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1 <html>
2 <head>
3 <title>pcretest specification</title>
4 </head>
5 <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6 <h1>pcretest man page</h1>
7 <p>
8 Return to the <a href="index.html">PCRE index page</a>.
9 </p>
10 <p>
11 This page is part of the PCRE HTML documentation. It was generated automatically
12 from the original man page. If there is any nonsense in it, please consult the
13 man page, in case the conversion went wrong.
14 <br>
15 <ul>
16 <li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
17 <li><a name="TOC2" href="#SEC2">OPTIONS</a>
18 <li><a name="TOC3" href="#SEC3">DESCRIPTION</a>
19 <li><a name="TOC4" href="#SEC4">PATTERN MODIFIERS</a>
20 <li><a name="TOC5" href="#SEC5">DATA LINES</a>
21 <li><a name="TOC6" href="#SEC6">THE ALTERNATIVE MATCHING FUNCTION</a>
22 <li><a name="TOC7" href="#SEC7">DEFAULT OUTPUT FROM PCRETEST</a>
24 <li><a name="TOC9" href="#SEC9">RESTARTING AFTER A PARTIAL MATCH</a>
25 <li><a name="TOC10" href="#SEC10">CALLOUTS</a>
26 <li><a name="TOC11" href="#SEC11">NON-PRINTING CHARACTERS</a>
28 <li><a name="TOC13" href="#SEC13">SEE ALSO</a>
29 <li><a name="TOC14" href="#SEC14">AUTHOR</a>
30 <li><a name="TOC15" href="#SEC15">REVISION</a>
31 </ul>
32 <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
33 <P>
34 <b>pcretest [options] [source] [destination]</b>
35 <br>
36 <br>
37 <b>pcretest</b> was written as a test program for the PCRE regular expression
38 library itself, but it can also be used for experimenting with regular
39 expressions. This document describes the features of the test program; for
40 details of the regular expressions themselves, see the
41 <a href="pcrepattern.html"><b>pcrepattern</b></a>
42 documentation. For details of the PCRE library function calls and their
43 options, see the
44 <a href="pcreapi.html"><b>pcreapi</b></a>
45 documentation.
46 </P>
47 <br><a name="SEC2" href="#TOC1">OPTIONS</a><br>
48 <P>
49 <b>-b</b>
50 Behave as if each regex has the <b>/B</b> (show bytecode) modifier; the internal
51 form is output after compilation.
52 </P>
53 <P>
54 <b>-C</b>
55 Output the version number of the PCRE library, and all available information
56 about the optional features that are included, and then exit.
57 </P>
58 <P>
59 <b>-d</b>
60 Behave as if each regex has the <b>/D</b> (debug) modifier; the internal
61 form and information about the compiled pattern is output after compilation;
62 <b>-d</b> is equivalent to <b>-b -i</b>.
63 </P>
64 <P>
65 <b>-dfa</b>
66 Behave as if each data line contains the \D escape sequence; this causes the
67 alternative matching function, <b>pcre_dfa_exec()</b>, to be used instead of the
68 standard <b>pcre_exec()</b> function (more detail is given below).
69 </P>
70 <P>
71 <b>-help</b>
72 Output a brief summary these options and then exit.
73 </P>
74 <P>
75 <b>-i</b>
76 Behave as if each regex has the <b>/I</b> modifier; information about the
77 compiled pattern is given after compilation.
78 </P>
79 <P>
80 <b>-m</b>
81 Output the size of each compiled pattern after it has been compiled. This is
82 equivalent to adding <b>/M</b> to each regular expression. For compatibility
83 with earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>.
84 </P>
85 <P>
86 <b>-o</b> <i>osize</i>
87 Set the number of elements in the output vector that is used when calling
88 <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> to be <i>osize</i>. The default value
89 is 45, which is enough for 14 capturing subexpressions for <b>pcre_exec()</b> or
90 22 different matches for <b>pcre_dfa_exec()</b>. The vector size can be
91 changed for individual matching calls by including \O in the data line (see
92 below).
93 </P>
94 <P>
95 <b>-p</b>
96 Behave as if each regex has the <b>/P</b> modifier; the POSIX wrapper API is
97 used to call PCRE. None of the other options has any effect when <b>-p</b> is
98 set.
