# Contents of /code/trunk/doc/pcretest.1

 1 .TH PCRETEST 1 "09 February 2014" "PCRE 8.35" 2 .SH NAME 3 pcretest - a program for testing Perl-compatible regular expressions. 4 .SH SYNOPSIS 5 .rs 6 .sp 7 .B pcretest "[options] [input file [output file]]" 8 .sp 9 \fBpcretest\fP was written as a test program for the PCRE regular expression 10 library itself, but it can also be used for experimenting with regular 11 expressions. This document describes the features of the test program; for 12 details of the regular expressions themselves, see the 13 .\" HREF 14 \fBpcrepattern\fP 15 .\" 16 documentation. For details of the PCRE library function calls and their 17 options, see the 18 .\" HREF 19 \fBpcreapi\fP 20 .\" 21 , 22 .\" HREF 23 \fBpcre16\fP 24 and 25 .\" HREF 26 \fBpcre32\fP 27 .\" 28 documentation. 29 .P 30 The input for \fBpcretest\fP is a sequence of regular expression patterns and 31 strings to be matched, as described below. The output shows the result of each 32 match. Options on the command line and the patterns control PCRE options and 33 exactly what is output. 34 .P 35 As PCRE has evolved, it has acquired many different features, and as a result, 36 \fBpcretest\fP now has rather a lot of obscure options for testing every 37 possible feature. Some of these options are specifically designed for use in 38 conjunction with the test script and data files that are distributed as part of 39 PCRE, and are unlikely to be of use otherwise. They are all documented here, 40 but without much justification. 41 . 42 . 43 .SH "INPUT DATA FORMAT" 44 .rs 45 .sp 46 Input to \fBpcretest\fP is processed line by line, either by calling the C 47 library's \fBfgets()\fP function, or via the \fBlibreadline\fP library (see 48 below). In Unix-like environments, \fBfgets()\fP treats any bytes other than 49 newline as data characters. However, in some Windows environments character 26 50 (hex 1A) causes an immediate end of file, and no further data is read. For 51 maximum portability, therefore, it is safest to use only ASCII characters in 52 \fBpcretest\fP input files. 53 . 54 . 55 .SH "PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES" 56 .rs 57 .sp 58 From release 8.30, two separate PCRE libraries can be built. The original one 59 supports 8-bit character strings, whereas the newer 16-bit library supports 60 character strings encoded in 16-bit units. From release 8.32, a third library 61 can be built, supporting character strings encoded in 32-bit units. The 62 \fBpcretest\fP program can be used to test all three libraries. However, it is 63 itself still an 8-bit program, reading 8-bit input and writing 8-bit output. 64 When testing the 16-bit or 32-bit library, the patterns and data strings are 65 converted to 16- or 32-bit format before being passed to the PCRE library 66 functions. Results are converted to 8-bit for output. 67 .P 68 References to functions and structures of the form \fBpcre[16|32]_xx\fP below 69 mean "\fBpcre_xx\fP when using the 8-bit library, \fBpcre16_xx\fP when using 70 the 16-bit library, or \fBpcre32_xx\fP when using the 32-bit library". 71 . 72 . 73 .SH "COMMAND LINE OPTIONS" 74 .rs 75 .TP 10 76 \fB-8\fP 77 If both the 8-bit library has been built, this option causes the 8-bit library 78 to be used (which is the default); if the 8-bit library has not been built, 79 this option causes an error. 80 .TP 10 81 \fB-16\fP 82 If both the 8-bit or the 32-bit, and the 16-bit libraries have been built, this 83 option causes the 16-bit library to be used. If only the 16-bit library has been 84 built, this is the default (so has no effect). If only the 8-bit or the 32-bit 85 library has been built, this option causes an error. 86 .TP 10 87 \fB-32\fP 88 If both the 8-bit or the 16-bit, and the 32-bit libraries have been built, this 89 option causes the 32-bit library to be used. If only the 32-bit library has been 90 built, this is the default (so has no effect). If only the 8-bit or the 16-bit 91 library has been built, this option causes an error. 92 .TP 10 93 \fB-b\fP 94 Behave as if each pattern has the \fB/B\fP (show byte code) modifier; the 95 internal form is output after compilation. 96 .TP 10 97 \fB-C\fP 98 Output the version number of the PCRE library, and all available information 99 about the optional features that are included, and then exit with zero exit 100 code. All other options are ignored. 101 .TP 10 102 \fB-C\fP \fIoption\fP 103 Output information about a specific build-time option, then exit. This 104 functionality is intended for use in scripts such as \fBRunTest\fP. The 105 following options output the value and set the exit code as indicated: 106 .sp 107 ebcdic-nl the code for LF (= NL) in an EBCDIC environment: 108 0x15 or 0x25 109 0 if used in an ASCII environment 110 exit code is always 0 111 linksize the configured internal link size (2, 3, or 4) 112 exit code is set to the link size 113 newline the default newline setting: 114 CR, LF, CRLF, ANYCRLF, or ANY 115 exit code is always 0 116 bsr the default setting for what \eR matches: 117 ANYCRLF or ANY 118 exit code is always 0 119 .sp 120 The following options output 1 for true or 0 for false, and set the exit code 121 to the same value: 122 .sp 123 ebcdic compiled for an EBCDIC environment 124 jit just-in-time support is available 125 pcre16 the 16-bit library was built 126 pcre32 the 32-bit library was built 127 pcre8 the 8-bit library was built 128 ucp Unicode property support is available 129 utf UTF-8 and/or UTF-16 and/or UTF-32 support 130 is available 131 .sp 132 If an unknown option is given, an error message is output; the exit code is 0. 133 .TP 10 134 \fB-d\fP 135 Behave as if each pattern has the \fB/D\fP (debug) modifier; the internal 136 form and information about the compiled pattern is output after compilation; 137 \fB-d\fP is equivalent to \fB-b -i\fP. 138 .TP 10 139 \fB-dfa\fP 140 Behave as if each data line contains the \eD escape sequence; this causes the 141 alternative matching function, \fBpcre[16|32]_dfa_exec()\fP, to be used instead 142 of the standard \fBpcre[16|32]_exec()\fP function (more detail is given below). 