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

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

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

revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC revision 576 by ph10, Sun Nov 21 18:45:10 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, PCRE_NEWLINE_\fIxxx\fP, PCRE_NO_UTF8_CHECK, and
432    PCRE_NO_START_OPT options can be set at the time of matching as well as at
433    compile time.
434  .P  .P
435  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
436  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
437  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
438  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
439  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
440  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
441  \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
442    error is given. Some errors are not detected until checks are carried out when
443    the whole pattern has been scanned; in this case the offset is set to the end
444    of the pattern.
445    .P
446    Note that the offset is in bytes, not characters, even in UTF-8 mode. It may
447    point into the middle of a UTF-8 character (for example, when
448    PCRE_ERROR_BADUTF8 is returned for an invalid UTF-8 string).
449  .P  .P
450  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
451  \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 492  facility, see the
492  .\"  .\"
493  documentation.  documentation.
494  .sp  .sp
495      PCRE_BSR_ANYCRLF
496      PCRE_BSR_UNICODE
497    .sp
498    These options (which are mutually exclusive) control what the \eR escape
499    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
500    match any Unicode newline sequence. The default is specified when PCRE is
501    built. It can be overridden from within the pattern, or by setting an option
502    when a compiled pattern is matched.
503    .sp
504    PCRE_CASELESS    PCRE_CASELESS
505  .sp  .sp
506  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 517  with UTF-8 support.
517  .sp  .sp
518  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
519  end of the subject string. Without this option, a dollar also matches  end of the subject string. Without this option, a dollar also matches
520  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
521  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.
522  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
523  a pattern.  pattern.
524  .sp  .sp
525    PCRE_DOTALL    PCRE_DOTALL
526  .sp  .sp
527  If this bit is set, a dot metacharater in the pattern matches all characters,  If this bit is set, a dot metacharacter in the pattern matches a character of
528  including newlines. Without it, newlines are excluded. This option is  any value, including one that indicates a newline. However, it only ever
529    matches one character, even if newlines are coded as CRLF. Without this option,
530    a dot does not match when the current position is at a newline. This option is
531  equivalent to Perl's /s option, and it can be changed within a pattern by a  equivalent to Perl's /s option, and it can be changed within a pattern by a
532  (?s) option setting. A negative class such as [^a] always matches a newline  (?s) option setting. A negative class such as [^a] always matches newline
533  character, independent of the setting of this option.  characters, independent of the setting of this option.
534    .sp
535      PCRE_DUPNAMES
536    .sp
537    If this bit is set, names used to identify capturing subpatterns need not be
538    unique. This can be helpful for certain types of pattern when it is known that
539    only one instance of the named subpattern can ever be matched. There are more
540    details of named subpatterns below; see also the
541    .\" HREF
542    \fBpcrepattern\fP
543    .\"
544    documentation.
545  .sp  .sp
546    PCRE_EXTENDED    PCRE_EXTENDED
547  .sp  .sp
548  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
549  ignored except when escaped or inside a character class. Whitespace does not  ignored except when escaped or inside a character class. Whitespace does not
550  include the VT character (code 11). In addition, characters between an  include the VT character (code 11). In addition, characters between an
551  unescaped # outside a character class and the next newline character,  unescaped # outside a character class and the next newline, inclusive, are also
552  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
553  be changed within a pattern by a (?x) option setting.  pattern by a (?x) option setting.
554    .P
555    Which characters are interpreted as newlines
556    is controlled by the options passed to \fBpcre_compile()\fP or by a special
557    sequence at the start of the pattern, as described in the section entitled
558    .\" HTML <a href="pcrepattern.html#newlines">
559    .\" </a>
560    "Newline conventions"
561    .\"
562    in the \fBpcrepattern\fP documentation. Note that the end of this type of
563    comment is a literal newline sequence in the pattern; escape sequences that
564    happen to represent a newline do not count.
565  .P  .P
566  This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
567  Note, however, that this applies only to data characters. Whitespace characters  Note, however, that this applies only to data characters. Whitespace characters
568  may never appear within special character sequences in a pattern, for example  may never appear within special character sequences in a pattern, for example
569  within the sequence (?( which introduces a conditional subpattern.  within the sequence (?( that introduces a conditional subpattern.
570  .sp  .sp
571    PCRE_EXTRA    PCRE_EXTRA
572  .sp  .sp
# Line 476  that is incompatible with Perl, but it i Line 575  that is incompatible with Perl, but it i
575  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
576  special meaning causes an error, thus reserving these combinations for future  special meaning causes an error, thus reserving these combinations for future
577  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
578  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
579  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
580  pattern.  no other features controlled by this option. It can also be set by a (?X)
581    option setting within a pattern.
582  .sp  .sp
583    PCRE_FIRSTLINE    PCRE_FIRSTLINE
584  .sp  .sp
585  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
586  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
587  continue over the newline.  over the newline.
588    .sp
589      PCRE_JAVASCRIPT_COMPAT
590    .sp
591    If this option is set, PCRE's behaviour is changed in some ways so that it is
592    compatible with JavaScript rather than Perl. The changes are as follows:
593    .P
594    (1) A lone closing square bracket in a pattern causes a compile-time error,
595    because this is illegal in JavaScript (by default it is treated as a data
596    character). Thus, the pattern AB]CD becomes illegal when this option is set.
597    .P
598    (2) At run time, a back reference to an unset subpattern group matches an empty
599    string (by default this causes the current matching alternative to fail). A
600    pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
601    an "a" in the subject), whereas it fails by default, for Perl compatibility.
602  .sp  .sp
603    PCRE_MULTILINE    PCRE_MULTILINE
604  .sp  .sp
# Line 496  terminating newline (unless PCRE_DOLLAR_ Line 610  terminating newline (unless PCRE_DOLLAR_
610  Perl.  Perl.
611  .P  .P
612  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
613  match immediately following or immediately before any newline in the subject  match immediately following or immediately before internal newlines in the
614  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
615  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
616  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
617  occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect.  occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect.
618  .sp  .sp
619      PCRE_NEWLINE_CR
620      PCRE_NEWLINE_LF
621      PCRE_NEWLINE_CRLF
622      PCRE_NEWLINE_ANYCRLF
623      PCRE_NEWLINE_ANY
624    .sp
625    These options override the default newline definition that was chosen when PCRE
626    was built. Setting the first or the second specifies that a newline is
627    indicated by a single character (CR or LF, respectively). Setting
628    PCRE_NEWLINE_CRLF specifies that a newline is indicated by the two-character
629    CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three
630    preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
631    that any Unicode newline sequence should be recognized. The Unicode newline
632    sequences are the three just mentioned, plus the single characters VT (vertical
633    tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line
634    separator, U+2028), and PS (paragraph separator, U+2029). The last two are
635    recognized only in UTF-8 mode.
636    .P
637    The newline setting in the options word uses three bits that are treated
638    as a number, giving eight possibilities. Currently only six are used (default
639    plus the five values above). This means that if you set more than one newline
640    option, the combination may or may not be sensible. For example,
641    PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but
642    other combinations may yield unused numbers and cause an error.
643    .P
644    The only time that a line break in a pattern is specially recognized when
645    compiling is when PCRE_EXTENDED is set. CR and LF are whitespace characters,
646    and so are ignored in this mode. Also, an unescaped # outside a character class
647    indicates a comment that lasts until after the next line break sequence. In
648    other circumstances, line break sequences in patterns are treated as literal
649    data.
