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1 .TH PCREAPI 3
2 .SH NAME
3 PCRE - Perl-compatible regular expressions
4 .SH "PCRE NATIVE API"
5 .rs
6 .sp
7 .B #include <pcre.h>
8 .PP
9 .SM
10 .B pcre *pcre_compile(const char *\fIpattern\fP, int \fIoptions\fP,
11 .ti +5n
12 .B const char **\fIerrptr\fP, int *\fIerroffset\fP,
13 .ti +5n
14 .B const unsigned char *\fItableptr\fP);
15 .PP
16 .B pcre *pcre_compile2(const char *\fIpattern\fP, int \fIoptions\fP,
17 .ti +5n
18 .B int *\fIerrorcodeptr\fP,
19 .ti +5n
20 .B const char **\fIerrptr\fP, int *\fIerroffset\fP,
21 .ti +5n
22 .B const unsigned char *\fItableptr\fP);
23 .PP
24 .B pcre_extra *pcre_study(const pcre *\fIcode\fP, int \fIoptions\fP,
25 .ti +5n
26 .B const char **\fIerrptr\fP);
27 .PP
28 .B int pcre_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
29 .ti +5n
30 .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
31 .ti +5n
32 .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);
33 .PP
34 .B int pcre_dfa_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
35 .ti +5n
36 .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
37 .ti +5n
38 .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP,
39 .ti +5n
40 .B int *\fIworkspace\fP, int \fIwscount\fP);
41 .PP
42 .B int pcre_copy_named_substring(const pcre *\fIcode\fP,
43 .ti +5n
44 .B const char *\fIsubject\fP, int *\fIovector\fP,
45 .ti +5n
46 .B int \fIstringcount\fP, const char *\fIstringname\fP,
47 .ti +5n
48 .B char *\fIbuffer\fP, int \fIbuffersize\fP);
49 .PP
50 .B int pcre_copy_substring(const char *\fIsubject\fP, int *\fIovector\fP,
51 .ti +5n
52 .B int \fIstringcount\fP, int \fIstringnumber\fP, char *\fIbuffer\fP,
53 .ti +5n
54 .B int \fIbuffersize\fP);
55 .PP
56 .B int pcre_get_named_substring(const pcre *\fIcode\fP,
57 .ti +5n
58 .B const char *\fIsubject\fP, int *\fIovector\fP,
59 .ti +5n
60 .B int \fIstringcount\fP, const char *\fIstringname\fP,
61 .ti +5n
62 .B const char **\fIstringptr\fP);
63 .PP
64 .B int pcre_get_stringnumber(const pcre *\fIcode\fP,
65 .ti +5n
66 .B const char *\fIname\fP);
67 .PP
68 .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,
73 .ti +5n
74 .B int \fIstringcount\fP, int \fIstringnumber\fP,
75 .ti +5n
76 .B const char **\fIstringptr\fP);
77 .PP
78 .B int pcre_get_substring_list(const char *\fIsubject\fP,
79 .ti +5n
80 .B int *\fIovector\fP, int \fIstringcount\fP, "const char ***\fIlistptr\fP);"
81 .PP
82 .B void pcre_free_substring(const char *\fIstringptr\fP);
83 .PP
84 .B void pcre_free_substring_list(const char **\fIstringptr\fP);
85 .PP
86 .B const unsigned char *pcre_maketables(void);
87 .PP
88 .B int pcre_fullinfo(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
89 .ti +5n
90 .B int \fIwhat\fP, void *\fIwhere\fP);
91 .PP
92 .B int pcre_info(const pcre *\fIcode\fP, int *\fIoptptr\fP, int
93 .B *\fIfirstcharptr\fP);
94 .PP
95 .B int pcre_refcount(pcre *\fIcode\fP, int \fIadjust\fP);
96 .PP
97 .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);
98 .PP
99 .B char *pcre_version(void);
100 .PP
101 .B void *(*pcre_malloc)(size_t);
102 .PP
103 .B void (*pcre_free)(void *);
104 .PP
105 .B void *(*pcre_stack_malloc)(size_t);
106 .PP
107 .B void (*pcre_stack_free)(void *);
108 .PP
109 .B int (*pcre_callout)(pcre_callout_block *);
110 .
111 .
112 .SH "PCRE API OVERVIEW"
113 .rs
114 .sp
115 PCRE has its own native API, which is described in this document. There are
116 also some wrapper functions that correspond to the POSIX regular expression
117 API. These are described in the
118 .\" HREF
119 \fBpcreposix\fP
120 .\"
121 documentation. Both of these APIs define a set of C function calls. A C++
122 wrapper is distributed with PCRE. It is documented in the
123 .\" HREF
124 \fBpcrecpp\fP
125 .\"
126 page.
127 .P
128 The native API C function prototypes are defined in the header file
129 \fBpcre.h\fP, and on Unix systems the library itself is called \fBlibpcre\fP.
130 It can normally be accessed by adding \fB-lpcre\fP to the command for linking
131 an application that uses PCRE. The header file defines the macros PCRE_MAJOR
132 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.
134 .P
135 The functions \fBpcre_compile()\fP, \fBpcre_compile2()\fP, \fBpcre_study()\fP,
136 and \fBpcre_exec()\fP are used for compiling and matching regular expressions
137 in a Perl-compatible manner. A sample program that demonstrates the simplest
138 way of using them is provided in the file called \fIpcredemo.c\fP in the PCRE
139 source distribution. A listing of this program is given in the
140 .\" HREF
141 \fBpcredemo\fP
142 .\"
143 documentation, and the
144 .\" HREF
145 \fBpcresample\fP
146 .\"
147 documentation describes how to compile and run it.
148 .P
149 A second matching function, \fBpcre_dfa_exec()\fP, which is not
150 Perl-compatible, is also provided. This uses a different algorithm for the
151 matching. The alternative algorithm finds all possible matches (at a given
152 point in the subject), and scans the subject just once (unless there are
153 lookbehind assertions). However, this algorithm does not return captured
154 substrings. A description of the two matching algorithms and their advantages
155 and disadvantages is given in the
156 .\" HREF
157 \fBpcrematching\fP
158 .\"
159 documentation.
160 .P
161 In addition to the main compiling and matching functions, there are convenience
162 functions for extracting captured substrings from a subject string that is
163 matched by \fBpcre_exec()\fP. They are:
164 .sp
165 \fBpcre_copy_substring()\fP
166 \fBpcre_copy_named_substring()\fP
167 \fBpcre_get_substring()\fP
168 \fBpcre_get_named_substring()\fP
169 \fBpcre_get_substring_list()\fP
170 \fBpcre_get_stringnumber()\fP
171 \fBpcre_get_stringtable_entries()\fP
172 .sp
173 \fBpcre_free_substring()\fP and \fBpcre_free_substring_list()\fP are also
174 provided, to free the memory used for extracted strings.
175 .P
176 The function \fBpcre_maketables()\fP is used to build a set of character tables
177 in the current locale for passing to \fBpcre_compile()\fP, \fBpcre_exec()\fP,
178 or \fBpcre_dfa_exec()\fP. This is an optional facility that is provided for
179 specialist use. Most commonly, no special tables are passed, in which case
180 internal tables that are generated when PCRE is built are used.
181 .P
182 The function \fBpcre_fullinfo()\fP is used to find out information about a
183 compiled pattern; \fBpcre_info()\fP is an obsolete version that returns only
184 some of the available information, but is retained for backwards compatibility.
185 The function \fBpcre_version()\fP returns a pointer to a string containing the
186 version of PCRE and its date of release.
187 .P
188 The function \fBpcre_refcount()\fP maintains a reference count in a data block
189 containing a compiled pattern. This is provided for the benefit of
190 object-oriented applications.
191 .P
192 The global variables \fBpcre_malloc\fP and \fBpcre_free\fP initially contain
193 the entry points of the standard \fBmalloc()\fP and \fBfree()\fP functions,
194 respectively. PCRE calls the memory management functions via these variables,
195 so a calling program can replace them if it wishes to intercept the calls. This
196 should be done before calling any PCRE functions.
197 .P
198 The global variables \fBpcre_stack_malloc\fP and \fBpcre_stack_free\fP are also
199 indirections to memory management functions. These special functions are used
200 only when PCRE is compiled to use the heap for remembering data, instead of
201 recursive function calls, when running the \fBpcre_exec()\fP function. See the
202 .\" HREF
203 \fBpcrebuild\fP
204 .\"
205 documentation for details of how to do this. It is a non-standard way of
206 building PCRE, for use in environments that have limited stacks. Because of the
207 greater use of memory management, it runs more slowly. Separate functions are
208 provided so that special-purpose external code can be used for this case. When
209 used, these functions are always called in a stack-like manner (last obtained,
210 first freed), and always for memory blocks of the same size. There is a
211 discussion about PCRE's stack usage in the
212 .\" HREF
213 \fBpcrestack\fP
214 .\"
215 documentation.
216 .P
217 The global variable \fBpcre_callout\fP initially contains NULL. It can be set
218 by the caller to a "callout" function, which PCRE will then call at specified
219 points during a matching operation. Details are given in the
220 .\" HREF
221 \fBpcrecallout\fP
222 .\"
223 documentation.
224 .
225 .
226 .\" HTML <a name="newlines"></a>
227 .SH NEWLINES
228 .rs
229 .sp
230 PCRE supports five different conventions for indicating line breaks in
231 strings: a single CR (carriage return) character, a single LF (linefeed)
232 character, the two-character sequence CRLF, any of the three preceding, or any
233 Unicode newline sequence. The Unicode newline sequences are the three just
234 mentioned, plus the single characters VT (vertical tab, U+000B), FF (formfeed,
235 U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
236 (paragraph separator, U+2029).
237 .P
238 Each of the first three conventions is used by at least one operating system as
239 its standard newline sequence. When PCRE is built, a default can be specified.
240 The default default is LF, which is the Unix standard. When PCRE is run, the
241 default can be overridden, either when a pattern is compiled, or when it is
242 matched.
243 .P
244 At compile time, the newline convention can be specified by the \fIoptions\fP
245 argument of \fBpcre_compile()\fP, or it can be specified by special text at the
246 start of the pattern itself; this overrides any other settings. See the
247 .\" HREF
248 \fBpcrepattern\fP
249 .\"
250 page for details of the special character sequences.
251 .P
252 In the PCRE documentation the word "newline" is used to mean "the character or
253 pair of characters that indicate a line break". The choice of newline
254 convention affects the handling of the dot, circumflex, and dollar
255 metacharacters, the handling of #-comments in /x mode, and, when CRLF is a
256 recognized line ending sequence, the match position advancement for a
257 non-anchored pattern. There is more detail about this in the
258 .\" HTML <a href="#execoptions">
259 .\" </a>
260 section on \fBpcre_exec()\fP options
261 .\"
262 below.
263 .P
264 The choice of newline convention does not affect the interpretation of
265 the \en or \er escape sequences, nor does it affect what \eR matches, which is
266 controlled in a similar way, but by separate options.
267 .
268 .
269 .SH MULTITHREADING
270 .rs
271 .sp
272 The PCRE functions can be used in multi-threading applications, with the
273 proviso that the memory management functions pointed to by \fBpcre_malloc\fP,
274 \fBpcre_free\fP, \fBpcre_stack_malloc\fP, and \fBpcre_stack_free\fP, and the
275 callout function pointed to by \fBpcre_callout\fP, are shared by all threads.
276 .P
277 The compiled form of a regular expression is not altered during matching, so
278 the same compiled pattern can safely be used by several threads at once.
279 .
280 .
