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revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC revision 569 by ph10, Sun Nov 7 16:14:50 2010 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 152  an application that uses PCRE. The heade Line 132  an application that uses PCRE. The heade
132  and PCRE_MINOR to contain the major and minor release numbers for the library.  and PCRE_MINOR to contain the major and minor release numbers for the library.
133  Applications can use these to include support for different releases of PCRE.  Applications can use these to include support for different releases of PCRE.
134  .P  .P
135    In a Windows environment, if you want to statically link an application program
136    against a non-dll \fBpcre.a\fP file, you must define PCRE_STATIC before
137    including \fBpcre.h\fP or \fBpcrecpp.h\fP, because otherwise the
138    \fBpcre_malloc()\fP and \fBpcre_free()\fP exported functions will be declared
139    \fB__declspec(dllimport)\fP, with unwanted results.
140    .P
141  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,  The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,
142  and \fBpcre_exec()\fP are used for compiling and matching regular expressions  and \fBpcre_exec()\fP are used for compiling and matching regular expressions
143  in a Perl-compatible manner. A sample program that demonstrates the simplest  in a Perl-compatible manner. A sample program that demonstrates the simplest
144  way of using them is provided in the file called \fIpcredemo.c\fP in the source  way of using them is provided in the file called \fIpcredemo.c\fP in the PCRE
145  distribution. The  source distribution. A listing of this program is given in the
146    .\" HREF
147    \fBpcredemo\fP
148    .\"
149    documentation, and the
150  .\" HREF  .\" HREF
151  \fBpcresample\fP  \fBpcresample\fP
152  .\"  .\"
153  documentation describes how to run it.  documentation describes how to compile and run it.
154  .P  .P
155  A second matching function, \fBpcre_dfa_exec()\fP, which is not  A second matching function, \fBpcre_dfa_exec()\fP, which is not
156  Perl-compatible, is also provided. This uses a different algorithm for the  Perl-compatible, is also provided. This uses a different algorithm for the
157  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
158  subject), not just one. However, this algorithm does not return captured  point in the subject), and scans the subject just once (unless there are
159    lookbehind assertions). However, this algorithm does not return captured
160  substrings. A description of the two matching algorithms and their advantages  substrings. A description of the two matching algorithms and their advantages
161  and disadvantages is given in the  and disadvantages is given in the
162  .\" HREF  .\" HREF
# Line 183  matched by \fBpcre_exec()\fP. They are: Line 174  matched by \fBpcre_exec()\fP. They are:
174    \fBpcre_get_named_substring()\fP    \fBpcre_get_named_substring()\fP
175    \fBpcre_get_substring_list()\fP    \fBpcre_get_substring_list()\fP
176    \fBpcre_get_stringnumber()\fP    \fBpcre_get_stringnumber()\fP
177      \fBpcre_get_stringtable_entries()\fP
178  .sp  .sp
179  \fBpcre_free_substring()\fP and \fBpcre_free_substring_list()\fP are also  \fBpcre_free_substring()\fP and \fBpcre_free_substring_list()\fP are also
180  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 204  should be done before calling any PCRE f
204  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
205  indirections to memory management functions. These special functions are used  indirections to memory management functions. These special functions are used
206  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
207  recursive function calls, when running the \fBpcre_exec()\fP function. This is  recursive function calls, when running the \fBpcre_exec()\fP function. See the
208  a non-standard way of building PCRE, for use in environments that have limited  .\" HREF
209  stacks. Because of the greater use of memory management, it runs more slowly.  \fBpcrebuild\fP
210  Separate functions are provided so that special-purpose external code can be  .\"
211  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
212  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
213  the same size.  greater use of memory management, it runs more slowly. Separate functions are
214    provided so that special-purpose external code can be used for this case. When
215    used, these functions are always called in a stack-like manner (last obtained,
216    first freed), and always for memory blocks of the same size. There is a
217    discussion about PCRE's stack usage in the
218    .\" HREF
219    \fBpcrestack\fP
220    .\"
221    documentation.
222  .P  .P
223  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
224  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 229  points during a matching operation. Deta
229  documentation.  documentation.
230  .  .
231  .  .
232    .\" HTML <a name="newlines"></a>
233    .SH NEWLINES
234    .rs
235    .sp
236    PCRE supports five different conventions for indicating line breaks in
237    strings: a single CR (carriage return) character, a single LF (linefeed)
238    character, the two-character sequence CRLF, any of the three preceding, or any
239    Unicode newline sequence. The Unicode newline sequences are the three just
240    mentioned, plus the single characters VT (vertical tab, U+000B), FF (formfeed,
241    U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
242    (paragraph separator, U+2029).
243    .P
244    Each of the first three conventions is used by at least one operating system as
245    its standard newline sequence. When PCRE is built, a default can be specified.
246    The default default is LF, which is the Unix standard. When PCRE is run, the
247    default can be overridden, either when a pattern is compiled, or when it is
248    matched.
249    .P
250    At compile time, the newline convention can be specified by the \fIoptions\fP
251    argument of \fBpcre_compile()\fP, or it can be specified by special text at the
252    start of the pattern itself; this overrides any other settings. See the
253    .\" HREF
254    \fBpcrepattern\fP
255    .\"
256    page for details of the special character sequences.
257    .P
258    In the PCRE documentation the word "newline" is used to mean "the character or
259    pair of characters that indicate a line break". The choice of newline
260    convention affects the handling of the dot, circumflex, and dollar
261    metacharacters, the handling of #-comments in /x mode, and, when CRLF is a
262    recognized line ending sequence, the match position advancement for a
263    non-anchored pattern. There is more detail about this in the
264    .\" HTML <a href="#execoptions">
265    .\" </a>
266    section on \fBpcre_exec()\fP options
267    .\"
268    below.
269    .P
270    The choice of newline convention does not affect the interpretation of
271    the \en or \er escape sequences, nor does it affect what \eR matches, which is
272    controlled in a similar way, but by separate options.
273    .
274    .
275  .SH MULTITHREADING  .SH MULTITHREADING
276  .rs  .rs
277  .sp  .sp
# Line 250  which it was compiled. Details are given Line 293  which it was compiled. Details are given
293  .\" HREF  .\" HREF
294  \fBpcreprecompile\fP  \fBpcreprecompile\fP
295  .\"  .\"
296  documentation.  documentation. However, compiling a regular expression with one version of PCRE
297    for use with a different version is not guaranteed to work and may cause
298    crashes.
299  .  .
300  .  .
301  .SH "CHECKING BUILD-TIME OPTIONS"  .SH "CHECKING BUILD-TIME OPTIONS"
# Line 281  properties is available; otherwise it is Line 326  properties is available; otherwise it is
326  .sp  .sp
327    PCRE_CONFIG_NEWLINE    PCRE_CONFIG_NEWLINE
328  .sp  .sp
329  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
330  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
331  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.
332    Though they are derived from ASCII, the same values are returned in EBCDIC
333    environments. The default should normally correspond to the standard sequence
334    for your operating system.
335    .sp
336      PCRE_CONFIG_BSR
337    .sp
338    The output is an integer whose value indicates what character sequences the \eR
339    escape sequence matches by default. A value of 0 means that \eR matches any
340    Unicode line ending sequence; a value of 1 means that \eR matches only CR, LF,
341    or CRLF. The default can be overridden when a pattern is compiled or matched.
342  .sp  .sp
343    PCRE_CONFIG_LINK_SIZE    PCRE_CONFIG_LINK_SIZE
344  .sp  .sp
# Line 305  documentation. Line 360  documentation.
360  .sp  .sp
361    PCRE_CONFIG_MATCH_LIMIT    PCRE_CONFIG_MATCH_LIMIT
362  .sp  .sp
363  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
364  internal matching function calls in a \fBpcre_exec()\fP execution. Further  internal matching function calls in a \fBpcre_exec()\fP execution. Further
365  details are given with \fBpcre_exec()\fP below.  details are given with \fBpcre_exec()\fP below.
366  .sp  .sp
367    PCRE_CONFIG_MATCH_LIMIT_RECURSION    PCRE_CONFIG_MATCH_LIMIT_RECURSION
368  .sp  .sp
369  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
370  recursion when calling the internal matching function in a \fBpcre_exec()\fP  recursion when calling the internal matching function in a \fBpcre_exec()\fP
371  execution. Further details are given with \fBpcre_exec()\fP below.  execution. Further details are given with \fBpcre_exec()\fP below.
372  .sp  .sp
# Line 346  avoiding the use of the stack. Line 401  avoiding the use of the stack.
401  Either of the functions \fBpcre_compile()\fP or \fBpcre_compile2()\fP can be  Either of the functions \fBpcre_compile()\fP or \fBpcre_compile2()\fP can be
402  called to compile a pattern into an internal form. The only difference between  called to compile a pattern into an internal form. The only difference between
403  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,  the two interfaces is that \fBpcre_compile2()\fP has an additional argument,
404  \fIerrorcodeptr\fP, via which a numerical error code can be returned.  \fIerrorcodeptr\fP, via which a numerical error code can be returned. To avoid
405    too much repetition, we refer just to \fBpcre_compile()\fP below, but the
406    information applies equally to \fBpcre_compile2()\fP.
407  .P  .P
408  The pattern is a C string terminated by a binary zero, and is passed in the  The pattern is a C string terminated by a binary zero, and is passed in the
409  \fIpattern\fP argument. A pointer to a single block of memory that is obtained  \fIpattern\fP argument. A pointer to a single block of memory that is obtained
410  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
411  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
412  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
413  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.
