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    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>
   25 <li><a name="TOC10" href="#SEC10">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</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 both the 8-bit library has been built, this option causes the 8-bit library
  103 to be used (which is the default); if the 8-bit library has not been built,
  104 this option causes an error.
  105 </P>
  106 <P>
  107 <b>-16</b>
  108 If both the 8-bit or the 32-bit, and the 16-bit libraries have been built, this
  109 option causes the 16-bit library to be used. If only the 16-bit library has been
  110 built, this is the default (so has no effect). If only the 8-bit or the 32-bit
  111 library has been built, this option causes an error.
  112 </P>
  113 <P>
  114 <b>-32</b>
  115 If both the 8-bit or the 16-bit, and the 32-bit libraries have been built, this
  116 option causes the 32-bit library to be used. If only the 32-bit library has been
  117 built, this is the default (so has no effect). If only the 8-bit or the 16-bit
  118 library has been built, this option causes an error.
  119 </P>
  120 <P>
  121 <b>-b</b>
  122 Behave as if each pattern has the <b>/B</b> (show byte code) modifier; the
  123 internal form is output after compilation.
  124 </P>
  125 <P>
  126 <b>-C</b>
  127 Output the version number of the PCRE library, and all available information
  128 about the optional features that are included, and then exit with zero exit
  129 code. All other options are ignored.
  130 </P>
  131 <P>
  132 <b>-C</b> <i>option</i>
  133 Output information about a specific build-time option, then exit. This
  134 functionality is intended for use in scripts such as <b>RunTest</b>. The
  135 following options output the value and set the exit code as indicated:
  136 <pre>
  137   ebcdic-nl  the code for LF (= NL) in an EBCDIC environment:
  138                0x15 or 0x25
  139                0 if used in an ASCII environment
  140                exit code is always 0
  141   linksize   the configured internal link size (2, 3, or 4)
  142                exit code is set to the link size
  143   newline    the default newline setting:
  144                CR, LF, CRLF, ANYCRLF, or ANY
  145                exit code is always 0
  146   bsr        the default setting for what \R matches:
  147                ANYCRLF or ANY
  148                exit code is always 0
  149 </pre>
  150 The following options output 1 for true or 0 for false, and set the exit code
  151 to the same value:
  152 <pre>
  153   ebcdic     compiled for an EBCDIC environment
  154   jit        just-in-time support is available
  155   pcre16     the 16-bit library was built
  156   pcre32     the 32-bit library was built
  157   pcre8      the 8-bit library was built
  158   ucp        Unicode property support is available
  159   utf        UTF-8 and/or UTF-16 and/or UTF-32 support
  160                is available
  161 </pre>
  162 If an unknown option is given, an error message is output; the exit code is 0.
  163 </P>
  164 <P>
  165 <b>-d</b>
  166 Behave as if each pattern has the <b>/D</b> (debug) modifier; the internal
  167 form and information about the compiled pattern is output after compilation;
  168 <b>-d</b> is equivalent to <b>-b -i</b>.
  169 </P>
  170 <P>
  171 <b>-dfa</b>
  172 Behave as if each data line contains the \D escape sequence; this causes the
  173 alternative matching function, <b>pcre[16|32]_dfa_exec()</b>, to be used instead
  174 of the standard <b>pcre[16|32]_exec()</b> function (more detail is given below).
  175 </P>
  176 <P>
  177 <b>-help</b>
  178 Output a brief summary these options and then exit.
  179 </P>
  180 <P>
  181 <b>-i</b>
  182 Behave as if each pattern has the <b>/I</b> modifier; information about the
  183 compiled pattern is given after compilation.
  184 </P>
  185 <P>
  186 <b>-M</b>
  187 Behave as if each data line contains the \M escape sequence; this causes
  188 PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by
  189 calling <b>pcre[16|32]_exec()</b> repeatedly with different limits.
  190 </P>
  191 <P>
  192 <b>-m</b>
  193 Output the size of each compiled pattern after it has been compiled. This is
  194 equivalent to adding <b>/M</b> to each regular expression. The size is given in
  195 bytes for both libraries.
