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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>
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     output a representation of the compiled byte code after compilation.
253     </P>
254     <P>
255 nigel 63 The <b>/L</b> modifier must be followed directly by the name of a locale, for
256     example,
257     <pre>
258 nigel 75 /pattern/Lfr_FR
259     </pre>
260     For this reason, it must be the last modifier. The given locale is set,
261 nigel 63 <b>pcre_maketables()</b> is called to build a set of character tables for the
262     locale, and this is then passed to <b>pcre_compile()</b> when compiling the
263     regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables
264     pointer; that is, <b>/L</b> applies only to the expression on which it appears.
265     </P>
266     <P>
267     The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
268 nigel 75 compiled pattern (whether it is anchored, has a fixed first character, and
269     so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
270     pattern. If the pattern is studied, the results of that are also output.
271 nigel 63 </P>
272     <P>
273 nigel 93 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
274     <b>/BI</b>, that is, both the \fP/B\fP and the <b>/I</b> modifiers.
275 nigel 63 </P>
276     <P>
277 nigel 75 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
278     fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
279     facility is for testing the feature in PCRE that allows it to execute patterns
280     that were compiled on a host with a different endianness. This feature is not
281     available when the POSIX interface to PCRE is being used, that is, when the
282     <b>/P</b> pattern modifier is specified. See also the section about saving and
283     reloading compiled patterns below.
284     </P>
285     <P>
286 nigel 63 The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the
287     expression has been compiled, and the results used when the expression is
288     matched.
289     </P>
290     <P>
291     The <b>/M</b> modifier causes the size of memory block used to hold the compiled
292     pattern to be output.
293     </P>
294     <P>
295     The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
296     API rather than its native API. When this is done, all other modifiers except
297     <b>/i</b>, <b>/m</b>, and <b>/+</b> are ignored. REG_ICASE is set if <b>/i</b> is
298     present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions
299     force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
300     </P>
301     <P>
302     The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8
303     option set. This turns on support for UTF-8 character handling in PCRE,
304     provided that it was compiled with this support enabled. This modifier also
305     causes any non-printing characters in output strings to be printed using the
306     \x{hh...} notation if they are valid UTF-8 sequences.
307     </P>
308 nigel 71 <P>
309     If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to
310     call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the
311     checking of the string for UTF-8 validity.
312     </P>
313 nigel 75 <br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
314 nigel 63 <P>
315     Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
316     whitespace is removed, and it is then scanned for \ escapes. Some of these are
317     pretty esoteric features, intended for checking out some of the more
318     complicated features of PCRE. If you are just testing "ordinary" regular
319     expressions, you probably don't need any of these. The following escapes are
320     recognized:
321     <pre>
322 nigel 93 \a alarm (BEL, \x07)
323     \b backspace (\x08)
324     \e escape (\x27)
325     \f formfeed (\x0c)
326     \n newline (\x0a)
327 nigel 91 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
328 nigel 93 \r carriage return (\x0d)
329     \t tab (\x09)
330     \v vertical tab (\x0b)
331 nigel 63 \nnn octal character (up to 3 octal digits)
332     \xhh hexadecimal character (up to 2 hex digits)
333 nigel 75 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode
334 nigel 91 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
335     \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
336 nigel 75 \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32)
337     \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
338 nigel 63 ated by next non alphanumeric character)
339 nigel 75 \C+ show the current captured substrings at callout time
340 nigel 63 \C- do not supply a callout function
341 nigel 75 \C!n return 1 instead of 0 when callout number n is reached
342     \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
343     \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
344 nigel 77 \D use the <b>pcre_dfa_exec()</b> match function
345     \F only shortest match for <b>pcre_dfa_exec()</b>
346 nigel 75 \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32)
347     \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin-
348 nigel 63 ated by next non-alphanumeric character)
349 nigel 75 \L call pcre_get_substringlist() after a successful match
350 nigel 91 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
351     \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
352 nigel 75 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
353 nigel 77 \P pass the PCRE_PARTIAL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
354 nigel 91 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
355 nigel 77 \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
356 nigel 73 \S output details of memory get/free calls during matching
357 nigel 91 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
358     \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
359 nigel 75 \&#62;dd start the match at offset dd (any number of digits);
360 nigel 91 this sets the <i>startoffset</i> argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
361     \&#60;cr&#62; pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
362     \&#60;lf&#62; pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
363     \&#60;crlf&#62; pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
364 nigel 93 \&#60;any&#62; pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
365 nigel 75 </pre>
366 nigel 93 The escapes that specify line ending sequences are literal strings, exactly as
367     shown. No more than one newline setting should be present in any data line.
