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 /x extended set PCRE2_EXTENDED 610 /xx extended_more set PCRE2_EXTENDED_MORE 611 firstline set PCRE2_FIRSTLINE 612 literal set PCRE2_LITERAL 613 match_line set PCRE2_EXTRA_MATCH_LINE 614 match_unset_backref set PCRE2_MATCH_UNSET_BACKREF 615 match_word set PCRE2_EXTRA_MATCH_WORD 616 /m multiline set PCRE2_MULTILINE 617 never_backslash_c set PCRE2_NEVER_BACKSLASH_C 618 never_ucp set PCRE2_NEVER_UCP 619 never_utf set PCRE2_NEVER_UTF 620 /n no_auto_capture set PCRE2_NO_AUTO_CAPTURE 621 no_auto_possess set PCRE2_NO_AUTO_POSSESS 622 no_dotstar_anchor set PCRE2_NO_DOTSTAR_ANCHOR 623 no_start_optimize set PCRE2_NO_START_OPTIMIZE 624 no_utf_check set PCRE2_NO_UTF_CHECK 625 ucp set PCRE2_UCP 626 ungreedy set PCRE2_UNGREEDY 627 use_offset_limit set PCRE2_USE_OFFSET_LIMIT 628 utf set PCRE2_UTF 629</pre> 630As well as turning on the PCRE2_UTF option, the <b>utf</b> modifier causes all 631non-printing characters in output strings to be printed using the \x{hh...} 632notation. Otherwise, those less than 0x100 are output in hex without the curly 633brackets. Setting <b>utf</b> in 16-bit or 32-bit mode also causes pattern and 634subject strings to be translated to UTF-16 or UTF-32, respectively, before 635being passed to library functions. 636<a name="controlmodifiers"></a></P> 637<br><b> 638Setting compilation controls 639</b><br> 640<P> 641The following modifiers affect the compilation process or request information 642about the pattern. There are single-letter abbreviations for some that are 643heavily used in the test files. 644<pre> 645 bsr=[anycrlf|unicode] specify \R handling 646 /B bincode show binary code without lengths 647 callout_info show callout information 648 convert=<options> request foreign pattern conversion 649 convert_glob_escape=c set glob escape character 650 convert_glob_separator=c set glob separator character 651 convert_length set convert buffer length 652 debug same as info,fullbincode 653 framesize show matching frame size 654 fullbincode show binary code with lengths 655 /I info show info about compiled pattern 656 hex unquoted characters are hexadecimal 657 jit[=<number>] use JIT 658 jitfast use JIT fast path 659 jitverify verify JIT use 660 locale=<name> use this locale 661 max_pattern_length=<n> set the maximum pattern length 662 memory show memory used 663 newline=<type> set newline type 664 null_context compile with a NULL context 665 parens_nest_limit=<n> set maximum parentheses depth 666 posix use the POSIX API 667 posix_nosub use the POSIX API with REG_NOSUB 668 push push compiled pattern onto the stack 669 pushcopy push a copy onto the stack 670 stackguard=<number> test the stackguard feature 671 subject_literal treat all subject lines as literal 672 tables=[0|1|2] select internal tables 673 use_length do not zero-terminate the pattern 674 utf8_input treat input as UTF-8 675</pre> 676The effects of these modifiers are described in the following sections. 677</P> 678<br><b> 679Newline and \R handling 680</b><br> 681<P> 682The <b>bsr</b> modifier specifies what \R in a pattern should match. If it is 683set to "anycrlf", \R matches CR, LF, or CRLF only. If it is set to "unicode", 684\R matches any Unicode newline sequence. The default can be specified when 685PCRE2 is built; if it is not, the default is set to Unicode. 686</P> 687<P> 688The <b>newline</b> modifier specifies which characters are to be interpreted as 689newlines, both in the pattern and in subject lines. The type must be one of CR, 690LF, CRLF, ANYCRLF, ANY, or NUL (in upper or lower case). 691</P> 692<br><b> 693Information about a pattern 694</b><br> 695<P> 696The <b>debug</b> modifier is a shorthand for <b>info,fullbincode</b>, requesting 697all available information. 698</P> 699<P> 700The <b>bincode</b> modifier causes a representation of the compiled code to be 701output after compilation. This information does not contain length and offset 702values, which ensures that the same output is generated for different internal 703link sizes and different code unit widths. By using <b>bincode</b>, the same 704regression tests can be used in different environments. 705</P> 706<P> 707The <b>fullbincode</b> modifier, by contrast, <i>does</i> include length and 708offset values. This is used in a few special tests that run only for specific 709code unit widths and link sizes, and is also useful for one-off tests. 710</P> 711<P> 712The <b>info</b> modifier requests information about the compiled pattern 713(whether it is anchored, has a fixed first character, and so on). The 714information is obtained from the <b>pcre2_pattern_info()</b> function. Here are 715some typical examples: 716<pre> 717 re> /(?i)(^a|^b)/m,info 718 Capturing subpattern count = 1 719 Compile options: multiline 720 Overall options: caseless multiline 721 First code unit at start or follows newline 722 Subject length lower bound = 1 723 724 re> /(?i)abc/info 725 Capturing subpattern count = 0 726 Compile options: <none> 727 Overall options: caseless 728 First code unit = 'a' (caseless) 729 Last code unit = 'c' (caseless) 730 Subject length lower bound = 3 731</pre> 732"Compile options" are those specified by modifiers; "overall options" have 733added options that are taken or deduced from the pattern. If both sets of 734options are the same, just a single "options" line is output; if there are no 735options, the line is omitted. "First code unit" is where any match must start; 736if there is more than one they are listed as "starting code units". "Last code 737unit" is the last literal code unit that must be present in any match. This is 738not necessarily the last character. These lines are omitted if no starting or 739ending code units are recorded. 740</P> 741<P> 742The <b>framesize</b> modifier shows the size, in bytes, of the storage frames 743used by <b>pcre2_match()</b> for handling backtracking. The size depends on the 744number of capturing parentheses in the pattern. 745</P> 746<P> 747The <b>callout_info</b> modifier requests information about all the callouts in 748the pattern. A list of them is output at the end of any other information that 749is requested. For each callout, either its number or string is given, followed 750by the item that follows it in the pattern. 751</P> 752<br><b> 753Passing a NULL context 754</b><br> 755<P> 756Normally, <b>pcre2test</b> passes a context block to <b>pcre2_compile()</b>. If 757the <b>null_context</b> modifier is set, however, NULL is passed. This is for 758testing that <b>pcre2_compile()</b> behaves correctly in this case (it uses 759default values). 760</P> 761<br><b> 762Specifying pattern characters in hexadecimal 763</b><br> 764<P> 765The <b>hex</b> modifier specifies that the characters of the pattern, except for 766substrings enclosed in single or double quotes, are to be interpreted as pairs 767of hexadecimal digits. This feature is provided as a way of creating patterns 768that contain binary zeros and other non-printing characters. White space is 769permitted between pairs of digits. For example, this pattern contains three 770characters: 771<pre> 772 /ab 32 59/hex 773</pre> 774Parts of such a pattern are taken literally if quoted. This pattern contains 775nine characters, only two of which are specified in hexadecimal: 776<pre> 777 /ab "literal" 32/hex 778</pre> 779Either single or double quotes may be used. There is no way of including 780the delimiter within a substring. The <b>hex</b> and <b>expand</b> modifiers are 781mutually exclusive. 