650    .P
651    The newline option that is set at compile time becomes the default that is used
652    for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.
653    .sp
654    PCRE_NO_AUTO_CAPTURE    PCRE_NO_AUTO_CAPTURE
655  .sp  .sp
656  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 659  were followed by ?: but named parenthese
659  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
660  in Perl.  in Perl.
661  .sp  .sp
662      NO_START_OPTIMIZE
663    .sp
664    This is an option that acts at matching time; that is, it is really an option
665    for \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. If it is set at compile time,
666    it is remembered with the compiled pattern and assumed at matching time. For
667    details see the discussion of PCRE_NO_START_OPTIMIZE
668    .\" HTML <a href="#execoptions">
669    .\" </a>
670    below.
671    .\"
672    .sp
673      PCRE_UCP
674    .sp
675    This option changes the way PCRE processes \eB, \eb, \eD, \ed, \eS, \es, \eW,
676    \ew, and some of the POSIX character classes. By default, only ASCII characters
677    are recognized, but if PCRE_UCP is set, Unicode properties are used instead to
678    classify characters. More details are given in the section on
679    .\" HTML <a href="pcre.html#genericchartypes">
680    .\" </a>
681    generic character types
682    .\"
683    in the
684    .\" HREF
685    \fBpcrepattern\fP
686    .\"
687    page. If you set PCRE_UCP, matching one of the items it affects takes much
688    longer. The option is available only if PCRE has been compiled with Unicode
689    property support.
690    .sp
691    PCRE_UNGREEDY    PCRE_UNGREEDY
692  .sp  .sp
693  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 714  page.
714    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
715  .sp  .sp
716  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
717  automatically checked. If an invalid UTF-8 sequence of bytes is found,  automatically checked. There is a discussion about the
718  \fBpcre_compile()\fP returns an error. If you already know that your pattern is  .\" HTML <a href="pcre.html#utf8strings">
719  valid, and you want to skip this check for performance reasons, you can set the  .\" </a>
720  PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid  validity of UTF-8 strings
721  UTF-8 string as a pattern is undefined. It may cause your program to crash.  .\"
722  Note that this option can also be passed to \fBpcre_exec()\fP and  in the main
723  \fBpcre_dfa_exec()\fP, to suppress the UTF-8 validity checking of subject  .\" HREF
724  strings.  \fBpcre\fP
725    .\"
726    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_compile()\fP
727    returns an error. If you already know that your pattern is valid, and you want
728    to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
729    option. When it is set, the effect of passing an invalid UTF-8 string as a
730    pattern is undefined. It may cause your program to crash. Note that this option
731    can also be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress
732    the UTF-8 validity checking of subject strings.
733  .  .
734  .  .
735  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 551  strings. Line 737  strings.
737  .sp  .sp
738  The following table lists the error codes than may be returned by  The following table lists the error codes than may be returned by
739  \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
740  both compiling functions.  both compiling functions. As PCRE has developed, some error codes have fallen
741    out of use. To avoid confusion, they have not been re-used.
742  .sp  .sp
743     0  no error     0  no error
744     1  \e at end of pattern     1  \e at end of pattern
# Line 563  both compiling functions. Line 750  both compiling functions.
750     7  invalid escape sequence in character class     7  invalid escape sequence in character class
751     8  range out of order in character class     8  range out of order in character class
752     9  nothing to repeat     9  nothing to repeat
753    10  operand of unlimited repeat could match the empty string    10  [this code is not in use]
754    11  internal error: unexpected repeat    11  internal error: unexpected repeat
755    12  unrecognized character after (?    12  unrecognized character after (? or (?-
756    13  POSIX named classes are supported only within a class    13  POSIX named classes are supported only within a class
757    14  missing )    14  missing )
758    15  reference to non-existent subpattern    15  reference to non-existent subpattern
759    16  erroffset passed as NULL    16  erroffset passed as NULL
760    17  unknown option bit(s) set    17  unknown option bit(s) set
761    18  missing ) after comment    18  missing ) after comment
762    19  parentheses nested too deeply    19  [this code is not in use]
763    20  regular expression too large    20  regular expression is too large
764    21  failed to get memory    21  failed to get memory
765    22  unmatched parentheses    22  unmatched parentheses
766    23  internal error: code overflow    23  internal error: code overflow
767    24  unrecognized character after (?<    24  unrecognized character after (?<
768    25  lookbehind assertion is not fixed length    25  lookbehind assertion is not fixed length
769    26  malformed number after (?(    26  malformed number or name after (?(
770    27  conditional group contains more than two branches    27  conditional group contains more than two branches
771    28  assertion expected after (?(    28  assertion expected after (?(
772    29  (?R or (?digits must be followed by )    29  (?R or (?[+-]digits must be followed by )
773    30  unknown POSIX class name    30  unknown POSIX class name
774    31  POSIX collating elements are not supported    31  POSIX collating elements are not supported
775    32  this version of PCRE is not compiled with PCRE_UTF8 support    32  this version of PCRE is not compiled with PCRE_UTF8 support
776    33  spare error    33  [this code is not in use]
777    34  character value in \ex{...} sequence is too large    34  character value in \ex{...} sequence is too large
778    35  invalid condition (?(0)    35  invalid condition (?(0)
779    36  \eC not allowed in lookbehind assertion    36  \eC not allowed in lookbehind assertion
# Line 595  both compiling functions. Line 782  both compiling functions.
782    39  closing ) for (?C expected    39  closing ) for (?C expected
783    40  recursive call could loop indefinitely    40  recursive call could loop indefinitely
784    41  unrecognized character after (?P    41  unrecognized character after (?P
785    42  syntax error after (?P    42  syntax error in subpattern name (missing terminator)
786    43  two named groups have the same name    43  two named subpatterns have the same name
787    44  invalid UTF-8 string    44  invalid UTF-8 string
788    45  support for \eP, \ep, and \eX has not been compiled    45  support for \eP, \ep, and \eX has not been compiled
789    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
790    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
791      48  subpattern name is too long (maximum 32 characters)
792      49  too many named subpatterns (maximum 10000)
793      50  [this code is not in use]
794      51  octal value is greater than \e377 (not in UTF-8 mode)
795      52  internal error: overran compiling workspace
796      53  internal error: previously-checked referenced subpattern
797            not found
798      54  DEFINE group contains more than one branch
799      55  repeating a DEFINE group is not allowed
800      56  inconsistent NEWLINE options
801      57  \eg is not followed by a braced, angle-bracketed, or quoted
802            name/number or by a plain number
803      58  a numbered reference must not be zero
804      59  an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT)
805      60  (*VERB) not recognized
806      61  number is too big
807      62  subpattern name expected
808      63  digit expected after (?+
809      64  ] is an invalid data character in JavaScript compatibility mode
810      65  different names for subpatterns of the same number are
811            not allowed
812      66  (*MARK) must have an argument
813      67  this version of PCRE is not compiled with PCRE_UCP support
814    .sp
815    The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
816    be used if the limits were changed when PCRE was built.
817  .  .
818  .  .
819  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
# Line 619  help speed up matching, \fBpcre_study()\ Line 832  help speed up matching, \fBpcre_study()\
832  results of the study.  results of the study.
833  .P  .P
834  The returned value from \fBpcre_study()\fP can be passed directly to  The returned value from \fBpcre_study()\fP can be passed directly to
835  \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
836  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
837  described  passed; these are described
838  .\" HTML <a href="#extradata">  .\" HTML <a href="#extradata">
839  .\" </a>  .\" </a>
840  below  below
841  .\"  .\"
842  in the section on matching a pattern.  in the section on matching a pattern.