281 .SH "SAVING PRECOMPILED PATTERNS FOR LATER USE"
282 .rs
283 .sp
284 The compiled form of a regular expression can be saved and re-used at a later
285 time, possibly by a different program, and even on a host other than the one on
286 which it was compiled. Details are given in the
287 .\" HREF
288 \fBpcreprecompile\fP
289 .\"
290 documentation. However, compiling a regular expression with one version of PCRE
291 for use with a different version is not guaranteed to work and may cause
292 crashes.
293 .
294 .
295 .SH "CHECKING BUILD-TIME OPTIONS"
296 .rs
297 .sp
298 .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);
299 .PP
300 The function \fBpcre_config()\fP makes it possible for a PCRE client to
301 discover which optional features have been compiled into the PCRE library. The
302 .\" HREF
303 \fBpcrebuild\fP
304 .\"
305 documentation has more details about these optional features.
306 .P
307 The first argument for \fBpcre_config()\fP is an integer, specifying which
308 information is required; the second argument is a pointer to a variable into
309 which the information is placed. The following information is available:
310 .sp
311 PCRE_CONFIG_UTF8
312 .sp
313 The output is an integer that is set to one if UTF-8 support is available;
314 otherwise it is set to zero.
315 .sp
316 PCRE_CONFIG_UNICODE_PROPERTIES
317 .sp
318 The output is an integer that is set to one if support for Unicode character
319 properties is available; otherwise it is set to zero.
320 .sp
321 PCRE_CONFIG_NEWLINE
322 .sp
323 The output is an integer whose value specifies the default character sequence
324 that is recognized as meaning "newline". The four values that are supported
325 are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF, and -1 for ANY.
326 Though they are derived from ASCII, the same values are returned in EBCDIC
327 environments. The default should normally correspond to the standard sequence
328 for your operating system.
329 .sp
330 PCRE_CONFIG_BSR
331 .sp
332 The output is an integer whose value indicates what character sequences the \eR
333 escape sequence matches by default. A value of 0 means that \eR matches any
334 Unicode line ending sequence; a value of 1 means that \eR matches only CR, LF,
335 or CRLF. The default can be overridden when a pattern is compiled or matched.
336 .sp
337 PCRE_CONFIG_LINK_SIZE
338 .sp
339 The output is an integer that contains the number of bytes used for internal
340 linkage in compiled regular expressions. The value is 2, 3, or 4. Larger values
341 allow larger regular expressions to be compiled, at the expense of slower
342 matching. The default value of 2 is sufficient for all but the most massive
343 patterns, since it allows the compiled pattern to be up to 64K in size.
344 .sp
345 PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
346 .sp
347 The output is an integer that contains the threshold above which the POSIX
348 interface uses \fBmalloc()\fP for output vectors. Further details are given in
349 the
350 .\" HREF
351 \fBpcreposix\fP
352 .\"
353 documentation.
354 .sp
355 PCRE_CONFIG_MATCH_LIMIT
356 .sp
357 The output is a long integer that gives the default limit for the number of
358 internal matching function calls in a \fBpcre_exec()\fP execution. Further
359 details are given with \fBpcre_exec()\fP below.
360 .sp
361 PCRE_CONFIG_MATCH_LIMIT_RECURSION
362 .sp
363 The output is a long integer that gives the default limit for the depth of
364 recursion when calling the internal matching function in a \fBpcre_exec()\fP
365 execution. Further details are given with \fBpcre_exec()\fP below.
366 .sp
367 PCRE_CONFIG_STACKRECURSE
368 .sp
369 The output is an integer that is set to one if internal recursion when running
370 \fBpcre_exec()\fP is implemented by recursive function calls that use the stack
371 to remember their state. This is the usual way that PCRE is compiled. The
372 output is zero if PCRE was compiled to use blocks of data on the heap instead
373 of recursive function calls. In this case, \fBpcre_stack_malloc\fP and
374 \fBpcre_stack_free\fP are called to manage memory blocks on the heap, thus
375 avoiding the use of the stack.
376 .
377 .
378 .SH "COMPILING A PATTERN"
379 .rs
380 .sp
381 .B pcre *pcre_compile(const char *\fIpattern\fP, int \fIoptions\fP,
382 .ti +5n
383 .B const char **\fIerrptr\fP, int *\fIerroffset\fP,
384 .ti +5n
385 .B const unsigned char *\fItableptr\fP);
386 .sp
387 .B pcre *pcre_compile2(const char *\fIpattern\fP, int \fIoptions\fP,
388 .ti +5n
389 .B int *\fIerrorcodeptr\fP,
390 .ti +5n
391 .B const char **\fIerrptr\fP, int *\fIerroffset\fP,
392 .ti +5n
393 .B const unsigned char *\fItableptr\fP);
394 .P
395 Either of the functions \fBpcre_compile()\fP or \fBpcre_compile2()\fP can be
396 called to compile a pattern into an internal form. The only difference between
397 the two interfaces is that \fBpcre_compile2()\fP has an additional argument,
398 \fIerrorcodeptr\fP, via which a numerical error code can be returned. To avoid
399 too much repetition, we refer just to \fBpcre_compile()\fP below, but the
400 information applies equally to \fBpcre_compile2()\fP.
401 .P
402 The pattern is a C string terminated by a binary zero, and is passed in the
403 \fIpattern\fP argument. A pointer to a single block of memory that is obtained
404 via \fBpcre_malloc\fP is returned. This contains the compiled code and related
405 data. The \fBpcre\fP type is defined for the returned block; this is a typedef
406 for a structure whose contents are not externally defined. It is up to the
407 caller to free the memory (via \fBpcre_free\fP) when it is no longer required.
408 .P
409 Although the compiled code of a PCRE regex is relocatable, that is, it does not
410 depend on memory location, the complete \fBpcre\fP data block is not
411 fully relocatable, because it may contain a copy of the \fItableptr\fP
412 argument, which is an address (see below).
413 .P
414 The \fIoptions\fP argument contains various bit settings that affect the
415 compilation. It should be zero if no options are required. The available
416 options are described below. Some of them (in particular, those that are
417 compatible with Perl, but some others as well) can also be set and unset from
418 within the pattern (see the detailed description in the
419 .\" HREF
420 \fBpcrepattern\fP
421 .\"
422 documentation). For those options that can be different in different parts of
423 the pattern, the contents of the \fIoptions\fP argument specifies their
424 settings at the start of compilation and execution. The PCRE_ANCHORED,
425 PCRE_BSR_\fIxxx\fP, and PCRE_NEWLINE_\fIxxx\fP options can be set at the time
426 of matching as well as at compile time.
427 .P
428 If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
429 Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
430 NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual
431 error message. This is a static string that is part of the library. You must
432 not try to free it. The byte offset from the start of the pattern to the
433 character that was being processed when the error was discovered is placed in
434 the variable pointed to by \fIerroffset\fP, which must not be NULL. If it is,
435 an immediate error is given. Some errors are not detected until checks are
436 carried out when the whole pattern has been scanned; in this case the offset is
437 set to the end of the pattern.
438 .P
439 If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the
440 \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is
441 returned via this argument in the event of an error. This is in addition to the
442 textual error message. Error codes and messages are listed below.
443 .P
444 If the final argument, \fItableptr\fP, is NULL, PCRE uses a default set of
445 character tables that are built when PCRE is compiled, using the default C
446 locale. Otherwise, \fItableptr\fP must be an address that is the result of a
447 call to \fBpcre_maketables()\fP. This value is stored with the compiled
448 pattern, and used again by \fBpcre_exec()\fP, unless another table pointer is
449 passed to it. For more discussion, see the section on locale support below.
450 .P
451 This code fragment shows a typical straightforward call to \fBpcre_compile()\fP:
452 .sp
453 pcre *re;
454 const char *error;
455 int erroffset;
456 re = pcre_compile(
457 "^A.*Z", /* the pattern */
458 0, /* default options */
459 &error, /* for error message */
460 &erroffset, /* for error offset */
461 NULL); /* use default character tables */
462 .sp
463 The following names for option bits are defined in the \fBpcre.h\fP header
464 file:
465 .sp
466 PCRE_ANCHORED
467 .sp
468 If this bit is set, the pattern is forced to be "anchored", that is, it is
469 constrained to match only at the first matching point in the string that is
470 being searched (the "subject string"). This effect can also be achieved by
471 appropriate constructs in the pattern itself, which is the only way to do it in
472 Perl.
473 .sp
474 PCRE_AUTO_CALLOUT
475 .sp
476 If this bit is set, \fBpcre_compile()\fP automatically inserts callout items,
477 all with number 255, before each pattern item. For discussion of the callout
478 facility, see the
479 .\" HREF
480 \fBpcrecallout\fP
481 .\"
482 documentation.
483 .sp
484 PCRE_BSR_ANYCRLF
485 PCRE_BSR_UNICODE
486 .sp
487 These options (which are mutually exclusive) control what the \eR escape
488 sequence matches. The choice is either to match only CR, LF, or CRLF, or to
489 match any Unicode newline sequence. The default is specified when PCRE is
490 built. It can be overridden from within the pattern, or by setting an option
491 when a compiled pattern is matched.
492 .sp
493 PCRE_CASELESS
494 .sp
495 If this bit is set, letters in the pattern match both upper and lower case
496 letters. It is equivalent to Perl's /i option, and it can be changed within a
497 pattern by a (?i) option setting. In UTF-8 mode, PCRE always understands the
498 concept of case for characters whose values are less than 128, so caseless
499 matching is always possible. For characters with higher values, the concept of
500 case is supported if PCRE is compiled with Unicode property support, but not
501 otherwise. If you want to use caseless matching for characters 128 and above,
502 you must ensure that PCRE is compiled with Unicode property support as well as
503 with UTF-8 support.
504 .sp
505 PCRE_DOLLAR_ENDONLY
506 .sp
507 If this bit is set, a dollar metacharacter in the pattern matches only at the
508 end of the subject string. Without this option, a dollar also matches
509 immediately before a newline at the end of the string (but not before any other
510 newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is set.
511 There is no equivalent to this option in Perl, and no way to set it within a
512 pattern.
513 .sp
514 PCRE_DOTALL
515 .sp
516 If this bit is set, a dot metacharater in the pattern matches all characters,
517 including those that indicate newline. Without it, a dot does not match when
518 the current position is at a newline. This option is equivalent to Perl's /s
519 option, and it can be changed within a pattern by a (?s) option setting. A
520 negative class such as [^a] always matches newline characters, independent of
521 the setting of this option.
522 .sp
523 PCRE_DUPNAMES
524 .sp
525 If this bit is set, names used to identify capturing subpatterns need not be
526 unique. This can be helpful for certain types of pattern when it is known that
527 only one instance of the named subpattern can ever be matched. There are more
528 details of named subpatterns below; see also the
529 .\" HREF
530 \fBpcrepattern\fP
531 .\"
532 documentation.
533 .sp
534 PCRE_EXTENDED
535 .sp
536 If this bit is set, whitespace data characters in the pattern are totally
537 ignored except when escaped or inside a character class. Whitespace does not
538 include the VT character (code 11). In addition, characters between an
539 unescaped # outside a character class and the next newline, inclusive, are also
540 ignored. This is equivalent to Perl's /x option, and it can be changed within a
541 pattern by a (?x) option setting.
542 .P
543 This option makes it possible to include comments inside complicated patterns.
544 Note, however, that this applies only to data characters. Whitespace characters
545 may never appear within special character sequences in a pattern, for example
546 within the sequence (?( which introduces a conditional subpattern.
547 .sp
548 PCRE_EXTRA
549 .sp
550 This option was invented in order to turn on additional functionality of PCRE
551 that is incompatible with Perl, but it is currently of very little use. When
552 set, any backslash in a pattern that is followed by a letter that has no
553 special meaning causes an error, thus reserving these combinations for future
554 expansion. By default, as in Perl, a backslash followed by a letter with no
555 special meaning is treated as a literal. (Perl can, however, be persuaded to
556 give a warning for this.) There are at present no other features controlled by
557 this option. It can also be set by a (?X) option setting within a pattern.