368 nigel 63 </P>
369     <P>
370 nigel 93 A backslash followed by anything else just escapes the anything else. If
371     the very last character is a backslash, it is ignored. This gives a way of
372     passing an empty line as data, since a real empty line terminates the data
373     input.
374     </P>
375     <P>
376 nigel 63 If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
377 nigel 87 different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
378     fields of the <b>pcre_extra</b> data structure, until it finds the minimum
379     numbers for each parameter that allow <b>pcre_exec()</b> to complete. The
380     <i>match_limit</i> number is a measure of the amount of backtracking that takes
381     place, and checking it out can be instructive. For most simple matches, the
382     number is quite small, but for patterns with very large numbers of matching
383     possibilities, it can become large very quickly with increasing length of
384     subject string. The <i>match_limit_recursion</i> number is a measure of how much
385     stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed
386     to complete the match attempt.
387 nigel 63 </P>
388     <P>
389 nigel 75 When \O is used, the value specified may be higher or lower than the size set
390     by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
391     the call of <b>pcre_exec()</b> for the line in which it appears.
392 nigel 63 </P>
393     <P>
394 nigel 75 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
395 nigel 87 API to be used, the only option-setting sequences that have any effect are \B
396     and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to
397     <b>regexec()</b>.
398 nigel 63 </P>
399     <P>
400     The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
401     of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
402     any number of hexadecimal digits inside the braces. The result is from one to
403     six bytes, encoded according to the UTF-8 rules.
404     </P>
405 nigel 77 <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
406 nigel 63 <P>
407 nigel 77 By default, <b>pcretest</b> uses the standard PCRE matching function,
408     <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
409     alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
410     different way, and has some restrictions. The differences between the two
411     functions are described in the
412     <a href="pcrematching.html"><b>pcrematching</b></a>
413     documentation.
414     </P>
415     <P>
416     If a data line contains the \D escape sequence, or if the command line
417     contains the <b>-dfa</b> option, the alternative matching function is called.
418     This function finds all possible matches at a given point. If, however, the \F
419     escape sequence is present in the data line, it stops after the first match is
420     found. This is always the shortest possible match.
421     </P>
422     <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
423     <P>
424     This section describes the output when the normal matching function,
425     <b>pcre_exec()</b>, is being used.
426     </P>
427     <P>
428 nigel 63 When a match succeeds, pcretest outputs the list of captured substrings that
429     <b>pcre_exec()</b> returns, starting with number 0 for the string that matched
430 nigel 75 the whole pattern. Otherwise, it outputs "No match" or "Partial match"
431     when <b>pcre_exec()</b> returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PARTIAL,
432     respectively, and otherwise the PCRE negative error number. Here is an example
433 nigel 77 of an interactive <b>pcretest</b> run.
434 nigel 63 <pre>
435     $ pcretest
436 nigel 93 PCRE version 7.0 30-Nov-2006
437 nigel 75
438 nigel 63 re&#62; /^abc(\d+)/
439     data&#62; abc123
440     0: abc123
441     1: 123
442     data&#62; xyz
443     No match
444 nigel 75 </pre>
445 nigel 63 If the strings contain any non-printing characters, they are output as \0x
446     escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
447 nigel 93 pattern. See below for the definition of non-printing characters. If the
448     pattern has the <b>/+</b> modifier, the output for substring 0 is followed by
449     the the rest of the subject string, identified by "0+" like this:
450 nigel 63 <pre>
451     re&#62; /cat/+
452     data&#62; cataract
453     0: cat
454     0+ aract
455 nigel 75 </pre>
456 nigel 63 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
457     matching attempts are output in sequence, like this:
458     <pre>
459     re&#62; /\Bi(\w\w)/g
460     data&#62; Mississippi
461     0: iss
462     1: ss
463     0: iss
464     1: ss
465     0: ipp
466     1: pp
467 nigel 75 </pre>
468 nigel 63 "No match" is output only if the first match attempt fails.
