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> 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 <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 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 documentation. For details of the PCRE library function calls and their 43 options, see the 44 <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 <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 <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 Behave as if each regex has the <b>/D</b> (debug) modifier; the internal 61 form 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> 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 <b>-help</b> 72 Output a brief summary these options and then exit. 73 </P> 74 <P> 75 <b>-i</b> 76 Behave as if each regex has the <b>/I</b> modifier; information about the 77 compiled pattern is given after compilation. 78 </P> 79 <P> 80 <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 <b>-m</b> 87 Output the size of each compiled pattern after it has been compiled. This is 88 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 </P> 91 <P> 92 <b>-o</b> <i>osize</i> 93 Set 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 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 </P> 100 <P> 101 <b>-p</b> 102 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 </P> 106 <P> 107 <b>-q</b> 108 Do 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> 112 On Unix-like systems, set the size of the runtime stack to <i>size</i> 113 megabytes. 114 </P> 115 <P> 116 <b>-t</b> 117 Run each compile, study, and match many times with a timer, and output 118 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 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 </P> 125 <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 <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>" to prompt for regular 136 expressions, and "data>" to prompt for data lines. 137 </P> 138 <P> 139 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 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 Each data line is matched separately and independently. If you want to do 152 multi-line matches, you have to use the \n escape sequence (or \r or \r\n, 153 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 buffer is automatically extended if it is too small. 156 </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 non-alphanumeric delimiters other than backslash, for example: 161 <pre> 162 /(a|bc)x+yz/ 163 </pre> 164 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 </pre> 171 If you do so, the escape and the delimiter form part of the pattern, but since 172 delimiters are always non-alphanumeric, this does not affect its interpretation. 173 If the terminating delimiter is immediately followed by a backslash, for 174 example, 175 <pre> 176 /abc/\ 177 </pre> 178 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 </pre> 184 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 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 </P> 196 <P> 197 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 <pre> 202 /caseless/i 203 </pre> 204 The following table shows additional modifiers for setting PCRE compile-time 205 options that do not correspond to anything in Perl: 206 <pre> 207 <b>/8</b> PCRE_UTF8 208 <b>/?</b> PCRE_NO_UTF8_CHECK 209 <b>/A</b> PCRE_ANCHORED 210 <b>/C</b> PCRE_AUTO_CALLOUT 211 <b>/E</b> PCRE_DOLLAR_ENDONLY 212 <b>/f</b> PCRE_FIRSTLINE 213 <b>/J</b> PCRE_DUPNAMES 214 <b>/N</b> PCRE_NO_AUTO_CAPTURE 215 <b>/U</b> PCRE_UNGREEDY 216 <b>/W</b> PCRE_UCP 217 <b>/X</b> PCRE_EXTRA 218 <b>/Y</b> PCRE_NO_START_OPTIMIZE 219 <b>/<JS></b> PCRE_JAVASCRIPT_COMPAT 220 <b>/<cr></b> PCRE_NEWLINE_CR 221 <b>/<lf></b> PCRE_NEWLINE_LF 222 <b>/<crlf></b> PCRE_NEWLINE_CRLF 223 <b>/<anycrlf></b> PCRE_NEWLINE_ANYCRLF 224 <b>/<any></b> PCRE_NEWLINE_ANY 225 <b>/<bsr_anycrlf></b> PCRE_BSR_ANYCRLF 226 <b>/<bsr_unicode></b> PCRE_BSR_UNICODE 227 </pre> 228 The modifiers that are enclosed in angle brackets are literal strings as shown, 229 including the angle brackets, but the letters can be in either case. This 230 example sets multiline matching with CRLF as the line ending sequence: 231 <pre> 232 /^abc/m<crlf> 233 </pre> 234 As well as turning on the PCRE_UTF8 option, the <b>/8</b> modifier also causes 235 any non-printing characters in output strings to be printed using the 236 \x{hh...} notation if they are valid UTF-8 sequences. Full details of the PCRE 237 options are given in the 238 <a href="pcreapi.html"><b>pcreapi</b></a> 239 documentation. 