558 .sp
559 PCRE_FIRSTLINE
560 .sp
561 If this option is set, an unanchored pattern is required to match before or at
562 the first newline in the subject string, though the matched text may continue
563 over the newline.
564 .sp
565 PCRE_JAVASCRIPT_COMPAT
566 .sp
567 If this option is set, PCRE's behaviour is changed in some ways so that it is
568 compatible with JavaScript rather than Perl. The changes are as follows:
569 .P
570 (1) A lone closing square bracket in a pattern causes a compile-time error,
571 because this is illegal in JavaScript (by default it is treated as a data
572 character). Thus, the pattern AB]CD becomes illegal when this option is set.
573 .P
574 (2) At run time, a back reference to an unset subpattern group matches an empty
575 string (by default this causes the current matching alternative to fail). A
576 pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
577 an "a" in the subject), whereas it fails by default, for Perl compatibility.
578 .sp
579 PCRE_MULTILINE
580 .sp
581 By default, PCRE treats the subject string as consisting of a single line of
582 characters (even if it actually contains newlines). The "start of line"
583 metacharacter (^) matches only at the start of the string, while the "end of
584 line" metacharacter ($) matches only at the end of the string, or before a
585 terminating newline (unless PCRE_DOLLAR_ENDONLY is set). This is the same as
586 Perl.
587 .P
588 When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs
589 match immediately following or immediately before internal newlines in the
590 subject string, respectively, as well as at the very start and end. This is
591 equivalent to Perl's /m option, and it can be changed within a pattern by a
592 (?m) option setting. If there are no newlines in a subject string, or no
593 occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect.
594 .sp
595 PCRE_NEWLINE_CR
596 PCRE_NEWLINE_LF
597 PCRE_NEWLINE_CRLF
598 PCRE_NEWLINE_ANYCRLF
599 PCRE_NEWLINE_ANY
600 .sp
601 These options override the default newline definition that was chosen when PCRE
602 was built. Setting the first or the second specifies that a newline is
603 indicated by a single character (CR or LF, respectively). Setting
604 PCRE_NEWLINE_CRLF specifies that a newline is indicated by the two-character
605 CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three
606 preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
607 that any Unicode newline sequence should be recognized. The Unicode newline
608 sequences are the three just mentioned, plus the single characters VT (vertical
609 tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line
610 separator, U+2028), and PS (paragraph separator, U+2029). The last two are
611 recognized only in UTF-8 mode.
612 .P
613 The newline setting in the options word uses three bits that are treated
614 as a number, giving eight possibilities. Currently only six are used (default
615 plus the five values above). This means that if you set more than one newline
616 option, the combination may or may not be sensible. For example,
617 PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but
618 other combinations may yield unused numbers and cause an error.
619 .P
620 The only time that a line break is specially recognized when compiling a
621 pattern is if PCRE_EXTENDED is set, and an unescaped # outside a character
622 class is encountered. This indicates a comment that lasts until after the next
623 line break sequence. In other circumstances, line break sequences are treated
624 as literal data, except that in PCRE_EXTENDED mode, both CR and LF are treated
625 as whitespace characters and are therefore ignored.
626 .P
627 The newline option that is set at compile time becomes the default that is used
628 for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.
629 .sp
630 PCRE_NO_AUTO_CAPTURE
631 .sp
632 If this option is set, it disables the use of numbered capturing parentheses in
633 the pattern. Any opening parenthesis that is not followed by ? behaves as if it
634 were followed by ?: but named parentheses can still be used for capturing (and
635 they acquire numbers in the usual way). There is no equivalent of this option
636 in Perl.
637 .sp
638 PCRE_UNGREEDY
639 .sp
640 This option inverts the "greediness" of the quantifiers so that they are not
641 greedy by default, but become greedy if followed by "?". It is not compatible
642 with Perl. It can also be set by a (?U) option setting within the pattern.
643 .sp
644 PCRE_UTF8
645 .sp
646 This option causes PCRE to regard both the pattern and the subject as strings
647 of UTF-8 characters instead of single-byte character strings. However, it is
648 available only when PCRE is built to include UTF-8 support. If not, the use
649 of this option provokes an error. Details of how this option changes the
650 behaviour of PCRE are given in the
651 .\" HTML <a href="pcre.html#utf8support">
652 .\" </a>
653 section on UTF-8 support
654 .\"
655 in the main
656 .\" HREF
657 \fBpcre\fP
658 .\"
659 page.
660 .sp
661 PCRE_NO_UTF8_CHECK
662 .sp
663 When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
664 automatically checked. There is a discussion about the
665 .\" HTML <a href="pcre.html#utf8strings">
666 .\" </a>
667 validity of UTF-8 strings
668 .\"
669 in the main
670 .\" HREF
671 \fBpcre\fP
672 .\"
673 page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_compile()\fP
674 returns an error. If you already know that your pattern is valid, and you want
675 to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
676 option. When it is set, the effect of passing an invalid UTF-8 string as a
677 pattern is undefined. It may cause your program to crash. Note that this option
678 can also be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress
679 the UTF-8 validity checking of subject strings.
680 .
681 .
682 .SH "COMPILATION ERROR CODES"
683 .rs
684 .sp
685 The following table lists the error codes than may be returned by
686 \fBpcre_compile2()\fP, along with the error messages that may be returned by
687 both compiling functions. As PCRE has developed, some error codes have fallen
688 out of use. To avoid confusion, they have not been re-used.
689 .sp
690 0 no error
691 1 \e at end of pattern
692 2 \ec at end of pattern
693 3 unrecognized character follows \e
694 4 numbers out of order in {} quantifier
695 5 number too big in {} quantifier
696 6 missing terminating ] for character class
697 7 invalid escape sequence in character class
698 8 range out of order in character class
699 9 nothing to repeat
700 10 [this code is not in use]
701 11 internal error: unexpected repeat
702 12 unrecognized character after (? or (?-
703 13 POSIX named classes are supported only within a class
704 14 missing )
705 15 reference to non-existent subpattern
706 16 erroffset passed as NULL
707 17 unknown option bit(s) set
708 18 missing ) after comment
709 19 [this code is not in use]
710 20 regular expression is too large
711 21 failed to get memory
712 22 unmatched parentheses
713 23 internal error: code overflow
714 24 unrecognized character after (?<
715 25 lookbehind assertion is not fixed length
716 26 malformed number or name after (?(
717 27 conditional group contains more than two branches
718 28 assertion expected after (?(
719 29 (?R or (?[+-]digits must be followed by )
720 30 unknown POSIX class name
721 31 POSIX collating elements are not supported
722 32 this version of PCRE is not compiled with PCRE_UTF8 support
723 33 [this code is not in use]
724 34 character value in \ex{...} sequence is too large
725 35 invalid condition (?(0)
726 36 \eC not allowed in lookbehind assertion
727 37 PCRE does not support \eL, \el, \eN, \eU, or \eu
728 38 number after (?C is > 255
729 39 closing ) for (?C expected
730 40 recursive call could loop indefinitely
731 41 unrecognized character after (?P
732 42 syntax error in subpattern name (missing terminator)
733 43 two named subpatterns have the same name
734 44 invalid UTF-8 string
735 45 support for \eP, \ep, and \eX has not been compiled
736 46 malformed \eP or \ep sequence
737 47 unknown property name after \eP or \ep
738 48 subpattern name is too long (maximum 32 characters)
739 49 too many named subpatterns (maximum 10000)
740 50 [this code is not in use]
741 51 octal value is greater than \e377 (not in UTF-8 mode)
742 52 internal error: overran compiling workspace
743 53 internal error: previously-checked referenced subpattern not found
744 54 DEFINE group contains more than one branch
745 55 repeating a DEFINE group is not allowed
746 56 inconsistent NEWLINE options
747 57 \eg is not followed by a braced, angle-bracketed, or quoted
748 name/number or by a plain number
749 58 a numbered reference must not be zero
750 59 (*VERB) with an argument is not supported
751 60 (*VERB) not recognized
752 61 number is too big
753 62 subpattern name expected
754 63 digit expected after (?+
755 64 ] is an invalid data character in JavaScript compatibility mode
756 .sp
757 The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
758 be used if the limits were changed when PCRE was built.
759 .
760 .
761 .SH "STUDYING A PATTERN"
762 .rs
763 .sp
764 .B pcre_extra *pcre_study(const pcre *\fIcode\fP, int \fIoptions\fP
765 .ti +5n
766 .B const char **\fIerrptr\fP);
767 .PP
768 If a compiled pattern is going to be used several times, it is worth spending
769 more time analyzing it in order to speed up the time taken for matching. The
770 function \fBpcre_study()\fP takes a pointer to a compiled pattern as its first
771 argument. If studying the pattern produces additional information that will
772 help speed up matching, \fBpcre_study()\fP returns a pointer to a
773 \fBpcre_extra\fP block, in which the \fIstudy_data\fP field points to the
774 results of the study.
775 .P
776 The returned value from \fBpcre_study()\fP can be passed directly to
777 \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. However, a \fBpcre_extra\fP block
778 also contains other fields that can be set by the caller before the block is
779 passed; these are described
780 .\" HTML <a href="#extradata">
781 .\" </a>
782 below
783 .\"
784 in the section on matching a pattern.
785 .P
786 If studying the pattern does not produce any useful information,
787 \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program
788 wants to pass any of the other fields to \fBpcre_exec()\fP or
789 \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.
790 .P
791 The second argument of \fBpcre_study()\fP contains option bits. At present, no
792 options are defined, and this argument should always be zero.
793 .P
794 The third argument for \fBpcre_study()\fP is a pointer for an error message. If
795 studying succeeds (even if no data is returned), the variable it points to is
796 set to NULL. Otherwise it is set to point to a textual error message. This is a
797 static string that is part of the library. You must not try to free it. You
798 should test the error pointer for NULL after calling \fBpcre_study()\fP, to be
799 sure that it has run successfully.
800 .P
801 This is a typical call to \fBpcre_study\fP():
802 .sp
803 pcre_extra *pe;
804 pe = pcre_study(
805 re, /* result of pcre_compile() */
806 0, /* no options exist */
807 &error); /* set to NULL or points to a message */
808 .sp
809 Studying a pattern does two things: first, a lower bound for the length of
810 subject string that is needed to match the pattern is computed. This does not
811 mean that there are any strings of that length that match, but it does
812 guarantee that no shorter strings match. The value is used by
813 \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP to avoid wasting time by trying to
814 match strings that are shorter than the lower bound. You can find out the value
815 in a calling program via the \fBpcre_fullinfo()\fP function.
816 .P
817 Studying a pattern is also useful for non-anchored patterns that do not have a
818 single fixed starting character. A bitmap of possible starting bytes is
819 created. This speeds up finding a position in the subject at which to start
820 matching.
821 .
822 .
823 .\" HTML <a name="localesupport"></a>
824 .SH "LOCALE SUPPORT"
825 .rs
826 .sp
827 PCRE handles caseless matching, and determines whether characters are letters,
828 digits, or whatever, by reference to a set of tables, indexed by character
829 value. When running in UTF-8 mode, this applies only to characters with codes
830 less than 128. Higher-valued codes never match escapes such as \ew or \ed, but
831 can be tested with \ep if PCRE is built with Unicode character property
832 support. The use of locales with Unicode is discouraged. If you are handling
833 characters with codes greater than 128, you should either use UTF-8 and
834 Unicode, or use locales, but not try to mix the two.
835 .P
836 PCRE contains an internal set of tables that are used when the final argument
837 of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.
838 Normally, the internal tables recognize only ASCII characters. However, when
839 PCRE is built, it is possible to cause the internal tables to be rebuilt in the
840 default "C" locale of the local system, which may cause them to be different.
