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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 ph10 392 <b>-M</b>
81     Behave as if each data line contains the \M escape sequence; this causes
82     PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by
83     calling <b>pcre_exec()</b> repeatedly with different limits.
84     </P>
85     <P>
86 nigel 63 <b>-m</b>
87     Output the size of each compiled pattern after it has been compiled. This is
88 nigel 75 equivalent to adding <b>/M</b> to each regular expression. For compatibility
89     with earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>.
90 nigel 63 </P>
91     <P>
92     <b>-o</b> <i>osize</i>
93 nigel 75 Set the number of elements in the output vector that is used when calling
94 nigel 93 <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> to be <i>osize</i>. The default value
95     is 45, which is enough for 14 capturing subexpressions for <b>pcre_exec()</b> or
96     22 different matches for <b>pcre_dfa_exec()</b>. The vector size can be
97     changed for individual matching calls by including \O in the data line (see
98     below).
99 nigel 63 </P>
100     <P>
101     <b>-p</b>
102 nigel 77 Behave as if each regex has the <b>/P</b> modifier; the POSIX wrapper API is
103     used to call PCRE. None of the other options has any effect when <b>-p</b> is
104     set.
105 nigel 63 </P>
106     <P>
107 nigel 91 <b>-q</b>
108 nigel 87 Do not output the version number of <b>pcretest</b> at the start of execution.
109     </P>
110     <P>
111 nigel 91 <b>-S</b> <i>size</i>
112     On Unix-like systems, set the size of the runtime stack to <i>size</i>
113     megabytes.
114     </P>
115     <P>
116 nigel 63 <b>-t</b>
117     Run each compile, study, and match many times with a timer, and output
118 nigel 75 resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with
119     <b>-t</b>, because you will then get the size output a zillion times, and the
120 nigel 93 timing will be distorted. You can control the number of iterations that are
121     used for timing by following <b>-t</b> with a number (as a separate item on the
122     command line). For example, "-t 1000" would iterate 1000 times. The default is
123     to iterate 500000 times.
124 nigel 63 </P>
125 nigel 93 <P>
126     <b>-tm</b>
127     This is like <b>-t</b> except that it times only the matching phase, not the
128     compile or study phases.
129     </P>
130 nigel 63 <br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br>
131     <P>
132     If <b>pcretest</b> is given two filename arguments, it reads from the first and
133     writes to the second. If it is given only one filename argument, it reads from
134     that file and writes to stdout. Otherwise, it reads from stdin and writes to
135     stdout, and prompts for each line of input, using "re&#62;" to prompt for regular
136     expressions, and "data&#62;" to prompt for data lines.
137     </P>
138     <P>
139 ph10 289 When <b>pcretest</b> is built, a configuration option can specify that it should
140     be linked with the <b>libreadline</b> library. When this is done, if the input
141     is from a terminal, it is read using the <b>readline()</b> function. This
142     provides line-editing and history facilities. The output from the <b>-help</b>
143     option states whether or not <b>readline()</b> will be used.
144     </P>
145     <P>
146 nigel 63 The program handles any number of sets of input on a single input file. Each
147     set starts with a regular expression, and continues with any number of data
148     lines to be matched against the pattern.
149     </P>
150     <P>
151 nigel 75 Each data line is matched separately and independently. If you want to do
152 nigel 91 multi-line matches, you have to use the \n escape sequence (or \r or \r\n,
153 nigel 93 etc., depending on the newline setting) in a single line of input to encode the
154     newline sequences. There is no limit on the length of data lines; the input
155 nigel 91 buffer is automatically extended if it is too small.
156 nigel 63 </P>
157     <P>
158     An empty line signals the end of the data lines, at which point a new regular
159     expression is read. The regular expressions are given enclosed in any
160 nigel 91 non-alphanumeric delimiters other than backslash, for example:
161 nigel 63 <pre>
162     /(a|bc)x+yz/
163 nigel 75 </pre>
164 nigel 63 White space before the initial delimiter is ignored. A regular expression may
165     be continued over several input lines, in which case the newline characters are
166     included within it. It is possible to include the delimiter within the pattern
167     by escaping it, for example
168     <pre>
169     /abc\/def/
170 nigel 75 </pre>
171 nigel 63 If you do so, the escape and the delimiter form part of the pattern, but since
172 nigel 75 delimiters are always non-alphanumeric, this does not affect its interpretation.