240 </P> 241 <br><b> 242 Finding all matches in a string 243 </b><br> 244 <P> 245 Searching for all possible matches within each subject string can be requested 246 by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called 247 again to search the remainder of the subject string. The difference between 248 <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to 249 <b>pcre_exec()</b> to start searching at a new point within the entire string 250 (which is in effect what Perl does), whereas the latter passes over a shortened 251 substring. This makes a difference to the matching process if the pattern 252 begins with a lookbehind assertion (including \b or \B). 253 </P> 254 <P> 255 If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an 256 empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and 257 PCRE_ANCHORED flags set in order to search for another, non-empty, match at the 258 same point. If this second match fails, the start offset is advanced, and the 259 normal match is retried. This imitates the way Perl handles such cases when 260 using the <b>/g</b> modifier or the <b>split()</b> function. Normally, the start 261 offset is advanced by one character, but if the newline convention recognizes 262 CRLF as a newline, and the current character is CR followed by LF, an advance 263 of two is used. 264 </P> 265 <br><b> 266 Other modifiers 267 </b><br> 268 <P> 269 There are yet more modifiers for controlling the way <b>pcretest</b> 270 operates. 271 </P> 272 <P> 273 The <b>/+</b> modifier requests that as well as outputting the substring that 274 matched the entire pattern, pcretest should in addition output the remainder of 275 the subject string. This is useful for tests where the subject contains 276 multiple copies of the same substring. 277 </P> 278 <P> 279 The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b> 280 output a representation of the compiled byte code after compilation. Normally 281 this information contains length and offset values; however, if <b>/Z</b> is 282 also present, this data is replaced by spaces. This is a special feature for 283 use in the automatic test scripts; it ensures that the same output is generated 284 for different internal link sizes. 285 </P> 286 <P> 287 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to 288 <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers. 289 </P> 290 <P> 291 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the 292 fields in the compiled pattern that contain 2-byte and 4-byte numbers. This 293 facility is for testing the feature in PCRE that allows it to execute patterns 294 that were compiled on a host with a different endianness. This feature is not 295 available when the POSIX interface to PCRE is being used, that is, when the 296 <b>/P</b> pattern modifier is specified. See also the section about saving and 297 reloading compiled patterns below. 298 </P> 299 <P> 300 The <b>/I</b> modifier requests that <b>pcretest</b> output information about the 301 compiled pattern (whether it is anchored, has a fixed first character, and 302 so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a 303 pattern. If the pattern is studied, the results of that are also output. 304 </P> 305 <P> 306 The <b>/K</b> modifier requests <b>pcretest</b> to show names from backtracking 307 control verbs that are returned from calls to <b>pcre_exec()</b>. It causes 308 <b>pcretest</b> to create a <b>pcre_extra</b> block if one has not already been 309 created by a call to <b>pcre_study()</b>, and to set the PCRE_EXTRA_MARK flag 310 and the <b>mark</b> field within it, every time that <b>pcre_exec()</b> is 311 called. If the variable that the <b>mark</b> field points to is non-NULL for a 312 match, non-match, or partial match, <b>pcretest</b> prints the string to which 313 it points. For a match, this is shown on a line by itself, tagged with "MK:". 314 For a non-match it is added to the message. 315 </P> 316 <P> 317 The <b>/L</b> modifier must be followed directly by the name of a locale, for 318 example, 319 <pre> 320 /pattern/Lfr_FR 321 </pre> 322 For this reason, it must be the last modifier. The given locale is set, 323 <b>pcre_maketables()</b> is called to build a set of character tables for the 324 locale, and this is then passed to <b>pcre_compile()</b> when compiling the 325 regular expression. Without an <b>/L</b> (or <b>/T</b>) modifier, NULL is passed 326 as the tables pointer; that is, <b>/L</b> applies only to the expression on 327 which it appears. 328 </P> 329 <P> 330 The <b>/M</b> modifier causes the size of memory block used to hold the compiled 331 pattern to be output. 332 </P> 333 <P> 334 The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the 335 expression has been compiled, and the results used when the expression is 336 matched. 