1<html> 2<head> 3<title>pcretest specification</title> 4</head> 5<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> 6<h1>pcretest man page</h1> 7<p> 8Return to the <a href="index.html">PCRE index page</a>. 9</p> 10<p> 11This page is part of the PCRE HTML documentation. It was generated automatically 12from the original man page. If there is any nonsense in it, please consult the 13man page, in case the conversion went wrong. 14<br> 15<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<li><a name="TOC5" href="#SEC5">DATA LINES</a> 21<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">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<li><a name="TOC15" href="#SEC15">REVISION</a> 31</ul> 32<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> 33<P> 34<b>pcretest [options] [source] [destination]</b> 35<br> 36<br> 37<b>pcretest</b> was written as a test program for the PCRE regular expression 38library itself, but it can also be used for experimenting with regular 39expressions. This document describes the features of the test program; for 40details of the regular expressions themselves, see the 41<a href="pcrepattern.html"><b>pcrepattern</b></a> 42documentation. For details of the PCRE library function calls and their 43options, see the 44<a href="pcreapi.html"><b>pcreapi</b></a> 45documentation. 46</P> 47<br><a name="SEC2" href="#TOC1">OPTIONS</a><br> 48<P> 49<b>-b</b> 50Behave as if each regex has the <b>/B</b> (show bytecode) modifier; the internal 51form is output after compilation. 52</P> 53<P> 54<b>-C</b> 55Output the version number of the PCRE library, and all available information 56about the optional features that are included, and then exit. 57</P> 58<P> 59<b>-d</b> 60Behave as if each regex has the <b>/D</b> (debug) modifier; the internal 61form and information about the compiled pattern is output after compilation; 62<b>-d</b> is equivalent to <b>-b -i</b>. 63</P> 64<P> 65<b>-dfa</b> 66Behave as if each data line contains the \D escape sequence; this causes the 67alternative matching function, <b>pcre_dfa_exec()</b>, to be used instead of the 68standard <b>pcre_exec()</b> function (more detail is given below). 69</P> 70<P> 71<b>-help</b> 72Output a brief summary these options and then exit. 73</P> 74<P> 75<b>-i</b> 76Behave as if each regex has the <b>/I</b> modifier; information about the 77compiled pattern is given after compilation. 78</P> 79<P> 80<b>-M</b> 81Behave as if each data line contains the \M escape sequence; this causes 82PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by 83calling <b>pcre_exec()</b> repeatedly with different limits. 84</P> 85<P> 86<b>-m</b> 87Output the size of each compiled pattern after it has been compiled. This is 88equivalent to adding <b>/M</b> to each regular expression. For compatibility 89with earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>. 90</P> 91<P> 92<b>-o</b> <i>osize</i> 93Set the number of elements in the output vector that is used when calling 94<b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> to be <i>osize</i>. The default value 95is 45, which is enough for 14 capturing subexpressions for <b>pcre_exec()</b> or 9622 different matches for <b>pcre_dfa_exec()</b>. The vector size can be 97changed for individual matching calls by including \O in the data line (see 98below). 99</P> 100<P> 101<b>-p</b> 102Behave as if each regex has the <b>/P</b> modifier; the POSIX wrapper API is 103used to call PCRE. None of the other options has any effect when <b>-p</b> is 104set. 105</P> 106<P> 107<b>-q</b> 108Do not output the version number of <b>pcretest</b> at the start of execution. 109</P> 110<P> 111<b>-S</b> <i>size</i> 112On Unix-like systems, set the size of the runtime stack to <i>size</i> 113megabytes. 114</P> 115<P> 116<b>-t</b> 117Run each compile, study, and match many times with a timer, and output 118resulting 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 120timing will be distorted. You can control the number of iterations that are 121used for timing by following <b>-t</b> with a number (as a separate item on the 122command line). For example, "-t 1000" would iterate 1000 times. The default is 123to iterate 500000 times. 124</P> 125<P> 126<b>-tm</b> 127This is like <b>-t</b> except that it times only the matching phase, not the 128compile or study phases. 129</P> 130<br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br> 131<P> 132If <b>pcretest</b> is given two filename arguments, it reads from the first and 133writes to the second. If it is given only one filename argument, it reads from 134that file and writes to stdout. Otherwise, it reads from stdin and writes to 135stdout, and prompts for each line of input, using "re>" to prompt for regular 136expressions, and "data>" to prompt for data lines. 