414  .P  .P
415  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
416  depend on memory location, the complete \fBpcre\fP data block is not  depend on memory location, the complete \fBpcre\fP data block is not
417  fully relocatable, because it may contain a copy of the \fItableptr\fP  fully relocatable, because it may contain a copy of the \fItableptr\fP
418  argument, which is an address (see below).  argument, which is an address (see below).
419  .P  .P
420  The \fIoptions\fP argument contains independent bits that affect the  The \fIoptions\fP argument contains various bit settings that affect the
421  compilation. It should be zero if no options are required. The available  compilation. It should be zero if no options are required. The available
422  options are described below. Some of them, in particular, those that are  options are described below. Some of them (in particular, those that are
423  compatible with Perl, can also be set and unset from within the pattern (see  compatible with Perl, but some others as well) can also be set and unset from
424  the detailed description in the  within the pattern (see the detailed description in the
425  .\" HREF  .\" HREF
426  \fBpcrepattern\fP  \fBpcrepattern\fP
427  .\"  .\"
428  documentation). For these options, the contents of the \fIoptions\fP argument  documentation). For those options that can be different in different parts of
429  specifies their initial settings at the start of compilation and execution. The  the pattern, the contents of the \fIoptions\fP argument specifies their
430  PCRE_ANCHORED option can be set at the time of matching as well as at compile  settings at the start of compilation and execution. The PCRE_ANCHORED,
431  time.  PCRE_BSR_\fIxxx\fP, and PCRE_NEWLINE_\fIxxx\fP options can be set at the time
432    of matching as well as at compile time.
433  .P  .P
434  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
435  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
436  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
437  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
438  not try to free it. The offset from the start of the pattern to the character  not try to free it. The offset from the start of the pattern to the byte that
439  where the error was discovered is placed in the variable pointed to by  was being processed when the error was discovered is placed in the variable
440  \fIerroffset\fP, which must not be NULL. If it is, an immediate error is given.  pointed to by \fIerroffset\fP, which must not be NULL. If it is, an immediate
441    error is given. Some errors are not detected until checks are carried out when
442    the whole pattern has been scanned; in this case the offset is set to the end
443    of the pattern.
444    .P
445    Note that the offset is in bytes, not characters, even in UTF-8 mode. It may
446    point into the middle of a UTF-8 character (for example, when
447    PCRE_ERROR_BADUTF8 is returned for an invalid UTF-8 string).
448  .P  .P
449  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
450  \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 426  facility, see the Line 491  facility, see the
491  .\"  .\"
492  documentation.  documentation.
493  .sp  .sp
494      PCRE_BSR_ANYCRLF
495      PCRE_BSR_UNICODE
496    .sp
497    These options (which are mutually exclusive) control what the \eR escape
498    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
499    match any Unicode newline sequence. The default is specified when PCRE is
500    built. It can be overridden from within the pattern, or by setting an option
501    when a compiled pattern is matched.
502    .sp
503    PCRE_CASELESS    PCRE_CASELESS
504  .sp  .sp
505  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 516  with UTF-8 support.
516  .sp  .sp
517  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
518  end of the subject string. Without this option, a dollar also matches  end of the subject string. Without this option, a dollar also matches
519  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
520  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.
521  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
522  a pattern.  pattern.
523  .sp  .sp
524    PCRE_DOTALL    PCRE_DOTALL
525  .sp  .sp
526  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,
527  including newlines. Without it, newlines are excluded. This option is  including those that indicate newline. Without it, a dot does not match when
528  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
529  (?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
530  character, independent of the setting of this option.  negative class such as [^a] always matches newline characters, independent of
531    the setting of this option.
532    .sp
533      PCRE_DUPNAMES
534    .sp
535    If this bit is set, names used to identify capturing subpatterns need not be
536    unique. This can be helpful for certain types of pattern when it is known that
537    only one instance of the named subpattern can ever be matched. There are more
538    details of named subpatterns below; see also the
539    .\" HREF
540    \fBpcrepattern\fP
541    .\"
542    documentation.
543  .sp  .sp
544    PCRE_EXTENDED    PCRE_EXTENDED
545  .sp  .sp
546  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
547  ignored except when escaped or inside a character class. Whitespace does not  ignored except when escaped or inside a character class. Whitespace does not
548  include the VT character (code 11). In addition, characters between an  include the VT character (code 11). In addition, characters between an
549  unescaped # outside a character class and the next newline character,  unescaped # outside a character class and the next newline, inclusive, are also
550  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
551  be changed within a pattern by a (?x) option setting.  pattern by a (?x) option setting.
552  .P  .P
553  This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
554  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 562  that is incompatible with Perl, but it i
562  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
563  special meaning causes an error, thus reserving these combinations for future  special meaning causes an error, thus reserving these combinations for future
564  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
565  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
566  controlled by this option. It can also be set by a (?X) option setting within a  give an error for this, by running it with the -w option.) There are at present
567  pattern.  no other features controlled by this option. It can also be set by a (?X)
568    option setting within a pattern.
569  .sp  .sp
570    PCRE_FIRSTLINE    PCRE_FIRSTLINE
571  .sp  .sp
572  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
573  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
574  continue over the newline.  over the newline.
575    .sp
576      PCRE_JAVASCRIPT_COMPAT
577    .sp
578    If this option is set, PCRE's behaviour is changed in some ways so that it is
579    compatible with JavaScript rather than Perl. The changes are as follows:
580    .P
581    (1) A lone closing square bracket in a pattern causes a compile-time error,
582    because this is illegal in JavaScript (by default it is treated as a data
583    character). Thus, the pattern AB]CD becomes illegal when this option is set.
584    .P
585    (2) At run time, a back reference to an unset subpattern group matches an empty
586    string (by default this causes the current matching alternative to fail). A
587    pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
588    an "a" in the subject), whereas it fails by default, for Perl compatibility.
589  .sp  .sp
590    PCRE_MULTILINE    PCRE_MULTILINE
591  .sp  .sp
# Line 496  terminating newline (unless PCRE_DOLLAR_ Line 597  terminating newline (unless PCRE_DOLLAR_
597  Perl.  Perl.
598  .P  .P
599  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
600  match immediately following or immediately before any newline in the subject  match immediately following or immediately before internal newlines in the
601  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
602  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
603  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
604  occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect.  occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect.
605  .sp  .sp
606      PCRE_NEWLINE_CR
607      PCRE_NEWLINE_LF
608      PCRE_NEWLINE_CRLF
609      PCRE_NEWLINE_ANYCRLF
610      PCRE_NEWLINE_ANY
611    .sp
612    These options override the default newline definition that was chosen when PCRE
613    was built. Setting the first or the second specifies that a newline is
614    indicated by a single character (CR or LF, respectively). Setting
615    PCRE_NEWLINE_CRLF specifies that a newline is indicated by the two-character
616    CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three
617    preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
618    that any Unicode newline sequence should be recognized. The Unicode newline
619    sequences are the three just mentioned, plus the single characters VT (vertical
620    tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line
621    separator, U+2028), and PS (paragraph separator, U+2029). The last two are
622    recognized only in UTF-8 mode.
623    .P
624    The newline setting in the options word uses three bits that are treated
625    as a number, giving eight possibilities. Currently only six are used (default
626    plus the five values above). This means that if you set more than one newline
627    option, the combination may or may not be sensible. For example,
628    PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but
629    other combinations may yield unused numbers and cause an error.
630    .P
631    The only time that a line break is specially recognized when compiling a
632    pattern is if PCRE_EXTENDED is set, and an unescaped # outside a character
633    class is encountered. This indicates a comment that lasts until after the next
634    line break sequence. In other circumstances, line break sequences are treated
635    as literal data, except that in PCRE_EXTENDED mode, both CR and LF are treated
636    as whitespace characters and are therefore ignored.
637    .P
638    The newline option that is set at compile time becomes the default that is used
639    for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.
640    .sp
641    PCRE_NO_AUTO_CAPTURE    PCRE_NO_AUTO_CAPTURE
642  .sp  .sp
643  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 510  were followed by ?: but named parenthese Line 646  were followed by ?: but named parenthese
646  they acquire numbers in the usual way). There is no equivalent of this option  they acquire numbers in the usual way). There is no equivalent of this option
647  in Perl.  in Perl.
648  .sp  .sp
649      PCRE_UCP
650    .sp
651    This option changes the way PCRE processes \eb, \ed, \es, \ew, and some of the
652    POSIX character classes. By default, only ASCII characters are recognized, but
653    if PCRE_UCP is set, Unicode properties are used instead to classify characters.
654    More details are given in the section on
655    .\" HTML <a href="pcre.html#genericchartypes">
656    .\" </a>
657    generic character types
658    .\"
659    in the
660    .\" HREF
661    \fBpcrepattern\fP
662    .\"
663    page. If you set PCRE_UCP, matching one of the items it affects takes much
664    longer. The option is available only if PCRE has been compiled with Unicode
665    property support.
