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1 .TH PCRETEST 1 "28 August 2012" "PCRE 8.32"
3 pcretest - a program for testing Perl-compatible regular expressions.
5 .rs
6 .sp
7 .B pcretest "[options] [input file [output file]]"
8 .sp
9 \fBpcretest\fP was written as a test program for the PCRE regular expression
10 library itself, but it can also be used for experimenting with regular
11 expressions. This document describes the features of the test program; for
12 details of the regular expressions themselves, see the
13 .\" HREF
14 \fBpcrepattern\fP
15 .\"
16 documentation. For details of the PCRE library function calls and their
17 options, see the
18 .\" HREF
19 \fBpcreapi\fP
20 .\"
21 and
22 .\" HREF
23 \fBpcre16\fP
24 .\"
25 documentation.
26 .P
27 The input for \fBpcretest\fP is a sequence of regular expression patterns and
28 strings to be matched, as described below. The output shows the result of each
29 match. Options on the command line and the patterns control PCRE options and
30 exactly what is output.
31 .P
32 As PCRE has evolved, it has acquired many different features, and as a result,
33 \fBpcretest\fP now has rather a lot of obscure options for testing every
34 possible feature. Some of these options are specifically designed for use in
35 conjunction with the test script and data files that are distributed as part of
36 PCRE, and are unlikely to be of use otherwise. They are all documented here,
37 but without much justification.
38 .
39 .
40 .SH "PCRE's 8-BIT and 16-BIT LIBRARIES"
41 .rs
42 .sp
43 From release 8.30, two separate PCRE libraries can be built. The original one
44 supports 8-bit character strings, whereas the newer 16-bit library supports
45 character strings encoded in 16-bit units. The \fBpcretest\fP program can be
46 used to test both libraries. However, it is itself still an 8-bit program,
47 reading 8-bit input and writing 8-bit output. When testing the 16-bit library,
48 the patterns and data strings are converted to 16-bit format before being
49 passed to the PCRE library functions. Results are converted to 8-bit for
50 output.
51 .P
52 References to functions and structures of the form \fBpcre[16]_xx\fP below
53 mean "\fBpcre_xx\fP when using the 8-bit library or \fBpcre16_xx\fP when using
54 the 16-bit library".
55 .
56 .
58 .rs
59 .TP 10
60 \fB-16\fP
61 If both the 8-bit and the 16-bit libraries have been built, this option causes
62 the 16-bit library to be used. If only the 16-bit library has been built, this
63 is the default (so has no effect). If only the 8-bit library has been built,
64 this option causes an error.
65 .TP 10
66 \fB-b\fP
67 Behave as if each pattern has the \fB/B\fP (show byte code) modifier; the
68 internal form is output after compilation.
69 .TP 10
70 \fB-C\fP
71 Output the version number of the PCRE library, and all available information
72 about the optional features that are included, and then exit. All other options
73 are ignored.
74 .TP 10
75 \fB-C\fP \fIoption\fP
76 Output information about a specific build-time option, then exit. This
77 functionality is intended for use in scripts such as \fBRunTest\fP. The
78 following options output the value indicated:
79 .sp
80 linksize the internal link size (2, 3, or 4)
81 newline the default newline setting:
83 .sp
84 The following options output 1 for true or zero for false:
85 .sp
86 jit just-in-time support is available
87 pcre16 the 16-bit library was built
88 pcre8 the 8-bit library was built
89 ucp Unicode property support is available
90 utf UTF-8 and/or UTF-16 support is available
91 .TP 10
92 \fB-d\fP
93 Behave as if each pattern has the \fB/D\fP (debug) modifier; the internal
94 form and information about the compiled pattern is output after compilation;
95 \fB-d\fP is equivalent to \fB-b -i\fP.
96 .TP 10
97 \fB-dfa\fP
98 Behave as if each data line contains the \eD escape sequence; this causes the
99 alternative matching function, \fBpcre[16]_dfa_exec()\fP, to be used instead of
100 the standard \fBpcre[16]_exec()\fP function (more detail is given below).
101 .TP 10
102 \fB-help\fP
103 Output a brief summary these options and then exit.
104 .TP 10
105 \fB-i\fP
106 Behave as if each pattern has the \fB/I\fP modifier; information about the
107 compiled pattern is given after compilation.
108 .TP 10
109 \fB-M\fP
110 Behave as if each data line contains the \eM escape sequence; this causes
111 PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by
112 calling \fBpcre[16]_exec()\fP repeatedly with different limits.
113 .TP 10
114 \fB-m\fP
115 Output the size of each compiled pattern after it has been compiled. This is
116 equivalent to adding \fB/M\fP to each regular expression. The size is given in
117 bytes for both libraries.
118 .TP 10
119 \fB-o\fP \fIosize\fP
120 Set the number of elements in the output vector that is used when calling
121 \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP to be \fIosize\fP. The
122 default value is 45, which is enough for 14 capturing subexpressions for
123 \fBpcre[16]_exec()\fP or 22 different matches for \fBpcre[16]_dfa_exec()\fP.
124 The vector size can be changed for individual matching calls by including \eO
125 in the data line (see below).
126 .TP 10
127 \fB-p\fP
128 Behave as if each pattern has the \fB/P\fP modifier; the POSIX wrapper API is
129 used to call PCRE. None of the other options has any effect when \fB-p\fP is
130 set. This option can be used only with the 8-bit library.