782</P> 783<br><b> 784Specifying the pattern's length 785</b><br> 786<P> 787By default, patterns are passed to the compiling functions as zero-terminated 788strings but can be passed by length instead of being zero-terminated. The 789<b>use_length</b> modifier causes this to happen. Using a length happens 790automatically (whether or not <b>use_length</b> is set) when <b>hex</b> is set, 791because patterns specified in hexadecimal may contain binary zeros. 792</P> 793<P> 794If <b>hex</b> or <b>use_length</b> is used with the POSIX wrapper API (see 795<a href="#posixwrapper">"Using the POSIX wrapper API"</a> 796below), the REG_PEND extension is used to pass the pattern's length. 797</P> 798<br><b> 799Specifying wide characters in 16-bit and 32-bit modes 800</b><br> 801<P> 802In 16-bit and 32-bit modes, all input is automatically treated as UTF-8 and 803translated to UTF-16 or UTF-32 when the <b>utf</b> modifier is set. For testing 804the 16-bit and 32-bit libraries in non-UTF mode, the <b>utf8_input</b> modifier 805can be used. It is mutually exclusive with <b>utf</b>. Input lines are 806interpreted as UTF-8 as a means of specifying wide characters. More details are 807given in 808<a href="#inputencoding">"Input encoding"</a> 809above. 810</P> 811<br><b> 812Generating long repetitive patterns 813</b><br> 814<P> 815Some tests use long patterns that are very repetitive. Instead of creating a 816very long input line for such a pattern, you can use a special repetition 817feature, similar to the one described for subject lines above. If the 818<b>expand</b> modifier is present on a pattern, parts of the pattern that have 819the form 820<pre> 821 \[<characters>]{<count>} 822</pre> 823are expanded before the pattern is passed to <b>pcre2_compile()</b>. For 824example, \[AB]{6000} is expanded to "ABAB..." 6000 times. This construction 825cannot be nested. An initial "\[" sequence is recognized only if "]{" followed 826by decimal digits and "}" is found later in the pattern. If not, the characters 827remain in the pattern unaltered. The <b>expand</b> and <b>hex</b> modifiers are 828mutually exclusive. 829</P> 830<P> 831If part of an expanded pattern looks like an expansion, but is really part of 832the actual pattern, unwanted expansion can be avoided by giving two values in 833the quantifier. For example, \[AB]{6000,6000} is not recognized as an 834expansion item. 835</P> 836<P> 837If the <b>info</b> modifier is set on an expanded pattern, the result of the 838expansion is included in the information that is output. 839</P> 840<br><b> 841JIT compilation 842</b><br> 843<P> 844Just-in-time (JIT) compiling is a heavyweight optimization that can greatly 845speed up pattern matching. See the 846<a href="pcre2jit.html"><b>pcre2jit</b></a> 847documentation for details. JIT compiling happens, optionally, after a pattern 848has been successfully compiled into an internal form. The JIT compiler converts 849this to optimized machine code. It needs to know whether the match-time options 850PCRE2_PARTIAL_HARD and PCRE2_PARTIAL_SOFT are going to be used, because 851different code is generated for the different cases. See the <b>partial</b> 852modifier in "Subject Modifiers" 853<a href="#subjectmodifiers">below</a> 854for details of how these options are specified for each match attempt. 855</P> 856<P> 857JIT compilation is requested by the <b>jit</b> pattern modifier, which may 858optionally be followed by an equals sign and a number in the range 0 to 7. 859The three bits that make up the number specify which of the three JIT operating 860modes are to be compiled: 861<pre> 862 1 compile JIT code for non-partial matching 863 2 compile JIT code for soft partial matching 864 4 compile JIT code for hard partial matching 865</pre> 866The possible values for the <b>jit</b> modifier are therefore: 867<pre> 868 0 disable JIT 869 1 normal matching only 870 2 soft partial matching only 871 3 normal and soft partial matching 872 4 hard partial matching only 873 6 soft and hard partial matching only 874 7 all three modes 875</pre> 876If no number is given, 7 is assumed. The phrase "partial matching" means a call 877to <b>pcre2_match()</b> with either the PCRE2_PARTIAL_SOFT or the 878PCRE2_PARTIAL_HARD option set. Note that such a call may return a complete 879match; the options enable the possibility of a partial match, but do not 880require it. Note also that if you request JIT compilation only for partial 881matching (for example, jit=2) but do not set the <b>partial</b> modifier on a 882subject line, that match will not use JIT code because none was compiled for 883non-partial matching. 884</P> 885<P> 886If JIT compilation is successful, the compiled JIT code will automatically be 887used when an appropriate type of match is run, except when incompatible 888run-time options are specified. For more details, see the 889<a href="pcre2jit.html"><b>pcre2jit</b></a> 890documentation. See also the <b>jitstack</b> modifier below for a way of 891setting the size of the JIT stack. 892</P> 893<P> 894If the <b>jitfast</b> modifier is specified, matching is done using the JIT 895"fast path" interface, <b>pcre2_jit_match()</b>, which skips some of the sanity 896checks that are done by <b>pcre2_match()</b>, and of course does not work when 897JIT is not supported. If <b>jitfast</b> is specified without <b>jit</b>, jit=7 is 898assumed. 899</P> 900<P> 901If the <b>jitverify</b> modifier is specified, information about the compiled 902pattern shows whether JIT compilation was or was not successful. If 903<b>jitverify</b> is specified without <b>jit</b>, jit=7 is assumed. If JIT 904compilation is successful when <b>jitverify</b> is set, the text "(JIT)" is 905added to the first output line after a match or non match when JIT-compiled 906code was actually used in the match. 907</P> 908<br><b> 909Setting a locale 910</b><br> 911<P> 912The <b>locale</b> modifier must specify the name of a locale, for example: 913<pre> 914 /pattern/locale=fr_FR 915</pre> 916The given locale is set, <b>pcre2_maketables()</b> is called to build a set of 917character tables for the locale, and this is then passed to 918<b>pcre2_compile()</b> when compiling the regular expression. The same tables 919are used when matching the following subject lines. The <b>locale</b> modifier 920applies only to the pattern on which it appears, but can be given in a 921<b>#pattern</b> command if a default is needed. Setting a locale and alternate 922character tables are mutually exclusive. 923</P> 924<br><b> 925Showing pattern memory 926</b><br> 927<P> 928The <b>memory</b> modifier causes the size in bytes of the memory used to hold 929the compiled pattern to be output. This does not include the size of the 930<b>pcre2_code</b> block; it is just the actual compiled data. If the pattern is 931subsequently passed to the JIT compiler, the size of the JIT compiled code is 932also output. Here is an example: 933<pre> 934 re> /a(b)c/jit,memory 935 Memory allocation (code space): 21 936 Memory allocation (JIT code): 1910 937 938</PRE> 939</P> 940<br><b> 941Limiting nested parentheses 942</b><br> 943<P> 944The <b>parens_nest_limit</b> modifier sets a limit on the depth of nested 945parentheses in a pattern. Breaching the limit causes a compilation error. 946The default for the library is set when PCRE2 is built, but <b>pcre2test</b> 947sets its own default of 220, which is required for running the standard test 948suite. 949</P> 950<br><b> 951Limiting the pattern length 952</b><br> 953<P> 954The <b>max_pattern_length</b> modifier sets a limit, in code units, to the 955length of pattern that <b>pcre2_compile()</b> will accept. Breaching the limit 956causes a compilation error. The default is the largest number a PCRE2_SIZE 957variable can hold (essentially unlimited). 