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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     <p>
11     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     <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     <li><a name="TOC11" href="#SEC11">SAVING AND RELOADING COMPILED PATTERNS</a>
27     <li><a name="TOC12" href="#SEC12">AUTHOR</a>
28 nigel 63 </ul>
29     <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
30     <P>
31 nigel 77 <b>pcretest [-C] [-d] [-dfa] [-i] [-m] [-o osize] [-p] [-t] [source]</b>
32 nigel 75 <b>[destination]</b>
33 nigel 63 </P>
34     <P>
35     <b>pcretest</b> was written as a test program for the PCRE regular expression
36     library itself, but it can also be used for experimenting with regular
37     expressions. This document describes the features of the test program; for
38     details of the regular expressions themselves, see the
39     <a href="pcrepattern.html"><b>pcrepattern</b></a>
40 nigel 75 documentation. For details of the PCRE library function calls and their
41     options, see the
42 nigel 63 <a href="pcreapi.html"><b>pcreapi</b></a>
43     documentation.
44     </P>
45     <br><a name="SEC2" href="#TOC1">OPTIONS</a><br>
46     <P>
47     <b>-C</b>
48     Output the version number of the PCRE library, and all available information
49     about the optional features that are included, and then exit.
50     </P>
51     <P>
52     <b>-d</b>
53 nigel 77 Behave as if each regex has the <b>/D</b> (debug) modifier; the internal
54 nigel 63 form is output after compilation.
55     </P>
56     <P>
57 nigel 77 <b>-dfa</b>
58     Behave as if each data line contains the \D escape sequence; this causes the
59     alternative matching function, <b>pcre_dfa_exec()</b>, to be used instead of the
60     standard <b>pcre_exec()</b> function (more detail is given below).
61     </P>
62     <P>
63 nigel 63 <b>-i</b>
64 nigel 77 Behave as if each regex has the <b>/I</b> modifier; information about the
65 nigel 63 compiled pattern is given after compilation.
66     </P>
67     <P>
68     <b>-m</b>
69     Output the size of each compiled pattern after it has been compiled. This is
70 nigel 75 equivalent to adding <b>/M</b> to each regular expression. For compatibility
71     with earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>.
72 nigel 63 </P>
73     <P>
74     <b>-o</b> <i>osize</i>
75 nigel 75 Set the number of elements in the output vector that is used when calling
76     <b>pcre_exec()</b> to be <i>osize</i>. The default value is 45, which is enough
77     for 14 capturing subexpressions. The vector size can be changed for individual
78     matching calls by including \O in the data line (see below).
79 nigel 63 </P>
80     <P>
81     <b>-p</b>
82 nigel 77 Behave as if each regex has the <b>/P</b> modifier; the POSIX wrapper API is
83     used to call PCRE. None of the other options has any effect when <b>-p</b> is
84     set.
85 nigel 63 </P>
86     <P>
87     <b>-t</b>
88     Run each compile, study, and match many times with a timer, and output
89 nigel 75 resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with
90     <b>-t</b>, because you will then get the size output a zillion times, and the
91     timing will be distorted.
92 nigel 63 </P>
93     <br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br>
94     <P>
95     If <b>pcretest</b> is given two filename arguments, it reads from the first and
96     writes to the second. If it is given only one filename argument, it reads from
97     that file and writes to stdout. Otherwise, it reads from stdin and writes to
98     stdout, and prompts for each line of input, using "re&#62;" to prompt for regular
99     expressions, and "data&#62;" to prompt for data lines.
100     </P>
101     <P>
102     The program handles any number of sets of input on a single input file. Each
103     set starts with a regular expression, and continues with any number of data
104     lines to be matched against the pattern.
105     </P>
106     <P>
107 nigel 75 Each data line is matched separately and independently. If you want to do
108 nigel 63 multiple-line matches, you have to use the \n escape sequence in a single line
109     of input to encode the newline characters. The maximum length of data line is
110     30,000 characters.
111     </P>
112     <P>
113     An empty line signals the end of the data lines, at which point a new regular
114     expression is read. The regular expressions are given enclosed in any
115 nigel 75 non-alphanumeric delimiters other than backslash, for example
116 nigel 63 <pre>
117     /(a|bc)x+yz/
118 nigel 75 </pre>
119 nigel 63 White space before the initial delimiter is ignored. A regular expression may
120     be continued over several input lines, in which case the newline characters are
121     included within it. It is possible to include the delimiter within the pattern
122     by escaping it, for example
123     <pre>
124     /abc\/def/
125 nigel 75 </pre>
126 nigel 63 If you do so, the escape and the delimiter form part of the pattern, but since
127 nigel 75 delimiters are always non-alphanumeric, this does not affect its interpretation.
