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1 nigel 63 <html>
2     <head>
3     <title>pcretest specification</title>
4     </head>
5     <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6 nigel 75 <h1>pcretest man page</h1>
7     <p>
8     Return to the <a href="index.html">PCRE index page</a>.
9     </p>
10 ph10 111 <p>
11 nigel 75 This page is part of the PCRE HTML documentation. It was generated automatically
12     from the original man page. If there is any nonsense in it, please consult the
13     man page, in case the conversion went wrong.
14 ph10 111 <br>
15 nigel 63 <ul>
16     <li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
17     <li><a name="TOC2" href="#SEC2">OPTIONS</a>
18     <li><a name="TOC3" href="#SEC3">DESCRIPTION</a>
19     <li><a name="TOC4" href="#SEC4">PATTERN MODIFIERS</a>
20 nigel 75 <li><a name="TOC5" href="#SEC5">DATA LINES</a>
21 nigel 77 <li><a name="TOC6" href="#SEC6">THE ALTERNATIVE MATCHING FUNCTION</a>
22     <li><a name="TOC7" href="#SEC7">DEFAULT OUTPUT FROM PCRETEST</a>
23     <li><a name="TOC8" href="#SEC8">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a>
24     <li><a name="TOC9" href="#SEC9">RESTARTING AFTER A PARTIAL MATCH</a>
25     <li><a name="TOC10" href="#SEC10">CALLOUTS</a>
26 nigel 93 <li><a name="TOC11" href="#SEC11">NON-PRINTING CHARACTERS</a>
27     <li><a name="TOC12" href="#SEC12">SAVING AND RELOADING COMPILED PATTERNS</a>
28     <li><a name="TOC13" href="#SEC13">SEE ALSO</a>
29     <li><a name="TOC14" href="#SEC14">AUTHOR</a>
30 ph10 99 <li><a name="TOC15" href="#SEC15">REVISION</a>
31 nigel 63 </ul>
32     <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
33     <P>
34 nigel 91 <b>pcretest [options] [source] [destination]</b>
35     <br>
36     <br>
37 nigel 63 <b>pcretest</b> was written as a test program for the PCRE regular expression
38     library itself, but it can also be used for experimenting with regular
39     expressions. This document describes the features of the test program; for
40     details of the regular expressions themselves, see the
41     <a href="pcrepattern.html"><b>pcrepattern</b></a>
42 nigel 75 documentation. For details of the PCRE library function calls and their
43     options, see the
44 nigel 63 <a href="pcreapi.html"><b>pcreapi</b></a>
45     documentation.
46     </P>
47     <br><a name="SEC2" href="#TOC1">OPTIONS</a><br>
48     <P>
49 nigel 93 <b>-b</b>
50     Behave as if each regex has the <b>/B</b> (show bytecode) modifier; the internal
51     form is output after compilation.
52     </P>
53     <P>
54 nigel 63 <b>-C</b>
55     Output the version number of the PCRE library, and all available information
56     about the optional features that are included, and then exit.
57     </P>
58     <P>
59     <b>-d</b>
60 nigel 77 Behave as if each regex has the <b>/D</b> (debug) modifier; the internal
61 nigel 93 form and information about the compiled pattern is output after compilation;
62     <b>-d</b> is equivalent to <b>-b -i</b>.
63 nigel 63 </P>
64     <P>
65 nigel 77 <b>-dfa</b>
66     Behave as if each data line contains the \D escape sequence; this causes the
67     alternative matching function, <b>pcre_dfa_exec()</b>, to be used instead of the
68     standard <b>pcre_exec()</b> function (more detail is given below).
69     </P>
70     <P>
71 nigel 93 <b>-help</b>
72     Output a brief summary these options and then exit.
73     </P>
74     <P>
75 nigel 63 <b>-i</b>
76 nigel 77 Behave as if each regex has the <b>/I</b> modifier; information about the
77 nigel 63 compiled pattern is given after compilation.