131 .TP 10
132 \fB-q\fP
133 Do not output the version number of \fBpcretest\fP at the start of execution.
134 .TP 10
135 \fB-S\fP \fIsize\fP
136 On Unix-like systems, set the size of the run-time stack to \fIsize\fP
137 megabytes.
138 .TP 10
139 \fB-s\fP or \fB-s+\fP
140 Behave as if each pattern has the \fB/S\fP modifier; in other words, force each
141 pattern to be studied. If \fB-s+\fP is used, all the JIT compile options are
142 passed to \fBpcre[16]_study()\fP, causing just-in-time optimization to be set
143 up if it is available, for both full and partial matching. Specific JIT compile
144 options can be selected by following \fB-s+\fP with a digit in the range 1 to
145 7, which selects the JIT compile modes as follows:
146 .sp
147 1 normal match only
148 2 soft partial match only
149 3 normal match and soft partial match
150 4 hard partial match only
151 6 soft and hard partial match
152 7 all three modes (default)
153 .sp
154 If \fB-s++\fP is used instead of \fB-s+\fP (with or without a following digit),
155 the text "(JIT)" is added to the first output line after a match or no match
156 when JIT-compiled code was actually used.
157 .sp
158 Note that there are pattern options that can override \fB-s\fP, either
159 specifying no studying at all, or suppressing JIT compilation.
160 .sp
161 If the \fB/I\fP or \fB/D\fP option is present on a pattern (requesting output
162 about the compiled pattern), information about the result of studying is not
163 included when studying is caused only by \fB-s\fP and neither \fB-i\fP nor
164 \fB-d\fP is present on the command line. This behaviour means that the output
165 from tests that are run with and without \fB-s\fP should be identical, except
166 when options that output information about the actual running of a match are
167 set.
168 .sp
169 The \fB-M\fP, \fB-t\fP, and \fB-tm\fP options, which give information about
170 resources used, are likely to produce different output with and without
171 \fB-s\fP. Output may also differ if the \fB/C\fP option is present on an
172 individual pattern. This uses callouts to trace the the matching process, and
173 this may be different between studied and non-studied patterns. If the pattern
174 contains (*MARK) items there may also be differences, for the same reason. The
175 \fB-s\fP command line option can be overridden for specific patterns that
176 should never be studied (see the \fB/S\fP pattern modifier below).
177 .TP 10
178 \fB-t\fP
179 Run each compile, study, and match many times with a timer, and output
180 resulting time per compile or match (in milliseconds). Do not set \fB-m\fP with
181 \fB-t\fP, because you will then get the size output a zillion times, and the
182 timing will be distorted. You can control the number of iterations that are
183 used for timing by following \fB-t\fP with a number (as a separate item on the
184 command line). For example, "-t 1000" would iterate 1000 times. The default is
185 to iterate 500000 times.
186 .TP 10
187 \fB-tm\fP
188 This is like \fB-t\fP except that it times only the matching phase, not the
189 compile or study phases.
190 .
191 .
193 .rs
194 .sp
195 If \fBpcretest\fP is given two filename arguments, it reads from the first and
196 writes to the second. If it is given only one filename argument, it reads from
197 that file and writes to stdout. Otherwise, it reads from stdin and writes to
198 stdout, and prompts for each line of input, using "re>" to prompt for regular
199 expressions, and "data>" to prompt for data lines.
200 .P
201 When \fBpcretest\fP is built, a configuration option can specify that it should
202 be linked with the \fBlibreadline\fP library. When this is done, if the input
203 is from a terminal, it is read using the \fBreadline()\fP function. This
204 provides line-editing and history facilities. The output from the \fB-help\fP
205 option states whether or not \fBreadline()\fP will be used.
206 .P
207 The program handles any number of sets of input on a single input file. Each
208 set starts with a regular expression, and continues with any number of data
209 lines to be matched against the pattern.
210 .P
211 Each data line is matched separately and independently. If you want to do
212 multi-line matches, you have to use the \en escape sequence (or \er or \er\en,
213 etc., depending on the newline setting) in a single line of input to encode the
214 newline sequences. There is no limit on the length of data lines; the input
215 buffer is automatically extended if it is too small.
216 .P
217 An empty line signals the end of the data lines, at which point a new regular
218 expression is read. The regular expressions are given enclosed in any
219 non-alphanumeric delimiters other than backslash, for example:
220 .sp
221 /(a|bc)x+yz/
222 .sp
223 White space before the initial delimiter is ignored. A regular expression may
224 be continued over several input lines, in which case the newline characters are
225 included within it. It is possible to include the delimiter within the pattern
226 by escaping it, for example
227 .sp
228 /abc\e/def/
229 .sp
230 If you do so, the escape and the delimiter form part of the pattern, but since
231 delimiters are always non-alphanumeric, this does not affect its interpretation.
232 If the terminating delimiter is immediately followed by a backslash, for
233 example,
234 .sp
235 /abc/\e
236 .sp
237 then a backslash is added to the end of the pattern. This is done to provide a
238 way of testing the error condition that arises if a pattern finishes with a
239 backslash, because
240 .sp
241 /abc\e/
242 .sp
243 is interpreted as the first line of a pattern that starts with "abc/", causing
244 pcretest to read the next line as a continuation of the regular expression.
245 .
246 .