128 nigel 63 If the terminating delimiter is immediately followed by a backslash, for
129     example,
130     <pre>
131     /abc/\
132 nigel 75 </pre>
133 nigel 63 then a backslash is added to the end of the pattern. This is done to provide a
134     way of testing the error condition that arises if a pattern finishes with a
135     backslash, because
136     <pre>
137     /abc\/
138 nigel 75 </pre>
139 nigel 63 is interpreted as the first line of a pattern that starts with "abc/", causing
140     pcretest to read the next line as a continuation of the regular expression.
141     </P>
142     <br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br>
143     <P>
144 nigel 75 A pattern may be followed by any number of modifiers, which are mostly single
145     characters. Following Perl usage, these are referred to below as, for example,
146     "the <b>/i</b> modifier", even though the delimiter of the pattern need not
147     always be a slash, and no slash is used when writing modifiers. Whitespace may
148     appear between the final pattern delimiter and the first modifier, and between
149     the modifiers themselves.
150 nigel 63 </P>
151     <P>
152 nigel 75 The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
153     PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
154     <b>pcre_compile()</b> is called. These four modifier letters have the same
155     effect as they do in Perl. For example:
156 nigel 63 <pre>
157     /caseless/i
158 nigel 75 </pre>
159     The following table shows additional modifiers for setting PCRE options that do
160     not correspond to anything in Perl:
161     <pre>
162     <b>/A</b> PCRE_ANCHORED
163     <b>/C</b> PCRE_AUTO_CALLOUT
164     <b>/E</b> PCRE_DOLLAR_ENDONLY
165 nigel 77 <b>/f</b> PCRE_FIRSTLINE
166 nigel 75 <b>/N</b> PCRE_NO_AUTO_CAPTURE
167     <b>/U</b> PCRE_UNGREEDY
168     <b>/X</b> PCRE_EXTRA
169     </pre>
170 nigel 63 Searching for all possible matches within each subject string can be requested
171     by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
172     again to search the remainder of the subject string. The difference between
173     <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
174     <b>pcre_exec()</b> to start searching at a new point within the entire string
175     (which is in effect what Perl does), whereas the latter passes over a shortened
176     substring. This makes a difference to the matching process if the pattern
177     begins with a lookbehind assertion (including \b or \B).
178     </P>
179     <P>
180     If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an
181     empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
182     flags set in order to search for another, non-empty, match at the same point.
183     If this second match fails, the start offset is advanced by one, and the normal
184     match is retried. This imitates the way Perl handles such cases when using the
185     <b>/g</b> modifier or the <b>split()</b> function.
186     </P>
187     <P>
188 nigel 75 There are yet more modifiers for controlling the way <b>pcretest</b>
189 nigel 63 operates.
190     </P>
191     <P>
192     The <b>/+</b> modifier requests that as well as outputting the substring that
193     matched the entire pattern, pcretest should in addition output the remainder of
194     the subject string. This is useful for tests where the subject contains
195     multiple copies of the same substring.
196     </P>
197     <P>
198     The <b>/L</b> modifier must be followed directly by the name of a locale, for
199     example,
200     <pre>
201 nigel 75 /pattern/Lfr_FR
202     </pre>
203     For this reason, it must be the last modifier. The given locale is set,
204 nigel 63 <b>pcre_maketables()</b> is called to build a set of character tables for the
205     locale, and this is then passed to <b>pcre_compile()</b> when compiling the
206     regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables
207     pointer; that is, <b>/L</b> applies only to the expression on which it appears.
208     </P>
209     <P>
210     The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
211 nigel 75 compiled pattern (whether it is anchored, has a fixed first character, and
212     so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
213     pattern. If the pattern is studied, the results of that are also output.
214 nigel 63 </P>
215     <P>
216     The <b>/D</b> modifier is a PCRE debugging feature, which also assumes <b>/I</b>.
217     It causes the internal form of compiled regular expressions to be output after
218     compilation. If the pattern was studied, the information returned is also
219     output.