841 .P
842 The internal tables can always be overridden by tables supplied by the
843 application that calls PCRE. These may be created in a different locale from
844 the default. As more and more applications change to using Unicode, the need
845 for this locale support is expected to die away.
846 .P
847 External tables are built by calling the \fBpcre_maketables()\fP function,
848 which has no arguments, in the relevant locale. The result can then be passed
849 to \fBpcre_compile()\fP or \fBpcre_exec()\fP as often as necessary. For
850 example, to build and use tables that are appropriate for the French locale
851 (where accented characters with values greater than 128 are treated as letters),
852 the following code could be used:
853 .sp
854 setlocale(LC_CTYPE, "fr_FR");
855 tables = pcre_maketables();
856 re = pcre_compile(..., tables);
857 .sp
858 The locale name "fr_FR" is used on Linux and other Unix-like systems; if you
859 are using Windows, the name for the French locale is "french".
860 .P
861 When \fBpcre_maketables()\fP runs, the tables are built in memory that is
862 obtained via \fBpcre_malloc\fP. It is the caller's responsibility to ensure
863 that the memory containing the tables remains available for as long as it is
864 needed.
865 .P
866 The pointer that is passed to \fBpcre_compile()\fP is saved with the compiled
867 pattern, and the same tables are used via this pointer by \fBpcre_study()\fP
868 and normally also by \fBpcre_exec()\fP. Thus, by default, for any single
869 pattern, compilation, studying and matching all happen in the same locale, but
870 different patterns can be compiled in different locales.
871 .P
872 It is possible to pass a table pointer or NULL (indicating the use of the
873 internal tables) to \fBpcre_exec()\fP. Although not intended for this purpose,
874 this facility could be used to match a pattern in a different locale from the
875 one in which it was compiled. Passing table pointers at run time is discussed
876 below in the section on matching a pattern.
877 .
878 .
879 .SH "INFORMATION ABOUT A PATTERN"
880 .rs
881 .sp
882 .B int pcre_fullinfo(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
883 .ti +5n
884 .B int \fIwhat\fP, void *\fIwhere\fP);
885 .PP
886 The \fBpcre_fullinfo()\fP function returns information about a compiled
887 pattern. It replaces the obsolete \fBpcre_info()\fP function, which is
888 nevertheless retained for backwards compability (and is documented below).
889 .P
890 The first argument for \fBpcre_fullinfo()\fP is a pointer to the compiled
891 pattern. The second argument is the result of \fBpcre_study()\fP, or NULL if
892 the pattern was not studied. The third argument specifies which piece of
893 information is required, and the fourth argument is a pointer to a variable
894 to receive the data. The yield of the function is zero for success, or one of
895 the following negative numbers:
896 .sp
897 PCRE_ERROR_NULL the argument \fIcode\fP was NULL
898 the argument \fIwhere\fP was NULL
899 PCRE_ERROR_BADMAGIC the "magic number" was not found
900 PCRE_ERROR_BADOPTION the value of \fIwhat\fP was invalid
901 .sp
902 The "magic number" is placed at the start of each compiled pattern as an simple
903 check against passing an arbitrary memory pointer. Here is a typical call of
904 \fBpcre_fullinfo()\fP, to obtain the length of the compiled pattern:
905 .sp
906 int rc;
907 size_t length;
908 rc = pcre_fullinfo(
909 re, /* result of pcre_compile() */
910 pe, /* result of pcre_study(), or NULL */
911 PCRE_INFO_SIZE, /* what is required */
912 &length); /* where to put the data */
913 .sp
914 The possible values for the third argument are defined in \fBpcre.h\fP, and are
915 as follows:
916 .sp
917 PCRE_INFO_BACKREFMAX
918 .sp
919 Return the number of the highest back reference in the pattern. The fourth
920 argument should point to an \fBint\fP variable. Zero is returned if there are
921 no back references.
922 .sp
923 PCRE_INFO_CAPTURECOUNT
924 .sp
925 Return the number of capturing subpatterns in the pattern. The fourth argument
926 should point to an \fBint\fP variable.
927 .sp
928 PCRE_INFO_DEFAULT_TABLES
929 .sp
930 Return a pointer to the internal default character tables within PCRE. The
931 fourth argument should point to an \fBunsigned char *\fP variable. This
932 information call is provided for internal use by the \fBpcre_study()\fP
933 function. External callers can cause PCRE to use its internal tables by passing
934 a NULL table pointer.
935 .sp
936 PCRE_INFO_FIRSTBYTE
937 .sp
938 Return information about the first byte of any matched string, for a
939 non-anchored pattern. The fourth argument should point to an \fBint\fP
940 variable. (This option used to be called PCRE_INFO_FIRSTCHAR; the old name is
941 still recognized for backwards compatibility.)
942 .P
943 If there is a fixed first byte, for example, from a pattern such as
944 (cat|cow|coyote), its value is returned. Otherwise, if either
945 .sp
946 (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
947 starts with "^", or
948 .sp
949 (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set
950 (if it were set, the pattern would be anchored),
951 .sp
952 -1 is returned, indicating that the pattern matches only at the start of a
953 subject string or after any newline within the string. Otherwise -2 is
954 returned. For anchored patterns, -2 is returned.
955 .sp
956 PCRE_INFO_FIRSTTABLE
957 .sp
958 If the pattern was studied, and this resulted in the construction of a 256-bit
959 table indicating a fixed set of bytes for the first byte in any matching
960 string, a pointer to the table is returned. Otherwise NULL is returned. The
961 fourth argument should point to an \fBunsigned char *\fP variable.
962 .sp
963 PCRE_INFO_HASCRORLF
964 .sp
965 Return 1 if the pattern contains any explicit matches for CR or LF characters,
966 otherwise 0. The fourth argument should point to an \fBint\fP variable. An
967 explicit match is either a literal CR or LF character, or \er or \en.
968 .sp
969 PCRE_INFO_JCHANGED
970 .sp
971 Return 1 if the (?J) or (?-J) option setting is used in the pattern, otherwise
972 0. The fourth argument should point to an \fBint\fP variable. (?J) and
973 (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
974 .sp
975 PCRE_INFO_LASTLITERAL
976 .sp
977 Return the value of the rightmost literal byte that must exist in any matched
978 string, other than at its start, if such a byte has been recorded. The fourth
979 argument should point to an \fBint\fP variable. If there is no such byte, -1 is
980 returned. For anchored patterns, a last literal byte is recorded only if it
981 follows something of variable length. For example, for the pattern
982 /^a\ed+z\ed+/ the returned value is "z", but for /^a\edz\ed/ the returned value
983 is -1.
984 .sp
985 PCRE_INFO_MINLENGTH
986 .sp
987 If the pattern was studied and a minimum length for matching subject strings
988 was computed, its value is returned. Otherwise the returned value is -1. The
989 value is a number of characters, not bytes (this may be relevant in UTF-8
990 mode). The fourth argument should point to an \fBint\fP variable. A
991 non-negative value is a lower bound to the length of any matching string. There
992 may not be any strings of that length that do actually match, but every string
993 that does match is at least that long.
994 .sp
995 PCRE_INFO_NAMECOUNT
996 PCRE_INFO_NAMEENTRYSIZE
997 PCRE_INFO_NAMETABLE
998 .sp
999 PCRE supports the use of named as well as numbered capturing parentheses. The
1000 names are just an additional way of identifying the parentheses, which still
1001 acquire numbers. Several convenience functions such as
1002 \fBpcre_get_named_substring()\fP are provided for extracting captured
1003 substrings by name. It is also possible to extract the data directly, by first
1004 converting the name to a number in order to access the correct pointers in the
1005 output vector (described with \fBpcre_exec()\fP below). To do the conversion,
1006 you need to use the name-to-number map, which is described by these three
1007 values.
1008 .P
1009 The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT gives
1010 the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each
1011 entry; both of these return an \fBint\fP value. The entry size depends on the
1012 length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first
1013 entry of the table (a pointer to \fBchar\fP). The first two bytes of each entry
1014 are the number of the capturing parenthesis, most significant byte first. The
1015 rest of the entry is the corresponding name, zero terminated.
1016 .P
1017 The names are in alphabetical order. Duplicate names may appear if (?| is used
1018 to create multiple groups with the same number, as described in the
1019 .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1020 .\" </a>
1021 section on duplicate subpattern numbers
1022 .\"
1023 in the
1024 .\" HREF
1025 \fBpcrepattern\fP
1026 .\"
1027 page. Duplicate names for subpatterns with different numbers are permitted only
1028 if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the
1029 table in the order in which they were found in the pattern. In the absence of
1030 (?| this is the order of increasing number; when (?| is used this is not
1031 necessarily the case because later subpatterns may have lower numbers.
1032 .P
1033 As a simple example of the name/number table, consider the following pattern
1034 (assume PCRE_EXTENDED is set, so white space - including newlines - is
1035 ignored):
1036 .sp
1037 .\" JOIN
1038 (?<date> (?<year>(\ed\ed)?\ed\ed) -
1039 (?<month>\ed\ed) - (?<day>\ed\ed) )
1040 .sp
1041 There are four named subpatterns, so the table has four entries, and each entry
1042 in the table is eight bytes long. The table is as follows, with non-printing
1043 bytes shows in hexadecimal, and undefined bytes shown as ??:
1044 .sp
1045 00 01 d a t e 00 ??
1046 00 05 d a y 00 ?? ??
1047 00 04 m o n t h 00
1048 00 02 y e a r 00 ??
1049 .sp
1050 When writing code to extract data from named subpatterns using the
1051 name-to-number map, remember that the length of the entries is likely to be
1052 different for each compiled pattern.
1053 .sp
1054 PCRE_INFO_OKPARTIAL
1055 .sp
1056 Return 1 if the pattern can be used for partial matching with
1057 \fBpcre_exec()\fP, otherwise 0. The fourth argument should point to an
1058 \fBint\fP variable. From release 8.00, this always returns 1, because the
1059 restrictions that previously applied to partial matching have been lifted. The
1060 .\" HREF
1061 \fBpcrepartial\fP
1062 .\"
1063 documentation gives details of partial matching.
1064 .sp
1065 PCRE_INFO_OPTIONS
1066 .sp
1067 Return a copy of the options with which the pattern was compiled. The fourth
1068 argument should point to an \fBunsigned long int\fP variable. These option bits
1069 are those specified in the call to \fBpcre_compile()\fP, modified by any
1070 top-level option settings at the start of the pattern itself. In other words,
1071 they are the options that will be in force when matching starts. For example,
1072 if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the
1073 result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED.
1074 .P
1075 A pattern is automatically anchored by PCRE if all of its top-level
1076 alternatives begin with one of the following:
1077 .sp
1078 ^ unless PCRE_MULTILINE is set
1079 \eA always
1080 \eG always
1081 .\" JOIN
1082 .* if PCRE_DOTALL is set and there are no back
1083 references to the subpattern in which .* appears
1084 .sp
1085 For such patterns, the PCRE_ANCHORED bit is set in the options returned by
1086 \fBpcre_fullinfo()\fP.
1087 .sp
1088 PCRE_INFO_SIZE
1089 .sp
1090 Return the size of the compiled pattern, that is, the value that was passed as
1091 the argument to \fBpcre_malloc()\fP when PCRE was getting memory in which to
1092 place the compiled data. The fourth argument should point to a \fBsize_t\fP
1093 variable.
1094 .sp
1095 PCRE_INFO_STUDYSIZE
1096 .sp
1097 Return the size of the data block pointed to by the \fIstudy_data\fP field in
1098 a \fBpcre_extra\fP block. That is, it is the value that was passed to
1099 \fBpcre_malloc()\fP when PCRE was getting memory into which to place the data
1100 created by \fBpcre_study()\fP. If \fBpcre_extra\fP is NULL, or there is no
1101 study data, zero is returned. The fourth argument should point to a
1102 \fBsize_t\fP variable.