78     </P>
79     <P>
80     <b>-m</b>
81     Output the size of each compiled pattern after it has been compiled. This is
82 nigel 75 equivalent to adding <b>/M</b> to each regular expression. For compatibility
83     with earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>.
84 nigel 63 </P>
85     <P>
86     <b>-o</b> <i>osize</i>
87 nigel 75 Set the number of elements in the output vector that is used when calling
88 nigel 93 <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> to be <i>osize</i>. The default value
89     is 45, which is enough for 14 capturing subexpressions for <b>pcre_exec()</b> or
90     22 different matches for <b>pcre_dfa_exec()</b>. The vector size can be
91     changed for individual matching calls by including \O in the data line (see
92     below).
93 nigel 63 </P>
94     <P>
95     <b>-p</b>
96 nigel 77 Behave as if each regex has the <b>/P</b> modifier; the POSIX wrapper API is
97     used to call PCRE. None of the other options has any effect when <b>-p</b> is
98     set.
99 nigel 63 </P>
100     <P>
101 nigel 91 <b>-q</b>
102 nigel 87 Do not output the version number of <b>pcretest</b> at the start of execution.
103     </P>
104     <P>
105 nigel 91 <b>-S</b> <i>size</i>
106     On Unix-like systems, set the size of the runtime stack to <i>size</i>
107     megabytes.
108     </P>
109     <P>
110 nigel 63 <b>-t</b>
111     Run each compile, study, and match many times with a timer, and output
112 nigel 75 resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with
113     <b>-t</b>, because you will then get the size output a zillion times, and the
114 nigel 93 timing will be distorted. You can control the number of iterations that are
115     used for timing by following <b>-t</b> with a number (as a separate item on the
116     command line). For example, "-t 1000" would iterate 1000 times. The default is
117     to iterate 500000 times.
118 nigel 63 </P>
119 nigel 93 <P>
120     <b>-tm</b>
121     This is like <b>-t</b> except that it times only the matching phase, not the
122     compile or study phases.
123     </P>
124 nigel 63 <br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br>
125     <P>
126     If <b>pcretest</b> is given two filename arguments, it reads from the first and
127     writes to the second. If it is given only one filename argument, it reads from
128     that file and writes to stdout. Otherwise, it reads from stdin and writes to
129     stdout, and prompts for each line of input, using "re&#62;" to prompt for regular
130     expressions, and "data&#62;" to prompt for data lines.
131     </P>
132     <P>
133     The program handles any number of sets of input on a single input file. Each
134     set starts with a regular expression, and continues with any number of data
135     lines to be matched against the pattern.
136     </P>
137     <P>
138 nigel 75 Each data line is matched separately and independently. If you want to do
139 nigel 91 multi-line matches, you have to use the \n escape sequence (or \r or \r\n,
140 nigel 93 etc., depending on the newline setting) in a single line of input to encode the
141     newline sequences. There is no limit on the length of data lines; the input
142 nigel 91 buffer is automatically extended if it is too small.
143 nigel 63 </P>
144     <P>
145     An empty line signals the end of the data lines, at which point a new regular
146     expression is read. The regular expressions are given enclosed in any
147 nigel 91 non-alphanumeric delimiters other than backslash, for example:
148 nigel 63 <pre>
149     /(a|bc)x+yz/
150 nigel 75 </pre>
151 nigel 63 White space before the initial delimiter is ignored. A regular expression may
152     be continued over several input lines, in which case the newline characters are
153     included within it. It is possible to include the delimiter within the pattern
154     by escaping it, for example
155     <pre>
156     /abc\/def/
157 nigel 75 </pre>
158 nigel 63 If you do so, the escape and the delimiter form part of the pattern, but since
159 nigel 75 delimiters are always non-alphanumeric, this does not affect its interpretation.
160 nigel 63 If the terminating delimiter is immediately followed by a backslash, for
161     example,
162     <pre>
163     /abc/\
164 nigel 75 </pre>
165 nigel 63 then a backslash is added to the end of the pattern. This is done to provide a
166     way of testing the error condition that arises if a pattern finishes with a
167     backslash, because
168     <pre>
169     /abc\/
170 nigel 75 </pre>
171 nigel 63 is interpreted as the first line of a pattern that starts with "abc/", causing
172     pcretest to read the next line as a continuation of the regular expression.