248 .rs
249 .sp
250 A pattern may be followed by any number of modifiers, which are mostly single
251 characters. Following Perl usage, these are referred to below as, for example,
252 "the \fB/i\fP modifier", even though the delimiter of the pattern need not
253 always be a slash, and no slash is used when writing modifiers. White space may
254 appear between the final pattern delimiter and the first modifier, and between
255 the modifiers themselves.
256 .P
257 The \fB/i\fP, \fB/m\fP, \fB/s\fP, and \fB/x\fP modifiers set the PCRE_CASELESS,
258 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
259 \fBpcre[16]_compile()\fP is called. These four modifier letters have the same
260 effect as they do in Perl. For example:
261 .sp
262 /caseless/i
263 .sp
264 The following table shows additional modifiers for setting PCRE compile-time
265 options that do not correspond to anything in Perl:
266 .sp
267 \fB/8\fP PCRE_UTF8 ) when using the 8-bit
268 \fB/?\fP PCRE_NO_UTF8_CHECK ) library
269 .sp
270 \fB/8\fP PCRE_UTF16 ) when using the 16-bit
271 \fB/?\fP PCRE_NO_UTF16_CHECK ) library
272 .sp
280 \fB/W\fP PCRE_UCP
284 \fB/<cr>\fP PCRE_NEWLINE_CR
285 \fB/<lf>\fP PCRE_NEWLINE_LF
286 \fB/<crlf>\fP PCRE_NEWLINE_CRLF
287 \fB/<anycrlf>\fP PCRE_NEWLINE_ANYCRLF
288 \fB/<any>\fP PCRE_NEWLINE_ANY
289 \fB/<bsr_anycrlf>\fP PCRE_BSR_ANYCRLF
290 \fB/<bsr_unicode>\fP PCRE_BSR_UNICODE
291 .sp
292 The modifiers that are enclosed in angle brackets are literal strings as shown,
293 including the angle brackets, but the letters within can be in either case.
294 This example sets multiline matching with CRLF as the line ending sequence:
295 .sp
296 /^abc/m<CRLF>
297 .sp
298 As well as turning on the PCRE_UTF8/16 option, the \fB/8\fP modifier causes
299 all non-printing characters in output strings to be printed using the
300 \ex{hh...} notation. Otherwise, those less than 0x100 are output in hex without
301 the curly brackets.
302 .P
303 Full details of the PCRE options are given in the
304 .\" HREF
305 \fBpcreapi\fP
306 .\"
307 documentation.
308 .
309 .
310 .SS "Finding all matches in a string"
311 .rs
312 .sp
313 Searching for all possible matches within each subject string can be requested
314 by the \fB/g\fP or \fB/G\fP modifier. After finding a match, PCRE is called
315 again to search the remainder of the subject string. The difference between
316 \fB/g\fP and \fB/G\fP is that the former uses the \fIstartoffset\fP argument to
317 \fBpcre[16]_exec()\fP to start searching at a new point within the entire
318 string (which is in effect what Perl does), whereas the latter passes over a
319 shortened substring. This makes a difference to the matching process if the
320 pattern begins with a lookbehind assertion (including \eb or \eB).
321 .P
322 If any call to \fBpcre[16]_exec()\fP in a \fB/g\fP or \fB/G\fP sequence matches
323 an empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
324 PCRE_ANCHORED flags set in order to search for another, non-empty, match at the
325 same point. If this second match fails, the start offset is advanced, and the
326 normal match is retried. This imitates the way Perl handles such cases when
327 using the \fB/g\fP modifier or the \fBsplit()\fP function. Normally, the start
328 offset is advanced by one character, but if the newline convention recognizes
329 CRLF as a newline, and the current character is CR followed by LF, an advance
330 of two is used.
331 .
332 .
333 .SS "Other modifiers"
334 .rs
335 .sp
336 There are yet more modifiers for controlling the way \fBpcretest\fP
337 operates.
338 .P
339 The \fB/+\fP modifier requests that as well as outputting the substring that
340 matched the entire pattern, \fBpcretest\fP should in addition output the
341 remainder of the subject string. This is useful for tests where the subject
342 contains multiple copies of the same substring. If the \fB+\fP modifier appears
343 twice, the same action is taken for captured substrings. In each case the
344 remainder is output on the following line with a plus character following the
345 capture number. Note that this modifier must not immediately follow the /S
346 modifier because /S+ and /S++ have other meanings.
347 .P
348 The \fB/=\fP modifier requests that the values of all potential captured
349 parentheses be output after a match. By default, only those up to the highest
350 one actually used in the match are output (corresponding to the return code
351 from \fBpcre[16]_exec()\fP). Values in the offsets vector corresponding to
352 higher numbers should be set to -1, and these are output as "<unset>". This
353 modifier gives a way of checking that this is happening.
354 .P
355 The \fB/B\fP modifier is a debugging feature. It requests that \fBpcretest\fP
356 output a representation of the compiled code after compilation. Normally this
357 information contains length and offset values; however, if \fB/Z\fP is also
358 present, this data is replaced by spaces. This is a special feature for use in
359 the automatic test scripts; it ensures that the same output is generated for
360 different internal link sizes.
361 .P
362 The \fB/D\fP modifier is a PCRE debugging feature, and is equivalent to
363 \fB/BI\fP, that is, both the \fB/B\fP and the \fB/I\fP modifiers.
