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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 ph10 150 <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 ph10 152 <b>/&#60;anycrlf&#62;</b> PCRE_NEWLINE_ANYCRLF
206 ph10 150 <b>/&#60;any&#62;</b> PCRE_NEWLINE_ANY
207 nigel 75 </pre>
208 nigel 93 Those specifying line ending sequencess are literal strings as shown. This
209     example sets multiline matching with CRLF as the line ending sequence:
210     <pre>
211     /^abc/m&#60;crlf&#62;
212     </pre>
213     Details of the meanings of these PCRE options are given in the
214 nigel 91 <a href="pcreapi.html"><b>pcreapi</b></a>
215     documentation.
216     </P>
217     <br><b>
218     Finding all matches in a string
219     </b><br>
220     <P>
221 nigel 63 Searching for all possible matches within each subject string can be requested
222     by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
223     again to search the remainder of the subject string. The difference between
224     <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
225     <b>pcre_exec()</b> to start searching at a new point within the entire string
226     (which is in effect what Perl does), whereas the latter passes over a shortened
227     substring. This makes a difference to the matching process if the pattern
228     begins with a lookbehind assertion (including \b or \B).
229     </P>
230     <P>
231     If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an
232     empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
233     flags set in order to search for another, non-empty, match at the same point.
234     If this second match fails, the start offset is advanced by one, and the normal
235     match is retried. This imitates the way Perl handles such cases when using the
236     <b>/g</b> modifier or the <b>split()</b> function.
237     </P>
238 nigel 91 <br><b>
239     Other modifiers
240     </b><br>
241 nigel 63 <P>
242 nigel 75 There are yet more modifiers for controlling the way <b>pcretest</b>
243 nigel 63 operates.
244     </P>
245     <P>
246     The <b>/+</b> modifier requests that as well as outputting the substring that
247     matched the entire pattern, pcretest should in addition output the remainder of
248     the subject string. This is useful for tests where the subject contains
249     multiple copies of the same substring.
250     </P>
251     <P>
252 nigel 93 The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
253 ph10 123 output a representation of the compiled byte code after compilation. Normally
254     this information contains length and offset values; however, if <b>/Z</b> is
255     also present, this data is replaced by spaces. This is a special feature for
256     use in the automatic test scripts; it ensures that the same output is generated
257     for different internal link sizes.
258 nigel 93 </P>
259     <P>
260 nigel 63 The <b>/L</b> modifier must be followed directly by the name of a locale, for
261     example,
262     <pre>
263 nigel 75 /pattern/Lfr_FR
264     </pre>
265     For this reason, it must be the last modifier. The given locale is set,
266 nigel 63 <b>pcre_maketables()</b> is called to build a set of character tables for the
267     locale, and this is then passed to <b>pcre_compile()</b> when compiling the
268     regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables
269     pointer; that is, <b>/L</b> applies only to the expression on which it appears.
270     </P>
271     <P>
272     The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
273 nigel 75 compiled pattern (whether it is anchored, has a fixed first character, and
274     so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
275     pattern. If the pattern is studied, the results of that are also output.
276 nigel 63 </P>
277     <P>
278 nigel 93 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
279 ph10 148 <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
280 nigel 63 </P>
281     <P>
282 nigel 75 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
283     fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
284     facility is for testing the feature in PCRE that allows it to execute patterns
285     that were compiled on a host with a different endianness. This feature is not
286     available when the POSIX interface to PCRE is being used, that is, when the
287     <b>/P</b> pattern modifier is specified. See also the section about saving and
288     reloading compiled patterns below.
289     </P>
290     <P>
291 nigel 63 The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the
292     expression has been compiled, and the results used when the expression is
293     matched.
294     </P>
295     <P>
296     The <b>/M</b> modifier causes the size of memory block used to hold the compiled
297     pattern to be output.
298     </P>
299     <P>
300     The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
301     API rather than its native API. When this is done, all other modifiers except
302     <b>/i</b>, <b>/m</b>, and <b>/+</b> are ignored. REG_ICASE is set if <b>/i</b> is
303     present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions
304     force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
305     </P>
306     <P>
307     The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8
308     option set. This turns on support for UTF-8 character handling in PCRE,
309     provided that it was compiled with this support enabled. This modifier also
310     causes any non-printing characters in output strings to be printed using the
311     \x{hh...} notation if they are valid UTF-8 sequences.
312     </P>
313 nigel 71 <P>
314     If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to
315     call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the
316     checking of the string for UTF-8 validity.