469     </P>
470     <P>
471     If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
472     data line that is successfully matched, the substrings extracted by the
473     convenience functions are output with C, G, or L after the string number
474     instead of a colon. This is in addition to the normal full list. The string
475     length (that is, the return from the extraction function) is given in
476     parentheses after each string for <b>\C</b> and <b>\G</b>.
477     </P>
478     <P>
479 nigel 93 Note that whereas patterns can be continued over several lines (a plain "&#62;"
480 nigel 63 prompt is used for continuations), data lines may not. However newlines can be
481 nigel 93 included in data by means of the \n escape (or \r, \r\n, etc., depending on
482     the newline sequence setting).
483 nigel 63 </P>
484 nigel 77 <br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
485 nigel 63 <P>
486 nigel 77 When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
487     means of the \D escape sequence or the <b>-dfa</b> command line option), the
488     output consists of a list of all the matches that start at the first point in
489     the subject where there is at least one match. For example:
490     <pre>
491     re&#62; /(tang|tangerine|tan)/
492     data&#62; yellow tangerine\D
493     0: tangerine
494     1: tang
495     2: tan
496     </pre>
497     (Using the normal matching function on this data finds only "tang".) The
498     longest matching string is always given first (and numbered zero).
499     </P>
500     <P>
501 nigel 93 If <b>/g</b> is present on the pattern, the search for further matches resumes
502 nigel 77 at the end of the longest match. For example:
503     <pre>
504     re&#62; /(tang|tangerine|tan)/g
505     data&#62; yellow tangerine and tangy sultana\D
506     0: tangerine
507     1: tang
508     2: tan
509     0: tang
510     1: tan
511     0: tan
512     </pre>
513     Since the matching function does not support substring capture, the escape
514     sequences that are concerned with captured substrings are not relevant.
515     </P>
516     <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
517     <P>
518     When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
519     indicating that the subject partially matched the pattern, you can restart the
520     match with additional subject data by means of the \R escape sequence. For
521     example:
522     <pre>
523     re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
524     data&#62; 23ja\P\D
525     Partial match: 23ja
526     data&#62; n05\R\D
527     0: n05
528     </pre>
529     For further information about partial matching, see the
530     <a href="pcrepartial.html"><b>pcrepartial</b></a>
531     documentation.
532     </P>
533     <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
534     <P>
535 nigel 75 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
536 nigel 77 is called during matching. This works with both matching functions. By default,
537     the called function displays the callout number, the start and current
538     positions in the text at the callout time, and the next pattern item to be
539     tested. For example, the output
540 nigel 75 <pre>
541     ---&#62;pqrabcdef
542     0 ^ ^ \d
543     </pre>
544     indicates that callout number 0 occurred for a match attempt starting at the
545     fourth character of the subject string, when the pointer was at the seventh
546     character of the data, and when the next pattern item was \d. Just one
547     circumflex is output if the start and current positions are the same.
548     </P>
549     <P>
550     Callouts numbered 255 are assumed to be automatic callouts, inserted as a
551     result of the <b>/C</b> pattern modifier. In this case, instead of showing the
552     callout number, the offset in the pattern, preceded by a plus, is output. For
553     example:
554     <pre>
555     re&#62; /\d?[A-E]\*/C
556     data&#62; E*
557     ---&#62;E*
558     +0 ^ \d?
559     +3 ^ [A-E]
560     +8 ^^ \*
561     +10 ^ ^
562     0: E*
563     </pre>
564     The callout function in <b>pcretest</b> returns zero (carry on matching) by
565 nigel 77 default, but you can use a \C item in a data line (as described above) to
566 nigel 75 change this.