173     </P>
174     <br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br>
175     <P>
176 nigel 75 A pattern may be followed by any number of modifiers, which are mostly single
177     characters. Following Perl usage, these are referred to below as, for example,
178     "the <b>/i</b> modifier", even though the delimiter of the pattern need not
179     always be a slash, and no slash is used when writing modifiers. Whitespace may
180     appear between the final pattern delimiter and the first modifier, and between
181     the modifiers themselves.
182 nigel 63 </P>
183     <P>
184 nigel 75 The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
185     PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
186     <b>pcre_compile()</b> is called. These four modifier letters have the same
187     effect as they do in Perl. For example:
188 nigel 63 <pre>
189     /caseless/i
190 nigel 75 </pre>
191     The following table shows additional modifiers for setting PCRE options that do
192     not correspond to anything in Perl:
193     <pre>
194 nigel 91 <b>/A</b> PCRE_ANCHORED
195     <b>/C</b> PCRE_AUTO_CALLOUT
196     <b>/E</b> PCRE_DOLLAR_ENDONLY
197     <b>/f</b> PCRE_FIRSTLINE
198     <b>/J</b> PCRE_DUPNAMES
199     <b>/N</b> PCRE_NO_AUTO_CAPTURE
200     <b>/U</b> PCRE_UNGREEDY
201     <b>/X</b> PCRE_EXTRA
202     <b>/&#60;cr&#62;</b> PCRE_NEWLINE_CR
203     <b>/&#60;lf&#62;</b> PCRE_NEWLINE_LF
204     <b>/&#60;crlf&#62;</b> PCRE_NEWLINE_CRLF
205 nigel 93 <b>/&#60;any&#62;</b> PCRE_NEWLINE_ANY
206 nigel 75 </pre>
207 nigel 93 Those specifying line ending sequencess are literal strings as shown. This
208     example sets multiline matching with CRLF as the line ending sequence:
209     <pre>
210     /^abc/m&#60;crlf&#62;
211     </pre>
212     Details of the meanings of these PCRE options are given in the
213 nigel 91 <a href="pcreapi.html"><b>pcreapi</b></a>
214     documentation.
215     </P>
216     <br><b>
217     Finding all matches in a string
218     </b><br>
219     <P>
220 nigel 63 Searching for all possible matches within each subject string can be requested
221     by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
222     again to search the remainder of the subject string. The difference between
223     <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
224     <b>pcre_exec()</b> to start searching at a new point within the entire string
225     (which is in effect what Perl does), whereas the latter passes over a shortened
226     substring. This makes a difference to the matching process if the pattern
227     begins with a lookbehind assertion (including \b or \B).
228     </P>
229     <P>
230     If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an
231     empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
232     flags set in order to search for another, non-empty, match at the same point.
233     If this second match fails, the start offset is advanced by one, and the normal
234     match is retried. This imitates the way Perl handles such cases when using the
235     <b>/g</b> modifier or the <b>split()</b> function.
236     </P>
237 nigel 91 <br><b>
238     Other modifiers
239     </b><br>
240 nigel 63 <P>
241 nigel 75 There are yet more modifiers for controlling the way <b>pcretest</b>
242 nigel 63 operates.
243     </P>
244     <P>
245     The <b>/+</b> modifier requests that as well as outputting the substring that
246     matched the entire pattern, pcretest should in addition output the remainder of
247     the subject string. This is useful for tests where the subject contains
248     multiple copies of the same substring.
249     </P>
250     <P>
251 nigel 93 The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
252 ph10 123 output a representation of the compiled byte code after compilation. Normally
253     this information contains length and offset values; however, if <b>/Z</b> is
254     also present, this data is replaced by spaces. This is a special feature for
255     use in the automatic test scripts; it ensures that the same output is generated
256     for different internal link sizes.