337 </P> 338 <P> 339 The <b>/T</b> modifier must be followed by a single digit. It causes a specific 340 set of built-in character tables to be passed to <b>pcre_compile()</b>. It is 341 used in the standard PCRE tests to check behaviour with different character 342 tables. The digit specifies the tables as follows: 343 <pre> 344 0 the default ASCII tables, as distributed in 345 pcre_chartables.c.dist 346 1 a set of tables defining ISO 8859 characters 347 </pre> 348 In table 1, some characters whose codes are greater than 128 are identified as 349 letters, digits, spaces, etc. 350 </P> 351 <br><b> 352 Using the POSIX wrapper API 353 </b><br> 354 <P> 355 The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper 356 API rather than its native API. When <b>/P</b> is set, the following modifiers 357 set options for the <b>regcomp()</b> function: 358 <pre> 359 /i REG_ICASE 360 /m REG_NEWLINE 361 /N REG_NOSUB 362 /s REG_DOTALL ) 363 /U REG_UNGREEDY ) These options are not part of 364 /W REG_UCP ) the POSIX standard 365 /8 REG_UTF8 ) 366 </pre> 367 The <b>/+</b> modifier works as described above. All other modifiers are 368 ignored. 369 </P> 370 <br><a name="SEC5" href="#TOC1">DATA LINES</a><br> 371 <P> 372 Before each data line is passed to <b>pcre_exec()</b>, leading and trailing 373 whitespace is removed, and it is then scanned for \ escapes. Some of these are 374 pretty esoteric features, intended for checking out some of the more 375 complicated features of PCRE. If you are just testing "ordinary" regular 376 expressions, you probably don't need any of these. The following escapes are 377 recognized: 378 <pre> 379 \a alarm (BEL, \x07) 380 \b backspace (\x08) 381 \e escape (\x27) 382 \f formfeed (\x0c) 383 \n newline (\x0a) 384 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits) 385 \r carriage return (\x0d) 386 \t tab (\x09) 387 \v vertical tab (\x0b) 388 \nnn octal character (up to 3 octal digits) 389 always a byte unless > 255 in UTF-8 mode 390 \xhh hexadecimal byte (up to 2 hex digits) 391 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode 392 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 393 \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 394 \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32) 395 \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin- 396 ated by next non alphanumeric character) 397 \C+ show the current captured substrings at callout time 398 \C- do not supply a callout function 399 \C!n return 1 instead of 0 when callout number n is reached 400 \C!n!m return 1 instead of 0 when callout number n is reached for the nth time 401 \C*n pass the number n (may be negative) as callout data; this is used as the callout return value 402 \D use the <b>pcre_dfa_exec()</b> match function 403 \F only shortest match for <b>pcre_dfa_exec()</b> 404 \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32) 405 \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin- 406 ated by next non-alphanumeric character) 407 \L call pcre_get_substringlist() after a successful match 408 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings 409 \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the 410 PCRE_NOTEMPTY_ATSTART option 411 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits) 412 \P pass the PCRE_PARTIAL_SOFT option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the 413 PCRE_PARTIAL_HARD option 414 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits) 415 \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b> 416 \S output details of memory get/free calls during matching 417 \Y pass the PCRE_NO_START_OPTIMIZE option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 418 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 419 \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 420 \>dd start the match at offset dd (optional "-"; then any number of digits); this sets the <i>startoffset</i> 421 argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 422 \<cr> pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 423 \<lf> pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 424 \<crlf> pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 425 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 426 \<any> pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 427 </pre> 428 Note that \xhh always specifies one byte, even in UTF-8 mode; this makes it 429 possible to construct invalid UTF-8 sequences for testing purposes. On the 430 other hand, \x{hh} is interpreted as a UTF-8 character in UTF-8 mode, 431 generating more than one byte if the value is greater than 127. When not in 432 UTF-8 mode, it generates one byte for values less than 256, and causes an error 433 for greater values. 