364 .P
365 The \fB/F\fP modifier causes \fBpcretest\fP to flip the byte order of the
366 2-byte and 4-byte fields in the compiled pattern. This facility is for testing
367 the feature in PCRE that allows it to execute patterns that were compiled on a
368 host with a different endianness. This feature is not available when the POSIX
369 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
370 specified. See also the section about saving and reloading compiled patterns
371 below.
372 .P
373 The \fB/I\fP modifier requests that \fBpcretest\fP output information about the
374 compiled pattern (whether it is anchored, has a fixed first character, and
375 so on). It does this by calling \fBpcre[16]_fullinfo()\fP after compiling a
376 pattern. If the pattern is studied, the results of that are also output.
377 .P
378 The \fB/K\fP modifier requests \fBpcretest\fP to show names from backtracking
379 control verbs that are returned from calls to \fBpcre[16]_exec()\fP. It causes
380 \fBpcretest\fP to create a \fBpcre[16]_extra\fP block if one has not already
381 been created by a call to \fBpcre[16]_study()\fP, and to set the
382 PCRE_EXTRA_MARK flag and the \fBmark\fP field within it, every time that
383 \fBpcre[16]_exec()\fP is called. If the variable that the \fBmark\fP field
384 points to is non-NULL for a match, non-match, or partial match, \fBpcretest\fP
385 prints the string to which it points. For a match, this is shown on a line by
386 itself, tagged with "MK:". For a non-match it is added to the message.
387 .P
388 The \fB/L\fP modifier must be followed directly by the name of a locale, for
389 example,
390 .sp
391 /pattern/Lfr_FR
392 .sp
393 For this reason, it must be the last modifier. The given locale is set,
394 \fBpcre[16]_maketables()\fP is called to build a set of character tables for
395 the locale, and this is then passed to \fBpcre[16]_compile()\fP when compiling
396 the regular expression. Without an \fB/L\fP (or \fB/T\fP) modifier, NULL is
397 passed as the tables pointer; that is, \fB/L\fP applies only to the expression
398 on which it appears.
399 .P
400 The \fB/M\fP modifier causes the size in bytes of the memory block used to hold
401 the compiled pattern to be output. This does not include the size of the
402 \fBpcre[16]\fP block; it is just the actual compiled data. If the pattern is
403 successfully studied with the PCRE_STUDY_JIT_COMPILE option, the size of the
404 JIT compiled code is also output.
405 .P
406 The \fB/S\fP modifier causes \fBpcre[16]_study()\fP to be called after the
407 expression has been compiled, and the results used when the expression is
408 matched. There are a number of qualifying characters that may follow \fB/S\fP.
409 They may appear in any order.
410 .P
411 If \fBS\fP is followed by an exclamation mark, \fBpcre[16]_study()\fP is called
412 with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
413 \fBpcre_extra\fP block, even when studying discovers no useful information.
414 .P
415 If \fB/S\fP is followed by a second S character, it suppresses studying, even
416 if it was requested externally by the \fB-s\fP command line option. This makes
417 it possible to specify that certain patterns are always studied, and others are
418 never studied, independently of \fB-s\fP. This feature is used in the test
419 files in a few cases where the output is different when the pattern is studied.
420 .P
421 If the \fB/S\fP modifier is followed by a + character, the call to
422 \fBpcre[16]_study()\fP is made with all the JIT study options, requesting
423 just-in-time optimization support if it is available, for both normal and
424 partial matching. If you want to restrict the JIT compiling modes, you can
425 follow \fB/S+\fP with a digit in the range 1 to 7:
426 .sp
427 1 normal match only
428 2 soft partial match only
429 3 normal match and soft partial match
430 4 hard partial match only
431 6 soft and hard partial match
432 7 all three modes (default)
433 .sp
434 If \fB/S++\fP is used instead of \fB/S+\fP (with or without a following digit),
435 the text "(JIT)" is added to the first output line after a match or no match
436 when JIT-compiled code was actually used.
437 .P
438 Note that there is also an independent \fB/+\fP modifier; it must not be given
439 immediately after \fB/S\fP or \fB/S+\fP because this will be misinterpreted.
440 .P
441 If JIT studying is successful, the compiled JIT code will automatically be used
442 when \fBpcre[16]_exec()\fP is run, except when incompatible run-time options
443 are specified. For more details, see the
444 .\" HREF
445 \fBpcrejit\fP
446 .\"
447 documentation. See also the \fB\eJ\fP escape sequence below for a way of
448 setting the size of the JIT stack.
449 .P
450 Finally, if \fB/S\fP is followed by a minus character, JIT compilation is
451 suppressed, even if it was requested externally by the \fB-s\fP command line
452 option. This makes it possible to specify that JIT is never to be used for
453 certain patterns.
454 .P
455 The \fB/T\fP modifier must be followed by a single digit. It causes a specific
456 set of built-in character tables to be passed to \fBpcre[16]_compile()\fP. It
457 is used in the standard PCRE tests to check behaviour with different character
458 tables. The digit specifies the tables as follows:
459 .sp
460 0 the default ASCII tables, as distributed in
461 pcre_chartables.c.dist
462 1 a set of tables defining ISO 8859 characters
463 .sp
464 In table 1, some characters whose codes are greater than 128 are identified as
465 letters, digits, spaces, etc.
466 .
467 .
