"Fossies" - the Fresh Open Source Software Archive

Member "pcre-8.44/doc/html/pcretest.html" (12 Feb 2020, 51994 Bytes) of package /linux/misc/pcre-8.44.tar.bz2:

As a special service "Fossies" has tried to format the requested source page into HTML format using (guessed) HTML source code syntax highlighting (style: standard) with prefixed line numbers. Alternatively you can here view or download the uninterpreted source code file.

    1 <html>
    2 <head>
    3 <title>pcretest specification</title>
    4 </head>
    5 <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
    6 <h1>pcretest man page</h1>
    7 <p>
    8 Return to the <a href="index.html">PCRE index page</a>.
    9 </p>
   10 <p>
   11 This page is part of the PCRE HTML documentation. It was generated automatically
   12 from the original man page. If there is any nonsense in it, please consult the
   13 man page, in case the conversion went wrong.
   14 <br>
   15 <ul>
   16 <li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
   17 <li><a name="TOC2" href="#SEC2">INPUT DATA FORMAT</a>
   18 <li><a name="TOC3" href="#SEC3">PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES</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">PATTERN MODIFIERS</a>
   22 <li><a name="TOC7" href="#SEC7">DATA LINES</a>
   23 <li><a name="TOC8" href="#SEC8">THE ALTERNATIVE MATCHING FUNCTION</a>
   24 <li><a name="TOC9" href="#SEC9">DEFAULT OUTPUT FROM PCRETEST</a>
   26 <li><a name="TOC11" href="#SEC11">RESTARTING AFTER A PARTIAL MATCH</a>
   27 <li><a name="TOC12" href="#SEC12">CALLOUTS</a>
   28 <li><a name="TOC13" href="#SEC13">NON-PRINTING CHARACTERS</a>
   29 <li><a name="TOC14" href="#SEC14">SAVING AND RELOADING COMPILED PATTERNS</a>
   30 <li><a name="TOC15" href="#SEC15">SEE ALSO</a>
   31 <li><a name="TOC16" href="#SEC16">AUTHOR</a>
   32 <li><a name="TOC17" href="#SEC17">REVISION</a>
   33 </ul>
   34 <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
   35 <P>
   36 <b>pcretest [options] [input file [output file]]</b>
   37 <br>
   38 <br>
   39 <b>pcretest</b> was written as a test program for the PCRE regular expression
   40 library itself, but it can also be used for experimenting with regular
   41 expressions. This document describes the features of the test program; for
   42 details of the regular expressions themselves, see the
   43 <a href="pcrepattern.html"><b>pcrepattern</b></a>
   44 documentation. For details of the PCRE library function calls and their
   45 options, see the
   46 <a href="pcreapi.html"><b>pcreapi</b></a>
   47 ,
   48 <a href="pcre16.html"><b>pcre16</b></a>
   49 and
   50 <a href="pcre32.html"><b>pcre32</b></a>
   51 documentation.
   52 </P>
   53 <P>
   54 The input for <b>pcretest</b> is a sequence of regular expression patterns and
   55 strings to be matched, as described below. The output shows the result of each
   56 match. Options on the command line and the patterns control PCRE options and
   57 exactly what is output.
   58 </P>
   59 <P>
   60 As PCRE has evolved, it has acquired many different features, and as a result,
   61 <b>pcretest</b> now has rather a lot of obscure options for testing every
   62 possible feature. Some of these options are specifically designed for use in
   63 conjunction with the test script and data files that are distributed as part of
   64 PCRE, and are unlikely to be of use otherwise. They are all documented here,
   65 but without much justification.
   66 </P>
   67 <br><a name="SEC2" href="#TOC1">INPUT DATA FORMAT</a><br>
   68 <P>
   69 Input to <b>pcretest</b> is processed line by line, either by calling the C
   70 library's <b>fgets()</b> function, or via the <b>libreadline</b> library (see
   71 below). In Unix-like environments, <b>fgets()</b> treats any bytes other than
   72 newline as data characters. However, in some Windows environments character 26
   73 (hex 1A) causes an immediate end of file, and no further data is read. For
   74 maximum portability, therefore, it is safest to use only ASCII characters in
   75 <b>pcretest</b> input files.
   76 </P>
   77 <P>
   78 The input is processed using using C's string functions, so must not
   79 contain binary zeroes, even though in Unix-like environments, <b>fgets()</b>
   80 treats any bytes other than newline as data characters.
   81 </P>
   82 <br><a name="SEC3" href="#TOC1">PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES</a><br>
   83 <P>
   84 From release 8.30, two separate PCRE libraries can be built. The original one
   85 supports 8-bit character strings, whereas the newer 16-bit library supports
   86 character strings encoded in 16-bit units. From release 8.32, a third library
   87 can be built, supporting character strings encoded in 32-bit units. The
   88 <b>pcretest</b> program can be used to test all three libraries. However, it is
   89 itself still an 8-bit program, reading 8-bit input and writing 8-bit output.
   90 When testing the 16-bit or 32-bit library, the patterns and data strings are
   91 converted to 16- or 32-bit format before being passed to the PCRE library
   92 functions. Results are converted to 8-bit for output.
   93 </P>
   94 <P>
   95 References to functions and structures of the form <b>pcre[16|32]_xx</b> below
   96 mean "<b>pcre_xx</b> when using the 8-bit library, <b>pcre16_xx</b> when using
   97 the 16-bit library, or <b>pcre32_xx</b> when using the 32-bit library".
   98 </P>
   99 <br><a name="SEC4" href="#TOC1">COMMAND LINE OPTIONS</a><br>
  100 <P>
  101 <b>-8</b>
  102 If the 8-bit library has been built, this option causes it to be used (this is
  103 the default). If the 8-bit library has not been built, this option causes an
  104 error.
  105 </P>
  106 <P>
  107 <b>-16</b>
  108 If the 16-bit library has been built, this option causes it to be used. If only
  109 the 16-bit library has been built, this is the default. If the 16-bit library
  110 has not been built, this option causes an error.
  111 </P>
  112 <P>
  113 <b>-32</b>
  114 If the 32-bit library has been built, this option causes it to be used. If only
  115 the 32-bit library has been built, this is the default. If the 32-bit library
  116 has not been built, this option causes an error.
  117 </P>
  118 <P>
  119 <b>-b</b>
  120 Behave as if each pattern has the <b>/B</b> (show byte code) modifier; the
  121 internal form is output after compilation.
  122 </P>
  123 <P>
  124 <b>-C</b>
  125 Output the version number of the PCRE library, and all available information
  126 about the optional features that are included, and then exit with zero exit
  127 code. All other options are ignored.