958<a name="posixwrapper"></a></P> 959<br><b> 960Using the POSIX wrapper API 961</b><br> 962<P> 963The <b>posix</b> and <b>posix_nosub</b> modifiers cause <b>pcre2test</b> to call 964PCRE2 via the POSIX wrapper API rather than its native API. When 965<b>posix_nosub</b> is used, the POSIX option REG_NOSUB is passed to 966<b>regcomp()</b>. The POSIX wrapper supports only the 8-bit library. Note that 967it does not imply POSIX matching semantics; for more detail see the 968<a href="pcre2posix.html"><b>pcre2posix</b></a> 969documentation. The following pattern modifiers set options for the 970<b>regcomp()</b> function: 971<pre> 972 caseless REG_ICASE 973 multiline REG_NEWLINE 974 dotall REG_DOTALL ) 975 ungreedy REG_UNGREEDY ) These options are not part of 976 ucp REG_UCP ) the POSIX standard 977 utf REG_UTF8 ) 978</pre> 979The <b>regerror_buffsize</b> modifier specifies a size for the error buffer that 980is passed to <b>regerror()</b> in the event of a compilation error. For example: 981<pre> 982 /abc/posix,regerror_buffsize=20 983</pre> 984This provides a means of testing the behaviour of <b>regerror()</b> when the 985buffer is too small for the error message. If this modifier has not been set, a 986large buffer is used. 987</P> 988<P> 989The <b>aftertext</b> and <b>allaftertext</b> subject modifiers work as described 990below. All other modifiers are either ignored, with a warning message, or cause 991an error. 992</P> 993<P> 994The pattern is passed to <b>regcomp()</b> as a zero-terminated string by 995default, but if the <b>use_length</b> or <b>hex</b> modifiers are set, the 996REG_PEND extension is used to pass it by length. 997</P> 998<br><b> 999Testing the stack guard feature 1000</b><br> 1001<P> 1002The <b>stackguard</b> modifier is used to test the use of 1003<b>pcre2_set_compile_recursion_guard()</b>, a function that is provided to 1004enable stack availability to be checked during compilation (see the 1005<a href="pcre2api.html"><b>pcre2api</b></a> 1006documentation for details). If the number specified by the modifier is greater 1007than zero, <b>pcre2_set_compile_recursion_guard()</b> is called to set up 1008callback from <b>pcre2_compile()</b> to a local function. The argument it 1009receives is the current nesting parenthesis depth; if this is greater than the 1010value given by the modifier, non-zero is returned, causing the compilation to 1011be aborted. 1012</P> 1013<br><b> 1014Using alternative character tables 1015</b><br> 1016<P> 1017The value specified for the <b>tables</b> modifier must be one of the digits 0, 10181, or 2. It causes a specific set of built-in character tables to be passed to 1019<b>pcre2_compile()</b>. This is used in the PCRE2 tests to check behaviour with 1020different character tables. The digit specifies the tables as follows: 1021<pre> 1022 0 do not pass any special character tables 1023 1 the default ASCII tables, as distributed in 1024 pcre2_chartables.c.dist 1025 2 a set of tables defining ISO 8859 characters 1026</pre> 1027In table 2, some characters whose codes are greater than 128 are identified as 1028letters, digits, spaces, etc. Setting alternate character tables and a locale 1029are mutually exclusive. 1030</P> 1031<br><b> 1032Setting certain match controls 1033</b><br> 1034<P> 1035The following modifiers are really subject modifiers, and are described under 1036"Subject Modifiers" below. However, they may be included in a pattern's 1037modifier list, in which case they are applied to every subject line that is 1038processed with that pattern. These modifiers do not affect the compilation 1039process. 1040<pre> 1041 aftertext show text after match 1042 allaftertext show text after captures 1043 allcaptures show all captures 1044 allusedtext show all consulted text 1045 altglobal alternative global matching 1046 /g global global matching 1047 jitstack=<n> set size of JIT stack 1048 mark show mark values 1049 replace=<string> specify a replacement string 1050 startchar show starting character when relevant 1051 substitute_extended use PCRE2_SUBSTITUTE_EXTENDED 1052 substitute_overflow_length use PCRE2_SUBSTITUTE_OVERFLOW_LENGTH 1053 substitute_unknown_unset use PCRE2_SUBSTITUTE_UNKNOWN_UNSET 1054 substitute_unset_empty use PCRE2_SUBSTITUTE_UNSET_EMPTY 1055</pre> 1056These modifiers may not appear in a <b>#pattern</b> command. If you want them as 1057defaults, set them in a <b>#subject</b> command. 1058</P> 1059<br><b> 1060Specifying literal subject lines 1061</b><br> 1062<P> 1063If the <b>subject_literal</b> modifier is present on a pattern, all the subject 1064lines that it matches are taken as literal strings, with no interpretation of 1065backslashes. It is not possible to set subject modifiers on such lines, but any 1066that are set as defaults by a <b>#subject</b> command are recognized. 1067</P> 1068<br><b> 1069Saving a compiled pattern 1070</b><br> 1071<P> 1072When a pattern with the <b>push</b> modifier is successfully compiled, it is 1073pushed onto a stack of compiled patterns, and <b>pcre2test</b> expects the next 1074line to contain a new pattern (or a command) instead of a subject line. This 1075facility is used when saving compiled patterns to a file, as described in the 1076section entitled "Saving and restoring compiled patterns" 1077<a href="#saverestore">below.</a> 1078If <b>pushcopy</b> is used instead of <b>push</b>, a copy of the compiled 1079pattern is stacked, leaving the original as current, ready to match the 1080following input lines. This provides a way of testing the 1081<b>pcre2_code_copy()</b> function. 1082The <b>push</b> and <b>pushcopy </b> modifiers are incompatible with compilation 1083modifiers such as <b>global</b> that act at match time. Any that are specified 1084are ignored (for the stacked copy), with a warning message, except for 1085<b>replace</b>, which causes an error. Note that <b>jitverify</b>, which is 1086allowed, does not carry through to any subsequent matching that uses a stacked 1087pattern. 1088</P> 1089<br><b> 1090Testing foreign pattern conversion 1091</b><br> 1092<P> 1093The experimental foreign pattern conversion functions in PCRE2 can be tested by 1094setting the <b>convert</b> modifier. Its argument is a colon-separated list of 1095options, which set the equivalent option for the <b>pcre2_pattern_convert()</b> 1096function: 1097<pre> 1098 glob PCRE2_CONVERT_GLOB 1099 glob_no_starstar PCRE2_CONVERT_GLOB_NO_STARSTAR 1100 glob_no_wild_separator PCRE2_CONVERT_GLOB_NO_WILD_SEPARATOR 1101 posix_basic PCRE2_CONVERT_POSIX_BASIC 1102 posix_extended PCRE2_CONVERT_POSIX_EXTENDED 1103 unset Unset all options 1104</pre> 1105The "unset" value is useful for turning off a default that has been set by a 1106<b>#pattern</b> command. When one of these options is set, the input pattern is 1107passed to <b>pcre2_pattern_convert()</b>. If the conversion is successful, the 1108result is reflected in the output and then passed to <b>pcre2_compile()</b>. The 1109normal <b>utf</b> and <b>no_utf_check</b> options, if set, cause the 1110PCRE2_CONVERT_UTF and PCRE2_CONVERT_NO_UTF_CHECK options to be passed to 1111<b>pcre2_pattern_convert()</b>. 1112</P> 1113<P> 1114By default, the conversion function is allowed to allocate a buffer for its 1115output. However, if the <b>convert_length</b> modifier is set to a value greater 1116than zero, <b>pcre2test</b> passes a buffer of the given length. This makes it 1117possible to test the length check. 1118</P> 1119<P> 1120The <b>convert_glob_escape</b> and <b>convert_glob_separator</b> modifiers can be 1121used to specify the escape and separator characters for glob processing, 1122overriding the defaults, which are operating-system dependent. 1123<a name="subjectmodifiers"></a></P> 1124<br><a name="SEC11" href="#TOC1">SUBJECT MODIFIERS</a><br> 1125<P> 1126The modifiers that can appear in subject lines and the <b>#subject</b> 1127command are of two types. 