843  .P  .P
844  If studying the pattern does not produce any additional information  If studying the pattern does not produce any useful information,
845  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program
846  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
847  own \fBpcre_extra\fP block.  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.
848  .P  .P
849  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
850  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 864  This is a typical call to \fBpcre_study\
864      0,              /* no options exist */      0,              /* no options exist */
865      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
866  .sp  .sp
867  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
868  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
869  bytes is created.  mean that there are any strings of that length that match, but it does
870    guarantee that no shorter strings match. The value is used by
871    \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP to avoid wasting time by trying to
872    match strings that are shorter than the lower bound. You can find out the value
873    in a calling program via the \fBpcre_fullinfo()\fP function.
874    .P
875    Studying a pattern is also useful for non-anchored patterns that do not have a
876    single fixed starting character. A bitmap of possible starting bytes is
877    created. This speeds up finding a position in the subject at which to start
878    matching.
879    .P
880    The two optimizations just described can be disabled by setting the
881    PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or
882    \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains
883    callouts or (*MARK), and you want to make use of these facilities in cases
884    where matching fails. See the discussion of PCRE_NO_START_OPTIMIZE
885    .\" HTML <a href="#execoptions">
886    .\" </a>
887    below.
888    .\"
889  .  .
890  .  .
891  .\" HTML <a name="localesupport"></a>  .\" HTML <a name="localesupport"></a>
892  .SH "LOCALE SUPPORT"  .SH "LOCALE SUPPORT"
893  .rs  .rs
894  .sp  .sp
895  PCRE handles caseless matching, and determines whether characters are letters  PCRE handles caseless matching, and determines whether characters are letters,
896  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
897  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
898  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
899  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
900  support. The use of locales with Unicode is discouraged.  property support. Alternatively, the PCRE_UCP option can be set at compile
901  .P  time; this causes \ew and friends to use Unicode property support instead of
902  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
903  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
904  and is sufficient for many applications. An alternative set of tables can,  and Unicode, or use locales, but not try to mix the two.
905  however, be supplied. These may be created in a different locale from the  .P
906  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
907  this locale support is expected to die away.  of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.
908    Normally, the internal tables recognize only ASCII characters. However, when
909    PCRE is built, it is possible to cause the internal tables to be rebuilt in the
910    default "C" locale of the local system, which may cause them to be different.
911    .P
912    The internal tables can always be overridden by tables supplied by the
913    application that calls PCRE. These may be created in a different locale from
914    the default. As more and more applications change to using Unicode, the need
915    for this locale support is expected to die away.
916  .P  .P
917  External tables are built by calling the \fBpcre_maketables()\fP function,  External tables are built by calling the \fBpcre_maketables()\fP function,
918  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 925  the following code could be used:
925    tables = pcre_maketables();    tables = pcre_maketables();
926    re = pcre_compile(..., tables);    re = pcre_compile(..., tables);
927  .sp  .sp
928    The locale name "fr_FR" is used on Linux and other Unix-like systems; if you
929    are using Windows, the name for the French locale is "french".
930    .P
931  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
932  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
933  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 974  check against passing an arbitrary memor
974  \fBpcre_fullinfo()\fP, to obtain the length of the compiled pattern:  \fBpcre_fullinfo()\fP, to obtain the length of the compiled pattern:
975  .sp  .sp
976    int rc;    int rc;
977    unsigned long int length;    size_t length;
978    rc = pcre_fullinfo(    rc = pcre_fullinfo(
979      re,               /* result of pcre_compile() */      re,               /* result of pcre_compile() */
980      pe,               /* result of pcre_study(), or NULL */      pe,               /* result of pcre_study(), or NULL */
# Line 763  a NULL table pointer. Line 1006  a NULL table pointer.
1006    PCRE_INFO_FIRSTBYTE    PCRE_INFO_FIRSTBYTE
1007  .sp  .sp
1008  Return information about the first byte of any matched string, for a  Return information about the first byte of any matched string, for a
1009  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
1010  old name is still recognized for backwards compatibility.)  variable. (This option used to be called PCRE_INFO_FIRSTCHAR; the old name is
1011    still recognized for backwards compatibility.)
1012  .P  .P
1013  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
1014  (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  
1015  .sp  .sp
1016  (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
1017  starts with "^", or  starts with "^", or
# Line 787  table indicating a fixed set of bytes fo Line 1030  table indicating a fixed set of bytes fo
1030  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
1031  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
1032  .sp  .sp
1033      PCRE_INFO_HASCRORLF
1034    .sp
1035    Return 1 if the pattern contains any explicit matches for CR or LF characters,
1036    otherwise 0. The fourth argument should point to an \fBint\fP variable. An
1037    explicit match is either a literal CR or LF character, or \er or \en.
1038    .sp
1039      PCRE_INFO_JCHANGED
1040    .sp
1041    Return 1 if the (?J) or (?-J) option setting is used in the pattern, otherwise
1042    0. The fourth argument should point to an \fBint\fP variable. (?J) and
1043    (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
1044    .sp
1045    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
1046  .sp  .sp
1047  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 1052  follows something of variable length. Fo
1052  /^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
1053  is -1.  is -1.
1054  .sp  .sp
1055      PCRE_INFO_MINLENGTH
1056    .sp
1057    If the pattern was studied and a minimum length for matching subject strings
1058    was computed, its value is returned. Otherwise the returned value is -1. The
1059    value is a number of characters, not bytes (this may be relevant in UTF-8
1060    mode). The fourth argument should point to an \fBint\fP variable. A
1061    non-negative value is a lower bound to the length of any matching string. There
1062    may not be any strings of that length that do actually match, but every string
1063    that does match is at least that long.
1064    .sp
1065    PCRE_INFO_NAMECOUNT    PCRE_INFO_NAMECOUNT
1066    PCRE_INFO_NAMEENTRYSIZE    PCRE_INFO_NAMEENTRYSIZE
1067    PCRE_INFO_NAMETABLE    PCRE_INFO_NAMETABLE
1068  .sp  .sp
1069  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
1070  names are just an additional way of identifying the parentheses, which still  names are just an additional way of identifying the parentheses, which still
1071  acquire numbers. A convenience function called \fBpcre_get_named_substring()\fP  acquire numbers. Several convenience functions such as
1072  is provided for extracting an individual captured substring by name. It is also  \fBpcre_get_named_substring()\fP are provided for extracting captured
1073  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
1074  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
1075  \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,
1076  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
1077    values.
1078  .P  .P
1079  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
1080  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 1082  entry; both of these return an \fBint\fP
1082  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
1083  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
1084  are the number of the capturing parenthesis, most significant byte first. The  are the number of the capturing parenthesis, most significant byte first. The
1085  rest of the entry is the corresponding name, zero terminated. The names are in  rest of the entry is the corresponding name, zero terminated.
1086  alphabetical order. For example, consider the following pattern (assume  .P
1087  PCRE_EXTENDED is set, so white space - including newlines - is ignored):  The names are in alphabetical order. Duplicate names may appear if (?| is used
1088    to create multiple groups with the same number, as described in the
1089    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1090    .\" </a>
1091    section on duplicate subpattern numbers
1092    .\"
1093    in the
1094    .\" HREF
1095    \fBpcrepattern\fP
1096    .\"
1097    page. Duplicate names for subpatterns with different numbers are permitted only
1098    if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the
1099    table in the order in which they were found in the pattern. In the absence of
1100    (?| this is the order of increasing number; when (?| is used this is not
1101    necessarily the case because later subpatterns may have lower numbers.
