1<html> 2<head> 3<title>pcre2test specification</title> 4</head> 5<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> 6<h1>pcre2test man page</h1> 7<p> 8Return to the <a href="index.html">PCRE2 index page</a>. 9</p> 10<p> 11This page is part of the PCRE2 HTML documentation. It was generated 12automatically from the original man page. If there is any nonsense in it, 13please consult the 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">PCRE2's 8-BIT, 16-BIT AND 32-BIT LIBRARIES</a> 18<li><a name="TOC3" href="#SEC3">INPUT ENCODING</a> 19<li><a name="TOC4" href="#SEC4">COMMAND LINE OPTIONS</a> 20<li><a name="TOC5" href="#SEC5">DESCRIPTION</a> 21<li><a name="TOC6" href="#SEC6">COMMAND LINES</a> 22<li><a name="TOC7" href="#SEC7">MODIFIER SYNTAX</a> 23<li><a name="TOC8" href="#SEC8">PATTERN SYNTAX</a> 24<li><a name="TOC9" href="#SEC9">SUBJECT LINE SYNTAX</a> 25<li><a name="TOC10" href="#SEC10">PATTERN MODIFIERS</a> 26<li><a name="TOC11" href="#SEC11">SUBJECT MODIFIERS</a> 27<li><a name="TOC12" href="#SEC12">THE ALTERNATIVE MATCHING FUNCTION</a> 28<li><a name="TOC13" href="#SEC13">DEFAULT OUTPUT FROM pcre2test</a> 29<li><a name="TOC14" href="#SEC14">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a> 30<li><a name="TOC15" href="#SEC15">RESTARTING AFTER A PARTIAL MATCH</a> 31<li><a name="TOC16" href="#SEC16">CALLOUTS</a> 32<li><a name="TOC17" href="#SEC17">NON-PRINTING CHARACTERS</a> 33<li><a name="TOC18" href="#SEC18">SAVING AND RESTORING COMPILED PATTERNS</a> 34<li><a name="TOC19" href="#SEC19">SEE ALSO</a> 35<li><a name="TOC20" href="#SEC20">AUTHOR</a> 36<li><a name="TOC21" href="#SEC21">REVISION</a> 37</ul> 38<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> 39<P> 40<b>pcre2test [options] [input file [output file]]</b> 41<br> 42<br> 43<b>pcre2test</b> is a test program for the PCRE2 regular expression libraries, 44but it can also be used for experimenting with regular expressions. This 45document describes the features of the test program; for details of the regular 46expressions themselves, see the 47<a href="pcre2pattern.html"><b>pcre2pattern</b></a> 48documentation. For details of the PCRE2 library function calls and their 49options, see the 50<a href="pcre2api.html"><b>pcre2api</b></a> 51documentation. 52</P> 53<P> 54The input for <b>pcre2test</b> is a sequence of regular expression patterns and 55subject strings to be matched. There are also command lines for setting 56defaults and controlling some special actions. The output shows the result of 57each match attempt. Modifiers on external or internal command lines, the 58patterns, and the subject lines specify PCRE2 function options, control how the 59subject is processed, and what output is produced. 60</P> 61<P> 62As the original fairly simple PCRE library evolved, it acquired many different 63features, and as a result, the original <b>pcretest</b> program ended up with a 64lot of options in a messy, arcane syntax for testing all the features. The 65move to the new PCRE2 API provided an opportunity to re-implement the test 66program as <b>pcre2test</b>, with a cleaner modifier syntax. Nevertheless, there 67are still many obscure modifiers, some of which are specifically designed for 68use in conjunction with the test script and data files that are distributed as 69part of PCRE2. All the modifiers are documented here, some without much 70justification, but many of them are unlikely to be of use except when testing 71the libraries. 72</P> 73<br><a name="SEC2" href="#TOC1">PCRE2's 8-BIT, 16-BIT AND 32-BIT LIBRARIES</a><br> 74<P> 75Different versions of the PCRE2 library can be built to support character 76strings that are encoded in 8-bit, 16-bit, or 32-bit code units. One, two, or 77all three of these libraries may be simultaneously installed. The 78<b>pcre2test</b> program can be used to test all the libraries. However, its own 79input and output are always in 8-bit format. When testing the 16-bit or 32-bit 80libraries, patterns and subject strings are converted to 16-bit or 32-bit 81format before being passed to the library functions. Results are converted back 82to 8-bit code units for output. 83</P> 84<P> 85In the rest of this document, the names of library functions and structures 86are given in generic form, for example, <b>pcre_compile()</b>. The actual 87names used in the libraries have a suffix _8, _16, or _32, as appropriate. 88<a name="inputencoding"></a></P> 89<br><a name="SEC3" href="#TOC1">INPUT ENCODING</a><br> 90<P> 91Input to <b>pcre2test</b> is processed line by line, either by calling the C 92library's <b>fgets()</b> function, or via the <b>libreadline</b> library. In some 93Windows environments character 26 (hex 1A) causes an immediate end of file, and 94no further data is read, so this character should be avoided unless you really 95want that action. 96</P> 97<P> 98The input is processed using using C's string functions, so must not 99contain binary zeros, even though in Unix-like environments, <b>fgets()</b> 100treats any bytes other than newline as data characters. An error is generated 101if a binary zero is encountered. By default subject lines are processed for 102backslash escapes, which makes it possible to include any data value in strings 103that are passed to the library for matching. For patterns, there is a facility 104for specifying some or all of the 8-bit input characters as hexadecimal pairs, 105which makes it possible to include binary zeros. 106</P> 107<br><b> 108Input for the 16-bit and 32-bit libraries 109</b><br> 110<P> 111When testing the 16-bit or 32-bit libraries, there is a need to be able to 112generate character code points greater than 255 in the strings that are passed 113to the library. For subject lines, backslash escapes can be used. In addition, 114when the <b>utf</b> modifier (see 115<a href="#optionmodifiers">"Setting compilation options"</a> 116below) is set, the pattern and any following subject lines are interpreted as 117UTF-8 strings and translated to UTF-16 or UTF-32 as appropriate. 118</P> 119<P> 120For non-UTF testing of wide characters, the <b>utf8_input</b> modifier can be 121used. This is mutually exclusive with <b>utf</b>, and is allowed only in 16-bit 122or 32-bit mode. It causes the pattern and following subject lines to be treated 123as UTF-8 according to the original definition (RFC 2279), which allows for 124character values up to 0x7fffffff. Each character is placed in one 16-bit or 12532-bit code unit (in the 16-bit case, values greater than 0xffff cause an error 126to occur). 127</P> 128<P> 129UTF-8 (in its original definition) is not capable of encoding values greater 130than 0x7fffffff, but such values can be handled by the 32-bit library. When 131testing this library in non-UTF mode with <b>utf8_input</b> set, if any 132character is preceded by the byte 0xff (which is an invalid byte in UTF-8) 1330x80000000 is added to the character's value. This is the only way of passing 134such code points in a pattern string. For subject strings, using an escape 135sequence is preferable. 136</P> 137<br><a name="SEC4" href="#TOC1">COMMAND LINE OPTIONS</a><br> 138<P> 139<b>-8</b> 140If the 8-bit library has been built, this option causes it to be used (this is 141the default). If the 8-bit library has not been built, this option causes an 142error. 143</P> 144<P> 145<b>-16</b> 146If the 16-bit library has been built, this option causes it to be used. If only 147the 16-bit library has been built, this is the default. If the 16-bit library 148has not been built, this option causes an error. 149</P> 150<P> 151<b>-32</b> 152If the 32-bit library has been built, this option causes it to be used. If only 153the 32-bit library has been built, this is the default. If the 32-bit library 154has not been built, this option causes an error. 155</P> 156<P> 157<b>-ac</b> 158Behave as if each pattern has the <b>auto_callout</b> modifier, that is, insert 159automatic callouts into every pattern that is compiled. 160</P> 161<P> 162<b>-AC</b> 163As for <b>-ac</b>, but in addition behave as if each subject line has the 164<b>callout_extra</b> modifier, that is, show additional information from 165callouts. 166</P> 167<P> 168<b>-b</b> 169Behave as if each pattern has the <b>fullbincode</b> modifier; the full 170internal binary form of the pattern is output after compilation. 171</P> 172<P> 173<b>-C</b> 174Output the version number of the PCRE2 library, and all available information 175about the optional features that are included, and then exit with zero exit 176code. All other options are ignored. If both -C and -LM are present, whichever 177is first is recognized. 178</P> 179<P> 180<b>-C</b> <i>option</i> 181Output information about a specific build-time option, then exit. This 182functionality is intended for use in scripts such as <b>RunTest</b>. The 183following options output the value and set the exit code as indicated: 184<pre> 185 ebcdic-nl the code for LF (= NL) in an EBCDIC environment: 186 0x15 or 0x25 187 0 if used in an ASCII environment 188 exit code is always 0 189 linksize the configured internal link size (2, 3, or 4) 190 exit code is set to the link size 191 newline the default newline setting: 192 CR, LF, CRLF, ANYCRLF, ANY, or NUL 193 exit code is always 0 194 bsr the default setting for what \R matches: 195 ANYCRLF or ANY 196 exit code is always 0 197</pre> 198The following options output 1 for true or 0 for false, and set the exit code 199to the same value: 200<pre> 201 backslash-C \C is supported (not locked out) 202 ebcdic compiled for an EBCDIC environment 203 jit just-in-time support is available 204 pcre2-16 the 16-bit library was built 205 pcre2-32 the 32-bit library was built 206 pcre2-8 the 8-bit library was built 207 unicode Unicode support is available 208</pre> 209If an unknown option is given, an error message is output; the exit code is 0. 210</P> 211<P> 212<b>-d</b> 213Behave as if each pattern has the <b>debug</b> modifier; the internal 214form and information about the compiled pattern is output after compilation; 215<b>-d</b> is equivalent to <b>-b -i</b>. 216</P> 217<P> 218<b>-dfa</b> 219Behave as if each subject line has the <b>dfa</b> modifier; matching is done 220using the <b>pcre2_dfa_match()</b> function instead of the default 221<b>pcre2_match()</b>. 222</P> 223<P> 224<b>-error</b> <i>number[,number,...]</i> 225Call <b>pcre2_get_error_message()</b> for each of the error numbers in the 226comma-separated list, display the resulting messages on the standard output, 227then exit with zero exit code. The numbers may be positive or negative. This is 228a convenience facility for PCRE2 maintainers. 229</P> 230<P> 231<b>-help</b> 232Output a brief summary these options and then exit. 233</P> 234<P> 235<b>-i</b> 236Behave as if each pattern has the <b>info</b> modifier; information about the 237compiled pattern is given after compilation. 238</P> 239<P> 240<b>-jit</b> 241Behave as if each pattern line has the <b>jit</b> modifier; after successful 242compilation, each pattern is passed to the just-in-time compiler, if available. 243</P> 244<P> 245<b>-jitverify</b> 246Behave as if each pattern line has the <b>jitverify</b> modifier; after 247successful compilation, each pattern is passed to the just-in-time compiler, if 248available, and the use of JIT is verified. 249</P> 250<P> 251<b>-LM</b> 252List modifiers: write a list of available pattern and subject modifiers to the 253standard output, then exit with zero exit code. All other options are ignored. 254If both -C and -LM are present, whichever is first is recognized. 255</P> 256<P> 257\fB-pattern\fB <i>modifier-list</i> 258Behave as if each pattern line contains the given modifiers. 