1128</P> 1129<br><b> 1130Setting match options 1131</b><br> 1132<P> 1133The following modifiers set options for <b>pcre2_match()</b> or 1134<b>pcre2_dfa_match()</b>. See 1135<a href="pcreapi.html"><b>pcreapi</b></a> 1136for a description of their effects. 1137<pre> 1138 anchored set PCRE2_ANCHORED 1139 endanchored set PCRE2_ENDANCHORED 1140 dfa_restart set PCRE2_DFA_RESTART 1141 dfa_shortest set PCRE2_DFA_SHORTEST 1142 no_jit set PCRE2_NO_JIT 1143 no_utf_check set PCRE2_NO_UTF_CHECK 1144 notbol set PCRE2_NOTBOL 1145 notempty set PCRE2_NOTEMPTY 1146 notempty_atstart set PCRE2_NOTEMPTY_ATSTART 1147 noteol set PCRE2_NOTEOL 1148 partial_hard (or ph) set PCRE2_PARTIAL_HARD 1149 partial_soft (or ps) set PCRE2_PARTIAL_SOFT 1150</pre> 1151The partial matching modifiers are provided with abbreviations because they 1152appear frequently in tests. 1153</P> 1154<P> 1155If the <b>posix</b> or <b>posix_nosub</b> modifier was present on the pattern, 1156causing the POSIX wrapper API to be used, the only option-setting modifiers 1157that have any effect are <b>notbol</b>, <b>notempty</b>, and <b>noteol</b>, 1158causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively, to be passed to 1159<b>regexec()</b>. The other modifiers are ignored, with a warning message. 1160</P> 1161<P> 1162There is one additional modifier that can be used with the POSIX wrapper. It is 1163ignored (with a warning) if used for non-POSIX matching. 1164<pre> 1165 posix_startend=<n>[:<m>] 1166</pre> 1167This causes the subject string to be passed to <b>regexec()</b> using the 1168REG_STARTEND option, which uses offsets to specify which part of the string is 1169searched. If only one number is given, the end offset is passed as the end of 1170the subject string. For more detail of REG_STARTEND, see the 1171<a href="pcre2posix.html"><b>pcre2posix</b></a> 1172documentation. If the subject string contains binary zeros (coded as escapes 1173such as \x{00} because <b>pcre2test</b> does not support actual binary zeros in 1174its input), you must use <b>posix_startend</b> to specify its length. 1175</P> 1176<br><b> 1177Setting match controls 1178</b><br> 1179<P> 1180The following modifiers affect the matching process or request additional 1181information. Some of them may also be specified on a pattern line (see above), 1182in which case they apply to every subject line that is matched against that 1183pattern. 1184<pre> 1185 aftertext show text after match 1186 allaftertext show text after captures 1187 allcaptures show all captures 1188 allusedtext show all consulted text (non-JIT only) 1189 altglobal alternative global matching 1190 callout_capture show captures at callout time 1191 callout_data=<n> set a value to pass via callouts 1192 callout_error=<n>[:<m>] control callout error 1193 callout_extra show extra callout information 1194 callout_fail=<n>[:<m>] control callout failure 1195 callout_no_where do not show position of a callout 1196 callout_none do not supply a callout function 1197 copy=<number or name> copy captured substring 1198 depth_limit=<n> set a depth limit 1199 dfa use <b>pcre2_dfa_match()</b> 1200 find_limits find match and depth limits 1201 get=<number or name> extract captured substring 1202 getall extract all captured substrings 1203 /g global global matching 1204 heap_limit=<n> set a limit on heap memory (Kbytes) 1205 jitstack=<n> set size of JIT stack 1206 mark show mark values 1207 match_limit=<n> set a match limit 1208 memory show heap memory usage 1209 null_context match with a NULL context 1210 offset=<n> set starting offset 1211 offset_limit=<n> set offset limit 1212 ovector=<n> set size of output vector 1213 recursion_limit=<n> obsolete synonym for depth_limit 1214 replace=<string> specify a replacement string 1215 startchar show startchar when relevant 1216 startoffset=<n> same as offset=<n> 1217 substitute_extedded use PCRE2_SUBSTITUTE_EXTENDED 1218 substitute_overflow_length use PCRE2_SUBSTITUTE_OVERFLOW_LENGTH 1219 substitute_unknown_unset use PCRE2_SUBSTITUTE_UNKNOWN_UNSET 1220 substitute_unset_empty use PCRE2_SUBSTITUTE_UNSET_EMPTY 1221 zero_terminate pass the subject as zero-terminated 1222</pre> 1223The effects of these modifiers are described in the following sections. When 1224matching via the POSIX wrapper API, the <b>aftertext</b>, <b>allaftertext</b>, 1225and <b>ovector</b> subject modifiers work as described below. All other 1226modifiers are either ignored, with a warning message, or cause an error. 1227</P> 1228<br><b> 1229Showing more text 1230</b><br> 1231<P> 1232The <b>aftertext</b> modifier requests that as well as outputting the part of 1233the subject string that matched the entire pattern, <b>pcre2test</b> should in 1234addition output the remainder of the subject string. This is useful for tests 1235where the subject contains multiple copies of the same substring. The 1236<b>allaftertext</b> modifier requests the same action for captured substrings as 1237well as the main matched substring. In each case the remainder is output on the 1238following line with a plus character following the capture number. 1239</P> 1240<P> 1241The <b>allusedtext</b> modifier requests that all the text that was consulted 1242during a successful pattern match by the interpreter should be shown. This 1243feature is not supported for JIT matching, and if requested with JIT it is 1244ignored (with a warning message). Setting this modifier affects the output if 1245there is a lookbehind at the start of a match, or a lookahead at the end, or if 1246\K is used in the pattern. Characters that precede or follow the start and end 1247of the actual match are indicated in the output by '<' or '>' characters 1248underneath them. Here is an example: 1249<pre> 1250 re> /(?<=pqr)abc(?=xyz)/ 1251 data> 123pqrabcxyz456\=allusedtext 1252 0: pqrabcxyz 1253 <<< >>> 1254</pre> 1255This shows that the matched string is "abc", with the preceding and following 1256strings "pqr" and "xyz" having been consulted during the match (when processing 1257the assertions). 1258</P> 1259<P> 1260The <b>startchar</b> modifier requests that the starting character for the match 1261be indicated, if it is different to the start of the matched string. The only 1262time when this occurs is when \K has been processed as part of the match. In 1263this situation, the output for the matched string is displayed from the 1264starting character instead of from the match point, with circumflex characters 1265under the earlier characters. For example: 1266<pre> 1267 re> /abc\Kxyz/ 1268 data> abcxyz\=startchar 1269 0: abcxyz 1270 ^^^ 1271</pre> 1272Unlike <b>allusedtext</b>, the <b>startchar</b> modifier can be used with JIT. 1273However, these two modifiers are mutually exclusive. 1274</P> 1275<br><b> 1276Showing the value of all capture groups 1277</b><br> 1278<P> 1279The <b>allcaptures</b> modifier requests that the values of all potential 1280captured parentheses be output after a match. By default, only those up to the 1281highest one actually used in the match are output (corresponding to the return 1282code from <b>pcre2_match()</b>). Groups that did not take part in the match 1283are output as "<unset>". This modifier is not relevant for DFA matching (which 1284does no capturing); it is ignored, with a warning message, if present. 1285</P> 1286<br><b> 1287Testing callouts 1288</b><br> 1289<P> 1290A callout function is supplied when <b>pcre2test</b> calls the library matching 1291functions, unless <b>callout_none</b> is specified. Its behaviour can be 1292controlled by various modifiers listed above whose names begin with 1293<b>callout_</b>. Details are given in the section entitled "Callouts" 1294<a href="#callouts">below.