468 .SS "Using the POSIX wrapper API"
469 .rs
470 .sp
471 The \fB/P\fP modifier causes \fBpcretest\fP to call PCRE via the POSIX wrapper
472 API rather than its native API. This supports only the 8-bit library. When
473 \fB/P\fP is set, the following modifiers set options for the \fBregcomp()\fP
474 function:
475 .sp
476 /i REG_ICASE
479 /s REG_DOTALL )
480 /U REG_UNGREEDY ) These options are not part of
481 /W REG_UCP ) the POSIX standard
482 /8 REG_UTF8 )
483 .sp
484 The \fB/+\fP modifier works as described above. All other modifiers are
485 ignored.
486 .
487 .
489 .rs
490 .sp
491 Before each data line is passed to \fBpcre[16]_exec()\fP, leading and trailing
492 white space is removed, and it is then scanned for \e escapes. Some of these
493 are pretty esoteric features, intended for checking out some of the more
494 complicated features of PCRE. If you are just testing "ordinary" regular
495 expressions, you probably don't need any of these. The following escapes are
496 recognized:
497 .sp
498 \ea alarm (BEL, \ex07)
499 \eb backspace (\ex08)
500 \ee escape (\ex27)
501 \ef form feed (\ex0c)
502 \en newline (\ex0a)
503 .\" JOIN
504 \eqdd set the PCRE_MATCH_LIMIT limit to dd
505 (any number of digits)
506 \er carriage return (\ex0d)
507 \et tab (\ex09)
508 \ev vertical tab (\ex0b)
509 \ennn octal character (up to 3 octal digits); always
510 a byte unless > 255 in UTF-8 or 16-bit mode
511 \exhh hexadecimal byte (up to 2 hex digits)
512 \ex{hh...} hexadecimal character (any number of hex digits)
513 .\" JOIN
514 \eA pass the PCRE_ANCHORED option to \fBpcre[16]_exec()\fP
515 or \fBpcre[16]_dfa_exec()\fP
516 .\" JOIN
517 \eB pass the PCRE_NOTBOL option to \fBpcre[16]_exec()\fP
518 or \fBpcre[16]_dfa_exec()\fP
519 .\" JOIN
520 \eCdd call pcre[16]_copy_substring() for substring dd
521 after a successful match (number less than 32)
522 .\" JOIN
523 \eCname call pcre[16]_copy_named_substring() for substring
524 "name" after a successful match (name termin-
525 ated by next non alphanumeric character)
526 .\" JOIN
527 \eC+ show the current captured substrings at callout
528 time
529 \eC- do not supply a callout function
530 .\" JOIN
531 \eC!n return 1 instead of 0 when callout number n is
532 reached
533 .\" JOIN
534 \eC!n!m return 1 instead of 0 when callout number n is
535 reached for the nth time
536 .\" JOIN
537 \eC*n pass the number n (may be negative) as callout
538 data; this is used as the callout return value
539 \eD use the \fBpcre[16]_dfa_exec()\fP match function
540 \eF only shortest match for \fBpcre[16]_dfa_exec()\fP
541 .\" JOIN
542 \eGdd call pcre[16]_get_substring() for substring dd
543 after a successful match (number less than 32)
544 .\" JOIN
545 \eGname call pcre[16]_get_named_substring() for substring
546 "name" after a successful match (name termin-
547 ated by next non-alphanumeric character)
548 .\" JOIN
549 \eJdd set up a JIT stack of dd kilobytes maximum (any
550 number of digits)
551 .\" JOIN
552 \eL call pcre[16]_get_substringlist() after a
553 successful match
554 .\" JOIN
555 \eM discover the minimum MATCH_LIMIT and
557 .\" JOIN
558 \eN pass the PCRE_NOTEMPTY option to \fBpcre[16]_exec()\fP
559 or \fBpcre[16]_dfa_exec()\fP; if used twice, pass the
561 .\" JOIN
562 \eOdd set the size of the output vector passed to
563 \fBpcre[16]_exec()\fP to dd (any number of digits)
564 .\" JOIN
565 \eP pass the PCRE_PARTIAL_SOFT option to \fBpcre[16]_exec()\fP
566 or \fBpcre[16]_dfa_exec()\fP; if used twice, pass the
568 .\" JOIN
569 \eQdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
570 (any number of digits)
571 \eR pass the PCRE_DFA_RESTART option to \fBpcre[16]_dfa_exec()\fP
572 \eS output details of memory get/free calls during matching
573 .\" JOIN
574 \eY pass the PCRE_NO_START_OPTIMIZE option to \fBpcre[16]_exec()\fP
575 or \fBpcre[16]_dfa_exec()\fP
576 .\" JOIN
577 \eZ pass the PCRE_NOTEOL option to \fBpcre[16]_exec()\fP
578 or \fBpcre[16]_dfa_exec()\fP
579 .\" JOIN
580 \e? pass the PCRE_NO_UTF[8|16]_CHECK option to
581 \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP
582 .\" JOIN
583 \e>dd start the match at offset dd (optional "-"; then
584 any number of digits); this sets the \fIstartoffset\fP
585 argument for \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP
586 .\" JOIN
587 \e<cr> pass the PCRE_NEWLINE_CR option to \fBpcre[16]_exec()\fP
588 or \fBpcre[16]_dfa_exec()\fP
589 .\" JOIN
590 \e<lf> pass the PCRE_NEWLINE_LF option to \fBpcre[16]_exec()\fP
591 or \fBpcre[16]_dfa_exec()\fP
592 .\" JOIN
593 \e<crlf> pass the PCRE_NEWLINE_CRLF option to \fBpcre[16]_exec()\fP
594 or \fBpcre[16]_dfa_exec()\fP
595 .\" JOIN
596 \e<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to \fBpcre[16]_exec()\fP
597 or \fBpcre[16]_dfa_exec()\fP
598 .\" JOIN
599 \e<any> pass the PCRE_NEWLINE_ANY option to \fBpcre[16]_exec()\fP
600 or \fBpcre[16]_dfa_exec()\fP
601 .sp
602 The use of \ex{hh...} is not dependent on the use of the \fB/8\fP modifier on
603 the pattern. It is recognized always. There may be any number of hexadecimal
604 digits inside the braces; invalid values provoke error messages.