666    .sp
667    PCRE_UNGREEDY    PCRE_UNGREEDY
668  .sp  .sp
669  This option inverts the "greediness" of the quantifiers so that they are not  This option inverts the "greediness" of the quantifiers so that they are not
# Line 536  page. Line 690  page.
690    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
691  .sp  .sp
692  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
693  automatically checked. If an invalid UTF-8 sequence of bytes is found,  automatically checked. There is a discussion about the
694  \fBpcre_compile()\fP returns an error. If you already know that your pattern is  .\" HTML <a href="pcre.html#utf8strings">
695  valid, and you want to skip this check for performance reasons, you can set the  .\" </a>
696  PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid  validity of UTF-8 strings
697  UTF-8 string as a pattern is undefined. It may cause your program to crash.  .\"
698  Note that this option can also be passed to \fBpcre_exec()\fP and  in the main
699  \fBpcre_dfa_exec()\fP, to suppress the UTF-8 validity checking of subject  .\" HREF
700  strings.  \fBpcre\fP
701    .\"
702    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_compile()\fP
703    returns an error. If you already know that your pattern is valid, and you want
704    to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
705    option. When it is set, the effect of passing an invalid UTF-8 string as a
706    pattern is undefined. It may cause your program to crash. Note that this option
707    can also be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress
708    the UTF-8 validity checking of subject strings.
709  .  .
710  .  .
711  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 551  strings. Line 713  strings.
713  .sp  .sp
714  The following table lists the error codes than may be returned by  The following table lists the error codes than may be returned by
715  \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
716  both compiling functions.  both compiling functions. As PCRE has developed, some error codes have fallen
717    out of use. To avoid confusion, they have not been re-used.
718  .sp  .sp
719     0  no error     0  no error
720     1  \e at end of pattern     1  \e at end of pattern
# Line 563  both compiling functions. Line 726  both compiling functions.
726     7  invalid escape sequence in character class     7  invalid escape sequence in character class
727     8  range out of order in character class     8  range out of order in character class
728     9  nothing to repeat     9  nothing to repeat
729    10  operand of unlimited repeat could match the empty string    10  [this code is not in use]
730    11  internal error: unexpected repeat    11  internal error: unexpected repeat
731    12  unrecognized character after (?    12  unrecognized character after (? or (?-
732    13  POSIX named classes are supported only within a class    13  POSIX named classes are supported only within a class
733    14  missing )    14  missing )
734    15  reference to non-existent subpattern    15  reference to non-existent subpattern
735    16  erroffset passed as NULL    16  erroffset passed as NULL
736    17  unknown option bit(s) set    17  unknown option bit(s) set
737    18  missing ) after comment    18  missing ) after comment
738    19  parentheses nested too deeply    19  [this code is not in use]
739    20  regular expression too large    20  regular expression is too large
740    21  failed to get memory    21  failed to get memory
741    22  unmatched parentheses    22  unmatched parentheses
742    23  internal error: code overflow    23  internal error: code overflow
743    24  unrecognized character after (?<    24  unrecognized character after (?<
744    25  lookbehind assertion is not fixed length    25  lookbehind assertion is not fixed length
745    26  malformed number after (?(    26  malformed number or name after (?(
746    27  conditional group contains more than two branches    27  conditional group contains more than two branches
747    28  assertion expected after (?(    28  assertion expected after (?(
748    29  (?R or (?digits must be followed by )    29  (?R or (?[+-]digits must be followed by )
749    30  unknown POSIX class name    30  unknown POSIX class name
750    31  POSIX collating elements are not supported    31  POSIX collating elements are not supported
751    32  this version of PCRE is not compiled with PCRE_UTF8 support    32  this version of PCRE is not compiled with PCRE_UTF8 support
752    33  spare error    33  [this code is not in use]
753    34  character value in \ex{...} sequence is too large    34  character value in \ex{...} sequence is too large
754    35  invalid condition (?(0)    35  invalid condition (?(0)
755    36  \eC not allowed in lookbehind assertion    36  \eC not allowed in lookbehind assertion
# Line 595  both compiling functions. Line 758  both compiling functions.
758    39  closing ) for (?C expected    39  closing ) for (?C expected
759    40  recursive call could loop indefinitely    40  recursive call could loop indefinitely
760    41  unrecognized character after (?P    41  unrecognized character after (?P
761    42  syntax error after (?P    42  syntax error in subpattern name (missing terminator)
762    43  two named groups have the same name    43  two named subpatterns have the same name
763    44  invalid UTF-8 string    44  invalid UTF-8 string
764    45  support for \eP, \ep, and \eX has not been compiled    45  support for \eP, \ep, and \eX has not been compiled
765    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
766    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
767      48  subpattern name is too long (maximum 32 characters)
768      49  too many named subpatterns (maximum 10000)
769      50  [this code is not in use]
770      51  octal value is greater than \e377 (not in UTF-8 mode)
771      52  internal error: overran compiling workspace
772      53  internal error: previously-checked referenced subpattern
773            not found
774      54  DEFINE group contains more than one branch
775      55  repeating a DEFINE group is not allowed
776      56  inconsistent NEWLINE options
777      57  \eg is not followed by a braced, angle-bracketed, or quoted
778            name/number or by a plain number
779      58  a numbered reference must not be zero
780      59  an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT)
781      60  (*VERB) not recognized
782      61  number is too big
783      62  subpattern name expected
784      63  digit expected after (?+
785      64  ] is an invalid data character in JavaScript compatibility mode
786      65  different names for subpatterns of the same number are
787            not allowed
788      66  (*MARK) must have an argument
789      67  this version of PCRE is not compiled with PCRE_UCP support
790    .sp
791    The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
792    be used if the limits were changed when PCRE was built.
793  .  .
794  .  .
795  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
# Line 619  help speed up matching, \fBpcre_study()\ Line 808  help speed up matching, \fBpcre_study()\
808  results of the study.  results of the study.
809  .P  .P
810  The returned value from \fBpcre_study()\fP can be passed directly to  The returned value from \fBpcre_study()\fP can be passed directly to
811  \fBpcre_exec()\fP. However, a \fBpcre_extra\fP block also contains other  \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. However, a \fBpcre_extra\fP block
812  fields that can be set by the caller before the block is passed; these are  also contains other fields that can be set by the caller before the block is
813  described  passed; these are described
814  .\" HTML <a href="#extradata">  .\" HTML <a href="#extradata">
815  .\" </a>  .\" </a>
816  below  below
817  .\"  .\"
818  in the section on matching a pattern.  in the section on matching a pattern.
819  .P  .P
820  If studying the pattern does not produce any additional information  If studying the pattern does not produce any useful information,
821  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program
822  wants to pass any of the other fields to \fBpcre_exec()\fP, it must set up its  wants to pass any of the other fields to \fBpcre_exec()\fP or
823  own \fBpcre_extra\fP block.  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.
824  .P  .P
825  The second argument of \fBpcre_study()\fP contains option bits. At present, no  The second argument of \fBpcre_study()\fP contains option bits. At present, no
826  options are defined, and this argument should always be zero.  options are defined, and this argument should always be zero.
# Line 651  This is a typical call to \fBpcre_study\ Line 840  This is a typical call to \fBpcre_study\
840      0,              /* no options exist */      0,              /* no options exist */
841      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
842  .sp  .sp
843  At present, studying a pattern is useful only for non-anchored patterns that do  Studying a pattern does two things: first, a lower bound for the length of
844  not have a single fixed starting character. A bitmap of possible starting  subject string that is needed to match the pattern is computed. This does not
845  bytes is created.  mean that there are any strings of that length that match, but it does
846    guarantee that no shorter strings match. The value is used by
847    \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP to avoid wasting time by trying to
848    match strings that are shorter than the lower bound. You can find out the value
849    in a calling program via the \fBpcre_fullinfo()\fP function.
850    .P
851    Studying a pattern is also useful for non-anchored patterns that do not have a
852    single fixed starting character. A bitmap of possible starting bytes is
853    created. This speeds up finding a position in the subject at which to start
854    matching.
855    .P
856    The two optimizations just described can be disabled by setting the
857    PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or
858    \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains
859    callouts, or make use of (*MARK), and you make use of these in cases where
860    matching fails. See the discussion of PCRE_NO_START_OPTIMIZE
861    .\" HTML <a href="#execoptions">
862    .\" </a>
863    below.
864    .\"
865  .  .
866  .  .
867  .\" HTML <a name="localesupport"></a>  .\" HTML <a name="localesupport"></a>
868  .SH "LOCALE SUPPORT"  .SH "LOCALE SUPPORT"
869  .rs  .rs
870  .sp  .sp
871  PCRE handles caseless matching, and determines whether characters are letters  PCRE handles caseless matching, and determines whether characters are letters,
872  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
873  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
874  less than 128. Higher-valued codes never match escapes such as \ew or \ed, but  less than 128. By default, higher-valued codes never match escapes such as \ew
875  can be tested with \ep if PCRE is built with Unicode character property  or \ed, but they can be tested with \ep if PCRE is built with Unicode character
876  support. The use of locales with Unicode is discouraged.  property support. Alternatively, the PCRE_UCP option can be set at compile
877  .P  time; this causes \ew and friends to use Unicode property support instead of
878  An internal set of tables is created in the default C locale when PCRE is  built-in tables. The use of locales with Unicode is discouraged. If you are
879  built. This is used when the final argument of \fBpcre_compile()\fP is NULL,  handling characters with codes greater than 128, you should either use UTF-8
880  and is sufficient for many applications. An alternative set of tables can,  and Unicode, or use locales, but not try to mix the two.
881  however, be supplied. These may be created in a different locale from the  .P
882  default. As more and more applications change to using Unicode, the need for  PCRE contains an internal set of tables that are used when the final argument
883  this locale support is expected to die away.  of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.
