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1 PCRETEST(1) General Commands Manual PCRETEST(1)
2
3
4
5 NAME
6 pcretest - a program for testing Perl-compatible regular expressions.
7
8 SYNOPSIS
9
10 pcretest [options] [input file [output file]]
11
12 pcretest was written as a test program for the PCRE regular expression
13 library itself, but it can also be used for experimenting with regular
14 expressions. This document describes the features of the test program;
15 for details of the regular expressions themselves, see the pcrepattern
16 documentation. For details of the PCRE library function calls and their
17 options, see the pcreapi , pcre16 and pcre32 documentation.
18
19 The input for pcretest is a sequence of regular expression patterns and
20 strings to be matched, as described below. The output shows the result
21 of each match. Options on the command line and the patterns control
22 PCRE options and exactly what is output.
23
24 As PCRE has evolved, it has acquired many different features, and as a
25 result, pcretest now has rather a lot of obscure options for testing
26 every possible feature. Some of these options are specifically designed
27 for use in conjunction with the test script and data files that are
28 distributed as part of PCRE, and are unlikely to be of use otherwise.
29 They are all documented here, but without much justification.
30
31
32 INPUT DATA FORMAT
33
34 Input to pcretest is processed line by line, either by calling the C
35 library's fgets() function, or via the libreadline library (see below).
36 In Unix-like environments, fgets() treats any bytes other than newline
37 as data characters. However, in some Windows environments character 26
38 (hex 1A) causes an immediate end of file, and no further data is read.
39 For maximum portability, therefore, it is safest to use only ASCII
40 characters in pcretest input files.
41
42
43 PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES
44
45 From release 8.30, two separate PCRE libraries can be built. The origi-
46 nal one supports 8-bit character strings, whereas the newer 16-bit
47 library supports character strings encoded in 16-bit units. From
48 release 8.32, a third library can be built, supporting character
49 strings encoded in 32-bit units. The pcretest program can be used to
50 test all three libraries. However, it is itself still an 8-bit program,
51 reading 8-bit input and writing 8-bit output. When testing the 16-bit
52 or 32-bit library, the patterns and data strings are converted to 16-
53 or 32-bit format before being passed to the PCRE library functions.
54 Results are converted to 8-bit for output.
55
56 References to functions and structures of the form pcre[16|32]_xx below
57 mean "pcre_xx when using the 8-bit library, pcre16_xx when using the
58 16-bit library, or pcre32_xx when using the 32-bit library".
59
60
61 COMMAND LINE OPTIONS
62
63 -8 If both the 8-bit library has been built, this option causes
64 the 8-bit library to be used (which is the default); if the
65 8-bit library has not been built, this option causes an
66 error.
67
68 -16 If both the 8-bit or the 32-bit, and the 16-bit libraries
69 have been built, this option causes the 16-bit library to be
70 used. If only the 16-bit library has been built, this is the
71 default (so has no effect). If only the 8-bit or the 32-bit
72 library has been built, this option causes an error.
73
74 -32 If both the 8-bit or the 16-bit, and the 32-bit libraries
75 have been built, this option causes the 32-bit library to be
76 used. If only the 32-bit library has been built, this is the
77 default (so has no effect). If only the 8-bit or the 16-bit
78 library has been built, this option causes an error.
79
80 -b Behave as if each pattern has the /B (show byte code) modi-
81 fier; the internal form is output after compilation.
82
83 -C Output the version number of the PCRE library, and all avail-
84 able information about the optional features that are
85 included, and then exit with zero exit code. All other
86 options are ignored.
87
88 -C option Output information about a specific build-time option, then
89 exit. This functionality is intended for use in scripts such
90 as RunTest. The following options output the value and set
91 the exit code as indicated:
92
93 ebcdic-nl the code for LF (= NL) in an EBCDIC environment:
94 0x15 or 0x25
95 0 if used in an ASCII environment
96 exit code is always 0
97 linksize the configured internal link size (2, 3, or 4)
98 exit code is set to the link size
99 newline the default newline setting:
100 CR, LF, CRLF, ANYCRLF, or ANY
101 exit code is always 0
102
103 The following options output 1 for true or 0 for false, and
104 set the exit code to the same value:
105
106 ebcdic compiled for an EBCDIC environment
107 jit just-in-time support is available
108 pcre16 the 16-bit library was built
109 pcre32 the 32-bit library was built
110 pcre8 the 8-bit library was built
111 ucp Unicode property support is available
112 utf UTF-8 and/or UTF-16 and/or UTF-32 support
113 is available
114
115 If an unknown option is given, an error message is output;
116 the exit code is 0.
117
118 -d Behave as if each pattern has the /D (debug) modifier; the
119 internal form and information about the compiled pattern is
120 output after compilation; -d is equivalent to -b -i.
121
122 -dfa Behave as if each data line contains the \D escape sequence;
123 this causes the alternative matching function,
124 pcre[16|32]_dfa_exec(), to be used instead of the standard
125 pcre[16|32]_exec() function (more detail is given below).
126
127 -help Output a brief summary these options and then exit.
128
129 -i Behave as if each pattern has the /I modifier; information
130 about the compiled pattern is given after compilation.