</a> 1295</P> 1296<br><b> 1297Finding all matches in a string 1298</b><br> 1299<P> 1300Searching for all possible matches within a subject can be requested by the 1301<b>global</b> or <b>altglobal</b> modifier. After finding a match, the matching 1302function is called again to search the remainder of the subject. The difference 1303between <b>global</b> and <b>altglobal</b> is that the former uses the 1304<i>start_offset</i> argument to <b>pcre2_match()</b> or <b>pcre2_dfa_match()</b> 1305to start searching at a new point within the entire string (which is what Perl 1306does), whereas the latter passes over a shortened subject. This makes a 1307difference to the matching process if the pattern begins with a lookbehind 1308assertion (including \b or \B). 1309</P> 1310<P> 1311If an empty string is matched, the next match is done with the 1312PCRE2_NOTEMPTY_ATSTART and PCRE2_ANCHORED flags set, in order to search for 1313another, non-empty, match at the same point in the subject. If this match 1314fails, the start offset is advanced, and the normal match is retried. This 1315imitates the way Perl handles such cases when using the <b>/g</b> modifier or 1316the <b>split()</b> function. Normally, the start offset is advanced by one 1317character, but if the newline convention recognizes CRLF as a newline, and the 1318current character is CR followed by LF, an advance of two characters occurs. 1319</P> 1320<br><b> 1321Testing substring extraction functions 1322</b><br> 1323<P> 1324The <b>copy</b> and <b>get</b> modifiers can be used to test the 1325<b>pcre2_substring_copy_xxx()</b> and <b>pcre2_substring_get_xxx()</b> functions. 1326They can be given more than once, and each can specify a group name or number, 1327for example: 1328<pre> 1329 abcd\=copy=1,copy=3,get=G1 1330</pre> 1331If the <b>#subject</b> command is used to set default copy and/or get lists, 1332these can be unset by specifying a negative number to cancel all numbered 1333groups and an empty name to cancel all named groups. 1334</P> 1335<P> 1336The <b>getall</b> modifier tests <b>pcre2_substring_list_get()</b>, which 1337extracts all captured substrings. 1338</P> 1339<P> 1340If the subject line is successfully matched, the substrings extracted by the 1341convenience functions are output with C, G, or L after the string number 1342instead of a colon. This is in addition to the normal full list. The string 1343length (that is, the return from the extraction function) is given in 1344parentheses after each substring, followed by the name when the extraction was 1345by name. 1346</P> 1347<br><b> 1348Testing the substitution function 1349</b><br> 1350<P> 1351If the <b>replace</b> modifier is set, the <b>pcre2_substitute()</b> function is 1352called instead of one of the matching functions. Note that replacement strings 1353cannot contain commas, because a comma signifies the end of a modifier. This is 1354not thought to be an issue in a test program. 1355</P> 1356<P> 1357Unlike subject strings, <b>pcre2test</b> does not process replacement strings 1358for escape sequences. In UTF mode, a replacement string is checked to see if it 1359is a valid UTF-8 string. If so, it is correctly converted to a UTF string of 1360the appropriate code unit width. If it is not a valid UTF-8 string, the 1361individual code units are copied directly. This provides a means of passing an 1362invalid UTF-8 string for testing purposes. 1363</P> 1364<P> 1365The following modifiers set options (in additional to the normal match options) 1366for <b>pcre2_substitute()</b>: 1367<pre> 1368 global PCRE2_SUBSTITUTE_GLOBAL 1369 substitute_extended PCRE2_SUBSTITUTE_EXTENDED 1370 substitute_overflow_length PCRE2_SUBSTITUTE_OVERFLOW_LENGTH 1371 substitute_unknown_unset PCRE2_SUBSTITUTE_UNKNOWN_UNSET 1372 substitute_unset_empty PCRE2_SUBSTITUTE_UNSET_EMPTY 1373 1374</PRE> 1375</P> 1376<P> 1377After a successful substitution, the modified string is output, preceded by the 1378number of replacements. This may be zero if there were no matches. Here is a 1379simple example of a substitution test: 1380<pre> 1381 /abc/replace=xxx 1382 =abc=abc= 1383 1: =xxx=abc= 1384 =abc=abc=\=global 1385 2: =xxx=xxx= 1386</pre> 1387Subject and replacement strings should be kept relatively short (fewer than 256 1388characters) for substitution tests, as fixed-size buffers are used. To make it 1389easy to test for buffer overflow, if the replacement string starts with a 1390number in square brackets, that number is passed to <b>pcre2_substitute()</b> as 1391the size of the output buffer, with the replacement string starting at the next 1392character. Here is an example that tests the edge case: 1393<pre> 1394 /abc/ 1395 123abc123\=replace=[10]XYZ 1396 1: 123XYZ123 1397 123abc123\=replace=[9]XYZ 1398 Failed: error -47: no more memory 1399</pre> 1400The default action of <b>pcre2_substitute()</b> is to return 1401PCRE2_ERROR_NOMEMORY when the output buffer is too small. However, if the 1402PCRE2_SUBSTITUTE_OVERFLOW_LENGTH option is set (by using the 1403<b>substitute_overflow_length</b> modifier), <b>pcre2_substitute()</b> continues 1404to go through the motions of matching and substituting, in order to compute the 1405size of buffer that is required. When this happens, <b>pcre2test</b> shows the 1406required buffer length (which includes space for the trailing zero) as part of 1407the error message. For example: 1408<pre> 1409 /abc/substitute_overflow_length 1410 123abc123\=replace=[9]XYZ 1411 Failed: error -47: no more memory: 10 code units are needed 1412</pre> 1413A replacement string is ignored with POSIX and DFA matching. Specifying partial 1414matching provokes an error return ("bad option value") from 1415<b>pcre2_substitute()</b>. 1416</P> 1417<br><b> 1418Setting the JIT stack size 1419</b><br> 1420<P> 1421The <b>jitstack</b> modifier provides a way of setting the maximum stack size 1422that is used by the just-in-time optimization code. It is ignored if JIT 1423optimization is not being used. The value is a number of kibibytes (units of 14241024 bytes). Setting zero reverts to the default of 32KiB. Providing a stack 1425that is larger than the default is necessary only for very complicated 1426patterns. If <b>jitstack</b> is set non-zero on a subject line it overrides any 1427value that was set on the pattern. 1428</P> 1429<br><b> 1430Setting heap, match, and depth limits 1431</b><br> 1432<P> 1433The <b>heap_limit</b>, <b>match_limit</b>, and <b>depth_limit</b> modifiers set 1434the appropriate limits in the match context. These values are ignored when the 1435<b>find_limits</b> modifier is specified. 1436</P> 1437<br><b> 1438Finding minimum limits 1439</b><br> 1440<P> 1441If the <b>find_limits</b> modifier is present on a subject line, <b>pcre2test</b> 1442calls the relevant matching function several times, setting different values in 1443the match context via <b>pcre2_set_heap_limit()</b>, 1444<b>pcre2_set_match_limit()</b>, or <b>pcre2_set_depth_limit()</b> until it finds 1445the minimum values for each parameter that allows the match to complete without 1446error. If JIT is being used, only the match limit is relevant. 1447</P> 1448<P> 1449When using this modifier, the pattern should not contain any limit settings 1450such as (*LIMIT_MATCH=...) within it. If such a setting is present and is 1451lower than the minimum matching value, the minimum value cannot be found 1452because <b>pcre2_set_match_limit()</b> etc. are only able to reduce the value of 1453an in-pattern limit; they cannot increase it. 1454</P> 1455<P> 1456For non-DFA matching, the minimum <i>depth_limit</i> number is a measure of how 1457much nested backtracking happens (that is, how deeply the pattern's tree is 1458searched). In the case of DFA matching, <i>depth_limit</i> controls the depth of 1459recursive calls of the internal function that is used for handling pattern 1460recursion, lookaround assertions, and atomic groups. 