137</P> 138<P> 139When <b>pcretest</b> is built, a configuration option can specify that it should 140be linked with the <b>libreadline</b> library. When this is done, if the input 141is from a terminal, it is read using the <b>readline()</b> function. This 142provides line-editing and history facilities. The output from the <b>-help</b> 143option states whether or not <b>readline()</b> will be used. 144</P> 145<P> 146The program handles any number of sets of input on a single input file. Each 147set starts with a regular expression, and continues with any number of data 148lines to be matched against the pattern. 149</P> 150<P> 151Each data line is matched separately and independently. If you want to do 152multi-line matches, you have to use the \n escape sequence (or \r or \r\n, 153etc., depending on the newline setting) in a single line of input to encode the 154newline sequences. There is no limit on the length of data lines; the input 155buffer is automatically extended if it is too small. 156</P> 157<P> 158An empty line signals the end of the data lines, at which point a new regular 159expression is read. The regular expressions are given enclosed in any 160non-alphanumeric delimiters other than backslash, for example: 161<pre> 162 /(a|bc)x+yz/ 163</pre> 164White space before the initial delimiter is ignored. A regular expression may 165be continued over several input lines, in which case the newline characters are 166included within it. It is possible to include the delimiter within the pattern 167by escaping it, for example 168<pre> 169 /abc\/def/ 170</pre> 171If you do so, the escape and the delimiter form part of the pattern, but since 172delimiters are always non-alphanumeric, this does not affect its interpretation. 173If the terminating delimiter is immediately followed by a backslash, for 174example, 175<pre> 176 /abc/\ 177</pre> 178then a backslash is added to the end of the pattern. This is done to provide a 179way of testing the error condition that arises if a pattern finishes with a 180backslash, because 181<pre> 182 /abc\/ 183</pre> 184is interpreted as the first line of a pattern that starts with "abc/", causing 185pcretest 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> 189A pattern may be followed by any number of modifiers, which are mostly single 190characters. 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 192always be a slash, and no slash is used when writing modifiers. Whitespace may 193appear between the final pattern delimiter and the first modifier, and between 194the modifiers themselves. 195</P> 196<P> 197The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS, 198PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when 199<b>pcre_compile()</b> is called. These four modifier letters have the same 200effect as they do in Perl. For example: 201<pre> 202 /caseless/i 203</pre> 204The following table shows additional modifiers for setting PCRE options that do 205not correspond to anything in Perl: 206<pre> 207 <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 <b>/<JS></b> PCRE_JAVASCRIPT_COMPAT 216 <b>/<cr></b> PCRE_NEWLINE_CR 217 <b>/<lf></b> PCRE_NEWLINE_LF 218 <b>/<crlf></b> PCRE_NEWLINE_CRLF 219 <b>/<anycrlf></b> PCRE_NEWLINE_ANYCRLF 220 <b>/<any></b> PCRE_NEWLINE_ANY 221 <b>/<bsr_anycrlf></b> PCRE_BSR_ANYCRLF 222 <b>/<bsr_unicode></b> PCRE_BSR_UNICODE 223</pre> 224Those specifying line ending sequences are literal strings as shown, but the 225letters can be in either case. This example sets multiline matching with CRLF 226as the line ending sequence: 227<pre> 228 /^abc/m<crlf> 229</pre> 230Details of the meanings of these PCRE options are given in the 231<a href="pcreapi.html"><b>pcreapi</b></a> 232documentation. 233</P> 234<br><b> 235Finding all matches in a string 236</b><br> 237<P> 238Searching for all possible matches within each subject string can be requested 239by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called 240again 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 244substring. This makes a difference to the matching process if the pattern 245begins with a lookbehind assertion (including \b or \B). 246</P> 247<P> 248If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an 249empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and 250PCRE_ANCHORED flags set in order to search for another, non-empty, match at the 251same point. If this second match fails, the start offset is advanced by one 252character, and the normal match is retried. This imitates the way Perl handles 253such cases when using the <b>/g</b> modifier or the <b>split()</b> function. 