131
132 -M Behave as if each data line contains the \M escape sequence;
133 this causes PCRE to discover the minimum MATCH_LIMIT and
134 MATCH_LIMIT_RECURSION settings by calling pcre[16|32]_exec()
135 repeatedly with different limits.
136
137 -m Output the size of each compiled pattern after it has been
138 compiled. This is equivalent to adding /M to each regular
139 expression. The size is given in bytes for both libraries.
140
141 -o osize Set the number of elements in the output vector that is used
142 when calling pcre[16|32]_exec() or pcre[16|32]_dfa_exec() to
143 be osize. The default value is 45, which is enough for 14
144 capturing subexpressions for pcre[16|32]_exec() or 22 differ-
145 ent matches for pcre[16|32]_dfa_exec(). The vector size can
146 be changed for individual matching calls by including \O in
147 the data line (see below).
148
149 -p Behave as if each pattern has the /P modifier; the POSIX
150 wrapper API is used to call PCRE. None of the other options
151 has any effect when -p is set. This option can be used only
152 with the 8-bit library.
153
154 -q Do not output the version number of pcretest at the start of
155 execution.
156
157 -S size On Unix-like systems, set the size of the run-time stack to
158 size megabytes.
159
160 -s or -s+ Behave as if each pattern has the /S modifier; in other
161 words, force each pattern to be studied. If -s+ is used, all
162 the JIT compile options are passed to pcre[16|32]_study(),
163 causing just-in-time optimization to be set up if it is
164 available, for both full and partial matching. Specific JIT
165 compile options can be selected by following -s+ with a digit
166 in the range 1 to 7, which selects the JIT compile modes as
167 follows:
168
169 1 normal match only
170 2 soft partial match only
171 3 normal match and soft partial match
172 4 hard partial match only
173 6 soft and hard partial match
174 7 all three modes (default)
175
176 If -s++ is used instead of -s+ (with or without a following
177 digit), the text "(JIT)" is added to the first output line
178 after a match or no match when JIT-compiled code was actually
179 used.
180
181 Note that there are pattern options that can override -s,
182 either specifying no studying at all, or suppressing JIT com-
183 pilation.
184
185 If the /I or /D option is present on a pattern (requesting
186 output about the compiled pattern), information about the
187 result of studying is not included when studying is caused
188 only by -s and neither -i nor -d is present on the command
189 line. This behaviour means that the output from tests that
190 are run with and without -s should be identical, except when
191 options that output information about the actual running of a
192 match are set.
193
194 The -M, -t, and -tm options, which give information about
195 resources used, are likely to produce different output with
196 and without -s. Output may also differ if the /C option is
197 present on an individual pattern. This uses callouts to trace
198 the the matching process, and this may be different between
199 studied and non-studied patterns. If the pattern contains
200 (*MARK) items there may also be differences, for the same
201 reason. The -s command line option can be overridden for spe-
202 cific patterns that should never be studied (see the /S pat-
203 tern modifier below).
204
205 -t Run each compile, study, and match many times with a timer,
206 and output resulting time per compile or match (in millisec-
207 onds). Do not set -m with -t, because you will then get the
208 size output a zillion times, and the timing will be dis-
209 torted. You can control the number of iterations that are
210 used for timing by following -t with a number (as a separate
211 item on the command line). For example, "-t 1000" would iter-
212 ate 1000 times. The default is to iterate 500000 times.
213
214 -tm This is like -t except that it times only the matching phase,
215 not the compile or study phases.
216
217
218 DESCRIPTION
219
220 If pcretest is given two filename arguments, it reads from the first
221 and writes to the second. If it is given only one filename argument, it
222 reads from that file and writes to stdout. Otherwise, it reads from
223 stdin and writes to stdout, and prompts for each line of input, using
224 "re>" to prompt for regular expressions, and "data>" to prompt for data
225 lines.
226
227 When pcretest is built, a configuration option can specify that it
228 should be linked with the libreadline library. When this is done, if
229 the input is from a terminal, it is read using the readline() function.
230 This provides line-editing and history facilities. The output from the
231 -help option states whether or not readline() will be used.
232
233 The program handles any number of sets of input on a single input file.
234 Each set starts with a regular expression, and continues with any num-
235 ber of data lines to be matched against the pattern.
236
237 Each data line is matched separately and independently. If you want to
238 do multi-line matches, you have to use the \n escape sequence (or \r or
239 \r\n, etc., depending on the newline setting) in a single line of input
240 to encode the newline sequences. There is no limit on the length of
241 data lines; the input buffer is automatically extended if it is too
242 small.
243
244 An empty line signals the end of the data lines, at which point a new
245 regular expression is read. The regular expressions are given enclosed
246 in any non-alphanumeric delimiters other than backslash, for example:
247
248 /(a|bc)x+yz/
249
250 White space before the initial delimiter is ignored. A regular expres-
251 sion may be continued over several input lines, in which case the new-
252 line characters are included within it. It is possible to include the
253 delimiter within the pattern by escaping it, for example
254
255 /abc\/def/
256
257 If you do so, the escape and the delimiter form part of the pattern,
258 but since delimiters are always non-alphanumeric, this does not affect
259 its interpretation. If the terminating delimiter is immediately fol-
260 lowed by a backslash, for example,
261
262 /abc/\
263
264 then a backslash is added to the end of the pattern. This is done to
265 provide a way of testing the error condition that arises if a pattern
266 finishes with a backslash, because
267
268 /abc\/
269
270 is interpreted as the first line of a pattern that starts with "abc/",
271 causing pcretest to read the next line as a continuation of the regular
272 expression.