259</P> 260<P> 261<b>-q</b> 262Do not output the version number of <b>pcre2test</b> at the start of execution. 263</P> 264<P> 265<b>-S</b> <i>size</i> 266On Unix-like systems, set the size of the run-time stack to <i>size</i> 267mebibytes (units of 1024*1024 bytes). 268</P> 269<P> 270<b>-subject</b> <i>modifier-list</i> 271Behave as if each subject line contains the given modifiers. 272</P> 273<P> 274<b>-t</b> 275Run each compile and match many times with a timer, and output the resulting 276times per compile or match. When JIT is used, separate times are given for the 277initial compile and the JIT compile. You can control the number of iterations 278that are used for timing by following <b>-t</b> with a number (as a separate 279item on the command line). For example, "-t 1000" iterates 1000 times. The 280default is to iterate 500,000 times. 281</P> 282<P> 283<b>-tm</b> 284This is like <b>-t</b> except that it times only the matching phase, not the 285compile phase. 286</P> 287<P> 288<b>-T</b> <b>-TM</b> 289These behave like <b>-t</b> and <b>-tm</b>, but in addition, at the end of a run, 290the total times for all compiles and matches are output. 291</P> 292<P> 293<b>-version</b> 294Output the PCRE2 version number and then exit. 295</P> 296<br><a name="SEC5" href="#TOC1">DESCRIPTION</a><br> 297<P> 298If <b>pcre2test</b> is given two filename arguments, it reads from the first and 299writes to the second. If the first name is "-", input is taken from the 300standard input. If <b>pcre2test</b> is given only one argument, it reads from 301that file and writes to stdout. Otherwise, it reads from stdin and writes to 302stdout. 303</P> 304<P> 305When <b>pcre2test</b> is built, a configuration option can specify that it 306should be linked with the <b>libreadline</b> or <b>libedit</b> library. When this 307is done, if the input is from a terminal, it is read using the <b>readline()</b> 308function. This provides line-editing and history facilities. The output from 309the <b>-help</b> option states whether or not <b>readline()</b> will be used. 310</P> 311<P> 312The program handles any number of tests, each of which consists of a set of 313input lines. Each set starts with a regular expression pattern, followed by any 314number of subject lines to be matched against that pattern. In between sets of 315test data, command lines that begin with # may appear. This file format, with 316some restrictions, can also be processed by the <b>perltest.sh</b> script that 317is distributed with PCRE2 as a means of checking that the behaviour of PCRE2 318and Perl is the same. For a specification of <b>perltest.sh</b>, see the 319comments near its beginning. 320</P> 321<P> 322When the input is a terminal, <b>pcre2test</b> prompts for each line of input, 323using "re>" to prompt for regular expression patterns, and "data>" to prompt 324for subject lines. Command lines starting with # can be entered only in 325response to the "re>" prompt. 326</P> 327<P> 328Each subject line is matched separately and independently. If you want to do 329multi-line matches, you have to use the \n escape sequence (or \r or \r\n, 330etc., depending on the newline setting) in a single line of input to encode the 331newline sequences. There is no limit on the length of subject lines; the input 332buffer is automatically extended if it is too small. There are replication 333features that makes it possible to generate long repetitive pattern or subject 334lines without having to supply them explicitly. 335</P> 336<P> 337An empty line or the end of the file signals the end of the subject lines for a 338test, at which point a new pattern or command line is expected if there is 339still input to be read. 340</P> 341<br><a name="SEC6" href="#TOC1">COMMAND LINES</a><br> 342<P> 343In between sets of test data, a line that begins with # is interpreted as a 344command line. If the first character is followed by white space or an 345exclamation mark, the line is treated as a comment, and ignored. Otherwise, the 346following commands are recognized: 347<pre> 348 #forbid_utf 349</pre> 350Subsequent patterns automatically have the PCRE2_NEVER_UTF and PCRE2_NEVER_UCP 351options set, which locks out the use of the PCRE2_UTF and PCRE2_UCP options and 352the use of (*UTF) and (*UCP) at the start of patterns. This command also forces 353an error if a subsequent pattern contains any occurrences of \P, \p, or \X, 354which are still supported when PCRE2_UTF is not set, but which require Unicode 355property support to be included in the library. 356</P> 357<P> 358This is a trigger guard that is used in test files to ensure that UTF or 359Unicode property tests are not accidentally added to files that are used when 360Unicode support is not included in the library. Setting PCRE2_NEVER_UTF and 361PCRE2_NEVER_UCP as a default can also be obtained by the use of <b>#pattern</b>; 362the difference is that <b>#forbid_utf</b> cannot be unset, and the automatic 363options are not displayed in pattern information, to avoid cluttering up test 364output. 365<pre> 366 #load <filename> 367</pre> 368This command is used to load a set of precompiled patterns from a file, as 369described in the section entitled "Saving and restoring compiled patterns" 370<a href="#saverestore">below.</a> 371<pre> 372 #newline_default [<newline-list>] 373</pre> 374When PCRE2 is built, a default newline convention can be specified. This 375determines which characters and/or character pairs are recognized as indicating 376a newline in a pattern or subject string. The default can be overridden when a 377pattern is compiled. The standard test files contain tests of various newline 378conventions, but the majority of the tests expect a single linefeed to be 379recognized as a newline by default. Without special action the tests would fail 380when PCRE2 is compiled with either CR or CRLF as the default newline. 381</P> 382<P> 383The #newline_default command specifies a list of newline types that are 384acceptable as the default. The types must be one of CR, LF, CRLF, ANYCRLF, 385ANY, or NUL (in upper or lower case), for example: 386<pre> 387 #newline_default LF Any anyCRLF 388</pre> 389If the default newline is in the list, this command has no effect. Otherwise, 390except when testing the POSIX API, a <b>newline</b> modifier that specifies the 391first newline convention in the list (LF in the above example) is added to any 392pattern that does not already have a <b>newline</b> modifier. If the newline 393list is empty, the feature is turned off. This command is present in a number 394of the standard test input files. 395</P> 396<P> 397When the POSIX API is being tested there is no way to override the default 398newline convention, though it is possible to set the newline convention from 399within the pattern. A warning is given if the <b>posix</b> or <b>posix_nosub</b> 400modifier is used when <b>#newline_default</b> would set a default for the 401non-POSIX API. 402<pre> 403 #pattern <modifier-list> 404</pre> 405This command sets a default modifier list that applies to all subsequent 406patterns. Modifiers on a pattern can change these settings. 407<pre> 408 #perltest 409</pre> 410The appearance of this line causes all subsequent modifier settings to be 411checked for compatibility with the <b>perltest.sh</b> script, which is used to 412confirm that Perl gives the same results as PCRE2. Also, apart from comment 413lines, #pattern commands, and #subject commands that set or unset "mark", no 414command lines are permitted, because they and many of the modifiers are 415specific to <b>pcre2test</b>, and should not be used in test files that are also 416processed by <b>perltest.sh</b>. The <b>#perltest</b> command helps detect tests 417that are accidentally put in the wrong file. 418<pre> 419 #pop [<modifiers>] 420 #popcopy [<modifiers>] 421</pre> 422These commands are used to manipulate the stack of compiled patterns, as 423described in the section entitled "Saving and restoring compiled patterns" 424<a href="#saverestore">below.</a> 425<pre> 426 #save <filename> 427</pre> 428This command is used to save a set of compiled patterns to a file, as described 429in the section entitled "Saving and restoring compiled patterns" 430<a href="#saverestore">below.</a> 431<pre> 432 #subject <modifier-list> 433</pre> 434This command sets a default modifier list that applies to all subsequent 435subject lines. Modifiers on a subject line can change these settings. 436</P> 437<br><a name="SEC7" href="#TOC1">MODIFIER SYNTAX</a><br> 438<P> 439Modifier lists are used with both pattern and subject lines. Items in a list 440are separated by commas followed by optional white space. Trailing whitespace 441in a modifier list is ignored. Some modifiers may be given for both patterns 442and subject lines, whereas others are valid only for one or the other. Each 443modifier has a long name, for example "anchored", and some of them must be 444followed by an equals sign and a value, for example, "offset=12". Values cannot 445contain comma characters, but may contain spaces. Modifiers that do not take 446values may be preceded by a minus sign to turn off a previous setting. 447</P> 448<P> 449A few of the more common modifiers can also be specified as single letters, for 450example "i" for "caseless". In documentation, following the Perl convention, 451these are written with a slash ("the /i modifier") for clarity. Abbreviated 452modifiers must all be concatenated in the first item of a modifier list. If the 453first item is not recognized as a long modifier name, it is interpreted as a 454sequence of these abbreviations. For example: 455<pre> 456 /abc/ig,newline=cr,jit=3 457</pre> 458This is a pattern line whose modifier list starts with two one-letter modifiers 459(/i and /g). The lower-case abbreviated modifiers are the same as used in Perl. 460</P> 461<br><a name="SEC8" href="#TOC1">PATTERN SYNTAX</a><br> 462<P> 463A pattern line must start with one of the following characters (common symbols, 464excluding pattern meta-characters): 465<pre> 466 / ! " ' ` - = _ : ; , % & @ ~ 467</pre> 468This is interpreted as the pattern's delimiter. A regular expression may be 469continued over several input lines, in which case the newline characters are 470included within it. It is possible to include the delimiter within the pattern 471by escaping it with a backslash, for example 472<pre> 473 /abc\/def/ 474</pre> 475If you do this, the escape and the delimiter form part of the pattern, but 476since the delimiters are all non-alphanumeric, this does not affect its 477interpretation. If the terminating delimiter is immediately followed by a 478backslash, for example, 479<pre> 480 /abc/\ 481</pre> 482then a backslash is added to the end of the pattern. This is done to provide a 483way of testing the error condition that arises if a pattern finishes with a 484backslash, because 485<pre> 486 /abc\/ 487</pre> 488is interpreted as the first line of a pattern that starts with "abc/", causing 489pcre2test to read the next line as a continuation of the regular expression. 490</P> 491<P> 492A pattern can be followed by a modifier list (details below). 493</P> 494<br><a name="SEC9" href="#TOC1">SUBJECT LINE SYNTAX</a><br> 495<P> 496Before each subject line is passed to <b>pcre2_match()</b> or 497<b>pcre2_dfa_match()</b>, leading and trailing white space is removed, and the 498line is scanned for backslash escapes, unless the <b>subject_literal</b> 499modifier was set for the pattern. The following provide a means of encoding 500non-printing characters in a visible way: 501<pre> 502 \a alarm (BEL, \x07) 503 \b backspace (\x08) 504 \e escape (\x27) 505 \f form feed (\x0c) 506 \n newline (\x0a) 507 \r carriage return (\x0d) 508 \t tab (\x09) 509 \v vertical tab (\x0b) 510 \nnn octal character (up to 3 octal digits); always 511 a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode 512 \o{dd...