B int \fIstringcount\fP, int \fIstringnumber\fP,
1611  .ti +5n  .ti +5n
1612  .B const char **\fIstringptr\fP);  .B const char **\fIstringptr\fP);
1613  .PP  .PP
 .br  
1614  .B int pcre_get_substring_list(const char *\fIsubject\fP,  .B int pcre_get_substring_list(const char *\fIsubject\fP,
1615  .ti +5n  .ti +5n
1616  .B int *\fIovector\fP, int \fIstringcount\fP, "const char ***\fIlistptr\fP);"  .B int *\fIovector\fP, int \fIstringcount\fP, "const char ***\fIlistptr\fP);"
# Line 1360  Captured substrings can be accessed dire Line 1621  Captured substrings can be accessed dire
1621  \fBpcre_get_substring_list()\fP are provided for extracting captured substrings  \fBpcre_get_substring_list()\fP are provided for extracting captured substrings
1622  as new, separate, zero-terminated strings. These functions identify substrings  as new, separate, zero-terminated strings. These functions identify substrings
1623  by number. The next section describes functions for extracting named  by number. The next section describes functions for extracting named
1624  substrings. A substring that contains a binary zero is correctly extracted and  substrings.
1625  has a further zero added on the end, but the result is not, of course,  .P
1626  a C string.  A substring that contains a binary zero is correctly extracted and has a
1627    further zero added on the end, but the result is not, of course, a C string.
1628    However, you can process such a string by referring to the length that is
1629    returned by \fBpcre_copy_substring()\fP and \fBpcre_get_substring()\fP.
1630    Unfortunately, the interface to \fBpcre_get_substring_list()\fP is not adequate
1631    for handling strings containing binary zeros, because the end of the final
1632    string is not independently indicated.
1633  .P  .P
1634  The first three arguments are the same for all three of these functions:  The first three arguments are the same for all three of these functions:
1635  \fIsubject\fP is the subject string that has just been successfully matched,  \fIsubject\fP is the subject string that has just been successfully matched,
# Line 1382  the string is placed in \fIbuffer\fP, wh Line 1649  the string is placed in \fIbuffer\fP, wh
1649  \fIbuffersize\fP, while for \fBpcre_get_substring()\fP a new block of memory is  \fIbuffersize\fP, while for \fBpcre_get_substring()\fP a new block of memory is
1650  obtained via \fBpcre_malloc\fP, and its address is returned via  obtained via \fBpcre_malloc\fP, and its address is returned via
1651  \fIstringptr\fP. The yield of the function is the length of the string, not  \fIstringptr\fP. The yield of the function is the length of the string, not
1652  including the terminating zero, or one of  including the terminating zero, or one of these error codes:
1653  .sp  .sp
1654    PCRE_ERROR_NOMEMORY       (-6)    PCRE_ERROR_NOMEMORY       (-6)
1655  .sp  .sp
# Line 1398  and builds a list of pointers to them. A Line 1665  and builds a list of pointers to them. A
1665  memory that is obtained via \fBpcre_malloc\fP. The address of the memory block  memory that is obtained via \fBpcre_malloc\fP. The address of the memory block
1666  is returned via \fIlistptr\fP, which is also the start of the list of string  is returned via \fIlistptr\fP, which is also the start of the list of string
1667  pointers. The end of the list is marked by a NULL pointer. The yield of the  pointers. The end of the list is marked by a NULL pointer. The yield of the
1668  function is zero if all went well, or  function is zero if all went well, or the error code
1669  .sp  .sp
1670    PCRE_ERROR_NOMEMORY       (-6)    PCRE_ERROR_NOMEMORY       (-6)
1671  .sp  .sp
# Line 1417  a previous call of \fBpcre_get_substring Line 1684  a previous call of \fBpcre_get_substring
1684  \fBpcre_get_substring_list()\fP, respectively. They do nothing more than call  \fBpcre_get_substring_list()\fP, respectively. They do nothing more than call
1685  the function pointed to by \fBpcre_free\fP, which of course could be called  the function pointed to by \fBpcre_free\fP, which of course could be called
1686  directly from a C program. However, PCRE is used in some situations where it is  directly from a C program. However, PCRE is used in some situations where it is
1687  linked via a special interface to another programming language which cannot use  linked via a special interface to another programming language that cannot use
1688  \fBpcre_free\fP directly; it is for these cases that the functions are  \fBpcre_free\fP directly; it is for these cases that the functions are
1689  provided.  provided.