567     </P>
568     <P>
569     Inserting callouts can be helpful when using <b>pcretest</b> to check
570     complicated regular expressions. For further information about callouts, see
571     the
572     <a href="pcrecallout.html"><b>pcrecallout</b></a>
573     documentation.
574     </P>
575 nigel 93 <br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
576 nigel 75 <P>
577 nigel 93 When <b>pcretest</b> is outputting text in the compiled version of a pattern,
578     bytes other than 32-126 are always treated as non-printing characters are are
579     therefore shown as hex escapes.
580     </P>
581     <P>
582     When <b>pcretest</b> is outputting text that is a matched part of a subject
583     string, it behaves in the same way, unless a different locale has been set for
584     the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
585     function to distinguish printing and non-printing characters.
586     </P>
587     <br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
588     <P>
589 nigel 75 The facilities described in this section are not available when the POSIX
590     inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
591     specified.
592     </P>
593     <P>
594     When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
595     compiled pattern to a file, by following the modifiers with &#62; and a file name.
596     For example:
597     <pre>
598     /pattern/im &#62;/some/file
599     </pre>
600     See the
601     <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
602     documentation for a discussion about saving and re-using compiled patterns.
603     </P>
604     <P>
605     The data that is written is binary. The first eight bytes are the length of the
606     compiled pattern data followed by the length of the optional study data, each
607     written as four bytes in big-endian order (most significant byte first). If
608     there is no study data (either the pattern was not studied, or studying did not
609     return any data), the second length is zero. The lengths are followed by an
610     exact copy of the compiled pattern. If there is additional study data, this
611     follows immediately after the compiled pattern. After writing the file,
612     <b>pcretest</b> expects to read a new pattern.
613     </P>
614     <P>
615     A saved pattern can be reloaded into <b>pcretest</b> by specifing &#60; and a file
616     name instead of a pattern. The name of the file must not contain a &#60; character,
617     as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by &#60;
618     characters.
619     For example:
620     <pre>
621     re&#62; &#60;/some/file
622     Compiled regex loaded from /some/file
623     No study data
624     </pre>
625     When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in
626     the usual way.
627     </P>
628     <P>
629     You can copy a file written by <b>pcretest</b> to a different host and reload it
630     there, even if the new host has opposite endianness to the one on which the
631     pattern was compiled. For example, you can compile on an i86 machine and run on
632     a SPARC machine.
633     </P>
634     <P>
635     File names for saving and reloading can be absolute or relative, but note that
636     the shell facility of expanding a file name that starts with a tilde (~) is not
637     available.
638     </P>
639     <P>
640     The ability to save and reload files in <b>pcretest</b> is intended for testing
641     and experimentation. It is not intended for production use because only a
642     single pattern can be written to a file. Furthermore, there is no facility for
643     supplying custom character tables for use with a reloaded pattern. If the
644     original pattern was compiled with custom tables, an attempt to match a subject
645     string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
646     Finally, if you attempt to load a file that is not in the correct format, the
647     result is undefined.
648     </P>
649 nigel 93 <br><a name="SEC13" href="#TOC1">SEE ALSO</a><br>
650 nigel 75 <P>
651 nigel 93 <b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3),
652     <b>pcrepartial</b>(d), \fPpcrepattern\fP(3), <b>pcreprecompile</b>(3).
653     </P>
654     <br><a name="SEC14" href="#TOC1">AUTHOR</a><br>
655     <P>
656 nigel 77 Philip Hazel
657 nigel 63 <br>
658 ph10 99 University Computing Service
659 nigel 63 <br>
660 nigel 93 Cambridge CB2 3QH, England.
661 ph10 99 <br>
662 nigel 63 </P>
663 ph10 99 <br><a name="SEC15" href="#TOC1">REVISION</a><br>
664 nigel 63 <P>
665 ph10 99 Last updated: 06 March 2007
666 nigel 63 <br>
667 ph10 99 Copyright &copy; 1997-2007 University of Cambridge.
668     <br>
669 nigel 75 <p>
670     Return to the <a href="index.html">PCRE index page</a>.
671     </p>


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