173 nigel 63 If the terminating delimiter is immediately followed by a backslash, for
174     example,
175     <pre>
176     /abc/\
177 nigel 75 </pre>
178 nigel 63 then a backslash is added to the end of the pattern. This is done to provide a
179     way of testing the error condition that arises if a pattern finishes with a
180     backslash, because
181     <pre>
182     /abc\/
183 nigel 75 </pre>
184 nigel 63 is interpreted as the first line of a pattern that starts with "abc/", causing
185     pcretest to read the next line as a continuation of the regular expression.
186     </P>
187     <br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br>
188     <P>
189 nigel 75 A pattern may be followed by any number of modifiers, which are mostly single
190     characters. Following Perl usage, these are referred to below as, for example,
191     "the <b>/i</b> modifier", even though the delimiter of the pattern need not
192     always be a slash, and no slash is used when writing modifiers. Whitespace may
193     appear between the final pattern delimiter and the first modifier, and between
194     the modifiers themselves.
195 nigel 63 </P>
196     <P>
197 nigel 75 The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
198     PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
199     <b>pcre_compile()</b> is called. These four modifier letters have the same
200     effect as they do in Perl. For example:
201 nigel 63 <pre>
202     /caseless/i
203 nigel 75 </pre>
204     The following table shows additional modifiers for setting PCRE options that do
205     not correspond to anything in Perl:
206     <pre>
207 ph10 231 <b>/A</b> PCRE_ANCHORED
208     <b>/C</b> PCRE_AUTO_CALLOUT
209     <b>/E</b> PCRE_DOLLAR_ENDONLY
210     <b>/f</b> PCRE_FIRSTLINE
211     <b>/J</b> PCRE_DUPNAMES
212     <b>/N</b> PCRE_NO_AUTO_CAPTURE
213     <b>/U</b> PCRE_UNGREEDY
214     <b>/X</b> PCRE_EXTRA
215 ph10 345 <b>/&#60;JS&#62;</b> PCRE_JAVASCRIPT_COMPAT
216 ph10 231 <b>/&#60;cr&#62;</b> PCRE_NEWLINE_CR
217     <b>/&#60;lf&#62;</b> PCRE_NEWLINE_LF
218     <b>/&#60;crlf&#62;</b> PCRE_NEWLINE_CRLF
219     <b>/&#60;anycrlf&#62;</b> PCRE_NEWLINE_ANYCRLF
220     <b>/&#60;any&#62;</b> PCRE_NEWLINE_ANY
221     <b>/&#60;bsr_anycrlf&#62;</b> PCRE_BSR_ANYCRLF
222     <b>/&#60;bsr_unicode&#62;</b> PCRE_BSR_UNICODE
223 nigel 75 </pre>
224 ph10 227 Those specifying line ending sequences are literal strings as shown, but the
225     letters can be in either case. This example sets multiline matching with CRLF
226     as the line ending sequence:
227 nigel 93 <pre>
228     /^abc/m&#60;crlf&#62;
229     </pre>
230     Details of the meanings of these PCRE options are given in the
231 nigel 91 <a href="pcreapi.html"><b>pcreapi</b></a>
232     documentation.
233     </P>
234     <br><b>
235     Finding all matches in a string
236     </b><br>
237     <P>
238 nigel 63 Searching for all possible matches within each subject string can be requested
239     by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
240     again to search the remainder of the subject string. The difference between
241     <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
242     <b>pcre_exec()</b> to start searching at a new point within the entire string
243     (which is in effect what Perl does), whereas the latter passes over a shortened
244     substring. This makes a difference to the matching process if the pattern
245     begins with a lookbehind assertion (including \b or \B).
246     </P>
247     <P>
248     If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an
249 ph10 453 empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
250     PCRE_ANCHORED flags set in order to search for another, non-empty, match at the
251 ph10 461 same point. If this second match fails, the start offset is advanced by one
252 ph10 453 character, and the normal match is retried. This imitates the way Perl handles
253     such cases when using the <b>/g</b> modifier or the <b>split()</b> function.
254 nigel 63 </P>
255 nigel 91 <br><b>
256     Other modifiers
257     </b><br>
258 nigel 63 <P>
259 nigel 75 There are yet more modifiers for controlling the way <b>pcretest</b>
260 nigel 63 operates.
261     </P>
262     <P>
263     The <b>/+</b> modifier requests that as well as outputting the substring that
264     matched the entire pattern, pcretest should in addition output the remainder of
265     the subject string. This is useful for tests where the subject contains
266     multiple copies of the same substring.
