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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">PCRE's 8-BIT and 16-BIT LIBRARIES</a>
18 <li><a name="TOC3" href="#SEC3">COMMAND LINE OPTIONS</a>
19 <li><a name="TOC4" href="#SEC4">DESCRIPTION</a>
20 <li><a name="TOC5" href="#SEC5">PATTERN MODIFIERS</a>
21 <li><a name="TOC6" href="#SEC6">DATA LINES</a>
22 <li><a name="TOC7" href="#SEC7">THE ALTERNATIVE MATCHING FUNCTION</a>
23 <li><a name="TOC8" href="#SEC8">DEFAULT OUTPUT FROM PCRETEST</a>
24 <li><a name="TOC9" href="#SEC9">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a>
25 <li><a name="TOC10" href="#SEC10">RESTARTING AFTER A PARTIAL MATCH</a>
26 <li><a name="TOC11" href="#SEC11">CALLOUTS</a>
27 <li><a name="TOC12" href="#SEC12">NON-PRINTING CHARACTERS</a>
28 <li><a name="TOC13" href="#SEC13">SAVING AND RELOADING COMPILED PATTERNS</a>
29 <li><a name="TOC14" href="#SEC14">SEE ALSO</a>
30 <li><a name="TOC15" href="#SEC15">AUTHOR</a>
31 <li><a name="TOC16" href="#SEC16">REVISION</a>
32 </ul>
33 <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
34 <P>
35 <b>pcretest [options] [input file [output file]]</b>
36 <br>
37 <br>
38 <b>pcretest</b> was written as a test program for the PCRE regular expression
39 library itself, but it can also be used for experimenting with regular
40 expressions. This document describes the features of the test program; for
41 details of the regular expressions themselves, see the
42 <a href="pcrepattern.html"><b>pcrepattern</b></a>
43 documentation. For details of the PCRE library function calls and their
44 options, see the
45 <a href="pcreapi.html"><b>pcreapi</b></a>
46 and
47 <a href="pcre16.html"><b>pcre16</b></a>
48 documentation. The input for <b>pcretest</b> is a sequence of regular expression
49 patterns and strings to be matched, as described below. The output shows the
50 result of each match. Options on the command line and the patterns control PCRE
51 options and exactly what is output.
52 </P>
53 <br><a name="SEC2" href="#TOC1">PCRE's 8-BIT and 16-BIT LIBRARIES</a><br>
54 <P>
55 From release 8.30, two separate PCRE libraries can be built. The original one
56 supports 8-bit character strings, whereas the newer 16-bit library supports
57 character strings encoded in 16-bit units. The <b>pcretest</b> program can be
58 used to test both libraries. However, it is itself still an 8-bit program,
59 reading 8-bit input and writing 8-bit output. When testing the 16-bit library,
60 the patterns and data strings are converted to 16-bit format before being
61 passed to the PCRE library functions. Results are converted to 8-bit for
62 output.
63 </P>
64 <P>
65 References to functions and structures of the form <b>pcre[16]_xx</b> below
66 mean "<b>pcre_xx</b> when using the 8-bit library or <b>pcre16_xx</b> when using
67 the 16-bit library".
68 </P>
69 <br><a name="SEC3" href="#TOC1">COMMAND LINE OPTIONS</a><br>
70 <P>
71 <b>-16</b>
72 If both the 8-bit and the 16-bit libraries have been built, this option causes
73 the 16-bit library to be used. If only the 16-bit library has been built, this
74 is the default (so has no effect). If only the 8-bit library has been built,
75 this option causes an error.
76 </P>
77 <P>
78 <b>-b</b>
79 Behave as if each pattern has the <b>/B</b> (show byte code) modifier; the
80 internal form is output after compilation.
81 </P>
82 <P>
83 <b>-C</b>
84 Output the version number of the PCRE library, and all available information
85 about the optional features that are included, and then exit. All other options
86 are ignored.
87 </P>
88 <P>
89 <b>-C</b> <i>option</i>
90 Output information about a specific build-time option, then exit. This
91 functionality is intended for use in scripts such as <b>RunTest</b>. The
92 following options output the value indicated:
93 <pre>
94 linksize the internal link size (2, 3, or 4)
95 newline the default newline setting:
96 CR, LF, CRLF, ANYCRLF, or ANY
97 </pre>
98 The following options output 1 for true or zero for false:
99 <pre>
100 jit just-in-time support is available
101 pcre16 the 16-bit library was built
102 pcre8 the 8-bit library was built
103 ucp Unicode property support is available
104 utf UTF-8 and/or UTF-16 support is available
105 </PRE>
106 </P>
107 <P>
108 <b>-d</b>
109 Behave as if each pattern has the <b>/D</b> (debug) modifier; the internal
110 form and information about the compiled pattern is output after compilation;
111 <b>-d</b> is equivalent to <b>-b -i</b>.
112 </P>
113 <P>
114 <b>-dfa</b>
115 Behave as if each data line contains the \D escape sequence; this causes the
116 alternative matching function, <b>pcre[16]_dfa_exec()</b>, to be used instead of
117 the standard <b>pcre[16]_exec()</b> function (more detail is given below).
118 </P>
119 <P>
120 <b>-help</b>
121 Output a brief summary these options and then exit.
122 </P>
123 <P>
124 <b>-i</b>
125 Behave as if each pattern has the <b>/I</b> modifier; information about the
126 compiled pattern is given after compilation.
