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1 .TH PCRETEST 1 "10 September 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 ,
22 .\" HREF
23 \fBpcre16\fP
24 and
25 .\" HREF
26 \fBpcre32\fP
27 .\"
28 documentation.
29 .P
30 The input for \fBpcretest\fP is a sequence of regular expression patterns and
31 strings to be matched, as described below. The output shows the result of each
32 match. Options on the command line and the patterns control PCRE options and
33 exactly what is output.
34 .P
35 As PCRE has evolved, it has acquired many different features, and as a result,
36 \fBpcretest\fP now has rather a lot of obscure options for testing every
37 possible feature. Some of these options are specifically designed for use in
38 conjunction with the test script and data files that are distributed as part of
39 PCRE, and are unlikely to be of use otherwise. They are all documented here,
40 but without much justification.
41 .
42 .
44 .rs
45 .sp
46 From release 8.30, two separate PCRE libraries can be built. The original one
47 supports 8-bit character strings, whereas the newer 16-bit library supports
48 character strings encoded in 16-bit units. From release 8.32, a third
49 library can be built, supporting character strings encoded in 32-bit units.
50 The \fBpcretest\fP program can be
51 used to test all three libraries. However, it is itself still an 8-bit program,
52 reading 8-bit input and writing 8-bit output. When testing the 16-bit or 32-bit
53 library, the patterns and data strings are converted to 16- or 32-bit format
54 before being passed to the PCRE library functions. Results are converted to
55 8-bit for output.
56 .P
57 References to functions and structures of the form \fBpcre[16|32]_xx\fP below
58 mean "\fBpcre_xx\fP when using the 8-bit library or \fBpcre16_xx\fP when using
59 the 16-bit library".
60 .
61 .
63 .rs
64 .TP 10
65 \fB-8\fP
66 If both the 8-bit library has been built, this option causes the 8-bit library
67 to be used (which is the default); if the 8-bit library has not been built,
68 this option causes an error.
69 .TP 10
70 \fB-16\fP
71 If both the 8-bit or the 32-bit, and the 16-bit libraries have been built, this
72 option causes the 16-bit library to be used. If only the 16-bit library has been
73 built, this is the default (so has no effect). If only the 8-bit or the 32-bit
74 library has been built, this option causes an error.
75 .TP 10
76 \fB-32\fP
77 If both the 8-bit or the 16-bit, and the 32-bit libraries have been built, this
78 option causes the 32-bit library to be used. If only the 32-bit library has been
79 built, this is the default (so has no effect). If only the 8-bit or the 16-bit
80 library has been built, this option causes an error.
81 .TP 10
82 \fB-b\fP
83 Behave as if each pattern has the \fB/B\fP (show byte code) modifier; the
84 internal form is output after compilation.
85 .TP 10
86 \fB-C\fP
87 Output the version number of the PCRE library, and all available information
88 about the optional features that are included, and then exit. All other options
89 are ignored.
90 .TP 10
91 \fB-C\fP \fIoption\fP
92 Output information about a specific build-time option, then exit. This
93 functionality is intended for use in scripts such as \fBRunTest\fP. The
94 following options output the value indicated:
95 .sp
96 ebcdic-nl the code for LF (= NL) in an EBCDIC environment:
97 0x15 or 0x25
98 0 if used in an ASCII environment
99 linksize the internal link size (2, 3, or 4)
100 newline the default newline setting:
102 .sp
103 The following options output 1 for true or zero for false:
104 .sp
105 ebcdic compiled for an EBCDIC environment
106 jit just-in-time support is available
107 pcre16 the 16-bit library was built
108 pcre32 the 32-bit library was built
109 pcre8 the 8-bit library was built
110 ucp Unicode property support is available
111 utf UTF-8 and/or UTF-16 and/or UTF-32 support is available
112 .TP 10
113 \fB-d\fP
114 Behave as if each pattern has the \fB/D\fP (debug) modifier; the internal
115 form and information about the compiled pattern is output after compilation;
116 \fB-d\fP is equivalent to \fB-b -i\fP.
117 .TP 10
118 \fB-dfa\fP
119 Behave as if each data line contains the \eD escape sequence; this causes the
120 alternative matching function, \fBpcre[16|32]_dfa_exec()\fP, to be used instead
121 of the standard \fBpcre[16|32]_exec()\fP function (more detail is given below).
122 .TP 10
123 \fB-help\fP
124 Output a brief summary these options and then exit.
125 .TP 10
126 \fB-i\fP
127 Behave as if each pattern has the \fB/I\fP modifier; information about the
128 compiled pattern is given after compilation.
129 .TP 10
130 \fB-M\fP
131 Behave as if each data line contains the \eM escape sequence; this causes
132 PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by
133 calling \fBpcre[16|32]_exec()\fP repeatedly with different limits.
134 .TP 10
135 \fB-m\fP
136 Output the size of each compiled pattern after it has been compiled. This is
137 equivalent to adding \fB/M\fP to each regular expression. The size is given in
138 bytes for both libraries.
139 .TP 10
140 \fB-o\fP \fIosize\fP
141 Set the number of elements in the output vector that is used when calling
142 \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP to be \fIosize\fP. The
143 default value is 45, which is enough for 14 capturing subexpressions for
144 \fBpcre[16|32]_exec()\fP or 22 different matches for
145 \fBpcre[16|32]_dfa_exec()\fP.
146 The vector size can be changed for individual matching calls by including \eO
147 in the data line (see below).
148 .TP 10
149 \fB-p\fP
150 Behave as if each pattern has the \fB/P\fP modifier; the POSIX wrapper API is
151 used to call PCRE. None of the other options has any effect when \fB-p\fP is
152 set. This option can be used only with the 8-bit library.