254</P> 255<br><b> 256Other modifiers 257</b><br> 258<P> 259There are yet more modifiers for controlling the way <b>pcretest</b> 260operates. 261</P> 262<P> 263The <b>/+</b> modifier requests that as well as outputting the substring that 264matched the entire pattern, pcretest should in addition output the remainder of 265the subject string. This is useful for tests where the subject contains 266multiple copies of the same substring. 267</P> 268<P> 269The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b> 270output a representation of the compiled byte code after compilation. Normally 271this information contains length and offset values; however, if <b>/Z</b> is 272also present, this data is replaced by spaces. This is a special feature for 273use in the automatic test scripts; it ensures that the same output is generated 274for different internal link sizes. 275</P> 276<P> 277The <b>/L</b> modifier must be followed directly by the name of a locale, for 278example, 279<pre> 280 /pattern/Lfr_FR 281</pre> 282For this reason, it must be the last modifier. The given locale is set, 283<b>pcre_maketables()</b> is called to build a set of character tables for the 284locale, and this is then passed to <b>pcre_compile()</b> when compiling the 285regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables 286pointer; that is, <b>/L</b> applies only to the expression on which it appears. 287</P> 288<P> 289The <b>/I</b> modifier requests that <b>pcretest</b> output information about the 290compiled pattern (whether it is anchored, has a fixed first character, and 291so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a 292pattern. If the pattern is studied, the results of that are also output. 293</P> 294<P> 295The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to 296<b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers. 297</P> 298<P> 299The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the 300fields in the compiled pattern that contain 2-byte and 4-byte numbers. This 301facility is for testing the feature in PCRE that allows it to execute patterns 302that were compiled on a host with a different endianness. This feature is not 303available 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 305reloading compiled patterns below. 306</P> 307<P> 308The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the 309expression has been compiled, and the results used when the expression is 310matched. 311</P> 312<P> 313The <b>/M</b> modifier causes the size of memory block used to hold the compiled 314pattern to be output. 315</P> 316<P> 317The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper 318API 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 320present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions 321force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set. 322</P> 323<P> 324The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8 325option set. This turns on support for UTF-8 character handling in PCRE, 326provided that it was compiled with this support enabled. This modifier also 327causes 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<P> 331If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to 332call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the 333checking of the string for UTF-8 validity. 334</P> 335<br><a name="SEC5" href="#TOC1">DATA LINES</a><br> 336<P> 337Before each data line is passed to <b>pcre_exec()</b>, leading and trailing 338whitespace is removed, and it is then scanned for \ escapes. Some of these are 339pretty esoteric features, intended for checking out some of the more 340complicated features of PCRE. If you are just testing "ordinary" regular 341expressions, you probably don't need any of these. The following escapes are 342recognized: 343<pre> 344 \a alarm (BEL, \x07) 345 \b backspace (\x08) 346 \e escape (\x27) 347 \f formfeed (\x0c) 348 \n newline (\x0a) 349 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits) 350 \r carriage return (\x0d) 351 \t tab (\x09) 352 \v vertical tab (\x0b) 353 \nnn octal character (up to 3 octal digits) 354 \xhh hexadecimal character (up to 2 hex digits) 355 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode 356 \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 \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 ated by next non alphanumeric character) 361 \C+ show the current captured substrings at callout time 362 \C- do not supply a callout function 363 \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 \D use the <b>pcre_dfa_exec()</b> match function 367 \F only shortest match for <b>pcre_dfa_exec()</b> 