1103 .
1104 .
1105 .SH "OBSOLETE INFO FUNCTION"
1106 .rs
1107 .sp
1108 .B int pcre_info(const pcre *\fIcode\fP, int *\fIoptptr\fP, int
1109 .B *\fIfirstcharptr\fP);
1110 .PP
1111 The \fBpcre_info()\fP function is now obsolete because its interface is too
1112 restrictive to return all the available data about a compiled pattern. New
1113 programs should use \fBpcre_fullinfo()\fP instead. The yield of
1114 \fBpcre_info()\fP is the number of capturing subpatterns, or one of the
1115 following negative numbers:
1116 .sp
1117 PCRE_ERROR_NULL the argument \fIcode\fP was NULL
1118 PCRE_ERROR_BADMAGIC the "magic number" was not found
1119 .sp
1120 If the \fIoptptr\fP argument is not NULL, a copy of the options with which the
1121 pattern was compiled is placed in the integer it points to (see
1122 PCRE_INFO_OPTIONS above).
1123 .P
1124 If the pattern is not anchored and the \fIfirstcharptr\fP argument is not NULL,
1125 it is used to pass back information about the first character of any matched
1126 string (see PCRE_INFO_FIRSTBYTE above).
1127 .
1128 .
1129 .SH "REFERENCE COUNTS"
1130 .rs
1131 .sp
1132 .B int pcre_refcount(pcre *\fIcode\fP, int \fIadjust\fP);
1133 .PP
1134 The \fBpcre_refcount()\fP function is used to maintain a reference count in the
1135 data block that contains a compiled pattern. It is provided for the benefit of
1136 applications that operate in an object-oriented manner, where different parts
1137 of the application may be using the same compiled pattern, but you want to free
1138 the block when they are all done.
1139 .P
1140 When a pattern is compiled, the reference count field is initialized to zero.
1141 It is changed only by calling this function, whose action is to add the
1142 \fIadjust\fP value (which may be positive or negative) to it. The yield of the
1143 function is the new value. However, the value of the count is constrained to
1144 lie between 0 and 65535, inclusive. If the new value is outside these limits,
1145 it is forced to the appropriate limit value.
1146 .P
1147 Except when it is zero, the reference count is not correctly preserved if a
1148 pattern is compiled on one host and then transferred to a host whose byte-order
1149 is different. (This seems a highly unlikely scenario.)
1150 .
1151 .
1152 .SH "MATCHING A PATTERN: THE TRADITIONAL FUNCTION"
1153 .rs
1154 .sp
1155 .B int pcre_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
1156 .ti +5n
1157 .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
1158 .ti +5n
1159 .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP);
1160 .P
1161 The function \fBpcre_exec()\fP is called to match a subject string against a
1162 compiled pattern, which is passed in the \fIcode\fP argument. If the
1163 pattern was studied, the result of the study should be passed in the
1164 \fIextra\fP argument. This function is the main matching facility of the
1165 library, and it operates in a Perl-like manner. For specialist use there is
1166 also an alternative matching function, which is described
1167 .\" HTML <a href="#dfamatch">
1168 .\" </a>
1169 below
1170 .\"
1171 in the section about the \fBpcre_dfa_exec()\fP function.
1172 .P
1173 In most applications, the pattern will have been compiled (and optionally
1174 studied) in the same process that calls \fBpcre_exec()\fP. However, it is
1175 possible to save compiled patterns and study data, and then use them later
1176 in different processes, possibly even on different hosts. For a discussion
1177 about this, see the
1178 .\" HREF
1179 \fBpcreprecompile\fP
1180 .\"
1181 documentation.
1182 .P
1183 Here is an example of a simple call to \fBpcre_exec()\fP:
1184 .sp
1185 int rc;
1186 int ovector[30];
1187 rc = pcre_exec(
1188 re, /* result of pcre_compile() */
1189 NULL, /* we didn't study the pattern */
1190 "some string", /* the subject string */
1191 11, /* the length of the subject string */
1192 0, /* start at offset 0 in the subject */
1193 0, /* default options */
1194 ovector, /* vector of integers for substring information */
1195 30); /* number of elements (NOT size in bytes) */
1196 .
1197 .\" HTML <a name="extradata"></a>
1198 .SS "Extra data for \fBpcre_exec()\fR"
1199 .rs
1200 .sp
1201 If the \fIextra\fP argument is not NULL, it must point to a \fBpcre_extra\fP
1202 data block. The \fBpcre_study()\fP function returns such a block (when it
1203 doesn't return NULL), but you can also create one for yourself, and pass
1204 additional information in it. The \fBpcre_extra\fP block contains the following
1205 fields (not necessarily in this order):
1206 .sp
1207 unsigned long int \fIflags\fP;
1208 void *\fIstudy_data\fP;
1209 unsigned long int \fImatch_limit\fP;
1210 unsigned long int \fImatch_limit_recursion\fP;
1211 void *\fIcallout_data\fP;
1212 const unsigned char *\fItables\fP;
1213 .sp
1214 The \fIflags\fP field is a bitmap that specifies which of the other fields
1215 are set. The flag bits are:
1216 .sp
1217 PCRE_EXTRA_STUDY_DATA
1218 PCRE_EXTRA_MATCH_LIMIT
1219 PCRE_EXTRA_MATCH_LIMIT_RECURSION
1220 PCRE_EXTRA_CALLOUT_DATA
1221 PCRE_EXTRA_TABLES
1222 .sp
1223 Other flag bits should be set to zero. The \fIstudy_data\fP field is set in the
1224 \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with
1225 the appropriate flag bit. You should not set this yourself, but you may add to
1226 the block by setting the other fields and their corresponding flag bits.
1227 .P
1228 The \fImatch_limit\fP field provides a means of preventing PCRE from using up a
1229 vast amount of resources when running patterns that are not going to match,
1230 but which have a very large number of possibilities in their search trees. The
1231 classic example is a pattern that uses nested unlimited repeats.
1232 .P
1233 Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly
1234 (sometimes recursively). The limit set by \fImatch_limit\fP is imposed on the
1235 number of times this function is called during a match, which has the effect of
1236 limiting the amount of backtracking that can take place. For patterns that are
1237 not anchored, the count restarts from zero for each position in the subject
1238 string.
1239 .P
1240 The default value for the limit can be set when PCRE is built; the default
1241 default is 10 million, which handles all but the most extreme cases. You can
1242 override the default by suppling \fBpcre_exec()\fP with a \fBpcre_extra\fP
1243 block in which \fImatch_limit\fP is set, and PCRE_EXTRA_MATCH_LIMIT is set in
1244 the \fIflags\fP field. If the limit is exceeded, \fBpcre_exec()\fP returns
1245 PCRE_ERROR_MATCHLIMIT.
1246 .P
1247 The \fImatch_limit_recursion\fP field is similar to \fImatch_limit\fP, but
1248 instead of limiting the total number of times that \fBmatch()\fP is called, it
1249 limits the depth of recursion. The recursion depth is a smaller number than the
1250 total number of calls, because not all calls to \fBmatch()\fP are recursive.
1251 This limit is of use only if it is set smaller than \fImatch_limit\fP.
1252 .P
1253 Limiting the recursion depth limits the amount of stack that can be used, or,
1254 when PCRE has been compiled to use memory on the heap instead of the stack, the
1255 amount of heap memory that can be used.
1256 .P
1257 The default value for \fImatch_limit_recursion\fP can be set when PCRE is
1258 built; the default default is the same value as the default for
1259 \fImatch_limit\fP. You can override the default by suppling \fBpcre_exec()\fP
1260 with a \fBpcre_extra\fP block in which \fImatch_limit_recursion\fP is set, and
1261 PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the \fIflags\fP field. If the limit
1262 is exceeded, \fBpcre_exec()\fP returns PCRE_ERROR_RECURSIONLIMIT.
1263 .P
1264 The \fIcallout_data\fP field is used in conjunction with the "callout" feature,
1265 and is described in the
1266 .\" HREF
1267 \fBpcrecallout\fP
1268 .\"
1269 documentation.
1270 .P
1271 The \fItables\fP field is used to pass a character tables pointer to
1272 \fBpcre_exec()\fP; this overrides the value that is stored with the compiled
1273 pattern. A non-NULL value is stored with the compiled pattern only if custom
1274 tables were supplied to \fBpcre_compile()\fP via its \fItableptr\fP argument.
1275 If NULL is passed to \fBpcre_exec()\fP using this mechanism, it forces PCRE's
1276 internal tables to be used. This facility is helpful when re-using patterns
1277 that have been saved after compiling with an external set of tables, because
1278 the external tables might be at a different address when \fBpcre_exec()\fP is
1279 called. See the
1280 .\" HREF
1281 \fBpcreprecompile\fP
1282 .\"
1283 documentation for a discussion of saving compiled patterns for later use.
1284 .
1285 .\" HTML <a name="execoptions"></a>
1286 .SS "Option bits for \fBpcre_exec()\fP"
1287 .rs
1288 .sp
1289 The unused bits of the \fIoptions\fP argument for \fBpcre_exec()\fP must be
1290 zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,
1291 PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1292 PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and
1293 PCRE_PARTIAL_HARD.
1294 .sp
1295 PCRE_ANCHORED
1296 .sp
1297 The PCRE_ANCHORED option limits \fBpcre_exec()\fP to matching at the first
1298 matching position. If a pattern was compiled with PCRE_ANCHORED, or turned out
1299 to be anchored by virtue of its contents, it cannot be made unachored at
1300 matching time.
1301 .sp
1302 PCRE_BSR_ANYCRLF
1303 PCRE_BSR_UNICODE
1304 .sp
1305 These options (which are mutually exclusive) control what the \eR escape
1306 sequence matches. The choice is either to match only CR, LF, or CRLF, or to
1307 match any Unicode newline sequence. These options override the choice that was
1308 made or defaulted when the pattern was compiled.
1309 .sp
1310 PCRE_NEWLINE_CR
1311 PCRE_NEWLINE_LF
1312 PCRE_NEWLINE_CRLF
1313 PCRE_NEWLINE_ANYCRLF
1314 PCRE_NEWLINE_ANY
1315 .sp
1316 These options override the newline definition that was chosen or defaulted when
1317 the pattern was compiled. For details, see the description of
1318 \fBpcre_compile()\fP above. During matching, the newline choice affects the
1319 behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1320 the way the match position is advanced after a match failure for an unanchored
1321 pattern.
1322 .P
1323 When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a
1324 match attempt for an unanchored pattern fails when the current position is at a
1325 CRLF sequence, and the pattern contains no explicit matches for CR or LF
1326 characters, the match position is advanced by two characters instead of one, in
1327 other words, to after the CRLF.
1328 .P
1329 The above rule is a compromise that makes the most common cases work as
1330 expected. For example, if the pattern is .+A (and the PCRE_DOTALL option is not
1331 set), it does not match the string "\er\enA" because, after failing at the
1332 start, it skips both the CR and the LF before retrying. However, the pattern
1333 [\er\en]A does match that string, because it contains an explicit CR or LF
1334 reference, and so advances only by one character after the first failure.
1335 .P
1336 An explicit match for CR of LF is either a literal appearance of one of those
1337 characters, or one of the \er or \en escape sequences. Implicit matches such as
1338 [^X] do not count, nor does \es (which includes CR and LF in the characters
1339 that it matches).
1340 .P
1341 Notwithstanding the above, anomalous effects may still occur when CRLF is a
1342 valid newline sequence and explicit \er or \en escapes appear in the pattern.