273
274
275 PATTERN MODIFIERS
276
277 A pattern may be followed by any number of modifiers, which are mostly
278 single characters, though some of these can be qualified by further
279 characters. Following Perl usage, these are referred to below as, for
280 example, "the /i modifier", even though the delimiter of the pattern
281 need not always be a slash, and no slash is used when writing modi-
282 fiers. White space may appear between the final pattern delimiter and
283 the first modifier, and between the modifiers themselves. For refer-
284 ence, here is a complete list of modifiers. They fall into several
285 groups that are described in detail in the following sections.
286
287 /8 set UTF mode
288 /9 set PCRE_NEVER_UTF (locks out UTF mode)
289 /? disable UTF validity check
290 /+ show remainder of subject after match
291 /= show all captures (not just those that are set)
292
293 /A set PCRE_ANCHORED
294 /B show compiled code
295 /C set PCRE_AUTO_CALLOUT
296 /D same as /B plus /I
297 /E set PCRE_DOLLAR_ENDONLY
298 /F flip byte order in compiled pattern
299 /f set PCRE_FIRSTLINE
300 /G find all matches (shorten string)
301 /g find all matches (use startoffset)
302 /I show information about pattern
303 /i set PCRE_CASELESS
304 /J set PCRE_DUPNAMES
305 /K show backtracking control names
306 /L set locale
307 /M show compiled memory size
308 /m set PCRE_MULTILINE
309 /N set PCRE_NO_AUTO_CAPTURE
310 /P use the POSIX wrapper
311 /S study the pattern after compilation
312 /s set PCRE_DOTALL
313 /T select character tables
314 /U set PCRE_UNGREEDY
315 /W set PCRE_UCP
316 /X set PCRE_EXTRA
317 /x set PCRE_EXTENDED
318 /Y set PCRE_NO_START_OPTIMIZE
319 /Z don't show lengths in /B output
320
321 /<any> set PCRE_NEWLINE_ANY
322 /<anycrlf> set PCRE_NEWLINE_ANYCRLF
323 /<cr> set PCRE_NEWLINE_CR
324 /<crlf> set PCRE_NEWLINE_CRLF
325 /<lf> set PCRE_NEWLINE_LF
326 /<bsr_anycrlf> set PCRE_BSR_ANYCRLF
327 /<bsr_unicode> set PCRE_BSR_UNICODE
328 /<JS> set PCRE_JAVASCRIPT_COMPAT
329
330
331 Perl-compatible modifiers
332
333 The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
334 PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
335 pcre[16|32]_compile() is called. These four modifier letters have the
336 same effect as they do in Perl. For example:
337
338 /caseless/i
339
340
341 Modifiers for other PCRE options
342
343 The following table shows additional modifiers for setting PCRE com-
344 pile-time options that do not correspond to anything in Perl:
345
346 /8 PCRE_UTF8 ) when using the 8-bit
347 /? PCRE_NO_UTF8_CHECK ) library
348
349 /8 PCRE_UTF16 ) when using the 16-bit
350 /? PCRE_NO_UTF16_CHECK ) library
351
352 /8 PCRE_UTF32 ) when using the 32-bit
353 /? PCRE_NO_UTF32_CHECK ) library
354
355 /9 PCRE_NEVER_UTF
356 /A PCRE_ANCHORED
357 /C PCRE_AUTO_CALLOUT
358 /E PCRE_DOLLAR_ENDONLY
359 /f PCRE_FIRSTLINE
360 /J PCRE_DUPNAMES
361 /N PCRE_NO_AUTO_CAPTURE
362 /U PCRE_UNGREEDY
363 /W PCRE_UCP
364 /X PCRE_EXTRA
365 /Y PCRE_NO_START_OPTIMIZE
366 /<any> PCRE_NEWLINE_ANY
367 /<anycrlf> PCRE_NEWLINE_ANYCRLF
368 /<cr> PCRE_NEWLINE_CR
369 /<crlf> PCRE_NEWLINE_CRLF
370 /<lf> PCRE_NEWLINE_LF
371 /<bsr_anycrlf> PCRE_BSR_ANYCRLF
372 /<bsr_unicode> PCRE_BSR_UNICODE
373 /<JS> PCRE_JAVASCRIPT_COMPAT
374
375 The modifiers that are enclosed in angle brackets are literal strings
376 as shown, including the angle brackets, but the letters within can be
377 in either case. This example sets multiline matching with CRLF as the
378 line ending sequence:
379
380 /^abc/m<CRLF>
381
382 As well as turning on the PCRE_UTF8/16/32 option, the /8 modifier
383 causes all non-printing characters in output strings to be printed
384 using the \x{hh...} notation. Otherwise, those less than 0x100 are out-
385 put in hex without the curly brackets.
386
387 Full details of the PCRE options are given in the pcreapi documenta-
388 tion.