257 nigel 93 </P>
258     <P>
259 nigel 63 The <b>/L</b> modifier must be followed directly by the name of a locale, for
260     example,
261     <pre>
262 nigel 75 /pattern/Lfr_FR
263     </pre>
264     For this reason, it must be the last modifier. The given locale is set,
265 nigel 63 <b>pcre_maketables()</b> is called to build a set of character tables for the
266     locale, and this is then passed to <b>pcre_compile()</b> when compiling the
267     regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables
268     pointer; that is, <b>/L</b> applies only to the expression on which it appears.
269     </P>
270     <P>
271     The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
272 nigel 75 compiled pattern (whether it is anchored, has a fixed first character, and
273     so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
274     pattern. If the pattern is studied, the results of that are also output.
275 nigel 63 </P>
276     <P>
277 nigel 93 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
278 ph10 148 <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
279 nigel 63 </P>
280     <P>
281 nigel 75 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
282     fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
283     facility is for testing the feature in PCRE that allows it to execute patterns
284     that were compiled on a host with a different endianness. This feature is not
285     available when the POSIX interface to PCRE is being used, that is, when the
286     <b>/P</b> pattern modifier is specified. See also the section about saving and
287     reloading compiled patterns below.
288     </P>
289     <P>
290 nigel 63 The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the
291     expression has been compiled, and the results used when the expression is
292     matched.
293     </P>
294     <P>
295     The <b>/M</b> modifier causes the size of memory block used to hold the compiled
296     pattern to be output.
297     </P>
298     <P>
299     The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
300     API rather than its native API. When this is done, all other modifiers except
301     <b>/i</b>, <b>/m</b>, and <b>/+</b> are ignored. REG_ICASE is set if <b>/i</b> is
302     present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions
303     force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
304     </P>
305     <P>
306     The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8
307     option set. This turns on support for UTF-8 character handling in PCRE,
308     provided that it was compiled with this support enabled. This modifier also
309     causes any non-printing characters in output strings to be printed using the
310     \x{hh...} notation if they are valid UTF-8 sequences.
311     </P>
312 nigel 71 <P>
313     If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to
314     call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the
315     checking of the string for UTF-8 validity.
316     </P>
317 nigel 75 <br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
318 nigel 63 <P>
319     Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
320     whitespace is removed, and it is then scanned for \ escapes. Some of these are
321     pretty esoteric features, intended for checking out some of the more
322     complicated features of PCRE. If you are just testing "ordinary" regular
323     expressions, you probably don't need any of these. The following escapes are
324     recognized:
325     <pre>
326 nigel 93 \a alarm (BEL, \x07)
327     \b backspace (\x08)
328     \e escape (\x27)
329     \f formfeed (\x0c)
330     \n newline (\x0a)
331 nigel 91 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
332 nigel 93 \r carriage return (\x0d)
333     \t tab (\x09)
334     \v vertical tab (\x0b)
335 nigel 63 \nnn octal character (up to 3 octal digits)
336     \xhh hexadecimal character (up to 2 hex digits)
337 nigel 75 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode
338 nigel 91 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
339     \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
340 nigel 75 \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32)
341     \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
342 nigel 63 ated by next non alphanumeric character)
343 nigel 75 \C+ show the current captured substrings at callout time
344 nigel 63 \C- do not supply a callout function
345 nigel 75 \C!n return 1 instead of 0 when callout number n is reached
346     \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
347     \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
348 nigel 77 \D use the <b>pcre_dfa_exec()</b> match function
349     \F only shortest match for <b>pcre_dfa_exec()</b>
350 nigel 75 \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32)
351     \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin-
352 nigel 63 ated by next non-alphanumeric character)
353 nigel 75 \L call pcre_get_substringlist() after a successful match
354 nigel 91 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
355     \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
356 nigel 75 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
357 nigel 77 \P pass the PCRE_PARTIAL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
358 nigel 91 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
359 nigel 77 \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
360 nigel 73 \S output details of memory get/free calls during matching
361 nigel 91 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
362     \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
363 nigel 75 \&#62;dd start the match at offset dd (any number of digits);
364 nigel 91 this sets the <i>startoffset</i> argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
365     \&#60;cr&#62; pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
366     \&#60;lf&#62; pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
367     \&#60;crlf&#62; pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
368 nigel 93 \&#60;any&#62; pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
369 nigel 75 </pre>
370 nigel 93 The escapes that specify line ending sequences are literal strings, exactly as
371     shown. No more than one newline setting should be present in any data line.