  128 </P>
  129 <P>
  130 <b>-C</b> <i>option</i>
  131 Output information about a specific build-time option, then exit. This
  132 functionality is intended for use in scripts such as <b>RunTest</b>. The
  133 following options output the value and set the exit code as indicated:
  134 <pre>
  135   ebcdic-nl  the code for LF (= NL) in an EBCDIC environment:
  136                0x15 or 0x25
  137                0 if used in an ASCII environment
  138                exit code is always 0
  139   linksize   the configured internal link size (2, 3, or 4)
  140                exit code is set to the link size
  141   newline    the default newline setting:
  142                CR, LF, CRLF, ANYCRLF, or ANY
  143                exit code is always 0
  144   bsr        the default setting for what \R matches:
  145                ANYCRLF or ANY
  146                exit code is always 0
  147 </pre>
  148 The following options output 1 for true or 0 for false, and set the exit code
  149 to the same value:
  150 <pre>
  151   ebcdic     compiled for an EBCDIC environment
  152   jit        just-in-time support is available
  153   pcre16     the 16-bit library was built
  154   pcre32     the 32-bit library was built
  155   pcre8      the 8-bit library was built
  156   ucp        Unicode property support is available
  157   utf        UTF-8 and/or UTF-16 and/or UTF-32 support
  158                is available
  159 </pre>
  160 If an unknown option is given, an error message is output; the exit code is 0.
  161 </P>
  162 <P>
  163 <b>-d</b>
  164 Behave as if each pattern has the <b>/D</b> (debug) modifier; the internal
  165 form and information about the compiled pattern is output after compilation;
  166 <b>-d</b> is equivalent to <b>-b -i</b>.
  167 </P>
  168 <P>
  169 <b>-dfa</b>
  170 Behave as if each data line contains the \D escape sequence; this causes the
  171 alternative matching function, <b>pcre[16|32]_dfa_exec()</b>, to be used instead
  172 of the standard <b>pcre[16|32]_exec()</b> function (more detail is given below).
  173 </P>
  174 <P>
  175 <b>-help</b>
  176 Output a brief summary these options and then exit.
  177 </P>
  178 <P>
  179 <b>-i</b>
  180 Behave as if each pattern has the <b>/I</b> modifier; information about the
  181 compiled pattern is given after compilation.
  182 </P>
  183 <P>
  184 <b>-M</b>
  185 Behave as if each data line contains the \M escape sequence; this causes
  186 PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by
  187 calling <b>pcre[16|32]_exec()</b> repeatedly with different limits.
  188 </P>
  189 <P>
  190 <b>-m</b>
  191 Output the size of each compiled pattern after it has been compiled. This is
  192 equivalent to adding <b>/M</b> to each regular expression. The size is given in
  193 bytes for both libraries.
  194 </P>
  195 <P>
  196 <b>-O</b>
  197 Behave as if each pattern has the <b>/O</b> modifier, that is disable
  198 auto-possessification for all patterns.
  199 </P>
  200 <P>
  201 <b>-o</b> <i>osize</i>
  202 Set the number of elements in the output vector that is used when calling
  203 <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> to be <i>osize</i>. The
  204 default value is 45, which is enough for 14 capturing subexpressions for
  205 <b>pcre[16|32]_exec()</b> or 22 different matches for
  206 <b>pcre[16|32]_dfa_exec()</b>.
  207 The vector size can be changed for individual matching calls by including \O
  208 in the data line (see below).
  209 </P>
  210 <P>
  211 <b>-p</b>
  212 Behave as if each pattern has the <b>/P</b> modifier; the POSIX wrapper API is
  213 used to call PCRE. None of the other options has any effect when <b>-p</b> is
  214 set. This option can be used only with the 8-bit library.
  215 </P>
  216 <P>
  217 <b>-q</b>
  218 Do not output the version number of <b>pcretest</b> at the start of execution.
  219 </P>
  220 <P>
  221 <b>-S</b> <i>size</i>
  222 On Unix-like systems, set the size of the run-time stack to <i>size</i>
  223 megabytes.
  224 </P>
  225 <P>
  226 <b>-s</b> or <b>-s+</b>
  227 Behave as if each pattern has the <b>/S</b> modifier; in other words, force each
  228 pattern to be studied. If <b>-s+</b> is used, all the JIT compile options are
  229 passed to <b>pcre[16|32]_study()</b>, causing just-in-time optimization to be set
  230 up if it is available, for both full and partial matching. Specific JIT compile
  231 options can be selected by following <b>-s+</b> with a digit in the range 1 to
  232 7, which selects the JIT compile modes as follows:
  233 <pre>
  234   1  normal match only
  235   2  soft partial match only
  236   3  normal match and soft partial match
  237   4  hard partial match only
  238   6  soft and hard partial match
  239   7  all three modes (default)
  240 </pre>
  241 If <b>-s++</b> is used instead of <b>-s+</b> (with or without a following digit),
  242 the text "(JIT)" is added to the first output line after a match or no match
  243 when JIT-compiled code was actually used.
  244 <br>
  245 <br>
  246 Note that there are pattern options that can override <b>-s</b>, either
  247 specifying no studying at all, or suppressing JIT compilation.
  248 <br>
  249 <br>
  250 If the <b>/I</b> or <b>/D</b> option is present on a pattern (requesting output
  251 about the compiled pattern), information about the result of studying is not
  252 included when studying is caused only by <b>-s</b> and neither <b>-i</b> nor
  253 <b>-d</b> is present on the command line. This behaviour means that the output
  254 from tests that are run with and without <b>-s</b> should be identical, except
  255 when options that output information about the actual running of a match are
  256 set.
  257 <br>
  258 <br>
  259 The <b>-M</b>, <b>-t</b>, and <b>-tm</b> options, which give information about
  260 resources used, are likely to produce different output with and without
  261 <b>-s</b>. Output may also differ if the <b>/C</b> option is present on an
  262 individual pattern. This uses callouts to trace the the matching process, and
  263 this may be different between studied and non-studied patterns. If the pattern
  264 contains (*MARK) items there may also be differences, for the same reason. The
  265 <b>-s</b> command line option can be overridden for specific patterns that
  266 should never be studied (see the <b>/S</b> pattern modifier below).
  267 </P>
  268 <P>
  269 <b>-t</b>
  270 Run each compile, study, and match many times with a timer, and output the
  271 resulting times per compile, study, or match (in milliseconds). Do not set
  272 <b>-m</b> with <b>-t</b>, because you will then get the size output a zillion
  273 times, and the timing will be distorted. You can control the number of
  274 iterations that are used for timing by following <b>-t</b> with a number (as a
  275 separate item on the command line). For example, "-t 1000" iterates 1000 times.
  276 The default is to iterate 500000 times.
  277 </P>
  278 <P>
  279 <b>-tm</b>
  280 This is like <b>-t</b> except that it times only the matching phase, not the
  281 compile or study phases.
  282 </P>
  283 <P>
  284 <b>-T</b> <b>-TM</b>
  285 These behave like <b>-t</b> and <b>-tm</b>, but in addition, at the end of a run,
  286 the total times for all compiles, studies, and matches are output.