99 </P>
100 <P>
101 <b>-q</b>
102 Do not output the version number of <b>pcretest</b> at the start of execution.
103 </P>
104 <P>
105 <b>-S</b> <i>size</i>
106 On Unix-like systems, set the size of the runtime stack to <i>size</i>
107 megabytes.
108 </P>
109 <P>
110 <b>-t</b>
111 Run each compile, study, and match many times with a timer, and output
112 resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with
113 <b>-t</b>, because you will then get the size output a zillion times, and the
114 timing will be distorted. You can control the number of iterations that are
115 used for timing by following <b>-t</b> with a number (as a separate item on the
116 command line). For example, "-t 1000" would iterate 1000 times. The default is
117 to iterate 500000 times.
118 </P>
119 <P>
120 <b>-tm</b>
121 This is like <b>-t</b> except that it times only the matching phase, not the
122 compile or study phases.
123 </P>
124 <br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br>
125 <P>
126 If <b>pcretest</b> is given two filename arguments, it reads from the first and
127 writes to the second. If it is given only one filename argument, it reads from
128 that file and writes to stdout. Otherwise, it reads from stdin and writes to
129 stdout, and prompts for each line of input, using "re&#62;" to prompt for regular
130 expressions, and "data&#62;" to prompt for data lines.
131 </P>
132 <P>
133 The program handles any number of sets of input on a single input file. Each
134 set starts with a regular expression, and continues with any number of data
135 lines to be matched against the pattern.
136 </P>
137 <P>
138 Each data line is matched separately and independently. If you want to do
139 multi-line matches, you have to use the \n escape sequence (or \r or \r\n,
140 etc., depending on the newline setting) in a single line of input to encode the
141 newline sequences. There is no limit on the length of data lines; the input
142 buffer is automatically extended if it is too small.
143 </P>
144 <P>
145 An empty line signals the end of the data lines, at which point a new regular
146 expression is read. The regular expressions are given enclosed in any
147 non-alphanumeric delimiters other than backslash, for example:
148 <pre>
149 /(a|bc)x+yz/
150 </pre>
151 White space before the initial delimiter is ignored. A regular expression may
152 be continued over several input lines, in which case the newline characters are
153 included within it. It is possible to include the delimiter within the pattern
154 by escaping it, for example
155 <pre>
156 /abc\/def/
157 </pre>
158 If you do so, the escape and the delimiter form part of the pattern, but since
159 delimiters are always non-alphanumeric, this does not affect its interpretation.
160 If the terminating delimiter is immediately followed by a backslash, for
161 example,
162 <pre>
163 /abc/\
164 </pre>
165 then a backslash is added to the end of the pattern. This is done to provide a
166 way of testing the error condition that arises if a pattern finishes with a
167 backslash, because
168 <pre>
169 /abc\/
170 </pre>
171 is interpreted as the first line of a pattern that starts with "abc/", causing
172 pcretest to read the next line as a continuation of the regular expression.
173 </P>
174 <br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br>
175 <P>
176 A pattern may be followed by any number of modifiers, which are mostly single
177 characters. Following Perl usage, these are referred to below as, for example,
178 "the <b>/i</b> modifier", even though the delimiter of the pattern need not
179 always be a slash, and no slash is used when writing modifiers. Whitespace may
180 appear between the final pattern delimiter and the first modifier, and between
181 the modifiers themselves.
182 </P>
183 <P>
184 The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
185 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
186 <b>pcre_compile()</b> is called. These four modifier letters have the same
187 effect as they do in Perl. For example:
188 <pre>
189 /caseless/i
190 </pre>
191 The following table shows additional modifiers for setting PCRE options that do
192 not correspond to anything in Perl:
193 <pre>
194 <b>/A</b> PCRE_ANCHORED
197 <b>/f</b> PCRE_FIRSTLINE
198 <b>/J</b> PCRE_DUPNAMES
200 <b>/U</b> PCRE_UNGREEDY
201 <b>/X</b> PCRE_EXTRA
202 <b>/&#60;cr&#62;</b> PCRE_NEWLINE_CR
203 <b>/&#60;lf&#62;</b> PCRE_NEWLINE_LF
204 <b>/&#60;crlf&#62;</b> PCRE_NEWLINE_CRLF
205 <b>/&#60;any&#62;</b> PCRE_NEWLINE_ANY
206 </pre>
207 Those specifying line ending sequencess are literal strings as shown. This
208 example sets multiline matching with CRLF as the line ending sequence:
209 <pre>
210 /^abc/m&#60;crlf&#62;
211 </pre>
212 Details of the meanings of these PCRE options are given in the
213 <a href="pcreapi.html"><b>pcreapi</b></a>
214 documentation.