143 .TP 10 144 \fB-help\fP 145 Output a brief summary these options and then exit. 146 .TP 10 147 \fB-i\fP 148 Behave as if each pattern has the \fB/I\fP modifier; information about the 149 compiled pattern is given after compilation. 150 .TP 10 151 \fB-M\fP 152 Behave as if each data line contains the \eM escape sequence; this causes 153 PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by 154 calling \fBpcre[16|32]_exec()\fP repeatedly with different limits. 155 .TP 10 156 \fB-m\fP 157 Output the size of each compiled pattern after it has been compiled. This is 158 equivalent to adding \fB/M\fP to each regular expression. The size is given in 159 bytes for both libraries. 160 .TP 10 161 \fB-O\fP 162 Behave as if each pattern has the \fB/O\fP modifier, that is disable 163 auto-possessification for all patterns. 164 .TP 10 165 \fB-o\fP \fIosize\fP 166 Set the number of elements in the output vector that is used when calling 167 \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP to be \fIosize\fP. The 168 default value is 45, which is enough for 14 capturing subexpressions for 169 \fBpcre[16|32]_exec()\fP or 22 different matches for 170 \fBpcre[16|32]_dfa_exec()\fP. 171 The vector size can be changed for individual matching calls by including \eO 172 in the data line (see below). 173 .TP 10 174 \fB-p\fP 175 Behave as if each pattern has the \fB/P\fP modifier; the POSIX wrapper API is 176 used to call PCRE. None of the other options has any effect when \fB-p\fP is 177 set. This option can be used only with the 8-bit library. 178 .TP 10 179 \fB-q\fP 180 Do not output the version number of \fBpcretest\fP at the start of execution. 181 .TP 10 182 \fB-S\fP \fIsize\fP 183 On Unix-like systems, set the size of the run-time stack to \fIsize\fP 184 megabytes. 185 .TP 10 186 \fB-s\fP or \fB-s+\fP 187 Behave as if each pattern has the \fB/S\fP modifier; in other words, force each 188 pattern to be studied. If \fB-s+\fP is used, all the JIT compile options are 189 passed to \fBpcre[16|32]_study()\fP, causing just-in-time optimization to be set 190 up if it is available, for both full and partial matching. Specific JIT compile 191 options can be selected by following \fB-s+\fP with a digit in the range 1 to 192 7, which selects the JIT compile modes as follows: 193 .sp 194 1 normal match only 195 2 soft partial match only 196 3 normal match and soft partial match 197 4 hard partial match only 198 6 soft and hard partial match 199 7 all three modes (default) 200 .sp 201 If \fB-s++\fP is used instead of \fB-s+\fP (with or without a following digit), 202 the text "(JIT)" is added to the first output line after a match or no match 203 when JIT-compiled code was actually used. 204 .sp 205 Note that there are pattern options that can override \fB-s\fP, either 206 specifying no studying at all, or suppressing JIT compilation. 207 .sp 208 If the \fB/I\fP or \fB/D\fP option is present on a pattern (requesting output 209 about the compiled pattern), information about the result of studying is not 210 included when studying is caused only by \fB-s\fP and neither \fB-i\fP nor 211 \fB-d\fP is present on the command line. This behaviour means that the output 212 from tests that are run with and without \fB-s\fP should be identical, except 213 when options that output information about the actual running of a match are 214 set. 215 .sp 216 The \fB-M\fP, \fB-t\fP, and \fB-tm\fP options, which give information about 217 resources used, are likely to produce different output with and without 218 \fB-s\fP. Output may also differ if the \fB/C\fP option is present on an 219 individual pattern. This uses callouts to trace the the matching process, and 220 this may be different between studied and non-studied patterns. If the pattern 221 contains (*MARK) items there may also be differences, for the same reason. The 222 \fB-s\fP command line option can be overridden for specific patterns that 223 should never be studied (see the \fB/S\fP pattern modifier below). 224 .TP 10 225 \fB-t\fP 226 Run each compile, study, and match many times with a timer, and output the 227 resulting times per compile, study, or match (in milliseconds). Do not set 228 \fB-m\fP with \fB-t\fP, because you will then get the size output a zillion 229 times, and the timing will be distorted. You can control the number of 230 iterations that are used for timing by following \fB-t\fP with a number (as a 231 separate item on the command line). For example, "-t 1000" iterates 1000 times. 232 The default is to iterate 500000 times. 233 .TP 10 234 \fB-tm\fP 235 This is like \fB-t\fP except that it times only the matching phase, not the 236 compile or study phases. 237 .TP 10 238 \fB-T\fP \fB-TM\fP 239 These behave like \fB-t\fP and \fB-tm\fP, but in addition, at the end of a run, 240 the total times for all compiles, studies, and matches are output. 241 . 242 . 243 .SH DESCRIPTION 244 .rs 245 .sp 246 If \fBpcretest\fP is given two filename arguments, it reads from the first and 247 writes to the second. If it is given only one filename argument, it reads from 248 that file and writes to stdout. Otherwise, it reads from stdin and writes to 249 stdout, and prompts for each line of input, using "re>" to prompt for regular 250 expressions, and "data>" to prompt for data lines. 251 .P 252 When \fBpcretest\fP is built, a configuration option can specify that it should 253 be linked with the \fBlibreadline\fP library. When this is done, if the input 254 is from a terminal, it is read using the \fBreadline()\fP function. This 255 provides line-editing and history facilities. The output from the \fB-help\fP 256 option states whether or not \fBreadline()\fP will be used. 257 .P 258 The program handles any number of sets of input on a single input file. Each 259 set starts with a regular expression, and continues with any number of data 260 lines to be matched against that pattern. 