  287 </P>
  288 <br><a name="SEC5" href="#TOC1">DESCRIPTION</a><br>
  289 <P>
  290 If <b>pcretest</b> is given two filename arguments, it reads from the first and
  291 writes to the second. If it is given only one filename argument, it reads from
  292 that file and writes to stdout. Otherwise, it reads from stdin and writes to
  293 stdout, and prompts for each line of input, using "re&#62;" to prompt for regular
  294 expressions, and "data&#62;" to prompt for data lines.
  295 </P>
  296 <P>
  297 When <b>pcretest</b> is built, a configuration option can specify that it should
  298 be linked with the <b>libreadline</b> library. When this is done, if the input
  299 is from a terminal, it is read using the <b>readline()</b> function. This
  300 provides line-editing and history facilities. The output from the <b>-help</b>
  301 option states whether or not <b>readline()</b> will be used.
  302 </P>
  303 <P>
  304 The program handles any number of sets of input on a single input file. Each
  305 set starts with a regular expression, and continues with any number of data
  306 lines to be matched against that pattern.
  307 </P>
  308 <P>
  309 Each data line is matched separately and independently. If you want to do
  310 multi-line matches, you have to use the \n escape sequence (or \r or \r\n,
  311 etc., depending on the newline setting) in a single line of input to encode the
  312 newline sequences. There is no limit on the length of data lines; the input
  313 buffer is automatically extended if it is too small.
  314 </P>
  315 <P>
  316 An empty line signals the end of the data lines, at which point a new regular
  317 expression is read. The regular expressions are given enclosed in any
  318 non-alphanumeric delimiters other than backslash, for example:
  319 <pre>
  320   /(a|bc)x+yz/
  321 </pre>
  322 White space before the initial delimiter is ignored. A regular expression may
  323 be continued over several input lines, in which case the newline characters are
  324 included within it. It is possible to include the delimiter within the pattern
  325 by escaping it, for example
  326 <pre>
  327   /abc\/def/
  328 </pre>
  329 If you do so, the escape and the delimiter form part of the pattern, but since
  330 delimiters are always non-alphanumeric, this does not affect its interpretation.
  331 If the terminating delimiter is immediately followed by a backslash, for
  332 example,
  333 <pre>
  334   /abc/\
  335 </pre>
  336 then a backslash is added to the end of the pattern. This is done to provide a
  337 way of testing the error condition that arises if a pattern finishes with a
  338 backslash, because
  339 <pre>
  340   /abc\/
  341 </pre>
  342 is interpreted as the first line of a pattern that starts with "abc/", causing
  343 pcretest to read the next line as a continuation of the regular expression.
  344 </P>
  345 <br><a name="SEC6" href="#TOC1">PATTERN MODIFIERS</a><br>
  346 <P>
  347 A pattern may be followed by any number of modifiers, which are mostly single
  348 characters, though some of these can be qualified by further characters.
  349 Following Perl usage, these are referred to below as, for example, "the
  350 <b>/i</b> modifier", even though the delimiter of the pattern need not always be
  351 a slash, and no slash is used when writing modifiers. White space may appear
  352 between the final pattern delimiter and the first modifier, and between the
  353 modifiers themselves. For reference, here is a complete list of modifiers. They
  354 fall into several groups that are described in detail in the following
  355 sections.
  356 <pre>
  357   <b>/8</b>              set UTF mode
  358   <b>/9</b>              set PCRE_NEVER_UTF (locks out UTF mode)
  359   <b>/?</b>              disable UTF validity check
  360   <b>/+</b>              show remainder of subject after match
  361   <b>/=</b>              show all captures (not just those that are set)
  363   <b>/A</b>              set PCRE_ANCHORED
  364   <b>/B</b>              show compiled code
  365   <b>/C</b>              set PCRE_AUTO_CALLOUT
  366   <b>/D</b>              same as <b>/B</b> plus <b>/I</b>
  367   <b>/E</b>              set PCRE_DOLLAR_ENDONLY
  368   <b>/F</b>              flip byte order in compiled pattern
  369   <b>/f</b>              set PCRE_FIRSTLINE
  370   <b>/G</b>              find all matches (shorten string)
  371   <b>/g</b>              find all matches (use startoffset)
  372   <b>/I</b>              show information about pattern
  373   <b>/i</b>              set PCRE_CASELESS
  374   <b>/J</b>              set PCRE_DUPNAMES
  375   <b>/K</b>              show backtracking control names
  376   <b>/L</b>              set locale
  377   <b>/M</b>              show compiled memory size
  378   <b>/m</b>              set PCRE_MULTILINE
  379   <b>/N</b>              set PCRE_NO_AUTO_CAPTURE
  380   <b>/O</b>              set PCRE_NO_AUTO_POSSESS
  381   <b>/P</b>              use the POSIX wrapper
  382   <b>/Q</b>              test external stack check function
  383   <b>/S</b>              study the pattern after compilation
  384   <b>/s</b>              set PCRE_DOTALL
  385   <b>/T</b>              select character tables
  386   <b>/U</b>              set PCRE_UNGREEDY
  387   <b>/W</b>              set PCRE_UCP
  388   <b>/X</b>              set PCRE_EXTRA
  389   <b>/x</b>              set PCRE_EXTENDED
  390   <b>/Y</b>              set PCRE_NO_START_OPTIMIZE
  391   <b>/Z</b>              don't show lengths in <b>/B</b> output
  393   <b>/&#60;any&#62;</b>          set PCRE_NEWLINE_ANY
  394   <b>/&#60;anycrlf&#62;</b>      set PCRE_NEWLINE_ANYCRLF
  395   <b>/&#60;cr&#62;</b>           set PCRE_NEWLINE_CR
  396   <b>/&#60;crlf&#62;</b>         set PCRE_NEWLINE_CRLF
  397   <b>/&#60;lf&#62;</b>           set PCRE_NEWLINE_LF
  398   <b>/&#60;bsr_anycrlf&#62;</b>  set PCRE_BSR_ANYCRLF
  399   <b>/&#60;bsr_unicode&#62;</b>  set PCRE_BSR_UNICODE
  400   <b>/&#60;JS&#62;</b>           set PCRE_JAVASCRIPT_COMPAT
  402 </PRE>
  403 </P>
  404 <br><b>
  405 Perl-compatible modifiers
  406 </b><br>
  407 <P>
  408 The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
  409 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
  410 <b>pcre[16|32]_compile()</b> is called. These four modifier letters have the same
  411 effect as they do in Perl. For example:
  412 <pre>
  413   /caseless/i
  415 </PRE>
  416 </P>
  417 <br><b>
  418 Modifiers for other PCRE options
  419 </b><br>
  420 <P>
  421 The following table shows additional modifiers for setting PCRE compile-time
  422 options that do not correspond to anything in Perl:
  423 <pre>
  424   <b>/8</b>              PCRE_UTF8           ) when using the 8-bit
  425   <b>/?</b>              PCRE_NO_UTF8_CHECK  )   library
  427   <b>/8</b>              PCRE_UTF16          ) when using the 16-bit
  428   <b>/?</b>              PCRE_NO_UTF16_CHECK )   library
  430   <b>/8</b>              PCRE_UTF32          ) when using the 32-bit
  431   <b>/?</b>              PCRE_NO_UTF32_CHECK )   library
  433   <b>/9</b>              PCRE_NEVER_UTF
  434   <b>/A</b>              PCRE_ANCHORED
  435   <b>/C</b>              PCRE_AUTO_CALLOUT
  436   <b>/E</b>              PCRE_DOLLAR_ENDONLY
  437   <b>/f</b>              PCRE_FIRSTLINE
  438   <b>/J</b>              PCRE_DUPNAMES
  439   <b>/N</b>              PCRE_NO_AUTO_CAPTURE
  440   <b>/O</b>              PCRE_NO_AUTO_POSSESS
  441   <b>/U</b>              PCRE_UNGREEDY
  442   <b>/W</b>              PCRE_UCP
  443   <b>/X</b>              PCRE_EXTRA
  444   <b>/Y</b>              PCRE_NO_START_OPTIMIZE
  445   <b>/&#60;any&#62;</b>          PCRE_NEWLINE_ANY
  446   <b>/&#60;anycrlf&#62;</b>      PCRE_NEWLINE_ANYCRLF
  447   <b>/&#60;cr&#62;</b>           PCRE_NEWLINE_CR
  448   <b>/&#60;crlf&#62;</b>         PCRE_NEWLINE_CRLF
  449   <b>/&#60;lf&#62;</b>           PCRE_NEWLINE_LF
  450   <b>/&#60;bsr_anycrlf&#62;</b>  PCRE_BSR_ANYCRLF
  451   <b>/&#60;bsr_unicode&#62;</b>  PCRE_BSR_UNICODE
  452   <b>/&#60;JS&#62;</b>           PCRE_JAVASCRIPT_COMPAT
  453 </pre>
  454 The modifiers that are enclosed in angle brackets are literal strings as shown,
  455 including the angle brackets, but the letters within can be in either case.