267     </P>
268     <P>
269 nigel 93 The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
270 ph10 123 output a representation of the compiled byte code after compilation. Normally
271     this information contains length and offset values; however, if <b>/Z</b> is
272     also present, this data is replaced by spaces. This is a special feature for
273     use in the automatic test scripts; it ensures that the same output is generated
274     for different internal link sizes.
275 nigel 93 </P>
276     <P>
277 nigel 63 The <b>/L</b> modifier must be followed directly by the name of a locale, for
278     example,
279     <pre>
280 nigel 75 /pattern/Lfr_FR
281     </pre>
282     For this reason, it must be the last modifier. The given locale is set,
283 nigel 63 <b>pcre_maketables()</b> is called to build a set of character tables for the
284     locale, and this is then passed to <b>pcre_compile()</b> when compiling the
285     regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables
286     pointer; that is, <b>/L</b> applies only to the expression on which it appears.
287     </P>
288     <P>
289     The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
290 nigel 75 compiled pattern (whether it is anchored, has a fixed first character, and
291     so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
292     pattern. If the pattern is studied, the results of that are also output.
293 nigel 63 </P>
294     <P>
295 nigel 93 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
296 ph10 148 <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
297 nigel 63 </P>
298     <P>
299 nigel 75 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
300     fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
301     facility is for testing the feature in PCRE that allows it to execute patterns
302     that were compiled on a host with a different endianness. This feature is not
303     available when the POSIX interface to PCRE is being used, that is, when the
304     <b>/P</b> pattern modifier is specified. See also the section about saving and
305     reloading compiled patterns below.
306     </P>
307     <P>
308 nigel 63 The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the
309     expression has been compiled, and the results used when the expression is
310     matched.
311     </P>
312     <P>
313     The <b>/M</b> modifier causes the size of memory block used to hold the compiled
314     pattern to be output.
315     </P>
316     <P>
317     The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
318     API rather than its native API. When this is done, all other modifiers except
319     <b>/i</b>, <b>/m</b>, and <b>/+</b> are ignored. REG_ICASE is set if <b>/i</b> is
320     present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions
321     force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
322     </P>
323     <P>
324     The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8
325     option set. This turns on support for UTF-8 character handling in PCRE,
326     provided that it was compiled with this support enabled. This modifier also
327     causes any non-printing characters in output strings to be printed using the
328     \x{hh...} notation if they are valid UTF-8 sequences.
329     </P>
330 nigel 71 <P>
331     If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to
332     call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the
333     checking of the string for UTF-8 validity.
334     </P>
335 nigel 75 <br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
336 nigel 63 <P>
337     Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
338     whitespace is removed, and it is then scanned for \ escapes. Some of these are
339     pretty esoteric features, intended for checking out some of the more
340     complicated features of PCRE. If you are just testing "ordinary" regular
341     expressions, you probably don't need any of these. The following escapes are
342     recognized:
343     <pre>
344 nigel 93 \a alarm (BEL, \x07)
345     \b backspace (\x08)
346     \e escape (\x27)
347     \f formfeed (\x0c)
348     \n newline (\x0a)
349 nigel 91 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
350 nigel 93 \r carriage return (\x0d)
351     \t tab (\x09)
352     \v vertical tab (\x0b)
353 nigel 63 \nnn octal character (up to 3 octal digits)
354     \xhh hexadecimal character (up to 2 hex digits)
355 nigel 75 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode
356 nigel 91 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
357     \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
358 nigel 75 \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32)
359     \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
360 nigel 63 ated by next non alphanumeric character)
361 nigel 75 \C+ show the current captured substrings at callout time
362 nigel 63 \C- do not supply a callout function
363 nigel 75 \C!n return 1 instead of 0 when callout number n is reached
364     \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
365     \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
366 nigel 77 \D use the <b>pcre_dfa_exec()</b> match function
367     \F only shortest match for <b>pcre_dfa_exec()</b>
368 nigel 75 \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32)
369     \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin-
370 nigel 63 ated by next non-alphanumeric character)
371 nigel 75 \L call pcre_get_substringlist() after a successful match
372 nigel 91 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
373 ph10 453 \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the
374 ph10 461 PCRE_NOTEMPTY_ATSTART option
375 nigel 75 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
376 ph10 429 \P pass the PCRE_PARTIAL_SOFT option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the
377 ph10 461 PCRE_PARTIAL_HARD option
378 nigel 91 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
379 nigel 77 \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
380 nigel 73 \S output details of memory get/free calls during matching
381 ph10 461 \Y pass the PCRE_NO_START_OPTIMIZE option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
382 nigel 91 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
383     \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
384 nigel 75 \&#62;dd start the match at offset dd (any number of digits);
385 nigel 91 this sets the <i>startoffset</i> argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
386     \&#60;cr&#62; pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
387     \&#60;lf&#62; pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
388     \&#60;crlf&#62; pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
389 ph10 150 \&#60;anycrlf&#62; pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
390 nigel 93 \&#60;any&#62; pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
391 nigel 75 </pre>
392 nigel 93 The escapes that specify line ending sequences are literal strings, exactly as
393     shown. No more than one newline setting should be present in any data line.