884    Normally, the internal tables recognize only ASCII characters. However, when
885    PCRE is built, it is possible to cause the internal tables to be rebuilt in the
886    default "C" locale of the local system, which may cause them to be different.
887    .P
888    The internal tables can always be overridden by tables supplied by the
889    application that calls PCRE. These may be created in a different locale from
890    the default. As more and more applications change to using Unicode, the need
891    for this locale support is expected to die away.
892  .P  .P
893  External tables are built by calling the \fBpcre_maketables()\fP function,  External tables are built by calling the \fBpcre_maketables()\fP function,
894  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 901  the following code could be used:
901    tables = pcre_maketables();    tables = pcre_maketables();
902    re = pcre_compile(..., tables);    re = pcre_compile(..., tables);
903  .sp  .sp
904    The locale name "fr_FR" is used on Linux and other Unix-like systems; if you
905    are using Windows, the name for the French locale is "french".
906    .P
907  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
908  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
909  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 950  check against passing an arbitrary memor
950  \fBpcre_fullinfo()\fP, to obtain the length of the compiled pattern:  \fBpcre_fullinfo()\fP, to obtain the length of the compiled pattern:
951  .sp  .sp
952    int rc;    int rc;
953    unsigned long int length;    size_t length;
954    rc = pcre_fullinfo(    rc = pcre_fullinfo(
955      re,               /* result of pcre_compile() */      re,               /* result of pcre_compile() */
956      pe,               /* result of pcre_study(), or NULL */      pe,               /* result of pcre_study(), or NULL */
# Line 763  a NULL table pointer. Line 982  a NULL table pointer.
982    PCRE_INFO_FIRSTBYTE    PCRE_INFO_FIRSTBYTE
983  .sp  .sp
984  Return information about the first byte of any matched string, for a  Return information about the first byte of any matched string, for a
985  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
986  old name is still recognized for backwards compatibility.)  variable. (This option used to be called PCRE_INFO_FIRSTCHAR; the old name is
987    still recognized for backwards compatibility.)
988  .P  .P
989  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
990  (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  
991  .sp  .sp
992  (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
993  starts with "^", or  starts with "^", or
# Line 787  table indicating a fixed set of bytes fo Line 1006  table indicating a fixed set of bytes fo
1006  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
1007  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
1008  .sp  .sp
1009      PCRE_INFO_HASCRORLF
1010    .sp
1011    Return 1 if the pattern contains any explicit matches for CR or LF characters,
1012    otherwise 0. The fourth argument should point to an \fBint\fP variable. An
1013    explicit match is either a literal CR or LF character, or \er or \en.
1014    .sp
1015      PCRE_INFO_JCHANGED
1016    .sp
1017    Return 1 if the (?J) or (?-J) option setting is used in the pattern, otherwise
1018    0. The fourth argument should point to an \fBint\fP variable. (?J) and
1019    (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
1020    .sp
1021    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
1022  .sp  .sp
1023  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 797  follows something of variable length. Fo Line 1028  follows something of variable length. Fo
1028  /^a\ed+z\ed+/ the returned value is "z", but for /^a\edz\ed/ the returned value  /^a\ed+z\ed+/ the returned value is "z", but for /^a\edz\ed/ the returned value
1029  is -1.  is -1.
1030  .sp  .sp
1031      PCRE_INFO_MINLENGTH
1032    .sp
1033    If the pattern was studied and a minimum length for matching subject strings
1034    was computed, its value is returned. Otherwise the returned value is -1. The
1035    value is a number of characters, not bytes (this may be relevant in UTF-8
1036    mode). The fourth argument should point to an \fBint\fP variable. A
1037    non-negative value is a lower bound to the length of any matching string. There
1038    may not be any strings of that length that do actually match, but every string
1039    that does match is at least that long.
1040    .sp
1041    PCRE_INFO_NAMECOUNT    PCRE_INFO_NAMECOUNT
1042    PCRE_INFO_NAMEENTRYSIZE    PCRE_INFO_NAMEENTRYSIZE
1043    PCRE_INFO_NAMETABLE    PCRE_INFO_NAMETABLE
1044  .sp  .sp
1045  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
1046  names are just an additional way of identifying the parentheses, which still  names are just an additional way of identifying the parentheses, which still
1047  acquire numbers. A convenience function called \fBpcre_get_named_substring()\fP  acquire numbers. Several convenience functions such as
1048  is provided for extracting an individual captured substring by name. It is also  \fBpcre_get_named_substring()\fP are provided for extracting captured
1049  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
1050  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
1051  \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,
1052  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
1053    values.
1054  .P  .P
1055  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
1056  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 816  entry; both of these return an \fBint\fP Line 1058  entry; both of these return an \fBint\fP
1058  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first
1059  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
1060  are the number of the capturing parenthesis, most significant byte first. The  are the number of the capturing parenthesis, most significant byte first. The
1061  rest of the entry is the corresponding name, zero terminated. The names are in  rest of the entry is the corresponding name, zero terminated.
1062  alphabetical order. For example, consider the following pattern (assume  .P
1063  PCRE_EXTENDED is set, so white space - including newlines - is ignored):  The names are in alphabetical order. Duplicate names may appear if (?| is used
1064    to create multiple groups with the same number, as described in the
1065    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1066    .\" </a>
1067    section on duplicate subpattern numbers
1068    .\"
1069    in the
1070    .\" HREF
1071    \fBpcrepattern\fP
1072    .\"
1073    page. Duplicate names for subpatterns with different numbers are permitted only
1074    if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the
1075    table in the order in which they were found in the pattern. In the absence of
1076    (?| this is the order of increasing number; when (?| is used this is not
1077    necessarily the case because later subpatterns may have lower numbers.
1078    .P
1079    As a simple example of the name/number table, consider the following pattern
1080    (assume PCRE_EXTENDED is set, so white space - including newlines - is
1081    ignored):
1082  .sp  .sp
1083  .\" JOIN  .\" JOIN
1084    (?P<date> (?P<year>(\ed\ed)?\ed\ed) -    (?<date> (?<year>(\ed\ed)?\ed\ed) -
1085    (?P<month>\ed\ed) - (?P<day>\ed\ed) )    (?<month>\ed\ed) - (?<day>\ed\ed) )
1086  .sp  .sp
1087  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
1088  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 1094  bytes shows in hexadecimal, and undefine
1094    00 02 y  e  a  r  00 ??    00 02 y  e  a  r  00 ??
1095  .sp  .sp
1096  When writing code to extract data from named subpatterns using the  When writing code to extract data from named subpatterns using the
1097  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
1098  different for each compiled pattern.  different for each compiled pattern.
1099  .sp  .sp
1100      PCRE_INFO_OKPARTIAL
1101    .sp
1102    Return 1 if the pattern can be used for partial matching with
1103    \fBpcre_exec()\fP, otherwise 0. The fourth argument should point to an
1104    \fBint\fP variable. From release 8.00, this always returns 1, because the
1105    restrictions that previously applied to partial matching have been lifted. The
1106    .\" HREF
1107    \fBpcrepartial\fP
1108    .\"
1109    documentation gives details of partial matching.
1110    .sp
1111    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1112  .sp  .sp
1113  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
1114  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
1115  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
1116  top-level option settings within the pattern itself.  top-level option settings at the start of the pattern itself. In other words,
1117    they are the options that will be in force when matching starts. For example,
1118    if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the
1119    result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED.
1120  .P  .P
1121  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
1122  alternatives begin with one of the following:  alternatives begin with one of the following:
# Line 869  variable. Line 1143  variable.
1143  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
1144  a \fBpcre_extra\fP block. That is, it is the value that was passed to  a \fBpcre_extra\fP block. That is, it is the value that was passed to
1145  \fBpcre_malloc()\fP when PCRE was getting memory into which to place the data  \fBpcre_malloc()\fP when PCRE was getting memory into which to place the data
1146  created by \fBpcre_study()\fP. The fourth argument should point to a  created by \fBpcre_study()\fP. If \fBpcre_extra\fP is NULL, or there is no
1147    study data, zero is returned. The fourth argument should point to a
1148  \fBsize_t\fP variable.  \fBsize_t\fP variable.
1149  .  .
1150  .  .
# Line 931  is different. (This seems a highly unlik Line 1206  is different. (This seems a highly unlik
1206  .P  .P
1207  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
1208  compiled pattern, which is passed in the \fIcode\fP argument. If the  compiled pattern, which is passed in the \fIcode\fP argument. If the
1209  pattern has been studied, the result of the study should be passed in the  pattern was studied, the result of the study should be passed in the
1210  \fIextra\fP argument. This function is the main matching facility of the  \fIextra\fP argument. This function is the main matching facility of the
1211  library, and it operates in a Perl-like manner. For specialist use there is  library, and it operates in a Perl-like manner. For specialist use there is
1212  also an alternative matching function, which is described  also an alternative matching function, which is described
# Line 981  fields (not necessarily in this order): Line 1256  fields (not necessarily in this order):
1256    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1257    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1258    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1259      unsigned char **\fImark\fP;
1260  .sp  .sp
1261  The \fIflags\fP field is a bitmap that specifies which of the other fields  The \fIflags\fP field is a bitmap that specifies which of the other fields
1262  are set. The flag bits are:  are set. The flag bits are:
# Line 990  are set. The flag bits are: Line 1266  are set. The flag bits are:
1266    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1267    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1268    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1269      PCRE_EXTRA_MARK
1270  .sp  .sp
1271  Other flag bits should be set to zero. The \fIstudy_data\fP field is set in the  Other flag bits should be set to zero. The \fIstudy_data\fP field is set in the
1272  \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with  \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with
# Line 999  the block by setting the other fields an Line 1276  the block by setting the other fields an
1276  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
1277  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,
1278  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
1279  classic example is the use of nested unlimited repeats.  classic example is a pattern that uses nested unlimited repeats.
