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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">COMMAND LINE 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] [input file [output file]]</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. The input for <b>pcretest</b> is a sequence of regular expression
46 patterns and strings to be matched, as described below. The output shows the
47 result of each match. Options on the command line and the patterns control PCRE
48 options and exactly what is output.
49 </P>
50 <br><a name="SEC2" href="#TOC1">COMMAND LINE OPTIONS</a><br>
51 <P>
52 <b>-b</b>
53 Behave as if each pattern has the <b>/B</b> (show byte code) modifier; the
54 internal form is output after compilation.
55 </P>
56 <P>
57 <b>-C</b>
58 Output the version number of the PCRE library, and all available information
59 about the optional features that are included, and then exit.
60 </P>
61 <P>
62 <b>-d</b>
63 Behave as if each pattern has the <b>/D</b> (debug) modifier; the internal
64 form and information about the compiled pattern is output after compilation;
65 <b>-d</b> is equivalent to <b>-b -i</b>.
66 </P>
67 <P>
68 <b>-dfa</b>
69 Behave as if each data line contains the \D escape sequence; this causes the
70 alternative matching function, <b>pcre_dfa_exec()</b>, to be used instead of the
71 standard <b>pcre_exec()</b> function (more detail is given below).
72 </P>
73 <P>
74 <b>-help</b>
75 Output a brief summary these options and then exit.
76 </P>
77 <P>
78 <b>-i</b>
79 Behave as if each pattern has the <b>/I</b> modifier; information about the
80 compiled pattern is given after compilation.
81 </P>
82 <P>
83 <b>-M</b>
84 Behave as if each data line contains the \M escape sequence; this causes
85 PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by
86 calling <b>pcre_exec()</b> repeatedly with different limits.
87 </P>
88 <P>
89 <b>-m</b>
90 Output the size of each compiled pattern after it has been compiled. This is
91 equivalent to adding <b>/M</b> to each regular expression.
92 </P>
93 <P>
94 <b>-o</b> <i>osize</i>
95 Set the number of elements in the output vector that is used when calling
96 <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> to be <i>osize</i>. The default value
97 is 45, which is enough for 14 capturing subexpressions for <b>pcre_exec()</b> or
98 22 different matches for <b>pcre_dfa_exec()</b>. The vector size can be
99 changed for individual matching calls by including \O in the data line (see
100 below).
101 </P>
102 <P>
103 <b>-p</b>
104 Behave as if each pattern has the <b>/P</b> modifier; the POSIX wrapper API is
105 used to call PCRE. None of the other options has any effect when <b>-p</b> is
106 set.
107 </P>
108 <P>
109 <b>-q</b>
110 Do not output the version number of <b>pcretest</b> at the start of execution.
111 </P>
112 <P>
113 <b>-S</b> <i>size</i>
114 On Unix-like systems, set the size of the run-time stack to <i>size</i>
115 megabytes.
116 </P>
117 <P>
118 <b>-s</b> or <b>-s+</b>
119 Behave as if each pattern has the <b>/S</b> modifier; in other words, force each
120 pattern to be studied. If <b>-s+</b> is used, the PCRE_STUDY_JIT_COMPILE flag is
121 passed to <b>pcre_study()</b>, causing just-in-time optimization to be set up if
122 it is available. If the <b>/I</b> or <b>/D</b> option is present on a pattern
123 (requesting output about the compiled pattern), information about the result of
124 studying is not included when studying is caused only by <b>-s</b> and neither
125 <b>-i</b> nor <b>-d</b> is present on the command line. This behaviour means that
126 the output from tests that are run with and without <b>-s</b> should be
127 identical, except when options that output information about the actual running
128 of a match are set. The <b>-M</b>, <b>-t</b>, and <b>-tm</b> options, which give
129 information about resources used, are likely to produce different output with
130 and without <b>-s</b>. Output may also differ if the <b>/C</b> option is present
131 on an individual pattern. This uses callouts to trace the the matching process,
132 and this may be different between studied and non-studied patterns. If the
133 pattern contains (*MARK) items there may also be differences, for the same
134 reason. The <b>-s</b> command line option can be overridden for specific
135 patterns that should never be studied (see the <b>/S</b> pattern modifier
136 below).