1690  .  .
# Line 1429  provided. Line 1696  provided.
1696  .ti +5n  .ti +5n
1697  .B const char *\fIname\fP);  .B const char *\fIname\fP);
1698  .PP  .PP
 .br  
1699  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,
1700  .ti +5n  .ti +5n
1701  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 1438  provided. Line 1704  provided.
1704  .ti +5n  .ti +5n
1705  .B char *\fIbuffer\fP, int \fIbuffersize\fP);  .B char *\fIbuffer\fP, int \fIbuffersize\fP);
1706  .PP  .PP
 .br  
1707  .B int pcre_get_named_substring(const pcre *\fIcode\fP,  .B int pcre_get_named_substring(const pcre *\fIcode\fP,
1708  .ti +5n  .ti +5n
1709  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 1450  provided. Line 1715  provided.
1715  To extract a substring by name, you first have to find associated number.  To extract a substring by name, you first have to find associated number.
1716  For example, for this pattern  For example, for this pattern
1717  .sp  .sp
1718    (a+)b(?P<xxx>\ed+)...    (a+)b(?<xxx>\ed+)...
1719  .sp  .sp
1720  the number of the subpattern called "xxx" is 2. You can find the number from  the number of the subpattern called "xxx" is 2. If the name is known to be
1721  the name by calling \fBpcre_get_stringnumber()\fP. The first argument is the  unique (PCRE_DUPNAMES was not set), you can find the number from the name by
1722  compiled pattern, and the second is the name. The yield of the function is the  calling \fBpcre_get_stringnumber()\fP. The first argument is the compiled
1723    pattern, and the second is the name. The yield of the function is the
1724  subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no subpattern of  subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no subpattern of
1725  that name.  that name.
1726  .P  .P
# Line 1462  Given the number, you can extract the su Line 1728  Given the number, you can extract the su
1728  functions described in the previous section. For convenience, there are also  functions described in the previous section. For convenience, there are also
1729  two functions that do the whole job.  two functions that do the whole job.
1730  .P  .P
1731  Most of the arguments of \fIpcre_copy_named_substring()\fP and  Most of the arguments of \fBpcre_copy_named_substring()\fP and
1732  \fIpcre_get_named_substring()\fP are the same as those for the similarly named  \fBpcre_get_named_substring()\fP are the same as those for the similarly named
1733  functions that extract by number. As these are described in the previous  functions that extract by number. As these are described in the previous
1734  section, they are not re-described here. There are just two differences:  section, they are not re-described here. There are just two differences:
1735  .P  .P
# Line 1473  pattern. This is needed in order to gain Line 1739  pattern. This is needed in order to gain
1739  translation table.  translation table.
1740  .P  .P
1741  These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they  These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they
1742  then call \fIpcre_copy_substring()\fP or \fIpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1743  appropriate.  appropriate. \fBNOTE:\fP If PCRE_DUPNAMES is set and there are duplicate names,
1744    the behaviour may not be what you want (see the next section).
1745    .P
1746    \fBWarning:\fP If the pattern uses the "(?|" feature to set up multiple
1747    subpatterns with the same number, you cannot use names to distinguish them,
1748    because names are not included in the compiled code. The matching process uses
1749    only numbers.
1750    .