1102    .P
1103    As a simple example of the name/number table, consider the following pattern
1104    (assume PCRE_EXTENDED is set, so white space - including newlines - is
1105    ignored):
1106  .sp  .sp
1107  .\" JOIN  .\" JOIN
1108    (?P<date> (?P<year>(\ed\ed)?\ed\ed) -    (?<date> (?<year>(\ed\ed)?\ed\ed) -
1109    (?P<month>\ed\ed) - (?P<day>\ed\ed) )    (?<month>\ed\ed) - (?<day>\ed\ed) )
1110  .sp  .sp
1111  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
1112  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 1118  bytes shows in hexadecimal, and undefine
1118    00 02 y  e  a  r  00 ??    00 02 y  e  a  r  00 ??
1119  .sp  .sp
1120  When writing code to extract data from named subpatterns using the  When writing code to extract data from named subpatterns using the
1121  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
1122  different for each compiled pattern.  different for each compiled pattern.
1123  .sp  .sp
1124      PCRE_INFO_OKPARTIAL
1125    .sp
1126    Return 1 if the pattern can be used for partial matching with
1127    \fBpcre_exec()\fP, otherwise 0. The fourth argument should point to an
1128    \fBint\fP variable. From release 8.00, this always returns 1, because the
1129    restrictions that previously applied to partial matching have been lifted. The
1130    .\" HREF
1131    \fBpcrepartial\fP
1132    .\"
1133    documentation gives details of partial matching.
1134    .sp
1135    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
1136  .sp  .sp
1137  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
1138  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
1139  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
1140  top-level option settings within the pattern itself.  top-level option settings at the start of the pattern itself. In other words,
1141    they are the options that will be in force when matching starts. For example,
1142    if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the
1143    result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED.
1144  .P  .P
1145  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
1146  alternatives begin with one of the following:  alternatives begin with one of the following:
# Line 869  variable. Line 1167  variable.
1167  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
1168  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
1169  \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
1170  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
1171    study data, zero is returned. The fourth argument should point to a
1172  \fBsize_t\fP variable.  \fBsize_t\fP variable.
1173  .  .
1174  .  .
# Line 931  is different. (This seems a highly unlik Line 1230  is different. (This seems a highly unlik
1230  .P  .P
1231  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
1232  compiled pattern, which is passed in the \fIcode\fP argument. If the  compiled pattern, which is passed in the \fIcode\fP argument. If the
1233  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
1234  \fIextra\fP argument. This function is the main matching facility of the  \fIextra\fP argument. This function is the main matching facility of the
1235  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
1236  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 1280  fields (not necessarily in this order):
1280    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1281    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1282    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1283      unsigned char **\fImark\fP;
1284  .sp  .sp
1285  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
1286  are set. The flag bits are:  are set. The flag bits are:
# Line 990  are set. The flag bits are: Line 1290  are set. The flag bits are:
1290    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1291    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_CALLOUT_DATA
1292    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
1293      PCRE_EXTRA_MARK
1294  .sp  .sp
1295  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
1296  \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 1300  the block by setting the other fields an
1300  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
1301  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,
1302  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
1303  classic example is the use of nested unlimited repeats.  classic example is a pattern that uses nested unlimited repeats.
1304  .P  .P
1305  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly
1306  (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 1333  with a \fBpcre_extra\fP block in which \
1333  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
1334  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.  is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.
1335  .P  .P
1336  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,
1337  which is described in the  and is described in the
1338  .\" HREF  .\" HREF
1339  \fBpcrecallout\fP  \fBpcrecallout\fP
1340  .\"  .\"
# Line 1052  called. See the Line 1353  called. See the
1353  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1354  .\"  .\"
1355  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1356    .P
1357    If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must
1358    be set to point to a \fBchar *\fP variable. If the pattern contains any
1359    backtracking control verbs such as (*MARK:NAME), and the execution ends up with
1360    a name to pass back, a pointer to the name string (zero terminated) is placed
1361    in the variable pointed to by the \fImark\fP field. The names are within the
1362    compiled pattern; if you wish to retain such a name you must copy it before
1363    freeing the memory of a compiled pattern. If there is no name to pass back, the
1364    variable pointed to by the \fImark\fP field set to NULL. For details of the
1365    backtracking control verbs, see the section entitled
1366    .\" HTML <a href="pcrepattern#backtrackcontrol">
1367    .\" </a>
1368    "Backtracking control"
1369    .\"
1370    in the
1371    .\" HREF
1372    \fBpcrepattern\fP
1373    .\"
1374    documentation.
1375    .
1376  .  .
1377    .\" HTML <a name="execoptions"></a>
1378  .SS "Option bits for \fBpcre_exec()\fP"  .SS "Option bits for \fBpcre_exec()\fP"
1379  .rs  .rs
1380  .sp  .sp
1381  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
1382  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,
1383  PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1384    PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
1385    PCRE_PARTIAL_HARD.
1386  .sp  .sp
1387    PCRE_ANCHORED    PCRE_ANCHORED
1388  .sp  .sp
# Line 1067  matching position. If a pattern was comp Line 1391  matching position. If a pattern was comp
1391  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
1392  matching time.  matching time.
1393  .sp  .sp
1394      PCRE_BSR_ANYCRLF
1395      PCRE_BSR_UNICODE
1396    .sp
1397    These options (which are mutually exclusive) control what the \eR escape
1398    sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1399    match any Unicode newline sequence. These options override the choice that was
1400    made or defaulted when the pattern was compiled.
1401    .sp
1402      PCRE_NEWLINE_CR
1403      PCRE_NEWLINE_LF
1404      PCRE_NEWLINE_CRLF
1405      PCRE_NEWLINE_ANYCRLF
1406      PCRE_NEWLINE_ANY
1407    .sp
1408    These options override the newline definition that was chosen or defaulted when
1409    the pattern was compiled. For details, see the description of
1410    \fBpcre_compile()\fP above. During matching, the newline choice affects the
1411    behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1412    the way the match position is advanced after a match failure for an unanchored
1413    pattern.
1414    .P
1415    When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a
1416    match attempt for an unanchored pattern fails when the current position is at a
1417    CRLF sequence, and the pattern contains no explicit matches for CR or LF
1418    characters, the match position is advanced by two characters instead of one, in
1419    other words, to after the CRLF.
1420    .P
1421    The above rule is a compromise that makes the most common cases work as
1422    expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1423    set), it does not match the string "\er\enA" because, after failing at the
1424    start, it skips both the CR and the LF before retrying. However, the pattern
1425    [\er\en]A does match that string, because it contains an explicit CR or LF
1426    reference, and so advances only by one character after the first failure.
1427    .P
1428    An explicit match for CR of LF is either a literal appearance of one of those
1429    characters, or one of the \er or \en escape sequences. Implicit matches such as
1430    [^X] do not count, nor does \es (which includes CR and LF in the characters
1431    that it matches).
1432    .P
1433    Notwithstanding the above, anomalous effects may still occur when CRLF is a
1434    valid newline sequence and explicit \er or \en escapes appear in the pattern.