372 nigel 63 </P>
373     <P>
374 nigel 93 A backslash followed by anything else just escapes the anything else. If
375     the very last character is a backslash, it is ignored. This gives a way of
376     passing an empty line as data, since a real empty line terminates the data
377     input.
378     </P>
379     <P>
380 nigel 63 If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
381 nigel 87 different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
382     fields of the <b>pcre_extra</b> data structure, until it finds the minimum
383     numbers for each parameter that allow <b>pcre_exec()</b> to complete. The
384     <i>match_limit</i> number is a measure of the amount of backtracking that takes
385     place, and checking it out can be instructive. For most simple matches, the
386     number is quite small, but for patterns with very large numbers of matching
387     possibilities, it can become large very quickly with increasing length of
388     subject string. The <i>match_limit_recursion</i> number is a measure of how much
389     stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed
390     to complete the match attempt.
391 nigel 63 </P>
392     <P>
393 nigel 75 When \O is used, the value specified may be higher or lower than the size set
394     by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
395     the call of <b>pcre_exec()</b> for the line in which it appears.
396 nigel 63 </P>
397     <P>
398 nigel 75 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
399 nigel 87 API to be used, the only option-setting sequences that have any effect are \B
400     and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to
401     <b>regexec()</b>.
402 nigel 63 </P>
403     <P>
404     The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
405     of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
406     any number of hexadecimal digits inside the braces. The result is from one to
407     six bytes, encoded according to the UTF-8 rules.
408     </P>
409 nigel 77 <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
410 nigel 63 <P>
411 nigel 77 By default, <b>pcretest</b> uses the standard PCRE matching function,
412     <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
413     alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
414     different way, and has some restrictions. The differences between the two
415     functions are described in the
416     <a href="pcrematching.html"><b>pcrematching</b></a>
417     documentation.
418     </P>
419     <P>
420     If a data line contains the \D escape sequence, or if the command line
421     contains the <b>-dfa</b> option, the alternative matching function is called.
422     This function finds all possible matches at a given point. If, however, the \F
423     escape sequence is present in the data line, it stops after the first match is
424     found. This is always the shortest possible match.
425     </P>
426     <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
427     <P>
428     This section describes the output when the normal matching function,
429     <b>pcre_exec()</b>, is being used.
430     </P>
431     <P>
432 nigel 63 When a match succeeds, pcretest outputs the list of captured substrings that
433     <b>pcre_exec()</b> returns, starting with number 0 for the string that matched
434 nigel 75 the whole pattern. Otherwise, it outputs "No match" or "Partial match"
435     when <b>pcre_exec()</b> returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PARTIAL,
436     respectively, and otherwise the PCRE negative error number. Here is an example
437 nigel 77 of an interactive <b>pcretest</b> run.
438 nigel 63 <pre>
439     $ pcretest
440 nigel 93 PCRE version 7.0 30-Nov-2006
441 nigel 75
442 nigel 63 re&#62; /^abc(\d+)/
443     data&#62; abc123
444     0: abc123
445     1: 123
446     data&#62; xyz
447     No match
448 nigel 75 </pre>
449 nigel 63 If the strings contain any non-printing characters, they are output as \0x
450     escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
451 nigel 93 pattern. See below for the definition of non-printing characters. If the
452     pattern has the <b>/+</b> modifier, the output for substring 0 is followed by
453     the the rest of the subject string, identified by "0+" like this:
454 nigel 63 <pre>
455     re&#62; /cat/+
456     data&#62; cataract
457     0: cat
458     0+ aract
459 nigel 75 </pre>
460 nigel 63 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
461     matching attempts are output in sequence, like this:
462     <pre>
463     re&#62; /\Bi(\w\w)/g
464     data&#62; Mississippi
465     0: iss
466     1: ss
467     0: iss
468     1: ss
469     0: ipp
470     1: pp
471 nigel 75 </pre>
472 nigel 63 "No match" is output only if the first match attempt fails.