127 </P>
128 <P>
129 <b>-M</b>
130 Behave as if each data line contains the \M escape sequence; this causes
131 PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by
132 calling <b>pcre[16]_exec()</b> repeatedly with different limits.
133 </P>
134 <P>
135 <b>-m</b>
136 Output the size of each compiled pattern after it has been compiled. This is
137 equivalent to adding <b>/M</b> to each regular expression. The size is given in
138 bytes for both libraries.
139 </P>
140 <P>
141 <b>-o</b> <i>osize</i>
142 Set the number of elements in the output vector that is used when calling
143 <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b> to be <i>osize</i>. The
144 default value is 45, which is enough for 14 capturing subexpressions for
145 <b>pcre[16]_exec()</b> or 22 different matches for <b>pcre[16]_dfa_exec()</b>.
146 The vector size can be changed for individual matching calls by including \O
147 in the data line (see below).
148 </P>
149 <P>
150 <b>-p</b>
151 Behave as if each pattern has the <b>/P</b> modifier; the POSIX wrapper API is
152 used to call PCRE. None of the other options has any effect when <b>-p</b> is
153 set. This option can be used only with the 8-bit library.
154 </P>
155 <P>
156 <b>-q</b>
157 Do not output the version number of <b>pcretest</b> at the start of execution.
158 </P>
159 <P>
160 <b>-S</b> <i>size</i>
161 On Unix-like systems, set the size of the run-time stack to <i>size</i>
162 megabytes.
163 </P>
164 <P>
165 <b>-s</b> or <b>-s+</b>
166 Behave as if each pattern has the <b>/S</b> modifier; in other words, force each
167 pattern to be studied. If <b>-s+</b> is used, all the JIT compile options are
168 passed to <b>pcre[16]_study()</b>, causing just-in-time optimization to be set
169 up if it is available, for both full and partial matching. Specific JIT compile
170 options can be selected by following <b>-s+</b> with a digit in the range 1 to
171 7, which selects the JIT compile modes as follows:
172 <pre>
173 1 normal match only
174 2 soft partial match only
175 3 normal match and soft partial match
176 4 hard partial match only
177 6 soft and hard partial match
178 7 all three modes (default)
179 </pre>
180 If <b>-s++</b> is used instead of <b>-s+</b> (with or without a following digit),
181 the text "(JIT)" is added to the first output line after a match or no match
182 when JIT-compiled code was actually used.
183 </P>
184 <P>
185 If the <b>/I</b> or <b>/D</b> option is present on a pattern (requesting output
186 about the compiled pattern), information about the result of studying is not
187 included when studying is caused only by <b>-s</b> and neither <b>-i</b> nor
188 <b>-d</b> is present on the command line. This behaviour means that the output
189 from tests that are run with and without <b>-s</b> should be identical, except
190 when options that output information about the actual running of a match are
191 set.
192 <br>
193 <br>
194 The <b>-M</b>, <b>-t</b>, and <b>-tm</b> options, which give information about
195 resources used, are likely to produce different output with and without
196 <b>-s</b>. Output may also differ if the <b>/C</b> option is present on an
197 individual pattern. This uses callouts to trace the the matching process, and
198 this may be different between studied and non-studied patterns. If the pattern
199 contains (*MARK) items there may also be differences, for the same reason. The
200 <b>-s</b> command line option can be overridden for specific patterns that
201 should never be studied (see the <b>/S</b> pattern modifier below).
202 </P>
203 <P>
204 <b>-t</b>
205 Run each compile, study, and match many times with a timer, and output
206 resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with
207 <b>-t</b>, because you will then get the size output a zillion times, and the
208 timing will be distorted. You can control the number of iterations that are
209 used for timing by following <b>-t</b> with a number (as a separate item on the
210 command line). For example, "-t 1000" would iterate 1000 times. The default is
211 to iterate 500000 times.
212 </P>
213 <P>
214 <b>-tm</b>
215 This is like <b>-t</b> except that it times only the matching phase, not the
216 compile or study phases.
217 </P>
218 <br><a name="SEC4" href="#TOC1">DESCRIPTION</a><br>
219 <P>
220 If <b>pcretest</b> is given two filename arguments, it reads from the first and
221 writes to the second. If it is given only one filename argument, it reads from
222 that file and writes to stdout. Otherwise, it reads from stdin and writes to
223 stdout, and prompts for each line of input, using "re&#62;" to prompt for regular
224 expressions, and "data&#62;" to prompt for data lines.
225 </P>
226 <P>
227 When <b>pcretest</b> is built, a configuration option can specify that it should
228 be linked with the <b>libreadline</b> library. When this is done, if the input
229 is from a terminal, it is read using the <b>readline()</b> function. This
230 provides line-editing and history facilities. The output from the <b>-help</b>
231 option states whether or not <b>readline()</b> will be used.
232 </P>
233 <P>
234 The program handles any number of sets of input on a single input file. Each
235 set starts with a regular expression, and continues with any number of data
236 lines to be matched against the pattern.