} octal character (any number of octal digits} 513 \xhh hexadecimal byte (up to 2 hex digits) 514 \x{hh...} hexadecimal character (any number of hex digits) 515</pre> 516The use of \x{hh...} is not dependent on the use of the <b>utf</b> modifier on 517the pattern. It is recognized always. There may be any number of hexadecimal 518digits inside the braces; invalid values provoke error messages. 519</P> 520<P> 521Note that \xhh specifies one byte rather than one character in UTF-8 mode; 522this makes it possible to construct invalid UTF-8 sequences for testing 523purposes. On the other hand, \x{hh} is interpreted as a UTF-8 character in 524UTF-8 mode, generating more than one byte if the value is greater than 127. 525When testing the 8-bit library not in UTF-8 mode, \x{hh} generates one byte 526for values less than 256, and causes an error for greater values. 527</P> 528<P> 529In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it 530possible to construct invalid UTF-16 sequences for testing purposes. 531</P> 532<P> 533In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This makes it 534possible to construct invalid UTF-32 sequences for testing purposes. 535</P> 536<P> 537There is a special backslash sequence that specifies replication of one or more 538characters: 539<pre> 540 \[<characters>]{<count>} 541</pre> 542This makes it possible to test long strings without having to provide them as 543part of the file. For example: 544<pre> 545 \[abc]{4} 546</pre> 547is converted to "abcabcabcabc". This feature does not support nesting. To 548include a closing square bracket in the characters, code it as \x5D. 549</P> 550<P> 551A backslash followed by an equals sign marks the end of the subject string and 552the start of a modifier list. For example: 553<pre> 554 abc\=notbol,notempty 555</pre> 556If the subject string is empty and \= is followed by whitespace, the line is 557treated as a comment line, and is not used for matching. For example: 558<pre> 559 \= This is a comment. 560 abc\= This is an invalid modifier list. 561</pre> 562A backslash followed by any other non-alphanumeric character just escapes that 563character. A backslash followed by anything else causes an error. However, if 564the very last character in the line is a backslash (and there is no modifier 565list), it is ignored. This gives a way of passing an empty line as data, since 566a real empty line terminates the data input. 567</P> 568<P> 569If the <b>subject_literal</b> modifier is set for a pattern, all subject lines 570that follow are treated as literals, with no special treatment of backslashes. 571No replication is possible, and any subject modifiers must be set as defaults 572by a <b>#subject</b> command. 573</P> 574<br><a name="SEC10" href="#TOC1">PATTERN MODIFIERS</a><br> 575<P> 576There are several types of modifier that can appear in pattern lines. Except 577where noted below, they may also be used in <b>#pattern</b> commands. A 578pattern's modifier list can add to or override default modifiers that were set 579by a previous <b>#pattern</b> command. 580<a name="optionmodifiers"></a></P> 581<br><b> 582Setting compilation options 583</b><br> 584<P> 585The following modifiers set options for <b>pcre2_compile()</b>. Most of them set 586bits in the options argument of that function, but those whose names start with 587PCRE2_EXTRA are additional options that are set in the compile context. For the 588main options, there are some single-letter abbreviations that are the same as 589Perl options. There is special handling for /x: if a second x is present, 590PCRE2_EXTENDED is converted into PCRE2_EXTENDED_MORE as in Perl. A third 591appearance adds PCRE2_EXTENDED as well, though this makes no difference to the 592way <b>pcre2_compile()</b> behaves. See 593<a href="pcre2api.html"><b>pcre2api</b></a> 594for a description of the effects of these options. 595<pre> 596 allow_empty_class set PCRE2_ALLOW_EMPTY_CLASS 597 allow_surrogate_escapes set PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES 598 alt_bsux set PCRE2_ALT_BSUX 599 alt_circumflex set PCRE2_ALT_CIRCUMFLEX 600 alt_verbnames set PCRE2_ALT_VERBNAMES 601 anchored set PCRE2_ANCHORED 602 auto_callout set PCRE2_AUTO_CALLOUT 603 bad_escape_is_literal set PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL 604 /i caseless set PCRE2_CASELESS 605 dollar_endonly set PCRE2_DOLLAR_ENDONLY 606 /s dotall set PCRE2_DOTALL 607 dupnames set PCRE2_DUPNAMES 608 endanchored set PCRE2_ENDANCHORED 609 escaped_cr_is_lf set PCRE2_EXTRA_ESCAPED_CR_IS_LF 610 /x extended set PCRE2_EXTENDED 611 /xx extended_more set PCRE2_EXTENDED_MORE 612 extra_alt_bsux set PCRE2_EXTRA_ALT_BSUX 613 firstline set PCRE2_FIRSTLINE 614 literal set PCRE2_LITERAL 615 match_line set PCRE2_EXTRA_MATCH_LINE 616 match_unset_backref set PCRE2_MATCH_UNSET_BACKREF 617 match_word set PCRE2_EXTRA_MATCH_WORD 618 /m multiline set PCRE2_MULTILINE 619 never_backslash_c set PCRE2_NEVER_BACKSLASH_C 620 never_ucp set PCRE2_NEVER_UCP 621 never_utf set PCRE2_NEVER_UTF 622 /n no_auto_capture set PCRE2_NO_AUTO_CAPTURE 623 no_auto_possess set PCRE2_NO_AUTO_POSSESS 624 no_dotstar_anchor set PCRE2_NO_DOTSTAR_ANCHOR 625 no_start_optimize set PCRE2_NO_START_OPTIMIZE 626 no_utf_check set PCRE2_NO_UTF_CHECK 627 ucp set PCRE2_UCP 628 ungreedy set PCRE2_UNGREEDY 629 use_offset_limit set PCRE2_USE_OFFSET_LIMIT 630 utf set PCRE2_UTF 631</pre> 632As well as turning on the PCRE2_UTF option, the <b>utf</b> modifier causes all 633non-printing characters in output strings to be printed using the \x{hh...} 634notation. Otherwise, those less than 0x100 are output in hex without the curly 635brackets. Setting <b>utf</b> in 16-bit or 32-bit mode also causes pattern and 636subject strings to be translated to UTF-16 or UTF-32, respectively, before 637being passed to library functions. 638<a name="controlmodifiers"></a></P> 639<br><b> 640Setting compilation controls 641</b><br> 642<P> 643The following modifiers affect the compilation process or request information 644about the pattern. There are single-letter abbreviations for some that are 645heavily used in the test files. 646<pre> 647 bsr=[anycrlf|unicode] specify \R handling 648 /B bincode show binary code without lengths 649 callout_info show callout information 650 convert=<options> request foreign pattern conversion 651 convert_glob_escape=c set glob escape character 652 convert_glob_separator=c set glob separator character 653 convert_length set convert buffer length 654 debug same as info,fullbincode 655 framesize show matching frame size 656 fullbincode show binary code with lengths 657 /I info show info about compiled pattern 658 hex unquoted characters are hexadecimal 659 jit[=<number>] use JIT 660 jitfast use JIT fast path 661 jitverify verify JIT use 662 locale=<name> use this locale 663 max_pattern_length=<n> set the maximum pattern length 664 memory show memory used 665 newline=<type> set newline type 666 null_context compile with a NULL context 667 parens_nest_limit=<n> set maximum parentheses depth 668 posix use the POSIX API 669 posix_nosub use the POSIX API with REG_NOSUB 670 push push compiled pattern onto the stack 671 pushcopy push a copy onto the stack 672 stackguard=<number> test the stackguard feature 673 subject_literal treat all subject lines as literal 674 tables=[0|1|2] select internal tables 675 use_length do not zero-terminate the pattern 676 utf8_input treat input as UTF-8 677</pre> 678The effects of these modifiers are described in the following sections. 679</P> 680<br><b> 681Newline and \R handling 682</b><br> 683<P> 684The <b>bsr</b> modifier specifies what \R in a pattern should match. If it is 685set to "anycrlf", \R matches CR, LF, or CRLF only. If it is set to "unicode", 686\R matches any Unicode newline sequence. The default can be specified when 687PCRE2 is built; if it is not, the default is set to Unicode. 688</P> 689<P> 690The <b>newline</b> modifier specifies which characters are to be interpreted as 691newlines, both in the pattern and in subject lines. The type must be one of CR, 692LF, CRLF, ANYCRLF, ANY, or NUL (in upper or lower case). 693</P> 694<br><b> 695Information about a pattern 696</b><br> 697<P> 698The <b>debug</b> modifier is a shorthand for <b>info,fullbincode</b>, requesting 699all available information. 700</P> 701<P> 702The <b>bincode</b> modifier causes a representation of the compiled code to be 703output after compilation. This information does not contain length and offset 704values, which ensures that the same output is generated for different internal 705link sizes and different code unit widths. By using <b>bincode</b>, the same 706regression tests can be used in different environments. 707</P> 708<P> 709The <b>fullbincode</b> modifier, by contrast, <i>does</i> include length and 710offset values. This is used in a few special tests that run only for specific 711code unit widths and link sizes, and is also useful for one-off tests. 712</P> 713<P> 714The <b>info</b> modifier requests information about the compiled pattern 715(whether it is anchored, has a fixed first character, and so on). The 716information is obtained from the <b>pcre2_pattern_info()</b> function. Here are 717some typical examples: 718<pre> 719 re> /(?i)(^a|^b)/m,info 720 Capture group count = 1 721 Compile options: multiline 722 Overall options: caseless multiline 723 First code unit at start or follows newline 724 Subject length lower bound = 1 725 726 re> /(?i)abc/info 727 Capture group count = 0 728 Compile options: <none> 729 Overall options: caseless 730 First code unit = 'a' (caseless) 731 Last code unit = 'c' (caseless) 732 Subject length lower bound = 3 733</pre> 734"Compile options" are those specified by modifiers; "overall options" have 735added options that are taken or deduced from the pattern. If both sets of 736options are the same, just a single "options" line is output; if there are no 737options, the line is omitted. "First code unit" is where any match must start; 738if there is more than one they are listed as "starting code units". "Last code 739unit" is the last literal code unit that must be present in any match. This is 740not necessarily the last character. These lines are omitted if no starting or 741ending code units are recorded. 742</P> 743<P> 744The <b>framesize</b> modifier shows the size, in bytes, of the storage frames 745used by <b>pcre2_match()</b> for handling backtracking. The size depends on the 746number of capturing parentheses in the pattern. 747</P> 748<P> 749The <b>callout_info</b> modifier requests information about all the callouts in 750the pattern. A list of them is output at the end of any other information that 751is requested. For each callout, either its number or string is given, followed 752by the item that follows it in the pattern. 753</P> 754<br><b> 755Passing a NULL context 756</b><br> 757<P> 758Normally, <b>pcre2test</b> passes a context block to <b>pcre2_compile()</b>. If 759the <b>null_context</b> modifier is set, however, NULL is passed. This is for 760testing that <b>pcre2_compile()</b> behaves correctly in this case (it uses 761default values). 