153 .TP 10
154 \fB-q\fP
155 Do not output the version number of \fBpcretest\fP at the start of execution.
156 .TP 10
157 \fB-S\fP \fIsize\fP
158 On Unix-like systems, set the size of the run-time stack to \fIsize\fP
159 megabytes.
160 .TP 10
161 \fB-s\fP or \fB-s+\fP
162 Behave as if each pattern has the \fB/S\fP modifier; in other words, force each
163 pattern to be studied. If \fB-s+\fP is used, all the JIT compile options are
164 passed to \fBpcre[16|32]_study()\fP, causing just-in-time optimization to be set
165 up if it is available, for both full and partial matching. Specific JIT compile
166 options can be selected by following \fB-s+\fP with a digit in the range 1 to
167 7, which selects the JIT compile modes as follows:
168 .sp
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 .sp
176 If \fB-s++\fP is used instead of \fB-s+\fP (with or without a following digit),
177 the text "(JIT)" is added to the first output line after a match or no match
178 when JIT-compiled code was actually used.
179 .sp
180 Note that there are pattern options that can override \fB-s\fP, either
181 specifying no studying at all, or suppressing JIT compilation.
182 .sp
183 If the \fB/I\fP or \fB/D\fP option is present on a pattern (requesting output
184 about the compiled pattern), information about the result of studying is not
185 included when studying is caused only by \fB-s\fP and neither \fB-i\fP nor
186 \fB-d\fP is present on the command line. This behaviour means that the output
187 from tests that are run with and without \fB-s\fP should be identical, except
188 when options that output information about the actual running of a match are
189 set.
190 .sp
191 The \fB-M\fP, \fB-t\fP, and \fB-tm\fP options, which give information about
192 resources used, are likely to produce different output with and without
193 \fB-s\fP. Output may also differ if the \fB/C\fP option is present on an
194 individual pattern. This uses callouts to trace the the matching process, and
195 this may be different between studied and non-studied patterns. If the pattern
196 contains (*MARK) items there may also be differences, for the same reason. The
197 \fB-s\fP command line option can be overridden for specific patterns that
198 should never be studied (see the \fB/S\fP pattern modifier below).
199 .TP 10
200 \fB-t\fP
201 Run each compile, study, and match many times with a timer, and output
202 resulting time per compile or match (in milliseconds). Do not set \fB-m\fP with
203 \fB-t\fP, because you will then get the size output a zillion times, and the
204 timing will be distorted. You can control the number of iterations that are
205 used for timing by following \fB-t\fP with a number (as a separate item on the
206 command line). For example, "-t 1000" would iterate 1000 times. The default is
207 to iterate 500000 times.
208 .TP 10
209 \fB-tm\fP
210 This is like \fB-t\fP except that it times only the matching phase, not the
211 compile or study phases.
212 .
213 .
215 .rs
216 .sp
217 If \fBpcretest\fP is given two filename arguments, it reads from the first and
218 writes to the second. If it is given only one filename argument, it reads from
219 that file and writes to stdout. Otherwise, it reads from stdin and writes to
220 stdout, and prompts for each line of input, using "re>" to prompt for regular
221 expressions, and "data>" to prompt for data lines.
222 .P
223 When \fBpcretest\fP is built, a configuration option can specify that it should
224 be linked with the \fBlibreadline\fP library. When this is done, if the input
225 is from a terminal, it is read using the \fBreadline()\fP function. This
226 provides line-editing and history facilities. The output from the \fB-help\fP
227 option states whether or not \fBreadline()\fP will be used.
228 .P
229 The program handles any number of sets of input on a single input file. Each
230 set starts with a regular expression, and continues with any number of data
231 lines to be matched against the pattern.
232 .P
233 Each data line is matched separately and independently. If you want to do
234 multi-line matches, you have to use the \en escape sequence (or \er or \er\en,
235 etc., depending on the newline setting) in a single line of input to encode the
236 newline sequences. There is no limit on the length of data lines; the input
237 buffer is automatically extended if it is too small.
238 .P
239 An empty line signals the end of the data lines, at which point a new regular
240 expression is read. The regular expressions are given enclosed in any
241 non-alphanumeric delimiters other than backslash, for example:
242 .sp
243 /(a|bc)x+yz/
244 .sp
245 White space before the initial delimiter is ignored. A regular expression may
246 be continued over several input lines, in which case the newline characters are
247 included within it. It is possible to include the delimiter within the pattern
248 by escaping it, for example
249 .sp
250 /abc\e/def/
251 .sp
252 If you do so, the escape and the delimiter form part of the pattern, but since
253 delimiters are always non-alphanumeric, this does not affect its interpretation.
254 If the terminating delimiter is immediately followed by a backslash, for
255 example,
256 .sp
257 /abc/\e
258 .sp
259 then a backslash is added to the end of the pattern. This is done to provide a
260 way of testing the error condition that arises if a pattern finishes with a
261 backslash, because
262 .sp
263 /abc\e/
264 .sp
265 is interpreted as the first line of a pattern that starts with "abc/", causing
266 pcretest to read the next line as a continuation of the regular expression.
267 .
268 .
270 .rs
271 .sp
272 A pattern may be followed by any number of modifiers, which are mostly single
273 characters, though some of these can be qualified by further characters.
274 Following Perl usage, these are referred to below as, for example, "the
275 \fB/i\fP modifier", even though the delimiter of the pattern need not always be
276 a slash, and no slash is used when writing modifiers. White space may appear
277 between the final pattern delimiter and the first modifier, and between the
278 modifiers themselves. For reference, here is a complete list of modifiers. They
279 fall into several groups that are described in detail in the following
280 sections.