317     </P>
318 nigel 75 <br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
319 nigel 63 <P>
320     Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
321     whitespace is removed, and it is then scanned for \ escapes. Some of these are
322     pretty esoteric features, intended for checking out some of the more
323     complicated features of PCRE. If you are just testing "ordinary" regular
324     expressions, you probably don't need any of these. The following escapes are
325     recognized:
326     <pre>
327 nigel 93 \a alarm (BEL, \x07)
328     \b backspace (\x08)
329     \e escape (\x27)
330     \f formfeed (\x0c)
331     \n newline (\x0a)
332 nigel 91 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
333 nigel 93 \r carriage return (\x0d)
334     \t tab (\x09)
335     \v vertical tab (\x0b)
336 nigel 63 \nnn octal character (up to 3 octal digits)
337     \xhh hexadecimal character (up to 2 hex digits)
338 nigel 75 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode
339 nigel 91 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
340     \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
341 nigel 75 \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32)
342     \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
343 nigel 63 ated by next non alphanumeric character)
344 nigel 75 \C+ show the current captured substrings at callout time
345 nigel 63 \C- do not supply a callout function
346 nigel 75 \C!n return 1 instead of 0 when callout number n is reached
347     \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
348     \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
349 nigel 77 \D use the <b>pcre_dfa_exec()</b> match function
350     \F only shortest match for <b>pcre_dfa_exec()</b>
351 nigel 75 \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32)
352     \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin-
353 nigel 63 ated by next non-alphanumeric character)
354 nigel 75 \L call pcre_get_substringlist() after a successful match
355 nigel 91 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
356     \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
357 nigel 75 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
358 nigel 77 \P pass the PCRE_PARTIAL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
359 nigel 91 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
360 nigel 77 \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
361 nigel 73 \S output details of memory get/free calls during matching
362 nigel 91 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
363     \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
364 nigel 75 \&#62;dd start the match at offset dd (any number of digits);
365 nigel 91 this sets the <i>startoffset</i> argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
366     \&#60;cr&#62; pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
367     \&#60;lf&#62; pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
368     \&#60;crlf&#62; pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
369 ph10 150 \&#60;anycrlf&#62; pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
370 nigel 93 \&#60;any&#62; pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
371 nigel 75 </pre>
372 nigel 93 The escapes that specify line ending sequences are literal strings, exactly as
373     shown. No more than one newline setting should be present in any data line.
374 nigel 63 </P>
375     <P>
376 nigel 93 A backslash followed by anything else just escapes the anything else. If
377     the very last character is a backslash, it is ignored. This gives a way of
378     passing an empty line as data, since a real empty line terminates the data
379     input.
380     </P>
381     <P>
382 nigel 63 If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
383 nigel 87 different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
384     fields of the <b>pcre_extra</b> data structure, until it finds the minimum
385     numbers for each parameter that allow <b>pcre_exec()</b> to complete. The
386     <i>match_limit</i> number is a measure of the amount of backtracking that takes
387     place, and checking it out can be instructive. For most simple matches, the
388     number is quite small, but for patterns with very large numbers of matching
389     possibilities, it can become large very quickly with increasing length of
390     subject string. The <i>match_limit_recursion</i> number is a measure of how much
391     stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed
392     to complete the match attempt.
393 nigel 63 </P>
394     <P>
395 nigel 75 When \O is used, the value specified may be higher or lower than the size set
396     by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
397     the call of <b>pcre_exec()</b> for the line in which it appears.
398 nigel 63 </P>
399     <P>
400 nigel 75 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
401 nigel 87 API to be used, the only option-setting sequences that have any effect are \B
402     and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to
403     <b>regexec()</b>.
404 nigel 63 </P>
405     <P>
406     The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
407     of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
408     any number of hexadecimal digits inside the braces. The result is from one to
409     six bytes, encoded according to the UTF-8 rules.
410     </P>
411 nigel 77 <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
412 nigel 63 <P>
413 nigel 77 By default, <b>pcretest</b> uses the standard PCRE matching function,
414     <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
415     alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
416     different way, and has some restrictions. The differences between the two
417     functions are described in the
418     <a href="pcrematching.html"><b>pcrematching</b></a>
419     documentation.
420     </P>
421     <P>
422     If a data line contains the \D escape sequence, or if the command line
423     contains the <b>-dfa</b> option, the alternative matching function is called.
424     This function finds all possible matches at a given point. If, however, the \F
425     escape sequence is present in the data line, it stops after the first match is
426     found. This is always the shortest possible match.
427     </P>
428     <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
429     <P>
430     This section describes the output when the normal matching function,
431     <b>pcre_exec()</b>, is being used.