1343 .sp
1344 PCRE_NOTBOL
1345 .sp
1346 This option specifies that first character of the subject string is not the
1347 beginning of a line, so the circumflex metacharacter should not match before
1348 it. Setting this without PCRE_MULTILINE (at compile time) causes circumflex
1349 never to match. This option affects only the behaviour of the circumflex
1350 metacharacter. It does not affect \eA.
1351 .sp
1352 PCRE_NOTEOL
1353 .sp
1354 This option specifies that the end of the subject string is not the end of a
1355 line, so the dollar metacharacter should not match it nor (except in multiline
1356 mode) a newline immediately before it. Setting this without PCRE_MULTILINE (at
1357 compile time) causes dollar never to match. This option affects only the
1358 behaviour of the dollar metacharacter. It does not affect \eZ or \ez.
1359 .sp
1360 PCRE_NOTEMPTY
1361 .sp
1362 An empty string is not considered to be a valid match if this option is set. If
1363 there are alternatives in the pattern, they are tried. If all the alternatives
1364 match the empty string, the entire match fails. For example, if the pattern
1365 .sp
1366 a?b?
1367 .sp
1368 is applied to a string not beginning with "a" or "b", it matches an empty
1369 string at the start of the subject. With PCRE_NOTEMPTY set, this match is not
1370 valid, so PCRE searches further into the string for occurrences of "a" or "b".
1371 .sp
1372 PCRE_NOTEMPTY_ATSTART
1373 .sp
1374 This is like PCRE_NOTEMPTY, except that an empty string match that is not at
1375 the start of the subject is permitted. If the pattern is anchored, such a match
1376 can occur only if the pattern contains \eK.
1377 .P
1378 Perl has no direct equivalent of PCRE_NOTEMPTY or PCRE_NOTEMPTY_ATSTART, but it
1379 does make a special case of a pattern match of the empty string within its
1380 \fBsplit()\fP function, and when using the /g modifier. It is possible to
1381 emulate Perl's behaviour after matching a null string by first trying the match
1382 again at the same offset with PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED, and then
1383 if that fails, by advancing the starting offset (see below) and trying an
1384 ordinary match again. There is some code that demonstrates how to do this in
1385 the
1386 .\" HREF
1387 \fBpcredemo\fP
1388 .\"
1389 sample program.
1390 .sp
1391 PCRE_NO_START_OPTIMIZE
1392 .sp
1393 There are a number of optimizations that \fBpcre_exec()\fP uses at the start of
1394 a match, in order to speed up the process. For example, if it is known that a
1395 match must start with a specific character, it searches the subject for that
1396 character, and fails immediately if it cannot find it, without actually running
1397 the main matching function. When callouts are in use, these optimizations can
1398 cause them to be skipped. This option disables the "start-up" optimizations,
1399 causing performance to suffer, but ensuring that the callouts do occur.
1400 .sp
1401 PCRE_NO_UTF8_CHECK
1402 .sp
1403 When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8
1404 string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1405 The value of \fIstartoffset\fP is also checked to ensure that it points to the
1406 start of a UTF-8 character. There is a discussion about the validity of UTF-8
1407 strings in the
1408 .\" HTML <a href="pcre.html#utf8strings">
1409 .\" </a>
1410 section on UTF-8 support
1411 .\"
1412 in the main
1413 .\" HREF
1414 \fBpcre\fP
1415 .\"
1416 page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1417 the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains an invalid value,
1418 PCRE_ERROR_BADUTF8_OFFSET is returned.
1419 .P
1420 If you already know that your subject is valid, and you want to skip these
1421 checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when
1422 calling \fBpcre_exec()\fP. You might want to do this for the second and
1423 subsequent calls to \fBpcre_exec()\fP if you are making repeated calls to find
1424 all the matches in a single subject string. However, you should be sure that
1425 the value of \fIstartoffset\fP points to the start of a UTF-8 character. When
1426 PCRE_NO_UTF8_CHECK is set, the effect of passing an invalid UTF-8 string as a
1427 subject, or a value of \fIstartoffset\fP that does not point to the start of a
1428 UTF-8 character, is undefined. Your program may crash.
1429 .sp
1430 PCRE_PARTIAL_HARD
1431 PCRE_PARTIAL_SOFT
1432 .sp
1433 These options turn on the partial matching feature. For backwards
1434 compatibility, PCRE_PARTIAL is a synonym for PCRE_PARTIAL_SOFT. A partial match
1435 occurs if the end of the subject string is reached successfully, but there are
1436 not enough subject characters to complete the match. If this happens when
1437 PCRE_PARTIAL_HARD is set, \fBpcre_exec()\fP immediately returns
1438 PCRE_ERROR_PARTIAL. Otherwise, if PCRE_PARTIAL_SOFT is set, matching continues
1439 by testing any other alternatives. Only if they all fail is PCRE_ERROR_PARTIAL
1440 returned (instead of PCRE_ERROR_NOMATCH). The portion of the string that
1441 was inspected when the partial match was found is set as the first matching
1442 string. There is a more detailed discussion in the
1443 .\" HREF
1444 \fBpcrepartial\fP
1445 .\"
1446 documentation.
1447 .
1448 .SS "The string to be matched by \fBpcre_exec()\fP"
1449 .rs
1450 .sp
1451 The subject string is passed to \fBpcre_exec()\fP as a pointer in
1452 \fIsubject\fP, a length (in bytes) in \fIlength\fP, and a starting byte offset
1453 in \fIstartoffset\fP. In UTF-8 mode, the byte offset must point to the start of
1454 a UTF-8 character. Unlike the pattern string, the subject may contain binary
1455 zero bytes. When the starting offset is zero, the search for a match starts at
1456 the beginning of the subject, and this is by far the most common case.
1457 .P
1458 A non-zero starting offset is useful when searching for another match in the
1459 same subject by calling \fBpcre_exec()\fP again after a previous success.
1460 Setting \fIstartoffset\fP differs from just passing over a shortened string and
1461 setting PCRE_NOTBOL in the case of a pattern that begins with any kind of
1462 lookbehind. For example, consider the pattern
1463 .sp
1464 \eBiss\eB
1465 .sp
1466 which finds occurrences of "iss" in the middle of words. (\eB matches only if
1467 the current position in the subject is not a word boundary.) When applied to
1468 the string "Mississipi" the first call to \fBpcre_exec()\fP finds the first
1469 occurrence. If \fBpcre_exec()\fP is called again with just the remainder of the
1470 subject, namely "issipi", it does not match, because \eB is always false at the
1471 start of the subject, which is deemed to be a word boundary. However, if
1472 \fBpcre_exec()\fP is passed the entire string again, but with \fIstartoffset\fP
1473 set to 4, it finds the second occurrence of "iss" because it is able to look
1474 behind the starting point to discover that it is preceded by a letter.
1475 .P
1476 If a non-zero starting offset is passed when the pattern is anchored, one
1477 attempt to match at the given offset is made. This can only succeed if the
1478 pattern does not require the match to be at the start of the subject.
1479 .
1480 .SS "How \fBpcre_exec()\fP returns captured substrings"
1481 .rs
1482 .sp
1483 In general, a pattern matches a certain portion of the subject, and in
1484 addition, further substrings from the subject may be picked out by parts of the
1485 pattern. Following the usage in Jeffrey Friedl's book, this is called
1486 "capturing" in what follows, and the phrase "capturing subpattern" is used for
1487 a fragment of a pattern that picks out a substring. PCRE supports several other
1488 kinds of parenthesized subpattern that do not cause substrings to be captured.
1489 .P
1490 Captured substrings are returned to the caller via a vector of integers whose
1491 address is passed in \fIovector\fP. The number of elements in the vector is
1492 passed in \fIovecsize\fP, which must be a non-negative number. \fBNote\fP: this
1493 argument is NOT the size of \fIovector\fP in bytes.
1494 .P
1495 The first two-thirds of the vector is used to pass back captured substrings,
1496 each substring using a pair of integers. The remaining third of the vector is
1497 used as workspace by \fBpcre_exec()\fP while matching capturing subpatterns,
1498 and is not available for passing back information. The number passed in
1499 \fIovecsize\fP should always be a multiple of three. If it is not, it is
1500 rounded down.
1501 .P
1502 When a match is successful, information about captured substrings is returned
1503 in pairs of integers, starting at the beginning of \fIovector\fP, and
1504 continuing up to two-thirds of its length at the most. The first element of
1505 each pair is set to the byte offset of the first character in a substring, and
1506 the second is set to the byte offset of the first character after the end of a
1507 substring. \fBNote\fP: these values are always byte offsets, even in UTF-8
1508 mode. They are not character counts.
1509 .P
1510 The first pair of integers, \fIovector[0]\fP and \fIovector[1]\fP, identify the
1511 portion of the subject string matched by the entire pattern. The next pair is
1512 used for the first capturing subpattern, and so on. The value returned by
1513 \fBpcre_exec()\fP is one more than the highest numbered pair that has been set.
1514 For example, if two substrings have been captured, the returned value is 3. If
1515 there are no capturing subpatterns, the return value from a successful match is
1516 1, indicating that just the first pair of offsets has been set.
1517 .P
1518 If a capturing subpattern is matched repeatedly, it is the last portion of the
1519 string that it matched that is returned.
1520 .P
1521 If the vector is too small to hold all the captured substring offsets, it is
1522 used as far as possible (up to two-thirds of its length), and the function
1523 returns a value of zero. If the substring offsets are not of interest,
1524 \fBpcre_exec()\fP may be called with \fIovector\fP passed as NULL and
1525 \fIovecsize\fP as zero. However, if the pattern contains back references and
1526 the \fIovector\fP is not big enough to remember the related substrings, PCRE
1527 has to get additional memory for use during matching. Thus it is usually
1528 advisable to supply an \fIovector\fP.
1529 .P
1530 The \fBpcre_fullinfo()\fP function can be used to find out how many capturing
1531 subpatterns there are in a compiled pattern. The smallest size for
1532 \fIovector\fP that will allow for \fIn\fP captured substrings, in addition to
1533 the offsets of the substring matched by the whole pattern, is (\fIn\fP+1)*3.
1534 .P
1535 It is possible for capturing subpattern number \fIn+1\fP to match some part of
1536 the subject when subpattern \fIn\fP has not been used at all. For example, if
1537 the string "abc" is matched against the pattern (a|(z))(bc) the return from the
1538 function is 4, and subpatterns 1 and 3 are matched, but 2 is not. When this
1539 happens, both values in the offset pairs corresponding to unused subpatterns
1540 are set to -1.
1541 .P
1542 Offset values that correspond to unused subpatterns at the end of the
1543 expression are also set to -1. For example, if the string "abc" is matched
1544 against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not matched. The
1545 return from the function is 2, because the highest used capturing subpattern
1546 number is 1. However, you can refer to the offsets for the second and third
1547 capturing subpatterns if you wish (assuming the vector is large enough, of
1548 course).
1549 .P
1550 Some convenience functions are provided for extracting the captured substrings
1551 as separate strings. These are described below.
1552 .
1553 .\" HTML <a name="errorlist"></a>
1554 .SS "Error return values from \fBpcre_exec()\fP"
1555 .rs
1556 .sp
1557 If \fBpcre_exec()\fP fails, it returns a negative number. The following are
1558 defined in the header file:
1559 .sp
1560 PCRE_ERROR_NOMATCH (-1)
1561 .sp
1562 The subject string did not match the pattern.
1563 .sp
1564 PCRE_ERROR_NULL (-2)
1565 .sp
1566 Either \fIcode\fP or \fIsubject\fP was passed as NULL, or \fIovector\fP was
1567 NULL and \fIovecsize\fP was not zero.
1568 .sp
1569 PCRE_ERROR_BADOPTION (-3)
1570 .sp
1571 An unrecognized bit was set in the \fIoptions\fP argument.
1572 .sp
1573 PCRE_ERROR_BADMAGIC (-4)
1574 .sp
1575 PCRE stores a 4-byte "magic number" at the start of the compiled code, to catch
1576 the case when it is passed a junk pointer and to detect when a pattern that was
1577 compiled in an environment of one endianness is run in an environment with the
1578 other endianness. This is the error that PCRE gives when the magic number is
1579 not present.