137 </P>
138 <P>
139 <b>-t</b>
140 Run each compile, study, and match many times with a timer, and output
141 resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with
142 <b>-t</b>, because you will then get the size output a zillion times, and the
143 timing will be distorted. You can control the number of iterations that are
144 used for timing by following <b>-t</b> with a number (as a separate item on the
145 command line). For example, "-t 1000" would iterate 1000 times. The default is
146 to iterate 500000 times.
147 </P>
148 <P>
149 <b>-tm</b>
150 This is like <b>-t</b> except that it times only the matching phase, not the
151 compile or study phases.
152 </P>
153 <br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br>
154 <P>
155 If <b>pcretest</b> is given two filename arguments, it reads from the first and
156 writes to the second. If it is given only one filename argument, it reads from
157 that file and writes to stdout. Otherwise, it reads from stdin and writes to
158 stdout, and prompts for each line of input, using "re&#62;" to prompt for regular
159 expressions, and "data&#62;" to prompt for data lines.
160 </P>
161 <P>
162 When <b>pcretest</b> is built, a configuration option can specify that it should
163 be linked with the <b>libreadline</b> library. When this is done, if the input
164 is from a terminal, it is read using the <b>readline()</b> function. This
165 provides line-editing and history facilities. The output from the <b>-help</b>
166 option states whether or not <b>readline()</b> will be used.
167 </P>
168 <P>
169 The program handles any number of sets of input on a single input file. Each
170 set starts with a regular expression, and continues with any number of data
171 lines to be matched against the pattern.
172 </P>
173 <P>
174 Each data line is matched separately and independently. If you want to do
175 multi-line matches, you have to use the \n escape sequence (or \r or \r\n,
176 etc., depending on the newline setting) in a single line of input to encode the
177 newline sequences. There is no limit on the length of data lines; the input
178 buffer is automatically extended if it is too small.
179 </P>
180 <P>
181 An empty line signals the end of the data lines, at which point a new regular
182 expression is read. The regular expressions are given enclosed in any
183 non-alphanumeric delimiters other than backslash, for example:
184 <pre>
185 /(a|bc)x+yz/
186 </pre>
187 White space before the initial delimiter is ignored. A regular expression may
188 be continued over several input lines, in which case the newline characters are
189 included within it. It is possible to include the delimiter within the pattern
190 by escaping it, for example
191 <pre>
192 /abc\/def/
193 </pre>
194 If you do so, the escape and the delimiter form part of the pattern, but since
195 delimiters are always non-alphanumeric, this does not affect its interpretation.
196 If the terminating delimiter is immediately followed by a backslash, for
197 example,
198 <pre>
199 /abc/\
200 </pre>
201 then a backslash is added to the end of the pattern. This is done to provide a
202 way of testing the error condition that arises if a pattern finishes with a
203 backslash, because
204 <pre>
205 /abc\/
206 </pre>
207 is interpreted as the first line of a pattern that starts with "abc/", causing
208 pcretest to read the next line as a continuation of the regular expression.
209 </P>
210 <br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br>
211 <P>
212 A pattern may be followed by any number of modifiers, which are mostly single
213 characters. Following Perl usage, these are referred to below as, for example,
214 "the <b>/i</b> modifier", even though the delimiter of the pattern need not
215 always be a slash, and no slash is used when writing modifiers. White space may
216 appear between the final pattern delimiter and the first modifier, and between
217 the modifiers themselves.