215 </P>
216 <br><b>
217 Finding all matches in a string
218 </b><br>
219 <P>
220 Searching for all possible matches within each subject string can be requested
221 by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
222 again to search the remainder of the subject string. The difference between
223 <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
224 <b>pcre_exec()</b> to start searching at a new point within the entire string
225 (which is in effect what Perl does), whereas the latter passes over a shortened
226 substring. This makes a difference to the matching process if the pattern
227 begins with a lookbehind assertion (including \b or \B).
228 </P>
229 <P>
230 If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an
231 empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
232 flags set in order to search for another, non-empty, match at the same point.
233 If this second match fails, the start offset is advanced by one, and the normal
234 match is retried. This imitates the way Perl handles such cases when using the
235 <b>/g</b> modifier or the <b>split()</b> function.
236 </P>
237 <br><b>
238 Other modifiers
239 </b><br>
240 <P>
241 There are yet more modifiers for controlling the way <b>pcretest</b>
242 operates.
243 </P>
244 <P>
245 The <b>/+</b> modifier requests that as well as outputting the substring that
246 matched the entire pattern, pcretest should in addition output the remainder of
247 the subject string. This is useful for tests where the subject contains
248 multiple copies of the same substring.
249 </P>
250 <P>
251 The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
252 output a representation of the compiled byte code after compilation. Normally
253 this information contains length and offset values; however, if <b>/Z</b> is
254 also present, this data is replaced by spaces. This is a special feature for
255 use in the automatic test scripts; it ensures that the same output is generated
256 for different internal link sizes.
257 </P>
258 <P>
259 The <b>/L</b> modifier must be followed directly by the name of a locale, for
260 example,
261 <pre>
262 /pattern/Lfr_FR
263 </pre>
264 For this reason, it must be the last modifier. The given locale is set,
265 <b>pcre_maketables()</b> is called to build a set of character tables for the
266 locale, and this is then passed to <b>pcre_compile()</b> when compiling the
267 regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables
268 pointer; that is, <b>/L</b> applies only to the expression on which it appears.
269 </P>
270 <P>
271 The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
272 compiled pattern (whether it is anchored, has a fixed first character, and
273 so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
274 pattern. If the pattern is studied, the results of that are also output.
275 </P>
276 <P>
277 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
278 <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
279 </P>
280 <P>
281 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
282 fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
283 facility is for testing the feature in PCRE that allows it to execute patterns
284 that were compiled on a host with a different endianness. This feature is not
285 available when the POSIX interface to PCRE is being used, that is, when the
286 <b>/P</b> pattern modifier is specified. See also the section about saving and
287 reloading compiled patterns below.
288 </P>
289 <P>
290 The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the
291 expression has been compiled, and the results used when the expression is
292 matched.
293 </P>
294 <P>
295 The <b>/M</b> modifier causes the size of memory block used to hold the compiled
296 pattern to be output.
297 </P>
298 <P>
299 The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
300 API rather than its native API. When this is done, all other modifiers except
301 <b>/i</b>, <b>/m</b>, and <b>/+</b> are ignored. REG_ICASE is set if <b>/i</b> is
302 present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions
303 force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
304 </P>
305 <P>
306 The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8
307 option set. This turns on support for UTF-8 character handling in PCRE,
308 provided that it was compiled with this support enabled. This modifier also
309 causes any non-printing characters in output strings to be printed using the
310 \x{hh...} notation if they are valid UTF-8 sequences.
311 </P>
312 <P>
313 If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to
314 call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the
315 checking of the string for UTF-8 validity.