605 .P
606 Note that \exhh specifies one byte rather than one character in UTF-8 mode;
607 this makes it possible to construct invalid UTF-8 sequences for testing
608 purposes. On the other hand, \ex{hh} is interpreted as a UTF-8 character in
609 UTF-8 mode, generating more than one byte if the value is greater than 127.
610 When testing the 8-bit library not in UTF-8 mode, \ex{hh} generates one byte
611 for values less than 256, and causes an error for greater values.
612 .P
613 In UTF-16 mode, all 4-digit \ex{hhhh} values are accepted. This makes it
614 possible to construct invalid UTF-16 sequences for testing purposes.
615 .P
616 The escapes that specify line ending sequences are literal strings, exactly as
617 shown. No more than one newline setting should be present in any data line.
618 .P
619 A backslash followed by anything else just escapes the anything else. If
620 the very last character is a backslash, it is ignored. This gives a way of
621 passing an empty line as data, since a real empty line terminates the data
622 input.
623 .P
624 The \fB\eJ\fP escape provides a way of setting the maximum stack size that is
625 used by the just-in-time optimization code. It is ignored if JIT optimization
626 is not being used. Providing a stack that is larger than the default 32K is
627 necessary only for very complicated patterns.
628 .P
629 If \eM is present, \fBpcretest\fP calls \fBpcre[16]_exec()\fP several times,
630 with different values in the \fImatch_limit\fP and \fImatch_limit_recursion\fP
631 fields of the \fBpcre[16]_extra\fP data structure, until it finds the minimum
632 numbers for each parameter that allow \fBpcre[16]_exec()\fP to complete without
633 error. Because this is testing a specific feature of the normal interpretive
634 \fBpcre[16]_exec()\fP execution, the use of any JIT optimization that might
635 have been set up by the \fB/S+\fP qualifier of \fB-s+\fP option is disabled.
636 .P
637 The \fImatch_limit\fP number is a measure of the amount of backtracking
638 that takes place, and checking it out can be instructive. For most simple
639 matches, the number is quite small, but for patterns with very large numbers of
640 matching possibilities, it can become large very quickly with increasing length
641 of subject string. The \fImatch_limit_recursion\fP number is a measure of how
642 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is
643 needed to complete the match attempt.
644 .P
645 When \eO is used, the value specified may be higher or lower than the size set
646 by the \fB-O\fP command line option (or defaulted to 45); \eO applies only to
647 the call of \fBpcre[16]_exec()\fP for the line in which it appears.
648 .P
649 If the \fB/P\fP modifier was present on the pattern, causing the POSIX wrapper
650 API to be used, the only option-setting sequences that have any effect are \eB,
651 \eN, and \eZ, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,
652 to be passed to \fBregexec()\fP.
653 .
654 .
656 .rs
657 .sp
658 By default, \fBpcretest\fP uses the standard PCRE matching function,
659 \fBpcre[16]_exec()\fP to match each data line. PCRE also supports an
660 alternative matching function, \fBpcre[16]_dfa_test()\fP, which operates in a
661 different way, and has some restrictions. The differences between the two
662 functions are described in the
663 .\" HREF
664 \fBpcrematching\fP
665 .\"
666 documentation.
667 .P
668 If a data line contains the \eD escape sequence, or if the command line
669 contains the \fB-dfa\fP option, the alternative matching function is used.
670 This function finds all possible matches at a given point. If, however, the \eF
671 escape sequence is present in the data line, it stops after the first match is
672 found. This is always the shortest possible match.
673 .
674 .
676 .rs
677 .sp
678 This section describes the output when the normal matching function,
679 \fBpcre[16]_exec()\fP, is being used.
680 .P
681 When a match succeeds, \fBpcretest\fP outputs the list of captured substrings
682 that \fBpcre[16]_exec()\fP returns, starting with number 0 for the string that
683 matched the whole pattern. Otherwise, it outputs "No match" when the return is
684 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
685 substring when \fBpcre[16]_exec()\fP returns PCRE_ERROR_PARTIAL. (Note that
686 this is the entire substring that was inspected during the partial match; it
687 may include characters before the actual match start if a lookbehind assertion,
688 \eK, \eb, or \eB was involved.) For any other return, \fBpcretest\fP outputs
689 the PCRE negative error number and a short descriptive phrase. If the error is
690 a failed UTF string check, the offset of the start of the failing character and
691 the reason code are also output, provided that the size of the output vector is
692 at least two. Here is an example of an interactive \fBpcretest\fP run.