218 </P>
219 <P>
220 The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
221 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
222 <b>pcre_compile()</b> is called. These four modifier letters have the same
223 effect as they do in Perl. For example:
224 <pre>
225 /caseless/i
226 </pre>
227 The following table shows additional modifiers for setting PCRE compile-time
228 options that do not correspond to anything in Perl:
229 <pre>
230 <b>/8</b> PCRE_UTF8
231 <b>/?</b> PCRE_NO_UTF8_CHECK
232 <b>/A</b> PCRE_ANCHORED
235 <b>/f</b> PCRE_FIRSTLINE
236 <b>/J</b> PCRE_DUPNAMES
238 <b>/U</b> PCRE_UNGREEDY
239 <b>/W</b> PCRE_UCP
240 <b>/X</b> PCRE_EXTRA
242 <b>/&#60;JS&#62;</b> PCRE_JAVASCRIPT_COMPAT
243 <b>/&#60;cr&#62;</b> PCRE_NEWLINE_CR
244 <b>/&#60;lf&#62;</b> PCRE_NEWLINE_LF
245 <b>/&#60;crlf&#62;</b> PCRE_NEWLINE_CRLF
246 <b>/&#60;anycrlf&#62;</b> PCRE_NEWLINE_ANYCRLF
247 <b>/&#60;any&#62;</b> PCRE_NEWLINE_ANY
248 <b>/&#60;bsr_anycrlf&#62;</b> PCRE_BSR_ANYCRLF
249 <b>/&#60;bsr_unicode&#62;</b> PCRE_BSR_UNICODE
250 </pre>
251 The modifiers that are enclosed in angle brackets are literal strings as shown,
252 including the angle brackets, but the letters within can be in either case.
253 This example sets multiline matching with CRLF as the line ending sequence:
254 <pre>
255 /^abc/m&#60;CRLF&#62;
256 </pre>
257 As well as turning on the PCRE_UTF8 option, the <b>/8</b> modifier also causes
258 any non-printing characters in output strings to be printed using the
259 \x{hh...} notation if they are valid UTF-8 sequences. Full details of the PCRE
260 options are given in the
261 <a href="pcreapi.html"><b>pcreapi</b></a>
262 documentation.
263 </P>
264 <br><b>
265 Finding all matches in a string
266 </b><br>
267 <P>
268 Searching for all possible matches within each subject string can be requested
269 by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
270 again to search the remainder of the subject string. The difference between
271 <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
272 <b>pcre_exec()</b> to start searching at a new point within the entire string
273 (which is in effect what Perl does), whereas the latter passes over a shortened
274 substring. This makes a difference to the matching process if the pattern
275 begins with a lookbehind assertion (including \b or \B).
276 </P>
277 <P>
278 If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an
279 empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
280 PCRE_ANCHORED flags set in order to search for another, non-empty, match at the
281 same point. If this second match fails, the start offset is advanced, and the
282 normal match is retried. This imitates the way Perl handles such cases when
283 using the <b>/g</b> modifier or the <b>split()</b> function. Normally, the start
284 offset is advanced by one character, but if the newline convention recognizes
285 CRLF as a newline, and the current character is CR followed by LF, an advance
286 of two is used.
287 </P>
288 <br><b>
289 Other modifiers
290 </b><br>
291 <P>
292 There are yet more modifiers for controlling the way <b>pcretest</b>
293 operates.
294 </P>
295 <P>
296 The <b>/+</b> modifier requests that as well as outputting the substring that
297 matched the entire pattern, <b>pcretest</b> should in addition output the
298 remainder of the subject string. This is useful for tests where the subject
299 contains multiple copies of the same substring. If the <b>+</b> modifier appears
300 twice, the same action is taken for captured substrings. In each case the
301 remainder is output on the following line with a plus character following the
302 capture number. Note that this modifier must not immediately follow the /S
303 modifier because /S+ has another meaning.
304 </P>
305 <P>
306 The <b>/=</b> modifier requests that the values of all potential captured
307 parentheses be output after a match by <b>pcre_exec()</b>. By default, only
308 those up to the highest one actually used in the match are output
309 (corresponding to the return code from <b>pcre_exec()</b>). Values in the
310 offsets vector corresponding to higher numbers should be set to -1, and these
311 are output as "&#60;unset&#62;". This modifier gives a way of checking that this is
312 happening.
313 </P>
314 <P>
315 The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
316 output a representation of the compiled byte code after compilation. Normally
317 this information contains length and offset values; however, if <b>/Z</b> is
318 also present, this data is replaced by spaces. This is a special feature for
319 use in the automatic test scripts; it ensures that the same output is generated
320 for different internal link sizes.
321 </P>
322 <P>
323 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
324 <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
325 </P>
326 <P>
327 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
328 fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
329 facility is for testing the feature in PCRE that allows it to execute patterns
330 that were compiled on a host with a different endianness. This feature is not
331 available when the POSIX interface to PCRE is being used, that is, when the
332 <b>/P</b> pattern modifier is specified. See also the section about saving and
333 reloading compiled patterns below.