1461</P> 1462<P> 1463For non-DFA matching, the <i>match_limit</i> number is a measure of the amount 1464of backtracking that takes place, and learning the minimum value can be 1465instructive. For most simple matches, the number is quite small, but for 1466patterns with very large numbers of matching possibilities, it can become large 1467very quickly with increasing length of subject string. In the case of DFA 1468matching, <i>match_limit</i> controls the total number of calls, both recursive 1469and non-recursive, to the internal matching function, thus controlling the 1470overall amount of computing resource that is used. 1471</P> 1472<P> 1473For both kinds of matching, the <i>heap_limit</i> number, which is in kibibytes 1474(units of 1024 bytes), limits the amount of heap memory used for matching. A 1475value of zero disables the use of any heap memory; many simple pattern matches 1476can be done without using the heap, so zero is not an unreasonable setting. 1477</P> 1478<br><b> 1479Showing MARK names 1480</b><br> 1481<P> 1482The <b>mark</b> modifier causes the names from backtracking control verbs that 1483are returned from calls to <b>pcre2_match()</b> to be displayed. If a mark is 1484returned for a match, non-match, or partial match, <b>pcre2test</b> shows it. 1485For a match, it is on a line by itself, tagged with "MK:". Otherwise, it 1486is added to the non-match message. 1487</P> 1488<br><b> 1489Showing memory usage 1490</b><br> 1491<P> 1492The <b>memory</b> modifier causes <b>pcre2test</b> to log the sizes of all heap 1493memory allocation and freeing calls that occur during a call to 1494<b>pcre2_match()</b> or <b>pcre2_dfa_match()</b>. These occur only when a match 1495requires a bigger vector than the default for remembering backtracking points 1496(<b>pcre2_match()</b>) or for internal workspace (<b>pcre2_dfa_match()</b>). In 1497many cases there will be no heap memory used and therefore no additional 1498output. No heap memory is allocated during matching with JIT, so in that case 1499the <b>memory</b> modifier never has any effect. For this modifier to work, the 1500<b>null_context</b> modifier must not be set on both the pattern and the 1501subject, though it can be set on one or the other. 1502</P> 1503<br><b> 1504Setting a starting offset 1505</b><br> 1506<P> 1507The <b>offset</b> modifier sets an offset in the subject string at which 1508matching starts. Its value is a number of code units, not characters. 1509</P> 1510<br><b> 1511Setting an offset limit 1512</b><br> 1513<P> 1514The <b>offset_limit</b> modifier sets a limit for unanchored matches. If a match 1515cannot be found starting at or before this offset in the subject, a "no match" 1516return is given. The data value is a number of code units, not characters. When 1517this modifier is used, the <b>use_offset_limit</b> modifier must have been set 1518for the pattern; if not, an error is generated. 1519</P> 1520<br><b> 1521Setting the size of the output vector 1522</b><br> 1523<P> 1524The <b>ovector</b> modifier applies only to the subject line in which it 1525appears, though of course it can also be used to set a default in a 1526<b>#subject</b> command. It specifies the number of pairs of offsets that are 1527available for storing matching information. The default is 15. 1528</P> 1529<P> 1530A value of zero is useful when testing the POSIX API because it causes 1531<b>regexec()</b> to be called with a NULL capture vector. When not testing the 1532POSIX API, a value of zero is used to cause 1533<b>pcre2_match_data_create_from_pattern()</b> to be called, in order to create a 1534match block of exactly the right size for the pattern. (It is not possible to 1535create a match block with a zero-length ovector; there is always at least one 1536pair of offsets.) 1537</P> 1538<br><b> 1539Passing the subject as zero-terminated 1540</b><br> 1541<P> 1542By default, the subject string is passed to a native API matching function with 1543its correct length. In order to test the facility for passing a zero-terminated 1544string, the <b>zero_terminate</b> modifier is provided. It causes the length to 1545be passed as PCRE2_ZERO_TERMINATED. When matching via the POSIX interface, 1546this modifier is ignored, with a warning. 1547</P> 1548<P> 1549When testing <b>pcre2_substitute()</b>, this modifier also has the effect of 1550passing the replacement string as zero-terminated. 1551</P> 1552<br><b> 1553Passing a NULL context 1554</b><br> 1555<P> 1556Normally, <b>pcre2test</b> passes a context block to <b>pcre2_match()</b>, 1557<b>pcre2_dfa_match()</b> or <b>pcre2_jit_match()</b>. If the <b>null_context</b> 1558modifier is set, however, NULL is passed. This is for testing that the matching 1559functions behave correctly in this case (they use default values). This 1560modifier cannot be used with the <b>find_limits</b> modifier or when testing the 1561substitution function. 1562</P> 1563<br><a name="SEC12" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br> 1564<P> 1565By default, <b>pcre2test</b> uses the standard PCRE2 matching function, 1566<b>pcre2_match()</b> to match each subject line. PCRE2 also supports an 1567alternative matching function, <b>pcre2_dfa_match()</b>, which operates in a 1568different way, and has some restrictions. The differences between the two 1569functions are described in the 1570<a href="pcre2matching.html"><b>pcre2matching</b></a> 1571documentation. 1572</P> 1573<P> 1574If the <b>dfa</b> modifier is set, the alternative matching function is used. 1575This function finds all possible matches at a given point in the subject. If, 1576however, the <b>dfa_shortest</b> modifier is set, processing stops after the 1577first match is found. This is always the shortest possible match. 1578</P> 1579<br><a name="SEC13" href="#TOC1">DEFAULT OUTPUT FROM pcre2test</a><br> 1580<P> 1581This section describes the output when the normal matching function, 1582<b>pcre2_match()</b>, is being used. 1583</P> 1584<P> 1585When a match succeeds, <b>pcre2test</b> outputs the list of captured substrings, 1586starting with number 0 for the string that matched the whole pattern. 1587Otherwise, it outputs "No match" when the return is PCRE2_ERROR_NOMATCH, or 1588"Partial match:" followed by the partially matching substring when the 1589return is PCRE2_ERROR_PARTIAL. (Note that this is the 1590entire substring that was inspected during the partial match; it may include 1591characters before the actual match start if a lookbehind assertion, \K, \b, 1592or \B was involved.) 1593</P> 1594<P> 1595For any other return, <b>pcre2test</b> outputs the PCRE2 negative error number 1596and a short descriptive phrase. If the error is a failed UTF string check, the 1597code unit offset of the start of the failing character is also output. Here is 1598an example of an interactive <b>pcre2test</b> run. 1599<pre> 1600 $ pcre2test 1601 PCRE2 version 10.22 2016-07-29 1602 1603 re> /^abc(\d+)/ 1604 data> abc123 1605 0: abc123 1606 1: 123 1607 data> xyz 1608 No match 1609</pre> 1610Unset capturing substrings that are not followed by one that is set are not 1611shown by <b>pcre2test</b> unless the <b>allcaptures</b> modifier is specified. In 1612the following example, there are two capturing substrings, but when the first 1613data line is matched, the second, unset substring is not shown. An "internal" 1614unset substring is shown as "<unset>", as for the second data line. 1615<pre> 1616 re> /(a)|(b)/ 1617 data> a 1618 0: a 1619 1: a 1620 data> b 1621 0: b 1622 1: <unset> 1623 2: b 1624</pre> 1625If the strings contain any non-printing characters, they are output as \xhh 1626escapes if the value is less than 256 and UTF mode is not set. Otherwise they 1627are output as \x{hh...