  456 This example sets multiline matching with CRLF as the line ending sequence:
  457 <pre>
  458   /^abc/m&#60;CRLF&#62;
  459 </pre>
  460 As well as turning on the PCRE_UTF8/16/32 option, the <b>/8</b> modifier causes
  461 all non-printing characters in output strings to be printed using the
  462 \x{hh...} notation. Otherwise, those less than 0x100 are output in hex without
  463 the curly brackets.
  464 </P>
  465 <P>
  466 Full details of the PCRE options are given in the
  467 <a href="pcreapi.html"><b>pcreapi</b></a>
  468 documentation.
  469 </P>
  470 <br><b>
  471 Finding all matches in a string
  472 </b><br>
  473 <P>
  474 Searching for all possible matches within each subject string can be requested
  475 by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
  476 again to search the remainder of the subject string. The difference between
  477 <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
  478 <b>pcre[16|32]_exec()</b> to start searching at a new point within the entire
  479 string (which is in effect what Perl does), whereas the latter passes over a
  480 shortened substring. This makes a difference to the matching process if the
  481 pattern begins with a lookbehind assertion (including \b or \B).
  482 </P>
  483 <P>
  484 If any call to <b>pcre[16|32]_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches
  485 an empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
  486 PCRE_ANCHORED flags set in order to search for another, non-empty, match at the
  487 same point. If this second match fails, the start offset is advanced, and the
  488 normal match is retried. This imitates the way Perl handles such cases when
  489 using the <b>/g</b> modifier or the <b>split()</b> function. Normally, the start
  490 offset is advanced by one character, but if the newline convention recognizes
  491 CRLF as a newline, and the current character is CR followed by LF, an advance
  492 of two is used.
  493 </P>
  494 <br><b>
  495 Other modifiers
  496 </b><br>
  497 <P>
  498 There are yet more modifiers for controlling the way <b>pcretest</b>
  499 operates.
  500 </P>
  501 <P>
  502 The <b>/+</b> modifier requests that as well as outputting the substring that
  503 matched the entire pattern, <b>pcretest</b> should in addition output the
  504 remainder of the subject string. This is useful for tests where the subject
  505 contains multiple copies of the same substring. If the <b>+</b> modifier appears
  506 twice, the same action is taken for captured substrings. In each case the
  507 remainder is output on the following line with a plus character following the
  508 capture number. Note that this modifier must not immediately follow the /S
  509 modifier because /S+ and /S++ have other meanings.
  510 </P>
  511 <P>
  512 The <b>/=</b> modifier requests that the values of all potential captured
  513 parentheses be output after a match. By default, only those up to the highest
  514 one actually used in the match are output (corresponding to the return code
  515 from <b>pcre[16|32]_exec()</b>). Values in the offsets vector corresponding to
  516 higher numbers should be set to -1, and these are output as "&#60;unset&#62;". This
  517 modifier gives a way of checking that this is happening.
  518 </P>
  519 <P>
  520 The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
  521 output a representation of the compiled code after compilation. Normally this
  522 information contains length and offset values; however, if <b>/Z</b> is also
  523 present, this data is replaced by spaces. This is a special feature for use in
  524 the automatic test scripts; it ensures that the same output is generated for
  525 different internal link sizes.
  526 </P>
  527 <P>
  528 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
  529 <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
  530 </P>
  531 <P>
  532 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
  533 2-byte and 4-byte fields in the compiled pattern. This facility is for testing
  534 the feature in PCRE that allows it to execute patterns that were compiled on a
  535 host with a different endianness. This feature is not available when the POSIX
  536 interface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
  537 specified. See also the section about saving and reloading compiled patterns
  538 below.
  539 </P>
  540 <P>
  541 The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
  542 compiled pattern (whether it is anchored, has a fixed first character, and
  543 so on). It does this by calling <b>pcre[16|32]_fullinfo()</b> after compiling a
  544 pattern. If the pattern is studied, the results of that are also output. In
  545 this output, the word "char" means a non-UTF character, that is, the value of a
  546 single data item (8-bit, 16-bit, or 32-bit, depending on the library that is
  547 being tested).
  548 </P>
  549 <P>
  550 The <b>/K</b> modifier requests <b>pcretest</b> to show names from backtracking
  551 control verbs that are returned from calls to <b>pcre[16|32]_exec()</b>. It causes
  552 <b>pcretest</b> to create a <b>pcre[16|32]_extra</b> block if one has not already
  553 been created by a call to <b>pcre[16|32]_study()</b>, and to set the
  554 PCRE_EXTRA_MARK flag and the <b>mark</b> field within it, every time that
  555 <b>pcre[16|32]_exec()</b> is called. If the variable that the <b>mark</b> field
  556 points to is non-NULL for a match, non-match, or partial match, <b>pcretest</b>
  557 prints the string to which it points. For a match, this is shown on a line by
  558 itself, tagged with "MK:". For a non-match it is added to the message.