237 </P>
238 <P>
239 Each data line is matched separately and independently. If you want to do
240 multi-line matches, you have to use the \n escape sequence (or \r or \r\n,
241 etc., depending on the newline setting) in a single line of input to encode the
242 newline sequences. There is no limit on the length of data lines; the input
243 buffer is automatically extended if it is too small.
244 </P>
245 <P>
246 An empty line signals the end of the data lines, at which point a new regular
247 expression is read. The regular expressions are given enclosed in any
248 non-alphanumeric delimiters other than backslash, for example:
249 <pre>
250 /(a|bc)x+yz/
251 </pre>
252 White space before the initial delimiter is ignored. A regular expression may
253 be continued over several input lines, in which case the newline characters are
254 included within it. It is possible to include the delimiter within the pattern
255 by escaping it, for example
256 <pre>
257 /abc\/def/
258 </pre>
259 If you do so, the escape and the delimiter form part of the pattern, but since
260 delimiters are always non-alphanumeric, this does not affect its interpretation.
261 If the terminating delimiter is immediately followed by a backslash, for
262 example,
263 <pre>
264 /abc/\
265 </pre>
266 then a backslash is added to the end of the pattern. This is done to provide a
267 way of testing the error condition that arises if a pattern finishes with a
268 backslash, because
269 <pre>
270 /abc\/
271 </pre>
272 is interpreted as the first line of a pattern that starts with "abc/", causing
273 pcretest to read the next line as a continuation of the regular expression.
274 </P>
275 <br><a name="SEC5" href="#TOC1">PATTERN MODIFIERS</a><br>
276 <P>
277 A pattern may be followed by any number of modifiers, which are mostly single
278 characters. Following Perl usage, these are referred to below as, for example,
279 "the <b>/i</b> modifier", even though the delimiter of the pattern need not
280 always be a slash, and no slash is used when writing modifiers. White space may
281 appear between the final pattern delimiter and the first modifier, and between
282 the modifiers themselves.
283 </P>
284 <P>
285 The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
286 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
287 <b>pcre[16]_compile()</b> is called. These four modifier letters have the same
288 effect as they do in Perl. For example:
289 <pre>
290 /caseless/i
291 </pre>
292 The following table shows additional modifiers for setting PCRE compile-time
293 options that do not correspond to anything in Perl:
294 <pre>
295 <b>/8</b> PCRE_UTF8 ) when using the 8-bit
296 <b>/?</b> PCRE_NO_UTF8_CHECK ) library
297
298 <b>/8</b> PCRE_UTF16 ) when using the 16-bit
299 <b>/?</b> PCRE_NO_UTF16_CHECK ) library
300
301 <b>/A</b> PCRE_ANCHORED
302 <b>/C</b> PCRE_AUTO_CALLOUT
303 <b>/E</b> PCRE_DOLLAR_ENDONLY
304 <b>/f</b> PCRE_FIRSTLINE
305 <b>/J</b> PCRE_DUPNAMES
306 <b>/N</b> PCRE_NO_AUTO_CAPTURE
307 <b>/U</b> PCRE_UNGREEDY
308 <b>/W</b> PCRE_UCP
309 <b>/X</b> PCRE_EXTRA
310 <b>/Y</b> PCRE_NO_START_OPTIMIZE
311 <b>/&#60;JS&#62;</b> PCRE_JAVASCRIPT_COMPAT
312 <b>/&#60;cr&#62;</b> PCRE_NEWLINE_CR
313 <b>/&#60;lf&#62;</b> PCRE_NEWLINE_LF
314 <b>/&#60;crlf&#62;</b> PCRE_NEWLINE_CRLF
315 <b>/&#60;anycrlf&#62;</b> PCRE_NEWLINE_ANYCRLF
316 <b>/&#60;any&#62;</b> PCRE_NEWLINE_ANY
317 <b>/&#60;bsr_anycrlf&#62;</b> PCRE_BSR_ANYCRLF
318 <b>/&#60;bsr_unicode&#62;</b> PCRE_BSR_UNICODE
319 </pre>
320 The modifiers that are enclosed in angle brackets are literal strings as shown,
321 including the angle brackets, but the letters within can be in either case.
322 This example sets multiline matching with CRLF as the line ending sequence:
323 <pre>
324 /^abc/m&#60;CRLF&#62;
325 </pre>
326 As well as turning on the PCRE_UTF8/16 option, the <b>/8</b> modifier causes
327 all non-printing characters in output strings to be printed using the
328 \x{hh...} notation. Otherwise, those less than 0x100 are output in hex without
329 the curly brackets.
330 </P>
331 <P>
332 Full details of the PCRE options are given in the
333 <a href="pcreapi.html"><b>pcreapi</b></a>
334 documentation.
335 </P>
336 <br><b>
337 Finding all matches in a string
338 </b><br>
339 <P>
340 Searching for all possible matches within each subject string can be requested
341 by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
342 again to search the remainder of the subject string. The difference between
343 <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
344 <b>pcre[16]_exec()</b> to start searching at a new point within the entire
345 string (which is in effect what Perl does), whereas the latter passes over a
346 shortened substring. This makes a difference to the matching process if the
347 pattern begins with a lookbehind assertion (including \b or \B).