1435    .sp
1436    PCRE_NOTBOL    PCRE_NOTBOL
1437  .sp  .sp
1438  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 1457  match the empty string, the entire match
1457  .sp  .sp
1458    a?b?    a?b?
1459  .sp  .sp
1460  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
1461  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
1462  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".
1463    .sp
1464      PCRE_NOTEMPTY_ATSTART
1465    .sp
1466    This is like PCRE_NOTEMPTY, except that an empty string match that is not at
1467    the start of the subject is permitted. If the pattern is anchored, such a match
1468    can occur only if the pattern contains \eK.
1469    .P
1470    Perl has no direct equivalent of PCRE_NOTEMPTY or PCRE_NOTEMPTY_ATSTART, but it
1471    does make a special case of a pattern match of the empty string within its
1472    \fBsplit()\fP function, and when using the /g modifier. It is possible to
1473    emulate Perl's behaviour after matching a null string by first trying the match
1474    again at the same offset with PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED, and then
1475    if that fails, by advancing the starting offset (see below) and trying an
1476    ordinary match again. There is some code that demonstrates how to do this in
1477    the
1478    .\" HREF
1479    \fBpcredemo\fP
1480    .\"
1481    sample program. In the most general case, you have to check to see if the
1482    newline convention recognizes CRLF as a newline, and if so, and the current
1483    character is CR followed by LF, advance the starting offset by two characters
1484    instead of one.
1485    .sp
1486      PCRE_NO_START_OPTIMIZE
1487    .sp
1488    There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1489    a match, in order to speed up the process. For example, if it is known that an
1490    unanchored match must start with a specific character, it searches the subject
1491    for that character, and fails immediately if it cannot find it, without
1492    actually running the main matching function. This means that a special item
1493    such as (*COMMIT) at the start of a pattern is not considered until after a
1494    suitable starting point for the match has been found. When callouts or (*MARK)
1495    items are in use, these "start-up" optimizations can cause them to be skipped
1496    if the pattern is never actually used. The start-up optimizations are in effect
1497    a pre-scan of the subject that takes place before the pattern is run.
1498    .P
1499    The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1500    causing performance to suffer, but ensuring that in cases where the result is
1501    "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
1502    are considered at every possible starting position in the subject string. If
1503    PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching
1504    time.
1505  .P  .P
1506  Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case  Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
1507  of a pattern match of the empty string within its \fBsplit()\fP function, and  Consider the pattern
1508  when using the /g modifier. It is possible to emulate Perl's behaviour after  .sp
1509  matching a null string by first trying the match again at the same offset with    (*COMMIT)ABC
1510  PCRE_NOTEMPTY and PCRE_ANCHORED, and then if that fails by advancing the  .sp
1511  starting offset (see below) and trying an ordinary match again. There is some  When this is compiled, PCRE records the fact that a match must start with the
1512  code that demonstrates how to do this in the \fIpcredemo.c\fP sample program.  character "A". Suppose the subject string is "DEFABC". The start-up
1513    optimization scans along the subject, finds "A" and runs the first match
1514    attempt from there. The (*COMMIT) item means that the pattern must match the
1515    current starting position, which in this case, it does. However, if the same
1516    match is run with PCRE_NO_START_OPTIMIZE set, the initial scan along the
1517    subject string does not happen. The first match attempt is run starting from
1518    "D" and when this fails, (*COMMIT) prevents any further matches being tried, so
1519    the overall result is "no match". If the pattern is studied, more start-up
1520    optimizations may be used. For example, a minimum length for the subject may be
1521    recorded. Consider the pattern
1522    .sp
1523      (*MARK:A)(X|Y)
1524    .sp
1525    The minimum length for a match is one character. If the subject is "ABC", there
1526    will be attempts to match "ABC", "BC", "C", and then finally an empty string.
1527    If the pattern is studied, the final attempt does not take place, because PCRE
1528    knows that the subject is too short, and so the (*MARK) is never encountered.
1529    In this case, studying the pattern does not affect the overall match result,
1530    which is still "no match", but it does affect the auxiliary information that is
1531    returned.
1532  .sp  .sp
1533    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
1534  .sp  .sp
1535  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
1536  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1537  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
1538  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
1539  \fBpcre_exec()\fP returns the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP  strings in the
1540  contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.  .\" HTML <a href="pcre.html#utf8strings">
1541    .\" </a>
1542    section on UTF-8 support
1543    .\"
1544    in the main
1545    .\" HREF
1546    \fBpcre\fP
1547    .\"
1548    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1549    the error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is
1550    a truncated UTF-8 character at the end of the subject, PCRE_ERROR_SHORTUTF8. If
1551    \fIstartoffset\fP contains a value that does not point to the start of a UTF-8
1552    character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
1553    returned.
1554  .P  .P
1555  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
1556  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
1557  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
1558  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
1559  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
1560  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
1561  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
1562  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
1563  UTF-8 character, is undefined. Your program may crash.  undefined. Your program may crash.
1564  .sp  .sp
1565    PCRE_PARTIAL    PCRE_PARTIAL_HARD
1566  .sp    PCRE_PARTIAL_SOFT
1567  This option turns on the partial matching feature. If the subject string fails  .sp
1568  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
1569  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
1570  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
1571  characters), \fBpcre_exec()\fP returns PCRE_ERROR_PARTIAL instead of  not enough subject characters to complete the match. If this happens when
1572  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
1573  may appear in the pattern. These are discussed in the  testing any remaining alternatives. Only if no complete match can be found is
1574    PCRE_ERROR_PARTIAL returned instead of PCRE_ERROR_NOMATCH. In other words,
1575    PCRE_PARTIAL_SOFT says that the caller is prepared to handle a partial match,
1576    but only if no complete match can be found.
1577    .P
1578    If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a
1579    partial match is found, \fBpcre_exec()\fP immediately returns
1580    PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,
1581    when PCRE_PARTIAL_HARD is set, a partial match is considered to be more
1582    important that an alternative complete match.
1583    .P
1584    In both cases, the portion of the string that was inspected when the partial
1585    match was found is set as the first matching string. There is a more detailed
1586    discussion of partial and multi-segment matching, with examples, in the
1587  .\" HREF  .\" HREF
1588  \fBpcrepartial\fP  \fBpcrepartial\fP
1589  .\"  .\"
1590  documentation.  documentation.
1591  .  .
1592    .
1593  .SS "The string to be matched by \fBpcre_exec()\fP"  .SS "The string to be matched by \fBpcre_exec()\fP"
1594  .rs  .rs
1595  .sp  .sp
1596  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
1597  \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
1598  \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
1599  UTF-8 character. Unlike the pattern string, the subject may contain binary zero  subject, \fBpcre_exec()\fP returns PCRE_ERROR_BADOFFSET. When the starting
1600  bytes. When the starting offset is zero, the search for a match starts at the  offset is zero, the search for a match starts at the beginning of the subject,
1601  beginning of the subject, and this is by far the most common case.  and this is by far the most common case. In UTF-8 mode, the byte offset must
1602    point to the start of a UTF-8 character (or the end of the subject). Unlike the
1603    pattern string, the subject may contain binary zero bytes.
1604  .P  .P
1605  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
1606  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 1620  start of the subject, which is deemed to
1620  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
1621  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.