389
390 Finding all matches in a string
391
392 Searching for all possible matches within each subject string can be
393 requested by the /g or /G modifier. After finding a match, PCRE is
394 called again to search the remainder of the subject string. The differ-
395 ence between /g and /G is that the former uses the startoffset argument
396 to pcre[16|32]_exec() to start searching at a new point within the
397 entire string (which is in effect what Perl does), whereas the latter
398 passes over a shortened substring. This makes a difference to the
399 matching process if the pattern begins with a lookbehind assertion
400 (including \b or \B).
401
402 If any call to pcre[16|32]_exec() in a /g or /G sequence matches an
403 empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
404 PCRE_ANCHORED flags set in order to search for another, non-empty,
405 match at the same point. If this second match fails, the start offset
406 is advanced, and the normal match is retried. This imitates the way
407 Perl handles such cases when using the /g modifier or the split() func-
408 tion. Normally, the start offset is advanced by one character, but if
409 the newline convention recognizes CRLF as a newline, and the current
410 character is CR followed by LF, an advance of two is used.
411
412 Other modifiers
413
414 There are yet more modifiers for controlling the way pcretest operates.
415
416 The /+ modifier requests that as well as outputting the substring that
417 matched the entire pattern, pcretest should in addition output the
418 remainder of the subject string. This is useful for tests where the
419 subject contains multiple copies of the same substring. If the + modi-
420 fier appears twice, the same action is taken for captured substrings.
421 In each case the remainder is output on the following line with a plus
422 character following the capture number. Note that this modifier must
423 not immediately follow the /S modifier because /S+ and /S++ have other
424 meanings.
425
426 The /= modifier requests that the values of all potential captured
427 parentheses be output after a match. By default, only those up to the
428 highest one actually used in the match are output (corresponding to the
429 return code from pcre[16|32]_exec()). Values in the offsets vector cor-
430 responding to higher numbers should be set to -1, and these are output
431 as "<unset>". This modifier gives a way of checking that this is hap-
432 pening.
433
434 The /B modifier is a debugging feature. It requests that pcretest out-
435 put a representation of the compiled code after compilation. Normally
436 this information contains length and offset values; however, if /Z is
437 also present, this data is replaced by spaces. This is a special fea-
438 ture for use in the automatic test scripts; it ensures that the same
439 output is generated for different internal link sizes.
440
441 The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
442 that is, both the /B and the /I modifiers.
443
444 The /F modifier causes pcretest to flip the byte order of the 2-byte
445 and 4-byte fields in the compiled pattern. This facility is for testing
446 the feature in PCRE that allows it to execute patterns that were com-
447 piled on a host with a different endianness. This feature is not avail-
448 able when the POSIX interface to PCRE is being used, that is, when the
449 /P pattern modifier is specified. See also the section about saving and
450 reloading compiled patterns below.
451
452 The /I modifier requests that pcretest output information about the
453 compiled pattern (whether it is anchored, has a fixed first character,
454 and so on). It does this by calling pcre[16|32]_fullinfo() after com-
455 piling a pattern. If the pattern is studied, the results of that are
456 also output.
457
458 The /K modifier requests pcretest to show names from backtracking con-
459 trol verbs that are returned from calls to pcre[16|32]_exec(). It
460 causes pcretest to create a pcre[16|32]_extra block if one has not
461 already been created by a call to pcre[16|32]_study(), and to set the
462 PCRE_EXTRA_MARK flag and the mark field within it, every time that
463 pcre[16|32]_exec() is called. If the variable that the mark field
464 points to is non-NULL for a match, non-match, or partial match,
465 pcretest prints the string to which it points. For a match, this is
466 shown on a line by itself, tagged with "MK:". For a non-match it is
467 added to the message.
468
469 The /L modifier must be followed directly by the name of a locale, for
470 example,
471
472 /pattern/Lfr_FR
473
474 For this reason, it must be the last modifier. The given locale is set,
475 pcre[16|32]_maketables() is called to build a set of character tables
476 for the locale, and this is then passed to pcre[16|32]_compile() when
477 compiling the regular expression. Without an /L (or /T) modifier, NULL
478 is passed as the tables pointer; that is, /L applies only to the
479 expression on which it appears.
480
481 The /M modifier causes the size in bytes of the memory block used to
482 hold the compiled pattern to be output. This does not include the size
483 of the pcre[16|32] block; it is just the actual compiled data. If the
484 pattern is successfully studied with the PCRE_STUDY_JIT_COMPILE option,
485 the size of the JIT compiled code is also output.
486
487 The /S modifier causes pcre[16|32]_study() to be called after the
488 expression has been compiled, and the results used when the expression
489 is matched. There are a number of qualifying characters that may follow
490 /S. They may appear in any order.
491
492 If S is followed by an exclamation mark, pcre[16|32]_study() is called
493 with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
494 pcre_extra block, even when studying discovers no useful information.
495
496 If /S is followed by a second S character, it suppresses studying, even
497 if it was requested externally by the -s command line option. This
498 makes it possible to specify that certain patterns are always studied,
499 and others are never studied, independently of -s. This feature is used
500 in the test files in a few cases where the output is different when the
501 pattern is studied.