693 .sp
694 $ pcretest
695 PCRE version 8.13 2011-04-30
696 .sp
697 re> /^abc(\ed+)/
698 data> abc123
699 0: abc123
700 1: 123
701 data> xyz
702 No match
703 .sp
704 Unset capturing substrings that are not followed by one that is set are not
705 returned by \fBpcre[16]_exec()\fP, and are not shown by \fBpcretest\fP. In the
706 following example, there are two capturing substrings, but when the first data
707 line is matched, the second, unset substring is not shown. An "internal" unset
708 substring is shown as "<unset>", as for the second data line.
709 .sp
710 re> /(a)|(b)/
711 data> a
712 0: a
713 1: a
714 data> b
715 0: b
716 1: <unset>
717 2: b
718 .sp
719 If the strings contain any non-printing characters, they are output as \exhh
720 escapes if the value is less than 256 and UTF mode is not set. Otherwise they
721 are output as \ex{hh...} escapes. See below for the definition of non-printing
722 characters. If the pattern has the \fB/+\fP modifier, the output for substring
723 0 is followed by the the rest of the subject string, identified by "0+" like
724 this:
725 .sp
726 re> /cat/+
727 data> cataract
728 0: cat
729 0+ aract
730 .sp
731 If the pattern has the \fB/g\fP or \fB/G\fP modifier, the results of successive
732 matching attempts are output in sequence, like this:
733 .sp
734 re> /\eBi(\ew\ew)/g
735 data> Mississippi
736 0: iss
737 1: ss
738 0: iss
739 1: ss
740 0: ipp
741 1: pp
742 .sp
743 "No match" is output only if the first match attempt fails. Here is an example
744 of a failure message (the offset 4 that is specified by \e>4 is past the end of
745 the subject string):
746 .sp
747 re> /xyz/
748 data> xyz\e>4
749 Error -24 (bad offset value)
750 .P
751 If any of the sequences \fB\eC\fP, \fB\eG\fP, or \fB\eL\fP are present in a
752 data line that is successfully matched, the substrings extracted by the
753 convenience functions are output with C, G, or L after the string number
754 instead of a colon. This is in addition to the normal full list. The string
755 length (that is, the return from the extraction function) is given in
756 parentheses after each string for \fB\eC\fP and \fB\eG\fP.
757 .P
758 Note that whereas patterns can be continued over several lines (a plain ">"
759 prompt is used for continuations), data lines may not. However newlines can be
760 included in data by means of the \en escape (or \er, \er\en, etc., depending on
761 the newline sequence setting).
762 .
763 .
764 .
766 .rs
767 .sp
768 When the alternative matching function, \fBpcre[16]_dfa_exec()\fP, is used (by
769 means of the \eD escape sequence or the \fB-dfa\fP command line option), the
770 output consists of a list of all the matches that start at the first point in
771 the subject where there is at least one match. For example:
772 .sp
773 re> /(tang|tangerine|tan)/
774 data> yellow tangerine\eD
775 0: tangerine
776 1: tang
777 2: tan
778 .sp
779 (Using the normal matching function on this data finds only "tang".) The
780 longest matching string is always given first (and numbered zero). After a
781 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
782 partially matching substring. (Note that this is the entire substring that was
783 inspected during the partial match; it may include characters before the actual
784 match start if a lookbehind assertion, \eK, \eb, or \eB was involved.)
785 .P
786 If \fB/g\fP is present on the pattern, the search for further matches resumes
787 at the end of the longest match. For example:
788 .sp
789 re> /(tang|tangerine|tan)/g
790 data> yellow tangerine and tangy sultana\eD
791 0: tangerine
792 1: tang
793 2: tan
794 0: tang
795 1: tan
796 0: tan
797 .sp
798 Since the matching function does not support substring capture, the escape
799 sequences that are concerned with captured substrings are not relevant.
800 .
801 .
803 .rs
804 .sp
805 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
806 indicating that the subject partially matched the pattern, you can restart the
807 match with additional subject data by means of the \eR escape sequence. For
808 example:
809 .sp
810 re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/
811 data> 23ja\eP\eD
812 Partial match: 23ja
813 data> n05\eR\eD
814 0: n05
815 .sp
816 For further information about partial matching, see the
817 .\" HREF
818 \fBpcrepartial\fP
819 .\"
820 documentation.
821 .
822 .
824 .rs
825 .sp
826 If the pattern contains any callout requests, \fBpcretest\fP's callout function
827 is called during matching. This works with both matching functions. By default,
828 the called function displays the callout number, the start and current
829 positions in the text at the callout time, and the next pattern item to be
830 tested. For example:
831 .sp
832 --->pqrabcdef
833 0 ^ ^ \ed
834 .sp
835 This output indicates that callout number 0 occurred for a match attempt
836 starting at the fourth character of the subject string, when the pointer was at
837 the seventh character of the data, and when the next pattern item was \ed. Just
838 one circumflex is output if the start and current positions are the same.
839 .P
840 Callouts numbered 255 are assumed to be automatic callouts, inserted as a
841 result of the \fB/C\fP pattern modifier. In this case, instead of showing the
842 callout number, the offset in the pattern, preceded by a plus, is output. For
843 example:
844 .sp
845 re> /\ed?[A-E]\e*/C
846 data> E*
847 --->E*
848 +0 ^ \ed?