348 </P>
349 <P>
350 If any call to <b>pcre[16]_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches
351 an empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
352 PCRE_ANCHORED flags set in order to search for another, non-empty, match at the
353 same point. If this second match fails, the start offset is advanced, and the
354 normal match is retried. This imitates the way Perl handles such cases when
355 using the <b>/g</b> modifier or the <b>split()</b> function. Normally, the start
356 offset is advanced by one character, but if the newline convention recognizes
357 CRLF as a newline, and the current character is CR followed by LF, an advance
358 of two is used.
359 </P>
360 <br><b>
361 Other modifiers
362 </b><br>
363 <P>
364 There are yet more modifiers for controlling the way <b>pcretest</b>
365 operates.
366 </P>
367 <P>
368 The <b>/+</b> modifier requests that as well as outputting the substring that
369 matched the entire pattern, <b>pcretest</b> should in addition output the
370 remainder of the subject string. This is useful for tests where the subject
371 contains multiple copies of the same substring. If the <b>+</b> modifier appears
372 twice, the same action is taken for captured substrings. In each case the
373 remainder is output on the following line with a plus character following the
374 capture number. Note that this modifier must not immediately follow the /S
375 modifier because /S+ and /S++ have other meanings.
376 </P>
377 <P>
378 The <b>/=</b> modifier requests that the values of all potential captured
379 parentheses be output after a match. By default, only those up to the highest
380 one actually used in the match are output (corresponding to the return code
381 from <b>pcre[16]_exec()</b>). Values in the offsets vector corresponding to
382 higher numbers should be set to -1, and these are output as "&#60;unset&#62;". This
383 modifier gives a way of checking that this is happening.
384 </P>
385 <P>
386 The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
387 output a representation of the compiled code after compilation. Normally this
388 information contains length and offset values; however, if <b>/Z</b> is also
389 present, this data is replaced by spaces. This is a special feature for use in
390 the automatic test scripts; it ensures that the same output is generated for
391 different internal link sizes.
392 </P>
393 <P>
394 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
395 <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
396 </P>
397 <P>
398 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
399 2-byte and 4-byte fields in the compiled pattern. This facility is for testing
400 the feature in PCRE that allows it to execute patterns that were compiled on a
401 host with a different endianness. This feature is not available when the POSIX
402 interface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
403 specified. See also the section about saving and reloading compiled patterns
404 below.
405 </P>
406 <P>
407 The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
408 compiled pattern (whether it is anchored, has a fixed first character, and
409 so on). It does this by calling <b>pcre[16]_fullinfo()</b> after compiling a
410 pattern. If the pattern is studied, the results of that are also output.
411 </P>
412 <P>
413 The <b>/K</b> modifier requests <b>pcretest</b> to show names from backtracking
414 control verbs that are returned from calls to <b>pcre[16]_exec()</b>. It causes
415 <b>pcretest</b> to create a <b>pcre[16]_extra</b> block if one has not already
416 been created by a call to <b>pcre[16]_study()</b>, and to set the
417 PCRE_EXTRA_MARK flag and the <b>mark</b> field within it, every time that
418 <b>pcre[16]_exec()</b> is called. If the variable that the <b>mark</b> field
419 points to is non-NULL for a match, non-match, or partial match, <b>pcretest</b>
420 prints the string to which it points. For a match, this is shown on a line by
421 itself, tagged with "MK:". For a non-match it is added to the message.
422 </P>
423 <P>
424 The <b>/L</b> modifier must be followed directly by the name of a locale, for
425 example,
426 <pre>
427 /pattern/Lfr_FR
428 </pre>
429 For this reason, it must be the last modifier. The given locale is set,
430 <b>pcre[16]_maketables()</b> is called to build a set of character tables for
431 the locale, and this is then passed to <b>pcre[16]_compile()</b> when compiling
432 the regular expression. Without an <b>/L</b> (or <b>/T</b>) modifier, NULL is
433 passed as the tables pointer; that is, <b>/L</b> applies only to the expression
434 on which it appears.
435 </P>
436 <P>
437 The <b>/M</b> modifier causes the size in bytes of the memory block used to hold
438 the compiled pattern to be output. This does not include the size of the
439 <b>pcre[16]</b> block; it is just the actual compiled data. If the pattern is
440 successfully studied with the PCRE_STUDY_JIT_COMPILE option, the size of the
441 JIT compiled code is also output.
442 </P>
443 <P>
444 If the <b>/S</b> modifier appears once, it causes <b>pcre[16]_study()</b> to be
445 called after the expression has been compiled, and the results used when the
446 expression is matched. If <b>/S</b> appears twice, it suppresses studying, even
447 if it was requested externally by the <b>-s</b> command line option. This makes
448 it possible to specify that certain patterns are always studied, and others are
449 never studied, independently of <b>-s</b>. This feature is used in the test
450 files in a few cases where the output is different when the pattern is studied.
451 </P>
452 <P>
453 If the <b>/S</b> modifier is immediately followed by a + character, the call to
454 <b>pcre[16]_study()</b> is made with all the JIT study options, requesting
455 just-in-time optimization support if it is available, for both normal and
456 partial matching. If you want to restrict the JIT compiling modes, you can
457 follow <b>/S+</b> with a digit in the range 1 to 7:
458 <pre>
459 1 normal match only
460 2 soft partial match only
461 3 normal match and soft partial match
462 4 hard partial match only
463 6 soft and hard partial match
464 7 all three modes (default)
465 </pre>
466 If <b>/S++</b> is used instead of <b>/S+</b> (with or without a following digit),
467 the text "(JIT)" is added to the first output line after a match or no match
468 when JIT-compiled code was actually used.