502
503 If the /S modifier is followed by a + character, the call to
504 pcre[16|32]_study() is made with all the JIT study options, requesting
505 just-in-time optimization support if it is available, for both normal
506 and partial matching. If you want to restrict the JIT compiling modes,
507 you can follow /S+ with a digit in the range 1 to 7:
508
509 1 normal match only
510 2 soft partial match only
511 3 normal match and soft partial match
512 4 hard partial match only
513 6 soft and hard partial match
514 7 all three modes (default)
515
516 If /S++ is used instead of /S+ (with or without a following digit), the
517 text "(JIT)" is added to the first output line after a match or no
518 match when JIT-compiled code was actually used.
519
520 Note that there is also an independent /+ modifier; it must not be
521 given immediately after /S or /S+ because this will be misinterpreted.
522
523 If JIT studying is successful, the compiled JIT code will automatically
524 be used when pcre[16|32]_exec() is run, except when incompatible run-
525 time options are specified. For more details, see the pcrejit documen-
526 tation. See also the \J escape sequence below for a way of setting the
527 size of the JIT stack.
528
529 Finally, if /S is followed by a minus character, JIT compilation is
530 suppressed, even if it was requested externally by the -s command line
531 option. This makes it possible to specify that JIT is never to be used
532 for certain patterns.
533
534 The /T modifier must be followed by a single digit. It causes a spe-
535 cific set of built-in character tables to be passed to pcre[16|32]_com-
536 pile(). It is used in the standard PCRE tests to check behaviour with
537 different character tables. The digit specifies the tables as follows:
538
539 0 the default ASCII tables, as distributed in
540 pcre_chartables.c.dist
541 1 a set of tables defining ISO 8859 characters
542
543 In table 1, some characters whose codes are greater than 128 are iden-
544 tified as letters, digits, spaces, etc.
545
546 Using the POSIX wrapper API
547
548 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
549 rather than its native API. This supports only the 8-bit library. When
550 /P is set, the following modifiers set options for the regcomp() func-
551 tion:
552
553 /i REG_ICASE
554 /m REG_NEWLINE
555 /N REG_NOSUB
556 /s REG_DOTALL )
557 /U REG_UNGREEDY ) These options are not part of
558 /W REG_UCP ) the POSIX standard
559 /8 REG_UTF8 )
560
561 The /+ modifier works as described above. All other modifiers are
562 ignored.
563
564
565 DATA LINES
566
567 Before each data line is passed to pcre[16|32]_exec(), leading and
568 trailing white space is removed, and it is then scanned for \ escapes.
569 Some of these are pretty esoteric features, intended for checking out
570 some of the more complicated features of PCRE. If you are just testing
571 "ordinary" regular expressions, you probably don't need any of these.
572 The following escapes are recognized:
573
574 \a alarm (BEL, \x07)
575 \b backspace (\x08)
576 \e escape (\x27)
577 \f form feed (\x0c)
578 \n newline (\x0a)
579 \qdd set the PCRE_MATCH_LIMIT limit to dd
580 (any number of digits)
581 \r carriage return (\x0d)
582 \t tab (\x09)
583 \v vertical tab (\x0b)
584 \nnn octal character (up to 3 octal digits); always
585 a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode
586 \xhh hexadecimal byte (up to 2 hex digits)
587 \x{hh...} hexadecimal character (any number of hex digits)
588 \A pass the PCRE_ANCHORED option to pcre[16|32]_exec()
589 or pcre[16|32]_dfa_exec()
590 \B pass the PCRE_NOTBOL option to pcre[16|32]_exec()
591 or pcre[16|32]_dfa_exec()
592 \Cdd call pcre[16|32]_copy_substring() for substring dd
593 after a successful match (number less than 32)
594 \Cname call pcre[16|32]_copy_named_substring() for substring
595 "name" after a successful match (name termin-
596 ated by next non alphanumeric character)
597 \C+ show the current captured substrings at callout
598 time
599 \C- do not supply a callout function
600 \C!n return 1 instead of 0 when callout number n is
601 reached
602 \C!n!m return 1 instead of 0 when callout number n is
603 reached for the nth time
604 \C*n pass the number n (may be negative) as callout
605 data; this is used as the callout return value
606 \D use the pcre[16|32]_dfa_exec() match function
607 \F only shortest match for pcre[16|32]_dfa_exec()
608 \Gdd call pcre[16|32]_get_substring() for substring dd
609 after a successful match (number less than 32)
610 \Gname call pcre[16|32]_get_named_substring() for substring
611 "name" after a successful match (name termin-
612 ated by next non-alphanumeric character)
613 \Jdd set up a JIT stack of dd kilobytes maximum (any
614 number of digits)
615 \L call pcre[16|32]_get_substringlist() after a
616 successful match
617 \M discover the minimum MATCH_LIMIT and
618 MATCH_LIMIT_RECURSION settings
619 \N pass the PCRE_NOTEMPTY option to pcre[16|32]_exec()
620 or pcre[16|32]_dfa_exec(); if used twice, pass the
621 PCRE_NOTEMPTY_ATSTART option
622 \Odd set the size of the output vector passed to
623 pcre[16|32]_exec() to dd (any number of digits)
624 \P pass the PCRE_PARTIAL_SOFT option to pcre[16|32]_exec()
625 or pcre[16|32]_dfa_exec(); if used twice, pass the
626 PCRE_PARTIAL_HARD option
627 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