473     </P>
474     <P>
475     If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
476     data line that is successfully matched, the substrings extracted by the
477     convenience functions are output with C, G, or L after the string number
478     instead of a colon. This is in addition to the normal full list. The string
479     length (that is, the return from the extraction function) is given in
480     parentheses after each string for <b>\C</b> and <b>\G</b>.
481     </P>
482     <P>
483 nigel 93 Note that whereas patterns can be continued over several lines (a plain "&#62;"
484 nigel 63 prompt is used for continuations), data lines may not. However newlines can be
485 nigel 93 included in data by means of the \n escape (or \r, \r\n, etc., depending on
486     the newline sequence setting).
487 nigel 63 </P>
488 nigel 77 <br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
489 nigel 63 <P>
490 nigel 77 When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
491     means of the \D escape sequence or the <b>-dfa</b> command line option), the
492     output consists of a list of all the matches that start at the first point in
493     the subject where there is at least one match. For example:
494     <pre>
495     re&#62; /(tang|tangerine|tan)/
496     data&#62; yellow tangerine\D
497     0: tangerine
498     1: tang
499     2: tan
500     </pre>
501     (Using the normal matching function on this data finds only "tang".) The
502     longest matching string is always given first (and numbered zero).
503     </P>
504     <P>
505 nigel 93 If <b>/g</b> is present on the pattern, the search for further matches resumes
506 nigel 77 at the end of the longest match. For example:
507     <pre>
508     re&#62; /(tang|tangerine|tan)/g
509     data&#62; yellow tangerine and tangy sultana\D
510     0: tangerine
511     1: tang
512     2: tan
513     0: tang
514     1: tan
515     0: tan
516     </pre>
517     Since the matching function does not support substring capture, the escape
518     sequences that are concerned with captured substrings are not relevant.
519     </P>
520     <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
521     <P>
522     When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
523     indicating that the subject partially matched the pattern, you can restart the
524     match with additional subject data by means of the \R escape sequence. For
525     example:
526     <pre>
527     re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
528     data&#62; 23ja\P\D
529     Partial match: 23ja
530     data&#62; n05\R\D
531     0: n05
532     </pre>
533     For further information about partial matching, see the
534     <a href="pcrepartial.html"><b>pcrepartial</b></a>
535     documentation.
536     </P>
537     <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
538     <P>
539 nigel 75 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
540 nigel 77 is called during matching. This works with both matching functions. By default,
541     the called function displays the callout number, the start and current
542     positions in the text at the callout time, and the next pattern item to be
543     tested. For example, the output
544 nigel 75 <pre>
545     ---&#62;pqrabcdef
546     0 ^ ^ \d
547     </pre>
548     indicates that callout number 0 occurred for a match attempt starting at the
549     fourth character of the subject string, when the pointer was at the seventh
550     character of the data, and when the next pattern item was \d. Just one
551     circumflex is output if the start and current positions are the same.
552     </P>
553     <P>
554     Callouts numbered 255 are assumed to be automatic callouts, inserted as a
555     result of the <b>/C</b> pattern modifier. In this case, instead of showing the
556     callout number, the offset in the pattern, preceded by a plus, is output. For
557     example:
558     <pre>
559     re&#62; /\d?[A-E]\*/C
560     data&#62; E*
561     ---&#62;E*
562     +0 ^ \d?
563     +3 ^ [A-E]
564     +8 ^^ \*
565     +10 ^ ^
566     0: E*
567     </pre>
568     The callout function in <b>pcretest</b> returns zero (carry on matching) by
569 nigel 77 default, but you can use a \C item in a data line (as described above) to
570 nigel 75 change this.