220     </P>
221     <P>
222 nigel 75 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
223     fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
224     facility is for testing the feature in PCRE that allows it to execute patterns
225     that were compiled on a host with a different endianness. This feature is not
226     available when the POSIX interface to PCRE is being used, that is, when the
227     <b>/P</b> pattern modifier is specified. See also the section about saving and
228     reloading compiled patterns below.
229     </P>
230     <P>
231 nigel 63 The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the
232     expression has been compiled, and the results used when the expression is
233     matched.
234     </P>
235     <P>
236     The <b>/M</b> modifier causes the size of memory block used to hold the compiled
237     pattern to be output.
238     </P>
239     <P>
240     The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
241     API rather than its native API. When this is done, all other modifiers except
242     <b>/i</b>, <b>/m</b>, and <b>/+</b> are ignored. REG_ICASE is set if <b>/i</b> is
243     present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions
244     force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
245     </P>
246     <P>
247     The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8
248     option set. This turns on support for UTF-8 character handling in PCRE,
249     provided that it was compiled with this support enabled. This modifier also
250     causes any non-printing characters in output strings to be printed using the
251     \x{hh...} notation if they are valid UTF-8 sequences.
252     </P>
253 nigel 71 <P>
254     If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to
255     call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the
256     checking of the string for UTF-8 validity.
257     </P>
258 nigel 75 <br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
259 nigel 63 <P>
260     Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
261     whitespace is removed, and it is then scanned for \ escapes. Some of these are
262     pretty esoteric features, intended for checking out some of the more
263     complicated features of PCRE. If you are just testing "ordinary" regular
264     expressions, you probably don't need any of these. The following escapes are
265     recognized:
266     <pre>
267     \a alarm (= BEL)
268     \b backspace
269     \e escape
270     \f formfeed
271     \n newline
272     \r carriage return
273     \t tab
274     \v vertical tab
275     \nnn octal character (up to 3 octal digits)
276     \xhh hexadecimal character (up to 2 hex digits)
277 nigel 75 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode
278 nigel 63 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b>
279     \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b>
280 nigel 75 \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32)
281     \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
282 nigel 63 ated by next non alphanumeric character)
283 nigel 75 \C+ show the current captured substrings at callout time
284 nigel 63 \C- do not supply a callout function
285 nigel 75 \C!n return 1 instead of 0 when callout number n is reached
286     \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
287     \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
288 nigel 77 \D use the <b>pcre_dfa_exec()</b> match function
289     \F only shortest match for <b>pcre_dfa_exec()</b>
290 nigel 75 \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32)
291     \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin-
292 nigel 63 ated by next non-alphanumeric character)
293 nigel 75 \L call pcre_get_substringlist() after a successful match
294 nigel 63 \M discover the minimum MATCH_LIMIT setting
295     \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b>
296 nigel 75 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
297 nigel 77 \P pass the PCRE_PARTIAL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
298     \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
299 nigel 73 \S output details of memory get/free calls during matching
300 nigel 63 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b>
301 nigel 75 \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b>
302     \&#62;dd start the match at offset dd (any number of digits);
303     this sets the <i>startoffset</i> argument for <b>pcre_exec()</b>
304     </pre>
305     A backslash followed by anything else just escapes the anything else. If the
306     very last character is a backslash, it is ignored. This gives a way of passing
307     an empty line as data, since a real empty line terminates the data input.
308 nigel 63 </P>
309     <P>
310     If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
311     different values in the <i>match_limit</i> field of the <b>pcre_extra</b> data
312     structure, until it finds the minimum number that is needed for
313     <b>pcre_exec()</b> to complete. This number is a measure of the amount of
314     recursion and backtracking that takes place, and checking it out can be
315     instructive. For most simple matches, the number is quite small, but for
316     patterns with very large numbers of matching possibilities, it can become large
317     very quickly with increasing length of subject string.
318     </P>
319     <P>
320 nigel 75 When \O is used, the value specified may be higher or lower than the size set
321     by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
322     the call of <b>pcre_exec()</b> for the line in which it appears.
323 nigel 63 </P>
324     <P>
325 nigel 75 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
326     API to be used, only \B and \Z have any effect, causing REG_NOTBOL and
327     REG_NOTEOL to be passed to <b>regexec()</b> respectively.
328 nigel 63 </P>
329     <P>
330     The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
331     of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
332     any number of hexadecimal digits inside the braces. The result is from one to
333     six bytes, encoded according to the UTF-8 rules.