} escapes. See below for the definition of non-printing 1628characters. If the <b>aftertext</b> modifier is set, the output for substring 16290 is followed by the the rest of the subject string, identified by "0+" like 1630this: 1631<pre> 1632 re> /cat/aftertext 1633 data> cataract 1634 0: cat 1635 0+ aract 1636</pre> 1637If global matching is requested, the results of successive matching attempts 1638are output in sequence, like this: 1639<pre> 1640 re> /\Bi(\w\w)/g 1641 data> Mississippi 1642 0: iss 1643 1: ss 1644 0: iss 1645 1: ss 1646 0: ipp 1647 1: pp 1648</pre> 1649"No match" is output only if the first match attempt fails. Here is an example 1650of a failure message (the offset 4 that is specified by the <b>offset</b> 1651modifier is past the end of the subject string): 1652<pre> 1653 re> /xyz/ 1654 data> xyz\=offset=4 1655 Error -24 (bad offset value) 1656</PRE> 1657</P> 1658<P> 1659Note that whereas patterns can be continued over several lines (a plain ">" 1660prompt is used for continuations), subject lines may not. However newlines can 1661be included in a subject by means of the \n escape (or \r, \r\n, etc., 1662depending on the newline sequence setting). 1663</P> 1664<br><a name="SEC14" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br> 1665<P> 1666When the alternative matching function, <b>pcre2_dfa_match()</b>, is used, the 1667output consists of a list of all the matches that start at the first point in 1668the subject where there is at least one match. For example: 1669<pre> 1670 re> /(tang|tangerine|tan)/ 1671 data> yellow tangerine\=dfa 1672 0: tangerine 1673 1: tang 1674 2: tan 1675</pre> 1676Using the normal matching function on this data finds only "tang". The 1677longest matching string is always given first (and numbered zero). After a 1678PCRE2_ERROR_PARTIAL return, the output is "Partial match:", followed by the 1679partially matching substring. Note that this is the entire substring that was 1680inspected during the partial match; it may include characters before the actual 1681match start if a lookbehind assertion, \b, or \B was involved. (\K is not 1682supported for DFA matching.) 1683</P> 1684<P> 1685If global matching is requested, the search for further matches resumes 1686at the end of the longest match. For example: 1687<pre> 1688 re> /(tang|tangerine|tan)/g 1689 data> yellow tangerine and tangy sultana\=dfa 1690 0: tangerine 1691 1: tang 1692 2: tan 1693 0: tang 1694 1: tan 1695 0: tan 1696</pre> 1697The alternative matching function does not support substring capture, so the 1698modifiers that are concerned with captured substrings are not relevant. 1699</P> 1700<br><a name="SEC15" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br> 1701<P> 1702When the alternative matching function has given the PCRE2_ERROR_PARTIAL 1703return, indicating that the subject partially matched the pattern, you can 1704restart the match with additional subject data by means of the 1705<b>dfa_restart</b> modifier. For example: 1706<pre> 1707 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ 1708 data> 23ja\=P,dfa 1709 Partial match: 23ja 1710 data> n05\=dfa,dfa_restart 1711 0: n05 1712</pre> 1713For further information about partial matching, see the 1714<a href="pcre2partial.html"><b>pcre2partial</b></a> 1715documentation. 1716<a name="callouts"></a></P> 1717<br><a name="SEC16" href="#TOC1">CALLOUTS</a><br> 1718<P> 1719If the pattern contains any callout requests, <b>pcre2test</b>'s callout 1720function is called during matching unless <b>callout_none</b> is specified. This 1721works with both matching functions, and with JIT, though there are some 1722differences in behaviour. The output for callouts with numerical arguments and 1723those with string arguments is slightly different. 1724</P> 1725<br><b> 1726Callouts with numerical arguments 1727</b><br> 1728<P> 1729By default, the callout function displays the callout number, the start and 1730current positions in the subject text at the callout time, and the next pattern 1731item to be tested. For example: 1732<pre> 1733 --->pqrabcdef 1734 0 ^ ^ \d 1735</pre> 1736This output indicates that callout number 0 occurred for a match attempt 1737starting at the fourth character of the subject string, when the pointer was at 1738the seventh character, and when the next pattern item was \d. Just 1739one circumflex is output if the start and current positions are the same, or if 1740the current position precedes the start position, which can happen if the 1741callout is in a lookbehind assertion. 1742</P> 1743<P> 1744Callouts numbered 255 are assumed to be automatic callouts, inserted as a 1745result of the <b>auto_callout</b> pattern modifier. In this case, instead of 1746showing the callout number, the offset in the pattern, preceded by a plus, is 1747output. For example: 1748<pre> 1749 re> /\d?[A-E]\*/auto_callout 1750 data> E* 1751 --->E* 1752 +0 ^ \d? 1753 +3 ^ [A-E] 1754 +8 ^^ \* 1755 +10 ^ ^ 1756 0: E* 1757</pre> 1758If a pattern contains (*MARK) items, an additional line is output whenever 1759a change of latest mark is passed to the callout function. For example: 1760<pre> 1761 re> /a(*MARK:X)bc/auto_callout 1762 data> abc 1763 --->abc 1764 +0 ^ a 1765 +1 ^^ (*MARK:X) 1766 +10 ^^ b 1767 Latest Mark: X 1768 +11 ^ ^ c 1769 +12 ^ ^ 1770 0: abc 1771</pre> 1772The mark changes between matching "a" and "b", but stays the same for the rest 1773of the match, so nothing more is output. If, as a result of backtracking, the 1774mark reverts to being unset, the text "<unset>" is output. 1775</P> 1776<br><b> 1777Callouts with string arguments 1778</b><br> 1779<P> 1780The output for a callout with a string argument is similar, except that instead 1781of outputting a callout number before the position indicators, the callout 1782string and its offset in the pattern string are output before the reflection of 1783the subject string, and the subject string is reflected for each callout. For 1784example: 1785<pre> 1786 re> /^ab(?C'first')cd(?C"second")ef/ 1787 data> abcdefg 1788 Callout (7): 'first' 1789 --->abcdefg 1790 ^ ^ c 1791 Callout (20): "second" 1792 --->abcdefg 1793 ^ ^ e 1794 0: abcdef 1795 1796</PRE> 1797</P> 1798<br><b> 1799Callout modifiers 1800</b><br> 1801<P> 1802The callout function in <b>pcre2test</b> returns zero (carry on matching) by 1803default, but you can use a <b>callout_fail</b> modifier in a subject line to 1804change this and other parameters of the callout (see below). 1805</P> 1806<P> 1807If the <b>callout_capture</b> modifier is set, the current captured groups are 1808output when a callout occurs. This is useful only for non-DFA matching, as 1809<b>pcre2_dfa_match()</b> does not support capturing, so no captures are ever 1810shown. 