281 .sp
282 \fB/8\fP set UTF mode
283 \fB/?\fP disable UTF validity check
284 \fB/+\fP show remainder of subject after match
285 \fB/=\fP show all captures (not just those that are set)
286 .sp
287 \fB/A\fP set PCRE_ANCHORED
288 \fB/B\fP show compiled code
290 \fB/D\fP same as \fB/B\fP plus \fB/I\fP
292 \fB/F\fP flip byte order in compiled pattern
293 \fB/f\fP set PCRE_FIRSTLINE
294 \fB/G\fP find all matches (shorten string)
295 \fB/g\fP find all matches (use startoffset)
296 \fB/I\fP show information about pattern
297 \fB/i\fP set PCRE_CASELESS
298 \fB/J\fP set PCRE_DUPNAMES
299 \fB/K\fP show backtracking control names
300 \fB/L\fP set locale
301 \fB/M\fP show compiled memory size
302 \fB/m\fP set PCRE_MULTILINE
304 \fB/P\fP use the POSIX wrapper
305 \fB/S\fP study the pattern after compilation
306 \fB/s\fP set PCRE_DOTALL
307 \fB/T\fP select character tables
308 \fB/U\fP set PCRE_UNGREEDY
309 \fB/W\fP set PCRE_UCP
310 \fB/X\fP set PCRE_EXTRA
311 \fB/x\fP set PCRE_EXTENDED
313 \fB/Z\fP don't show lengths in \fB/B\fP output
314 .sp
315 \fB/<any>\fP set PCRE_NEWLINE_ANY
316 \fB/<anycrlf>\fP set PCRE_NEWLINE_ANYCRLF
317 \fB/<cr>\fP set PCRE_NEWLINE_CR
318 \fB/<crlf>\fP set PCRE_NEWLINE_CRLF
319 \fB/<lf>\fP set PCRE_NEWLINE_LF
320 \fB/<bsr_anycrlf>\fP set PCRE_BSR_ANYCRLF
321 \fB/<bsr_unicode>\fP set PCRE_BSR_UNICODE
323 .sp
324 .
325 .
326 .SS "Perl-compatible modifiers"
327 .rs
328 .sp
329 The \fB/i\fP, \fB/m\fP, \fB/s\fP, and \fB/x\fP modifiers set the PCRE_CASELESS,
330 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
331 \fBpcre[16|32]_compile()\fP is called. These four modifier letters have the same
332 effect as they do in Perl. For example:
333 .sp
334 /caseless/i
335 .sp
336 .
337 .
338 .SS "Modifiers for other PCRE options"
339 .rs
340 .sp
341 The following table shows additional modifiers for setting PCRE compile-time
342 options that do not correspond to anything in Perl:
343 .sp
344 \fB/8\fP PCRE_UTF8 ) when using the 8-bit
345 \fB/?\fP PCRE_NO_UTF8_CHECK ) library
346 .sp
347 \fB/8\fP PCRE_UTF16 ) when using the 16-bit
348 \fB/?\fP PCRE_NO_UTF16_CHECK ) library
349 .sp
350 \fB/8\fP PCRE_UTF32 ) when using the 32-bit
351 \fB/?\fP PCRE_NO_UTF32_CHECK ) library
352 .sp
360 \fB/W\fP PCRE_UCP
363 \fB/<any>\fP PCRE_NEWLINE_ANY
364 \fB/<anycrlf>\fP PCRE_NEWLINE_ANYCRLF
365 \fB/<cr>\fP PCRE_NEWLINE_CR
366 \fB/<crlf>\fP PCRE_NEWLINE_CRLF
367 \fB/<lf>\fP PCRE_NEWLINE_LF
368 \fB/<bsr_anycrlf>\fP PCRE_BSR_ANYCRLF
369 \fB/<bsr_unicode>\fP PCRE_BSR_UNICODE
371 .sp
372 The modifiers that are enclosed in angle brackets are literal strings as shown,
373 including the angle brackets, but the letters within can be in either case.
374 This example sets multiline matching with CRLF as the line ending sequence:
375 .sp
376 /^abc/m<CRLF>
377 .sp
378 As well as turning on the PCRE_UTF8/16/32 option, the \fB/8\fP modifier causes
379 all non-printing characters in output strings to be printed using the
380 \ex{hh...} notation. Otherwise, those less than 0x100 are output in hex without
381 the curly brackets.
382 .P
383 Full details of the PCRE options are given in the
384 .\" HREF
385 \fBpcreapi\fP
386 .\"
387 documentation.
388 .
389 .
390 .SS "Finding all matches in a string"
391 .rs
392 .sp
393 Searching for all possible matches within each subject string can be requested
394 by the \fB/g\fP or \fB/G\fP modifier. After finding a match, PCRE is called
395 again to search the remainder of the subject string. The difference between
396 \fB/g\fP and \fB/G\fP is that the former uses the \fIstartoffset\fP argument to
397 \fBpcre[16|32]_exec()\fP to start searching at a new point within the entire
398 string (which is in effect what Perl does), whereas the latter passes over a
399 shortened substring. This makes a difference to the matching process if the
400 pattern begins with a lookbehind assertion (including \eb or \eB).
401 .P
402 If any call to \fBpcre[16|32]_exec()\fP in a \fB/g\fP or \fB/G\fP sequence matches
403 an 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, match at the
405 same point. If this second match fails, the start offset is advanced, and the
406 normal match is retried. This imitates the way Perl handles such cases when
407 using the \fB/g\fP modifier or the \fBsplit()\fP function. Normally, the start
408 offset is advanced by one character, but if the newline convention recognizes
409 CRLF as a newline, and the current character is CR followed by LF, an advance
410 of two is used.
411 .
412 .
413 .SS "Other modifiers"
414 .rs
415 .sp
416 There are yet more modifiers for controlling the way \fBpcretest\fP
417 operates.