  559 </P>
  560 <P>
  561 The <b>/L</b> modifier must be followed directly by the name of a locale, for
  562 example,
  563 <pre>
  564   /pattern/Lfr_FR
  565 </pre>
  566 For this reason, it must be the last modifier. The given locale is set,
  567 <b>pcre[16|32]_maketables()</b> is called to build a set of character tables for
  568 the locale, and this is then passed to <b>pcre[16|32]_compile()</b> when compiling
  569 the regular expression. Without an <b>/L</b> (or <b>/T</b>) modifier, NULL is
  570 passed as the tables pointer; that is, <b>/L</b> applies only to the expression
  571 on which it appears.
  572 </P>
  573 <P>
  574 The <b>/M</b> modifier causes the size in bytes of the memory block used to hold
  575 the compiled pattern to be output. This does not include the size of the
  576 <b>pcre[16|32]</b> block; it is just the actual compiled data. If the pattern is
  577 successfully studied with the PCRE_STUDY_JIT_COMPILE option, the size of the
  578 JIT compiled code is also output.
  579 </P>
  580 <P>
  581 The <b>/Q</b> modifier is used to test the use of <b>pcre_stack_guard</b>. It
  582 must be followed by '0' or '1', specifying the return code to be given from an
  583 external function that is passed to PCRE and used for stack checking during
  584 compilation (see the
  585 <a href="pcreapi.html"><b>pcreapi</b></a>
  586 documentation for details).
  587 </P>
  588 <P>
  589 The <b>/S</b> modifier causes <b>pcre[16|32]_study()</b> to be called after the
  590 expression has been compiled, and the results used when the expression is
  591 matched. There are a number of qualifying characters that may follow <b>/S</b>.
  592 They may appear in any order.
  593 </P>
  594 <P>
  595 If <b>/S</b> is followed by an exclamation mark, <b>pcre[16|32]_study()</b> is
  596 called with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
  597 <b>pcre_extra</b> block, even when studying discovers no useful information.
  598 </P>
  599 <P>
  600 If <b>/S</b> is followed by a second S character, it suppresses studying, even
  601 if it was requested externally by the <b>-s</b> command line option. This makes
  602 it possible to specify that certain patterns are always studied, and others are
  603 never studied, independently of <b>-s</b>. This feature is used in the test
  604 files in a few cases where the output is different when the pattern is studied.
  605 </P>
  606 <P>
  607 If the <b>/S</b> modifier is followed by a + character, the call to
  608 <b>pcre[16|32]_study()</b> is made with all the JIT study options, requesting
  609 just-in-time optimization support if it is available, for both normal and
  610 partial matching. If you want to restrict the JIT compiling modes, you can
  611 follow <b>/S+</b> with a digit in the range 1 to 7:
  612 <pre>
  613   1  normal match only
  614   2  soft partial match only
  615   3  normal match and soft partial match
  616   4  hard partial match only
  617   6  soft and hard partial match
  618   7  all three modes (default)
  619 </pre>
  620 If <b>/S++</b> is used instead of <b>/S+</b> (with or without a following digit),
  621 the text "(JIT)" is added to the first output line after a match or no match
  622 when JIT-compiled code was actually used.
  623 </P>
  624 <P>
  625 Note that there is also an independent <b>/+</b> modifier; it must not be given
  626 immediately after <b>/S</b> or <b>/S+</b> because this will be misinterpreted.
  627 </P>
  628 <P>
  629 If JIT studying is successful, the compiled JIT code will automatically be used
  630 when <b>pcre[16|32]_exec()</b> is run, except when incompatible run-time options
  631 are specified. For more details, see the
  632 <a href="pcrejit.html"><b>pcrejit</b></a>
  633 documentation. See also the <b>\J</b> escape sequence below for a way of
  634 setting the size of the JIT stack.
  635 </P>
  636 <P>
  637 Finally, if <b>/S</b> is followed by a minus character, JIT compilation is
  638 suppressed, even if it was requested externally by the <b>-s</b> command line
  639 option. This makes it possible to specify that JIT is never to be used for
  640 certain patterns.
  641 </P>
  642 <P>
  643 The <b>/T</b> modifier must be followed by a single digit. It causes a specific
  644 set of built-in character tables to be passed to <b>pcre[16|32]_compile()</b>. It
  645 is used in the standard PCRE tests to check behaviour with different character
  646 tables. The digit specifies the tables as follows:
  647 <pre>
  648   0   the default ASCII tables, as distributed in
  649         pcre_chartables.c.dist
  650   1   a set of tables defining ISO 8859 characters
  651 </pre>
  652 In table 1, some characters whose codes are greater than 128 are identified as
  653 letters, digits, spaces, etc.
  654 </P>
  655 <br><b>
  656 Using the POSIX wrapper API
  657 </b><br>
  658 <P>
  659 The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
  660 API rather than its native API. This supports only the 8-bit library. When
  661 <b>/P</b> is set, the following modifiers set options for the <b>regcomp()</b>
  662 function:
  663 <pre>
  664   /i    REG_ICASE
  665   /m    REG_NEWLINE
  666   /N    REG_NOSUB
  667   /s    REG_DOTALL     )
  668   /U    REG_UNGREEDY   ) These options are not part of
  669   /W    REG_UCP        )   the POSIX standard
  670   /8    REG_UTF8       )
  671 </pre>
  672 The <b>/+</b> modifier works as described above. All other modifiers are
  673 ignored.
  674 </P>
  675 <br><b>
  676 Locking out certain modifiers
  677 </b><br>
  678 <P>
  679 PCRE can be compiled with or without support for certain features such as
  680 UTF-8/16/32 or Unicode properties. Accordingly, the standard tests are split up
  681 into a number of different files that are selected for running depending on
  682 which features are available. When updating the tests, it is all too easy to
  683 put a new test into the wrong file by mistake; for example, to put a test that
  684 requires UTF support into a file that is used when it is not available. To help
  685 detect such mistakes as early as possible, there is a facility for locking out
  686 specific modifiers. If an input line for <b>pcretest</b> starts with the string
  687 "&#60; forbid " the following sequence of characters is taken as a list of
  688 forbidden modifiers. For example, in the test files that must not use UTF or
  689 Unicode property support, this line appears:
  690 <pre>
  691   &#60; forbid 8W
  692 </pre>
  693 This locks out the /8 and /W modifiers. An immediate error is given if they are
  694 subsequently encountered. If the character string contains &#60; but not &#62;, all the
  695 multi-character modifiers that begin with &#60; are locked out. Otherwise, such
  696 modifiers must be explicitly listed, for example:
  697 <pre>
  698   &#60; forbid &#60;JS&#62;&#60;cr&#62;
  699 </pre>
  700 There must be a single space between &#60; and "forbid" for this feature to be
  701 recognised. If there is not, the line is interpreted either as a request to
  702 re-load a pre-compiled pattern (see "SAVING AND RELOADING COMPILED PATTERNS"
  703 below) or, if there is a another &#60; character, as a pattern that uses &#60; as its
  704 delimiter.