394 nigel 63 </P>
395     <P>
396 nigel 93 A backslash followed by anything else just escapes the anything else. If
397     the very last character is a backslash, it is ignored. This gives a way of
398     passing an empty line as data, since a real empty line terminates the data
399     input.
400     </P>
401     <P>
402 nigel 63 If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
403 nigel 87 different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
404     fields of the <b>pcre_extra</b> data structure, until it finds the minimum
405     numbers for each parameter that allow <b>pcre_exec()</b> to complete. The
406     <i>match_limit</i> number is a measure of the amount of backtracking that takes
407     place, and checking it out can be instructive. For most simple matches, the
408     number is quite small, but for patterns with very large numbers of matching
409     possibilities, it can become large very quickly with increasing length of
410     subject string. The <i>match_limit_recursion</i> number is a measure of how much
411     stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed
412     to complete the match attempt.
413 nigel 63 </P>
414     <P>
415 nigel 75 When \O is used, the value specified may be higher or lower than the size set
416     by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
417     the call of <b>pcre_exec()</b> for the line in which it appears.
418 nigel 63 </P>
419     <P>
420 nigel 75 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
421 nigel 87 API to be used, the only option-setting sequences that have any effect are \B
422     and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to
423     <b>regexec()</b>.
424 nigel 63 </P>
425     <P>
426     The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
427     of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
428     any number of hexadecimal digits inside the braces. The result is from one to
429 ph10 211 six bytes, encoded according to the original UTF-8 rules of RFC 2279. This
430     allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are
431     valid Unicode code points, or indeed valid UTF-8 characters according to the
432     later rules in RFC 3629.
433 nigel 63 </P>
434 nigel 77 <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
435 nigel 63 <P>
436 nigel 77 By default, <b>pcretest</b> uses the standard PCRE matching function,
437     <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
438     alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
439     different way, and has some restrictions. The differences between the two
440     functions are described in the
441     <a href="pcrematching.html"><b>pcrematching</b></a>
442     documentation.
443     </P>
444     <P>
445     If a data line contains the \D escape sequence, or if the command line
446     contains the <b>-dfa</b> option, the alternative matching function is called.
447     This function finds all possible matches at a given point. If, however, the \F
448     escape sequence is present in the data line, it stops after the first match is
449     found. This is always the shortest possible match.
450     </P>
451     <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
452     <P>
453     This section describes the output when the normal matching function,
454     <b>pcre_exec()</b>, is being used.
455     </P>
456     <P>
457 nigel 63 When a match succeeds, pcretest outputs the list of captured substrings that
458     <b>pcre_exec()</b> returns, starting with number 0 for the string that matched
459 ph10 453 the whole pattern. Otherwise, it outputs "No match" when the return is
460     PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
461     substring when <b>pcre_exec()</b> returns PCRE_ERROR_PARTIAL. For any other
462     returns, it outputs the PCRE negative error number. Here is an example of an
463     interactive <b>pcretest</b> run.
464 nigel 63 <pre>
465     $ pcretest
466 nigel 93 PCRE version 7.0 30-Nov-2006
467 nigel 75
468 nigel 63 re&#62; /^abc(\d+)/
469     data&#62; abc123
470     0: abc123
471     1: 123
472     data&#62; xyz
473     No match
474 nigel 75 </pre>
475 ph10 286 Note that unset capturing substrings that are not followed by one that is set
476     are not returned by <b>pcre_exec()</b>, and are not shown by <b>pcretest</b>. In
477     the following example, there are two capturing substrings, but when the first
478     data line is matched, the second, unset substring is not shown. An "internal"
479     unset substring is shown as "&#60;unset&#62;", as for the second data line.