849 +3 ^ [A-E]
850 +8 ^^ \e*
851 +10 ^ ^
852 0: E*
853 .sp
854 If a pattern contains (*MARK) items, an additional line is output whenever
855 a change of latest mark is passed to the callout function. For example:
856 .sp
857 re> /a(*MARK:X)bc/C
858 data> abc
859 --->abc
860 +0 ^ a
861 +1 ^^ (*MARK:X)
862 +10 ^^ b
863 Latest Mark: X
864 +11 ^ ^ c
865 +12 ^ ^
866 0: abc
867 .sp
868 The mark changes between matching "a" and "b", but stays the same for the rest
869 of the match, so nothing more is output. If, as a result of backtracking, the
870 mark reverts to being unset, the text "<unset>" is output.
871 .P
872 The callout function in \fBpcretest\fP returns zero (carry on matching) by
873 default, but you can use a \eC item in a data line (as described above) to
874 change this and other parameters of the callout.
875 .P
876 Inserting callouts can be helpful when using \fBpcretest\fP to check
877 complicated regular expressions. For further information about callouts, see
878 the
879 .\" HREF
880 \fBpcrecallout\fP
881 .\"
882 documentation.
883 .
884 .
885 .
887 .rs
888 .sp
889 When \fBpcretest\fP is outputting text in the compiled version of a pattern,
890 bytes other than 32-126 are always treated as non-printing characters are are
891 therefore shown as hex escapes.
892 .P
893 When \fBpcretest\fP is outputting text that is a matched part of a subject
894 string, it behaves in the same way, unless a different locale has been set for
895 the pattern (using the \fB/L\fP modifier). In this case, the \fBisprint()\fP
896 function to distinguish printing and non-printing characters.
897 .
898 .
899 .
901 .rs
902 .sp
903 The facilities described in this section are not available when the POSIX
904 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
905 specified.
906 .P
907 When the POSIX interface is not in use, you can cause \fBpcretest\fP to write a
908 compiled pattern to a file, by following the modifiers with > and a file name.
909 For example:
910 .sp
911 /pattern/im >/some/file
912 .sp
913 See the
914 .\" HREF
915 \fBpcreprecompile\fP
916 .\"
917 documentation for a discussion about saving and re-using compiled patterns.
918 Note that if the pattern was successfully studied with JIT optimization, the
919 JIT data cannot be saved.
920 .P
921 The data that is written is binary. The first eight bytes are the length of the
922 compiled pattern data followed by the length of the optional study data, each
923 written as four bytes in big-endian order (most significant byte first). If
924 there is no study data (either the pattern was not studied, or studying did not
925 return any data), the second length is zero. The lengths are followed by an
926 exact copy of the compiled pattern. If there is additional study data, this
927 (excluding any JIT data) follows immediately after the compiled pattern. After
928 writing the file, \fBpcretest\fP expects to read a new pattern.
929 .P
930 A saved pattern can be reloaded into \fBpcretest\fP by specifying < and a file
931 name instead of a pattern. The name of the file must not contain a < character,
932 as otherwise \fBpcretest\fP will interpret the line as a pattern delimited by <
933 characters.
934 For example:
935 .sp
936 re> </some/file
937 Compiled pattern loaded from /some/file
938 No study data
939 .sp
940 If the pattern was previously studied with the JIT optimization, the JIT
941 information cannot be saved and restored, and so is lost. When the pattern has
942 been loaded, \fBpcretest\fP proceeds to read data lines in the usual way.
943 .P
944 You can copy a file written by \fBpcretest\fP to a different host and reload it
945 there, even if the new host has opposite endianness to the one on which the
946 pattern was compiled. For example, you can compile on an i86 machine and run on
947 a SPARC machine. When a pattern is reloaded on a host with different
948 endianness, the confirmation message is changed to:
949 .sp
950 Compiled pattern (byte-inverted) loaded from /some/file
951 .sp
952 The test suite contains some saved pre-compiled patterns with different
953 endianness. These are reloaded using "<!" instead of just "<". This suppresses
954 the "(byte-inverted)" text so that the output is the same on all hosts. It also
955 forces debugging output once the pattern has been reloaded.
956 .P
957 File names for saving and reloading can be absolute or relative, but note that
958 the shell facility of expanding a file name that starts with a tilde (~) is not
959 available.
960 .P
961 The ability to save and reload files in \fBpcretest\fP is intended for testing
962 and experimentation. It is not intended for production use because only a
963 single pattern can be written to a file. Furthermore, there is no facility for
964 supplying custom character tables for use with a reloaded pattern. If the
965 original pattern was compiled with custom tables, an attempt to match a subject
966 string using a reloaded pattern is likely to cause \fBpcretest\fP to crash.
967 Finally, if you attempt to load a file that is not in the correct format, the
968 result is undefined.
969 .
970 .
971 .SH "SEE ALSO"
972 .rs
973 .sp
974 \fBpcre\fP(3), \fBpcre16\fP(3), \fBpcreapi\fP(3), \fBpcrecallout\fP(3),
975 \fBpcrejit\fP, \fBpcrematching\fP(3), \fBpcrepartial\fP(d),
976 \fBpcrepattern\fP(3), \fBpcreprecompile\fP(3).
977 .
978 .
980 .rs
981 .sp
982 .nf
983 Philip Hazel
984 University Computing Service
985 Cambridge CB2 3QH, England.
986 .fi
987 .
988 .
990 .rs
991 .sp
992 .nf
993 Last updated: 28 August 2012
994 Copyright (c) 1997-2012 University of Cambridge.
995 .fi


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