261 .P 262 Each data line is matched separately and independently. If you want to do 263 multi-line matches, you have to use the \en escape sequence (or \er or \er\en, 264 etc., depending on the newline setting) in a single line of input to encode the 265 newline sequences. There is no limit on the length of data lines; the input 266 buffer is automatically extended if it is too small. 267 .P 268 An empty line signals the end of the data lines, at which point a new regular 269 expression is read. The regular expressions are given enclosed in any 270 non-alphanumeric delimiters other than backslash, for example: 271 .sp 272 /(a|bc)x+yz/ 273 .sp 274 White space before the initial delimiter is ignored. A regular expression may 275 be continued over several input lines, in which case the newline characters are 276 included within it. It is possible to include the delimiter within the pattern 277 by escaping it, for example 278 .sp 279 /abc\e/def/ 280 .sp 281 If you do so, the escape and the delimiter form part of the pattern, but since 282 delimiters are always non-alphanumeric, this does not affect its interpretation. 283 If the terminating delimiter is immediately followed by a backslash, for 284 example, 285 .sp 286 /abc/\e 287 .sp 288 then a backslash is added to the end of the pattern. This is done to provide a 289 way of testing the error condition that arises if a pattern finishes with a 290 backslash, because 291 .sp 292 /abc\e/ 293 .sp 294 is interpreted as the first line of a pattern that starts with "abc/", causing 295 pcretest to read the next line as a continuation of the regular expression. 296 . 297 . 298 .SH "PATTERN MODIFIERS" 299 .rs 300 .sp 301 A pattern may be followed by any number of modifiers, which are mostly single 302 characters, though some of these can be qualified by further characters. 303 Following Perl usage, these are referred to below as, for example, "the 304 \fB/i\fP modifier", even though the delimiter of the pattern need not always be 305 a slash, and no slash is used when writing modifiers. White space may appear 306 between the final pattern delimiter and the first modifier, and between the 307 modifiers themselves. For reference, here is a complete list of modifiers. They 308 fall into several groups that are described in detail in the following 309 sections. 310 .sp 311 \fB/8\fP set UTF mode 312 \fB/9\fP set PCRE_NEVER_UTF (locks out UTF mode) 313 \fB/?\fP disable UTF validity check 314 \fB/+\fP show remainder of subject after match 315 \fB/=\fP show all captures (not just those that are set) 316 .sp 317 \fB/A\fP set PCRE_ANCHORED 318 \fB/B\fP show compiled code 319 \fB/C\fP set PCRE_AUTO_CALLOUT 320 \fB/D\fP same as \fB/B\fP plus \fB/I\fP 321 \fB/E\fP set PCRE_DOLLAR_ENDONLY 322 \fB/F\fP flip byte order in compiled pattern 323 \fB/f\fP set PCRE_FIRSTLINE 324 \fB/G\fP find all matches (shorten string) 325 \fB/g\fP find all matches (use startoffset) 326 \fB/I\fP show information about pattern 327 \fB/i\fP set PCRE_CASELESS 328 \fB/J\fP set PCRE_DUPNAMES 329 \fB/K\fP show backtracking control names 330 \fB/L\fP set locale 331 \fB/M\fP show compiled memory size 332 \fB/m\fP set PCRE_MULTILINE 333 \fB/N\fP set PCRE_NO_AUTO_CAPTURE 334 \fB/O\fP set PCRE_NO_AUTO_POSSESS 335 \fB/P\fP use the POSIX wrapper 336 \fB/Q\fP test external stack check function 337 \fB/S\fP study the pattern after compilation 338 \fB/s\fP set PCRE_DOTALL 339 \fB/T\fP select character tables 340 \fB/U\fP set PCRE_UNGREEDY 341 \fB/W\fP set PCRE_UCP 342 \fB/X\fP set PCRE_EXTRA 343 \fB/x\fP set PCRE_EXTENDED 344 \fB/Y\fP set PCRE_NO_START_OPTIMIZE 345 \fB/Z\fP don't show lengths in \fB/B\fP output 346 .sp 347 \fB/\fP set PCRE_NEWLINE_ANY 348 \fB/\fP set PCRE_NEWLINE_ANYCRLF 349 \fB/\fP set PCRE_NEWLINE_CR 350 \fB/\fP set PCRE_NEWLINE_CRLF 351 \fB/\fP set PCRE_NEWLINE_LF 352 \fB/\fP set PCRE_BSR_ANYCRLF 353 \fB/\fP set PCRE_BSR_UNICODE 354 \fB/\fP set PCRE_JAVASCRIPT_COMPAT 355 .sp 356 . 357 . 358 .SS "Perl-compatible modifiers" 359 .rs 360 .sp 361 The \fB/i\fP, \fB/m\fP, \fB/s\fP, and \fB/x\fP modifiers set the PCRE_CASELESS, 362 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when 363 \fBpcre[16|32]_compile()\fP is called. These four modifier letters have the same 364 effect as they do in Perl. For example: 365 .sp 366 /caseless/i 367 .sp 368 . 369 . 370 .SS "Modifiers for other PCRE options" 371 .rs 372 .sp 373 The following table shows additional modifiers for setting PCRE compile-time 374 options that do not correspond to anything in Perl: 375 .sp 376 \fB/8\fP PCRE_UTF8 ) when using the 8-bit 377 \fB/?\fP PCRE_NO_UTF8_CHECK ) library 378 .sp 379 \fB/8\fP PCRE_UTF16 ) when using the 16-bit 380 \fB/?\fP PCRE_NO_UTF16_CHECK ) library 381 .sp 382 \fB/8\fP PCRE_UTF32 ) when using the 32-bit 383 \fB/?\fP PCRE_NO_UTF32_CHECK ) library 384 .sp 385 \fB/9\fP PCRE_NEVER_UTF 386 \fB/A\fP PCRE_ANCHORED 387 \fB/C\fP PCRE_AUTO_CALLOUT 388 \fB/E\fP PCRE_DOLLAR_ENDONLY 389 \fB/f\fP PCRE_FIRSTLINE 390 \fB/J\fP PCRE_DUPNAMES 391 \fB/N\fP PCRE_NO_AUTO_CAPTURE 392 \fB/O\fP PCRE_NO_AUTO_POSSESS 393 \fB/U\fP PCRE_UNGREEDY 394 \fB/W\fP PCRE_UCP 395 \fB/X\fP PCRE_EXTRA 396 \fB/Y\fP PCRE_NO_START_OPTIMIZE 397 \fB/\fP PCRE_NEWLINE_ANY 398 \fB/\fP PCRE_NEWLINE_ANYCRLF 399 \fB/\fP PCRE_NEWLINE_CR 400 \fB/\fP PCRE_NEWLINE_CRLF 401 \fB/\fP PCRE_NEWLINE_LF 402 \fB/\fP PCRE_BSR_ANYCRLF 403 \fB/\fP PCRE_BSR_UNICODE 404 \fB/\fP PCRE_JAVASCRIPT_COMPAT 405 .sp 406 The modifiers that are enclosed in angle brackets are literal strings as shown, 407 including the angle brackets, but the letters within can be in either case. 408 This example sets multiline matching with CRLF as the line ending sequence: 409 .sp 410 /^abc/m 411 .sp 412 As well as turning on the PCRE_UTF8/16/32 option, the \fB/8\fP modifier causes 413 all non-printing characters in output strings to be printed using the 414 \ex{hh...} notation. Otherwise, those less than 0x100 are output in hex without 415 the curly brackets. 416 .P 417 Full details of the PCRE options are given in the 418 .\" HREF 419 \fBpcreapi\fP 420 .\" 421 documentation. 422 . 423 . 