480     <pre>
481     re&#62; /(a)|(b)/
482     data&#62; a
483     0: a
484     1: a
485     data&#62; b
486     0: b
487     1: &#60;unset&#62;
488     2: b
489     </pre>
490 nigel 63 If the strings contain any non-printing characters, they are output as \0x
491     escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
492 nigel 93 pattern. See below for the definition of non-printing characters. If the
493     pattern has the <b>/+</b> modifier, the output for substring 0 is followed by
494     the the rest of the subject string, identified by "0+" like this:
495 nigel 63 <pre>
496     re&#62; /cat/+
497     data&#62; cataract
498     0: cat
499     0+ aract
500 nigel 75 </pre>
501 nigel 63 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
502     matching attempts are output in sequence, like this:
503     <pre>
504     re&#62; /\Bi(\w\w)/g
505     data&#62; Mississippi
506     0: iss
507     1: ss
508     0: iss
509     1: ss
510     0: ipp
511     1: pp
512 nigel 75 </pre>
513 nigel 63 "No match" is output only if the first match attempt fails.
514     </P>
515     <P>
516     If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
517     data line that is successfully matched, the substrings extracted by the
518     convenience functions are output with C, G, or L after the string number
519     instead of a colon. This is in addition to the normal full list. The string
520     length (that is, the return from the extraction function) is given in
521     parentheses after each string for <b>\C</b> and <b>\G</b>.
522     </P>
523     <P>
524 nigel 93 Note that whereas patterns can be continued over several lines (a plain "&#62;"
525 nigel 63 prompt is used for continuations), data lines may not. However newlines can be
526 nigel 93 included in data by means of the \n escape (or \r, \r\n, etc., depending on
527     the newline sequence setting).
528 nigel 63 </P>
529 nigel 77 <br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
530 nigel 63 <P>
531 nigel 77 When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
532     means of the \D escape sequence or the <b>-dfa</b> command line option), the
533     output consists of a list of all the matches that start at the first point in
534     the subject where there is at least one match. For example:
535     <pre>
536     re&#62; /(tang|tangerine|tan)/
537     data&#62; yellow tangerine\D
538     0: tangerine
539     1: tang
540     2: tan
541     </pre>
542     (Using the normal matching function on this data finds only "tang".) The
543 ph10 429 longest matching string is always given first (and numbered zero). After a
544 ph10 461 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
545 ph10 429 partially matching substring.
546 nigel 77 </P>
547     <P>
548 nigel 93 If <b>/g</b> is present on the pattern, the search for further matches resumes
549 nigel 77 at the end of the longest match. For example:
550     <pre>
551     re&#62; /(tang|tangerine|tan)/g
552     data&#62; yellow tangerine and tangy sultana\D
553     0: tangerine
554     1: tang
555     2: tan
556     0: tang
557     1: tan
558     0: tan
559     </pre>
560     Since the matching function does not support substring capture, the escape
561     sequences that are concerned with captured substrings are not relevant.
562     </P>
563     <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
564     <P>
565     When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
566     indicating that the subject partially matched the pattern, you can restart the
567     match with additional subject data by means of the \R escape sequence. For
568     example:
569     <pre>
570     re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
571     data&#62; 23ja\P\D
572     Partial match: 23ja
573     data&#62; n05\R\D
574     0: n05
575     </pre>
576     For further information about partial matching, see the
577     <a href="pcrepartial.html"><b>pcrepartial</b></a>
578     documentation.
579     </P>
580     <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
581     <P>
582 nigel 75 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
583 nigel 77 is called during matching. This works with both matching functions. By default,
584     the called function displays the callout number, the start and current
585     positions in the text at the callout time, and the next pattern item to be
586     tested. For example, the output
587 nigel 75 <pre>
588     ---&#62;pqrabcdef
589     0 ^ ^ \d
590     </pre>
591     indicates that callout number 0 occurred for a match attempt starting at the
592     fourth character of the subject string, when the pointer was at the seventh
593     character of the data, and when the next pattern item was \d. Just one
594     circumflex is output if the start and current positions are the same.
595     </P>
596     <P>
597     Callouts numbered 255 are assumed to be automatic callouts, inserted as a
598     result of the <b>/C</b> pattern modifier. In this case, instead of showing the
599     callout number, the offset in the pattern, preceded by a plus, is output. For
600     example:
601     <pre>
602     re&#62; /\d?[A-E]\*/C
603     data&#62; E*
604     ---&#62;E*
605     +0 ^ \d?