  705 </P>
  706 <br><a name="SEC7" href="#TOC1">DATA LINES</a><br>
  707 <P>
  708 Before each data line is passed to <b>pcre[16|32]_exec()</b>, leading and trailing
  709 white space is removed, and it is then scanned for \ escapes. Some of these
  710 are pretty esoteric features, intended for checking out some of the more
  711 complicated features of PCRE. If you are just testing "ordinary" regular
  712 expressions, you probably don't need any of these. The following escapes are
  713 recognized:
  714 <pre>
  715   \a         alarm (BEL, \x07)
  716   \b         backspace (\x08)
  717   \e         escape (\x27)
  718   \f         form feed (\x0c)
  719   \n         newline (\x0a)
  720   \qdd       set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
  721   \r         carriage return (\x0d)
  722   \t         tab (\x09)
  723   \v         vertical tab (\x0b)
  724   \nnn       octal character (up to 3 octal digits); always
  725                a byte unless &#62; 255 in UTF-8 or 16-bit or 32-bit mode
  726   \o{dd...}  octal character (any number of octal digits}
  727   \xhh       hexadecimal byte (up to 2 hex digits)
  728   \x{hh...}  hexadecimal character (any number of hex digits)
  729   \A         pass the PCRE_ANCHORED option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  730   \B         pass the PCRE_NOTBOL option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  731   \Cdd       call pcre[16|32]_copy_substring() for substring dd after a successful match (number less than 32)
  732   \Cname     call pcre[16|32]_copy_named_substring() for substring "name" after a successful match (name termin-
  733                ated by next non alphanumeric character)
  734   \C+        show the current captured substrings at callout time
  735   \C-        do not supply a callout function
  736   \C!n       return 1 instead of 0 when callout number n is reached
  737   \C!n!m     return 1 instead of 0 when callout number n is reached for the nth time
  738   \C*n       pass the number n (may be negative) as callout data; this is used as the callout return value
  739   \D         use the <b>pcre[16|32]_dfa_exec()</b> match function
  740   \F         only shortest match for <b>pcre[16|32]_dfa_exec()</b>
  741   \Gdd       call pcre[16|32]_get_substring() for substring dd after a successful match (number less than 32)
  742   \Gname     call pcre[16|32]_get_named_substring() for substring "name" after a successful match (name termin-
  743                ated by next non-alphanumeric character)
  744   \Jdd       set up a JIT stack of dd kilobytes maximum (any number of digits)
  745   \L         call pcre[16|32]_get_substringlist() after a successful match
  746   \M         discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
  747   \N         pass the PCRE_NOTEMPTY option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>; if used twice, pass the
  748                PCRE_NOTEMPTY_ATSTART option
  749   \Odd       set the size of the output vector passed to <b>pcre[16|32]_exec()</b> to dd (any number of digits)
  750   \P         pass the PCRE_PARTIAL_SOFT option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>; if used twice, pass the
  751                PCRE_PARTIAL_HARD option
  752   \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
  753   \R         pass the PCRE_DFA_RESTART option to <b>pcre[16|32]_dfa_exec()</b>
  754   \S         output details of memory get/free calls during matching
  755   \Y         pass the PCRE_NO_START_OPTIMIZE option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  756   \Z         pass the PCRE_NOTEOL option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  757   \?         pass the PCRE_NO_UTF[8|16|32]_CHECK option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  758   \&#62;dd       start the match at offset dd (optional "-"; then any number of digits); this sets the <i>startoffset</i>
  759                argument for <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  760   \&#60;cr&#62;      pass the PCRE_NEWLINE_CR option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  761   \&#60;lf&#62;      pass the PCRE_NEWLINE_LF option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  762   \&#60;crlf&#62;    pass the PCRE_NEWLINE_CRLF option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  763   \&#60;anycrlf&#62; pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  764   \&#60;any&#62;     pass the PCRE_NEWLINE_ANY option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  765 </pre>
  766 The use of \x{hh...} is not dependent on the use of the <b>/8</b> modifier on
  767 the pattern. It is recognized always. There may be any number of hexadecimal
  768 digits inside the braces; invalid values provoke error messages.
  769 </P>
  770 <P>
  771 Note that \xhh specifies one byte rather than one character in UTF-8 mode;
  772 this makes it possible to construct invalid UTF-8 sequences for testing
  773 purposes. On the other hand, \x{hh} is interpreted as a UTF-8 character in
  774 UTF-8 mode, generating more than one byte if the value is greater than 127.
  775 When testing the 8-bit library not in UTF-8 mode, \x{hh} generates one byte
  776 for values less than 256, and causes an error for greater values.
  777 </P>
  778 <P>
  779 In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
  780 possible to construct invalid UTF-16 sequences for testing purposes.
  781 </P>
  782 <P>
  783 In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This makes it
  784 possible to construct invalid UTF-32 sequences for testing purposes.
  785 </P>
  786 <P>
  787 The escapes that specify line ending sequences are literal strings, exactly as
  788 shown. No more than one newline setting should be present in any data line.
  789 </P>
  790 <P>
  791 A backslash followed by anything else just escapes the anything else. If
  792 the very last character is a backslash, it is ignored. This gives a way of
  793 passing an empty line as data, since a real empty line terminates the data
  794 input.
  795 </P>
  796 <P>
  797 The <b>\J</b> escape provides a way of setting the maximum stack size that is
  798 used by the just-in-time optimization code. It is ignored if JIT optimization
  799 is not being used. Providing a stack that is larger than the default 32K is
  800 necessary only for very complicated patterns.
  801 </P>
  802 <P>
  803 If \M is present, <b>pcretest</b> calls <b>pcre[16|32]_exec()</b> several times,
  804 with different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
  805 fields of the <b>pcre[16|32]_extra</b> data structure, until it finds the minimum
  806 numbers for each parameter that allow <b>pcre[16|32]_exec()</b> to complete without
  807 error. Because this is testing a specific feature of the normal interpretive
  808 <b>pcre[16|32]_exec()</b> execution, the use of any JIT optimization that might
  809 have been set up by the <b>/S+</b> qualifier of <b>-s+</b> option is disabled.
  810 </P>
  811 <P>
  812 The <i>match_limit</i> number is a measure of the amount of backtracking
  813 that takes place, and checking it out can be instructive. For most simple
  814 matches, the number is quite small, but for patterns with very large numbers of
  815 matching possibilities, it can become large very quickly with increasing length
  816 of subject string. The <i>match_limit_recursion</i> number is a measure of how
  817 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is
  818 needed to complete the match attempt.
  819 </P>
  820 <P>
  821 When \O is used, the value specified may be higher or lower than the size set
  822 by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
  823 the call of <b>pcre[16|32]_exec()</b> for the line in which it appears.
  824 </P>
  825 <P>
  826 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
  827 API to be used, the only option-setting sequences that have any effect are \B,
  828 \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,
  829 to be passed to <b>regexec()</b>.
  830 </P>
  831 <br><a name="SEC8" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
  832 <P>
  833 By default, <b>pcretest</b> uses the standard PCRE matching function,
  834 <b>pcre[16|32]_exec()</b> to match each data line. PCRE also supports an
  835 alternative matching function, <b>pcre[16|32]_dfa_test()</b>, which operates in a
  836 different way, and has some restrictions. The differences between the two
  837 functions are described in the
  838 <a href="pcrematching.html"><b>pcrematching</b></a>
  839 documentation.