1580 .sp
1581 PCRE_ERROR_UNKNOWN_OPCODE (-5)
1582 .sp
1583 While running the pattern match, an unknown item was encountered in the
1584 compiled pattern. This error could be caused by a bug in PCRE or by overwriting
1585 of the compiled pattern.
1586 .sp
1587 PCRE_ERROR_NOMEMORY (-6)
1588 .sp
1589 If a pattern contains back references, but the \fIovector\fP that is passed to
1590 \fBpcre_exec()\fP is not big enough to remember the referenced substrings, PCRE
1591 gets a block of memory at the start of matching to use for this purpose. If the
1592 call via \fBpcre_malloc()\fP fails, this error is given. The memory is
1593 automatically freed at the end of matching.
1594 .sp
1595 PCRE_ERROR_NOSUBSTRING (-7)
1596 .sp
1597 This error is used by the \fBpcre_copy_substring()\fP,
1598 \fBpcre_get_substring()\fP, and \fBpcre_get_substring_list()\fP functions (see
1599 below). It is never returned by \fBpcre_exec()\fP.
1600 .sp
1601 PCRE_ERROR_MATCHLIMIT (-8)
1602 .sp
1603 The backtracking limit, as specified by the \fImatch_limit\fP field in a
1604 \fBpcre_extra\fP structure (or defaulted) was reached. See the description
1605 above.
1606 .sp
1607 PCRE_ERROR_CALLOUT (-9)
1608 .sp
1609 This error is never generated by \fBpcre_exec()\fP itself. It is provided for
1610 use by callout functions that want to yield a distinctive error code. See the
1611 .\" HREF
1612 \fBpcrecallout\fP
1613 .\"
1614 documentation for details.
1615 .sp
1616 PCRE_ERROR_BADUTF8 (-10)
1617 .sp
1618 A string that contains an invalid UTF-8 byte sequence was passed as a subject.
1619 .sp
1620 PCRE_ERROR_BADUTF8_OFFSET (-11)
1621 .sp
1622 The UTF-8 byte sequence that was passed as a subject was valid, but the value
1623 of \fIstartoffset\fP did not point to the beginning of a UTF-8 character.
1624 .sp
1625 PCRE_ERROR_PARTIAL (-12)
1626 .sp
1627 The subject string did not match, but it did match partially. See the
1628 .\" HREF
1629 \fBpcrepartial\fP
1630 .\"
1631 documentation for details of partial matching.
1632 .sp
1633 PCRE_ERROR_BADPARTIAL (-13)
1634 .sp
1635 This code is no longer in use. It was formerly returned when the PCRE_PARTIAL
1636 option was used with a compiled pattern containing items that were not
1637 supported for partial matching. From release 8.00 onwards, there are no
1638 restrictions on partial matching.
1639 .sp
1640 PCRE_ERROR_INTERNAL (-14)
1641 .sp
1642 An unexpected internal error has occurred. This error could be caused by a bug
1643 in PCRE or by overwriting of the compiled pattern.
1644 .sp
1645 PCRE_ERROR_BADCOUNT (-15)
1646 .sp
1647 This error is given if the value of the \fIovecsize\fP argument is negative.
1648 .sp
1649 PCRE_ERROR_RECURSIONLIMIT (-21)
1650 .sp
1651 The internal recursion limit, as specified by the \fImatch_limit_recursion\fP
1652 field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the
1653 description above.
1654 .sp
1655 PCRE_ERROR_BADNEWLINE (-23)
1656 .sp
1657 An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
1658 .P
1659 Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
1660 .
1661 .
1662 .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
1663 .rs
1664 .sp
1665 .B int pcre_copy_substring(const char *\fIsubject\fP, int *\fIovector\fP,
1666 .ti +5n
1667 .B int \fIstringcount\fP, int \fIstringnumber\fP, char *\fIbuffer\fP,
1668 .ti +5n
1669 .B int \fIbuffersize\fP);
1670 .PP
1671 .B int pcre_get_substring(const char *\fIsubject\fP, int *\fIovector\fP,
1672 .ti +5n
1673 .B int \fIstringcount\fP, int \fIstringnumber\fP,
1674 .ti +5n
1675 .B const char **\fIstringptr\fP);
1676 .PP
1677 .B int pcre_get_substring_list(const char *\fIsubject\fP,
1678 .ti +5n
1679 .B int *\fIovector\fP, int \fIstringcount\fP, "const char ***\fIlistptr\fP);"
1680 .PP
1681 Captured substrings can be accessed directly by using the offsets returned by
1682 \fBpcre_exec()\fP in \fIovector\fP. For convenience, the functions
1683 \fBpcre_copy_substring()\fP, \fBpcre_get_substring()\fP, and
1684 \fBpcre_get_substring_list()\fP are provided for extracting captured substrings
1685 as new, separate, zero-terminated strings. These functions identify substrings
1686 by number. The next section describes functions for extracting named
1687 substrings.
1688 .P
1689 A substring that contains a binary zero is correctly extracted and has a
1690 further zero added on the end, but the result is not, of course, a C string.
1691 However, you can process such a string by referring to the length that is
1692 returned by \fBpcre_copy_substring()\fP and \fBpcre_get_substring()\fP.
1693 Unfortunately, the interface to \fBpcre_get_substring_list()\fP is not adequate
1694 for handling strings containing binary zeros, because the end of the final
1695 string is not independently indicated.
1696 .P
1697 The first three arguments are the same for all three of these functions:
1698 \fIsubject\fP is the subject string that has just been successfully matched,
1699 \fIovector\fP is a pointer to the vector of integer offsets that was passed to
1700 \fBpcre_exec()\fP, and \fIstringcount\fP is the number of substrings that were
1701 captured by the match, including the substring that matched the entire regular
1702 expression. This is the value returned by \fBpcre_exec()\fP if it is greater
1703 than zero. If \fBpcre_exec()\fP returned zero, indicating that it ran out of
1704 space in \fIovector\fP, the value passed as \fIstringcount\fP should be the
1705 number of elements in the vector divided by three.
1706 .P
1707 The functions \fBpcre_copy_substring()\fP and \fBpcre_get_substring()\fP
1708 extract a single substring, whose number is given as \fIstringnumber\fP. A
1709 value of zero extracts the substring that matched the entire pattern, whereas
1710 higher values extract the captured substrings. For \fBpcre_copy_substring()\fP,
1711 the string is placed in \fIbuffer\fP, whose length is given by
1712 \fIbuffersize\fP, while for \fBpcre_get_substring()\fP a new block of memory is
1713 obtained via \fBpcre_malloc\fP, and its address is returned via
1714 \fIstringptr\fP. The yield of the function is the length of the string, not
1715 including the terminating zero, or one of these error codes:
1716 .sp
1717 PCRE_ERROR_NOMEMORY (-6)
1718 .sp
1719 The buffer was too small for \fBpcre_copy_substring()\fP, or the attempt to get
1720 memory failed for \fBpcre_get_substring()\fP.
1721 .sp
1722 PCRE_ERROR_NOSUBSTRING (-7)
1723 .sp
1724 There is no substring whose number is \fIstringnumber\fP.
1725 .P
1726 The \fBpcre_get_substring_list()\fP function extracts all available substrings
1727 and builds a list of pointers to them. All this is done in a single block of
1728 memory that is obtained via \fBpcre_malloc\fP. The address of the memory block
1729 is returned via \fIlistptr\fP, which is also the start of the list of string
1730 pointers. The end of the list is marked by a NULL pointer. The yield of the
1731 function is zero if all went well, or the error code
1732 .sp
1733 PCRE_ERROR_NOMEMORY (-6)
1734 .sp
1735 if the attempt to get the memory block failed.
1736 .P
1737 When any of these functions encounter a substring that is unset, which can
1738 happen when capturing subpattern number \fIn+1\fP matches some part of the
1739 subject, but subpattern \fIn\fP has not been used at all, they return an empty
1740 string. This can be distinguished from a genuine zero-length substring by
1741 inspecting the appropriate offset in \fIovector\fP, which is negative for unset
1742 substrings.
1743 .P
1744 The two convenience functions \fBpcre_free_substring()\fP and
1745 \fBpcre_free_substring_list()\fP can be used to free the memory returned by
1746 a previous call of \fBpcre_get_substring()\fP or
1747 \fBpcre_get_substring_list()\fP, respectively. They do nothing more than call
1748 the function pointed to by \fBpcre_free\fP, which of course could be called
1749 directly from a C program. However, PCRE is used in some situations where it is
1750 linked via a special interface to another programming language that cannot use
1751 \fBpcre_free\fP directly; it is for these cases that the functions are
1752 provided.
1753 .
1754 .
1755 .SH "EXTRACTING CAPTURED SUBSTRINGS BY NAME"
1756 .rs
1757 .sp
1758 .B int pcre_get_stringnumber(const pcre *\fIcode\fP,
1759 .ti +5n
1760 .B const char *\fIname\fP);
1761 .PP
1762 .B int pcre_copy_named_substring(const pcre *\fIcode\fP,
1763 .ti +5n
1764 .B const char *\fIsubject\fP, int *\fIovector\fP,
1765 .ti +5n
1766 .B int \fIstringcount\fP, const char *\fIstringname\fP,
1767 .ti +5n
1768 .B char *\fIbuffer\fP, int \fIbuffersize\fP);
1769 .PP
1770 .B int pcre_get_named_substring(const pcre *\fIcode\fP,
1771 .ti +5n
1772 .B const char *\fIsubject\fP, int *\fIovector\fP,
1773 .ti +5n
1774 .B int \fIstringcount\fP, const char *\fIstringname\fP,
1775 .ti +5n
1776 .B const char **\fIstringptr\fP);
1777 .PP
1778 To extract a substring by name, you first have to find associated number.
1779 For example, for this pattern
1780 .sp
1781 (a+)b(?<xxx>\ed+)...
1782 .sp
1783 the number of the subpattern called "xxx" is 2. If the name is known to be
1784 unique (PCRE_DUPNAMES was not set), you can find the number from the name by
1785 calling \fBpcre_get_stringnumber()\fP. The first argument is the compiled
1786 pattern, and the second is the name. The yield of the function is the
1787 subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no subpattern of
1788 that name.
1789 .P
1790 Given the number, you can extract the substring directly, or use one of the
1791 functions described in the previous section. For convenience, there are also
1792 two functions that do the whole job.
1793 .P
1794 Most of the arguments of \fBpcre_copy_named_substring()\fP and
1795 \fBpcre_get_named_substring()\fP are the same as those for the similarly named
1796 functions that extract by number. As these are described in the previous
1797 section, they are not re-described here. There are just two differences:
1798 .P
1799 First, instead of a substring number, a substring name is given. Second, there
1800 is an extra argument, given at the start, which is a pointer to the compiled
1801 pattern. This is needed in order to gain access to the name-to-number
1802 translation table.
1803 .P
1804 These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they
1805 then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1806 appropriate. \fBNOTE:\fP If PCRE_DUPNAMES is set and there are duplicate names,
1807 the behaviour may not be what you want (see the next section).