628 (any number of digits)
629 \R pass the PCRE_DFA_RESTART option to pcre[16|32]_dfa_exec()
630 \S output details of memory get/free calls during matching
631 \Y pass the PCRE_NO_START_OPTIMIZE option to
632 pcre[16|32]_exec()
633 or pcre[16|32]_dfa_exec()
634 \Z pass the PCRE_NOTEOL option to pcre[16|32]_exec()
635 or pcre[16|32]_dfa_exec()
636 \? pass the PCRE_NO_UTF[8|16|32]_CHECK option to
637 pcre[16|32]_exec() or pcre[16|32]_dfa_exec()
638 \>dd start the match at offset dd (optional "-"; then
639 any number of digits); this sets the startoffset
640 argument for pcre[16|32]_exec() or
641 pcre[16|32]_dfa_exec()
642 \<cr> pass the PCRE_NEWLINE_CR option to pcre[16|32]_exec()
643 or pcre[16|32]_dfa_exec()
644 \<lf> pass the PCRE_NEWLINE_LF option to pcre[16|32]_exec()
645 or pcre[16|32]_dfa_exec()
646 \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre[16|32]_exec()
647 or pcre[16|32]_dfa_exec()
648 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16|32]_exec()
649 or pcre[16|32]_dfa_exec()
650 \<any> pass the PCRE_NEWLINE_ANY option to pcre[16|32]_exec()
651 or pcre[16|32]_dfa_exec()
652
653 The use of \x{hh...} is not dependent on the use of the /8 modifier on
654 the pattern. It is recognized always. There may be any number of hexa-
655 decimal digits inside the braces; invalid values provoke error mes-
656 sages.
657
658 Note that \xhh specifies one byte rather than one character in UTF-8
659 mode; this makes it possible to construct invalid UTF-8 sequences for
660 testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8
661 character in UTF-8 mode, generating more than one byte if the value is
662 greater than 127. When testing the 8-bit library not in UTF-8 mode,
663 \x{hh} generates one byte for values less than 256, and causes an error
664 for greater values.
665
666 In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
667 possible to construct invalid UTF-16 sequences for testing purposes.
668
669 In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This
670 makes it possible to construct invalid UTF-32 sequences for testing
671 purposes.
672
673 The escapes that specify line ending sequences are literal strings,
674 exactly as shown. No more than one newline setting should be present in
675 any data line.
676
677 A backslash followed by anything else just escapes the anything else.
678 If the very last character is a backslash, it is ignored. This gives a
679 way of passing an empty line as data, since a real empty line termi-
680 nates the data input.
681
682 The \J escape provides a way of setting the maximum stack size that is
683 used by the just-in-time optimization code. It is ignored if JIT opti-
684 mization is not being used. Providing a stack that is larger than the
685 default 32K is necessary only for very complicated patterns.
686
687 If \M is present, pcretest calls pcre[16|32]_exec() several times, with
688 different values in the match_limit and match_limit_recursion fields of
689 the pcre[16|32]_extra data structure, until it finds the minimum num-
690 bers for each parameter that allow pcre[16|32]_exec() to complete with-
691 out error. Because this is testing a specific feature of the normal
692 interpretive pcre[16|32]_exec() execution, the use of any JIT optimiza-
693 tion that might have been set up by the /S+ qualifier of -s+ option is
694 disabled.
695
696 The match_limit number is a measure of the amount of backtracking that
697 takes place, and checking it out can be instructive. For most simple
698 matches, the number is quite small, but for patterns with very large
699 numbers of matching possibilities, it can become large very quickly
700 with increasing length of subject string. The match_limit_recursion
701 number is a measure of how much stack (or, if PCRE is compiled with
702 NO_RECURSE, how much heap) memory is needed to complete the match
703 attempt.
704
705 When \O is used, the value specified may be higher or lower than the
706 size set by the -O command line option (or defaulted to 45); \O applies
707 only to the call of pcre[16|32]_exec() for the line in which it
708 appears.
709
710 If the /P modifier was present on the pattern, causing the POSIX wrap-
711 per API to be used, the only option-setting sequences that have any
712 effect are \B, \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and
713 REG_NOTEOL, respectively, to be passed to regexec().
714
715
716 THE ALTERNATIVE MATCHING FUNCTION
717
718 By default, pcretest uses the standard PCRE matching function,
719 pcre[16|32]_exec() to match each data line. PCRE also supports an
720 alternative matching function, pcre[16|32]_dfa_test(), which operates
721 in a different way, and has some restrictions. The differences between
722 the two functions are described in the pcrematching documentation.
723
724 If a data line contains the \D escape sequence, or if the command line
725 contains the -dfa option, the alternative matching function is used.
726 This function finds all possible matches at a given point. If, however,
727 the \F escape sequence is present in the data line, it stops after the
728 first match is found. This is always the shortest possible match.
729
730
731 DEFAULT OUTPUT FROM PCRETEST
732
733 This section describes the output when the normal matching function,
734 pcre[16|32]_exec(), is being used.