469 </P>
470 <P>
471 Note that there is also an independent <b>/+</b> modifier; it must not be given
472 immediately after <b>/S</b> or <b>/S+</b> because this will be misinterpreted.
473 </P>
474 <P>
475 If JIT studying is successful, the compiled JIT code will automatically be used
476 when <b>pcre[16]_exec()</b> is run, except when incompatible run-time options
477 are specified. For more details, see the
478 <a href="pcrejit.html"><b>pcrejit</b></a>
479 documentation. See also the <b>\J</b> escape sequence below for a way of
480 setting the size of the JIT stack.
481 </P>
482 <P>
483 The <b>/T</b> modifier must be followed by a single digit. It causes a specific
484 set of built-in character tables to be passed to <b>pcre[16]_compile()</b>. It
485 is used in the standard PCRE tests to check behaviour with different character
486 tables. The digit specifies the tables as follows:
487 <pre>
488 0 the default ASCII tables, as distributed in
489 pcre_chartables.c.dist
490 1 a set of tables defining ISO 8859 characters
491 </pre>
492 In table 1, some characters whose codes are greater than 128 are identified as
493 letters, digits, spaces, etc.
494 </P>
495 <br><b>
496 Using the POSIX wrapper API
497 </b><br>
498 <P>
499 The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
500 API rather than its native API. This supports only the 8-bit library. When
501 <b>/P</b> is set, the following modifiers set options for the <b>regcomp()</b>
502 function:
503 <pre>
504 /i REG_ICASE
505 /m REG_NEWLINE
506 /N REG_NOSUB
507 /s REG_DOTALL )
508 /U REG_UNGREEDY ) These options are not part of
509 /W REG_UCP ) the POSIX standard
510 /8 REG_UTF8 )
511 </pre>
512 The <b>/+</b> modifier works as described above. All other modifiers are
513 ignored.
514 </P>
515 <br><a name="SEC6" href="#TOC1">DATA LINES</a><br>
516 <P>
517 Before each data line is passed to <b>pcre[16]_exec()</b>, leading and trailing
518 white space is removed, and it is then scanned for \ escapes. Some of these
519 are pretty esoteric features, intended for checking out some of the more
520 complicated features of PCRE. If you are just testing "ordinary" regular
521 expressions, you probably don't need any of these. The following escapes are
522 recognized:
523 <pre>
524 \a alarm (BEL, \x07)
525 \b backspace (\x08)
526 \e escape (\x27)
527 \f form feed (\x0c)
528 \n newline (\x0a)
529 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
530 \r carriage return (\x0d)
531 \t tab (\x09)
532 \v vertical tab (\x0b)
533 \nnn octal character (up to 3 octal digits); always
534 a byte unless &#62; 255 in UTF-8 or 16-bit mode
535 \xhh hexadecimal byte (up to 2 hex digits)
536 \x{hh...} hexadecimal character (any number of hex digits)
537 \A pass the PCRE_ANCHORED option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
538 \B pass the PCRE_NOTBOL option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
539 \Cdd call pcre[16]_copy_substring() for substring dd after a successful match (number less than 32)
540 \Cname call pcre[16]_copy_named_substring() for substring "name" after a successful match (name termin-
541 ated by next non alphanumeric character)
542 \C+ show the current captured substrings at callout time
543 \C- do not supply a callout function
544 \C!n return 1 instead of 0 when callout number n is reached
545 \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
546 \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
547 \D use the <b>pcre[16]_dfa_exec()</b> match function
548 \F only shortest match for <b>pcre[16]_dfa_exec()</b>
549 \Gdd call pcre[16]_get_substring() for substring dd after a successful match (number less than 32)
550 \Gname call pcre[16]_get_named_substring() for substring "name" after a successful match (name termin-
551 ated by next non-alphanumeric character)
552 \Jdd set up a JIT stack of dd kilobytes maximum (any number of digits)
553 \L call pcre[16]_get_substringlist() after a successful match
554 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
555 \N pass the PCRE_NOTEMPTY option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>; if used twice, pass the
556 PCRE_NOTEMPTY_ATSTART option
557 \Odd set the size of the output vector passed to <b>pcre[16]_exec()</b> to dd (any number of digits)
558 \P pass the PCRE_PARTIAL_SOFT option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>; if used twice, pass the
559 PCRE_PARTIAL_HARD option
560 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
561 \R pass the PCRE_DFA_RESTART option to <b>pcre[16]_dfa_exec()</b>
562 \S output details of memory get/free calls during matching
563 \Y pass the PCRE_NO_START_OPTIMIZE option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
564 \Z pass the PCRE_NOTEOL option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
565 \? pass the PCRE_NO_UTF[8|16]_CHECK option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
566 \&#62;dd start the match at offset dd (optional "-"; then any number of digits); this sets the <i>startoffset</i>
567 argument for <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
568 \&#60;cr&#62; pass the PCRE_NEWLINE_CR option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
569 \&#60;lf&#62; pass the PCRE_NEWLINE_LF option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
570 \&#60;crlf&#62; pass the PCRE_NEWLINE_CRLF option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
571 \&#60;anycrlf&#62; pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
572 \&#60;any&#62; pass the PCRE_NEWLINE_ANY option to <b>pcre[16]_exec()</b> or <b>pcre[16]_dfa_exec()</b>
573 </pre>
574 The use of \x{hh...} is not dependent on the use of the <b>/8</b> modifier on
575 the pattern. It is recognized always. There may be any number of hexadecimal
576 digits inside the braces; invalid values provoke error messages.