368 \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 ated by next non-alphanumeric character) 371 \L call pcre_get_substringlist() after a successful match 372 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings 373 \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the 374 PCRE_NOTEMPTY_ATSTART option 375 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits) 376 \P pass the PCRE_PARTIAL_SOFT option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the 377 PCRE_PARTIAL_HARD option 378 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits) 379 \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b> 380 \S output details of memory get/free calls during matching 381 \Y pass the PCRE_NO_START_OPTIMIZE option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 382 \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 \>dd start the match at offset dd (any number of digits); 385 this sets the <i>startoffset</i> argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 386 \<cr> pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 387 \<lf> pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 388 \<crlf> pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 389 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 390 \<any> pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 391</pre> 392The escapes that specify line ending sequences are literal strings, exactly as 393shown. No more than one newline setting should be present in any data line. 394</P> 395<P> 396A backslash followed by anything else just escapes the anything else. If 397the very last character is a backslash, it is ignored. This gives a way of 398passing an empty line as data, since a real empty line terminates the data 399input. 400</P> 401<P> 402If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with 403different values in the <i>match_limit</i> and <i>match_limit_recursion</i> 404fields of the <b>pcre_extra</b> data structure, until it finds the minimum 405numbers 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 407place, and checking it out can be instructive. For most simple matches, the 408number is quite small, but for patterns with very large numbers of matching 409possibilities, it can become large very quickly with increasing length of 410subject string. The <i>match_limit_recursion</i> number is a measure of how much 411stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed 412to complete the match attempt. 413</P> 414<P> 415When \O is used, the value specified may be higher or lower than the size set 416by the <b>-O</b> command line option (or defaulted to 45); \O applies only to 417the call of <b>pcre_exec()</b> for the line in which it appears. 418</P> 419<P> 420If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper 421API to be used, the only option-setting sequences that have any effect are \B 422and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to 423<b>regexec()</b>. 424</P> 425<P> 426The use of \x{hh...} to represent UTF-8 characters is not dependent on the use 427of the <b>/8</b> modifier on the pattern. It is recognized always. There may be 428any number of hexadecimal digits inside the braces. The result is from one to 429six bytes, encoded according to the original UTF-8 rules of RFC 2279. This 430allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are 431valid Unicode code points, or indeed valid UTF-8 characters according to the 432later rules in RFC 3629. 433</P> 434<br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br> 435<P> 436By 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 438alternative matching function, <b>pcre_dfa_test()</b>, which operates in a 439different way, and has some restrictions. The differences between the two 440functions are described in the 441<a href="pcrematching.html"><b>pcrematching</b></a> 442documentation. 443</P> 444<P> 445If a data line contains the \D escape sequence, or if the command line 446contains the <b>-dfa</b> option, the alternative matching function is called. 447This function finds all possible matches at a given point. If, however, the \F 448escape sequence is present in the data line, it stops after the first match is 449found. This is always the shortest possible match. 