1751    .SH "DUPLICATE SUBPATTERN NAMES"
1752    .rs
1753    .sp
1754    .B int pcre_get_stringtable_entries(const pcre *\fIcode\fP,
1755    .ti +5n
1756    .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
1757    .PP
1758    When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns
1759    are not required to be unique. Normally, patterns with duplicate names are such
1760    that in any one match, only one of the named subpatterns participates. An
1761    example is shown in the
1762    .\" HREF
1763    \fBpcrepattern\fP
1764    .\"
1765    documentation.
1766    .P
1767    When duplicates are present, \fBpcre_copy_named_substring()\fP and
1768    \fBpcre_get_named_substring()\fP return the first substring corresponding to
1769    the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is
1770    returned; no data is returned. The \fBpcre_get_stringnumber()\fP function
1771    returns one of the numbers that are associated with the name, but it is not
1772    defined which it is.
1773    .P
1774    If you want to get full details of all captured substrings for a given name,
1775    you must use the \fBpcre_get_stringtable_entries()\fP function. The first
1776    argument is the compiled pattern, and the second is the name. The third and
1777    fourth are pointers to variables which are updated by the function. After it
1778    has run, they point to the first and last entries in the name-to-number table
1779    for the given name. The function itself returns the length of each entry, or
1780    PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is
1781    described above in the section entitled \fIInformation about a pattern\fP.
1782    Given all the relevant entries for the name, you can extract each of their
1783    numbers, and hence the captured data, if any.
1784  .  .
1785  .  .
1786  .SH "FINDING ALL POSSIBLE MATCHES"  .SH "FINDING ALL POSSIBLE MATCHES"
# Line 1512  will yield PCRE_ERROR_NOMATCH. Line 1818  will yield PCRE_ERROR_NOMATCH.
1818  .B int *\fIworkspace\fP, int \fIwscount\fP);  .B int *\fIworkspace\fP, int \fIwscount\fP);
1819  .P  .P
1820  The function \fBpcre_dfa_exec()\fP is called to match a subject string against  The function \fBpcre_dfa_exec()\fP is called to match a subject string against
1821  a compiled pattern, using a "DFA" matching algorithm. This has different  a compiled pattern, using a matching algorithm that scans the subject string
1822  characteristics to the normal algorithm, and is not compatible with Perl. Some  just once, and does not backtrack. This has different characteristics to the
1823  of the features of PCRE patterns are not supported. Nevertheless, there are  normal algorithm, and is not compatible with Perl. Some of the features of PCRE
1824  times when this kind of matching can be useful. For a discussion of the two  patterns are not supported. Nevertheless, there are times when this kind of
1825  matching algorithms, see the  matching can be useful. For a discussion of the two matching algorithms, see
1826    the
1827  .\" HREF  .\" HREF
1828  \fBpcrematching\fP  \fBpcrematching\fP
1829  .\"  .\"
# Line 1531  here. Line 1838  here.
1838  The two additional arguments provide workspace for the function. The workspace  The two additional arguments provide workspace for the function. The workspace
1839  vector should contain at least 20 elements. It is used for keeping track of  vector should contain at least 20 elements. It is used for keeping track of
1840  multiple paths through the pattern tree. More workspace will be needed for  multiple paths through the pattern tree. More workspace will be needed for
1841  patterns and subjects where there are a lot of possible matches.  patterns and subjects where there are a lot of potential matches.
1842  .P  .P
1843  Here is an example of a simple call to \fBpcre_dfa_exec()\fP:  Here is an example of a simple call to \fBpcre_dfa_exec()\fP:
1844  .sp  .sp
# Line 1554  Here is an example of a simple call to \ Line 1861  Here is an example of a simple call to \
1861  .rs  .rs
1862  .sp  .sp
1863  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
1864  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NOTBOL,  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,
1865  PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL,
1866  PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last three of these are  PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last three of these are
1867  the same as for \fBpcre_exec()\fP, so their description is not repeated here.  the same as for \fBpcre_exec()\fP, so their description is not repeated here.