424 .SS "Finding all matches in a string" 425 .rs 426 .sp 427 Searching for all possible matches within each subject string can be requested 428 by the \fB/g\fP or \fB/G\fP modifier. After finding a match, PCRE is called 429 again to search the remainder of the subject string. The difference between 430 \fB/g\fP and \fB/G\fP is that the former uses the \fIstartoffset\fP argument to 431 \fBpcre[16|32]_exec()\fP to start searching at a new point within the entire 432 string (which is in effect what Perl does), whereas the latter passes over a 433 shortened substring. This makes a difference to the matching process if the 434 pattern begins with a lookbehind assertion (including \eb or \eB). 435 .P 436 If any call to \fBpcre[16|32]_exec()\fP in a \fB/g\fP or \fB/G\fP sequence matches 437 an empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and 438 PCRE_ANCHORED flags set in order to search for another, non-empty, match at the 439 same point. If this second match fails, the start offset is advanced, and the 440 normal match is retried. This imitates the way Perl handles such cases when 441 using the \fB/g\fP modifier or the \fBsplit()\fP function. Normally, the start 442 offset is advanced by one character, but if the newline convention recognizes 443 CRLF as a newline, and the current character is CR followed by LF, an advance 444 of two is used. 445 . 446 . 447 .SS "Other modifiers" 448 .rs 449 .sp 450 There are yet more modifiers for controlling the way \fBpcretest\fP 451 operates. 452 .P 453 The \fB/+\fP modifier requests that as well as outputting the substring that 454 matched the entire pattern, \fBpcretest\fP should in addition output the 455 remainder of the subject string. This is useful for tests where the subject 456 contains multiple copies of the same substring. If the \fB+\fP modifier appears 457 twice, the same action is taken for captured substrings. In each case the 458 remainder is output on the following line with a plus character following the 459 capture number. Note that this modifier must not immediately follow the /S 460 modifier because /S+ and /S++ have other meanings. 461 .P 462 The \fB/=\fP modifier requests that the values of all potential captured 463 parentheses be output after a match. By default, only those up to the highest 464 one actually used in the match are output (corresponding to the return code 465 from \fBpcre[16|32]_exec()\fP). Values in the offsets vector corresponding to 466 higher numbers should be set to -1, and these are output as "". This 467 modifier gives a way of checking that this is happening. 468 .P 469 The \fB/B\fP modifier is a debugging feature. It requests that \fBpcretest\fP 470 output a representation of the compiled code after compilation. Normally this 471 information contains length and offset values; however, if \fB/Z\fP is also 472 present, this data is replaced by spaces. This is a special feature for use in 473 the automatic test scripts; it ensures that the same output is generated for 474 different internal link sizes. 475 .P 476 The \fB/D\fP modifier is a PCRE debugging feature, and is equivalent to 477 \fB/BI\fP, that is, both the \fB/B\fP and the \fB/I\fP modifiers. 478 .P 479 The \fB/F\fP modifier causes \fBpcretest\fP to flip the byte order of the 480 2-byte and 4-byte fields in the compiled pattern. This facility is for testing 481 the feature in PCRE that allows it to execute patterns that were compiled on a 482 host with a different endianness. This feature is not available when the POSIX 483 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is 484 specified. See also the section about saving and reloading compiled patterns 485 below. 486 .P 487 The \fB/I\fP modifier requests that \fBpcretest\fP output information about the 488 compiled pattern (whether it is anchored, has a fixed first character, and 489 so on). It does this by calling \fBpcre[16|32]_fullinfo()\fP after compiling a 490 pattern. If the pattern is studied, the results of that are also output. In 491 this output, the word "char" means a non-UTF character, that is, the value of a 492 single data item (8-bit, 16-bit, or 32-bit, depending on the library that is 493 being tested). 494 .P 495 The \fB/K\fP modifier requests \fBpcretest\fP to show names from backtracking 496 control verbs that are returned from calls to \fBpcre[16|32]_exec()\fP. It causes 497 \fBpcretest\fP to create a \fBpcre[16|32]_extra\fP block if one has not already 498 been created by a call to \fBpcre[16|32]_study()\fP, and to set the 499 PCRE_EXTRA_MARK flag and the \fBmark\fP field within it, every time that 500 \fBpcre[16|32]_exec()\fP is called. If the variable that the \fBmark\fP field 501 points to is non-NULL for a match, non-match, or partial match, \fBpcretest\fP 502 prints the string to which it points. For a match, this is shown on a line by 503 itself, tagged with "MK:". For a non-match it is added to the message. 504 .P 505 The \fB/L\fP modifier must be followed directly by the name of a locale, for 506 example, 507 .sp 508 /pattern/Lfr_FR 509 .sp 510 For this reason, it must be the last modifier. The given locale is set, 511 \fBpcre[16|32]_maketables()\fP is called to build a set of character tables for 512 the locale, and this is then passed to \fBpcre[16|32]_compile()\fP when compiling 513 the regular expression. Without an \fB/L\fP (or \fB/T\fP) modifier, NULL is 514 passed as the tables pointer; that is, \fB/L\fP applies only to the expression 515 on which it appears. 516 .P 517 The \fB/M\fP modifier causes the size in bytes of the memory block used to hold 518 the compiled pattern to be output. This does not include the size of the 519 \fBpcre[16|32]\fP block; it is just the actual compiled data. If the pattern is 520 successfully studied with the PCRE_STUDY_JIT_COMPILE option, the size of the 521 JIT compiled code is also output. 522 .P 523 The \fB/Q\fP modifier is used to test the use of \fBpcre_stack_guard\fP. It 524 must be followed by '0' or '1', specifying the return code to be given from an 525 external function that is passed to PCRE and used for stack checking during 526 compilation (see the 527 .\" HREF 528 \fBpcreapi\fP 529 .\" 530 documentation for details). 