334 </P>
335 <P>
336 The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
337 compiled pattern (whether it is anchored, has a fixed first character, and
338 so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
339 pattern. If the pattern is studied, the results of that are also output.
340 </P>
341 <P>
342 The <b>/K</b> modifier requests <b>pcretest</b> to show names from backtracking
343 control verbs that are returned from calls to <b>pcre_exec()</b>. It causes
344 <b>pcretest</b> to create a <b>pcre_extra</b> block if one has not already been
345 created by a call to <b>pcre_study()</b>, and to set the PCRE_EXTRA_MARK flag
346 and the <b>mark</b> field within it, every time that <b>pcre_exec()</b> is
347 called. If the variable that the <b>mark</b> field points to is non-NULL for a
348 match, non-match, or partial match, <b>pcretest</b> prints the string to which
349 it points. For a match, this is shown on a line by itself, tagged with "MK:".
350 For a non-match it is added to the message.
351 </P>
352 <P>
353 The <b>/L</b> modifier must be followed directly by the name of a locale, for
354 example,
355 <pre>
356 /pattern/Lfr_FR
357 </pre>
358 For this reason, it must be the last modifier. The given locale is set,
359 <b>pcre_maketables()</b> is called to build a set of character tables for the
360 locale, and this is then passed to <b>pcre_compile()</b> when compiling the
361 regular expression. Without an <b>/L</b> (or <b>/T</b>) modifier, NULL is passed
362 as the tables pointer; that is, <b>/L</b> applies only to the expression on
363 which it appears.
364 </P>
365 <P>
366 The <b>/M</b> modifier causes the size of memory block used to hold the compiled
367 pattern to be output. This does not include the size of the <b>pcre</b> block;
368 it is just the actual compiled data. If the pattern is successfully studied
369 with the PCRE_STUDY_JIT_COMPILE option, the size of the JIT compiled code is
370 also output.
371 </P>
372 <P>
373 If the <b>/S</b> modifier appears once, it causes <b>pcre_study()</b> to be
374 called after the expression has been compiled, and the results used when the
375 expression is matched. If <b>/S</b> appears twice, it suppresses studying, even
376 if it was requested externally by the <b>-s</b> command line option. This makes
377 it possible to specify that certain patterns are always studied, and others are
378 never studied, independently of <b>-s</b>. This feature is used in the test
379 files in a few cases where the output is different when the pattern is studied.
380 </P>
381 <P>
382 If the <b>/S</b> modifier is immediately followed by a + character, the call to
383 <b>pcre_study()</b> is made with the PCRE_STUDY_JIT_COMPILE option, requesting
384 just-in-time optimization support if it is available. Note that there is also a
385 <b>/+</b> modifier; it must not be given immediately after <b>/S</b> because this
386 will be misinterpreted. If JIT studying is successful, it will automatically be
387 used when <b>pcre_exec()</b> is run, except when incompatible run-time options
388 are specified. These include the partial matching options; a complete list is
389 given in the
390 <a href="pcrejit.html"><b>pcrejit</b></a>
391 documentation. See also the <b>\J</b> escape sequence below for a way of
392 setting the size of the JIT stack.
393 </P>
394 <P>
395 The <b>/T</b> modifier must be followed by a single digit. It causes a specific
396 set of built-in character tables to be passed to <b>pcre_compile()</b>. It is
397 used in the standard PCRE tests to check behaviour with different character
398 tables. The digit specifies the tables as follows:
399 <pre>
400 0 the default ASCII tables, as distributed in
401 pcre_chartables.c.dist
402 1 a set of tables defining ISO 8859 characters
403 </pre>
404 In table 1, some characters whose codes are greater than 128 are identified as
405 letters, digits, spaces, etc.
406 </P>
407 <br><b>
408 Using the POSIX wrapper API
409 </b><br>
410 <P>
411 The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
412 API rather than its native API. When <b>/P</b> is set, the following modifiers
413 set options for the <b>regcomp()</b> function:
414 <pre>
415 /i REG_ICASE
418 /s REG_DOTALL )
419 /U REG_UNGREEDY ) These options are not part of
420 /W REG_UCP ) the POSIX standard
421 /8 REG_UTF8 )
422 </pre>
423 The <b>/+</b> modifier works as described above. All other modifiers are
424 ignored.