434 </P> 435 <P> 436 The escapes that specify line ending sequences are literal strings, exactly as 437 shown. No more than one newline setting should be present in any data line. 438 </P> 439 <P> 440 A backslash followed by anything else just escapes the anything else. If 441 the very last character is a backslash, it is ignored. This gives a way of 442 passing an empty line as data, since a real empty line terminates the data 443 input. 444 </P> 445 <P> 446 If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with 447 different values in the <i>match_limit</i> and <i>match_limit_recursion</i> 448 fields of the <b>pcre_extra</b> data structure, until it finds the minimum 449 numbers for each parameter that allow <b>pcre_exec()</b> to complete. The 450 <i>match_limit</i> number is a measure of the amount of backtracking that takes 451 place, and checking it out can be instructive. For most simple matches, the 452 number is quite small, but for patterns with very large numbers of matching 453 possibilities, it can become large very quickly with increasing length of 454 subject string. The <i>match_limit_recursion</i> number is a measure of how much 455 stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed 456 to complete the match attempt. 457 </P> 458 <P> 459 When \O is used, the value specified may be higher or lower than the size set 460 by the <b>-O</b> command line option (or defaulted to 45); \O applies only to 461 the call of <b>pcre_exec()</b> for the line in which it appears. 462 </P> 463 <P> 464 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper 465 API to be used, the only option-setting sequences that have any effect are \B, 466 \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively, 467 to be passed to <b>regexec()</b>. 468 </P> 469 <P> 470 The use of \x{hh...} to represent UTF-8 characters is not dependent on the use 471 of the <b>/8</b> modifier on the pattern. It is recognized always. There may be 472 any number of hexadecimal digits inside the braces. The result is from one to 473 six bytes, encoded according to the original UTF-8 rules of RFC 2279. This 474 allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are 475 valid Unicode code points, or indeed valid UTF-8 characters according to the 476 later rules in RFC 3629. 477 </P> 478 <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br> 479 <P> 480 By default, <b>pcretest</b> uses the standard PCRE matching function, 481 <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an 482 alternative matching function, <b>pcre_dfa_test()</b>, which operates in a 483 different way, and has some restrictions. The differences between the two 484 functions are described in the 485 <a href="pcrematching.html"><b>pcrematching</b></a> 486 documentation. 487 </P> 488 <P> 489 If a data line contains the \D escape sequence, or if the command line 490 contains the <b>-dfa</b> option, the alternative matching function is called. 491 This function finds all possible matches at a given point. If, however, the \F 492 escape sequence is present in the data line, it stops after the first match is 493 found. This is always the shortest possible match. 494 </P> 495 <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br> 496 <P> 497 This section describes the output when the normal matching function, 498 <b>pcre_exec()</b>, is being used. 499 </P> 500 <P> 501 When a match succeeds, pcretest outputs the list of captured substrings that 502 <b>pcre_exec()</b> returns, starting with number 0 for the string that matched 503 the whole pattern. Otherwise, it outputs "No match" when the return is 504 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching 505 substring when <b>pcre_exec()</b> returns PCRE_ERROR_PARTIAL. (Note that this is 506 the entire substring that was inspected during the partial match; it may 507 include characters before the actual match start if a lookbehind assertion, 508 \K, \b, or \B was involved.) For any other returns, it outputs the PCRE 509 negative error number. Here is an example of an interactive <b>pcretest</b> run. 510 <pre> 511 $ pcretest 512 PCRE version 7.0 30-Nov-2006 513 514 re> /^abc(\d+)/ 515 data> abc123 516 0: abc123 517 1: 123 518 data> xyz 519 No match 520 </pre> 521 Note that unset capturing substrings that are not followed by one that is set 522 are not returned by <b>pcre_exec()</b>, and are not shown by <b>pcretest</b>. In 523 the following example, there are two capturing substrings, but when the first 524 data line is matched, the second, unset substring is not shown. An "internal" 525 unset substring is shown as "<unset>", as for