1622  .P  .P
1623    Finding all the matches in a subject is tricky when the pattern can match an
1624    empty string. It is possible to emulate Perl's /g behaviour by first trying the
1625    match again at the same offset, with the PCRE_NOTEMPTY_ATSTART and
1626    PCRE_ANCHORED options, and then if that fails, advancing the starting offset
1627    and trying an ordinary match again. There is some code that demonstrates how to
1628    do this in the
1629    .\" HREF
1630    \fBpcredemo\fP
1631    .\"
1632    sample program. In the most general case, you have to check to see if the
1633    newline convention recognizes CRLF as a newline, and if so, and the current
1634    character is CR followed by LF, advance the starting offset by two characters
1635    instead of one.
1636    .P
1637  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
1638  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
1639  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.
1640  .  .
1641    .
1642  .SS "How \fBpcre_exec()\fP returns captured substrings"  .SS "How \fBpcre_exec()\fP returns captured substrings"
1643  .rs  .rs
1644  .sp  .sp
# Line 1178  pattern. Following the usage in Jeffrey Line 1649  pattern. Following the usage in Jeffrey
1649  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
1650  kinds of parenthesized subpattern that do not cause substrings to be captured.  kinds of parenthesized subpattern that do not cause substrings to be captured.
1651  .P  .P
1652  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
1653  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
1654  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
1655  this argument is NOT the size of \fIovector\fP in bytes.  argument is NOT the size of \fIovector\fP in bytes.
1656  .P  .P
1657  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,
1658  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
1659  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,  used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1660  and is not available for passing back information. The length passed in  and is not available for passing back information. The number passed in
1661  \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
1662  rounded down.  rounded down.
1663  .P  .P
1664  When a match is successful, information about captured substrings is returned  When a match is successful, information about captured substrings is returned
1665  in pairs of integers, starting at the beginning of \fIovector\fP, and  in pairs of integers, starting at the beginning of \fIovector\fP, and
1666  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
1667  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
1668  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
1669  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
1670  subject string matched by the entire pattern. The next pair is used for the  mode. They are not character counts.
1671  first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fP  .P
1672  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
1673  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
1674  just the first pair of offsets has been set.  used for the first capturing subpattern, and so on. The value returned by
1675  .P  \fBpcre_exec()\fP is one more than the highest numbered pair that has been set.
1676  Some convenience functions are provided for extracting the captured substrings  For example, if two substrings have been captured, the returned value is 3. If
1677  as separate strings. These are described in the following section.  there are no capturing subpatterns, the return value from a successful match is
1678  .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.  
1679  .P  .P
1680  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
1681  string that it matched that is returned.  string that it matched that is returned.
1682  .P  .P
1683  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
1684  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
1685  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,
1686  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
1687  \fIovecsize\fP as zero. However, if the pattern contains back references and  \fIovecsize\fP as zero. However, if the pattern contains back references and
1688  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
1689  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
1690  advisable to supply an \fIovector\fP.  advisable to supply an \fIovector\fP.
1691  .P  .P
1692  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
1693  subpatterns there are in a compiled pattern. The smallest size for  subpatterns there are in a compiled pattern. The smallest size for
1694  \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
1695  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.
1696    .P
1697    It is possible for capturing subpattern number \fIn+1\fP to match some part of
1698    the subject when subpattern \fIn\fP has not been used at all. For example, if
1699    the string "abc" is matched against the pattern (a|(z))(bc) the return from the
1700    function is 4, and subpatterns 1 and 3 are matched, but 2 is not. When this
1701    happens, both values in the offset pairs corresponding to unused subpatterns
1702    are set to -1.
1703    .P
1704    Offset values that correspond to unused subpatterns at the end of the
1705    expression are also set to -1. For example, if the string "abc" is matched
1706    against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not matched. The
1707    return from the function is 2, because the highest used capturing subpattern
1708    number is 1, and the offsets for for the second and third capturing subpatterns
1709    (assuming the vector is large enough, of course) are set to -1.
1710    .P
1711    \fBNote\fP: Elements of \fIovector\fP that do not correspond to capturing
1712    parentheses in the pattern are never changed. That is, if a pattern contains
1713    \fIn\fP capturing parentheses, no more than \fIovector[0]\fP to
1714    \fIovector[2n+1]\fP are set by \fBpcre_exec()\fP. The other elements retain
1715    whatever values they previously had.
1716    .P
1717    Some convenience functions are provided for extracting the captured substrings
1718    as separate strings. These are described below.
1719  .  .
1720  .\" HTML <a name="errorlist"></a>  .\" HTML <a name="errorlist"></a>
1721  .SS "Return values from \fBpcre_exec()\fP"  .SS "Error return values from \fBpcre_exec()\fP"
1722  .rs  .rs
1723  .sp  .sp
1724  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 1745  compiled in an environment of one endian
1745  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
1746  not present.  not present.
1747  .sp  .sp
1748    PCRE_ERROR_UNKNOWN_NODE   (-5)    PCRE_ERROR_UNKNOWN_OPCODE (-5)
1749  .sp  .sp
1750  While running the pattern match, an unknown item was encountered in the  While running the pattern match, an unknown item was encountered in the
1751  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 1758  If a pattern contains back references, b
1758  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
1759  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
1760  automatically freed at the end of matching.  automatically freed at the end of matching.
1761    .P
1762    This error is also given if \fBpcre_stack_malloc()\fP fails in
1763    \fBpcre_exec()\fP. This can happen only when PCRE has been compiled with
1764    \fB--disable-stack-for-recursion\fP.
1765  .sp  .sp
1766    PCRE_ERROR_NOSUBSTRING    (-7)    PCRE_ERROR_NOSUBSTRING    (-7)
1767  .sp  .sp
# Line 1282  The backtracking limit, as specified by Line 1775  The backtracking limit, as specified by
1775  \fBpcre_extra\fP structure (or defaulted) was reached. See the description  \fBpcre_extra\fP structure (or defaulted) was reached. See the description
1776  above.  above.
1777  .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  
1778    PCRE_ERROR_CALLOUT        (-9)    PCRE_ERROR_CALLOUT        (-9)
1779  .sp  .sp
1780  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 1787  documentation for details.
1787    PCRE_ERROR_BADUTF8        (-10)    PCRE_ERROR_BADUTF8        (-10)
1788  .sp  .sp
1789  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.
1790    However, if PCRE_PARTIAL_HARD is set and the problem is a truncated UTF-8
1791    character at the end of the subject, PCRE_ERROR_SHORTUTF8 is used instead.
1792  .sp  .sp
1793    PCRE_ERROR_BADUTF8_OFFSET (-11)    PCRE_ERROR_BADUTF8_OFFSET (-11)
1794  .sp  .sp
1795  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
1796  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
1797    end of the subject.
1798  .sp  .sp
1799    PCRE_ERROR_PARTIAL        (-12)    PCRE_ERROR_PARTIAL        (-12)
1800  .sp  .sp
# Line 1316  documentation for details of partial mat Line 1806  documentation for details of partial mat
1806  .sp  .sp
1807    PCRE_ERROR_BADPARTIAL     (-13)    PCRE_ERROR_BADPARTIAL     (-13)
1808  .sp  .sp
1809  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
1810  are not supported for partial matching. See the  option was used with a compiled pattern containing items that were not
1811  .\" HREF  supported for partial matching. From release 8.00 onwards, there are no
1812  \fBpcrepartial\fP  restrictions on partial matching.
 .\"  
 documentation for details of partial matching.  
1813  .sp  .sp
1814    PCRE_ERROR_INTERNAL       (-14)    PCRE_ERROR_INTERNAL       (-14)
1815  .sp  .sp
# Line 1331  in PCRE or by overwriting of the compile Line 1819  in PCRE or by overwriting of the compile
1819    PCRE_ERROR_BADCOUNT       (-15)    PCRE_ERROR_BADCOUNT       (-15)
1820  .sp  .sp
1821  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.