316 </P>
317 <br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
318 <P>
319 Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
320 whitespace is removed, and it is then scanned for \ escapes. Some of these are
321 pretty esoteric features, intended for checking out some of the more
322 complicated features of PCRE. If you are just testing "ordinary" regular
323 expressions, you probably don't need any of these. The following escapes are
324 recognized:
325 <pre>
326 \a alarm (BEL, \x07)
327 \b backspace (\x08)
328 \e escape (\x27)
329 \f formfeed (\x0c)
330 \n newline (\x0a)
331 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
332 \r carriage return (\x0d)
333 \t tab (\x09)
334 \v vertical tab (\x0b)
335 \nnn octal character (up to 3 octal digits)
336 \xhh hexadecimal character (up to 2 hex digits)
337 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode
338 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
339 \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
340 \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32)
341 \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
342 ated by next non alphanumeric character)
343 \C+ show the current captured substrings at callout time
344 \C- do not supply a callout function
345 \C!n return 1 instead of 0 when callout number n is reached
346 \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
347 \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
348 \D use the <b>pcre_dfa_exec()</b> match function
349 \F only shortest match for <b>pcre_dfa_exec()</b>
350 \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32)
351 \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin-
352 ated by next non-alphanumeric character)
353 \L call pcre_get_substringlist() after a successful match
354 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
355 \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
356 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
357 \P pass the PCRE_PARTIAL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
358 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
359 \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
360 \S output details of memory get/free calls during matching
361 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
362 \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
363 \&#62;dd start the match at offset dd (any number of digits);
364 this sets the <i>startoffset</i> argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
365 \&#60;cr&#62; pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
366 \&#60;lf&#62; pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
367 \&#60;crlf&#62; pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
368 \&#60;any&#62; pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
369 </pre>
370 The escapes that specify line ending sequences are literal strings, exactly as
371 shown. No more than one newline setting should be present in any data line.
372 </P>
373 <P>
374 A backslash followed by anything else just escapes the anything else. If
375 the very last character is a backslash, it is ignored. This gives a way of
376 passing an empty line as data, since a real empty line terminates the data
377 input.
378 </P>
379 <P>
380 If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
381 different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
382 fields of the <b>pcre_extra</b> data structure, until it finds the minimum
383 numbers for each parameter that allow <b>pcre_exec()</b> to complete. The
384 <i>match_limit</i> number is a measure of the amount of backtracking that takes
385 place, and checking it out can be instructive. For most simple matches, the
386 number is quite small, but for patterns with very large numbers of matching
387 possibilities, it can become large very quickly with increasing length of
388 subject string. The <i>match_limit_recursion</i> number is a measure of how much
389 stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed
390 to complete the match attempt.
391 </P>
392 <P>
393 When \O is used, the value specified may be higher or lower than the size set
394 by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
395 the call of <b>pcre_exec()</b> for the line in which it appears.
396 </P>
397 <P>
398 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
399 API to be used, the only option-setting sequences that have any effect are \B
400 and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to
401 <b>regexec()</b>.
402 </P>
403 <P>
404 The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
405 of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
406 any number of hexadecimal digits inside the braces. The result is from one to
407 six bytes, encoded according to the UTF-8 rules.
408 </P>
409 <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
410 <P>
411 By default, <b>pcretest</b> uses the standard PCRE matching function,
412 <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
413 alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
414 different way, and has some restrictions. The differences between the two
415 functions are described in the
416 <a href="pcrematching.html"><b>pcrematching</b></a>
417 documentation.
418 </P>
419 <P>
420 If a data line contains the \D escape sequence, or if the command line
421 contains the <b>-dfa</b> option, the alternative matching function is called.
422 This function finds all possible matches at a given point. If, however, the \F
423 escape sequence is present in the data line, it stops after the first match is
424 found. This is always the shortest possible match.
425 </P>
426 <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
427 <P>
428 This section describes the output when the normal matching function,
429 <b>pcre_exec()</b>, is being used.