the second data line. 526 <pre> 527 re> /(a)|(b)/ 528 data> a 529 0: a 530 1: a 531 data> b 532 0: b 533 1: <unset> 534 2: b 535 </pre> 536 If the strings contain any non-printing characters, they are output as \0x 537 escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the 538 pattern. See below for the definition of non-printing characters. If the 539 pattern has the <b>/+</b> modifier, the output for substring 0 is followed by 540 the the rest of the subject string, identified by "0+" like this: 541 <pre> 542 re> /cat/+ 543 data> cataract 544 0: cat 545 0+ aract 546 </pre> 547 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive 548 matching attempts are output in sequence, like this: 549 <pre> 550 re> /\Bi(\w\w)/g 551 data> Mississippi 552 0: iss 553 1: ss 554 0: iss 555 1: ss 556 0: ipp 557 1: pp 558 </pre> 559 "No match" is output only if the first match attempt fails. 560 </P> 561 <P> 562 If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a 563 data line that is successfully matched, the substrings extracted by the 564 convenience functions are output with C, G, or L after the string number 565 instead of a colon. This is in addition to the normal full list. The string 566 length (that is, the return from the extraction function) is given in 567 parentheses after each string for <b>\C</b> and <b>\G</b>. 568 </P> 569 <P> 570 Note that whereas patterns can be continued over several lines (a plain ">" 571 prompt is used for continuations), data lines may not. However newlines can be 572 included in data by means of the \n escape (or \r, \r\n, etc., depending on 573 the newline sequence setting). 574 </P> 575 <br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br> 576 <P> 577 When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by 578 means of the \D escape sequence or the <b>-dfa</b> command line option), the 579 output consists of a list of all the matches that start at the first point in 580 the subject where there is at least one match. For example: 581 <pre> 582 re> /(tang|tangerine|tan)/ 583 data> yellow tangerine\D 584 0: tangerine 585 1: tang 586 2: tan 587 </pre> 588 (Using the normal matching function on this data finds only "tang".) The 589 longest matching string is always given first (and numbered zero). After a 590 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the 591 partially matching substring. (Note that this is the entire substring that was 592 inspected during the partial match; it may include characters before the actual 593 match start if a lookbehind assertion, \K, \b, or \B was involved.) 594 </P> 595 <P> 596 If <b>/g</b> is present on the pattern, the search for further matches resumes 597 at the end of the longest match. For example: 598 <pre> 599 re> /(tang|tangerine|tan)/g 600 data> yellow tangerine and tangy sultana\D 601 0: tangerine 602 1: tang 603 2: tan 604 0: tang 605 1: tan 606 0: tan 607 </pre> 608 Since the matching function does not support substring capture, the escape 609 sequences that are concerned with captured substrings are not relevant. 610 </P> 611 <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br> 612 <P> 613 When the alternative matching function has given the PCRE_ERROR_PARTIAL return, 614 indicating that the subject partially matched the pattern, you can restart the 615 match with additional subject data by means of the \R escape sequence. For 616 example: 617 <pre> 618 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ 619 data> 23ja\P\D 620 Partial match: 23ja 621 data> n05\R\D 622 0: n05 623 </pre> 624 For further information about partial matching, see the 625 <a href="pcrepartial.html"><b>pcrepartial</b></a> 626 documentation. 627 </P> 628 <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br> 629 <P> 630 If the pattern contains any callout requests, <b>pcretest</b>'s callout function 631 is called during matching. This works with both matching functions. By default, 632 the called function displays the callout number, the start and current 633 positions in the text at the callout time, and the next pattern item to be 634 tested. For example, the output 635 <pre> 636 --->pqrabcdef 637 0 ^ ^ \d 638 </pre> 639 indicates that callout number 0 occurred for a match attempt starting at the 640 fourth character of the subject string, when the pointer was at the seventh 641 character of the data, and when the next pattern item was \d. Just one 642 circumflex is output if the start and current positions are the same. 643 </P> 644 <P> 645 Callouts numbered 255 are assumed to be automatic callouts, inserted as a 646 result of the <b>/C</b> pattern modifier. In this case, instead of showing the 647 callout number, the offset in the pattern, preceded by a plus, is output. For 648 example: 649 <pre> 650 re> /\d?