  840 </P>
  841 <P>
  842 If a data line contains the \D escape sequence, or if the command line
  843 contains the <b>-dfa</b> option, the alternative matching function is used.
  844 This function finds all possible matches at a given point. If, however, the \F
  845 escape sequence is present in the data line, it stops after the first match is
  846 found. This is always the shortest possible match.
  847 </P>
  848 <br><a name="SEC9" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
  849 <P>
  850 This section describes the output when the normal matching function,
  851 <b>pcre[16|32]_exec()</b>, is being used.
  852 </P>
  853 <P>
  854 When a match succeeds, <b>pcretest</b> outputs the list of captured substrings
  855 that <b>pcre[16|32]_exec()</b> returns, starting with number 0 for the string that
  856 matched the whole pattern. Otherwise, it outputs "No match" when the return is
  857 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
  858 substring when <b>pcre[16|32]_exec()</b> returns PCRE_ERROR_PARTIAL. (Note that
  859 this is the entire substring that was inspected during the partial match; it
  860 may include characters before the actual match start if a lookbehind assertion,
  861 \K, \b, or \B was involved.) For any other return, <b>pcretest</b> outputs
  862 the PCRE negative error number and a short descriptive phrase. If the error is
  863 a failed UTF string check, the offset of the start of the failing character and
  864 the reason code are also output, provided that the size of the output vector is
  865 at least two. Here is an example of an interactive <b>pcretest</b> run.
  866 <pre>
  867   $ pcretest
  868   PCRE version 8.13 2011-04-30
  870     re&#62; /^abc(\d+)/
  871   data&#62; abc123
  872    0: abc123
  873    1: 123
  874   data&#62; xyz
  875   No match
  876 </pre>
  877 Unset capturing substrings that are not followed by one that is set are not
  878 returned by <b>pcre[16|32]_exec()</b>, and are not shown by <b>pcretest</b>. In the
  879 following example, there are two capturing substrings, but when the first data
  880 line is matched, the second, unset substring is not shown. An "internal" unset
  881 substring is shown as "&#60;unset&#62;", as for the second data line.
  882 <pre>
  883     re&#62; /(a)|(b)/
  884   data&#62; a
  885    0: a
  886    1: a
  887   data&#62; b
  888    0: b
  889    1: &#60;unset&#62;
  890    2: b
  891 </pre>
  892 If the strings contain any non-printing characters, they are output as \xhh
  893 escapes if the value is less than 256 and UTF mode is not set. Otherwise they
  894 are output as \x{hh...} escapes. See below for the definition of non-printing
  895 characters. If the pattern has the <b>/+</b> modifier, the output for substring
  896 0 is followed by the the rest of the subject string, identified by "0+" like
  897 this:
  898 <pre>
  899     re&#62; /cat/+
  900   data&#62; cataract
  901    0: cat
  902    0+ aract
  903 </pre>
  904 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
  905 matching attempts are output in sequence, like this:
  906 <pre>
  907     re&#62; /\Bi(\w\w)/g
  908   data&#62; Mississippi
  909    0: iss
  910    1: ss
  911    0: iss
  912    1: ss
  913    0: ipp
  914    1: pp
  915 </pre>
  916 "No match" is output only if the first match attempt fails. Here is an example
  917 of a failure message (the offset 4 that is specified by \&#62;4 is past the end of
  918 the subject string):
  919 <pre>
  920     re&#62; /xyz/
  921   data&#62; xyz\&#62;4
  922   Error -24 (bad offset value)
  923 </PRE>
  924 </P>
  925 <P>
  926 If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
  927 data line that is successfully matched, the substrings extracted by the
  928 convenience functions are output with C, G, or L after the string number
  929 instead of a colon. This is in addition to the normal full list. The string
  930 length (that is, the return from the extraction function) is given in
  931 parentheses after each string for <b>\C</b> and <b>\G</b>.
  932 </P>
  933 <P>
  934 Note that whereas patterns can be continued over several lines (a plain "&#62;"
  935 prompt is used for continuations), data lines may not. However newlines can be
  936 included in data by means of the \n escape (or \r, \r\n, etc., depending on
  937 the newline sequence setting).
  938 </P>
  939 <br><a name="SEC10" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
  940 <P>
  941 When the alternative matching function, <b>pcre[16|32]_dfa_exec()</b>, is used (by
  942 means of the \D escape sequence or the <b>-dfa</b> command line option), the
  943 output consists of a list of all the matches that start at the first point in
  944 the subject where there is at least one match. For example:
  945 <pre>
  946     re&#62; /(tang|tangerine|tan)/
  947   data&#62; yellow tangerine\D
  948    0: tangerine
  949    1: tang
  950    2: tan
  951 </pre>
  952 (Using the normal matching function on this data finds only "tang".) The
  953 longest matching string is always given first (and numbered zero). After a
  954 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
  955 partially matching substring. (Note that this is the entire substring that was
  956 inspected during the partial match; it may include characters before the actual
  957 match start if a lookbehind assertion, \K, \b, or \B was involved.)
  958 </P>
  959 <P>
  960 If <b>/g</b> is present on the pattern, the search for further matches resumes
  961 at the end of the longest match. For example:
  962 <pre>
  963     re&#62; /(tang|tangerine|tan)/g
  964   data&#62; yellow tangerine and tangy sultana\D
  965    0: tangerine
  966    1: tang
  967    2: tan
  968    0: tang
  969    1: tan
  970    0: tan
  971 </pre>
  972 Since the matching function does not support substring capture, the escape
  973 sequences that are concerned with captured substrings are not relevant.
  974 </P>
  975 <br><a name="SEC11" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
  976 <P>
  977 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
  978 indicating that the subject partially matched the pattern, you can restart the
  979 match with additional subject data by means of the \R escape sequence. For
  980 example:
  981 <pre>
  982     re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
  983   data&#62; 23ja\P\D
  984   Partial match: 23ja
  985   data&#62; n05\R\D
  986    0: n05
  987 </pre>
  988 For further information about partial matching, see the
  989 <a href="pcrepartial.html"><b>pcrepartial</b></a>
  990 documentation.
  991 </P>
  992 <br><a name="SEC12" href="#TOC1">CALLOUTS</a><br>
  993 <P>
  994 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
  995 is called during matching. This works with both matching functions. By default,
  996 the called function displays the callout number, the start and current
  997 positions in the text at the callout time, and the next pattern item to be
  998 tested. For example:
  999 <pre>
 1000   ---&#62;pqrabcdef
 1001     0    ^  ^     \d
 1002 </pre>
 1003 This output indicates that callout number 0 occurred for a match attempt
 1004 starting at the fourth character of the subject string, when the pointer was at
 1005 the seventh character of the data, and when the next pattern item was \d. Just
 1006 one circumflex is output if the start and current positions are the same.