430 </P>
431 <P>
432 When a match succeeds, pcretest outputs the list of captured substrings that
433 <b>pcre_exec()</b> returns, starting with number 0 for the string that matched
434 the whole pattern. Otherwise, it outputs "No match" or "Partial match"
435 when <b>pcre_exec()</b> returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PARTIAL,
436 respectively, and otherwise the PCRE negative error number. Here is an example
437 of an interactive <b>pcretest</b> run.
438 <pre>
439 $ pcretest
440 PCRE version 7.0 30-Nov-2006
442 re&#62; /^abc(\d+)/
443 data&#62; abc123
444 0: abc123
445 1: 123
446 data&#62; xyz
447 No match
448 </pre>
449 If the strings contain any non-printing characters, they are output as \0x
450 escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
451 pattern. See below for the definition of non-printing characters. If the
452 pattern has the <b>/+</b> modifier, the output for substring 0 is followed by
453 the the rest of the subject string, identified by "0+" like this:
454 <pre>
455 re&#62; /cat/+
456 data&#62; cataract
457 0: cat
458 0+ aract
459 </pre>
460 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
461 matching attempts are output in sequence, like this:
462 <pre>
463 re&#62; /\Bi(\w\w)/g
464 data&#62; Mississippi
465 0: iss
466 1: ss
467 0: iss
468 1: ss
469 0: ipp
470 1: pp
471 </pre>
472 "No match" is output only if the first match attempt fails.
473 </P>
474 <P>
475 If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
476 data line that is successfully matched, the substrings extracted by the
477 convenience functions are output with C, G, or L after the string number
478 instead of a colon. This is in addition to the normal full list. The string
479 length (that is, the return from the extraction function) is given in
480 parentheses after each string for <b>\C</b> and <b>\G</b>.
481 </P>
482 <P>
483 Note that whereas patterns can be continued over several lines (a plain "&#62;"
484 prompt is used for continuations), data lines may not. However newlines can be
485 included in data by means of the \n escape (or \r, \r\n, etc., depending on
486 the newline sequence setting).
487 </P>
489 <P>
490 When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
491 means of the \D escape sequence or the <b>-dfa</b> command line option), the
492 output consists of a list of all the matches that start at the first point in
493 the subject where there is at least one match. For example:
494 <pre>
495 re&#62; /(tang|tangerine|tan)/
496 data&#62; yellow tangerine\D
497 0: tangerine
498 1: tang
499 2: tan
500 </pre>
501 (Using the normal matching function on this data finds only "tang".) The
502 longest matching string is always given first (and numbered zero).
503 </P>
504 <P>
505 If <b>/g</b> is present on the pattern, the search for further matches resumes
506 at the end of the longest match. For example:
507 <pre>
508 re&#62; /(tang|tangerine|tan)/g
509 data&#62; yellow tangerine and tangy sultana\D
510 0: tangerine
511 1: tang
512 2: tan
513 0: tang
514 1: tan
515 0: tan
516 </pre>
517 Since the matching function does not support substring capture, the escape
518 sequences that are concerned with captured substrings are not relevant.
519 </P>
520 <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
521 <P>
522 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
523 indicating that the subject partially matched the pattern, you can restart the
524 match with additional subject data by means of the \R escape sequence. For
525 example:
526 <pre>
527 re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
528 data&#62; 23ja\P\D
529 Partial match: 23ja
530 data&#62; n05\R\D
531 0: n05
532 </pre>
533 For further information about partial matching, see the
534 <a href="pcrepartial.html"><b>pcrepartial</b></a>
535 documentation.
536 </P>
537 <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
538 <P>
539 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
540 is called during matching. This works with both matching functions. By default,
541 the called function displays the callout number, the start and current
542 positions in the text at the callout time, and the next pattern item to be
543 tested. For example, the output
544 <pre>
545 ---&#62;pqrabcdef
546 0 ^ ^ \d
547 </pre>
548 indicates that callout number 0 occurred for a match attempt starting at the
549 fourth character of the subject string, when the pointer was at the seventh
550 character of the data, and when the next pattern item was \d. Just one
551 circumflex is output if the start and current positions are the same.
552 </P>
553 <P>
554 Callouts numbered 255 are assumed to be automatic callouts, inserted as a
555 result of the <b>/C</b> pattern modifier. In this case, instead of showing the
556 callout number, the offset in the pattern, preceded by a plus, is output. For
557 example:
558 <pre>
559 re&#62; /\d?[A-E]\*/C
560 data&#62; E*
561 ---&#62;E*
562 +0 ^ \d?