762</P> 763<br><b> 764Specifying pattern characters in hexadecimal 765</b><br> 766<P> 767The <b>hex</b> modifier specifies that the characters of the pattern, except for 768substrings enclosed in single or double quotes, are to be interpreted as pairs 769of hexadecimal digits. This feature is provided as a way of creating patterns 770that contain binary zeros and other non-printing characters. White space is 771permitted between pairs of digits. For example, this pattern contains three 772characters: 773<pre> 774 /ab 32 59/hex 775</pre> 776Parts of such a pattern are taken literally if quoted. This pattern contains 777nine characters, only two of which are specified in hexadecimal: 778<pre> 779 /ab "literal" 32/hex 780</pre> 781Either single or double quotes may be used. There is no way of including 782the delimiter within a substring. The <b>hex</b> and <b>expand</b> modifiers are 783mutually exclusive. 784</P> 785<br><b> 786Specifying the pattern's length 787</b><br> 788<P> 789By default, patterns are passed to the compiling functions as zero-terminated 790strings but can be passed by length instead of being zero-terminated. The 791<b>use_length</b> modifier causes this to happen. Using a length happens 792automatically (whether or not <b>use_length</b> is set) when <b>hex</b> is set, 793because patterns specified in hexadecimal may contain binary zeros. 794</P> 795<P> 796If <b>hex</b> or <b>use_length</b> is used with the POSIX wrapper API (see 797<a href="#posixwrapper">"Using the POSIX wrapper API"</a> 798below), the REG_PEND extension is used to pass the pattern's length. 799</P> 800<br><b> 801Specifying wide characters in 16-bit and 32-bit modes 802</b><br> 803<P> 804In 16-bit and 32-bit modes, all input is automatically treated as UTF-8 and 805translated to UTF-16 or UTF-32 when the <b>utf</b> modifier is set. For testing 806the 16-bit and 32-bit libraries in non-UTF mode, the <b>utf8_input</b> modifier 807can be used. It is mutually exclusive with <b>utf</b>. Input lines are 808interpreted as UTF-8 as a means of specifying wide characters. More details are 809given in 810<a href="#inputencoding">"Input encoding"</a> 811above. 812</P> 813<br><b> 814Generating long repetitive patterns 815</b><br> 816<P> 817Some tests use long patterns that are very repetitive. Instead of creating a 818very long input line for such a pattern, you can use a special repetition 819feature, similar to the one described for subject lines above. If the 820<b>expand</b> modifier is present on a pattern, parts of the pattern that have 821the form 822<pre> 823 \[<characters>]{<count>} 824</pre> 825are expanded before the pattern is passed to <b>pcre2_compile()</b>. For 826example, \[AB]{6000} is expanded to "ABAB..." 6000 times. This construction 827cannot be nested. An initial "\[" sequence is recognized only if "]{" followed 828by decimal digits and "}" is found later in the pattern. If not, the characters 829remain in the pattern unaltered. The <b>expand</b> and <b>hex</b> modifiers are 830mutually exclusive. 831</P> 832<P> 833If part of an expanded pattern looks like an expansion, but is really part of 834the actual pattern, unwanted expansion can be avoided by giving two values in 835the quantifier. For example, \[AB]{6000,6000} is not recognized as an 836expansion item. 837</P> 838<P> 839If the <b>info</b> modifier is set on an expanded pattern, the result of the 840expansion is included in the information that is output. 841</P> 842<br><b> 843JIT compilation 844</b><br> 845<P> 846Just-in-time (JIT) compiling is a heavyweight optimization that can greatly 847speed up pattern matching. See the 848<a href="pcre2jit.html"><b>pcre2jit</b></a> 849documentation for details. JIT compiling happens, optionally, after a pattern 850has been successfully compiled into an internal form. The JIT compiler converts 851this to optimized machine code. It needs to know whether the match-time options 852PCRE2_PARTIAL_HARD and PCRE2_PARTIAL_SOFT are going to be used, because 853different code is generated for the different cases. See the <b>partial</b> 854modifier in "Subject Modifiers" 855<a href="#subjectmodifiers">below</a> 856for details of how these options are specified for each match attempt. 857</P> 858<P> 859JIT compilation is requested by the <b>jit</b> pattern modifier, which may 860optionally be followed by an equals sign and a number in the range 0 to 7. 861The three bits that make up the number specify which of the three JIT operating 862modes are to be compiled: 863<pre> 864 1 compile JIT code for non-partial matching 865 2 compile JIT code for soft partial matching 866 4 compile JIT code for hard partial matching 867</pre> 868The possible values for the <b>jit</b> modifier are therefore: 869<pre> 870 0 disable JIT 871 1 normal matching only 872 2 soft partial matching only 873 3 normal and soft partial matching 874 4 hard partial matching only 875 6 soft and hard partial matching only 876 7 all three modes 877</pre> 878If no number is given, 7 is assumed. The phrase "partial matching" means a call 879to <b>pcre2_match()</b> with either the PCRE2_PARTIAL_SOFT or the 880PCRE2_PARTIAL_HARD option set. Note that such a call may return a complete 881match; the options enable the possibility of a partial match, but do not 882require it. Note also that if you request JIT compilation only for partial 883matching (for example, jit=2) but do not set the <b>partial</b> modifier on a 884subject line, that match will not use JIT code because none was compiled for 885non-partial matching. 886</P> 887<P> 888If JIT compilation is successful, the compiled JIT code will automatically be 889used when an appropriate type of match is run, except when incompatible 890run-time options are specified. For more details, see the 891<a href="pcre2jit.html"><b>pcre2jit</b></a> 892documentation. See also the <b>jitstack</b> modifier below for a way of 893setting the size of the JIT stack. 894</P> 895<P> 896If the <b>jitfast</b> modifier is specified, matching is done using the JIT 897"fast path" interface, <b>pcre2_jit_match()</b>, which skips some of the sanity 898checks that are done by <b>pcre2_match()</b>, and of course does not work when 899JIT is not supported. If <b>jitfast</b> is specified without <b>jit</b>, jit=7 is 900assumed. 901</P> 902<P> 903If the <b>jitverify</b> modifier is specified, information about the compiled 904pattern shows whether JIT compilation was or was not successful. If 905<b>jitverify</b> is specified without <b>jit</b>, jit=7 is assumed. If JIT 906compilation is successful when <b>jitverify</b> is set, the text "(JIT)" is 907added to the first output line after a match or non match when JIT-compiled 908code was actually used in the match. 909</P> 910<br><b> 911Setting a locale 912</b><br> 913<P> 914The <b>locale</b> modifier must specify the name of a locale, for example: 915<pre> 916 /pattern/locale=fr_FR 917</pre> 918The given locale is set, <b>pcre2_maketables()</b> is called to build a set of 919character tables for the locale, and this is then passed to 920<b>pcre2_compile()</b> when compiling the regular expression. The same tables 921are used when matching the following subject lines. The <b>locale</b> modifier 922applies only to the pattern on which it appears, but can be given in a 923<b>#pattern</b> command if a default is needed. Setting a locale and alternate 924character tables are mutually exclusive. 925</P> 926<br><b> 927Showing pattern memory 928</b><br> 929<P> 930The <b>memory</b> modifier causes the size in bytes of the memory used to hold 931the compiled pattern to be output. This does not include the size of the 932<b>pcre2_code</b> block; it is just the actual compiled data. If the pattern is 933subsequently passed to the JIT compiler, the size of the JIT compiled code is 934also output. Here is an example: 935<pre> 936 re> /a(b)c/jit,memory 937 Memory allocation (code space): 21 938 Memory allocation (JIT code): 1910 939 940</PRE> 941</P> 942<br><b> 943Limiting nested parentheses 944</b><br> 945<P> 946The <b>parens_nest_limit</b> modifier sets a limit on the depth of nested 947parentheses in a pattern. Breaching the limit causes a compilation error. 948The default for the library is set when PCRE2 is built, but <b>pcre2test</b> 949sets its own default of 220, which is required for running the standard test 950suite. 951</P> 952<br><b> 953Limiting the pattern length 954</b><br> 955<P> 956The <b>max_pattern_length</b> modifier sets a limit, in code units, to the 957length of pattern that <b>pcre2_compile()</b> will accept. Breaching the limit 958causes a compilation error. The default is the largest number a PCRE2_SIZE 959variable can hold (essentially unlimited). 960<a name="posixwrapper"></a></P> 961<br><b> 962Using the POSIX wrapper API 963</b><br> 964<P> 965The <b>posix</b> and <b>posix_nosub</b> modifiers cause <b>pcre2test</b> to call 966PCRE2 via the POSIX wrapper API rather than its native API. When 967<b>posix_nosub</b> is used, the POSIX option REG_NOSUB is passed to 968<b>regcomp()</b>. The POSIX wrapper supports only the 8-bit library. Note that 969it does not imply POSIX matching semantics; for more detail see the 970<a href="pcre2posix.html"><b>pcre2posix</b></a> 971documentation. The following pattern modifiers set options for the 972<b>regcomp()</b> function: 973<pre> 974 caseless REG_ICASE 975 multiline REG_NEWLINE 976 dotall REG_DOTALL ) 977 ungreedy REG_UNGREEDY ) These options are not part of 978 ucp REG_UCP ) the POSIX standard 979 utf REG_UTF8 ) 980</pre> 981The <b>regerror_buffsize</b> modifier specifies a size for the error buffer that 982is passed to <b>regerror()</b> in the event of a compilation error. For example: 983<pre> 984 /abc/posix,regerror_buffsize=20 985</pre> 986This provides a means of testing the behaviour of <b>regerror()</b> when the 987buffer is too small for the error message. If this modifier has not been set, a 988large buffer is used. 989</P> 990<P> 991The <b>aftertext</b> and <b>allaftertext</b> subject modifiers work as described 992below. All other modifiers are either ignored, with a warning message, or cause 993an error. 994</P> 995<P> 996The pattern is passed to <b>regcomp()</b> as a zero-terminated string by 997default, but if the <b>use_length</b> or <b>hex</b> modifiers are set, the 998REG_PEND extension is used to pass it by length. 999</P> 1000<br><b> 1001Testing the stack guard feature 1002</b><br> 1003<P> 1004The <b>stackguard</b> modifier is used to test the use of 1005<b>pcre2_set_compile_recursion_guard()</b>, a function that is provided to 1006enable stack availability to be checked during compilation (see the 1007<a href="pcre2api.html"><b>pcre2api</b></a> 1008documentation for details). If the number specified by the modifier is greater 1009than zero, <b>pcre2_set_compile_recursion_guard()</b> is called to set up 1010callback from <b>pcre2_compile()</b> to a local function. The argument it 1011receives is the current nesting parenthesis depth; if this is greater than the 1012value given by the modifier, non-zero is returned, causing the compilation to 1013be aborted. 1014</P> 1015<br><b> 1016Using alternative character tables 1017</b><br> 1018<P> 1019The value specified for the <b>tables</b> modifier must be one of the digits 0, 10201, or 2. It causes a specific set of built-in character tables to be passed to 1021<b>pcre2_compile()</b>. This is used in the PCRE2 tests to check behaviour with 1022different character tables. The digit specifies the tables as follows: 1023<pre> 1024 0 do not pass any special character tables 1025 1 the default ASCII tables, as distributed in 1026 pcre2_chartables.c.dist 1027 2 a set of tables defining ISO 8859 characters 1028</pre> 1029In table 2, some characters whose codes are greater than 128 are identified as 1030letters, digits, spaces, etc. Setting alternate character tables and a locale 1031are mutually exclusive. 1032</P> 1033<br><b> 1034Setting certain match controls 1035</b><br> 1036<P> 1037The following modifiers are really subject modifiers, and are described under 1038"Subject Modifiers" below. However, they may be included in a pattern's 1039modifier list, in which case they are applied to every subject line that is 1040processed with that pattern. These modifiers do not affect the compilation 1041process. 