432     </P>
433     <P>
434 nigel 63 When a match succeeds, pcretest outputs the list of captured substrings that
435     <b>pcre_exec()</b> returns, starting with number 0 for the string that matched
436 nigel 75 the whole pattern. Otherwise, it outputs "No match" or "Partial match"
437     when <b>pcre_exec()</b> returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PARTIAL,
438     respectively, and otherwise the PCRE negative error number. Here is an example
439 nigel 77 of an interactive <b>pcretest</b> run.
440 nigel 63 <pre>
441     $ pcretest
442 nigel 93 PCRE version 7.0 30-Nov-2006
443 nigel 75
444 nigel 63 re&#62; /^abc(\d+)/
445     data&#62; abc123
446     0: abc123
447     1: 123
448     data&#62; xyz
449     No match
450 nigel 75 </pre>
451 nigel 63 If the strings contain any non-printing characters, they are output as \0x
452     escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
453 nigel 93 pattern. See below for the definition of non-printing characters. If the
454     pattern has the <b>/+</b> modifier, the output for substring 0 is followed by
455     the the rest of the subject string, identified by "0+" like this:
456 nigel 63 <pre>
457     re&#62; /cat/+
458     data&#62; cataract
459     0: cat
460     0+ aract
461 nigel 75 </pre>
462 nigel 63 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
463     matching attempts are output in sequence, like this:
464     <pre>
465     re&#62; /\Bi(\w\w)/g
466     data&#62; Mississippi
467     0: iss
468     1: ss
469     0: iss
470     1: ss
471     0: ipp
472     1: pp
473 nigel 75 </pre>
474 nigel 63 "No match" is output only if the first match attempt fails.
475     </P>
476     <P>
477     If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
478     data line that is successfully matched, the substrings extracted by the
479     convenience functions are output with C, G, or L after the string number
480     instead of a colon. This is in addition to the normal full list. The string
481     length (that is, the return from the extraction function) is given in
482     parentheses after each string for <b>\C</b> and <b>\G</b>.
483     </P>
484     <P>
485 nigel 93 Note that whereas patterns can be continued over several lines (a plain "&#62;"
486 nigel 63 prompt is used for continuations), data lines may not. However newlines can be
487 nigel 93 included in data by means of the \n escape (or \r, \r\n, etc., depending on
488     the newline sequence setting).
489 nigel 63 </P>
490 nigel 77 <br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
491 nigel 63 <P>
492 nigel 77 When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
493     means of the \D escape sequence or the <b>-dfa</b> command line option), the
494     output consists of a list of all the matches that start at the first point in
495     the subject where there is at least one match. For example:
496     <pre>
497     re&#62; /(tang|tangerine|tan)/
498     data&#62; yellow tangerine\D
499     0: tangerine
500     1: tang
501     2: tan
502     </pre>
503     (Using the normal matching function on this data finds only "tang".) The
504     longest matching string is always given first (and numbered zero).
505     </P>
506     <P>
507 nigel 93 If <b>/g</b> is present on the pattern, the search for further matches resumes
508 nigel 77 at the end of the longest match. For example:
509     <pre>
510     re&#62; /(tang|tangerine|tan)/g
511     data&#62; yellow tangerine and tangy sultana\D
512     0: tangerine
513     1: tang
514     2: tan
515     0: tang
516     1: tan
517     0: tan
518     </pre>
519     Since the matching function does not support substring capture, the escape
520     sequences that are concerned with captured substrings are not relevant.
521     </P>
522     <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
523     <P>
524     When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
525     indicating that the subject partially matched the pattern, you can restart the
526     match with additional subject data by means of the \R escape sequence. For
527     example:
528     <pre>
529     re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
530     data&#62; 23ja\P\D
531     Partial match: 23ja
532     data&#62; n05\R\D
533     0: n05
534     </pre>
535     For further information about partial matching, see the
536     <a href="pcrepartial.html"><b>pcrepartial</b></a>
537     documentation.
538     </P>
539     <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
540     <P>
541 nigel 75 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
542 nigel 77 is called during matching. This works with both matching functions. By default,
543     the called function displays the callout number, the start and current
544     positions in the text at the callout time, and the next pattern item to be
545     tested. For example, the output
546 nigel 75 <pre>
547     ---&#62;pqrabcdef
548     0 ^ ^ \d
549     </pre>
550     indicates that callout number 0 occurred for a match attempt starting at the
551     fourth character of the subject string, when the pointer was at the seventh
552     character of the data, and when the next pattern item was \d. Just one
553     circumflex is output if the start and current positions are the same.