606     +3 ^ [A-E]
607     +8 ^^ \*
608     +10 ^ ^
609     0: E*
610     </pre>
611     The callout function in <b>pcretest</b> returns zero (carry on matching) by
612 nigel 77 default, but you can use a \C item in a data line (as described above) to
613 nigel 75 change this.
614     </P>
615     <P>
616     Inserting callouts can be helpful when using <b>pcretest</b> to check
617     complicated regular expressions. For further information about callouts, see
618     the
619     <a href="pcrecallout.html"><b>pcrecallout</b></a>
620     documentation.
621     </P>
622 nigel 93 <br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
623 nigel 75 <P>
624 nigel 93 When <b>pcretest</b> is outputting text in the compiled version of a pattern,
625     bytes other than 32-126 are always treated as non-printing characters are are
626     therefore shown as hex escapes.
627     </P>
628     <P>
629     When <b>pcretest</b> is outputting text that is a matched part of a subject
630     string, it behaves in the same way, unless a different locale has been set for
631     the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
632     function to distinguish printing and non-printing characters.
633     </P>
634     <br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
635     <P>
636 nigel 75 The facilities described in this section are not available when the POSIX
637     inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
638     specified.
639     </P>
640     <P>
641     When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
642     compiled pattern to a file, by following the modifiers with &#62; and a file name.
643     For example:
644     <pre>
645     /pattern/im &#62;/some/file
646     </pre>
647     See the
648     <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
649     documentation for a discussion about saving and re-using compiled patterns.
650     </P>
651     <P>
652     The data that is written is binary. The first eight bytes are the length of the
653     compiled pattern data followed by the length of the optional study data, each
654     written as four bytes in big-endian order (most significant byte first). If
655     there is no study data (either the pattern was not studied, or studying did not
656     return any data), the second length is zero. The lengths are followed by an
657     exact copy of the compiled pattern. If there is additional study data, this
658     follows immediately after the compiled pattern. After writing the file,
659     <b>pcretest</b> expects to read a new pattern.
660     </P>
661     <P>
662     A saved pattern can be reloaded into <b>pcretest</b> by specifing &#60; and a file
663     name instead of a pattern. The name of the file must not contain a &#60; character,
664     as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by &#60;
665     characters.
666     For example:
667     <pre>
668     re&#62; &#60;/some/file
669     Compiled regex loaded from /some/file
670     No study data
671     </pre>
672     When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in
673     the usual way.
674     </P>
675     <P>
676     You can copy a file written by <b>pcretest</b> to a different host and reload it
677     there, even if the new host has opposite endianness to the one on which the
678     pattern was compiled. For example, you can compile on an i86 machine and run on
679     a SPARC machine.
680     </P>
681     <P>
682     File names for saving and reloading can be absolute or relative, but note that
683     the shell facility of expanding a file name that starts with a tilde (~) is not
684     available.
685     </P>
686     <P>
687     The ability to save and reload files in <b>pcretest</b> is intended for testing
688     and experimentation. It is not intended for production use because only a
689     single pattern can be written to a file. Furthermore, there is no facility for
690     supplying custom character tables for use with a reloaded pattern. If the
691     original pattern was compiled with custom tables, an attempt to match a subject
692     string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
693     Finally, if you attempt to load a file that is not in the correct format, the
694     result is undefined.
695     </P>
696 nigel 93 <br><a name="SEC13" href="#TOC1">SEE ALSO</a><br>
697 nigel 75 <P>
698 nigel 93 <b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3),
699 ph10 148 <b>pcrepartial</b>(d), <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3).
700 nigel 93 </P>
701     <br><a name="SEC14" href="#TOC1">AUTHOR</a><br>
702     <P>
703 nigel 77 Philip Hazel
704 nigel 63 <br>
705 ph10 99 University Computing Service
706 nigel 63 <br>
707 nigel 93 Cambridge CB2 3QH, England.
708 ph10 99 <br>
709 nigel 63 </P>
710 ph10 99 <br><a name="SEC15" href="#TOC1">REVISION</a><br>
711 nigel 63 <P>
712 ph10 461 Last updated: 26 September 2009
713 nigel 63 <br>
714 ph10 392 Copyright &copy; 1997-2009 University of Cambridge.
715 ph10 99 <br>
716 nigel 75 <p>
717     Return to the <a href="index.html">PCRE index page</a>.
718     </p>


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