531 .P 532 The \fB/S\fP modifier causes \fBpcre[16|32]_study()\fP to be called after the 533 expression has been compiled, and the results used when the expression is 534 matched. There are a number of qualifying characters that may follow \fB/S\fP. 535 They may appear in any order. 536 .P 537 If \fB/S\fP is followed by an exclamation mark, \fBpcre[16|32]_study()\fP is 538 called with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a 539 \fBpcre_extra\fP block, even when studying discovers no useful information. 540 .P 541 If \fB/S\fP is followed by a second S character, it suppresses studying, even 542 if it was requested externally by the \fB-s\fP command line option. This makes 543 it possible to specify that certain patterns are always studied, and others are 544 never studied, independently of \fB-s\fP. This feature is used in the test 545 files in a few cases where the output is different when the pattern is studied. 546 .P 547 If the \fB/S\fP modifier is followed by a + character, the call to 548 \fBpcre[16|32]_study()\fP is made with all the JIT study options, requesting 549 just-in-time optimization support if it is available, for both normal and 550 partial matching. If you want to restrict the JIT compiling modes, you can 551 follow \fB/S+\fP with a digit in the range 1 to 7: 552 .sp 553 1 normal match only 554 2 soft partial match only 555 3 normal match and soft partial match 556 4 hard partial match only 557 6 soft and hard partial match 558 7 all three modes (default) 559 .sp 560 If \fB/S++\fP is used instead of \fB/S+\fP (with or without a following digit), 561 the text "(JIT)" is added to the first output line after a match or no match 562 when JIT-compiled code was actually used. 563 .P 564 Note that there is also an independent \fB/+\fP modifier; it must not be given 565 immediately after \fB/S\fP or \fB/S+\fP because this will be misinterpreted. 566 .P 567 If JIT studying is successful, the compiled JIT code will automatically be used 568 when \fBpcre[16|32]_exec()\fP is run, except when incompatible run-time options 569 are specified. For more details, see the 570 .\" HREF 571 \fBpcrejit\fP 572 .\" 573 documentation. See also the \fB\eJ\fP escape sequence below for a way of 574 setting the size of the JIT stack. 575 .P 576 Finally, if \fB/S\fP is followed by a minus character, JIT compilation is 577 suppressed, even if it was requested externally by the \fB-s\fP command line 578 option. This makes it possible to specify that JIT is never to be used for 579 certain patterns. 580 .P 581 The \fB/T\fP modifier must be followed by a single digit. It causes a specific 582 set of built-in character tables to be passed to \fBpcre[16|32]_compile()\fP. It 583 is used in the standard PCRE tests to check behaviour with different character 584 tables. The digit specifies the tables as follows: 585 .sp 586 0 the default ASCII tables, as distributed in 587 pcre_chartables.c.dist 588 1 a set of tables defining ISO 8859 characters 589 .sp 590 In table 1, some characters whose codes are greater than 128 are identified as 591 letters, digits, spaces, etc. 592 . 593 . 594 .SS "Using the POSIX wrapper API" 595 .rs 596 .sp 597 The \fB/P\fP modifier causes \fBpcretest\fP to call PCRE via the POSIX wrapper 598 API rather than its native API. This supports only the 8-bit library. When 599 \fB/P\fP is set, the following modifiers set options for the \fBregcomp()\fP 600 function: 601 .sp 602 /i REG_ICASE 603 /m REG_NEWLINE 604 /N REG_NOSUB 605 /s REG_DOTALL ) 606 /U REG_UNGREEDY ) These options are not part of 607 /W REG_UCP ) the POSIX standard 608 /8 REG_UTF8 ) 609 .sp 610 The \fB/+\fP modifier works as described above. All other modifiers are 611 ignored. 612 . 613 . 614 .SS "Locking out certain modifiers" 615 .rs 616 .sp 617 PCRE can be compiled with or without support for certain features such as 618 UTF-8/16/32 or Unicode properties. Accordingly, the standard tests are split up 619 into a number of different files that are selected for running depending on 620 which features are available. When updating the tests, it is all too easy to 621 put a new test into the wrong file by mistake; for example, to put a test that 622 requires UTF support into a file that is used when it is not available. To help 623 detect such mistakes as early as possible, there is a facility for locking out 624 specific modifiers. If an input line for \fBpcretest\fP starts with the string 625 "< forbid " the following sequence of characters is taken as a list of 626 forbidden modifiers. For example, in the test files that must not use UTF or 627 Unicode property support, this line appears: 628 .sp 629 < forbid 8W 630 .sp 631 This locks out the /8 and /W modifiers. An immediate error is given if they are 632 subsequently encountered. If the character string contains < but not >, all the 633 multi-character modifiers that begin with < are locked out. Otherwise, such 634 modifiers must be explicitly listed, for example: 635 .sp 636 < forbid 637 .sp 638 There must be a single space between < and "forbid" for this feature to be 639 recognised. If there is not, the line is interpreted either as a request to 640 re-load a pre-compiled pattern (see "SAVING AND RELOADING COMPILED PATTERNS" 641 below) or, if there is a another < character, as a pattern that uses < as its 642 delimiter. 643 . 644 . 645 .SH "DATA LINES" 646 .rs 647 .sp 648 Before each data line is passed to \fBpcre[16|32]_exec()\fP, leading and trailing 649 white space is removed, and it is then scanned for \e escapes. Some of these 650 are pretty esoteric features, intended for checking out some of the more 651 complicated features of PCRE. If you are just testing "ordinary" regular 652 expressions, you probably don't need any of these. The following escapes are 653 recognized: 654 .sp 655 \ea alarm (BEL, \ex07) 656 \eb backspace (\ex08) 657 \ee escape (\ex27) 658 \ef form feed (\ex0c) 659 \en newline (\ex0a) 660 .