418 .P
419 The \fB/+\fP modifier requests that as well as outputting the substring that
420 matched the entire pattern, \fBpcretest\fP should in addition output the
421 remainder of the subject string. This is useful for tests where the subject
422 contains multiple copies of the same substring. If the \fB+\fP modifier appears
423 twice, the same action is taken for captured substrings. In each case the
424 remainder is output on the following line with a plus character following the
425 capture number. Note that this modifier must not immediately follow the /S
426 modifier because /S+ and /S++ have other meanings.
427 .P
428 The \fB/=\fP modifier requests that the values of all potential captured
429 parentheses be output after a match. By default, only those up to the highest
430 one actually used in the match are output (corresponding to the return code
431 from \fBpcre[16|32]_exec()\fP). Values in the offsets vector corresponding to
432 higher numbers should be set to -1, and these are output as "<unset>". This
433 modifier gives a way of checking that this is happening.
434 .P
435 The \fB/B\fP modifier is a debugging feature. It requests that \fBpcretest\fP
436 output a representation of the compiled code after compilation. Normally this
437 information contains length and offset values; however, if \fB/Z\fP is also
438 present, this data is replaced by spaces. This is a special feature for use in
439 the automatic test scripts; it ensures that the same output is generated for
440 different internal link sizes.
441 .P
442 The \fB/D\fP modifier is a PCRE debugging feature, and is equivalent to
443 \fB/BI\fP, that is, both the \fB/B\fP and the \fB/I\fP modifiers.
444 .P
445 The \fB/F\fP modifier causes \fBpcretest\fP to flip the byte order of the
446 2-byte and 4-byte fields in the compiled pattern. This facility is for testing
447 the feature in PCRE that allows it to execute patterns that were compiled on a
448 host with a different endianness. This feature is not available when the POSIX
449 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
450 specified. See also the section about saving and reloading compiled patterns
451 below.
452 .P
453 The \fB/I\fP modifier requests that \fBpcretest\fP output information about the
454 compiled pattern (whether it is anchored, has a fixed first character, and
455 so on). It does this by calling \fBpcre[16|32]_fullinfo()\fP after compiling a
456 pattern. If the pattern is studied, the results of that are also output.
457 .P
458 The \fB/K\fP modifier requests \fBpcretest\fP to show names from backtracking
459 control verbs that are returned from calls to \fBpcre[16|32]_exec()\fP. It causes
460 \fBpcretest\fP to create a \fBpcre[16|32]_extra\fP block if one has not already
461 been created by a call to \fBpcre[16|32]_study()\fP, and to set the
462 PCRE_EXTRA_MARK flag and the \fBmark\fP field within it, every time that
463 \fBpcre[16|32]_exec()\fP is called. If the variable that the \fBmark\fP field
464 points to is non-NULL for a match, non-match, or partial match, \fBpcretest\fP
465 prints the string to which it points. For a match, this is shown on a line by
466 itself, tagged with "MK:". For a non-match it is added to the message.
467 .P
468 The \fB/L\fP modifier must be followed directly by the name of a locale, for
469 example,
470 .sp
471 /pattern/Lfr_FR
472 .sp
473 For this reason, it must be the last modifier. The given locale is set,
474 \fBpcre[16|32]_maketables()\fP is called to build a set of character tables for
475 the locale, and this is then passed to \fBpcre[16|32]_compile()\fP when compiling
476 the regular expression. Without an \fB/L\fP (or \fB/T\fP) modifier, NULL is
477 passed as the tables pointer; that is, \fB/L\fP applies only to the expression
478 on which it appears.
479 .P
480 The \fB/M\fP modifier causes the size in bytes of the memory block used to hold
481 the compiled pattern to be output. This does not include the size of the
482 \fBpcre[16|32]\fP block; it is just the actual compiled data. If the pattern is
483 successfully studied with the PCRE_STUDY_JIT_COMPILE option, the size of the
484 JIT compiled code is also output.
485 .P
486 The \fB/S\fP modifier causes \fBpcre[16|32]_study()\fP to be called after the
487 expression has been compiled, and the results used when the expression is
488 matched. There are a number of qualifying characters that may follow \fB/S\fP.
489 They may appear in any order.
490 .P
491 If \fBS\fP is followed by an exclamation mark, \fBpcre[16|32]_study()\fP is called
492 with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
493 \fBpcre_extra\fP block, even when studying discovers no useful information.
494 .P
495 If \fB/S\fP is followed by a second S character, it suppresses studying, even
496 if it was requested externally by the \fB-s\fP command line option. This makes
497 it possible to specify that certain patterns are always studied, and others are
498 never studied, independently of \fB-s\fP. This feature is used in the test
499 files in a few cases where the output is different when the pattern is studied.
500 .P
501 If the \fB/S\fP modifier is followed by a + character, the call to
502 \fBpcre[16|32]_study()\fP is made with all the JIT study options, requesting
503 just-in-time optimization support if it is available, for both normal and
504 partial matching. If you want to restrict the JIT compiling modes, you can
505 follow \fB/S+\fP with a digit in the range 1 to 7:
506 .sp
507 1 normal match only
508 2 soft partial match only
509 3 normal match and soft partial match
510 4 hard partial match only
511 6 soft and hard partial match
512 7 all three modes (default)
513 .sp
514 If \fB/S++\fP is used instead of \fB/S+\fP (with or without a following digit),
515 the text "(JIT)" is added to the first output line after a match or no match
516 when JIT-compiled code was actually used.
517 .P
518 Note that there is also an independent \fB/+\fP modifier; it must not be given
519 immediately after \fB/S\fP or \fB/S+\fP because this will be misinterpreted.
520 .P
521 If JIT studying is successful, the compiled JIT code will automatically be used
522 when \fBpcre[16|32]_exec()\fP is run, except when incompatible run-time options
523 are specified. For more details, see the
524 .\" HREF
525 \fBpcrejit\fP
526 .\"
527 documentation. See also the \fB\eJ\fP escape sequence below for a way of
528 setting the size of the JIT stack.