1042<pre> 1043 aftertext show text after match 1044 allaftertext show text after captures 1045 allcaptures show all captures 1046 allvector show the entire ovector 1047 allusedtext show all consulted text 1048 altglobal alternative global matching 1049 /g global global matching 1050 jitstack=<n> set size of JIT stack 1051 mark show mark values 1052 replace=<string> specify a replacement string 1053 startchar show starting character when relevant 1054 substitute_callout use substitution callouts 1055 substitute_extended use PCRE2_SUBSTITUTE_EXTENDED 1056 substitute_skip=<n> skip substitution number n 1057 substitute_overflow_length use PCRE2_SUBSTITUTE_OVERFLOW_LENGTH 1058 substitute_stop=<n> skip substitution number n and greater 1059 substitute_unknown_unset use PCRE2_SUBSTITUTE_UNKNOWN_UNSET 1060 substitute_unset_empty use PCRE2_SUBSTITUTE_UNSET_EMPTY 1061</pre> 1062These modifiers may not appear in a <b>#pattern</b> command. If you want them as 1063defaults, set them in a <b>#subject</b> command. 1064</P> 1065<br><b> 1066Specifying literal subject lines 1067</b><br> 1068<P> 1069If the <b>subject_literal</b> modifier is present on a pattern, all the subject 1070lines that it matches are taken as literal strings, with no interpretation of 1071backslashes. It is not possible to set subject modifiers on such lines, but any 1072that are set as defaults by a <b>#subject</b> command are recognized. 1073</P> 1074<br><b> 1075Saving a compiled pattern 1076</b><br> 1077<P> 1078When a pattern with the <b>push</b> modifier is successfully compiled, it is 1079pushed onto a stack of compiled patterns, and <b>pcre2test</b> expects the next 1080line to contain a new pattern (or a command) instead of a subject line. This 1081facility is used when saving compiled patterns to a file, as described in the 1082section entitled "Saving and restoring compiled patterns" 1083<a href="#saverestore">below.</a> 1084If <b>pushcopy</b> is used instead of <b>push</b>, a copy of the compiled 1085pattern is stacked, leaving the original as current, ready to match the 1086following input lines. This provides a way of testing the 1087<b>pcre2_code_copy()</b> function. 1088The <b>push</b> and <b>pushcopy </b> modifiers are incompatible with compilation 1089modifiers such as <b>global</b> that act at match time. Any that are specified 1090are ignored (for the stacked copy), with a warning message, except for 1091<b>replace</b>, which causes an error. Note that <b>jitverify</b>, which is 1092allowed, does not carry through to any subsequent matching that uses a stacked 1093pattern. 1094</P> 1095<br><b> 1096Testing foreign pattern conversion 1097</b><br> 1098<P> 1099The experimental foreign pattern conversion functions in PCRE2 can be tested by 1100setting the <b>convert</b> modifier. Its argument is a colon-separated list of 1101options, which set the equivalent option for the <b>pcre2_pattern_convert()</b> 1102function: 1103<pre> 1104 glob PCRE2_CONVERT_GLOB 1105 glob_no_starstar PCRE2_CONVERT_GLOB_NO_STARSTAR 1106 glob_no_wild_separator PCRE2_CONVERT_GLOB_NO_WILD_SEPARATOR 1107 posix_basic PCRE2_CONVERT_POSIX_BASIC 1108 posix_extended PCRE2_CONVERT_POSIX_EXTENDED 1109 unset Unset all options 1110</pre> 1111The "unset" value is useful for turning off a default that has been set by a 1112<b>#pattern</b> command. When one of these options is set, the input pattern is 1113passed to <b>pcre2_pattern_convert()</b>. If the conversion is successful, the 1114result is reflected in the output and then passed to <b>pcre2_compile()</b>. The 1115normal <b>utf</b> and <b>no_utf_check</b> options, if set, cause the 1116PCRE2_CONVERT_UTF and PCRE2_CONVERT_NO_UTF_CHECK options to be passed to 1117<b>pcre2_pattern_convert()</b>. 1118</P> 1119<P> 1120By default, the conversion function is allowed to allocate a buffer for its 1121output. However, if the <b>convert_length</b> modifier is set to a value greater 1122than zero, <b>pcre2test</b> passes a buffer of the given length. This makes it 1123possible to test the length check. 1124</P> 1125<P> 1126The <b>convert_glob_escape</b> and <b>convert_glob_separator</b> modifiers can be 1127used to specify the escape and separator characters for glob processing, 1128overriding the defaults, which are operating-system dependent. 1129<a name="subjectmodifiers"></a></P> 1130<br><a name="SEC11" href="#TOC1">SUBJECT MODIFIERS</a><br> 1131<P> 1132The modifiers that can appear in subject lines and the <b>#subject</b> 1133command are of two types. 1134</P> 1135<br><b> 1136Setting match options 1137</b><br> 1138<P> 1139The following modifiers set options for <b>pcre2_match()</b> or 1140<b>pcre2_dfa_match()</b>. See 1141<a href="pcreapi.html"><b>pcreapi</b></a> 1142for a description of their effects. 1143<pre> 1144 anchored set PCRE2_ANCHORED 1145 endanchored set PCRE2_ENDANCHORED 1146 dfa_restart set PCRE2_DFA_RESTART 1147 dfa_shortest set PCRE2_DFA_SHORTEST 1148 no_jit set PCRE2_NO_JIT 1149 no_utf_check set PCRE2_NO_UTF_CHECK 1150 notbol set PCRE2_NOTBOL 1151 notempty set PCRE2_NOTEMPTY 1152 notempty_atstart set PCRE2_NOTEMPTY_ATSTART 1153 noteol set PCRE2_NOTEOL 1154 partial_hard (or ph) set PCRE2_PARTIAL_HARD 1155 partial_soft (or ps) set PCRE2_PARTIAL_SOFT 1156</pre> 1157The partial matching modifiers are provided with abbreviations because they 1158appear frequently in tests. 1159</P> 1160<P> 1161If the <b>posix</b> or <b>posix_nosub</b> modifier was present on the pattern, 1162causing the POSIX wrapper API to be used, the only option-setting modifiers 1163that have any effect are <b>notbol</b>, <b>notempty</b>, and <b>noteol</b>, 1164causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively, to be passed to 1165<b>regexec()</b>. The other modifiers are ignored, with a warning message. 1166</P> 1167<P> 1168There is one additional modifier that can be used with the POSIX wrapper. It is 1169ignored (with a warning) if used for non-POSIX matching. 1170<pre> 1171 posix_startend=<n>[:<m>] 1172</pre> 1173This causes the subject string to be passed to <b>regexec()</b> using the 1174REG_STARTEND option, which uses offsets to specify which part of the string is 1175searched. If only one number is given, the end offset is passed as the end of 1176the subject string. For more detail of REG_STARTEND, see the 1177<a href="pcre2posix.html"><b>pcre2posix</b></a> 1178documentation. If the subject string contains binary zeros (coded as escapes 1179such as \x{00} because <b>pcre2test</b> does not support actual binary zeros in 1180its input), you must use <b>posix_startend</b> to specify its length. 1181</P> 1182<br><b> 1183Setting match controls 1184</b><br> 1185<P> 1186The following modifiers affect the matching process or request additional 1187information. Some of them may also be specified on a pattern line (see above), 1188in which case they apply to every subject line that is matched against that 1189pattern. 1190<pre> 1191 aftertext show text after match 1192 allaftertext show text after captures 1193 allcaptures show all captures 1194 allvector show the entire ovector 1195 allusedtext show all consulted text (non-JIT only) 1196 altglobal alternative global matching 1197 callout_capture show captures at callout time 1198 callout_data=<n> set a value to pass via callouts 1199 callout_error=<n>[:<m>] control callout error 1200 callout_extra show extra callout information 1201 callout_fail=<n>[:<m>] control callout failure 1202 callout_no_where do not show position of a callout 1203 callout_none do not supply a callout function 1204 copy=<number or name> copy captured substring 1205 depth_limit=<n> set a depth limit 1206 dfa use <b>pcre2_dfa_match()</b> 1207 find_limits find match and depth limits 1208 get=<number or name> extract captured substring 1209 getall extract all captured substrings 1210 /g global global matching 1211 heap_limit=<n> set a limit on heap memory (Kbytes) 1212 jitstack=<n> set size of JIT stack 1213 mark show mark values 1214 match_limit=<n> set a match limit 1215 memory show heap memory usage 1216 null_context match with a NULL context 1217 offset=<n> set starting offset 1218 offset_limit=<n> set offset limit 1219 ovector=<n> set size of output vector 1220 recursion_limit=<n> obsolete synonym for depth_limit 1221 replace=<string> specify a replacement string 1222 startchar show startchar when relevant 1223 startoffset=<n> same as offset=<n> 1224 substitute_callout use substitution callouts 1225 substitute_extedded use PCRE2_SUBSTITUTE_EXTENDED 1226 substitute_skip=<n> skip substitution number n 1227 substitute_overflow_length use PCRE2_SUBSTITUTE_OVERFLOW_LENGTH 1228 substitute_stop=<n> skip substitution number n and greater 1229 substitute_unknown_unset use PCRE2_SUBSTITUTE_UNKNOWN_UNSET 1230 substitute_unset_empty use PCRE2_SUBSTITUTE_UNSET_EMPTY 1231 zero_terminate pass the subject as zero-terminated 1232</pre> 1233The effects of these modifiers are described in the following sections. When 1234matching via the POSIX wrapper API, the <b>aftertext</b>, <b>allaftertext</b>, 1235and <b>ovector</b> subject modifiers work as described below. All other 1236modifiers are either ignored, with a warning message, or cause an error. 1237</P> 1238<br><b> 1239Showing more text 1240</b><br> 1241<P> 1242The <b>aftertext</b> modifier requests that as well as outputting the part of 1243the subject string that matched the entire pattern, <b>pcre2test</b> should in 1244addition output the remainder of the subject string. This is useful for tests 1245where the subject contains multiple copies of the same substring. The 1246<b>allaftertext</b> modifier requests the same action for captured substrings as 1247well as the main matched substring. In each case the remainder is output on the 1248following line with a plus character following the capture number. 1249</P> 1250<P> 1251The <b>allusedtext</b> modifier requests that all the text that was consulted 1252during a successful pattern match by the interpreter should be shown. This 1253feature is not supported for JIT matching, and if requested with JIT it is 1254ignored (with a warning message). Setting this modifier affects the output if 1255there is a lookbehind at the start of a match, or a lookahead at the end, or if 1256\K is used in the pattern. Characters that precede or follow the start and end 1257of the actual match are indicated in the output by '<' or '>' characters 1258underneath them. Here is an example: 1259<pre> 1260 re> /(?<=pqr)abc(?=xyz)/ 1261 data> 123pqrabcxyz456\=allusedtext 1262 0: pqrabcxyz 1263 <<< >>> 1264</pre> 1265This shows that the matched string is "abc", with the preceding and following 1266strings "pqr" and "xyz" having been consulted during the match (when processing 1267the assertions). 1268</P> 1269<P> 1270The <b>startchar</b> modifier requests that the starting character for the match 1271be indicated, if it is different to the start of the matched string. The only 1272time when this occurs is when \K has been processed as part of the match. In 1273this situation, the output for the matched string is displayed from the 1274starting character instead of from the match point, with circumflex characters 1275under the earlier characters. For example: 1276<pre> 1277 re> /abc\Kxyz/ 1278 data> abcxyz\=startchar 1279 0: abcxyz 1280 ^^^ 1281</pre> 1282Unlike <b>allusedtext</b>, the <b>startchar</b> modifier can be used with JIT. 1283However, these two modifiers are mutually exclusive. 