425 </P>
426 <br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
427 <P>
428 Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
429 white space is removed, and it is then scanned for \ escapes. Some of these
430 are pretty esoteric features, intended for checking out some of the more
431 complicated features of PCRE. If you are just testing "ordinary" regular
432 expressions, you probably don't need any of these. The following escapes are
433 recognized:
434 <pre>
435 \a alarm (BEL, \x07)
436 \b backspace (\x08)
437 \e escape (\x27)
438 \f form feed (\x0c)
439 \n newline (\x0a)
440 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
441 \r carriage return (\x0d)
442 \t tab (\x09)
443 \v vertical tab (\x0b)
444 \nnn octal character (up to 3 octal digits)
445 always a byte unless &#62; 255 in UTF-8 mode
446 \xhh hexadecimal byte (up to 2 hex digits)
447 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode
448 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
449 \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
450 \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32)
451 \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
452 ated by next non alphanumeric character)
453 \C+ show the current captured substrings at callout time
454 \C- do not supply a callout function
455 \C!n return 1 instead of 0 when callout number n is reached
456 \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
457 \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
458 \D use the <b>pcre_dfa_exec()</b> match function
459 \F only shortest match for <b>pcre_dfa_exec()</b>
460 \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32)
461 \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin-
462 ated by next non-alphanumeric character)
463 \Jdd set up a JIT stack of dd kilobytes maximum (any number of digits)
464 \L call pcre_get_substringlist() after a successful match
465 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
466 \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the
468 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
469 \P pass the PCRE_PARTIAL_SOFT option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the
471 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
472 \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
473 \S output details of memory get/free calls during matching
474 \Y pass the PCRE_NO_START_OPTIMIZE option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
475 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
476 \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
477 \&#62;dd start the match at offset dd (optional "-"; then any number of digits); this sets the <i>startoffset</i>
478 argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
479 \&#60;cr&#62; pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
480 \&#60;lf&#62; pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
481 \&#60;crlf&#62; pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
482 \&#60;anycrlf&#62; pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
483 \&#60;any&#62; pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
484 </pre>
485 Note that \xhh always specifies one byte, even in UTF-8 mode; this makes it
486 possible to construct invalid UTF-8 sequences for testing purposes. On the
487 other hand, \x{hh} is interpreted as a UTF-8 character in UTF-8 mode,
488 generating more than one byte if the value is greater than 127. When not in
489 UTF-8 mode, it generates one byte for values less than 256, and causes an error
490 for greater values.
491 </P>
492 <P>
493 The escapes that specify line ending sequences are literal strings, exactly as
494 shown. No more than one newline setting should be present in any data line.
495 </P>
496 <P>
497 A backslash followed by anything else just escapes the anything else. If
498 the very last character is a backslash, it is ignored. This gives a way of
499 passing an empty line as data, since a real empty line terminates the data
500 input.
501 </P>
502 <P>
503 The <b>\J</b> escape provides a way of setting the maximum stack size that is
504 used by the just-in-time optimization code. It is ignored if JIT optimization
505 is not being used. Providing a stack that is larger than the default 32K is
506 necessary only for very complicated patterns.
507 </P>
508 <P>
509 If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
510 different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
511 fields of the <b>pcre_extra</b> data structure, until it finds the minimum
512 numbers for each parameter that allow <b>pcre_exec()</b> to complete without
513 error. Because this is testing a specific feature of the normal interpretive
514 <b>pcre_exec()</b> execution, the use of any JIT optimization that might have
515 been set up by the <b>/S+</b> qualifier of <b>-s+</b> option is disabled.
516 </P>
517 <P>
518 The <i>match_limit</i> number is a measure of the amount of backtracking
519 that takes place, and checking it out can be instructive. For most simple
520 matches, the number is quite small, but for patterns with very large numbers of
521 matching possibilities, it can become large very quickly with increasing length
522 of subject string. The <i>match_limit_recursion</i> number is a measure of how
523 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is
524 needed to complete the match attempt.