529 .P
530 Finally, if \fB/S\fP is followed by a minus character, JIT compilation is
531 suppressed, even if it was requested externally by the \fB-s\fP command line
532 option. This makes it possible to specify that JIT is never to be used for
533 certain patterns.
534 .P
535 The \fB/T\fP modifier must be followed by a single digit. It causes a specific
536 set of built-in character tables to be passed to \fBpcre[16|32]_compile()\fP. It
537 is used in the standard PCRE tests to check behaviour with different character
538 tables. The digit specifies the tables as follows:
539 .sp
540 0 the default ASCII tables, as distributed in
541 pcre_chartables.c.dist
542 1 a set of tables defining ISO 8859 characters
543 .sp
544 In table 1, some characters whose codes are greater than 128 are identified as
545 letters, digits, spaces, etc.
546 .
547 .
548 .SS "Using the POSIX wrapper API"
549 .rs
550 .sp
551 The \fB/P\fP modifier causes \fBpcretest\fP to call PCRE via the POSIX wrapper
552 API rather than its native API. This supports only the 8-bit library. When
553 \fB/P\fP is set, the following modifiers set options for the \fBregcomp()\fP
554 function:
555 .sp
556 /i REG_ICASE
559 /s REG_DOTALL )
560 /U REG_UNGREEDY ) These options are not part of
561 /W REG_UCP ) the POSIX standard
562 /8 REG_UTF8 )
563 .sp
564 The \fB/+\fP modifier works as described above. All other modifiers are
565 ignored.
566 .
567 .
569 .rs
570 .sp
571 Before each data line is passed to \fBpcre[16|32]_exec()\fP, leading and trailing
572 white space is removed, and it is then scanned for \e escapes. Some of these
573 are pretty esoteric features, intended for checking out some of the more
574 complicated features of PCRE. If you are just testing "ordinary" regular
575 expressions, you probably don't need any of these. The following escapes are
576 recognized:
577 .sp
578 \ea alarm (BEL, \ex07)
579 \eb backspace (\ex08)
580 \ee escape (\ex27)
581 \ef form feed (\ex0c)
582 \en newline (\ex0a)
583 .\" JOIN
584 \eqdd set the PCRE_MATCH_LIMIT limit to dd
585 (any number of digits)
586 \er carriage return (\ex0d)
587 \et tab (\ex09)
588 \ev vertical tab (\ex0b)
589 \ennn octal character (up to 3 octal digits); always
590 a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode
591 \exhh hexadecimal byte (up to 2 hex digits)
592 \ex{hh...} hexadecimal character (any number of hex digits)
593 .\" JOIN
594 \eA pass the PCRE_ANCHORED option to \fBpcre[16|32]_exec()\fP
595 or \fBpcre[16|32]_dfa_exec()\fP
596 .\" JOIN
597 \eB pass the PCRE_NOTBOL option to \fBpcre[16|32]_exec()\fP
598 or \fBpcre[16|32]_dfa_exec()\fP
599 .\" JOIN
600 \eCdd call pcre[16|32]_copy_substring() for substring dd
601 after a successful match (number less than 32)
602 .\" JOIN
603 \eCname call pcre[16|32]_copy_named_substring() for substring
604 "name" after a successful match (name termin-
605 ated by next non alphanumeric character)
606 .\" JOIN
607 \eC+ show the current captured substrings at callout
608 time
609 \eC- do not supply a callout function
610 .\" JOIN
611 \eC!n return 1 instead of 0 when callout number n is
612 reached
613 .\" JOIN
614 \eC!n!m return 1 instead of 0 when callout number n is
615 reached for the nth time
616 .\" JOIN
617 \eC*n pass the number n (may be negative) as callout
618 data; this is used as the callout return value
619 \eD use the \fBpcre[16|32]_dfa_exec()\fP match function
620 \eF only shortest match for \fBpcre[16|32]_dfa_exec()\fP
621 .\" JOIN
622 \eGdd call pcre[16|32]_get_substring() for substring dd
623 after a successful match (number less than 32)
624 .\" JOIN
625 \eGname call pcre[16|32]_get_named_substring() for substring
626 "name" after a successful match (name termin-
627 ated by next non-alphanumeric character)
628 .\" JOIN
629 \eJdd set up a JIT stack of dd kilobytes maximum (any
630 number of digits)
631 .\" JOIN
632 \eL call pcre[16|32]_get_substringlist() after a
633 successful match
634 .\" JOIN
635 \eM discover the minimum MATCH_LIMIT and
637 .\" JOIN
638 \eN pass the PCRE_NOTEMPTY option to \fBpcre[16|32]_exec()\fP
639 or \fBpcre[16|32]_dfa_exec()\fP; if used twice, pass the
641 .\" JOIN
642 \eOdd set the size of the output vector passed to
643 \fBpcre[16|32]_exec()\fP to dd (any number of digits)
644 .\" JOIN
645 \eP pass the PCRE_PARTIAL_SOFT option to \fBpcre[16|32]_exec()\fP
646 or \fBpcre[16|32]_dfa_exec()\fP; if used twice, pass the
648 .\" JOIN
649 \eQdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
650 (any number of digits)
651 \eR pass the PCRE_DFA_RESTART option to \fBpcre[16|32]_dfa_exec()\fP
652 \eS output details of memory get/free calls during matching
653 .\" JOIN
654 \eY pass the PCRE_NO_START_OPTIMIZE option to \fBpcre[16|32]_exec()\fP
655 or \fBpcre[16|32]_dfa_exec()\fP
656 .\" JOIN
657 \eZ pass the PCRE_NOTEOL option to \fBpcre[16|32]_exec()\fP
658 or \fBpcre[16|32]_dfa_exec()\fP
659 .\" JOIN
660 \e? pass the PCRE_NO_UTF[8|16|32]_CHECK option to
661 \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP
662 .\" JOIN
663 \e>dd start the match at offset dd (optional "-"; then
664 any number of digits); this sets the \fIstartoffset\fP
665 argument for \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP
666 .\" JOIN
667 \e<cr> pass the PCRE_NEWLINE_CR option to \fBpcre[16|32]_exec()\fP
668 or \fBpcre[16|32]_dfa_exec()\fP
669 .\" JOIN
670 \e<lf> pass the PCRE_NEWLINE_LF option to \fBpcre[16|32]_exec()\fP
671 or \fBpcre[16|32]_dfa_exec()\fP
672 .\" JOIN
673 \e<crlf> pass the PCRE_NEWLINE_CRLF option to \fBpcre[16|32]_exec()\fP
674 or \fBpcre[16|32]_dfa_exec()\fP
675 .\" JOIN
676 \e<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to \fBpcre[16|32]_exec()\fP
677 or \fBpcre[16|32]_dfa_exec()\fP
678 .\" JOIN
679 \e<any> pass the PCRE_NEWLINE_ANY option to \fBpcre[16|32]_exec()\fP
680 or \fBpcre[16|32]_dfa_exec()\fP
681 .sp
682 The use of \ex{hh...} is not dependent on the use of the \fB/8\fP modifier on
683 the pattern. It is recognized always. There may be any number of hexadecimal
684 digits inside the braces; invalid values provoke error messages.