1822    .sp
1823      PCRE_ERROR_RECURSIONLIMIT (-21)
1824    .sp
1825    The internal recursion limit, as specified by the \fImatch_limit_recursion\fP
1826    field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the
1827    description above.
1828    .sp
1829      PCRE_ERROR_BADNEWLINE     (-23)
1830    .sp
1831    An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
1832    .sp
1833      PCRE_ERROR_BADOFFSET      (-24)
1834    .sp
1835    The value of \fIstartoffset\fP was negative or greater than the length of the
1836    subject, that is, the value in \fIlength\fP.
1837    .sp
1838      PCRE_ERROR_SHORTUTF8      (-25)
1839    .sp
1840    The subject string ended with an incomplete (truncated) UTF-8 character, and
1841    the PCRE_PARTIAL_HARD option was set. Without this option, PCRE_ERROR_BADUTF8
1842    is returned in this situation.
1843    .P
1844    Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
1845  .  .
1846  .  .
1847  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 1342  This error is given if the value of the Line 1853  This error is given if the value of the
1853  .ti +5n  .ti +5n
1854  .B int \fIbuffersize\fP);  .B int \fIbuffersize\fP);
1855  .PP  .PP
 .br  
1856  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,  .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,
1857  .ti +5n  .ti +5n
1858  .B int \fIstringcount\fP, int \fIstringnumber\fP,  .B int \fIstringcount\fP, int \fIstringnumber\fP,
1859  .ti +5n  .ti +5n
1860  .B const char **\fIstringptr\fP);  .B const char **\fIstringptr\fP);
1861  .PP  .PP
 .br  
1862  .B int pcre_get_substring_list(const char *\fIsubject\fP,  .B int pcre_get_substring_list(const char *\fIsubject\fP,
1863  .ti +5n  .ti +5n
1864  .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 1869  Captured substrings can be accessed dire
1869  \fBpcre_get_substring_list()\fP are provided for extracting captured substrings  \fBpcre_get_substring_list()\fP are provided for extracting captured substrings
1870  as new, separate, zero-terminated strings. These functions identify substrings  as new, separate, zero-terminated strings. These functions identify substrings
1871  by number. The next section describes functions for extracting named  by number. The next section describes functions for extracting named
1872  substrings. A substring that contains a binary zero is correctly extracted and  substrings.
1873  has a further zero added on the end, but the result is not, of course,  .P
1874  a C string.  A substring that contains a binary zero is correctly extracted and has a
1875    further zero added on the end, but the result is not, of course, a C string.
1876    However, you can process such a string by referring to the length that is
1877    returned by \fBpcre_copy_substring()\fP and \fBpcre_get_substring()\fP.
1878    Unfortunately, the interface to \fBpcre_get_substring_list()\fP is not adequate
1879    for handling strings containing binary zeros, because the end of the final
1880    string is not independently indicated.
1881  .P  .P
1882  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:
1883  \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 1897  the string is placed in \fIbuffer\fP, wh
1897  \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
1898  obtained via \fBpcre_malloc\fP, and its address is returned via  obtained via \fBpcre_malloc\fP, and its address is returned via
1899  \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
1900  including the terminating zero, or one of  including the terminating zero, or one of these error codes:
1901  .sp  .sp
1902    PCRE_ERROR_NOMEMORY       (-6)    PCRE_ERROR_NOMEMORY       (-6)
1903  .sp  .sp
# Line 1398  and builds a list of pointers to them. A Line 1913  and builds a list of pointers to them. A
1913  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
1914  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
1915  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
1916  function is zero if all went well, or  function is zero if all went well, or the error code
1917  .sp  .sp
1918    PCRE_ERROR_NOMEMORY       (-6)    PCRE_ERROR_NOMEMORY       (-6)
1919  .sp  .sp
# Line 1417  a previous call of \fBpcre_get_substring Line 1932  a previous call of \fBpcre_get_substring
1932  \fBpcre_get_substring_list()\fP, respectively. They do nothing more than call  \fBpcre_get_substring_list()\fP, respectively. They do nothing more than call
1933  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
1934  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
1935  linked via a special interface to another programming language which cannot use  linked via a special interface to another programming language that cannot use
1936  \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
1937  provided.  provided.
1938  .  .
# Line 1429  provided. Line 1944  provided.
1944  .ti +5n  .ti +5n
1945  .B const char *\fIname\fP);  .B const char *\fIname\fP);
1946  .PP  .PP
 .br  
1947  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,
1948  .ti +5n  .ti +5n
1949  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 1438  provided. Line 1952  provided.
1952  .ti +5n  .ti +5n
1953  .B char *\fIbuffer\fP, int \fIbuffersize\fP);  .B char *\fIbuffer\fP, int \fIbuffersize\fP);
1954  .PP  .PP
 .br  
1955  .B int pcre_get_named_substring(const pcre *\fIcode\fP,  .B int pcre_get_named_substring(const pcre *\fIcode\fP,
1956  .ti +5n  .ti +5n
1957  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 1450  provided. Line 1963  provided.
1963  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.
1964  For example, for this pattern  For example, for this pattern
1965  .sp  .sp
1966    (a+)b(?P<xxx>\ed+)...    (a+)b(?<xxx>\ed+)...
1967  .sp  .sp
1968  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
1969  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
1970  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
1971    pattern, and the second is the name. The yield of the function is the
1972  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
1973  that name.  that name.
1974  .P  .P
# Line 1462  Given the number, you can extract the su Line 1976  Given the number, you can extract the su
1976  functions described in the previous section. For convenience, there are also  functions described in the previous section. For convenience, there are also
1977  two functions that do the whole job.  two functions that do the whole job.
1978  .P  .P
1979  Most of the arguments of \fIpcre_copy_named_substring()\fP and  Most of the arguments of \fBpcre_copy_named_substring()\fP and
1980  \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
1981  functions that extract by number. As these are described in the previous  functions that extract by number. As these are described in the previous
1982  section, they are not re-described here. There are just two differences:  section, they are not re-described here. There are just two differences:
1983  .P  .P
# Line 1473  pattern. This is needed in order to gain Line 1987  pattern. This is needed in order to gain
1987  translation table.  translation table.
1988  .P  .P
1989  These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they  These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they
1990  then call \fIpcre_copy_substring()\fP or \fIpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1991  appropriate.  appropriate. \fBNOTE:\fP If PCRE_DUPNAMES is set and there are duplicate names,
1992    the behaviour may not be what you want (see the next section).
1993    .P
1994    \fBWarning:\fP If the pattern uses the (?| feature to set up multiple
1995    subpatterns with the same number, as described in the
1996    .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1997    .\" </a>
1998    section on duplicate subpattern numbers
1999    .\"
2000    in the
2001    .\" HREF
2002    \fBpcrepattern\fP
2003    .\"
2004    page, you cannot use names to distinguish the different subpatterns, because
2005    names are not included in the compiled code. The matching process uses only
2006    numbers. For this reason, the use of different names for subpatterns of the
2007    same number causes an error at compile time.
2008    .