571     </P>
572     <P>
573     Inserting callouts can be helpful when using <b>pcretest</b> to check
574     complicated regular expressions. For further information about callouts, see
575     the
576     <a href="pcrecallout.html"><b>pcrecallout</b></a>
577     documentation.
578     </P>
579 nigel 93 <br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
580 nigel 75 <P>
581 nigel 93 When <b>pcretest</b> is outputting text in the compiled version of a pattern,
582     bytes other than 32-126 are always treated as non-printing characters are are
583     therefore shown as hex escapes.
584     </P>
585     <P>
586     When <b>pcretest</b> is outputting text that is a matched part of a subject
587     string, it behaves in the same way, unless a different locale has been set for
588     the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
589     function to distinguish printing and non-printing characters.
590     </P>
591     <br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
592     <P>
593 nigel 75 The facilities described in this section are not available when the POSIX
594     inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
595     specified.
596     </P>
597     <P>
598     When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
599     compiled pattern to a file, by following the modifiers with &#62; and a file name.
600     For example:
601     <pre>
602     /pattern/im &#62;/some/file
603     </pre>
604     See the
605     <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
606     documentation for a discussion about saving and re-using compiled patterns.
607     </P>
608     <P>
609     The data that is written is binary. The first eight bytes are the length of the
610     compiled pattern data followed by the length of the optional study data, each
611     written as four bytes in big-endian order (most significant byte first). If
612     there is no study data (either the pattern was not studied, or studying did not
613     return any data), the second length is zero. The lengths are followed by an
614     exact copy of the compiled pattern. If there is additional study data, this
615     follows immediately after the compiled pattern. After writing the file,
616     <b>pcretest</b> expects to read a new pattern.
617     </P>
618     <P>
619     A saved pattern can be reloaded into <b>pcretest</b> by specifing &#60; and a file
620     name instead of a pattern. The name of the file must not contain a &#60; character,
621     as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by &#60;
622     characters.
623     For example:
624     <pre>
625     re&#62; &#60;/some/file
626     Compiled regex loaded from /some/file
627     No study data
628     </pre>
629     When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in
630     the usual way.
631     </P>
632     <P>
633     You can copy a file written by <b>pcretest</b> to a different host and reload it
634     there, even if the new host has opposite endianness to the one on which the
635     pattern was compiled. For example, you can compile on an i86 machine and run on
636     a SPARC machine.
637     </P>
638     <P>
639     File names for saving and reloading can be absolute or relative, but note that
640     the shell facility of expanding a file name that starts with a tilde (~) is not
641     available.
642     </P>
643     <P>
644     The ability to save and reload files in <b>pcretest</b> is intended for testing
645     and experimentation. It is not intended for production use because only a
646     single pattern can be written to a file. Furthermore, there is no facility for
647     supplying custom character tables for use with a reloaded pattern. If the
648     original pattern was compiled with custom tables, an attempt to match a subject
649     string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
650     Finally, if you attempt to load a file that is not in the correct format, the
651     result is undefined.
652     </P>
653 nigel 93 <br><a name="SEC13" href="#TOC1">SEE ALSO</a><br>
654 nigel 75 <P>
655 nigel 93 <b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3),
656 ph10 148 <b>pcrepartial</b>(d), <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3).
657 nigel 93 </P>
658     <br><a name="SEC14" href="#TOC1">AUTHOR</a><br>
659     <P>
660 nigel 77 Philip Hazel
661 nigel 63 <br>
662 ph10 99 University Computing Service
663 nigel 63 <br>
664 nigel 93 Cambridge CB2 3QH, England.
665 ph10 99 <br>
666 nigel 63 </P>
667 ph10 99 <br><a name="SEC15" href="#TOC1">REVISION</a><br>
668 nigel 63 <P>
669 ph10 99 Last updated: 06 March 2007
670 nigel 63 <br>
671 ph10 99 Copyright &copy; 1997-2007 University of Cambridge.
672     <br>
673 nigel 75 <p>
674     Return to the <a href="index.html">PCRE index page</a>.
675     </p>

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