1280  .P  .P
1281  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly
1282  (sometimes recursively). The limit set by \fImatch_limit\fP is imposed on the  (sometimes recursively). The limit set by \fImatch_limit\fP is imposed on the
# Line 1032  with a \fBpcre_extra\fP block in which \ Line 1309  with a \fBpcre_extra\fP block in which \
1309  PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the \fIflags\fP field. If the limit  PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the \fIflags\fP field. If the limit
1310  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.
1311  .P  .P
1312  The \fIpcre_callout\fP field is used in conjunction with the "callout" feature,  The \fIcallout_data\fP field is used in conjunction with the "callout" feature,
1313  which is described in the  and is described in the
1314  .\" HREF  .\" HREF
1315  \fBpcrecallout\fP  \fBpcrecallout\fP
1316  .\"  .\"
# Line 1052  called. See the Line 1329  called. See the
1329  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1330  .\"  .\"
1331  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1332    .P
1333    If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must
1334    be set to point to a \fBchar *\fP variable. If the pattern contains any
1335    backtracking control verbs such as (*MARK:NAME), and the execution ends up with
1336    a name to pass back, a pointer to the name string (zero terminated) is placed
1337    in the variable pointed to by the \fImark\fP field. The names are within the
1338    compiled pattern; if you wish to retain such a name you must copy it before
1339    freeing the memory of a compiled pattern. If there is no name to pass back, the
1340    variable pointed to by the \fImark\fP field set to NULL. For details of the
1341    backtracking control verbs, see the section entitled
1342    .\" HTML <a href="pcrepattern#backtrackcontrol">
1343    .\" </a>
1344    "Backtracking control"
1345    .\"
1346    in the
1347    .\" HREF
1348    \fBpcrepattern\fP
1349    .\"
1350    documentation.
1351  .  .
1352    .
1353    .\" HTML <a name="execoptions"></a>
1354  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
1355  .rs  .rs
1356  .sp  .sp
1357  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
1358  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,
1359  PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1360    PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
1361    PCRE_PARTIAL_HARD.
1362  .sp  .sp
1363    PCRE_ANCHORED    PCRE_ANCHORED
1364  .sp  .sp
# Line 1067  matching position. If a pattern was comp Line 1367  matching position. If a pattern was comp
1367  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
1368  matching time.  matching time.
1369  .sp  .sp
1370      PCRE_BSR_ANYCRLF
1371      PCRE_BSR_UNICODE
1372    .sp
1373    These options (which are mutually exclusive) control what the \eR escape
1374    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1375    match any Unicode newline sequence. These options override the choice that was
1376    made or defaulted when the pattern was compiled.
1377    .sp
1378      PCRE_NEWLINE_CR
1379      PCRE_NEWLINE_LF
1380      PCRE_NEWLINE_CRLF
1381      PCRE_NEWLINE_ANYCRLF
1382      PCRE_NEWLINE_ANY
1383    .sp
1384    These options override the newline definition that was chosen or defaulted when
1385    the pattern was compiled. For details, see the description of
1386    \fBpcre_compile()\fP above. During matching, the newline choice affects the
1387    behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1388    the way the match position is advanced after a match failure for an unanchored
1389    pattern.
1390    .P
1391    When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a
1392    match attempt for an unanchored pattern fails when the current position is at a
1393    CRLF sequence, and the pattern contains no explicit matches for CR or LF
1394    characters, the match position is advanced by two characters instead of one, in
1395    other words, to after the CRLF.
1396    .P
1397    The above rule is a compromise that makes the most common cases work as
1398    expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1399    set), it does not match the string "\er\enA" because, after failing at the
1400    start, it skips both the CR and the LF before retrying. However, the pattern
1401    [\er\en]A does match that string, because it contains an explicit CR or LF
1402    reference, and so advances only by one character after the first failure.
1403    .P
1404    An explicit match for CR of LF is either a literal appearance of one of those
1405    characters, or one of the \er or \en escape sequences. Implicit matches such as
1406    [^X] do not count, nor does \es (which includes CR and LF in the characters
1407    that it matches).
1408    .P
1409    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1410    valid newline sequence and explicit \er or \en escapes appear in the pattern.
1411    .sp
1412    PCRE_NOTBOL    PCRE_NOTBOL
1413  .sp  .sp
1414  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 1091  match the empty string, the entire match Line 1433  match the empty string, the entire match
1433  .sp  .sp
1434    a?b?    a?b?
1435  .sp  .sp
1436  is applied to a string not beginning with "a" or "b", it matches the empty  is applied to a string not beginning with "a" or "b", it matches an empty
1437  string at the start of the subject. With PCRE_NOTEMPTY set, this match is not  string at the start of the subject. With PCRE_NOTEMPTY set, this match is not
1438  valid, so PCRE searches further into the string for occurrences of "a" or "b".  valid, so PCRE searches further into the string for occurrences of "a" or "b".
1439  .P  .sp
1440  Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case    PCRE_NOTEMPTY_ATSTART
1441  of a pattern match of the empty string within its \fBsplit()\fP function, and  .sp
1442  when using the /g modifier. It is possible to emulate Perl's behaviour after  This is like PCRE_NOTEMPTY, except that an empty string match that is not at
1443  matching a null string by first trying the match again at the same offset with  the start of the subject is permitted. If the pattern is anchored, such a match
1444  PCRE_NOTEMPTY and PCRE_ANCHORED, and then if that fails by advancing the  can occur only if the pattern contains \eK.
1445  starting offset (see below) and trying an ordinary match again. There is some  .P
1446  code that demonstrates how to do this in the \fIpcredemo.c\fP sample program.  Perl has no direct equivalent of PCRE_NOTEMPTY or PCRE_NOTEMPTY_ATSTART, but it
1447    does make a special case of a pattern match of the empty string within its
1448    \fBsplit()\fP function, and when using the /g modifier. It is possible to
1449    emulate Perl's behaviour after matching a null string by first trying the match
1450    again at the same offset with PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED, and then
1451    if that fails, by advancing the starting offset (see below) and trying an
1452    ordinary match again. There is some code that demonstrates how to do this in
1453    the
1454    .\" HREF
1455    \fBpcredemo\fP
1456    .\"
1457    sample program. In the most general case, you have to check to see if the
1458    newline convention recognizes CRLF as a newline, and if so, and the current
1459    character is CR followed by LF, advance the starting offset by two characters
1460    instead of one.
1461    .sp
1462      PCRE_NO_START_OPTIMIZE
1463    .sp
1464    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1465    a match, in order to speed up the process. For example, if it is known that an
1466    unanchored match must start with a specific character, it searches the subject
1467    for that character, and fails immediately if it cannot find it, without
1468    actually running the main matching function. This means that a special item
1469    such as (*COMMIT) at the start of a pattern is not considered until after a
1470    suitable starting point for the match has been found. When callouts or (*MARK)
1471    items are in use, these "start-up" optimizations can cause them to be skipped
1472    if the pattern is never actually used. The start-up optimizations are in effect
1473    a pre-scan of the subject that takes place before the pattern is run.
1474    .P
1475    The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1476    causing performance to suffer, but ensuring that in cases where the result is
1477    "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
1478    are considered at every possible starting position in the subject string.
1479    Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
1480    Consider the pattern
1481    .sp
1482      (*COMMIT)ABC
1483    .sp
1484    When this is compiled, PCRE records the fact that a match must start with the
1485    character "A". Suppose the subject string is "DEFABC". The start-up
1486    optimization scans along the subject, finds "A" and runs the first match
1487    attempt from there. The (*COMMIT) item means that the pattern must match the
1488    current starting position, which in this case, it does. However, if the same
1489    match is run with PCRE_NO_START_OPTIMIZE set, the initial scan along the
1490    subject string does not happen. The first match attempt is run starting from
1491    "D" and when this fails, (*COMMIT) prevents any further matches being tried, so
1492    the overall result is "no match". If the pattern is studied, more start-up
1493    optimizations may be used. For example, a minimum length for the subject may be
1494    recorded. Consider the pattern
1495    .sp
1496      (*MARK:A)(X|Y)
1497    .sp
1498    The minimum length for a match is one character. If the subject is "ABC", there
1499    will be attempts to match "ABC", "BC", "C", and then finally an empty string.
1500    If the pattern is studied, the final attempt does not take place, because PCRE
1501    knows that the subject is too short, and so the (*MARK) is never encountered.
1502    In this case, studying the pattern does not affect the overall match result,
1503    which is still "no match", but it does affect the auxiliary information that is
1504    returned.
1505  .sp  .sp
1506    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1507  .sp  .sp
1508  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
1509  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1510  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
1511  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
1512  \fBpcre_exec()\fP returns the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP  strings in the
1513  contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.  .\" HTML <a href="pcre.html#utf8strings">
1514    .\" </a>
1515    section on UTF-8 support
1516    .\"
1517    in the main
1518    .\" HREF
1519    \fBpcre\fP
1520    .\"
1521    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1522    the error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is
1523    a truncated UTF-8 character at the end of the subject, PCRE_ERROR_SHORTUTF8. If
1524    \fIstartoffset\fP contains a value that does not point to the start of a UTF-8
1525    character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
1526    returned.