450</P> 451<br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br> 452<P> 453This section describes the output when the normal matching function, 454<b>pcre_exec()</b>, is being used. 455</P> 456<P> 457When 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 459the whole pattern. Otherwise, it outputs "No match" when the return is 460PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching 461substring when <b>pcre_exec()</b> returns PCRE_ERROR_PARTIAL. For any other 462returns, it outputs the PCRE negative error number. Here is an example of an 463interactive <b>pcretest</b> run. 464<pre> 465 $ pcretest 466 PCRE version 7.0 30-Nov-2006 467 468 re> /^abc(\d+)/ 469 data> abc123 470 0: abc123 471 1: 123 472 data> xyz 473 No match 474</pre> 475Note that unset capturing substrings that are not followed by one that is set 476are not returned by <b>pcre_exec()</b>, and are not shown by <b>pcretest</b>. In 477the following example, there are two capturing substrings, but when the first 478data line is matched, the second, unset substring is not shown. An "internal" 479unset substring is shown as "<unset>", as for the second data line. 480<pre> 481 re> /(a)|(b)/ 482 data> a 483 0: a 484 1: a 485 data> b 486 0: b 487 1: <unset> 488 2: b 489</pre> 490If the strings contain any non-printing characters, they are output as \0x 491escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the 492pattern. See below for the definition of non-printing characters. If the 493pattern has the <b>/+</b> modifier, the output for substring 0 is followed by 494the the rest of the subject string, identified by "0+" like this: 495<pre> 496 re> /cat/+ 497 data> cataract 498 0: cat 499 0+ aract 500</pre> 501If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive 502matching attempts are output in sequence, like this: 503<pre> 504 re> /\Bi(\w\w)/g 505 data> Mississippi 506 0: iss 507 1: ss 508 0: iss 509 1: ss 510 0: ipp 511 1: pp 512</pre> 513"No match" is output only if the first match attempt fails. 514</P> 515<P> 516If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a 517data line that is successfully matched, the substrings extracted by the 518convenience functions are output with C, G, or L after the string number 519instead of a colon. This is in addition to the normal full list. The string 520length (that is, the return from the extraction function) is given in 521parentheses after each string for <b>\C</b> and <b>\G</b>. 522</P> 523<P> 524Note that whereas patterns can be continued over several lines (a plain ">" 525prompt is used for continuations), data lines may not. However newlines can be 526included in data by means of the \n escape (or \r, \r\n, etc., depending on 527the newline sequence setting). 528</P> 529<br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br> 530<P> 531When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by 532means of the \D escape sequence or the <b>-dfa</b> command line option), the 533output consists of a list of all the matches that start at the first point in 534the subject where there is at least one match. For example: 535<pre> 536 re> /(tang|tangerine|tan)/ 537 data> 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 543longest matching string is always given first (and numbered zero). After a 544PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the 545partially matching substring. 546</P> 547<P> 548If <b>/g</b> is present on the pattern, the search for further matches resumes 549at the end of the longest match. For example: 550<pre> 551 re> /(tang|tangerine|tan)/g 552 data> 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> 560Since the matching function does not support substring capture, the escape 561sequences 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> 565When the alternative matching function has given the PCRE_ERROR_PARTIAL return, 566indicating that the subject partially matched the pattern, you can restart the 567match with additional subject data by means of the \R escape sequence. For 568example: 569<pre> 570 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ 571 data> 23ja\P\D 572 Partial match: 23ja 573 data> n05\R\D 574 0: n05 575</pre> 576For further information about partial matching, see the 577<a href="pcrepartial.html"><b>pcrepartial</b></a> 578documentation. 579</P> 580<br><a name="SEC10" href="#TOC1">CALLOUTS</a><br> 581<P> 582If the pattern contains any callout requests, <b>pcretest</b>'s callout function 583is called during matching. This works with both matching functions. By default, 584the called function displays the callout number, the start and current 585positions in the text at the callout time, and the next pattern item to be 586tested. For example, the output 587<pre> 588 --->pqrabcdef 589 0 ^ ^ \d 590</pre> 591indicates that callout number 0 occurred for a match attempt starting at the 592fourth character of the subject string, when the pointer was at the seventh 593character of the data, and when the next pattern item was \d. Just one 594circumflex is output if the start and current positions are the same. 595</P> 596<P> 597Callouts numbered 255 are assumed to be automatic callouts, inserted as a 598result of the <b>/C</b> pattern modifier. In this case, instead of showing the 599callout number, the offset in the pattern, preceded by a plus, is output. For 600example: 601<pre> 602 re> /\d?