735
736 When a match succeeds, pcretest outputs the list of captured substrings
737 that pcre[16|32]_exec() returns, starting with number 0 for the string
738 that matched the whole pattern. Otherwise, it outputs "No match" when
739 the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the
740 partially matching substring when pcre[16|32]_exec() returns
741 PCRE_ERROR_PARTIAL. (Note that this is the entire substring that was
742 inspected during the partial match; it may include characters before
743 the actual match start if a lookbehind assertion, \K, \b, or \B was
744 involved.) For any other return, pcretest outputs the PCRE negative
745 error number and a short descriptive phrase. If the error is a failed
746 UTF string check, the offset of the start of the failing character and
747 the reason code are also output, provided that the size of the output
748 vector is at least two. Here is an example of an interactive pcretest
749 run.
750
751 $ pcretest
752 PCRE version 8.13 2011-04-30
753
754 re> /^abc(\d+)/
755 data> abc123
756 0: abc123
757 1: 123
758 data> xyz
759 No match
760
761 Unset capturing substrings that are not followed by one that is set are
762 not returned by pcre[16|32]_exec(), and are not shown by pcretest. In
763 the following example, there are two capturing substrings, but when the
764 first data line is matched, the second, unset substring is not shown.
765 An "internal" unset substring is shown as "<unset>", as for the second
766 data line.
767
768 re> /(a)|(b)/
769 data> a
770 0: a
771 1: a
772 data> b
773 0: b
774 1: <unset>
775 2: b
776
777 If the strings contain any non-printing characters, they are output as
778 \xhh escapes if the value is less than 256 and UTF mode is not set.
779 Otherwise they are output as \x{hh...} escapes. See below for the defi-
780 nition of non-printing characters. If the pattern has the /+ modifier,
781 the output for substring 0 is followed by the the rest of the subject
782 string, identified by "0+" like this:
783
784 re> /cat/+
785 data> cataract
786 0: cat
787 0+ aract
788
789 If the pattern has the /g or /G modifier, the results of successive
790 matching attempts are output in sequence, like this:
791
792 re> /\Bi(\w\w)/g
793 data> Mississippi
794 0: iss
795 1: ss
796 0: iss
797 1: ss
798 0: ipp
799 1: pp
800
801 "No match" is output only if the first match attempt fails. Here is an
802 example of a failure message (the offset 4 that is specified by \>4 is
803 past the end of the subject string):
804
805 re> /xyz/
806 data> xyz\>4
807 Error -24 (bad offset value)
808
809 If any of the sequences \C, \G, or \L are present in a data line that
810 is successfully matched, the substrings extracted by the convenience
811 functions are output with C, G, or L after the string number instead of
812 a colon. This is in addition to the normal full list. The string length
813 (that is, the return from the extraction function) is given in paren-
814 theses after each string for \C and \G.
815
816 Note that whereas patterns can be continued over several lines (a plain
817 ">" prompt is used for continuations), data lines may not. However new-
818 lines can be included in data by means of the \n escape (or \r, \r\n,
819 etc., depending on the newline sequence setting).
820
821
822 OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
823
824 When the alternative matching function, pcre[16|32]_dfa_exec(), is used
825 (by means of the \D escape sequence or the -dfa command line option),
826 the output consists of a list of all the matches that start at the
827 first point in the subject where there is at least one match. For exam-
828 ple:
829
830 re> /(tang|tangerine|tan)/
831 data> yellow tangerine\D
832 0: tangerine
833 1: tang
834 2: tan
835
836 (Using the normal matching function on this data finds only "tang".)
837 The longest matching string is always given first (and numbered zero).
838 After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
839 lowed by the partially matching substring. (Note that this is the
840 entire substring that was inspected during the partial match; it may
841 include characters before the actual match start if a lookbehind asser-
842 tion, \K, \b, or \B was involved.)
843
844 If /g is present on the pattern, the search for further matches resumes
845 at the end of the longest match. For example:
846
847 re> /(tang|tangerine|tan)/g
848 data> yellow tangerine and tangy sultana\D
849 0: tangerine
850 1: tang
851 2: tan
852 0: tang
853 1: tan
854 0: tan
855
856 Since the matching function does not support substring capture, the
857 escape sequences that are concerned with captured substrings are not
858 relevant.
859
860
861 RESTARTING AFTER A PARTIAL MATCH
862
863 When the alternative matching function has given the PCRE_ERROR_PARTIAL
864 return, indicating that the subject partially matched the pattern, you
865 can restart the match with additional subject data by means of the \R
866 escape sequence. For example:
867
868 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
869 data> 23ja\P\D
870 Partial match: 23ja
871 data> n05\R\D
872 0: n05
873
874 For further information about partial matching, see the pcrepartial
875 documentation.
876
877
878 CALLOUTS
879
880 If the pattern contains any callout requests, pcretest's callout func-
881 tion is called during matching. This works with both matching func-
882 tions. By default, the called function displays the callout number, the
883 start and current positions in the text at the callout time, and the
884 next pattern item to be tested. For example:
885
886 --->pqrabcdef
887 0 ^ ^ \d
888
889 This output indicates that callout number 0 occurred for a match
890 attempt starting at the fourth character of the subject string, when
891 the pointer was at the seventh character of the data, and when the next
892 pattern item was \d. Just one circumflex is output if the start and
893 current positions are the same.