577 </P>
578 <P>
579 Note that \xhh specifies one byte rather than one character in UTF-8 mode;
580 this makes it possible to construct invalid UTF-8 sequences for testing
581 purposes. On the other hand, \x{hh} is interpreted as a UTF-8 character in
582 UTF-8 mode, generating more than one byte if the value is greater than 127.
583 When testing the 8-bit library not in UTF-8 mode, \x{hh} generates one byte
584 for values less than 256, and causes an error for greater values.
585 </P>
586 <P>
587 In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
588 possible to construct invalid UTF-16 sequences for testing purposes.
589 </P>
590 <P>
591 The escapes that specify line ending sequences are literal strings, exactly as
592 shown. No more than one newline setting should be present in any data line.
593 </P>
594 <P>
595 A backslash followed by anything else just escapes the anything else. If
596 the very last character is a backslash, it is ignored. This gives a way of
597 passing an empty line as data, since a real empty line terminates the data
598 input.
599 </P>
600 <P>
601 The <b>\J</b> escape provides a way of setting the maximum stack size that is
602 used by the just-in-time optimization code. It is ignored if JIT optimization
603 is not being used. Providing a stack that is larger than the default 32K is
604 necessary only for very complicated patterns.
605 </P>
606 <P>
607 If \M is present, <b>pcretest</b> calls <b>pcre[16]_exec()</b> several times,
608 with different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
609 fields of the <b>pcre[16]_extra</b> data structure, until it finds the minimum
610 numbers for each parameter that allow <b>pcre[16]_exec()</b> to complete without
611 error. Because this is testing a specific feature of the normal interpretive
612 <b>pcre[16]_exec()</b> execution, the use of any JIT optimization that might
613 have been set up by the <b>/S+</b> qualifier of <b>-s+</b> option is disabled.
614 </P>
615 <P>
616 The <i>match_limit</i> number is a measure of the amount of backtracking
617 that takes place, and checking it out can be instructive. For most simple
618 matches, the number is quite small, but for patterns with very large numbers of
619 matching possibilities, it can become large very quickly with increasing length
620 of subject string. The <i>match_limit_recursion</i> number is a measure of how
621 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is
622 needed to complete the match attempt.
623 </P>
624 <P>
625 When \O is used, the value specified may be higher or lower than the size set
626 by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
627 the call of <b>pcre[16]_exec()</b> for the line in which it appears.
628 </P>
629 <P>
630 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
631 API to be used, the only option-setting sequences that have any effect are \B,
632 \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,
633 to be passed to <b>regexec()</b>.
634 </P>
635 <br><a name="SEC7" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
636 <P>
637 By default, <b>pcretest</b> uses the standard PCRE matching function,
638 <b>pcre[16]_exec()</b> to match each data line. PCRE also supports an
639 alternative matching function, <b>pcre[16]_dfa_test()</b>, which operates in a
640 different way, and has some restrictions. The differences between the two
641 functions are described in the
642 <a href="pcrematching.html"><b>pcrematching</b></a>
643 documentation.
644 </P>
645 <P>
646 If a data line contains the \D escape sequence, or if the command line
647 contains the <b>-dfa</b> option, the alternative matching function is used.
648 This function finds all possible matches at a given point. If, however, the \F
649 escape sequence is present in the data line, it stops after the first match is
650 found. This is always the shortest possible match.
651 </P>
652 <br><a name="SEC8" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
653 <P>
654 This section describes the output when the normal matching function,
655 <b>pcre[16]_exec()</b>, is being used.
656 </P>
657 <P>
658 When a match succeeds, <b>pcretest</b> outputs the list of captured substrings
659 that <b>pcre[16]_exec()</b> returns, starting with number 0 for the string that
660 matched the whole pattern. Otherwise, it outputs "No match" when the return is
661 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
662 substring when <b>pcre[16]_exec()</b> returns PCRE_ERROR_PARTIAL. (Note that
663 this is the entire substring that was inspected during the partial match; it
664 may include characters before the actual match start if a lookbehind assertion,
665 \K, \b, or \B was involved.) For any other return, <b>pcretest</b> outputs
666 the PCRE negative error number and a short descriptive phrase. If the error is
667 a failed UTF string check, the offset of the start of the failing character and
668 the reason code are also output, provided that the size of the output vector is
669 at least two. Here is an example of an interactive <b>pcretest</b> run.
670 <pre>
671 $ pcretest
672 PCRE version 8.13 2011-04-30
673
674 re&#62; /^abc(\d+)/
675 data&#62; abc123
676 0: abc123
677 1: 123
678 data&#62; xyz
679 No match
680 </pre>
681 Unset capturing substrings that are not followed by one that is set are not
682 returned by <b>pcre[16]_exec()</b>, and are not shown by <b>pcretest</b>. In the
683 following example, there are two capturing substrings, but when the first data
684 line is matched, the second, unset substring is not shown. An "internal" unset
685 substring is shown as "&#60;unset&#62;", as for the second data line.