1868  .sp  .sp
# Line 1572  matching string. Line 1879  matching string.
1879    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
1880  .sp  .sp
1881  Setting the PCRE_DFA_SHORTEST option causes the matching algorithm to stop as  Setting the PCRE_DFA_SHORTEST option causes the matching algorithm to stop as
1882  soon as it has found one match. Because of the way the DFA algorithm works,  soon as it has found one match. Because of the way the alternative algorithm
1883  this is necessarily the shortest possible match at the first possible matching  works, this is necessarily the shortest possible match at the first possible
1884  point in the subject string.  matching point in the subject string.
1885  .sp  .sp
1886    PCRE_DFA_RESTART    PCRE_DFA_RESTART
1887  .sp  .sp
# Line 1613  the three matched strings are Line 1920  the three matched strings are
1920  On success, the yield of the function is a number greater than zero, which is  On success, the yield of the function is a number greater than zero, which is
1921  the number of matched substrings. The substrings themselves are returned in  the number of matched substrings. The substrings themselves are returned in
1922  \fIovector\fP. Each string uses two elements; the first is the offset to the  \fIovector\fP. Each string uses two elements; the first is the offset to the
1923  start, and the second is the offset to the end. All the strings have the same  start, and the second is the offset to the end. In fact, all the strings have
1924  start offset. (Space could have been saved by giving this only once, but it was  the same start offset. (Space could have been saved by giving this only once,
1925  decided to retain some compatibility with the way \fBpcre_exec()\fP returns  but it was decided to retain some compatibility with the way \fBpcre_exec()\fP
1926  data, even though the meaning of the strings is different.)  returns data, even though the meaning of the strings is different.)
1927  .P  .P
1928  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
1929  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
# Line 1643  that it does not support, for instance, Line 1950  that it does not support, for instance,
1950  .sp  .sp
1951    PCRE_ERROR_DFA_UCOND      (-17)    PCRE_ERROR_DFA_UCOND      (-17)
1952  .sp  .sp
1953  This return is given if \fBpcre_dfa_exec()\fP encounters a condition item in a  This return is given if \fBpcre_dfa_exec()\fP encounters a condition item that
1954  pattern that uses a back reference for the condition. This is not supported.  uses a back reference for the condition, or a test for recursion in a specific
1955    group. These are not supported.
1956  .sp  .sp
1957    PCRE_ERROR_DFA_UMLIMIT    (-18)    PCRE_ERROR_DFA_UMLIMIT    (-18)
1958  .sp  .sp
# Line 1663  When a recursive subpattern is processed Line 1971  When a recursive subpattern is processed
1971  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This
1972  error is given if the output vector is not large enough. This should be  error is given if the output vector is not large enough. This should be
1973  extremely rare, as a vector of size 1000 is used.  extremely rare, as a vector of size 1000 is used.
1974  .P  .
1975  .in 0  .
1976  Last updated: 18 January 2006  .SH "SEE ALSO"
1977  .br  .rs
1978  Copyright (c) 1997-2006 University of Cambridge.  .sp
1979    \fBpcrebuild\fP(3), \fBpcrecallout\fP(3), \fBpcrecpp(3)\fP(3),
1980    \fBpcrematching\fP(3), \fBpcrepartial\fP(3), \fBpcreposix\fP(3),
1981    \fBpcreprecompile\fP(3), \fBpcresample\fP(3), \fBpcrestack\fP(3).
1982    .
1983    .
1984    .SH AUTHOR
1985    .rs
1986    .sp
1987    .nf
1988    Philip Hazel
1989    University Computing Service
1990    Cambridge CB2 3QH, England.
1991    .fi
1992    .
1993    .
1994    .SH REVISION
1995    .rs
1996    .sp
1997    .nf
1998    Last updated: 17 March 2009
1999    Copyright (c) 1997-2009 University of Cambridge.
2000    .fi

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