894
895 Callouts numbered 255 are assumed to be automatic callouts, inserted as
896 a result of the /C pattern modifier. In this case, instead of showing
897 the callout number, the offset in the pattern, preceded by a plus, is
898 output. For example:
899
900 re> /\d?[A-E]\*/C
901 data> E*
902 --->E*
903 +0 ^ \d?
904 +3 ^ [A-E]
905 +8 ^^ \*
906 +10 ^ ^
907 0: E*
908
909 If a pattern contains (*MARK) items, an additional line is output when-
910 ever a change of latest mark is passed to the callout function. For
911 example:
912
913 re> /a(*MARK:X)bc/C
914 data> abc
915 --->abc
916 +0 ^ a
917 +1 ^^ (*MARK:X)
918 +10 ^^ b
919 Latest Mark: X
920 +11 ^ ^ c
921 +12 ^ ^
922 0: abc
923
924 The mark changes between matching "a" and "b", but stays the same for
925 the rest of the match, so nothing more is output. If, as a result of
926 backtracking, the mark reverts to being unset, the text "<unset>" is
927 output.
928
929 The callout function in pcretest returns zero (carry on matching) by
930 default, but you can use a \C item in a data line (as described above)
931 to change this and other parameters of the callout.
932
933 Inserting callouts can be helpful when using pcretest to check compli-
934 cated regular expressions. For further information about callouts, see
935 the pcrecallout documentation.
936
937
938 NON-PRINTING CHARACTERS
939
940 When pcretest is outputting text in the compiled version of a pattern,
941 bytes other than 32-126 are always treated as non-printing characters
942 are are therefore shown as hex escapes.
943
944 When pcretest is outputting text that is a matched part of a subject
945 string, it behaves in the same way, unless a different locale has been
946 set for the pattern (using the /L modifier). In this case, the
947 isprint() function to distinguish printing and non-printing characters.
948
949
950 SAVING AND RELOADING COMPILED PATTERNS
951
952 The facilities described in this section are not available when the
953 POSIX interface to PCRE is being used, that is, when the /P pattern
954 modifier is specified.
955
956 When the POSIX interface is not in use, you can cause pcretest to write
957 a compiled pattern to a file, by following the modifiers with > and a
958 file name. For example:
959
960 /pattern/im >/some/file
961
962 See the pcreprecompile documentation for a discussion about saving and
963 re-using compiled patterns. Note that if the pattern was successfully
964 studied with JIT optimization, the JIT data cannot be saved.
965
966 The data that is written is binary. The first eight bytes are the
967 length of the compiled pattern data followed by the length of the
968 optional study data, each written as four bytes in big-endian order
969 (most significant byte first). If there is no study data (either the
970 pattern was not studied, or studying did not return any data), the sec-
971 ond length is zero. The lengths are followed by an exact copy of the
972 compiled pattern. If there is additional study data, this (excluding
973 any JIT data) follows immediately after the compiled pattern. After
974 writing the file, pcretest expects to read a new pattern.
975
976 A saved pattern can be reloaded into pcretest by specifying < and a
977 file name instead of a pattern. The name of the file must not contain a
978 < character, as otherwise pcretest will interpret the line as a pattern
979 delimited by < characters. For example:
980
981 re> </some/file
982 Compiled pattern loaded from /some/file
983 No study data
984
985 If the pattern was previously studied with the JIT optimization, the
986 JIT information cannot be saved and restored, and so is lost. When the
987 pattern has been loaded, pcretest proceeds to read data lines in the
988 usual way.
989
990 You can copy a file written by pcretest to a different host and reload
991 it there, even if the new host has opposite endianness to the one on
992 which the pattern was compiled. For example, you can compile on an i86
993 machine and run on a SPARC machine. When a pattern is reloaded on a
994 host with different endianness, the confirmation message is changed to:
995
996 Compiled pattern (byte-inverted) loaded from /some/file
997
998 The test suite contains some saved pre-compiled patterns with different
999 endianness. These are reloaded using "<!" instead of just "<". This
1000 suppresses the "(byte-inverted)" text so that the output is the same on
1001 all hosts. It also forces debugging output once the pattern has been
1002 reloaded.
1003
1004 File names for saving and reloading can be absolute or relative, but
1005 note that the shell facility of expanding a file name that starts with
1006 a tilde (~) is not available.
1007
1008 The ability to save and reload files in pcretest is intended for test-
1009 ing and experimentation. It is not intended for production use because
1010 only a single pattern can be written to a file. Furthermore, there is
1011 no facility for supplying custom character tables for use with a
1012 reloaded pattern. If the original pattern was compiled with custom
1013 tables, an attempt to match a subject string using a reloaded pattern
1014 is likely to cause pcretest to crash. Finally, if you attempt to load
1015 a file that is not in the correct format, the result is undefined.
1016
1017
1018 SEE ALSO
1019
1020 pcre(3), pcre16(3), pcre32(3), pcreapi(3), pcrecallout(3), pcrejit,
1021 pcrematching(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
1022
1023
1024 AUTHOR
1025
1026 Philip Hazel
1027 University Computing Service
1028 Cambridge CB2 3QH, England.
1029
1030
1031 REVISION
1032
1033 Last updated: 26 April 2013
1034 Copyright (c) 1997-2013 University of Cambridge.

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