1527  .P  .P
1528  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
1529  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
1530  calling \fBpcre_exec()\fP. You might want to do this for the second and  calling \fBpcre_exec()\fP. You might want to do this for the second and
1531  subsequent calls to \fBpcre_exec()\fP if you are making repeated calls to find  subsequent calls to \fBpcre_exec()\fP if you are making repeated calls to find
1532  all the matches in a single subject string. However, you should be sure that  all the matches in a single subject string. However, you should be sure that
1533  the value of \fIstartoffset\fP points to the start of a UTF-8 character. When  the value of \fIstartoffset\fP points to the start of a UTF-8 character (or the
1534  PCRE_NO_UTF8_CHECK is set, the effect of passing an invalid UTF-8 string as a  end of the subject). When PCRE_NO_UTF8_CHECK is set, the effect of passing an
1535  subject, or a value of \fIstartoffset\fP that does not point to the start of a  invalid UTF-8 string as a subject or an invalid value of \fIstartoffset\fP is
1536  UTF-8 character, is undefined. Your program may crash.  undefined. Your program may crash.
1537  .sp  .sp
1538    PCRE_PARTIAL    PCRE_PARTIAL_HARD
1539  .sp    PCRE_PARTIAL_SOFT
1540  This option turns on the partial matching feature. If the subject string fails  .sp
1541  to match the pattern, but at some point during the matching process the end of  These options turn on the partial matching feature. For backwards
1542  the subject was reached (that is, the subject partially matches the pattern and  compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match
1543  the failure to match occurred only because there were not enough subject  occurs if the end of the subject string is reached successfully, but there are
1544  characters), \fBpcre_exec()\fP returns PCRE_ERROR_PARTIAL instead of  not enough subject characters to complete the match. If this happens when
1545  PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is used, there are restrictions on what  PCRE_PARTIAL_SOFT (but not PCRE_PARTIAL_HARD) is set, matching continues by
1546  may appear in the pattern. These are discussed in the  testing any remaining alternatives. Only if no complete match can be found is
1547    PCRE_ERROR_PARTIAL returned instead of PCRE_ERROR_NOMATCH. In other words,
1548    PCRE_PARTIAL_SOFT says that the caller is prepared to handle a partial match,
1549    but only if no complete match can be found.
1550    .P
1551    If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a
1552    partial match is found, \fBpcre_exec()\fP immediately returns
1553    PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,
1554    when PCRE_PARTIAL_HARD is set, a partial match is considered to be more
1555    important that an alternative complete match.
1556    .P
1557    In both cases, the portion of the string that was inspected when the partial
1558    match was found is set as the first matching string. There is a more detailed
1559    discussion of partial and multi-segment matching, with examples, in the
1560  .\" HREF  .\" HREF
1561  \fBpcrepartial\fP  \fBpcrepartial\fP
1562  .\"  .\"
1563  documentation.  documentation.
1564  .  .
1565    .
1566  .SS "The string to be matched by \fBpcre_exec()\fP"  .SS "The string to be matched by \fBpcre_exec()\fP"
1567  .rs  .rs
1568  .sp  .sp
1569  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
1570  \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
1571  \fIstartoffset\fP. In UTF-8 mode, the byte offset must point to the start of a  in \fIstartoffset\fP. If this is negative or greater than the length of the
1572  UTF-8 character. Unlike the pattern string, the subject may contain binary zero  subject, \fBpcre_exec()\fP returns PCRE_ERROR_BADOFFSET.
1573  bytes. When the starting offset is zero, the search for a match starts at the  .P
1574  beginning of the subject, and this is by far the most common case.  In UTF-8 mode, the byte offset must point to the start of a UTF-8 character (or
1575    the end of the subject). Unlike the pattern string, the subject may contain
1576    binary zero bytes. When the starting offset is zero, the search for a match
1577    starts at the beginning of the subject, and this is by far the most common
1578    case.
1579  .P  .P
1580  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
1581  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 1164  start of the subject, which is deemed to Line 1595  start of the subject, which is deemed to
1595  set to 4, it finds the second occurrence of "iss" because it is able to look  set to 4, it finds the second occurrence of "iss" because it is able to look
1596  behind the starting point to discover that it is preceded by a letter.  behind the starting point to discover that it is preceded by a letter.
1597  .P  .P
1598    Finding all the matches in a subject is tricky when the pattern can match an
1599    empty string. It is possible to emulate Perl's /g behaviour by first trying the
1600    match again at the same offset, with the PCRE_NOTEMPTY_ATSTART and
1601    PCRE_ANCHORED options, and then if that fails, advancing the starting offset
1602    and trying an ordinary match again. There is some code that demonstrates how to
1603    do this in the
1604    .\" HREF
1605    \fBpcredemo\fP
1606    .\"
1607    sample program. In the most general case, you have to check to see if the
1608    newline convention recognizes CRLF as a newline, and if so, and the current
1609    character is CR followed by LF, advance the starting offset by two characters
1610    instead of one.
1611    .P
1612  If a non-zero starting offset is passed when the pattern is anchored, one  If a non-zero starting offset is passed when the pattern is anchored, one
1613  attempt to match at the given offset is made. This can only succeed if the  attempt to match at the given offset is made. This can only succeed if the
1614  pattern does not require the match to be at the start of the subject.  pattern does not require the match to be at the start of the subject.
1615  .  .
1616    .
1617  .SS "How \fBpcre_exec()\fP returns captured substrings"  .SS "How \fBpcre_exec()\fP returns captured substrings"
1618  .rs  .rs
1619  .sp  .sp
# Line 1178  pattern. Following the usage in Jeffrey Line 1624  pattern. Following the usage in Jeffrey
1624  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
1625  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1626  .P  .P
1627  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
1628  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
1629  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
1630  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1631  .P  .P
1632  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,
1633  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
1634  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1635  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1636  \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
1637  rounded down.  rounded down.
1638  .P  .P
1639  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1640  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1641  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
1642  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
1643  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
1644  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
1645  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1646  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1647  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
1648  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
1649  just the first pair of offsets has been set.  used for the first capturing subpattern, and so on. The value returned by
1650  .P  \fBpcre_exec()\fP is one more than the highest numbered pair that has been set.
1651  Some convenience functions are provided for extracting the captured substrings  For example, if two substrings have been captured, the returned value is 3. If
1652  as separate strings. These are described in the following section.  there are no capturing subpatterns, the return value from a successful match is
1653  .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.  
1654  .P  .P
1655  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
1656  string that it matched that is returned.  string that it matched that is returned.
1657  .P  .P
1658  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
1659  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
1660  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,
1661  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
1662  \fIovecsize\fP as zero. However, if the pattern contains back references and  \fIovecsize\fP as zero. However, if the pattern contains back references and
1663  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
1664  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
1665  advisable to supply an \fIovector\fP.  advisable to supply an \fIovector\fP.
1666  .P  .P
1667  Note that \fBpcre_info()\fP can be used to find out how many capturing  The \fBpcre_fullinfo()\fP function can be used to find out how many capturing
1668  subpatterns there are in a compiled pattern. The smallest size for  subpatterns there are in a compiled pattern. The smallest size for
1669  \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
1670  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.
1671    .P
1672    It is possible for capturing subpattern number \fIn+1\fP to match some part of
1673    the subject when subpattern \fIn\fP has not been used at all. For example, if
1674    the string "abc" is matched against the pattern (a|(z))(bc) the return from the
1675    function is 4, and subpatterns 1 and 3 are matched, but 2 is not. When this
1676    happens, both values in the offset pairs corresponding to unused subpatterns
1677    are set to -1.
1678    .P
1679    Offset values that correspond to unused subpatterns at the end of the
1680    expression are also set to -1. For example, if the string "abc" is matched
1681    against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not matched. The
1682    return from the function is 2, because the highest used capturing subpattern
1683    number is 1, and the offsets for for the second and third capturing subpatterns
1684    (assuming the vector is large enough, of course) are set to -1.
1685    .P
1686    \fBNote\fP: Elements of \fIovector\fP that do not correspond to capturing
1687    parentheses in the pattern are never changed. That is, if a pattern contains
1688    \fIn\fP capturing parentheses, no more than \fIovector[0]\fP to
1689    \fIovector[2n+1]\fP are set by \fBpcre_exec()\fP. The other elements retain
1690    whatever values they previously had.
1691    .P
1692    Some convenience functions are provided for extracting the captured substrings
1693    as separate strings. These are described below.
1694  .  .
1695  .\" HTML <a name="errorlist"></a>  .\" HTML <a name="errorlist"></a>
1696  .SS "Return values from \fBpcre_exec()\fP"  .SS "Error return values from \fBpcre_exec()\fP"
1697  .rs  .rs
1698  .sp  .sp
1699  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 1720  compiled in an environment of one endian
1720  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
1721  not present.  not present.