685 .P
686 Note that \exhh specifies one byte rather than one character in UTF-8 mode;
687 this makes it possible to construct invalid UTF-8 sequences for testing
688 purposes. On the other hand, \ex{hh} is interpreted as a UTF-8 character in
689 UTF-8 mode, generating more than one byte if the value is greater than 127.
690 When testing the 8-bit library not in UTF-8 mode, \ex{hh} generates one byte
691 for values less than 256, and causes an error for greater values.
692 .P
693 In UTF-16 mode, all 4-digit \ex{hhhh} values are accepted. This makes it
694 possible to construct invalid UTF-16 sequences for testing purposes.
695 .P
696 In UTF-32 mode, all 4- to 8-digit \ex{...} values are accepted. This makes it
697 possible to construct invalid UTF-32 sequences for testing purposes.
698 .P
699 The escapes that specify line ending sequences are literal strings, exactly as
700 shown. No more than one newline setting should be present in any data line.
701 .P
702 A backslash followed by anything else just escapes the anything else. If
703 the very last character is a backslash, it is ignored. This gives a way of
704 passing an empty line as data, since a real empty line terminates the data
705 input.
706 .P
707 The \fB\eJ\fP escape provides a way of setting the maximum stack size that is
708 used by the just-in-time optimization code. It is ignored if JIT optimization
709 is not being used. Providing a stack that is larger than the default 32K is
710 necessary only for very complicated patterns.
711 .P
712 If \eM is present, \fBpcretest\fP calls \fBpcre[16|32]_exec()\fP several times,
713 with different values in the \fImatch_limit\fP and \fImatch_limit_recursion\fP
714 fields of the \fBpcre[16|32]_extra\fP data structure, until it finds the minimum
715 numbers for each parameter that allow \fBpcre[16|32]_exec()\fP to complete without
716 error. Because this is testing a specific feature of the normal interpretive
717 \fBpcre[16|32]_exec()\fP execution, the use of any JIT optimization that might
718 have been set up by the \fB/S+\fP qualifier of \fB-s+\fP option is disabled.
719 .P
720 The \fImatch_limit\fP number is a measure of the amount of backtracking
721 that takes place, and checking it out can be instructive. For most simple
722 matches, the number is quite small, but for patterns with very large numbers of
723 matching possibilities, it can become large very quickly with increasing length
724 of subject string. The \fImatch_limit_recursion\fP number is a measure of how
725 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is
726 needed to complete the match attempt.
727 .P
728 When \eO is used, the value specified may be higher or lower than the size set
729 by the \fB-O\fP command line option (or defaulted to 45); \eO applies only to
730 the call of \fBpcre[16|32]_exec()\fP for the line in which it appears.
731 .P
732 If the \fB/P\fP modifier was present on the pattern, causing the POSIX wrapper
733 API to be used, the only option-setting sequences that have any effect are \eB,
734 \eN, and \eZ, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,
735 to be passed to \fBregexec()\fP.
736 .
737 .
739 .rs
740 .sp
741 By default, \fBpcretest\fP uses the standard PCRE matching function,
742 \fBpcre[16|32]_exec()\fP to match each data line. PCRE also supports an
743 alternative matching function, \fBpcre[16|32]_dfa_test()\fP, which operates in a
744 different way, and has some restrictions. The differences between the two
745 functions are described in the
746 .\" HREF
747 \fBpcrematching\fP
748 .\"
749 documentation.
750 .P
751 If a data line contains the \eD escape sequence, or if the command line
752 contains the \fB-dfa\fP option, the alternative matching function is used.
753 This function finds all possible matches at a given point. If, however, the \eF
754 escape sequence is present in the data line, it stops after the first match is
755 found. This is always the shortest possible match.
756 .
757 .
759 .rs
760 .sp
761 This section describes the output when the normal matching function,
762 \fBpcre[16|32]_exec()\fP, is being used.