1284</P> 1285<br><b> 1286Showing the value of all capture groups 1287</b><br> 1288<P> 1289The <b>allcaptures</b> modifier requests that the values of all potential 1290captured parentheses be output after a match. By default, only those up to the 1291highest one actually used in the match are output (corresponding to the return 1292code from <b>pcre2_match()</b>). Groups that did not take part in the match 1293are output as "<unset>". This modifier is not relevant for DFA matching (which 1294does no capturing) and does not apply when <b>replace</b> is specified; it is 1295ignored, with a warning message, if present. 1296</P> 1297<br><b> 1298Showing the entire ovector, for all outcomes 1299</b><br> 1300<P> 1301The <b>allvector</b> modifier requests that the entire ovector be shown, 1302whatever the outcome of the match. Compare <b>allcaptures</b>, which shows only 1303up to the maximum number of capture groups for the pattern, and then only for a 1304successful complete non-DFA match. This modifier, which acts after any match 1305result, and also for DFA matching, provides a means of checking that there are 1306no unexpected modifications to ovector fields. Before each match attempt, the 1307ovector is filled with a special value, and if this is found in both elements 1308of a capturing pair, "<unchanged>" is output. After a successful match, this 1309applies to all groups after the maximum capture group for the pattern. In other 1310cases it applies to the entire ovector. After a partial match, the first two 1311elements are the only ones that should be set. After a DFA match, the amount of 1312ovector that is used depends on the number of matches that were found. 1313</P> 1314<br><b> 1315Testing pattern callouts 1316</b><br> 1317<P> 1318A callout function is supplied when <b>pcre2test</b> calls the library matching 1319functions, unless <b>callout_none</b> is specified. Its behaviour can be 1320controlled by various modifiers listed above whose names begin with 1321<b>callout_</b>. Details are given in the section entitled "Callouts" 1322<a href="#callouts">below.</a> 1323Testing callouts from <b>pcre2_substitute()</b> is decribed separately in 1324"Testing the substitution function" 1325<a href="#substitution">below.</a> 1326</P> 1327<br><b> 1328Finding all matches in a string 1329</b><br> 1330<P> 1331Searching for all possible matches within a subject can be requested by the 1332<b>global</b> or <b>altglobal</b> modifier. After finding a match, the matching 1333function is called again to search the remainder of the subject. The difference 1334between <b>global</b> and <b>altglobal</b> is that the former uses the 1335<i>start_offset</i> argument to <b>pcre2_match()</b> or <b>pcre2_dfa_match()</b> 1336to start searching at a new point within the entire string (which is what Perl 1337does), whereas the latter passes over a shortened subject. This makes a 1338difference to the matching process if the pattern begins with a lookbehind 1339assertion (including \b or \B). 1340</P> 1341<P> 1342If an empty string is matched, the next match is done with the 1343PCRE2_NOTEMPTY_ATSTART and PCRE2_ANCHORED flags set, in order to search for 1344another, non-empty, match at the same point in the subject. If this match 1345fails, the start offset is advanced, and the normal match is retried. This 1346imitates the way Perl handles such cases when using the <b>/g</b> modifier or 1347the <b>split()</b> function. Normally, the start offset is advanced by one 1348character, but if the newline convention recognizes CRLF as a newline, and the 1349current character is CR followed by LF, an advance of two characters occurs. 1350</P> 1351<br><b> 1352Testing substring extraction functions 1353</b><br> 1354<P> 1355The <b>copy</b> and <b>get</b> modifiers can be used to test the 1356<b>pcre2_substring_copy_xxx()</b> and <b>pcre2_substring_get_xxx()</b> functions. 1357They can be given more than once, and each can specify a capture group name or 1358number, for example: 1359<pre> 1360 abcd\=copy=1,copy=3,get=G1 1361</pre> 1362If the <b>#subject</b> command is used to set default copy and/or get lists, 1363these can be unset by specifying a negative number to cancel all numbered 1364groups and an empty name to cancel all named groups. 1365</P> 1366<P> 1367The <b>getall</b> modifier tests <b>pcre2_substring_list_get()</b>, which 1368extracts all captured substrings. 1369</P> 1370<P> 1371If the subject line is successfully matched, the substrings extracted by the 1372convenience functions are output with C, G, or L after the string number 1373instead of a colon. This is in addition to the normal full list. The string 1374length (that is, the return from the extraction function) is given in 1375parentheses after each substring, followed by the name when the extraction was 1376by name. 1377<a name="substitution"></a></P> 1378<br><b> 1379Testing the substitution function 1380</b><br> 1381<P> 1382If the <b>replace</b> modifier is set, the <b>pcre2_substitute()</b> function is 1383called instead of one of the matching functions. Note that replacement strings 1384cannot contain commas, because a comma signifies the end of a modifier. This is 1385not thought to be an issue in a test program. 1386</P> 1387<P> 1388Unlike subject strings, <b>pcre2test</b> does not process replacement strings 1389for escape sequences. In UTF mode, a replacement string is checked to see if it 1390is a valid UTF-8 string. If so, it is correctly converted to a UTF string of 1391the appropriate code unit width. If it is not a valid UTF-8 string, the 1392individual code units are copied directly. This provides a means of passing an 1393invalid UTF-8 string for testing purposes. 1394</P> 1395<P> 1396The following modifiers set options (in additional to the normal match options) 1397for <b>pcre2_substitute()</b>: 1398<pre> 1399 global PCRE2_SUBSTITUTE_GLOBAL 1400 substitute_extended PCRE2_SUBSTITUTE_EXTENDED 1401 substitute_overflow_length PCRE2_SUBSTITUTE_OVERFLOW_LENGTH 1402 substitute_unknown_unset PCRE2_SUBSTITUTE_UNKNOWN_UNSET 1403 substitute_unset_empty PCRE2_SUBSTITUTE_UNSET_EMPTY 1404 1405</PRE> 1406</P> 1407<P> 1408After a successful substitution, the modified string is output, preceded by the 1409number of replacements. This may be zero if there were no matches. Here is a 1410simple example of a substitution test: 1411<pre> 1412 /abc/replace=xxx 1413 =abc=abc= 1414 1: =xxx=abc= 1415 =abc=abc=\=global 1416 2: =xxx=xxx= 1417</pre> 1418Subject and replacement strings should be kept relatively short (fewer than 256 1419characters) for substitution tests, as fixed-size buffers are used. To make it 1420easy to test for buffer overflow, if the replacement string starts with a 1421number in square brackets, that number is passed to <b>pcre2_substitute()</b> as 1422the size of the output buffer, with the replacement string starting at the next 1423character. Here is an example that tests the edge case: 1424<pre> 1425 /abc/ 1426 123abc123\=replace=[10]XYZ 1427 1: 123XYZ123 1428 123abc123\=replace=[9]XYZ 1429 Failed: error -47: no more memory 1430</pre> 1431The default action of <b>pcre2_substitute()</b> is to return 1432PCRE2_ERROR_NOMEMORY when the output buffer is too small. However, if the 1433PCRE2_SUBSTITUTE_OVERFLOW_LENGTH option is set (by using the 1434<b>substitute_overflow_length</b> modifier), <b>pcre2_substitute()</b> continues 1435to go through the motions of matching and substituting (but not doing any 1436callouts), in order to compute the size of buffer that is required. When this 1437happens, <b>pcre2test</b> shows the required buffer length (which includes space 1438for the trailing zero) as part of the error message. For example: 1439<pre> 1440 /abc/substitute_overflow_length 1441 123abc123\=replace=[9]XYZ 1442 Failed: error -47: no more memory: 10 code units are needed 1443</pre> 1444A replacement string is ignored with POSIX and DFA matching. Specifying partial 1445matching provokes an error return ("bad option value") from 1446<b>pcre2_substitute()</b>. 1447</P> 1448<br><b> 1449Testing substitute callouts 1450</b><br> 1451<P> 1452If the <b>substitute_callout</b> modifier is set, a substitution callout 1453function is set up. The <b>null_context</b> modifier must not be set, because 1454the address of the callout function is passed in a match context. When the 1455callout function is called (after each substitution), details of the the input 1456and output strings are output. For example: 1457<pre> 1458 /abc/g,replace=<$0>,substitute_callout 1459 abcdefabcpqr 1460 1(1) Old 0 3 "abc" New 0 5 "<abc>" 1461 2(1) Old 6 9 "abc" New 8 13 "<abc>" 1462 2: <abc>def<abc>pqr 1463</pre> 1464The first number on each callout line is the count of matches. The 1465parenthesized number is the number of pairs that are set in the ovector (that 1466is, one more than the number of capturing groups that were set). Then are 1467listed the offsets of the old substring, its contents, and the same for the 1468replacement. 1469</P> 1470<P> 1471By default, the substitution callout function returns zero, which accepts the 1472replacement and causes matching to continue if /g was used. Two further 1473modifiers can be used to test other return values. If <b>substitute_skip</b> is 1474set to a value greater than zero the callout function returns +1 for the match 1475of that number, and similarly <b>substitute_stop</b> returns -1. These cause the 1476replacement to be rejected, and -1 causes no further matching to take place. If 1477either of them are set, <b>substitute_callout</b> is assumed. For example: 1478<pre> 1479 /abc/g,replace=<$0>,substitute_skip=1 1480 abcdefabcpqr 1481 1(1) Old 0 3 "abc" New 0 5 "<abc> SKIPPED" 1482 2(1) Old 6 9 "abc" New 6 11 "<abc>" 1483 2: abcdef<abc>pqr 1484 abcdefabcpqr\=substitute_stop=1 1485 1(1) Old 0 3 "abc" New 0 5 "<abc> STOPPED" 1486 1: abcdefabcpqr 1487</pre> 1488If both are set for the same number, stop takes precedence. Only a single skip 1489or stop is supported, which is sufficient for testing that the feature works. 1490</P> 1491<br><b> 1492Setting the JIT stack size 1493</b><br> 1494<P> 1495The <b>jitstack</b> modifier provides a way of setting the maximum stack size 1496that is used by the just-in-time optimization code. It is ignored if JIT 1497optimization is not being used. The value is a number of kibibytes (units of 14981024 bytes). Setting zero reverts to the default of 32KiB. Providing a stack 1499that is larger than the default is necessary only for very complicated 1500patterns. If <b>jitstack</b> is set non-zero on a subject line it overrides any 1501value that was set on the pattern. 1502</P> 1503<br><b> 1504Setting heap, match, and depth limits 1505</b><br> 1506<P> 1507The <b>heap_limit</b>, <b>match_limit</b>, and <b>depth_limit</b> modifiers set 1508the appropriate limits in the match context. These values are ignored when the 1509<b>find_limits</b> modifier is specified. 1510</P> 1511<br><b> 1512Finding minimum limits 1513</b><br> 1514<P> 1515If the <b>find_limits</b> modifier is present on a subject line, <b>pcre2test</b> 1516calls the relevant matching function several times, setting different values in 1517the match context via <b>pcre2_set_heap_limit()</b>, 1518<b>pcre2_set_match_limit()</b>, or <b>pcre2_set_depth_limit()</b> until it finds 1519the minimum values for each parameter that allows the match to complete without 1520error. If JIT is being used, only the match limit is relevant. 