 1007 </P>
 1008 <P>
 1009 Callouts numbered 255 are assumed to be automatic callouts, inserted as a
 1010 result of the <b>/C</b> pattern modifier. In this case, instead of showing the
 1011 callout number, the offset in the pattern, preceded by a plus, is output. For
 1012 example:
 1013 <pre>
 1014     re&#62; /\d?[A-E]\*/C
 1015   data&#62; E*
 1016   ---&#62;E*
 1017    +0 ^      \d?
 1018    +3 ^      [A-E]
 1019    +8 ^^     \*
 1020   +10 ^ ^
 1021    0: E*
 1022 </pre>
 1023 If a pattern contains (*MARK) items, an additional line is output whenever
 1024 a change of latest mark is passed to the callout function. For example:
 1025 <pre>
 1026     re&#62; /a(*MARK:X)bc/C
 1027   data&#62; abc
 1028   ---&#62;abc
 1029    +0 ^       a
 1030    +1 ^^      (*MARK:X)
 1031   +10 ^^      b
 1032   Latest Mark: X
 1033   +11 ^ ^     c
 1034   +12 ^  ^
 1035    0: abc
 1036 </pre>
 1037 The mark changes between matching "a" and "b", but stays the same for the rest
 1038 of the match, so nothing more is output. If, as a result of backtracking, the
 1039 mark reverts to being unset, the text "&#60;unset&#62;" is output.
 1040 </P>
 1041 <P>
 1042 The callout function in <b>pcretest</b> returns zero (carry on matching) by
 1043 default, but you can use a \C item in a data line (as described above) to
 1044 change this and other parameters of the callout.
 1045 </P>
 1046 <P>
 1047 Inserting callouts can be helpful when using <b>pcretest</b> to check
 1048 complicated regular expressions. For further information about callouts, see
 1049 the
 1050 <a href="pcrecallout.html"><b>pcrecallout</b></a>
 1051 documentation.
 1052 </P>
 1053 <br><a name="SEC13" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
 1054 <P>
 1055 When <b>pcretest</b> is outputting text in the compiled version of a pattern,
 1056 bytes other than 32-126 are always treated as non-printing characters are are
 1057 therefore shown as hex escapes.
 1058 </P>
 1059 <P>
 1060 When <b>pcretest</b> is outputting text that is a matched part of a subject
 1061 string, it behaves in the same way, unless a different locale has been set for
 1062 the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
 1063 function to distinguish printing and non-printing characters.
 1064 </P>
 1065 <br><a name="SEC14" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
 1066 <P>
 1067 The facilities described in this section are not available when the POSIX
 1068 interface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
 1069 specified.
 1070 </P>
 1071 <P>
 1072 When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
 1073 compiled pattern to a file, by following the modifiers with &#62; and a file name.
 1074 For example:
 1075 <pre>
 1076   /pattern/im &#62;/some/file
 1077 </pre>
 1078 See the
 1079 <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
 1080 documentation for a discussion about saving and re-using compiled patterns.
 1081 Note that if the pattern was successfully studied with JIT optimization, the
 1082 JIT data cannot be saved.
 1083 </P>
 1084 <P>
 1085 The data that is written is binary. The first eight bytes are the length of the
 1086 compiled pattern data followed by the length of the optional study data, each
 1087 written as four bytes in big-endian order (most significant byte first). If
 1088 there is no study data (either the pattern was not studied, or studying did not
 1089 return any data), the second length is zero. The lengths are followed by an
 1090 exact copy of the compiled pattern. If there is additional study data, this
 1091 (excluding any JIT data) follows immediately after the compiled pattern. After
 1092 writing the file, <b>pcretest</b> expects to read a new pattern.
 1093 </P>
 1094 <P>
 1095 A saved pattern can be reloaded into <b>pcretest</b> by specifying &#60; and a file
 1096 name instead of a pattern. There must be no space between &#60; and the file name,
 1097 which must not contain a &#60; character, as otherwise <b>pcretest</b> will
 1098 interpret the line as a pattern delimited by &#60; characters. For example:
 1099 <pre>
 1100    re&#62; &#60;/some/file
 1101   Compiled pattern loaded from /some/file
 1102   No study data
 1103 </pre>
 1104 If the pattern was previously studied with the JIT optimization, the JIT
 1105 information cannot be saved and restored, and so is lost. When the pattern has
 1106 been loaded, <b>pcretest</b> proceeds to read data lines in the usual way.
 1107 </P>
 1108 <P>
 1109 You can copy a file written by <b>pcretest</b> to a different host and reload it
 1110 there, even if the new host has opposite endianness to the one on which the
 1111 pattern was compiled. For example, you can compile on an i86 machine and run on
 1112 a SPARC machine. When a pattern is reloaded on a host with different
 1113 endianness, the confirmation message is changed to:
 1114 <pre>
 1115   Compiled pattern (byte-inverted) loaded from /some/file
 1116 </pre>
 1117 The test suite contains some saved pre-compiled patterns with different
 1118 endianness. These are reloaded using "&#60;!" instead of just "&#60;". This suppresses
 1119 the "(byte-inverted)" text so that the output is the same on all hosts. It also
 1120 forces debugging output once the pattern has been reloaded.
 1121 </P>
 1122 <P>
 1123 File names for saving and reloading can be absolute or relative, but note that
 1124 the shell facility of expanding a file name that starts with a tilde (~) is not
 1125 available.
 1126 </P>
 1127 <P>
 1128 The ability to save and reload files in <b>pcretest</b> is intended for testing
 1129 and experimentation. It is not intended for production use because only a
 1130 single pattern can be written to a file. Furthermore, there is no facility for
 1131 supplying custom character tables for use with a reloaded pattern. If the
 1132 original pattern was compiled with custom tables, an attempt to match a subject
 1133 string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
 1134 Finally, if you attempt to load a file that is not in the correct format, the
 1135 result is undefined.
 1136 </P>
 1137 <br><a name="SEC15" href="#TOC1">SEE ALSO</a><br>
 1138 <P>
 1139 <b>pcre</b>(3), <b>pcre16</b>(3), <b>pcre32</b>(3), <b>pcreapi</b>(3),
 1140 <b>pcrecallout</b>(3),
 1141 <b>pcrejit</b>, <b>pcrematching</b>(3), <b>pcrepartial</b>(d),
 1142 <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3).
 1143 </P>
 1144 <br><a name="SEC16" href="#TOC1">AUTHOR</a><br>
 1145 <P>
 1146 Philip Hazel
 1147 <br>
 1148 University Computing Service
 1149 <br>
 1150 Cambridge CB2 3QH, England.
 1151 <br>
 1152 </P>
 1153 <br><a name="SEC17" href="#TOC1">REVISION</a><br>
 1154 <P>
 1155 Last updated: 10 February 2020
 1156 <br>
 1157 Copyright &copy; 1997-2020 University of Cambridge.
 1158 <br>
 1159 <p>
 1160 Return to the <a href="index.html">PCRE index page</a>.
 1161 </p>