1722  .sp  .sp
1723    PCRE_ERROR_UNKNOWN_NODE   (-5)    PCRE_ERROR_UNKNOWN_OPCODE (-5)
1724  .sp  .sp
1725  While running the pattern match, an unknown item was encountered in the  While running the pattern match, an unknown item was encountered in the
1726  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 1269  If a pattern contains back references, b Line 1733  If a pattern contains back references, b
1733  gets a block of memory at the start of matching to use for this purpose. If the  gets a block of memory at the start of matching to use for this purpose. If the
1734  call via \fBpcre_malloc()\fP fails, this error is given. The memory is  call via \fBpcre_malloc()\fP fails, this error is given. The memory is
1735  automatically freed at the end of matching.  automatically freed at the end of matching.
1736    .P
1737    This error is also given if \fBpcre_stack_malloc()\fP fails in
1738    \fBpcre_exec()\fP. This can happen only when PCRE has been compiled with
1739    \fB--disable-stack-for-recursion\fP.
1740  .sp  .sp
1741    PCRE_ERROR_NOSUBSTRING    (-7)    PCRE_ERROR_NOSUBSTRING    (-7)
1742  .sp  .sp
# Line 1282  The backtracking limit, as specified by Line 1750  The backtracking limit, as specified by
1750  \fBpcre_extra\fP structure (or defaulted) was reached. See the description  \fBpcre_extra\fP structure (or defaulted) was reached. See the description
1751  above.  above.
1752  .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  
1753    PCRE_ERROR_CALLOUT        (-9)    PCRE_ERROR_CALLOUT        (-9)
1754  .sp  .sp
1755  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 1300  documentation for details. Line 1762  documentation for details.
1762    PCRE_ERROR_BADUTF8        (-10)    PCRE_ERROR_BADUTF8        (-10)
1763  .sp  .sp
1764  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.
1765    However, if PCRE_PARTIAL_HARD is set and the problem is a truncated UTF-8
1766    character at the end of the subject, PCRE_ERROR_SHORTUTF8 is used instead.
1767  .sp  .sp
1768    PCRE_ERROR_BADUTF8_OFFSET (-11)    PCRE_ERROR_BADUTF8_OFFSET (-11)
1769  .sp  .sp
1770  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 valid, but the value
1771  of \fIstartoffset\fP did not point to the beginning of a UTF-8 character.  of \fIstartoffset\fP did not point to the beginning of a UTF-8 character or the
1772    end of the subject.
1773  .sp  .sp
1774    PCRE_ERROR_PARTIAL        (-12)    PCRE_ERROR_PARTIAL        (-12)
1775  .sp  .sp
# Line 1316  documentation for details of partial mat Line 1781  documentation for details of partial mat
1781  .sp  .sp
1782    PCRE_ERROR_BADPARTIAL     (-13)    PCRE_ERROR_BADPARTIAL     (-13)
1783  .sp  .sp
1784  The PCRE_PARTIAL option was used with a compiled pattern containing items that  This code is no longer in use. It was formerly returned when the PCRE_PARTIAL
1785  are not supported for partial matching. See the  option was used with a compiled pattern containing items that were not
1786  .\" HREF  supported for partial matching. From release 8.00 onwards, there are no
1787  \fBpcrepartial\fP  restrictions on partial matching.
 .\"  
 documentation for details of partial matching.  
1788  .sp  .sp
1789    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
1790  .sp  .sp
# Line 1331  in PCRE or by overwriting of the compile Line 1794  in PCRE or by overwriting of the compile
1794    PCRE_ERROR_BADCOUNT       (-15)    PCRE_ERROR_BADCOUNT       (-15)
1795  .sp  .sp
1796  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.
1797    .sp
1798      PCRE_ERROR_RECURSIONLIMIT (-21)
1799    .sp
1800    The internal recursion limit, as specified by the \fImatch_limit_recursion\fP
1801    field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the
1802    description above.
1803    .sp
1804      PCRE_ERROR_BADNEWLINE     (-23)
1805    .sp
1806    An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
1807    .sp
1808      PCRE_ERROR_BADOFFSET      (-24)
1809    .sp
1810    The value of \fIstartoffset\fP was negative or greater than the length of the
1811    subject, that is, the value in \fIlength\fP.
1812    .sp
1813      PCRE_ERROR_SHORTUTF8      (-25)
1814    .sp
1815    The subject string ended with an incomplete (truncated) UTF-8 character, and
1816    the PCRE_PARTIAL_HARD option was set. Without this option, PCRE_ERROR_BADUTF8
1817    is returned in this situation.
1818    .P
1819    Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
1820  .  .
1821  .  .
1822  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 1342  This error is given if the value of the Line 1828  This error is given if the value of the
1828  .ti +5n  .ti +5n
1829  .B int \fIbuffersize\fP);  .B int \fIbuffersize\fP);
1830  .PP  .PP
 .br  
1831  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,
1832  .ti +5n  .ti +5n
1833  .B int \fIstringcount\fP, int \fIstringnumber\fP,  .B int \fIstringcount\fP, int \fIstringnumber\fP,
1834  .ti +5n  .ti +5n
1835  .B const char **\fIstringptr\fP);  .B const char **\fIstringptr\fP);
1836  .PP  .PP
 .br  
1837  .B int pcre_get_substring_list(const char *\fIsubject\fP,  .B int pcre_get_substring_list(const char *\fIsubject\fP,
1838  .ti +5n  .ti +5n
1839  .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 1844  Captured substrings can be accessed dire
1844  \fBpcre_get_substring_list()\fP are provided for extracting captured substrings  \fBpcre_get_substring_list()\fP are provided for extracting captured substrings
1845  as new, separate, zero-terminated strings. These functions identify substrings  as new, separate, zero-terminated strings. These functions identify substrings
1846  by number. The next section describes functions for extracting named  by number. The next section describes functions for extracting named
1847  substrings. A substring that contains a binary zero is correctly extracted and  substrings.
1848  has a further zero added on the end, but the result is not, of course,  .P
1849  a C string.  A substring that contains a binary zero is correctly extracted and has a
1850    further zero added on the end, but the result is not, of course, a C string.
1851    However, you can process such a string by referring to the length that is
1852    returned by \fBpcre_copy_substring()\fP and \fBpcre_get_substring()\fP.
1853    Unfortunately, the interface to \fBpcre_get_substring_list()\fP is not adequate
1854    for handling strings containing binary zeros, because the end of the final
1855    string is not independently indicated.
1856  .P  .P
1857  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:
1858  \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 1872  the string is placed in \fIbuffer\fP, wh
1872  \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
1873  obtained via \fBpcre_malloc\fP, and its address is returned via  obtained via \fBpcre_malloc\fP, and its address is returned via
1874  \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
1875  including the terminating zero, or one of  including the terminating zero, or one of these error codes:
1876  .sp  .sp
1877    PCRE_ERROR_NOMEMORY       (-6)    PCRE_ERROR_NOMEMORY       (-6)
1878  .sp  .sp
# Line 1398  and builds a list of pointers to them. A Line 1888  and builds a list of pointers to them. A
1888  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
1889  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
1890  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
1891  function is zero if all went well, or  function is zero if all went well, or the error code
1892  .sp  .sp
1893    PCRE_ERROR_NOMEMORY       (-6)    PCRE_ERROR_NOMEMORY       (-6)
1894  .sp  .sp
# Line 1417  a previous call of \fBpcre_get_substring Line 1907  a previous call of \fBpcre_get_substring
1907  \fBpcre_get_substring_list()\fP, respectively. They do nothing more than call  \fBpcre_get_substring_list()\fP, respectively. They do nothing more than call
1908  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
1909  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
1910  linked via a special interface to another programming language which cannot use  linked via a special interface to another programming language that cannot use
1911  \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
1912  provided.  provided.
1913  .  .
# Line 1429  provided. Line 1919  provided.
1919  .ti +5n  .ti +5n
1920  .B const char *\fIname\fP);  .B const char *\fIname\fP);
1921  .PP  .PP
 .br  
1922  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,
1923  .ti +5n  .ti +5n
1924  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 1438  provided. Line 1927  provided.
1927  .ti +5n  .ti +5n
1928  .B char *\fIbuffer\fP, int \fIbuffersize\fP);  .B char *\fIbuffer\fP, int \fIbuffersize\fP);
1929  .PP  .PP
 .br  
1930  .B int pcre_get_named_substring(const pcre *\fIcode\fP,  .B int pcre_get_named_substring(const pcre *\fIcode\fP,
1931  .ti +5n  .ti +5n
1932  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 1450  provided. Line 1938  provided.
1938  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.
1939  For example, for this pattern  For example, for this pattern
1940  .sp  .sp
1941    (a+)b(?P<xxx>\ed+)...    (a+)b(?<xxx>\ed+)...
1942  .sp  .sp
1943  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
1944  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
1945  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
1946    pattern, and the second is the name. The yield of the function is the
1947  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
1948  that name.  that name.
1949  .P  .P
# Line 1462  Given the number, you can extract the su Line 1951  Given the number, you can extract the su
1951  functions described in the previous section. For convenience, there are also  functions described in the previous section. For convenience, there are also
1952  two functions that do the whole job.  two functions that do the whole job.
1953  .P  .P
1954  Most of the arguments of \fIpcre_copy_named_substring()\fP and  Most of the arguments of \fBpcre_copy_named_substring()\fP and
1955  \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
1956  functions that extract by number. As these are described in the previous  functions that extract by number. As these are described in the previous
1957  section, they are not re-described here. There are just two differences:  section, they are not re-described here. There are just two differences:
1958  .P  .P
# Line 1473  pattern. This is needed in order to gain Line 1962  pattern. This is needed in order to gain
1962  translation table.  translation table.