1521</P> 1522<P> 1523When using this modifier, the pattern should not contain any limit settings 1524such as (*LIMIT_MATCH=...) within it. If such a setting is present and is 1525lower than the minimum matching value, the minimum value cannot be found 1526because <b>pcre2_set_match_limit()</b> etc. are only able to reduce the value of 1527an in-pattern limit; they cannot increase it. 1528</P> 1529<P> 1530For non-DFA matching, the minimum <i>depth_limit</i> number is a measure of how 1531much nested backtracking happens (that is, how deeply the pattern's tree is 1532searched). In the case of DFA matching, <i>depth_limit</i> controls the depth of 1533recursive calls of the internal function that is used for handling pattern 1534recursion, lookaround assertions, and atomic groups. 1535</P> 1536<P> 1537For non-DFA matching, the <i>match_limit</i> number is a measure of the amount 1538of backtracking that takes place, and learning the minimum value can be 1539instructive. For most simple matches, the number is quite small, but for 1540patterns with very large numbers of matching possibilities, it can become large 1541very quickly with increasing length of subject string. In the case of DFA 1542matching, <i>match_limit</i> controls the total number of calls, both recursive 1543and non-recursive, to the internal matching function, thus controlling the 1544overall amount of computing resource that is used. 1545</P> 1546<P> 1547For both kinds of matching, the <i>heap_limit</i> number, which is in kibibytes 1548(units of 1024 bytes), limits the amount of heap memory used for matching. A 1549value of zero disables the use of any heap memory; many simple pattern matches 1550can be done without using the heap, so zero is not an unreasonable setting. 1551</P> 1552<br><b> 1553Showing MARK names 1554</b><br> 1555<P> 1556The <b>mark</b> modifier causes the names from backtracking control verbs that 1557are returned from calls to <b>pcre2_match()</b> to be displayed. If a mark is 1558returned for a match, non-match, or partial match, <b>pcre2test</b> shows it. 1559For a match, it is on a line by itself, tagged with "MK:". Otherwise, it 1560is added to the non-match message. 1561</P> 1562<br><b> 1563Showing memory usage 1564</b><br> 1565<P> 1566The <b>memory</b> modifier causes <b>pcre2test</b> to log the sizes of all heap 1567memory allocation and freeing calls that occur during a call to 1568<b>pcre2_match()</b> or <b>pcre2_dfa_match()</b>. These occur only when a match 1569requires a bigger vector than the default for remembering backtracking points 1570(<b>pcre2_match()</b>) or for internal workspace (<b>pcre2_dfa_match()</b>). In 1571many cases there will be no heap memory used and therefore no additional 1572output. No heap memory is allocated during matching with JIT, so in that case 1573the <b>memory</b> modifier never has any effect. For this modifier to work, the 1574<b>null_context</b> modifier must not be set on both the pattern and the 1575subject, though it can be set on one or the other. 1576</P> 1577<br><b> 1578Setting a starting offset 1579</b><br> 1580<P> 1581The <b>offset</b> modifier sets an offset in the subject string at which 1582matching starts. Its value is a number of code units, not characters. 1583</P> 1584<br><b> 1585Setting an offset limit 1586</b><br> 1587<P> 1588The <b>offset_limit</b> modifier sets a limit for unanchored matches. If a match 1589cannot be found starting at or before this offset in the subject, a "no match" 1590return is given. The data value is a number of code units, not characters. When 1591this modifier is used, the <b>use_offset_limit</b> modifier must have been set 1592for the pattern; if not, an error is generated. 1593</P> 1594<br><b> 1595Setting the size of the output vector 1596</b><br> 1597<P> 1598The <b>ovector</b> modifier applies only to the subject line in which it 1599appears, though of course it can also be used to set a default in a 1600<b>#subject</b> command. It specifies the number of pairs of offsets that are 1601available for storing matching information. The default is 15. 1602</P> 1603<P> 1604A value of zero is useful when testing the POSIX API because it causes 1605<b>regexec()</b> to be called with a NULL capture vector. When not testing the 1606POSIX API, a value of zero is used to cause 1607<b>pcre2_match_data_create_from_pattern()</b> to be called, in order to create a 1608match block of exactly the right size for the pattern. (It is not possible to 1609create a match block with a zero-length ovector; there is always at least one 1610pair of offsets.) 1611</P> 1612<br><b> 1613Passing the subject as zero-terminated 1614</b><br> 1615<P> 1616By default, the subject string is passed to a native API matching function with 1617its correct length. In order to test the facility for passing a zero-terminated 1618string, the <b>zero_terminate</b> modifier is provided. It causes the length to 1619be passed as PCRE2_ZERO_TERMINATED. When matching via the POSIX interface, 1620this modifier is ignored, with a warning. 1621</P> 1622<P> 1623When testing <b>pcre2_substitute()</b>, this modifier also has the effect of 1624passing the replacement string as zero-terminated. 1625</P> 1626<br><b> 1627Passing a NULL context 1628</b><br> 1629<P> 1630Normally, <b>pcre2test</b> passes a context block to <b>pcre2_match()</b>, 1631<b>pcre2_dfa_match()</b>, <b>pcre2_jit_match()</b> or <b>pcre2_substitute()</b>. 1632If the <b>null_context</b> modifier is set, however, NULL is passed. This is for 1633testing that the matching and substitution functions behave correctly in this 1634case (they use default values). This modifier cannot be used with the 1635<b>find_limits</b> or <b>substitute_callout</b> modifiers. 1636</P> 1637<br><a name="SEC12" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br> 1638<P> 1639By default, <b>pcre2test</b> uses the standard PCRE2 matching function, 1640<b>pcre2_match()</b> to match each subject line. PCRE2 also supports an 1641alternative matching function, <b>pcre2_dfa_match()</b>, which operates in a 1642different way, and has some restrictions. The differences between the two 1643functions are described in the 1644<a href="pcre2matching.html"><b>pcre2matching</b></a> 1645documentation. 1646</P> 1647<P> 1648If the <b>dfa</b> modifier is set, the alternative matching function is used. 1649This function finds all possible matches at a given point in the subject. If, 1650however, the <b>dfa_shortest</b> modifier is set, processing stops after the 1651first match is found. This is always the shortest possible match. 1652</P> 1653<br><a name="SEC13" href="#TOC1">DEFAULT OUTPUT FROM pcre2test</a><br> 1654<P> 1655This section describes the output when the normal matching function, 1656<b>pcre2_match()</b>, is being used. 1657</P> 1658<P> 1659When a match succeeds, <b>pcre2test</b> outputs the list of captured substrings, 1660starting with number 0 for the string that matched the whole pattern. 1661Otherwise, it outputs "No match" when the return is PCRE2_ERROR_NOMATCH, or 1662"Partial match:" followed by the partially matching substring when the 1663return is PCRE2_ERROR_PARTIAL. (Note that this is the 1664entire substring that was inspected during the partial match; it may include 1665characters before the actual match start if a lookbehind assertion, \K, \b, 1666or \B was involved.) 1667</P> 1668<P> 1669For any other return, <b>pcre2test</b> outputs the PCRE2 negative error number 1670and a short descriptive phrase. If the error is a failed UTF string check, the 1671code unit offset of the start of the failing character is also output. Here is 1672an example of an interactive <b>pcre2test</b> run. 1673<pre> 1674 $ pcre2test 1675 PCRE2 version 10.22 2016-07-29 1676 1677 re> /^abc(\d+)/ 1678 data> abc123 1679 0: abc123 1680 1: 123 1681 data> xyz 1682 No match 1683</pre> 1684Unset capturing substrings that are not followed by one that is set are not 1685shown by <b>pcre2test</b> unless the <b>allcaptures</b> modifier is specified. In 1686the following example, there are two capturing substrings, but when the first 1687data line is matched, the second, unset substring is not shown. An "internal" 1688unset substring is shown as "<unset>", as for the second data line. 1689<pre> 1690 re> /(a)|(b)/ 1691 data> a 1692 0: a 1693 1: a 1694 data> b 1695 0: b 1696 1: <unset> 1697 2: b 1698</pre> 1699If the strings contain any non-printing characters, they are output as \xhh 1700escapes if the value is less than 256 and UTF mode is not set. Otherwise they 1701are output as \x{hh...} escapes. See below for the definition of non-printing 1702characters. If the <b>aftertext</b> modifier is set, the output for substring 17030 is followed by the the rest of the subject string, identified by "0+" like 1704this: 1705<pre> 1706 re> /cat/aftertext 1707 data> cataract 1708 0: cat 1709 0+ aract 1710</pre> 1711If global matching is requested, the results of successive matching attempts 1712are output in sequence, like this: 1713<pre> 1714 re> /\Bi(\w\w)/g 1715 data> Mississippi 1716 0: iss 1717 1: ss 1718 0: iss 1719 1: ss 1720 0: ipp 1721 1: pp 1722</pre> 1723"No match" is output only if the first match attempt fails. Here is an example 1724of a failure message (the offset 4 that is specified by the <b>offset</b> 1725modifier is past the end of the subject string): 1726<pre> 1727 re> /xyz/ 1728 data> xyz\=offset=4 1729 Error -24 (bad offset value) 1730</PRE> 1731</P> 1732<P> 1733Note that whereas patterns can be continued over several lines (a plain ">" 1734prompt is used for continuations), subject lines may not. However newlines can 1735be included in a subject by means of the \n escape (or \r, \r\n, etc., 1736depending on the newline sequence setting). 1737</P> 1738<br><a name="SEC14" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br> 1739<P> 1740When the alternative matching function, <b>pcre2_dfa_match()</b>, is used, the 1741output consists of a list of all the matches that start at the first point in 1742the subject where there is at least one match. For example: 1743<pre> 1744 re> /(tang|tangerine|tan)/ 1745 data> yellow tangerine\=dfa 1746 0: tangerine 1747 1: tang 1748 2: tan 1749</pre> 1750Using the normal matching function on this data finds only "tang". The 1751longest matching string is always given first (and numbered zero). After a 1752PCRE2_ERROR_PARTIAL return, the output is "Partial match:", followed by the 1753partially matching substring. Note that this is the entire substring that was 1754inspected during the partial match; it may include characters before the actual 1755match start if a lookbehind assertion, \b, or \B was involved. (\K is not 1756supported for DFA matching.) 1757</P> 1758<P> 1759If global matching is requested, the search for further matches resumes 1760at the end of the longest match. For example: 1761<pre> 1762 re> /(tang|tangerine|tan)/g 1763 data> yellow tangerine and tangy sultana\=dfa 1764 0: tangerine 1765 1: tang 1766 2: tan 1767 0: tang 1768 1: tan 1769 0: tan 1770</pre> 1771The alternative matching function does not support substring capture, so the 1772modifiers that are concerned with captured substrings are not relevant. 1773</P> 1774<br><a name="SEC15" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br> 1775<P> 1776When the alternative matching function has given the PCRE2_ERROR_PARTIAL 1777return, indicating that the subject partially matched the pattern, you can 1778restart the match with additional subject data by means of the 1779<b>dfa_restart</b> modifier. For example: 1780<pre> 1781 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ 1782 data> 23ja\=P,dfa 1783 Partial match: 23ja 1784 data> n05\=dfa,dfa_restart 1785 0: n05 1786</pre> 1787For further information about partial matching, see the 1788<a href="pcre2partial.html"><b>pcre2partial</b></a> 1789documentation. 