334     </P>
335 nigel 77 <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
336 nigel 63 <P>
337 nigel 77 By default, <b>pcretest</b> uses the standard PCRE matching function,
338     <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
339     alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
340     different way, and has some restrictions. The differences between the two
341     functions are described in the
342     <a href="pcrematching.html"><b>pcrematching</b></a>
343     documentation.
344     </P>
345     <P>
346     If a data line contains the \D escape sequence, or if the command line
347     contains the <b>-dfa</b> option, the alternative matching function is called.
348     This function finds all possible matches at a given point. If, however, the \F
349     escape sequence is present in the data line, it stops after the first match is
350     found. This is always the shortest possible match.
351     </P>
352     <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
353     <P>
354     This section describes the output when the normal matching function,
355     <b>pcre_exec()</b>, is being used.
356     </P>
357     <P>
358 nigel 63 When a match succeeds, pcretest outputs the list of captured substrings that
359     <b>pcre_exec()</b> returns, starting with number 0 for the string that matched
360 nigel 75 the whole pattern. Otherwise, it outputs "No match" or "Partial match"
361     when <b>pcre_exec()</b> returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PARTIAL,
362     respectively, and otherwise the PCRE negative error number. Here is an example
363 nigel 77 of an interactive <b>pcretest</b> run.
364 nigel 63 <pre>
365     $ pcretest
366 nigel 75 PCRE version 5.00 07-Sep-2004
367    
368 nigel 63 re&#62; /^abc(\d+)/
369     data&#62; abc123
370     0: abc123
371     1: 123
372     data&#62; xyz
373     No match
374 nigel 75 </pre>
375 nigel 63 If the strings contain any non-printing characters, they are output as \0x
376     escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
377 nigel 75 pattern. If the pattern has the <b>/+</b> modifier, the output for substring 0
378     is followed by the the rest of the subject string, identified by "0+" like
379     this:
380 nigel 63 <pre>
381     re&#62; /cat/+
382     data&#62; cataract
383     0: cat
384     0+ aract
385 nigel 75 </pre>
386 nigel 63 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
387     matching attempts are output in sequence, like this:
388     <pre>
389     re&#62; /\Bi(\w\w)/g
390     data&#62; Mississippi
391     0: iss
392     1: ss
393     0: iss
394     1: ss
395     0: ipp
396     1: pp
397 nigel 75 </pre>
398 nigel 63 "No match" is output only if the first match attempt fails.
399     </P>
400     <P>
401     If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
402     data line that is successfully matched, the substrings extracted by the
403     convenience functions are output with C, G, or L after the string number
404     instead of a colon. This is in addition to the normal full list. The string
405     length (that is, the return from the extraction function) is given in
406     parentheses after each string for <b>\C</b> and <b>\G</b>.
407     </P>
408     <P>
409     Note that while patterns can be continued over several lines (a plain "&#62;"
410     prompt is used for continuations), data lines may not. However newlines can be
411     included in data by means of the \n escape.
412     </P>
413 nigel 77 <br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
414 nigel 63 <P>
415 nigel 77 When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
416     means of the \D escape sequence or the <b>-dfa</b> command line option), the
417     output consists of a list of all the matches that start at the first point in
418     the subject where there is at least one match. For example:
419     <pre>
420     re&#62; /(tang|tangerine|tan)/
421     data&#62; yellow tangerine\D
422     0: tangerine
423     1: tang
424     2: tan
425     </pre>
426     (Using the normal matching function on this data finds only "tang".) The
427     longest matching string is always given first (and numbered zero).
428     </P>
429     <P>
430     If \fB/g\P is present on the pattern, the search for further matches resumes
431     at the end of the longest match. For example:
432     <pre>
433     re&#62; /(tang|tangerine|tan)/g
434     data&#62; yellow tangerine and tangy sultana\D
435     0: tangerine
436     1: tang
437     2: tan
438     0: tang
439     1: tan
440     0: tan
441     </pre>
442     Since the matching function does not support substring capture, the escape
443     sequences that are concerned with captured substrings are not relevant.
444     </P>
445     <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
446     <P>
447     When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
448     indicating that the subject partially matched the pattern, you can restart the
449     match with additional subject data by means of the \R escape sequence. For
450     example:
451     <pre>
452     re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
453     data&#62; 23ja\P\D
454     Partial match: 23ja
455     data&#62; n05\R\D
456     0: n05
457     </pre>
458     For further information about partial matching, see the
459     <a href="pcrepartial.html"><b>pcrepartial</b></a>
460     documentation.