  196 </P>
  197 <P>
  198 <b>-O</b>
  199 Behave as if each pattern has the <b>/O</b> modifier, that is disable
  200 auto-possessification for all patterns.
  201 </P>
  202 <P>
  203 <b>-o</b> <i>osize</i>
  204 Set the number of elements in the output vector that is used when calling
  205 <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b> to be <i>osize</i>. The
  206 default value is 45, which is enough for 14 capturing subexpressions for
  207 <b>pcre[16|32]_exec()</b> or 22 different matches for
  208 <b>pcre[16|32]_dfa_exec()</b>.
  209 The vector size can be changed for individual matching calls by including \O
  210 in the data line (see below).
  211 </P>
  212 <P>
  213 <b>-p</b>
  214 Behave as if each pattern has the <b>/P</b> modifier; the POSIX wrapper API is
  215 used to call PCRE. None of the other options has any effect when <b>-p</b> is
  216 set. This option can be used only with the 8-bit library.
  217 </P>
  218 <P>
  219 <b>-q</b>
  220 Do not output the version number of <b>pcretest</b> at the start of execution.
  221 </P>
  222 <P>
  223 <b>-S</b> <i>size</i>
  224 On Unix-like systems, set the size of the run-time stack to <i>size</i>
  225 megabytes.
  226 </P>
  227 <P>
  228 <b>-s</b> or <b>-s+</b>
  229 Behave as if each pattern has the <b>/S</b> modifier; in other words, force each
  230 pattern to be studied. If <b>-s+</b> is used, all the JIT compile options are
  231 passed to <b>pcre[16|32]_study()</b>, causing just-in-time optimization to be set
  232 up if it is available, for both full and partial matching. Specific JIT compile
  233 options can be selected by following <b>-s+</b> with a digit in the range 1 to
  234 7, which selects the JIT compile modes as follows:
  235 <pre>
  236   1  normal match only
  237   2  soft partial match only
  238   3  normal match and soft partial match
  239   4  hard partial match only
  240   6  soft and hard partial match
  241   7  all three modes (default)
  242 </pre>
  243 If <b>-s++</b> is used instead of <b>-s+</b> (with or without a following digit),
  244 the text "(JIT)" is added to the first output line after a match or no match
  245 when JIT-compiled code was actually used.
  246 <br>
  247 <br>
  248 Note that there are pattern options that can override <b>-s</b>, either
  249 specifying no studying at all, or suppressing JIT compilation.
  250 <br>
  251 <br>
  252 If the <b>/I</b> or <b>/D</b> option is present on a pattern (requesting output
  253 about the compiled pattern), information about the result of studying is not
  254 included when studying is caused only by <b>-s</b> and neither <b>-i</b> nor
  255 <b>-d</b> is present on the command line. This behaviour means that the output
  256 from tests that are run with and without <b>-s</b> should be identical, except
  257 when options that output information about the actual running of a match are
  258 set.
  259 <br>
  260 <br>
  261 The <b>-M</b>, <b>-t</b>, and <b>-tm</b> options, which give information about
  262 resources used, are likely to produce different output with and without
  263 <b>-s</b>. Output may also differ if the <b>/C</b> option is present on an
  264 individual pattern. This uses callouts to trace the the matching process, and
  265 this may be different between studied and non-studied patterns. If the pattern
  266 contains (*MARK) items there may also be differences, for the same reason. The
  267 <b>-s</b> command line option can be overridden for specific patterns that
  268 should never be studied (see the <b>/S</b> pattern modifier below).
  269 </P>
  270 <P>
  271 <b>-t</b>
  272 Run each compile, study, and match many times with a timer, and output the
  273 resulting times per compile, study, or match (in milliseconds). Do not set
  274 <b>-m</b> with <b>-t</b>, because you will then get the size output a zillion
  275 times, and the timing will be distorted. You can control the number of
  276 iterations that are used for timing by following <b>-t</b> with a number (as a
  277 separate item on the command line). For example, "-t 1000" iterates 1000 times.