525 </P>
526 <P>
527 When \O is used, the value specified may be higher or lower than the size set
528 by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
529 the call of <b>pcre_exec()</b> for the line in which it appears.
530 </P>
531 <P>
532 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
533 API to be used, the only option-setting sequences that have any effect are \B,
534 \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,
535 to be passed to <b>regexec()</b>.
536 </P>
537 <P>
538 The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
539 of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
540 any number of hexadecimal digits inside the braces. The result is from one to
541 six bytes, encoded according to the original UTF-8 rules of RFC 2279. This
542 allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are
543 valid Unicode code points, or indeed valid UTF-8 characters according to the
544 later rules in RFC 3629.
545 </P>
546 <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
547 <P>
548 By default, <b>pcretest</b> uses the standard PCRE matching function,
549 <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
550 alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
551 different way, and has some restrictions. The differences between the two
552 functions are described in the
553 <a href="pcrematching.html"><b>pcrematching</b></a>
554 documentation.
555 </P>
556 <P>
557 If a data line contains the \D escape sequence, or if the command line
558 contains the <b>-dfa</b> option, the alternative matching function is called.
559 This function finds all possible matches at a given point. If, however, the \F
560 escape sequence is present in the data line, it stops after the first match is
561 found. This is always the shortest possible match.
562 </P>
563 <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
564 <P>
565 This section describes the output when the normal matching function,
566 <b>pcre_exec()</b>, is being used.
567 </P>
568 <P>
569 When a match succeeds, <b>pcretest</b> outputs the list of captured substrings
570 that <b>pcre_exec()</b> returns, starting with number 0 for the string that
571 matched the whole pattern. Otherwise, it outputs "No match" when the return is
572 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
573 substring when <b>pcre_exec()</b> returns PCRE_ERROR_PARTIAL. (Note that this is
574 the entire substring that was inspected during the partial match; it may
575 include characters before the actual match start if a lookbehind assertion,
576 \K, \b, or \B was involved.) For any other return, <b>pcretest</b> outputs
577 the PCRE negative error number and a short descriptive phrase. If the error is
578 a failed UTF-8 string check, the byte offset of the start of the failing
579 character and the reason code are also output, provided that the size of the
580 output vector is at least two. Here is an example of an interactive
581 <b>pcretest</b> run.
582 <pre>
583 $ pcretest
584 PCRE version 8.13 2011-04-30
586 re&#62; /^abc(\d+)/
587 data&#62; abc123
588 0: abc123
589 1: 123
590 data&#62; xyz
591 No match
592 </pre>
593 Unset capturing substrings that are not followed by one that is set are not
594 returned by <b>pcre_exec()</b>, and are not shown by <b>pcretest</b>. In the
595 following example, there are two capturing substrings, but when the first data
596 line is matched, the second, unset substring is not shown. An "internal" unset
597 substring is shown as "&#60;unset&#62;", as for the second data line.
598 <pre>
599 re&#62; /(a)|(b)/
600 data&#62; a
601 0: a
602 1: a
603 data&#62; b
604 0: b
605 1: &#60;unset&#62;
606 2: b
607 </pre>
608 If the strings contain any non-printing characters, they are output as \0x
609 escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
610 pattern. See below for the definition of non-printing characters. If the
611 pattern has the <b>/+</b> modifier, the output for substring 0 is followed by
612 the the rest of the subject string, identified by "0+" like this:
613 <pre>
614 re&#62; /cat/+
615 data&#62; cataract
616 0: cat
617 0+ aract
618 </pre>
619 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
620 matching attempts are output in sequence, like this:
621 <pre>
622 re&#62; /\Bi(\w\w)/g
623 data&#62; Mississippi
624 0: iss
625 1: ss
626 0: iss
627 1: ss
628 0: ipp
629 1: pp
630 </pre>
631 "No match" is output only if the first match attempt fails. Here is an example
632 of a failure message (the offset 4 that is specified by \&#62;4 is past the end of
633 the subject string):
634 <pre>
635 re&#62; /xyz/
636 data&#62; xyz\&#62;4
637 Error -24 (bad offset value)
638 </PRE>
639 </P>
640 <P>
641 If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
642 data line that is successfully matched, the substrings extracted by the
643 convenience functions are output with C, G, or L after the string number
644 instead of a colon. This is in addition to the normal full list. The string
645 length (that is, the return from the extraction function) is given in
646 parentheses after each string for <b>\C</b> and <b>\G</b>.