686 <pre>
687 re&#62; /(a)|(b)/
688 data&#62; a
689 0: a
690 1: a
691 data&#62; b
692 0: b
693 1: &#60;unset&#62;
694 2: b
695 </pre>
696 If the strings contain any non-printing characters, they are output as \xhh
697 escapes if the value is less than 256 and UTF mode is not set. Otherwise they
698 are output as \x{hh...} escapes. See below for the definition of non-printing
699 characters. If the pattern has the <b>/+</b> modifier, the output for substring
700 0 is followed by the the rest of the subject string, identified by "0+" like
701 this:
702 <pre>
703 re&#62; /cat/+
704 data&#62; cataract
705 0: cat
706 0+ aract
707 </pre>
708 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
709 matching attempts are output in sequence, like this:
710 <pre>
711 re&#62; /\Bi(\w\w)/g
712 data&#62; Mississippi
713 0: iss
714 1: ss
715 0: iss
716 1: ss
717 0: ipp
718 1: pp
719 </pre>
720 "No match" is output only if the first match attempt fails. Here is an example
721 of a failure message (the offset 4 that is specified by \&#62;4 is past the end of
722 the subject string):
723 <pre>
724 re&#62; /xyz/
725 data&#62; xyz\&#62;4
726 Error -24 (bad offset value)
727 </PRE>
728 </P>
729 <P>
730 If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
731 data line that is successfully matched, the substrings extracted by the
732 convenience functions are output with C, G, or L after the string number
733 instead of a colon. This is in addition to the normal full list. The string
734 length (that is, the return from the extraction function) is given in
735 parentheses after each string for <b>\C</b> and <b>\G</b>.
736 </P>
737 <P>
738 Note that whereas patterns can be continued over several lines (a plain "&#62;"
739 prompt is used for continuations), data lines may not. However newlines can be
740 included in data by means of the \n escape (or \r, \r\n, etc., depending on
741 the newline sequence setting).
742 </P>
743 <br><a name="SEC9" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
744 <P>
745 When the alternative matching function, <b>pcre[16]_dfa_exec()</b>, is used (by
746 means of the \D escape sequence or the <b>-dfa</b> command line option), the
747 output consists of a list of all the matches that start at the first point in
748 the subject where there is at least one match. For example:
749 <pre>
750 re&#62; /(tang|tangerine|tan)/
751 data&#62; yellow tangerine\D
752 0: tangerine
753 1: tang
754 2: tan
755 </pre>
756 (Using the normal matching function on this data finds only "tang".) The
757 longest matching string is always given first (and numbered zero). After a
758 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
759 partially matching substring. (Note that this is the entire substring that was
760 inspected during the partial match; it may include characters before the actual
761 match start if a lookbehind assertion, \K, \b, or \B was involved.)
762 </P>
763 <P>
764 If <b>/g</b> is present on the pattern, the search for further matches resumes
765 at the end of the longest match. For example:
766 <pre>
767 re&#62; /(tang|tangerine|tan)/g
768 data&#62; yellow tangerine and tangy sultana\D
769 0: tangerine
770 1: tang
771 2: tan
772 0: tang
773 1: tan
774 0: tan
775 </pre>
776 Since the matching function does not support substring capture, the escape
777 sequences that are concerned with captured substrings are not relevant.
778 </P>
779 <br><a name="SEC10" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
780 <P>
781 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
782 indicating that the subject partially matched the pattern, you can restart the
783 match with additional subject data by means of the \R escape sequence. For
784 example:
785 <pre>
786 re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
787 data&#62; 23ja\P\D
788 Partial match: 23ja
789 data&#62; n05\R\D
790 0: n05
791 </pre>
792 For further information about partial matching, see the
793 <a href="pcrepartial.html"><b>pcrepartial</b></a>
794 documentation.
795 </P>
796 <br><a name="SEC11" href="#TOC1">CALLOUTS</a><br>
797 <P>
798 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
799 is called during matching. This works with both matching functions. By default,
800 the called function displays the callout number, the start and current
801 positions in the text at the callout time, and the next pattern item to be
802 tested. For example:
803 <pre>
804 ---&#62;pqrabcdef
805 0 ^ ^ \d
806 </pre>
807 This output indicates that callout number 0 occurred for a match attempt
808 starting at the fourth character of the subject string, when the pointer was at
809 the seventh character of the data, and when the next pattern item was \d. Just
810 one circumflex is output if the start and current positions are the same.
811 </P>
812 <P>
813 Callouts numbered 255 are assumed to be automatic callouts, inserted as a
814 result of the <b>/C</b> pattern modifier. In this case, instead of showing the
815 callout number, the offset in the pattern, preceded by a plus, is output. For
816 example:
817 <pre>
818 re&#62; /\d?[A-E]\*/C
819 data&#62; E*
820 ---&#62;E*
821 +0 ^ \d?