2009    .SH "DUPLICATE SUBPATTERN NAMES"
2010    .rs
2011    .sp
2012    .B int pcre_get_stringtable_entries(const pcre *\fIcode\fP,
2013    .ti +5n
2014    .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
2015    .PP
2016    When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns
2017    are not required to be unique. (Duplicate names are always allowed for
2018    subpatterns with the same number, created by using the (?| feature. Indeed, if
2019    such subpatterns are named, they are required to use the same names.)
2020    .P
2021    Normally, patterns with duplicate names are such that in any one match, only
2022    one of the named subpatterns participates. An example is shown in the
2023    .\" HREF
2024    \fBpcrepattern\fP
2025    .\"
2026    documentation.
2027    .P
2028    When duplicates are present, \fBpcre_copy_named_substring()\fP and
2029    \fBpcre_get_named_substring()\fP return the first substring corresponding to
2030    the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is
2031    returned; no data is returned. The \fBpcre_get_stringnumber()\fP function
2032    returns one of the numbers that are associated with the name, but it is not
2033    defined which it is.
2034    .P
2035    If you want to get full details of all captured substrings for a given name,
2036    you must use the \fBpcre_get_stringtable_entries()\fP function. The first
2037    argument is the compiled pattern, and the second is the name. The third and
2038    fourth are pointers to variables which are updated by the function. After it
2039    has run, they point to the first and last entries in the name-to-number table
2040    for the given name. The function itself returns the length of each entry, or
2041    PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is
2042    described above in the section entitled \fIInformation about a pattern\fP.
2043    Given all the relevant entries for the name, you can extract each of their
2044    numbers, and hence the captured data, if any.
2045  .  .
2046  .  .
2047  .SH "FINDING ALL POSSIBLE MATCHES"  .SH "FINDING ALL POSSIBLE MATCHES"
# Line 1512  will yield PCRE_ERROR_NOMATCH. Line 2079  will yield PCRE_ERROR_NOMATCH.
2079  .B int *\fIworkspace\fP, int \fIwscount\fP);  .B int *\fIworkspace\fP, int \fIwscount\fP);
2080  .P  .P
2081  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
2082  a compiled pattern, using a "DFA" matching algorithm. This has different  a compiled pattern, using a matching algorithm that scans the subject string
2083  characteristics to the normal algorithm, and is not compatible with Perl. Some  just once, and does not backtrack. This has different characteristics to the
2084  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
2085  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
2086  matching algorithms, see the  matching can be useful. For a discussion of the two matching algorithms, and a
2087    list of features that \fBpcre_dfa_exec()\fP does not support, see the
2088  .\" HREF  .\" HREF
2089  \fBpcrematching\fP  \fBpcrematching\fP
2090  .\"  .\"
# Line 1531  here. Line 2099  here.
2099  The two additional arguments provide workspace for the function. The workspace  The two additional arguments provide workspace for the function. The workspace
2100  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
2101  multiple paths through the pattern tree. More workspace will be needed for  multiple paths through the pattern tree. More workspace will be needed for
2102  patterns and subjects where there are a lot of possible matches.  patterns and subjects where there are a lot of potential matches.
2103  .P  .P
2104  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:
2105  .sp  .sp
# Line 1554  Here is an example of a simple call to \ Line 2122  Here is an example of a simple call to \
2122  .rs  .rs
2123  .sp  .sp
2124  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
2125  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,
2126  PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
2127  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,
2128  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.
2129  .sp  All but the last four of these are exactly the same as for \fBpcre_exec()\fP,
2130    PCRE_PARTIAL  so their description is not repeated here.
2131  .sp  .sp
2132  This has the same general effect as it does for \fBpcre_exec()\fP, but the    PCRE_PARTIAL_HARD
2133  details are slightly different. When PCRE_PARTIAL is set for    PCRE_PARTIAL_SOFT
2134  \fBpcre_dfa_exec()\fP, the return code PCRE_ERROR_NOMATCH is converted into  .sp
2135  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
2136  complete matches, but there is still at least one matching possibility. The  details are slightly different. When PCRE_PARTIAL_HARD is set for
2137  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
2138  matching string.  is reached and there is still at least one matching possibility that requires
2139    additional characters. This happens even if some complete matches have also
2140    been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
2141    is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached,
2142    there have been no complete matches, but there is still at least one matching
2143    possibility. The portion of the string that was inspected when the longest
2144    partial match was found is set as the first matching string in both cases.
2145    There is a more detailed discussion of partial and multi-segment matching, with
2146    examples, in the
2147    .\" HREF
2148    \fBpcrepartial\fP
2149    .\"
2150    documentation.
2151  .sp  .sp
2152    PCRE_DFA_SHORTEST    PCRE_DFA_SHORTEST
2153  .sp  .sp
2154  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
2155  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
2156  this is necessarily the shortest possible match at the first possible matching  works, this is necessarily the shortest possible match at the first possible
2157  point in the subject string.  matching point in the subject string.
2158  .sp  .sp
2159    PCRE_DFA_RESTART    PCRE_DFA_RESTART
2160  .sp  .sp
2161  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
2162  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
2163  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
2164  option requests this action; when it is set, the \fIworkspace\fP and  \fIworkspace\fP and \fIwscount\fP options must reference the same vector as
2165  \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
2166  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  
2167  .\" HREF  .\" HREF
2168  \fBpcrepartial\fP  \fBpcrepartial\fP
2169  .\"  .\"
# Line 1613  the three matched strings are Line 2192  the three matched strings are
2192  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
2193  the number of matched substrings. The substrings themselves are returned in  the number of matched substrings. The substrings themselves are returned in
2194  \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
2195  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
2196  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,
2197  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
2198  data, even though the meaning of the strings is different.)  returns data, even though the meaning of the strings is different.)
2199  .P  .P
2200  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
2201  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 2222  that it does not support, for instance,
2222  .sp  .sp
2223    PCRE_ERROR_DFA_UCOND      (-17)    PCRE_ERROR_DFA_UCOND      (-17)
2224  .sp  .sp
2225  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
2226  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
2227    group. These are not supported.
2228  .sp  .sp
2229    PCRE_ERROR_DFA_UMLIMIT    (-18)    PCRE_ERROR_DFA_UMLIMIT    (-18)
2230  .sp  .sp
# Line 1663  When a recursive subpattern is processed Line 2243  When a recursive subpattern is processed
2243  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This
2244  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
2245  extremely rare, as a vector of size 1000 is used.  extremely rare, as a vector of size 1000 is used.
2246  .P  .
2247  .in 0  .
2248  Last updated: 18 January 2006  .SH "SEE ALSO"
2249  .br  .rs
2250  Copyright (c) 1997-2006 University of Cambridge.  .sp
2251    \fBpcrebuild\fP(3), \fBpcrecallout\fP(3), \fBpcrecpp(3)\fP(3),
2252    \fBpcrematching\fP(3), \fBpcrepartial\fP(3), \fBpcreposix\fP(3),
2253    \fBpcreprecompile\fP(3), \fBpcresample\fP(3), \fBpcrestack\fP(3).
2254    .
2255    .
2256    .SH AUTHOR
2257    .rs
2258    .sp
2259    .nf
2260    Philip Hazel
2261    University Computing Service
2262    Cambridge CB2 3QH, England.
2263    .fi
2264    .
2265    .
2266    .SH REVISION
2267    .rs
2268    .sp
2269    .nf
2270    Last updated: 21 November 2010
2271    Copyright (c) 1997-2010 University of Cambridge.
2272    .fi

Legend:
Removed from v.87  
changed lines
  Added in v.576

  ViewVC Help
Powered by ViewVC 1.1.5