647 </P>
648 <P>
649 Note that whereas patterns can be continued over several lines (a plain "&#62;"
650 prompt is used for continuations), data lines may not. However newlines can be
651 included in data by means of the \n escape (or \r, \r\n, etc., depending on
652 the newline sequence setting).
653 </P>
655 <P>
656 When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
657 means of the \D escape sequence or the <b>-dfa</b> command line option), the
658 output consists of a list of all the matches that start at the first point in
659 the subject where there is at least one match. For example:
660 <pre>
661 re&#62; /(tang|tangerine|tan)/
662 data&#62; yellow tangerine\D
663 0: tangerine
664 1: tang
665 2: tan
666 </pre>
667 (Using the normal matching function on this data finds only "tang".) The
668 longest matching string is always given first (and numbered zero). After a
669 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
670 partially matching substring. (Note that this is the entire substring that was
671 inspected during the partial match; it may include characters before the actual
672 match start if a lookbehind assertion, \K, \b, or \B was involved.)
673 </P>
674 <P>
675 If <b>/g</b> is present on the pattern, the search for further matches resumes
676 at the end of the longest match. For example:
677 <pre>
678 re&#62; /(tang|tangerine|tan)/g
679 data&#62; yellow tangerine and tangy sultana\D
680 0: tangerine
681 1: tang
682 2: tan
683 0: tang
684 1: tan
685 0: tan
686 </pre>
687 Since the matching function does not support substring capture, the escape
688 sequences that are concerned with captured substrings are not relevant.
689 </P>
690 <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
691 <P>
692 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
693 indicating that the subject partially matched the pattern, you can restart the
694 match with additional subject data by means of the \R escape sequence. For
695 example:
696 <pre>
697 re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
698 data&#62; 23ja\P\D
699 Partial match: 23ja
700 data&#62; n05\R\D
701 0: n05
702 </pre>
703 For further information about partial matching, see the
704 <a href="pcrepartial.html"><b>pcrepartial</b></a>
705 documentation.
706 </P>
707 <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
708 <P>
709 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
710 is called during matching. This works with both matching functions. By default,
711 the called function displays the callout number, the start and current
712 positions in the text at the callout time, and the next pattern item to be
713 tested. For example, the output
714 <pre>
715 ---&#62;pqrabcdef
716 0 ^ ^ \d
717 </pre>
718 indicates that callout number 0 occurred for a match attempt starting at the
719 fourth character of the subject string, when the pointer was at the seventh
720 character of the data, and when the next pattern item was \d. Just one
721 circumflex is output if the start and current positions are the same.
722 </P>
723 <P>
724 Callouts numbered 255 are assumed to be automatic callouts, inserted as a
725 result of the <b>/C</b> pattern modifier. In this case, instead of showing the
726 callout number, the offset in the pattern, preceded by a plus, is output. For
727 example:
728 <pre>
729 re&#62; /\d?[A-E]\*/C
730 data&#62; E*
731 ---&#62;E*
732 +0 ^ \d?
733 +3 ^ [A-E]
734 +8 ^^ \*
735 +10 ^ ^
736 0: E*
737 </pre>
738 If a pattern contains (*MARK) items, an additional line is output whenever
739 a change of latest mark is passed to the callout function. For example:
740 <pre>
741 re&#62; /a(*MARK:X)bc/C
742 data&#62; abc
743 ---&#62;abc
744 +0 ^ a
745 +1 ^^ (*MARK:X)
746 +10 ^^ b
747 Latest Mark: X
748 +11 ^ ^ c
749 +12 ^ ^
750 0: abc
751 </pre>
752 The mark changes between matching "a" and "b", but stays the same for the rest
753 of the match, so nothing more is output. If, as a result of backtracking, the
754 mark reverts to being unset, the text "&#60;unset&#62;" is output.
755 </P>
756 <P>
757 The callout function in <b>pcretest</b> returns zero (carry on matching) by
758 default, but you can use a \C item in a data line (as described above) to
759 change this and other parameters of the callout.