763 .P
764 When a match succeeds, \fBpcretest\fP outputs the list of captured substrings
765 that \fBpcre[16|32]_exec()\fP returns, starting with number 0 for the string that
766 matched the whole pattern. Otherwise, it outputs "No match" when the return is
767 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
768 substring when \fBpcre[16|32]_exec()\fP returns PCRE_ERROR_PARTIAL. (Note that
769 this is the entire substring that was inspected during the partial match; it
770 may include characters before the actual match start if a lookbehind assertion,
771 \eK, \eb, or \eB was involved.) For any other return, \fBpcretest\fP outputs
772 the PCRE negative error number and a short descriptive phrase. If the error is
773 a failed UTF string check, the offset of the start of the failing character and
774 the reason code are also output, provided that the size of the output vector is
775 at least two. Here is an example of an interactive \fBpcretest\fP run.
776 .sp
777 $ pcretest
778 PCRE version 8.13 2011-04-30
779 .sp
780 re> /^abc(\ed+)/
781 data> abc123
782 0: abc123
783 1: 123
784 data> xyz
785 No match
786 .sp
787 Unset capturing substrings that are not followed by one that is set are not
788 returned by \fBpcre[16|32]_exec()\fP, and are not shown by \fBpcretest\fP. In the
789 following example, there are two capturing substrings, but when the first data
790 line is matched, the second, unset substring is not shown. An "internal" unset
791 substring is shown as "<unset>", as for the second data line.
792 .sp
793 re> /(a)|(b)/
794 data> a
795 0: a
796 1: a
797 data> b
798 0: b
799 1: <unset>
800 2: b
801 .sp
802 If the strings contain any non-printing characters, they are output as \exhh
803 escapes if the value is less than 256 and UTF mode is not set. Otherwise they
804 are output as \ex{hh...} escapes. See below for the definition of non-printing
805 characters. If the pattern has the \fB/+\fP modifier, the output for substring
806 0 is followed by the the rest of the subject string, identified by "0+" like
807 this:
808 .sp
809 re> /cat/+
810 data> cataract
811 0: cat
812 0+ aract
813 .sp
814 If the pattern has the \fB/g\fP or \fB/G\fP modifier, the results of successive
815 matching attempts are output in sequence, like this:
816 .sp
817 re> /\eBi(\ew\ew)/g
818 data> Mississippi
819 0: iss
820 1: ss
821 0: iss
822 1: ss
823 0: ipp
824 1: pp
825 .sp
826 "No match" is output only if the first match attempt fails. Here is an example
827 of a failure message (the offset 4 that is specified by \e>4 is past the end of
828 the subject string):
829 .sp
830 re> /xyz/
831 data> xyz\e>4
832 Error -24 (bad offset value)
833 .P
834 If any of the sequences \fB\eC\fP, \fB\eG\fP, or \fB\eL\fP are present in a
835 data line that is successfully matched, the substrings extracted by the
836 convenience functions are output with C, G, or L after the string number
837 instead of a colon. This is in addition to the normal full list. The string
838 length (that is, the return from the extraction function) is given in
839 parentheses after each string for \fB\eC\fP and \fB\eG\fP.
840 .P
841 Note that whereas patterns can be continued over several lines (a plain ">"
842 prompt is used for continuations), data lines may not. However newlines can be
843 included in data by means of the \en escape (or \er, \er\en, etc., depending on
844 the newline sequence setting).
845 .
846 .
847 .
849 .rs
850 .sp
851 When the alternative matching function, \fBpcre[16|32]_dfa_exec()\fP, is used (by
852 means of the \eD escape sequence or the \fB-dfa\fP command line option), the
853 output consists of a list of all the matches that start at the first point in
854 the subject where there is at least one match. For example:
855 .sp
856 re> /(tang|tangerine|tan)/
857 data> yellow tangerine\eD
858 0: tangerine
859 1: tang
860 2: tan
861 .sp
862 (Using the normal matching function on this data finds only "tang".) The
863 longest matching string is always given first (and numbered zero). After a
864 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
865 partially matching substring. (Note that this is the entire substring that was
866 inspected during the partial match; it may include characters before the actual
867 match start if a lookbehind assertion, \eK, \eb, or \eB was involved.)
868 .P
869 If \fB/g\fP is present on the pattern, the search for further matches resumes
870 at the end of the longest match. For example:
871 .sp
872 re> /(tang|tangerine|tan)/g
873 data> yellow tangerine and tangy sultana\eD
874 0: tangerine
875 1: tang
876 2: tan
877 0: tang
878 1: tan
879 0: tan
880 .sp
881 Since the matching function does not support substring capture, the escape
882 sequences that are concerned with captured substrings are not relevant.
883 .
884 .
886 .rs
887 .sp
888 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
889 indicating that the subject partially matched the pattern, you can restart the
890 match with additional subject data by means of the \eR escape sequence. For
891 example:
892 .sp
893 re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/
894 data> 23ja\eP\eD
895 Partial match: 23ja
896 data> n05\eR\eD
897 0: n05
898 .sp
899 For further information about partial matching, see the
900 .\" HREF
901 \fBpcrepartial\fP
902 .\"
903 documentation.
904 .
905 .
907 .rs
908 .sp
909 If the pattern contains any callout requests, \fBpcretest\fP's callout function
910 is called during matching. This works with both matching functions. By default,
911 the called function displays the callout number, the start and current
912 positions in the text at the callout time, and the next pattern item to be
913 tested. For example:
914 .sp
915 --->pqrabcdef
916 0 ^ ^ \ed
917 .sp
918 This output indicates that callout number 0 occurred for a match attempt
919 starting at the fourth character of the subject string, when the pointer was at
920 the seventh character of the data, and when the next pattern item was \ed. Just
921 one circumflex is output if the start and current positions are the same.
922 .P
923 Callouts numbered 255 are assumed to be automatic callouts, inserted as a
924 result of the \fB/C\fP pattern modifier. In this case, instead of showing the
925 callout number, the offset in the pattern, preceded by a plus, is output. For
926 example:
927 .sp
928 re> /\ed?[A-E]\e*/C
929 data> E*
930 --->E*
931 +0 ^ \ed?