\" JOIN 661 \eqdd set the PCRE_MATCH_LIMIT limit to dd 662 (any number of digits) 663 \er carriage return (\ex0d) 664 \et tab (\ex09) 665 \ev vertical tab (\ex0b) 666 \ennn octal character (up to 3 octal digits); always 667 a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode 668 \eo{dd...} octal character (any number of octal digits} 669 \exhh hexadecimal byte (up to 2 hex digits) 670 \ex{hh...} hexadecimal character (any number of hex digits) 671 .\" JOIN 672 \eA pass the PCRE_ANCHORED option to \fBpcre[16|32]_exec()\fP 673 or \fBpcre[16|32]_dfa_exec()\fP 674 .\" JOIN 675 \eB pass the PCRE_NOTBOL option to \fBpcre[16|32]_exec()\fP 676 or \fBpcre[16|32]_dfa_exec()\fP 677 .\" JOIN 678 \eCdd call pcre[16|32]_copy_substring() for substring dd 679 after a successful match (number less than 32) 680 .\" JOIN 681 \eCname call pcre[16|32]_copy_named_substring() for substring 682 "name" after a successful match (name termin- 683 ated by next non alphanumeric character) 684 .\" JOIN 685 \eC+ show the current captured substrings at callout 686 time 687 \eC- do not supply a callout function 688 .\" JOIN 689 \eC!n return 1 instead of 0 when callout number n is 690 reached 691 .\" JOIN 692 \eC!n!m return 1 instead of 0 when callout number n is 693 reached for the nth time 694 .\" JOIN 695 \eC*n pass the number n (may be negative) as callout 696 data; this is used as the callout return value 697 \eD use the \fBpcre[16|32]_dfa_exec()\fP match function 698 \eF only shortest match for \fBpcre[16|32]_dfa_exec()\fP 699 .\" JOIN 700 \eGdd call pcre[16|32]_get_substring() for substring dd 701 after a successful match (number less than 32) 702 .\" JOIN 703 \eGname call pcre[16|32]_get_named_substring() for substring 704 "name" after a successful match (name termin- 705 ated by next non-alphanumeric character) 706 .\" JOIN 707 \eJdd set up a JIT stack of dd kilobytes maximum (any 708 number of digits) 709 .\" JOIN 710 \eL call pcre[16|32]_get_substringlist() after a 711 successful match 712 .\" JOIN 713 \eM discover the minimum MATCH_LIMIT and 714 MATCH_LIMIT_RECURSION settings 715 .\" JOIN 716 \eN pass the PCRE_NOTEMPTY option to \fBpcre[16|32]_exec()\fP 717 or \fBpcre[16|32]_dfa_exec()\fP; if used twice, pass the 718 PCRE_NOTEMPTY_ATSTART option 719 .\" JOIN 720 \eOdd set the size of the output vector passed to 721 \fBpcre[16|32]_exec()\fP to dd (any number of digits) 722 .\" JOIN 723 \eP pass the PCRE_PARTIAL_SOFT option to \fBpcre[16|32]_exec()\fP 724 or \fBpcre[16|32]_dfa_exec()\fP; if used twice, pass the 725 PCRE_PARTIAL_HARD option 726 .\" JOIN 727 \eQdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd 728 (any number of digits) 729 \eR pass the PCRE_DFA_RESTART option to \fBpcre[16|32]_dfa_exec()\fP 730 \eS output details of memory get/free calls during matching 731 .\" JOIN 732 \eY pass the PCRE_NO_START_OPTIMIZE option to \fBpcre[16|32]_exec()\fP 733 or \fBpcre[16|32]_dfa_exec()\fP 734 .\" JOIN 735 \eZ pass the PCRE_NOTEOL option to \fBpcre[16|32]_exec()\fP 736 or \fBpcre[16|32]_dfa_exec()\fP 737 .\" JOIN 738 \e? pass the PCRE_NO_UTF[8|16|32]_CHECK option to 739 \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP 740 .\" JOIN 741 \e>dd start the match at offset dd (optional "-"; then 742 any number of digits); this sets the \fIstartoffset\fP 743 argument for \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP 744 .\" JOIN 745 \e pass the PCRE_NEWLINE_CR option to \fBpcre[16|32]_exec()\fP 746 or \fBpcre[16|32]_dfa_exec()\fP 747 .\" JOIN 748 \e pass the PCRE_NEWLINE_LF option to \fBpcre[16|32]_exec()\fP 749 or \fBpcre[16|32]_dfa_exec()\fP 750 .\" JOIN 751 \e pass the PCRE_NEWLINE_CRLF option to \fBpcre[16|32]_exec()\fP 752 or \fBpcre[16|32]_dfa_exec()\fP 753 .\" JOIN 754 \e pass the PCRE_NEWLINE_ANYCRLF option to \fBpcre[16|32]_exec()\fP 755 or \fBpcre[16|32]_dfa_exec()\fP 756 .\" JOIN 757 \e pass the PCRE_NEWLINE_ANY option to \fBpcre[16|32]_exec()\fP 758 or \fBpcre[16|32]_dfa_exec()\fP 759 .sp 760 The use of \ex{hh...} is not dependent on the use of the \fB/8\fP modifier on 761 the pattern. It is recognized always. There may be any number of hexadecimal 762 digits inside the braces; invalid values provoke error messages. 763 .P 764 Note that \exhh specifies one byte rather than one character in UTF-8 mode; 765 this makes it possible to construct invalid UTF-8 sequences for testing 766 purposes. On the other hand, \ex{hh} is interpreted as a UTF-8 character in 767 UTF-8 mode, generating more than one byte if the value is greater than 127. 768 When testing the 8-bit library not in UTF-8 mode, \ex{hh} generates one byte 769 for values less than 256, and causes an error for greater values. 770 .P 771 In UTF-16 mode, all 4-digit \ex{hhhh} values are accepted. This makes it 772 possible to construct invalid UTF-16 sequences for testing purposes. 773 .P 774 In UTF-32 mode, all 4- to 8-digit \ex{...} values are accepted. This makes it 775 possible to construct invalid UTF-32 sequences for testing purposes. 776 .P 777 The escapes that specify line ending sequences are literal strings, exactly as 778 shown. No more than one newline setting should be present in any data line. 779 .P 780 A backslash followed by anything else just escapes the anything else. If 781 the very last character is a backslash, it is ignored. This gives a way of 782 passing an empty line as data, since a real empty line terminates the data 783 input. 784 .P 785 The \fB\eJ\fP escape provides a way of setting the maximum stack size that is 786 used by the just-in-time optimization code. It is ignored if JIT optimization 787 is not being used. Providing a stack that is larger than the default 32K is 788 necessary only for very complicated patterns. 789 .P 790 If \eM is present, \fBpcretest\fP calls \fBpcre[16|32]_exec()\fP several times, 791 with different values in the \fImatch_limit\fP and \fImatch_limit_recursion\fP 792 fields of the \fBpcre[16|32]_extra\fP data structure, until it finds the minimum 793 numbers for each parameter that allow \fBpcre[16|32]_exec()\fP to complete without 794 error. Because this is testing a specific feature of the normal interpretive 795 \fBpcre[16|32]_exec()\fP execution, the use of any JIT optimization that might 796 have been set up by the \fB/S+\fP qualifier of \fB-s+\fP option is disabled. 