461     </P>
462     <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
463     <P>
464 nigel 75 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
465 nigel 77 is called during matching. This works with both matching functions. By default,
466     the called function displays the callout number, the start and current
467     positions in the text at the callout time, and the next pattern item to be
468     tested. For example, the output
469 nigel 75 <pre>
470     ---&#62;pqrabcdef
471     0 ^ ^ \d
472     </pre>
473     indicates that callout number 0 occurred for a match attempt starting at the
474     fourth character of the subject string, when the pointer was at the seventh
475     character of the data, and when the next pattern item was \d. Just one
476     circumflex is output if the start and current positions are the same.
477     </P>
478     <P>
479     Callouts numbered 255 are assumed to be automatic callouts, inserted as a
480     result of the <b>/C</b> pattern modifier. In this case, instead of showing the
481     callout number, the offset in the pattern, preceded by a plus, is output. For
482     example:
483     <pre>
484     re&#62; /\d?[A-E]\*/C
485     data&#62; E*
486     ---&#62;E*
487     +0 ^ \d?
488     +3 ^ [A-E]
489     +8 ^^ \*
490     +10 ^ ^
491     0: E*
492     </pre>
493     The callout function in <b>pcretest</b> returns zero (carry on matching) by
494 nigel 77 default, but you can use a \C item in a data line (as described above) to
495 nigel 75 change this.
496     </P>
497     <P>
498     Inserting callouts can be helpful when using <b>pcretest</b> to check
499     complicated regular expressions. For further information about callouts, see
500     the
501     <a href="pcrecallout.html"><b>pcrecallout</b></a>
502     documentation.
503     </P>
504 nigel 77 <br><a name="SEC11" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
505 nigel 75 <P>
506     The facilities described in this section are not available when the POSIX
507     inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
508     specified.
509     </P>
510     <P>
511     When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
512     compiled pattern to a file, by following the modifiers with &#62; and a file name.
513     For example:
514     <pre>
515     /pattern/im &#62;/some/file
516     </pre>
517     See the
518     <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
519     documentation for a discussion about saving and re-using compiled patterns.
520     </P>
521     <P>
522     The data that is written is binary. The first eight bytes are the length of the
523     compiled pattern data followed by the length of the optional study data, each
524     written as four bytes in big-endian order (most significant byte first). If
525     there is no study data (either the pattern was not studied, or studying did not
526     return any data), the second length is zero. The lengths are followed by an
527     exact copy of the compiled pattern. If there is additional study data, this
528     follows immediately after the compiled pattern. After writing the file,
529     <b>pcretest</b> expects to read a new pattern.
530     </P>
531     <P>
532     A saved pattern can be reloaded into <b>pcretest</b> by specifing &#60; and a file
533     name instead of a pattern. The name of the file must not contain a &#60; character,
534     as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by &#60;
535     characters.
536     For example:
537     <pre>
538     re&#62; &#60;/some/file
539     Compiled regex loaded from /some/file
540     No study data
541     </pre>
542     When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in
543     the usual way.
544     </P>
545     <P>
546     You can copy a file written by <b>pcretest</b> to a different host and reload it
547     there, even if the new host has opposite endianness to the one on which the
548     pattern was compiled. For example, you can compile on an i86 machine and run on
549     a SPARC machine.
550     </P>
551     <P>
552     File names for saving and reloading can be absolute or relative, but note that
553     the shell facility of expanding a file name that starts with a tilde (~) is not
554     available.
555     </P>
556     <P>
557     The ability to save and reload files in <b>pcretest</b> is intended for testing
558     and experimentation. It is not intended for production use because only a
559     single pattern can be written to a file. Furthermore, there is no facility for
560     supplying custom character tables for use with a reloaded pattern. If the
561     original pattern was compiled with custom tables, an attempt to match a subject
562     string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
563     Finally, if you attempt to load a file that is not in the correct format, the
564     result is undefined.
565     </P>
566 nigel 77 <br><a name="SEC12" href="#TOC1">AUTHOR</a><br>
567 nigel 75 <P>
568 nigel 77 Philip Hazel
569 nigel 63 <br>
570     University Computing Service,
571     <br>
572     Cambridge CB2 3QG, England.
573     </P>
574     <P>
575 nigel 77 Last updated: 28 February 2005
576 nigel 63 <br>
577 nigel 77 Copyright &copy; 1997-2005 University of Cambridge.
578 nigel 75 <p>
579     Return to the <a href="index.html">PCRE index page</a>.
580     </p>

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