[A-E]\*/C 651 data> E* 652 --->E* 653 +0 ^ \d? 654 +3 ^ [A-E] 655 +8 ^^ \* 656 +10 ^ ^ 657 0: E* 658 </pre> 659 The callout function in <b>pcretest</b> returns zero (carry on matching) by 660 default, but you can use a \C item in a data line (as described above) to 661 change this. 662 </P> 663 <P> 664 Inserting callouts can be helpful when using <b>pcretest</b> to check 665 complicated regular expressions. For further information about callouts, see 666 the 667 <a href="pcrecallout.html"><b>pcrecallout</b></a> 668 documentation. 669 </P> 670 <br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br> 671 <P> 672 When <b>pcretest</b> is outputting text in the compiled version of a pattern, 673 bytes other than 32-126 are always treated as non-printing characters are are 674 therefore shown as hex escapes. 675 </P> 676 <P> 677 When <b>pcretest</b> is outputting text that is a matched part of a subject 678 string, it behaves in the same way, unless a different locale has been set for 679 the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b> 680 function to distinguish printing and non-printing characters. 681 </P> 682 <br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br> 683 <P> 684 The facilities described in this section are not available when the POSIX 685 inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is 686 specified. 687 </P> 688 <P> 689 When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a 690 compiled pattern to a file, by following the modifiers with > and a file name. 691 For example: 692 <pre> 693 /pattern/im >/some/file 694 </pre> 695 See the 696 <a href="pcreprecompile.html"><b>pcreprecompile</b></a> 697 documentation for a discussion about saving and re-using compiled patterns. 698 </P> 699 <P> 700 The data that is written is binary. The first eight bytes are the length of the 701 compiled pattern data followed by the length of the optional study data, each 702 written as four bytes in big-endian order (most significant byte first). If 703 there is no study data (either the pattern was not studied, or studying did not 704 return any data), the second length is zero. The lengths are followed by an 705 exact copy of the compiled pattern. If there is additional study data, this 706 follows immediately after the compiled pattern. After writing the file, 707 <b>pcretest</b> expects to read a new pattern. 708 </P> 709 <P> 710 A saved pattern can be reloaded into <b>pcretest</b> by specifing < and a file 711 name instead of a pattern. The name of the file must not contain a < character, 712 as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by < 713 characters. 714 For example: 715 <pre> 716 re> </some/file 717 Compiled regex loaded from /some/file 718 No study data 719 </pre> 720 When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in 721 the usual way. 722 </P> 723 <P> 724 You can copy a file written by <b>pcretest</b> to a different host and reload it 725 there, even if the new host has opposite endianness to the one on which the 726 pattern was compiled. For example, you can compile on an i86 machine and run on 727 a SPARC machine. 728 </P> 729 <P> 730 File names for saving and reloading can be absolute or relative, but note that 731 the shell facility of expanding a file name that starts with a tilde (~) is not 732 available. 733 </P> 734 <P> 735 The ability to save and reload files in <b>pcretest</b> is intended for testing 736 and experimentation. It is not intended for production use because only a 737 single pattern can be written to a file. Furthermore, there is no facility for 738 supplying custom character tables for use with a reloaded pattern. If the 739 original pattern was compiled with custom tables, an attempt to match a subject 740 string using a reloaded pattern is likely to cause <b>pcretest</b> to crash. 741 Finally, if you attempt to load a file that is not in the correct format, the 742 result is undefined. 743 </P> 744 <br><a name="SEC13" href="#TOC1">SEE ALSO</a><br> 745 <P> 746 <b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3), 747 <b>pcrepartial</b>(d), <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3). 748 </P> 749 <br><a name="SEC14" href="#TOC1">AUTHOR</a><br> 750 <P> 751 Philip Hazel 752 <br> 753 University Computing Service 754 <br> 755 Cambridge CB2 3QH, England. 756 <br> 757 </P> 758 <br><a name="SEC15" href="#TOC1">REVISION</a><br> 759 <P> 760 Last updated: 21 November 2010 761 <br> 762 Copyright © 1997-2010 University of Cambridge. 763 <br> 764 <p> 765 Return to the <a href="index.html">PCRE index page</a>. 766 </p> 767