822 +3 ^ [A-E]
823 +8 ^^ \*
824 +10 ^ ^
825 0: E*
826 </pre>
827 If a pattern contains (*MARK) items, an additional line is output whenever
828 a change of latest mark is passed to the callout function. For example:
829 <pre>
830 re&#62; /a(*MARK:X)bc/C
831 data&#62; abc
832 ---&#62;abc
833 +0 ^ a
834 +1 ^^ (*MARK:X)
835 +10 ^^ b
836 Latest Mark: X
837 +11 ^ ^ c
838 +12 ^ ^
839 0: abc
840 </pre>
841 The mark changes between matching "a" and "b", but stays the same for the rest
842 of the match, so nothing more is output. If, as a result of backtracking, the
843 mark reverts to being unset, the text "&#60;unset&#62;" is output.
844 </P>
845 <P>
846 The callout function in <b>pcretest</b> returns zero (carry on matching) by
847 default, but you can use a \C item in a data line (as described above) to
848 change this and other parameters of the callout.
849 </P>
850 <P>
851 Inserting callouts can be helpful when using <b>pcretest</b> to check
852 complicated regular expressions. For further information about callouts, see
853 the
854 <a href="pcrecallout.html"><b>pcrecallout</b></a>
855 documentation.
856 </P>
857 <br><a name="SEC12" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
858 <P>
859 When <b>pcretest</b> is outputting text in the compiled version of a pattern,
860 bytes other than 32-126 are always treated as non-printing characters are are
861 therefore shown as hex escapes.
862 </P>
863 <P>
864 When <b>pcretest</b> is outputting text that is a matched part of a subject
865 string, it behaves in the same way, unless a different locale has been set for
866 the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
867 function to distinguish printing and non-printing characters.
868 </P>
869 <br><a name="SEC13" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
870 <P>
871 The facilities described in this section are not available when the POSIX
872 interface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
873 specified.
874 </P>
875 <P>
876 When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
877 compiled pattern to a file, by following the modifiers with &#62; and a file name.
878 For example:
879 <pre>
880 /pattern/im &#62;/some/file
881 </pre>
882 See the
883 <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
884 documentation for a discussion about saving and re-using compiled patterns.
885 Note that if the pattern was successfully studied with JIT optimization, the
886 JIT data cannot be saved.
887 </P>
888 <P>
889 The data that is written is binary. The first eight bytes are the length of the
890 compiled pattern data followed by the length of the optional study data, each
891 written as four bytes in big-endian order (most significant byte first). If
892 there is no study data (either the pattern was not studied, or studying did not
893 return any data), the second length is zero. The lengths are followed by an
894 exact copy of the compiled pattern. If there is additional study data, this
895 (excluding any JIT data) follows immediately after the compiled pattern. After
896 writing the file, <b>pcretest</b> expects to read a new pattern.
897 </P>
898 <P>
899 A saved pattern can be reloaded into <b>pcretest</b> by specifying &#60; and a file
900 name instead of a pattern. The name of the file must not contain a &#60; character,
901 as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by &#60;
902 characters.
903 For example:
904 <pre>
905 re&#62; &#60;/some/file
906 Compiled pattern loaded from /some/file
907 No study data
908 </pre>
909 If the pattern was previously studied with the JIT optimization, the JIT
910 information cannot be saved and restored, and so is lost. When the pattern has
911 been loaded, <b>pcretest</b> proceeds to read data lines in the usual way.
912 </P>
913 <P>
914 You can copy a file written by <b>pcretest</b> to a different host and reload it
915 there, even if the new host has opposite endianness to the one on which the
916 pattern was compiled. For example, you can compile on an i86 machine and run on
917 a SPARC machine. When a pattern is reloaded on a host with different
918 endianness, the confirmation message is changed to:
919 <pre>
920 Compiled pattern (byte-inverted) loaded from /some/file
921 </pre>
922 The test suite contains some saved pre-compiled patterns with different
923 endianness. These are reloaded using "&#60;!" instead of just "&#60;". This suppresses
924 the "(byte-inverted)" text so that the output is the same on all hosts. It also
925 forces debugging output once the pattern has been reloaded.
926 </P>
927 <P>
928 File names for saving and reloading can be absolute or relative, but note that
929 the shell facility of expanding a file name that starts with a tilde (~) is not
930 available.
931 </P>
932 <P>
933 The ability to save and reload files in <b>pcretest</b> is intended for testing
934 and experimentation. It is not intended for production use because only a
935 single pattern can be written to a file. Furthermore, there is no facility for
936 supplying custom character tables for use with a reloaded pattern. If the
937 original pattern was compiled with custom tables, an attempt to match a subject
938 string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
939 Finally, if you attempt to load a file that is not in the correct format, the
940 result is undefined.
941 </P>
942 <br><a name="SEC14" href="#TOC1">SEE ALSO</a><br>
943 <P>
944 <b>pcre</b>(3), <b>pcre16</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3),
945 <b>pcrejit</b>, <b>pcrematching</b>(3), <b>pcrepartial</b>(d),
946 <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3).
947 </P>
948 <br><a name="SEC15" href="#TOC1">AUTHOR</a><br>
949 <P>
950 Philip Hazel
951 <br>
952 University Computing Service
953 <br>
954 Cambridge CB2 3QH, England.
955 <br>
956 </P>
957 <br><a name="SEC16" href="#TOC1">REVISION</a><br>
958 <P>
959 Last updated: 21 February 2012
960 <br>
961 Copyright &copy; 1997-2012 University of Cambridge.
962 <br>
963 <p>
964 Return to the <a href="index.html">PCRE index page</a>.
965 </p>

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