554     </P>
555     <P>
556     Callouts numbered 255 are assumed to be automatic callouts, inserted as a
557     result of the <b>/C</b> pattern modifier. In this case, instead of showing the
558     callout number, the offset in the pattern, preceded by a plus, is output. For
559     example:
560     <pre>
561     re&#62; /\d?[A-E]\*/C
562     data&#62; E*
563     ---&#62;E*
564     +0 ^ \d?
565     +3 ^ [A-E]
566     +8 ^^ \*
567     +10 ^ ^
568     0: E*
569     </pre>
570     The callout function in <b>pcretest</b> returns zero (carry on matching) by
571 nigel 77 default, but you can use a \C item in a data line (as described above) to
572 nigel 75 change this.
573     </P>
574     <P>
575     Inserting callouts can be helpful when using <b>pcretest</b> to check
576     complicated regular expressions. For further information about callouts, see
577     the
578     <a href="pcrecallout.html"><b>pcrecallout</b></a>
579     documentation.
580     </P>
581 nigel 93 <br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
582 nigel 75 <P>
583 nigel 93 When <b>pcretest</b> is outputting text in the compiled version of a pattern,
584     bytes other than 32-126 are always treated as non-printing characters are are
585     therefore shown as hex escapes.
586     </P>
587     <P>
588     When <b>pcretest</b> is outputting text that is a matched part of a subject
589     string, it behaves in the same way, unless a different locale has been set for
590     the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
591     function to distinguish printing and non-printing characters.
592     </P>
593     <br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
594     <P>
595 nigel 75 The facilities described in this section are not available when the POSIX
596     inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
597     specified.
598     </P>
599     <P>
600     When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
601     compiled pattern to a file, by following the modifiers with &#62; and a file name.
602     For example:
603     <pre>
604     /pattern/im &#62;/some/file
605     </pre>
606     See the
607     <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
608     documentation for a discussion about saving and re-using compiled patterns.
609     </P>
610     <P>
611     The data that is written is binary. The first eight bytes are the length of the
612     compiled pattern data followed by the length of the optional study data, each
613     written as four bytes in big-endian order (most significant byte first). If
614     there is no study data (either the pattern was not studied, or studying did not
615     return any data), the second length is zero. The lengths are followed by an
616     exact copy of the compiled pattern. If there is additional study data, this
617     follows immediately after the compiled pattern. After writing the file,
618     <b>pcretest</b> expects to read a new pattern.
619     </P>
620     <P>
621     A saved pattern can be reloaded into <b>pcretest</b> by specifing &#60; and a file
622     name instead of a pattern. The name of the file must not contain a &#60; character,
623     as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by &#60;
624     characters.
625     For example:
626     <pre>
627     re&#62; &#60;/some/file
628     Compiled regex loaded from /some/file
629     No study data
630     </pre>
631     When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in
632     the usual way.
633     </P>
634     <P>
635     You can copy a file written by <b>pcretest</b> to a different host and reload it
636     there, even if the new host has opposite endianness to the one on which the
637     pattern was compiled. For example, you can compile on an i86 machine and run on
638     a SPARC machine.
639     </P>
640     <P>
641     File names for saving and reloading can be absolute or relative, but note that
642     the shell facility of expanding a file name that starts with a tilde (~) is not
643     available.
644     </P>
645     <P>
646     The ability to save and reload files in <b>pcretest</b> is intended for testing
647     and experimentation. It is not intended for production use because only a
648     single pattern can be written to a file. Furthermore, there is no facility for
649     supplying custom character tables for use with a reloaded pattern. If the
650     original pattern was compiled with custom tables, an attempt to match a subject
651     string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
652     Finally, if you attempt to load a file that is not in the correct format, the
653     result is undefined.
654     </P>
655 nigel 93 <br><a name="SEC13" href="#TOC1">SEE ALSO</a><br>
656 nigel 75 <P>
657 nigel 93 <b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3),
658 ph10 148 <b>pcrepartial</b>(d), <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3).
659 nigel 93 </P>
660     <br><a name="SEC14" href="#TOC1">AUTHOR</a><br>
661     <P>
662 nigel 77 Philip Hazel
663 nigel 63 <br>
664 ph10 99 University Computing Service
665 nigel 63 <br>
666 nigel 93 Cambridge CB2 3QH, England.
667 ph10 99 <br>
668 nigel 63 </P>
669 ph10 99 <br><a name="SEC15" href="#TOC1">REVISION</a><br>
670 nigel 63 <P>
671 ph10 150 Last updated: 16 April 2007
672 nigel 63 <br>
673 ph10 99 Copyright &copy; 1997-2007 University of Cambridge.
674     <br>
675 nigel 75 <p>
676     Return to the <a href="index.html">PCRE index page</a>.
677     </p>

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