932 +3 ^ [A-E]
933 +8 ^^ \e*
934 +10 ^ ^
935 0: E*
936 .sp
937 If a pattern contains (*MARK) items, an additional line is output whenever
938 a change of latest mark is passed to the callout function. For example:
939 .sp
940 re> /a(*MARK:X)bc/C
941 data> abc
942 --->abc
943 +0 ^ a
944 +1 ^^ (*MARK:X)
945 +10 ^^ b
946 Latest Mark: X
947 +11 ^ ^ c
948 +12 ^ ^
949 0: abc
950 .sp
951 The mark changes between matching "a" and "b", but stays the same for the rest
952 of the match, so nothing more is output. If, as a result of backtracking, the
953 mark reverts to being unset, the text "<unset>" is output.
954 .P
955 The callout function in \fBpcretest\fP returns zero (carry on matching) by
956 default, but you can use a \eC item in a data line (as described above) to
957 change this and other parameters of the callout.
958 .P
959 Inserting callouts can be helpful when using \fBpcretest\fP to check
960 complicated regular expressions. For further information about callouts, see
961 the
962 .\" HREF
963 \fBpcrecallout\fP
964 .\"
965 documentation.
966 .
967 .
968 .
970 .rs
971 .sp
972 When \fBpcretest\fP is outputting text in the compiled version of a pattern,
973 bytes other than 32-126 are always treated as non-printing characters are are
974 therefore shown as hex escapes.
975 .P
976 When \fBpcretest\fP is outputting text that is a matched part of a subject
977 string, it behaves in the same way, unless a different locale has been set for
978 the pattern (using the \fB/L\fP modifier). In this case, the \fBisprint()\fP
979 function to distinguish printing and non-printing characters.
980 .
981 .
982 .
984 .rs
985 .sp
986 The facilities described in this section are not available when the POSIX
987 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
988 specified.
989 .P
990 When the POSIX interface is not in use, you can cause \fBpcretest\fP to write a
991 compiled pattern to a file, by following the modifiers with > and a file name.
992 For example:
993 .sp
994 /pattern/im >/some/file
995 .sp
996 See the
997 .\" HREF
998 \fBpcreprecompile\fP
999 .\"
1000 documentation for a discussion about saving and re-using compiled patterns.
1001 Note that if the pattern was successfully studied with JIT optimization, the
1002 JIT data cannot be saved.
1003 .P
1004 The data that is written is binary. The first eight bytes are the length of the
1005 compiled pattern data followed by the length of the optional study data, each
1006 written as four bytes in big-endian order (most significant byte first). If
1007 there is no study data (either the pattern was not studied, or studying did not
1008 return any data), the second length is zero. The lengths are followed by an
1009 exact copy of the compiled pattern. If there is additional study data, this
1010 (excluding any JIT data) follows immediately after the compiled pattern. After
1011 writing the file, \fBpcretest\fP expects to read a new pattern.
1012 .P
1013 A saved pattern can be reloaded into \fBpcretest\fP by specifying < and a file
1014 name instead of a pattern. The name of the file must not contain a < character,
1015 as otherwise \fBpcretest\fP will interpret the line as a pattern delimited by <
1016 characters.
1017 For example:
1018 .sp
1019 re> </some/file
1020 Compiled pattern loaded from /some/file
1021 No study data
1022 .sp
1023 If the pattern was previously studied with the JIT optimization, the JIT
1024 information cannot be saved and restored, and so is lost. When the pattern has
1025 been loaded, \fBpcretest\fP proceeds to read data lines in the usual way.
1026 .P
1027 You can copy a file written by \fBpcretest\fP to a different host and reload it
1028 there, even if the new host has opposite endianness to the one on which the
1029 pattern was compiled. For example, you can compile on an i86 machine and run on
1030 a SPARC machine. When a pattern is reloaded on a host with different
1031 endianness, the confirmation message is changed to:
1032 .sp
1033 Compiled pattern (byte-inverted) loaded from /some/file
1034 .sp
1035 The test suite contains some saved pre-compiled patterns with different
1036 endianness. These are reloaded using "<!" instead of just "<". This suppresses
1037 the "(byte-inverted)" text so that the output is the same on all hosts. It also
1038 forces debugging output once the pattern has been reloaded.
1039 .P
1040 File names for saving and reloading can be absolute or relative, but note that
1041 the shell facility of expanding a file name that starts with a tilde (~) is not
1042 available.
1043 .P
1044 The ability to save and reload files in \fBpcretest\fP is intended for testing
1045 and experimentation. It is not intended for production use because only a
1046 single pattern can be written to a file. Furthermore, there is no facility for
1047 supplying custom character tables for use with a reloaded pattern. If the
1048 original pattern was compiled with custom tables, an attempt to match a subject
1049 string using a reloaded pattern is likely to cause \fBpcretest\fP to crash.
1050 Finally, if you attempt to load a file that is not in the correct format, the
1051 result is undefined.
1052 .
1053 .
1054 .SH "SEE ALSO"
1055 .rs
1056 .sp
1057 \fBpcre\fP(3), \fBpcre16\fP(3), \fBpcre32\fP(3), \fBpcreapi\fP(3),
1058 \fBpcrecallout\fP(3),
1059 \fBpcrejit\fP, \fBpcrematching\fP(3), \fBpcrepartial\fP(d),
1060 \fBpcrepattern\fP(3), \fBpcreprecompile\fP(3).
1061 .
1062 .
1064 .rs
1065 .sp
1066 .nf
1067 Philip Hazel
1068 University Computing Service
1069 Cambridge CB2 3QH, England.
1070 .fi
1071 .
1072 .
1074 .rs
1075 .sp
1076 .nf
1077 Last updated: 10 September 2012
1078 Copyright (c) 1997-2012 University of Cambridge.
1079 .fi


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