1808 .P
1809 \fBWarning:\fP If the pattern uses the (?| feature to set up multiple
1810 subpatterns with the same number, as described in the
1811 .\" HTML <a href="pcrepattern.html#dupsubpatternnumber">
1812 .\" </a>
1813 section on duplicate subpattern numbers
1814 .\"
1815 in the
1816 .\" HREF
1817 \fBpcrepattern\fP
1818 .\"
1819 page, you cannot use names to distinguish the different subpatterns, because
1820 names are not included in the compiled code. The matching process uses only
1821 numbers. For this reason, the use of different names for subpatterns of the
1822 same number causes an error at compile time.
1823 .
1824 .SH "DUPLICATE SUBPATTERN NAMES"
1825 .rs
1826 .sp
1827 .B int pcre_get_stringtable_entries(const pcre *\fIcode\fP,
1828 .ti +5n
1829 .B const char *\fIname\fP, char **\fIfirst\fP, char **\fIlast\fP);
1830 .PP
1831 When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns
1832 are not required to be unique. (Duplicate names are always allowed for
1833 subpatterns with the same number, created by using the (?| feature. Indeed, if
1834 such subpatterns are named, they are required to use the same names.)
1835 .P
1836 Normally, patterns with duplicate names are such that in any one match, only
1837 one of the named subpatterns participates. An example is shown in the
1838 .\" HREF
1839 \fBpcrepattern\fP
1840 .\"
1841 documentation.
1842 .P
1843 When duplicates are present, \fBpcre_copy_named_substring()\fP and
1844 \fBpcre_get_named_substring()\fP return the first substring corresponding to
1845 the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is
1846 returned; no data is returned. The \fBpcre_get_stringnumber()\fP function
1847 returns one of the numbers that are associated with the name, but it is not
1848 defined which it is.
1849 .P
1850 If you want to get full details of all captured substrings for a given name,
1851 you must use the \fBpcre_get_stringtable_entries()\fP function. The first
1852 argument is the compiled pattern, and the second is the name. The third and
1853 fourth are pointers to variables which are updated by the function. After it
1854 has run, they point to the first and last entries in the name-to-number table
1855 for the given name. The function itself returns the length of each entry, or
1856 PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is
1857 described above in the section entitled \fIInformation about a pattern\fP.
1858 Given all the relevant entries for the name, you can extract each of their
1859 numbers, and hence the captured data, if any.
1860 .
1861 .
1862 .SH "FINDING ALL POSSIBLE MATCHES"
1863 .rs
1864 .sp
1865 The traditional matching function uses a similar algorithm to Perl, which stops
1866 when it finds the first match, starting at a given point in the subject. If you
1867 want to find all possible matches, or the longest possible match, consider
1868 using the alternative matching function (see below) instead. If you cannot use
1869 the alternative function, but still need to find all possible matches, you
1870 can kludge it up by making use of the callout facility, which is described in
1871 the
1872 .\" HREF
1873 \fBpcrecallout\fP
1874 .\"
1875 documentation.
1876 .P
1877 What you have to do is to insert a callout right at the end of the pattern.
1878 When your callout function is called, extract and save the current matched
1879 substring. Then return 1, which forces \fBpcre_exec()\fP to backtrack and try
1880 other alternatives. Ultimately, when it runs out of matches, \fBpcre_exec()\fP
1881 will yield PCRE_ERROR_NOMATCH.
1882 .
1883 .
1884 .\" HTML <a name="dfamatch"></a>
1885 .SH "MATCHING A PATTERN: THE ALTERNATIVE FUNCTION"
1886 .rs
1887 .sp
1888 .B int pcre_dfa_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
1889 .ti +5n
1890 .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
1891 .ti +5n
1892 .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP,
1893 .ti +5n
1894 .B int *\fIworkspace\fP, int \fIwscount\fP);
1895 .P
1896 The function \fBpcre_dfa_exec()\fP is called to match a subject string against
1897 a compiled pattern, using a matching algorithm that scans the subject string
1898 just once, and does not backtrack. This has different characteristics to the
1899 normal algorithm, and is not compatible with Perl. Some of the features of PCRE
1900 patterns are not supported. Nevertheless, there are times when this kind of
1901 matching can be useful. For a discussion of the two matching algorithms, and a
1902 list of features that \fBpcre_dfa_exec()\fP does not support, see the
1903 .\" HREF
1904 \fBpcrematching\fP
1905 .\"
1906 documentation.
1907 .P
1908 The arguments for the \fBpcre_dfa_exec()\fP function are the same as for
1909 \fBpcre_exec()\fP, plus two extras. The \fIovector\fP argument is used in a
1910 different way, and this is described below. The other common arguments are used
1911 in the same way as for \fBpcre_exec()\fP, so their description is not repeated
1912 here.
1913 .P
1914 The two additional arguments provide workspace for the function. The workspace
1915 vector should contain at least 20 elements. It is used for keeping track of
1916 multiple paths through the pattern tree. More workspace will be needed for
1917 patterns and subjects where there are a lot of potential matches.
1918 .P
1919 Here is an example of a simple call to \fBpcre_dfa_exec()\fP:
1920 .sp
1921 int rc;
1922 int ovector[10];
1923 int wspace[20];
1924 rc = pcre_dfa_exec(
1925 re, /* result of pcre_compile() */
1926 NULL, /* we didn't study the pattern */
1927 "some string", /* the subject string */
1928 11, /* the length of the subject string */
1929 0, /* start at offset 0 in the subject */
1930 0, /* default options */
1931 ovector, /* vector of integers for substring information */
1932 10, /* number of elements (NOT size in bytes) */
1933 wspace, /* working space vector */
1934 20); /* number of elements (NOT size in bytes) */
1935 .
1936 .SS "Option bits for \fBpcre_dfa_exec()\fP"
1937 .rs
1938 .sp
1939 The unused bits of the \fIoptions\fP argument for \fBpcre_dfa_exec()\fP must be
1940 zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,
1941 PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1942 PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, PCRE_PARTIAL_SOFT, PCRE_DFA_SHORTEST,
1943 and PCRE_DFA_RESTART. All but the last four of these are exactly the same as
1944 for \fBpcre_exec()\fP, so their description is not repeated here.
1945 .sp
1946 PCRE_PARTIAL_HARD
1947 PCRE_PARTIAL_SOFT
1948 .sp
1949 These have the same general effect as they do for \fBpcre_exec()\fP, but the
1950 details are slightly different. When PCRE_PARTIAL_HARD is set for
1951 \fBpcre_dfa_exec()\fP, it returns PCRE_ERROR_PARTIAL if the end of the subject
1952 is reached and there is still at least one matching possibility that requires
1953 additional characters. This happens even if some complete matches have also
1954 been found. When PCRE_PARTIAL_SOFT is set, the return code PCRE_ERROR_NOMATCH
1955 is converted into PCRE_ERROR_PARTIAL if the end of the subject is reached,
1956 there have been no complete matches, but there is still at least one matching
1957 possibility. The portion of the string that was inspected when the longest
1958 partial match was found is set as the first matching string in both cases.
1959 .sp
1960 PCRE_DFA_SHORTEST
1961 .sp
1962 Setting the PCRE_DFA_SHORTEST option causes the matching algorithm to stop as
1963 soon as it has found one match. Because of the way the alternative algorithm
1964 works, this is necessarily the shortest possible match at the first possible
1965 matching point in the subject string.
1966 .sp
1967 PCRE_DFA_RESTART
1968 .sp
1969 When \fBpcre_dfa_exec()\fP returns a partial match, it is possible to call it
1970 again, with additional subject characters, and have it continue with the same
1971 match. The PCRE_DFA_RESTART option requests this action; when it is set, the
1972 \fIworkspace\fP and \fIwscount\fP options must reference the same vector as
1973 before because data about the match so far is left in them after a partial
1974 match. There is more discussion of this facility in the
1975 .\" HREF
1976 \fBpcrepartial\fP
1977 .\"
1978 documentation.
1979 .
1980 .SS "Successful returns from \fBpcre_dfa_exec()\fP"
1981 .rs
1982 .sp
1983 When \fBpcre_dfa_exec()\fP succeeds, it may have matched more than one
1984 substring in the subject. Note, however, that all the matches from one run of
1985 the function start at the same point in the subject. The shorter matches are
1986 all initial substrings of the longer matches. For example, if the pattern
1987 .sp
1988 <.*>
1989 .sp
1990 is matched against the string
1991 .sp
1992 This is <something> <something else> <something further> no more
1993 .sp
1994 the three matched strings are
1995 .sp
1996 <something>
1997 <something> <something else>
1998 <something> <something else> <something further>
1999 .sp
2000 On success, the yield of the function is a number greater than zero, which is
2001 the number of matched substrings. The substrings themselves are returned in
2002 \fIovector\fP. Each string uses two elements; the first is the offset to the
2003 start, and the second is the offset to the end. In fact, all the strings have
2004 the same start offset. (Space could have been saved by giving this only once,
2005 but it was decided to retain some compatibility with the way \fBpcre_exec()\fP
2006 returns data, even though the meaning of the strings is different.)
2007 .P
2008 The strings are returned in reverse order of length; that is, the longest
2009 matching string is given first. If there were too many matches to fit into
2010 \fIovector\fP, the yield of the function is zero, and the vector is filled with
2011 the longest matches.
2012 .
2013 .SS "Error returns from \fBpcre_dfa_exec()\fP"
2014 .rs
2015 .sp
2016 The \fBpcre_dfa_exec()\fP function returns a negative number when it fails.
2017 Many of the errors are the same as for \fBpcre_exec()\fP, and these are
2018 described
2019 .\" HTML <a href="#errorlist">
2020 .\" </a>
2021 above.
2022 .\"
2023 There are in addition the following errors that are specific to
2024 \fBpcre_dfa_exec()\fP:
2025 .sp
2026 PCRE_ERROR_DFA_UITEM (-16)
2027 .sp
2028 This return is given if \fBpcre_dfa_exec()\fP encounters an item in the pattern
2029 that it does not support, for instance, the use of \eC or a back reference.
2030 .sp
2031 PCRE_ERROR_DFA_UCOND (-17)
2032 .sp
2033 This return is given if \fBpcre_dfa_exec()\fP encounters a condition item that
2034 uses a back reference for the condition, or a test for recursion in a specific
2035 group. These are not supported.
2036 .sp
2037 PCRE_ERROR_DFA_UMLIMIT (-18)
2038 .sp
2039 This return is given if \fBpcre_dfa_exec()\fP is called with an \fIextra\fP
2040 block that contains a setting of the \fImatch_limit\fP field. This is not
2041 supported (it is meaningless).
2042 .sp
2043 PCRE_ERROR_DFA_WSSIZE (-19)
2044 .sp
2045 This return is given if \fBpcre_dfa_exec()\fP runs out of space in the
2046 \fIworkspace\fP vector.
2047 .sp
2048 PCRE_ERROR_DFA_RECURSE (-20)
2049 .sp
2050 When a recursive subpattern is processed, the matching function calls itself
2051 recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This
2052 error is given if the output vector is not large enough. This should be
2053 extremely rare, as a vector of size 1000 is used.
2054 .
2055 .
2056 .SH "SEE ALSO"
2057 .rs
2058 .sp
2059 \fBpcrebuild\fP(3), \fBpcrecallout\fP(3), \fBpcrecpp(3)\fP(3),
2060 \fBpcrematching\fP(3), \fBpcrepartial\fP(3), \fBpcreposix\fP(3),
2061 \fBpcreprecompile\fP(3), \fBpcresample\fP(3), \fBpcrestack\fP(3).
2062 .
2063 .
2064 .SH AUTHOR
2065 .rs
2066 .sp
2067 .nf
2068 Philip Hazel
2069 University Computing Service
2070 Cambridge CB2 3QH, England.
2071 .fi
2072 .
2073 .
2074 .SH REVISION
2075 .rs
2076 .sp
2077 .nf
2078 Last updated: 03 October 2009
2079 Copyright (c) 1997-2009 University of Cambridge.
2080 .fi

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