797 .P 798 The \fImatch_limit\fP number is a measure of the amount of backtracking 799 that takes place, and checking it out can be instructive. For most simple 800 matches, the number is quite small, but for patterns with very large numbers of 801 matching possibilities, it can become large very quickly with increasing length 802 of subject string. The \fImatch_limit_recursion\fP number is a measure of how 803 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is 804 needed to complete the match attempt. 805 .P 806 When \eO is used, the value specified may be higher or lower than the size set 807 by the \fB-O\fP command line option (or defaulted to 45); \eO applies only to 808 the call of \fBpcre[16|32]_exec()\fP for the line in which it appears. 809 .P 810 If the \fB/P\fP modifier was present on the pattern, causing the POSIX wrapper 811 API to be used, the only option-setting sequences that have any effect are \eB, 812 \eN, and \eZ, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively, 813 to be passed to \fBregexec()\fP. 814 . 815 . 816 .SH "THE ALTERNATIVE MATCHING FUNCTION" 817 .rs 818 .sp 819 By default, \fBpcretest\fP uses the standard PCRE matching function, 820 \fBpcre[16|32]_exec()\fP to match each data line. PCRE also supports an 821 alternative matching function, \fBpcre[16|32]_dfa_test()\fP, which operates in a 822 different way, and has some restrictions. The differences between the two 823 functions are described in the 824 .\" HREF 825 \fBpcrematching\fP 826 .\" 827 documentation. 828 .P 829 If a data line contains the \eD escape sequence, or if the command line 830 contains the \fB-dfa\fP option, the alternative matching function is used. 831 This function finds all possible matches at a given point. If, however, the \eF 832 escape sequence is present in the data line, it stops after the first match is 833 found. This is always the shortest possible match. 834 . 835 . 836 .SH "DEFAULT OUTPUT FROM PCRETEST" 837 .rs 838 .sp 839 This section describes the output when the normal matching function, 840 \fBpcre[16|32]_exec()\fP, is being used. 841 .P 842 When a match succeeds, \fBpcretest\fP outputs the list of captured substrings 843 that \fBpcre[16|32]_exec()\fP returns, starting with number 0 for the string that 844 matched the whole pattern. Otherwise, it outputs "No match" when the return is 845 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching 846 substring when \fBpcre[16|32]_exec()\fP returns PCRE_ERROR_PARTIAL. (Note that 847 this is the entire substring that was inspected during the partial match; it 848 may include characters before the actual match start if a lookbehind assertion, 849 \eK, \eb, or \eB was involved.) For any other return, \fBpcretest\fP outputs 850 the PCRE negative error number and a short descriptive phrase. If the error is 851 a failed UTF string check, the offset of the start of the failing character and 852 the reason code are also output, provided that the size of the output vector is 853 at least two. Here is an example of an interactive \fBpcretest\fP run. 854 .sp 855 $pcretest 856 PCRE version 8.13 2011-04-30 857 .sp 858 re> /^abc(\ed+)/ 859 data> abc123 860 0: abc123 861 1: 123 862 data> xyz 863 No match 864 .sp 865 Unset capturing substrings that are not followed by one that is set are not 866 returned by \fBpcre[16|32]_exec()\fP, and are not shown by \fBpcretest\fP. In the 867 following example, there are two capturing substrings, but when the first data 868 line is matched, the second, unset substring is not shown. An "internal" unset 869 substring is shown as "", as for the second data line. 870 .sp 871 re> /(a)|(b)/ 872 data> a 873 0: a 874 1: a 875 data> b 876 0: b 877 1: 878 2: b 879 .sp 880 If the strings contain any non-printing characters, they are output as \exhh 881 escapes if the value is less than 256 and UTF mode is not set. Otherwise they 882 are output as \ex{hh...} escapes. See below for the definition of non-printing 883 characters. If the pattern has the \fB/+\fP modifier, the output for substring 884 0 is followed by the the rest of the subject string, identified by "0+" like 885 this: 886 .sp 887 re> /cat/+ 888 data> cataract 889 0: cat 890 0+ aract 891 .sp 892 If the pattern has the \fB/g\fP or \fB/G\fP modifier, the results of successive 893 matching attempts are output in sequence, like this: 894 .sp 895 re> /\eBi(\ew\ew)/g 896 data> Mississippi 897 0: iss 898 1: ss 899 0: iss 900 1: ss 901 0: ipp 902 1: pp 903 .sp 904 "No match" is output only if the first match attempt fails. Here is an example 905 of a failure message (the offset 4 that is specified by \e>4 is past the end of 906 the subject string): 907 .sp 908 re> /xyz/ 909 data> xyz\e>4 910 Error -24 (bad offset value) 911 .P 912 If any of the sequences \fB\eC\fP, \fB\eG\fP, or \fB\eL\fP are present in a 913 data line that is successfully matched, the substrings extracted by the 914 convenience functions are output with C, G, or L after the string number 915 instead of a colon. This is in addition to the normal full list. The string 916 length (that is, the return from the extraction function) is given in 917 parentheses after each string for \fB\eC\fP and \fB\eG\fP. 918 .P 919 Note that whereas patterns can be continued over several lines (a plain ">" 920 prompt is used for continuations), data lines may not. However newlines can be 921 included in data by means of the \en escape (or \er, \er\en, etc., depending on 922 the newline sequence setting). 923 . 924 . 925 . 