1811</P> 1812<P> 1813The normal callout output, showing the callout number or pattern offset (as 1814described above) is suppressed if the <b>callout_no_where</b> modifier is set. 1815</P> 1816<P> 1817When using the interpretive matching function <b>pcre2_match()</b> without JIT, 1818setting the <b>callout_extra</b> modifier causes additional output from 1819<b>pcre2test</b>'s callout function to be generated. For the first callout in a 1820match attempt at a new starting position in the subject, "New match attempt" is 1821output. If there has been a backtrack since the last callout (or start of 1822matching if this is the first callout), "Backtrack" is output, followed by "No 1823other matching paths" if the backtrack ended the previous match attempt. For 1824example: 1825<pre> 1826 re> /(a+)b/auto_callout,no_start_optimize,no_auto_possess 1827 data> aac\=callout_extra 1828 New match attempt 1829 --->aac 1830 +0 ^ ( 1831 +1 ^ a+ 1832 +3 ^ ^ ) 1833 +4 ^ ^ b 1834 Backtrack 1835 --->aac 1836 +3 ^^ ) 1837 +4 ^^ b 1838 Backtrack 1839 No other matching paths 1840 New match attempt 1841 --->aac 1842 +0 ^ ( 1843 +1 ^ a+ 1844 +3 ^^ ) 1845 +4 ^^ b 1846 Backtrack 1847 No other matching paths 1848 New match attempt 1849 --->aac 1850 +0 ^ ( 1851 +1 ^ a+ 1852 Backtrack 1853 No other matching paths 1854 New match attempt 1855 --->aac 1856 +0 ^ ( 1857 +1 ^ a+ 1858 No match 1859</pre> 1860Notice that various optimizations must be turned off if you want all possible 1861matching paths to be scanned. If <b>no_start_optimize</b> is not used, there is 1862an immediate "no match", without any callouts, because the starting 1863optimization fails to find "b" in the subject, which it knows must be present 1864for any match. If <b>no_auto_possess</b> is not used, the "a+" item is turned 1865into "a++", which reduces the number of backtracks. 1866</P> 1867<P> 1868The <b>callout_extra</b> modifier has no effect if used with the DFA matching 1869function, or with JIT. 1870</P> 1871<br><b> 1872Return values from callouts 1873</b><br> 1874<P> 1875The default return from the callout function is zero, which allows matching to 1876continue. The <b>callout_fail</b> modifier can be given one or two numbers. If 1877there is only one number, 1 is returned instead of 0 (causing matching to 1878backtrack) when a callout of that number is reached. If two numbers (<n>:<m>) 1879are given, 1 is returned when callout <n> is reached and there have been at 1880least <m> callouts. The <b>callout_error</b> modifier is similar, except that 1881PCRE2_ERROR_CALLOUT is returned, causing the entire matching process to be 1882aborted. If both these modifiers are set for the same callout number, 1883<b>callout_error</b> takes precedence. Note that callouts with string arguments 1884are always given the number zero. 1885</P> 1886<P> 1887The <b>callout_data</b> modifier can be given an unsigned or a negative number. 1888This is set as the "user data" that is passed to the matching function, and 1889passed back when the callout function is invoked. Any value other than zero is 1890used as a return from <b>pcre2test</b>'s callout function. 1891</P> 1892<P> 1893Inserting callouts can be helpful when using <b>pcre2test</b> to check 1894complicated regular expressions. For further information about callouts, see 1895the 1896<a href="pcre2callout.html"><b>pcre2callout</b></a> 1897documentation. 1898</P> 1899<br><a name="SEC17" href="#TOC1">NON-PRINTING CHARACTERS</a><br> 1900<P> 1901When <b>pcre2test</b> is outputting text in the compiled version of a pattern, 1902bytes other than 32-126 are always treated as non-printing characters and are 1903therefore shown as hex escapes. 1904</P> 1905<P> 1906When <b>pcre2test</b> is outputting text that is a matched part of a subject 1907string, it behaves in the same way, unless a different locale has been set for 1908the pattern (using the <b>locale</b> modifier). In this case, the 1909<b>isprint()</b> function is used to distinguish printing and non-printing 1910characters. 1911<a name="saverestore"></a></P> 1912<br><a name="SEC18" href="#TOC1">SAVING AND RESTORING COMPILED PATTERNS</a><br> 1913<P> 1914It is possible to save compiled patterns on disc or elsewhere, and reload them 1915later, subject to a number of restrictions. JIT data cannot be saved. The host 1916on which the patterns are reloaded must be running the same version of PCRE2, 1917with the same code unit width, and must also have the same endianness, pointer 1918width and PCRE2_SIZE type. Before compiled patterns can be saved they must be 1919serialized, that is, converted to a stream of bytes. A single byte stream may 1920contain any number of compiled patterns, but they must all use the same 1921character tables. A single copy of the tables is included in the byte stream 1922(its size is 1088 bytes). 1923</P> 1924<P> 1925The functions whose names begin with <b>pcre2_serialize_</b> are used 1926for serializing and de-serializing. They are described in the 1927<a href="pcre2serialize.html"><b>pcre2serialize</b></a> 1928documentation. In this section we describe the features of <b>pcre2test</b> that 1929can be used to test these functions. 1930</P> 1931<P> 1932Note that "serialization" in PCRE2 does not convert compiled patterns to an 1933abstract format like Java or .NET. It just makes a reloadable byte code stream. 1934Hence the restrictions on reloading mentioned above. 1935</P> 1936<P> 1937In <b>pcre2test</b>, when a pattern with <b>push</b> modifier is successfully 1938compiled, it is pushed onto a stack of compiled patterns, and <b>pcre2test</b> 1939expects the next line to contain a new pattern (or command) instead of a 1940subject line. By contrast, the <b>pushcopy</b> modifier causes a copy of the 1941compiled pattern to be stacked, leaving the original available for immediate 1942matching. By using <b>push</b> and/or <b>pushcopy</b>, a number of patterns can 1943be compiled and retained. These modifiers are incompatible with <b>posix</b>, 1944and control modifiers that act at match time are ignored (with a message) for 1945the stacked patterns. The <b>jitverify</b> modifier applies only at compile 1946time. 1947</P> 1948<P> 1949The command 1950<pre> 1951 #save <filename> 1952</pre> 1953causes all the stacked patterns to be serialized and the result written to the 1954named file. Afterwards, all the stacked patterns are freed. The command 1955<pre> 1956 #load <filename> 1957</pre> 1958reads the data in the file, and then arranges for it to be de-serialized, with 1959the resulting compiled patterns added to the pattern stack. The pattern on the 1960top of the stack can be retrieved by the #pop command, which must be followed 1961by lines of subjects that are to be matched with the pattern, terminated as 1962usual by an empty line or end of file. This command may be followed by a 1963modifier list containing only 1964<a href="#controlmodifiers">control modifiers</a> 1965that act after a pattern has been compiled. In particular, <b>hex</b>, 1966<b>posix</b>, <b>posix_nosub</b>, <b>push</b>, and <b>pushcopy</b> are not allowed, 1967nor are any 1968<a href="#optionmodifiers">option-setting modifiers.</a> 1969The JIT modifiers are, however permitted. Here is an example that saves and 1970reloads two patterns. 1971<pre> 1972 /abc/push 1973 /xyz/push 1974 #save tempfile 1975 #load tempfile 1976 #pop info 1977 xyz 1978 1979 #pop jit,bincode 1980 abc 1981</pre> 1982If <b>jitverify</b> is used with #pop, it does not automatically imply 1983<b>jit</b>, which is different behaviour from when it is used on a pattern. 1984</P> 1985<P> 1986The #popcopy command is analagous to the <b>pushcopy</b> modifier in that it 1987makes current a copy of the topmost stack pattern, leaving the original still 1988on the stack. 1989</P> 1990<br><a name="SEC19" href="#TOC1">SEE ALSO</a><br> 1991<P> 1992<b>pcre2</b>(3), <b>pcre2api</b>(3), <b>pcre2callout</b>(3), 1993<b>pcre2jit</b>, <b>pcre2matching</b>(3), <b>pcre2partial</b>(d), 1994<b>pcre2pattern</b>(3), <b>pcre2serialize</b>(3). 1995</P> 1996<br><a name="SEC20" href="#TOC1">AUTHOR</a><br> 1997<P> 1998Philip Hazel 1999<br> 2000University Computing Service 2001<br> 2002Cambridge, England. 2003<br> 2004</P> 2005<br><a name="SEC21" href="#TOC1">REVISION</a><br> 2006<P> 2007Last updated: 21 July 2018 2008<br> 2009Copyright © 1997-2018 University of Cambridge. 2010<br> 2011<p> 2012Return to the <a href="index.html">PCRE2 index page</a>. 2013</p> 2014