760 </P>
761 <P>
762 Inserting callouts can be helpful when using <b>pcretest</b> to check
763 complicated regular expressions. For further information about callouts, see
764 the
765 <a href="pcrecallout.html"><b>pcrecallout</b></a>
766 documentation.
767 </P>
768 <br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
769 <P>
770 When <b>pcretest</b> is outputting text in the compiled version of a pattern,
771 bytes other than 32-126 are always treated as non-printing characters are are
772 therefore shown as hex escapes.
773 </P>
774 <P>
775 When <b>pcretest</b> is outputting text that is a matched part of a subject
776 string, it behaves in the same way, unless a different locale has been set for
777 the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
778 function to distinguish printing and non-printing characters.
779 </P>
780 <br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
781 <P>
782 The facilities described in this section are not available when the POSIX
783 interface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
784 specified.
785 </P>
786 <P>
787 When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
788 compiled pattern to a file, by following the modifiers with &#62; and a file name.
789 For example:
790 <pre>
791 /pattern/im &#62;/some/file
792 </pre>
793 See the
794 <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
795 documentation for a discussion about saving and re-using compiled patterns.
796 Note that if the pattern was successfully studied with JIT optimization, the
797 JIT data cannot be saved.
798 </P>
799 <P>
800 The data that is written is binary. The first eight bytes are the length of the
801 compiled pattern data followed by the length of the optional study data, each
802 written as four bytes in big-endian order (most significant byte first). If
803 there is no study data (either the pattern was not studied, or studying did not
804 return any data), the second length is zero. The lengths are followed by an
805 exact copy of the compiled pattern. If there is additional study data, this
806 (excluding any JIT data) follows immediately after the compiled pattern. After
807 writing the file, <b>pcretest</b> expects to read a new pattern.
808 </P>
809 <P>
810 A saved pattern can be reloaded into <b>pcretest</b> by specifying &#60; and a file
811 name instead of a pattern. The name of the file must not contain a &#60; character,
812 as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by &#60;
813 characters.
814 For example:
815 <pre>
816 re&#62; &#60;/some/file
817 Compiled pattern loaded from /some/file
818 No study data
819 </pre>
820 If the pattern was previously studied with the JIT optimization, the JIT
821 information cannot be saved and restored, and so is lost. When the pattern has
822 been loaded, <b>pcretest</b> proceeds to read data lines in the usual way.
823 </P>
824 <P>
825 You can copy a file written by <b>pcretest</b> to a different host and reload it
826 there, even if the new host has opposite endianness to the one on which the
827 pattern was compiled. For example, you can compile on an i86 machine and run on
828 a SPARC machine.
829 </P>
830 <P>
831 File names for saving and reloading can be absolute or relative, but note that
832 the shell facility of expanding a file name that starts with a tilde (~) is not
833 available.
834 </P>
835 <P>
836 The ability to save and reload files in <b>pcretest</b> is intended for testing
837 and experimentation. It is not intended for production use because only a
838 single pattern can be written to a file. Furthermore, there is no facility for
839 supplying custom character tables for use with a reloaded pattern. If the
840 original pattern was compiled with custom tables, an attempt to match a subject
841 string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
842 Finally, if you attempt to load a file that is not in the correct format, the
843 result is undefined.
844 </P>
845 <br><a name="SEC13" href="#TOC1">SEE ALSO</a><br>
846 <P>
847 <b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrejit</b>,
848 <b>pcrematching</b>(3), <b>pcrepartial</b>(d), <b>pcrepattern</b>(3),
849 <b>pcreprecompile</b>(3).
850 </P>
851 <br><a name="SEC14" href="#TOC1">AUTHOR</a><br>
852 <P>
853 Philip Hazel
854 <br>
855 University Computing Service
856 <br>
857 Cambridge CB2 3QH, England.
858 <br>
859 </P>
860 <br><a name="SEC15" href="#TOC1">REVISION</a><br>
861 <P>
862 Last updated: 02 December 2011
863 <br>
864 Copyright &copy; 1997-2011 University of Cambridge.
865 <br>
866 <p>
867 Return to the <a href="index.html">PCRE index page</a>.
868 </p>


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