926 .SH "OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION" 927 .rs 928 .sp 929 When the alternative matching function, \fBpcre[16|32]_dfa_exec()\fP, is used (by 930 means of the \eD escape sequence or the \fB-dfa\fP command line option), the 931 output consists of a list of all the matches that start at the first point in 932 the subject where there is at least one match. For example: 933 .sp 934 re> /(tang|tangerine|tan)/ 935 data> yellow tangerine\eD 936 0: tangerine 937 1: tang 938 2: tan 939 .sp 940 (Using the normal matching function on this data finds only "tang".) The 941 longest matching string is always given first (and numbered zero). After a 942 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the 943 partially matching substring. (Note that this is the entire substring that was 944 inspected during the partial match; it may include characters before the actual 945 match start if a lookbehind assertion, \eK, \eb, or \eB was involved.) 946 .P 947 If \fB/g\fP is present on the pattern, the search for further matches resumes 948 at the end of the longest match. For example: 949 .sp 950 re> /(tang|tangerine|tan)/g 951 data> yellow tangerine and tangy sultana\eD 952 0: tangerine 953 1: tang 954 2: tan 955 0: tang 956 1: tan 957 0: tan 958 .sp 959 Since the matching function does not support substring capture, the escape 960 sequences that are concerned with captured substrings are not relevant. 961 . 962 . 963 .SH "RESTARTING AFTER A PARTIAL MATCH" 964 .rs 965 .sp 966 When the alternative matching function has given the PCRE_ERROR_PARTIAL return, 967 indicating that the subject partially matched the pattern, you can restart the 968 match with additional subject data by means of the \eR escape sequence. For 969 example: 970 .sp 971 re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/ 972 data> 23ja\eP\eD 973 Partial match: 23ja 974 data> n05\eR\eD 975 0: n05 976 .sp 977 For further information about partial matching, see the 978 .\" HREF 979 \fBpcrepartial\fP 980 .\" 981 documentation. 982 . 983 . 984 .SH CALLOUTS 985 .rs 986 .sp 987 If the pattern contains any callout requests, \fBpcretest\fP's callout function 988 is called during matching. This works with both matching functions. By default, 989 the called function displays the callout number, the start and current 990 positions in the text at the callout time, and the next pattern item to be 991 tested. For example: 992 .sp 993 --->pqrabcdef 994 0 ^ ^ \ed 995 .sp 996 This output indicates that callout number 0 occurred for a match attempt 997 starting at the fourth character of the subject string, when the pointer was at 998 the seventh character of the data, and when the next pattern item was \ed. Just 999 one circumflex is output if the start and current positions are the same. 1000 .P 1001 Callouts numbered 255 are assumed to be automatic callouts, inserted as a 1002 result of the \fB/C\fP pattern modifier. In this case, instead of showing the 1003 callout number, the offset in the pattern, preceded by a plus, is output. For 1004 example: 1005 .sp 1006 re> /\ed?[A-E]\e*/C 1007 data> E* 1008 --->E* 1009 +0 ^ \ed? 1010 +3 ^ [A-E] 1011 +8 ^^ \e* 1012 +10 ^ ^ 1013 0: E* 1014 .sp 1015 If a pattern contains (*MARK) items, an additional line is output whenever 1016 a change of latest mark is passed to the callout function. For example: 1017 .sp 1018 re> /a(*MARK:X)bc/C 1019 data> abc 1020 --->abc 1021 +0 ^ a 1022 +1 ^^ (*MARK:X) 1023 +10 ^^ b 1024 Latest Mark: X 1025 +11 ^ ^ c 1026 +12 ^ ^ 1027 0: abc 1028 .sp 1029 The mark changes between matching "a" and "b", but stays the same for the rest 1030 of the match, so nothing more is output. If, as a result of backtracking, the 1031 mark reverts to being unset, the text "" is output. 1032 .P 1033 The callout function in \fBpcretest\fP returns zero (carry on matching) by 1034 default, but you can use a \eC item in a data line (as described above) to 1035 change this and other parameters of the callout. 1036 .P 1037 Inserting callouts can be helpful when using \fBpcretest\fP to check 1038 complicated regular expressions. For further information about callouts, see 1039 the 1040 .\" HREF 1041 \fBpcrecallout\fP 1042 .\" 1043 documentation. 1044 . 1045 . 1046 . 1047 .SH "NON-PRINTING CHARACTERS" 1048 .rs 1049 .sp 1050 When \fBpcretest\fP is outputting text in the compiled version of a pattern, 1051 bytes other than 32-126 are always treated as non-printing characters are are 1052 therefore shown as hex escapes. 1053 .P 1054 When \fBpcretest\fP is outputting text that is a matched part of a subject 1055 string, it behaves in the same way, unless a different locale has been set for 1056 the pattern (using the \fB/L\fP modifier). In this case, the \fBisprint()\fP 1057 function to distinguish printing and non-printing characters. 1058 . 1059 . 1060 . 1061 .SH "SAVING AND RELOADING COMPILED PATTERNS" 1062 .rs 1063 .sp 1064 The facilities described in this section are not available when the POSIX 1065 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is 1066 specified. 1067 .P 1068 When the POSIX interface is not in use, you can cause \fBpcretest\fP to write a 1069 compiled pattern to a file, by following the modifiers with > and a file name. 1070 For example: 1071 .sp 1072 /pattern/im >/some/file 1073 .sp 1074 See the 1075 .\" HREF 1076 \fBpcreprecompile\fP 1077 .\" 1078 documentation for a discussion about saving and re-using compiled patterns. 1079 Note that if the pattern was successfully studied with JIT optimization, the 1080 JIT data cannot be saved. 1081 .P 1082 The data that is written is binary. The first eight bytes are the length of the 1083 compiled pattern data followed by the length of the optional study data, each 1084 written as four bytes in big-endian order (most significant byte first). If 1085 there is no study data (either the pattern was not studied, or studying did not 1086 return any data), the second length is zero. The lengths are followed by an 1087 exact copy of the compiled pattern. If there is additional study data, this 1088 (excluding any JIT data) follows immediately after the compiled pattern. After 1089 writing the file, \fBpcretest\fP expects to read a new pattern. 1090 .P 1091 A saved pattern can be reloaded into \fBpcretest\fP by specifying < and a file 1092 name instead of a pattern. There must be no space between < and the file name, 1093 which must not contain a < character, as otherwise \fBpcretest\fP will 1094 interpret the line as a pattern delimited by < characters. For example: 1095 .sp 1096 re>