[A-E]\*/C 603 data> E* 604 --->E* 605 +0 ^ \d? 606 +3 ^ [A-E] 607 +8 ^^ \* 608 +10 ^ ^ 609 0: E* 610</pre> 611The callout function in <b>pcretest</b> returns zero (carry on matching) by 612default, but you can use a \C item in a data line (as described above) to 613change this. 614</P> 615<P> 616Inserting callouts can be helpful when using <b>pcretest</b> to check 617complicated regular expressions. For further information about callouts, see 618the 619<a href="pcrecallout.html"><b>pcrecallout</b></a> 620documentation. 621</P> 622<br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br> 623<P> 624When <b>pcretest</b> is outputting text in the compiled version of a pattern, 625bytes other than 32-126 are always treated as non-printing characters are are 626therefore shown as hex escapes. 627</P> 628<P> 629When <b>pcretest</b> is outputting text that is a matched part of a subject 630string, it behaves in the same way, unless a different locale has been set for 631the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b> 632function 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> 636The facilities described in this section are not available when the POSIX 637inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is 638specified. 639</P> 640<P> 641When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a 642compiled pattern to a file, by following the modifiers with > and a file name. 643For example: 644<pre> 645 /pattern/im >/some/file 646</pre> 647See the 648<a href="pcreprecompile.html"><b>pcreprecompile</b></a> 649documentation for a discussion about saving and re-using compiled patterns. 650</P> 651<P> 652The data that is written is binary. The first eight bytes are the length of the 653compiled pattern data followed by the length of the optional study data, each 654written as four bytes in big-endian order (most significant byte first). If 655there is no study data (either the pattern was not studied, or studying did not 656return any data), the second length is zero. The lengths are followed by an 657exact copy of the compiled pattern. If there is additional study data, this 658follows immediately after the compiled pattern. After writing the file, 659<b>pcretest</b> expects to read a new pattern. 660</P> 661<P> 662A saved pattern can be reloaded into <b>pcretest</b> by specifing < and a file 663name instead of a pattern. The name of the file must not contain a < character, 664as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by < 665characters. 666For example: 667<pre> 668 re> </some/file 669 Compiled regex loaded from /some/file 670 No study data 671</pre> 672When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in 673the usual way. 674</P> 675<P> 676You can copy a file written by <b>pcretest</b> to a different host and reload it 677there, even if the new host has opposite endianness to the one on which the 678pattern was compiled. For example, you can compile on an i86 machine and run on 679a SPARC machine. 680</P> 681<P> 682File names for saving and reloading can be absolute or relative, but note that 683the shell facility of expanding a file name that starts with a tilde (~) is not 684available. 685</P> 686<P> 687The ability to save and reload files in <b>pcretest</b> is intended for testing 688and experimentation. It is not intended for production use because only a 689single pattern can be written to a file. Furthermore, there is no facility for 690supplying custom character tables for use with a reloaded pattern. If the 691original pattern was compiled with custom tables, an attempt to match a subject 692string using a reloaded pattern is likely to cause <b>pcretest</b> to crash. 693Finally, if you attempt to load a file that is not in the correct format, the 694result is undefined. 695</P> 696<br><a name="SEC13" href="#TOC1">SEE ALSO</a><br> 697<P> 698<b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3), 699<b>pcrepartial</b>(d), <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3). 700</P> 701<br><a name="SEC14" href="#TOC1">AUTHOR</a><br> 702<P> 703Philip Hazel 704<br> 705University Computing Service 706<br> 707Cambridge CB2 3QH, England. 708<br> 709</P> 710<br><a name="SEC15" href="#TOC1">REVISION</a><br> 711<P> 712Last updated: 26 September 2009 713<br> 714Copyright © 1997-2009 University of Cambridge. 715<br> 716<p> 717Return to the <a href="index.html">PCRE index page</a>. 718</p> 719