1963  .P  .P
1964  These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they  These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they
1965  then call \fIpcre_copy_substring()\fP or \fIpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1966  appropriate.  appropriate. \fBNOTE:\fP If PCRE_DUPNAMES is set and there are duplicate names,
1967    the behaviour may not be what you want (see the next section).
1968    .P
1969    \fBWarning:\fP If the pattern uses the (?| feature to set up multiple
1970    subpatterns with the same number, as described in the
1971    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1972    .\" </a>
1973    section on duplicate subpattern numbers
1974    .\"
1975    in the
1976    .\" HREF
1977    \fBpcrepattern\fP
1978    .\"
1979    page, you cannot use names to distinguish the different subpatterns, because
1980    names are not included in the compiled code. The matching process uses only
1981    numbers. For this reason, the use of different names for subpatterns of the
1982    same number causes an error at compile time.
1983    .
1984    .SH "DUPLICATE SUBPATTERN NAMES"
1985    .rs
1986    .sp
1987    .B int pcre_get_stringtable_entries(const pcre *\fIcode\fP,
1988    .ti +5n
1989    .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
1990    .PP
1991    When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns
1992    are not required to be unique. (Duplicate names are always allowed for
1993    subpatterns with the same number, created by using the (?| feature. Indeed, if
1994    such subpatterns are named, they are required to use the same names.)
1995    .P
1996    Normally, patterns with duplicate names are such that in any one match, only
1997    one of the named subpatterns participates. An example is shown in the
1998    .\" HREF
1999    \fBpcrepattern\fP
2000    .\"
2001    documentation.
2002    .P
2003    When duplicates are present, \fBpcre_copy_named_substring()\fP and
2004    \fBpcre_get_named_substring()\fP return the first substring corresponding to
2005    the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is
2006    returned; no data is returned. The \fBpcre_get_stringnumber()\fP function
2007    returns one of the numbers that are associated with the name, but it is not
2008    defined which it is.
2009    .P
2010    If you want to get full details of all captured substrings for a given name,
2011    you must use the \fBpcre_get_stringtable_entries()\fP function. The first
2012    argument is the compiled pattern, and the second is the name. The third and
2013    fourth are pointers to variables which are updated by the function. After it
2014    has run, they point to the first and last entries in the name-to-number table
2015    for the given name. The function itself returns the length of each entry, or
2016    PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is
2017    described above in the section entitled \fIInformation about a pattern\fP.
2018    Given all the relevant entries for the name, you can extract each of their
2019    numbers, and hence the captured data, if any.
2020  .  .
2021  .  .
2022  .SH "FINDING ALL POSSIBLE MATCHES"  .SH "FINDING ALL POSSIBLE MATCHES"
# Line 1512  will yield PCRE_ERROR_NOMATCH. Line 2054  will yield PCRE_ERROR_NOMATCH.
2054  .B int *\fIworkspace\fP, int \fIwscount\fP);  .B int *\fIworkspace\fP, int \fIwscount\fP);
2055  .P  .P
2056  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
2057  a compiled pattern, using a "DFA" matching algorithm. This has different  a compiled pattern, using a matching algorithm that scans the subject string
2058  characteristics to the normal algorithm, and is not compatible with Perl. Some  just once, and does not backtrack. This has different characteristics to the
2059  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
2060  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
2061  matching algorithms, see the  matching can be useful. For a discussion of the two matching algorithms, and a
2062    list of features that \fBpcre_dfa_exec()\fP does not support, see the
2063  .\" HREF  .\" HREF
2064  \fBpcrematching\fP  \fBpcrematching\fP
2065  .\"  .\"
# Line 1531  here. Line 2074  here.
2074  The two additional arguments provide workspace for the function. The workspace  The two additional arguments provide workspace for the function. The workspace
2075  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
2076  multiple paths through the pattern tree. More workspace will be needed for  multiple paths through the pattern tree. More workspace will be needed for
2077  patterns and subjects where there are a lot of possible matches.  patterns and subjects where there are a lot of potential matches.
2078  .P  .P
2079  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:
2080  .sp  .sp
# Line 1554  Here is an example of a simple call to \ Line 2097  Here is an example of a simple call to \
2097  .rs  .rs
2098  .sp  .sp
2099  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
2100  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,
2101  PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
2102  PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last three of these are  PCRE_NO_UTF8_CHECK, PCRE_BSR_ANYCRLF, PCRE_BSR_UNICODE, PCRE_NO_START_OPTIMIZE,
2103  the same as for \fBpcre_exec()\fP, so their description is not repeated here.  PCRE_PARTIAL_HARD, PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART.
2104  .sp  All but the last four of these are exactly the same as for \fBpcre_exec()\fP,
2105    PCRE_PARTIAL  so their description is not repeated here.
2106  .sp  .sp
2107  This has the same general effect as it does for \fBpcre_exec()\fP, but the    PCRE_PARTIAL_HARD
2108  details are slightly different. When PCRE_PARTIAL is set for    PCRE_PARTIAL_SOFT
2109  \fBpcre_dfa_exec()\fP, the return code PCRE_ERROR_NOMATCH is converted into  .sp
2110  PCRE_ERROR_PARTIAL if the end of the subject is reached, there have been no  These have the same general effect as they do for \fBpcre_exec()\fP, but the
2111  complete matches, but there is still at least one matching possibility. The  details are slightly different. When PCRE_PARTIAL_HARD is set for
2112  portion of the string that provided the partial match is set as the first  \fBpcre_dfa_exec()\fP, it returns PCRE_ERROR_PARTIAL if the end of the subject
2113  matching string.  is reached and there is still at least one matching possibility that requires
2114    additional characters. This happens even if some complete matches have also
2115    been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
2116    is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached,
2117    there have been no complete matches, but there is still at least one matching
2118    possibility. The portion of the string that was inspected when the longest
2119    partial match was found is set as the first matching string in both cases.
2120    There is a more detailed discussion of partial and multi-segment matching, with
2121    examples, in the
2122    .\" HREF
2123    \fBpcrepartial\fP
2124    .\"
2125    documentation.
2126  .sp  .sp
2127    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
2128  .sp  .sp
2129  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
2130  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
2131  this is necessarily the shortest possible match at the first possible matching  works, this is necessarily the shortest possible match at the first possible
2132  point in the subject string.  matching point in the subject string.
2133  .sp  .sp
2134    PCRE_DFA_RESTART    PCRE_DFA_RESTART
2135  .sp  .sp
2136  When \fBpcre_dfa_exec()\fP is called with the PCRE_PARTIAL option, and returns  When \fBpcre_dfa_exec()\fP returns a partial match, it is possible to call it
2137  a partial match, it is possible to call it again, with additional subject  again, with additional subject characters, and have it continue with the same
2138  characters, and have it continue with the same match. The PCRE_DFA_RESTART  match. The PCRE_DFA_RESTART option requests this action; when it is set, the
2139  option requests this action; when it is set, the \fIworkspace\fP and  \fIworkspace\fP and \fIwscount\fP options must reference the same vector as
2140  \fIwscount\fP options must reference the same vector as before because data  before because data about the match so far is left in them after a partial
2141  about the match so far is left in them after a partial match. There is more  match. There is more discussion of this facility in the
 discussion of this facility in the  
2142  .\" HREF  .\" HREF
2143  \fBpcrepartial\fP  \fBpcrepartial\fP
2144  .\"  .\"
# Line 1613  the three matched strings are Line 2167  the three matched strings are
2167  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
2168  the number of matched substrings. The substrings themselves are returned in  the number of matched substrings. The substrings themselves are returned in
2169  \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
2170  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
2171  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,
2172  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
2173  data, even though the meaning of the strings is different.)  returns data, even though the meaning of the strings is different.)
2174  .P  .P
2175  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
2176  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 2197  that it does not support, for instance,
2197  .sp  .sp
2198    PCRE_ERROR_DFA_UCOND      (-17)    PCRE_ERROR_DFA_UCOND      (-17)
2199  .sp  .sp
2200  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
2201  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
2202    group. These are not supported.
2203  .sp  .sp
2204    PCRE_ERROR_DFA_UMLIMIT    (-18)    PCRE_ERROR_DFA_UMLIMIT    (-18)
2205  .sp  .sp
# Line 1663  When a recursive subpattern is processed Line 2218  When a recursive subpattern is processed
2218  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This
2219  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
2220  extremely rare, as a vector of size 1000 is used.  extremely rare, as a vector of size 1000 is used.
2221  .P  .
2222  .in 0  .
2223  Last updated: 18 January 2006  .SH "SEE ALSO"
2224  .br  .rs
2225  Copyright (c) 1997-2006 University of Cambridge.  .sp
2226    \fBpcrebuild\fP(3), \fBpcrecallout\fP(3), \fBpcrecpp(3)\fP(3),
2227    \fBpcrematching\fP(3), \fBpcrepartial\fP(3), \fBpcreposix\fP(3),
2228    \fBpcreprecompile\fP(3), \fBpcresample\fP(3), \fBpcrestack\fP(3).
2229    .
2230    .
2231    .SH AUTHOR
2232    .rs
2233    .sp
2234    .nf
2235    Philip Hazel
2236    University Computing Service
2237    Cambridge CB2 3QH, England.
2238    .fi
2239    .
2240    .
2241    .SH REVISION
2242    .rs
2243    .sp
2244    .nf
2245    Last updated: 06 November 2010
2246    Copyright (c) 1997-2010 University of Cambridge.
2247    .fi

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