1790<a name="callouts"></a></P> 1791<br><a name="SEC16" href="#TOC1">CALLOUTS</a><br> 1792<P> 1793If the pattern contains any callout requests, <b>pcre2test</b>'s callout 1794function is called during matching unless <b>callout_none</b> is specified. This 1795works with both matching functions, and with JIT, though there are some 1796differences in behaviour. The output for callouts with numerical arguments and 1797those with string arguments is slightly different. 1798</P> 1799<br><b> 1800Callouts with numerical arguments 1801</b><br> 1802<P> 1803By default, the callout function displays the callout number, the start and 1804current positions in the subject text at the callout time, and the next pattern 1805item to be tested. For example: 1806<pre> 1807 --->pqrabcdef 1808 0 ^ ^ \d 1809</pre> 1810This output indicates that callout number 0 occurred for a match attempt 1811starting at the fourth character of the subject string, when the pointer was at 1812the seventh character, and when the next pattern item was \d. Just 1813one circumflex is output if the start and current positions are the same, or if 1814the current position precedes the start position, which can happen if the 1815callout is in a lookbehind assertion. 1816</P> 1817<P> 1818Callouts numbered 255 are assumed to be automatic callouts, inserted as a 1819result of the <b>auto_callout</b> pattern modifier. In this case, instead of 1820showing the callout number, the offset in the pattern, preceded by a plus, is 1821output. For example: 1822<pre> 1823 re> /\d?[A-E]\*/auto_callout 1824 data> E* 1825 --->E* 1826 +0 ^ \d? 1827 +3 ^ [A-E] 1828 +8 ^^ \* 1829 +10 ^ ^ 1830 0: E* 1831</pre> 1832If a pattern contains (*MARK) items, an additional line is output whenever 1833a change of latest mark is passed to the callout function. For example: 1834<pre> 1835 re> /a(*MARK:X)bc/auto_callout 1836 data> abc 1837 --->abc 1838 +0 ^ a 1839 +1 ^^ (*MARK:X) 1840 +10 ^^ b 1841 Latest Mark: X 1842 +11 ^ ^ c 1843 +12 ^ ^ 1844 0: abc 1845</pre> 1846The mark changes between matching "a" and "b", but stays the same for the rest 1847of the match, so nothing more is output. If, as a result of backtracking, the 1848mark reverts to being unset, the text "<unset>" is output. 1849</P> 1850<br><b> 1851Callouts with string arguments 1852</b><br> 1853<P> 1854The output for a callout with a string argument is similar, except that instead 1855of outputting a callout number before the position indicators, the callout 1856string and its offset in the pattern string are output before the reflection of 1857the subject string, and the subject string is reflected for each callout. For 1858example: 1859<pre> 1860 re> /^ab(?C'first')cd(?C"second")ef/ 1861 data> abcdefg 1862 Callout (7): 'first' 1863 --->abcdefg 1864 ^ ^ c 1865 Callout (20): "second" 1866 --->abcdefg 1867 ^ ^ e 1868 0: abcdef 1869 1870</PRE> 1871</P> 1872<br><b> 1873Callout modifiers 1874</b><br> 1875<P> 1876The callout function in <b>pcre2test</b> returns zero (carry on matching) by 1877default, but you can use a <b>callout_fail</b> modifier in a subject line to 1878change this and other parameters of the callout (see below). 1879</P> 1880<P> 1881If the <b>callout_capture</b> modifier is set, the current captured groups are 1882output when a callout occurs. This is useful only for non-DFA matching, as 1883<b>pcre2_dfa_match()</b> does not support capturing, so no captures are ever 1884shown. 1885</P> 1886<P> 1887The normal callout output, showing the callout number or pattern offset (as 1888described above) is suppressed if the <b>callout_no_where</b> modifier is set. 1889</P> 1890<P> 1891When using the interpretive matching function <b>pcre2_match()</b> without JIT, 1892setting the <b>callout_extra</b> modifier causes additional output from 1893<b>pcre2test</b>'s callout function to be generated. For the first callout in a 1894match attempt at a new starting position in the subject, "New match attempt" is 1895output. If there has been a backtrack since the last callout (or start of 1896matching if this is the first callout), "Backtrack" is output, followed by "No 1897other matching paths" if the backtrack ended the previous match attempt. For 1898example: 1899<pre> 1900 re> /(a+)b/auto_callout,no_start_optimize,no_auto_possess 1901 data> aac\=callout_extra 1902 New match attempt 1903 --->aac 1904 +0 ^ ( 1905 +1 ^ a+ 1906 +3 ^ ^ ) 1907 +4 ^ ^ b 1908 Backtrack 1909 --->aac 1910 +3 ^^ ) 1911 +4 ^^ b 1912 Backtrack 1913 No other matching paths 1914 New match attempt 1915 --->aac 1916 +0 ^ ( 1917 +1 ^ a+ 1918 +3 ^^ ) 1919 +4 ^^ b 1920 Backtrack 1921 No other matching paths 1922 New match attempt 1923 --->aac 1924 +0 ^ ( 1925 +1 ^ a+ 1926 Backtrack 1927 No other matching paths 1928 New match attempt 1929 --->aac 1930 +0 ^ ( 1931 +1 ^ a+ 1932 No match 1933</pre> 1934Notice that various optimizations must be turned off if you want all possible 1935matching paths to be scanned. If <b>no_start_optimize</b> is not used, there is 1936an immediate "no match", without any callouts, because the starting 1937optimization fails to find "b" in the subject, which it knows must be present 1938for any match. If <b>no_auto_possess</b> is not used, the "a+" item is turned 1939into "a++", which reduces the number of backtracks. 1940</P> 1941<P> 1942The <b>callout_extra</b> modifier has no effect if used with the DFA matching 1943function, or with JIT. 1944</P> 1945<br><b> 1946Return values from callouts 1947</b><br> 1948<P> 1949The default return from the callout function is zero, which allows matching to 1950continue. The <b>callout_fail</b> modifier can be given one or two numbers. If 1951there is only one number, 1 is returned instead of 0 (causing matching to 1952backtrack) when a callout of that number is reached. If two numbers (<n>:<m>) 1953are given, 1 is returned when callout <n> is reached and there have been at 1954least <m> callouts. The <b>callout_error</b> modifier is similar, except that 1955PCRE2_ERROR_CALLOUT is returned, causing the entire matching process to be 1956aborted. If both these modifiers are set for the same callout number, 1957<b>callout_error</b> takes precedence. Note that callouts with string arguments 1958are always given the number zero. 1959</P> 1960<P> 1961The <b>callout_data</b> modifier can be given an unsigned or a negative number. 1962This is set as the "user data" that is passed to the matching function, and 1963passed back when the callout function is invoked. Any value other than zero is 1964used as a return from <b>pcre2test</b>'s callout function. 1965</P> 1966<P> 1967Inserting callouts can be helpful when using <b>pcre2test</b> to check 1968complicated regular expressions. For further information about callouts, see 1969the 1970<a href="pcre2callout.html"><b>pcre2callout</b></a> 1971documentation. 1972</P> 1973<br><a name="SEC17" href="#TOC1">NON-PRINTING CHARACTERS</a><br> 1974<P> 1975When <b>pcre2test</b> is outputting text in the compiled version of a pattern, 1976bytes other than 32-126 are always treated as non-printing characters and are 1977therefore shown as hex escapes. 1978</P> 1979<P> 1980When <b>pcre2test</b> is outputting text that is a matched part of a subject 1981string, it behaves in the same way, unless a different locale has been set for 1982the pattern (using the <b>locale</b> modifier). In this case, the 1983<b>isprint()</b> function is used to distinguish printing and non-printing 1984characters. 1985<a name="saverestore"></a></P> 1986<br><a name="SEC18" href="#TOC1">SAVING AND RESTORING COMPILED PATTERNS</a><br> 1987<P> 1988It is possible to save compiled patterns on disc or elsewhere, and reload them 1989later, subject to a number of restrictions. JIT data cannot be saved. The host 1990on which the patterns are reloaded must be running the same version of PCRE2, 1991with the same code unit width, and must also have the same endianness, pointer 1992width and PCRE2_SIZE type. Before compiled patterns can be saved they must be 1993serialized, that is, converted to a stream of bytes. A single byte stream may 1994contain any number of compiled patterns, but they must all use the same 1995character tables. A single copy of the tables is included in the byte stream 1996(its size is 1088 bytes). 1997</P> 1998<P> 1999The functions whose names begin with <b>pcre2_serialize_</b> are used 2000for serializing and de-serializing. They are described in the 2001<a href="pcre2serialize.html"><b>pcre2serialize</b></a> 2002documentation. In this section we describe the features of <b>pcre2test</b> that 2003can be used to test these functions. 2004</P> 2005<P> 2006Note that "serialization" in PCRE2 does not convert compiled patterns to an 2007abstract format like Java or .NET. It just makes a reloadable byte code stream. 2008Hence the restrictions on reloading mentioned above. 2009</P> 2010<P> 2011In <b>pcre2test</b>, when a pattern with <b>push</b> modifier is successfully 2012compiled, it is pushed onto a stack of compiled patterns, and <b>pcre2test</b> 2013expects the next line to contain a new pattern (or command) instead of a 2014subject line. By contrast, the <b>pushcopy</b> modifier causes a copy of the 2015compiled pattern to be stacked, leaving the original available for immediate 2016matching. By using <b>push</b> and/or <b>pushcopy</b>, a number of patterns can 2017be compiled and retained. These modifiers are incompatible with <b>posix</b>, 2018and control modifiers that act at match time are ignored (with a message) for 2019the stacked patterns. The <b>jitverify</b> modifier applies only at compile 2020time. 2021</P> 2022<P> 2023The command 2024<pre> 2025 #save <filename> 2026</pre> 2027causes all the stacked patterns to be serialized and the result written to the 2028named file. Afterwards, all the stacked patterns are freed. The command 2029<pre> 2030 #load <filename> 2031</pre> 2032reads the data in the file, and then arranges for it to be de-serialized, with 2033the resulting compiled patterns added to the pattern stack. The pattern on the 2034top of the stack can be retrieved by the #pop command, which must be followed 2035by lines of subjects that are to be matched with the pattern, terminated as 2036usual by an empty line or end of file. This command may be followed by a 2037modifier list containing only 2038<a href="#controlmodifiers">control modifiers</a> 2039that act after a pattern has been compiled. In particular, <b>hex</b>, 2040<b>posix</b>, <b>posix_nosub</b>, <b>push</b>, and <b>pushcopy</b> are not allowed, 2041nor are any 2042<a href="#optionmodifiers">option-setting modifiers.</a> 2043The JIT modifiers are, however permitted. Here is an example that saves and 2044reloads two patterns. 2045<pre> 2046 /abc/push 2047 /xyz/push 2048 #save tempfile 2049 #load tempfile 2050 #pop info 2051 xyz 2052 2053 #pop jit,bincode 2054 abc 2055</pre> 2056If <b>jitverify</b> is used with #pop, it does not automatically imply 2057<b>jit</b>, which is different behaviour from when it is used on a pattern. 2058</P> 2059<P> 2060The #popcopy command is analagous to the <b>pushcopy</b> modifier in that it 2061makes current a copy of the topmost stack pattern, leaving the original still 2062on the stack. 2063</P> 2064<br><a name="SEC19" href="#TOC1">SEE ALSO</a><br> 2065<P> 2066<b>pcre2</b>(3), <b>pcre2api</b>(3), <b>pcre2callout</b>(3), 2067<b>pcre2jit</b>, <b>pcre2matching</b>(3), <b>pcre2partial</b>(d), 2068<b>pcre2pattern</b>(3), <b>pcre2serialize</b>(3). 2069</P> 2070<br><a name="SEC20" href="#TOC1">AUTHOR</a><br> 2071<P> 2072Philip Hazel 2073<br> 2074University Computing Service 2075<br> 2076Cambridge, England. 2077<br> 2078</P> 2079<br><a name="SEC21" href="#TOC1">REVISION</a><br> 2080<P> 2081Last updated: 11 March 2019 2082<br> 2083Copyright © 1997-2019 University of Cambridge. 2084<br> 2085<p> 2086Return to the <a href="index.html">PCRE2 index page</a>. 2087</p> 2088