563 +3 ^ [A-E]
564 +8 ^^ \*
565 +10 ^ ^
566 0: E*
567 </pre>
568 The callout function in <b>pcretest</b> returns zero (carry on matching) by
569 default, but you can use a \C item in a data line (as described above) to
570 change this.
571 </P>
572 <P>
573 Inserting callouts can be helpful when using <b>pcretest</b> to check
574 complicated regular expressions. For further information about callouts, see
575 the
576 <a href="pcrecallout.html"><b>pcrecallout</b></a>
577 documentation.
578 </P>
579 <br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
580 <P>
581 When <b>pcretest</b> is outputting text in the compiled version of a pattern,
582 bytes other than 32-126 are always treated as non-printing characters are are
583 therefore shown as hex escapes.
584 </P>
585 <P>
586 When <b>pcretest</b> is outputting text that is a matched part of a subject
587 string, it behaves in the same way, unless a different locale has been set for
588 the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
589 function to distinguish printing and non-printing characters.
590 </P>
591 <br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
592 <P>
593 The facilities described in this section are not available when the POSIX
594 inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
595 specified.
596 </P>
597 <P>
598 When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
599 compiled pattern to a file, by following the modifiers with &#62; and a file name.
600 For example:
601 <pre>
602 /pattern/im &#62;/some/file
603 </pre>
604 See the
605 <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
606 documentation for a discussion about saving and re-using compiled patterns.
607 </P>
608 <P>
609 The data that is written is binary. The first eight bytes are the length of the
610 compiled pattern data followed by the length of the optional study data, each
611 written as four bytes in big-endian order (most significant byte first). If
612 there is no study data (either the pattern was not studied, or studying did not
613 return any data), the second length is zero. The lengths are followed by an
614 exact copy of the compiled pattern. If there is additional study data, this
615 follows immediately after the compiled pattern. After writing the file,
616 <b>pcretest</b> expects to read a new pattern.
617 </P>
618 <P>
619 A saved pattern can be reloaded into <b>pcretest</b> by specifing &#60; and a file
620 name instead of a pattern. The name of the file must not contain a &#60; character,
621 as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by &#60;
622 characters.
623 For example:
624 <pre>
625 re&#62; &#60;/some/file
626 Compiled regex loaded from /some/file
627 No study data
628 </pre>
629 When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in
630 the usual way.
631 </P>
632 <P>
633 You can copy a file written by <b>pcretest</b> to a different host and reload it
634 there, even if the new host has opposite endianness to the one on which the
635 pattern was compiled. For example, you can compile on an i86 machine and run on
636 a SPARC machine.
637 </P>
638 <P>
639 File names for saving and reloading can be absolute or relative, but note that
640 the shell facility of expanding a file name that starts with a tilde (~) is not
641 available.
642 </P>
643 <P>
644 The ability to save and reload files in <b>pcretest</b> is intended for testing
645 and experimentation. It is not intended for production use because only a
646 single pattern can be written to a file. Furthermore, there is no facility for
647 supplying custom character tables for use with a reloaded pattern. If the
648 original pattern was compiled with custom tables, an attempt to match a subject
649 string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
650 Finally, if you attempt to load a file that is not in the correct format, the
651 result is undefined.
652 </P>
653 <br><a name="SEC13" href="#TOC1">SEE ALSO</a><br>
654 <P>
655 <b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3),
656 <b>pcrepartial</b>(d), <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3).
657 </P>
658 <br><a name="SEC14" href="#TOC1">AUTHOR</a><br>
659 <P>
660 Philip Hazel
661 <br>
662 University Computing Service
663 <br>
664 Cambridge CB2 3QH, England.
665 <br>
666 </P>
667 <br><a name="SEC15" href="#TOC1">REVISION</a><br>
668 <P>
669 Last updated: 06 March 2007
670 <br>
671 Copyright &copy; 1997-2007 University of Cambridge.
672 <br>
673 <p>
674 Return to the <a href="index.html">PCRE index page</a>.
675 </p>


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