  278 The default is to iterate 500000 times.
  279 </P>
  280 <P>
  281 <b>-tm</b>
  282 This is like <b>-t</b> except that it times only the matching phase, not the
  283 compile or study phases.
  284 </P>
  285 <P>
  286 <b>-T</b> <b>-TM</b>
  287 These behave like <b>-t</b> and <b>-tm</b>, but in addition, at the end of a run,
  288 the total times for all compiles, studies, and matches are output.
  289 </P>
  290 <br><a name="SEC5" href="#TOC1">DESCRIPTION</a><br>
  291 <P>
  292 If <b>pcretest</b> is given two filename arguments, it reads from the first and
  293 writes to the second. If it is given only one filename argument, it reads from
  294 that file and writes to stdout. Otherwise, it reads from stdin and writes to
  295 stdout, and prompts for each line of input, using "re&#62;" to prompt for regular
  296 expressions, and "data&#62;" to prompt for data lines.
  297 </P>
  298 <P>
  299 When <b>pcretest</b> is built, a configuration option can specify that it should
  300 be linked with the <b>libreadline</b> library. When this is done, if the input
  301 is from a terminal, it is read using the <b>readline()</b> function. This
  302 provides line-editing and history facilities. The output from the <b>-help</b>
  303 option states whether or not <b>readline()</b> will be used.
  304 </P>
  305 <P>
  306 The program handles any number of sets of input on a single input file. Each
  307 set starts with a regular expression, and continues with any number of data
  308 lines to be matched against that pattern.
  309 </P>
  310 <P>
  311 Each data line is matched separately and independently. If you want to do
  312 multi-line matches, you have to use the \n escape sequence (or \r or \r\n,
  313 etc., depending on the newline setting) in a single line of input to encode the
  314 newline sequences. There is no limit on the length of data lines; the input
  315 buffer is automatically extended if it is too small.
  316 </P>
  317 <P>
  318 An empty line signals the end of the data lines, at which point a new regular
  319 expression is read. The regular expressions are given enclosed in any
  320 non-alphanumeric delimiters other than backslash, for example:
  321 <pre>
  322   /(a|bc)x+yz/
  323 </pre>
  324 White space before the initial delimiter is ignored. A regular expression may
  325 be continued over several input lines, in which case the newline characters are
  326 included within it. It is possible to include the delimiter within the pattern
  327 by escaping it, for example
  328 <pre>
  329   /abc\/def/
  330 </pre>
  331 If you do so, the escape and the delimiter form part of the pattern, but since
  332 delimiters are always non-alphanumeric, this does not affect its interpretation.
  333 If the terminating delimiter is immediately followed by a backslash, for
  334 example,
  335 <pre>
  336   /abc/\
  337 </pre>
  338 then a backslash is added to the end of the pattern. This is done to provide a
  339 way of testing the error condition that arises if a pattern finishes with a
  340 backslash, because
  341 <pre>
  342   /abc\/
  343 </pre>
  344 is interpreted as the first line of a pattern that starts with "abc/", causing
  345 pcretest to read the next line as a continuation of the regular expression.
  346 </P>
  347 <br><a name="SEC6" href="#TOC1">PATTERN MODIFIERS</a><br>
  348 <P>
  349 A pattern may be followed by any number of modifiers, which are mostly single
  350 characters, though some of these can be qualified by further characters.
  351 Following Perl usage, these are referred to below as, for example, "the
  352 <b>/i</b> modifier", even though the delimiter of the pattern need not always be
  353 a slash, and no slash is used when writing modifiers. White space may appear
  354 between the final pattern delimiter and the first modifier, and between the
  355 modifiers themselves. For reference, here is a complete list of modifiers. They
  356 fall into several groups that are described in detail in the following
  357 sections.
  358 <pre>
  359   <b>/8</b>              set UTF mode
  360   <b>/9</b>              set PCRE_NEVER_UTF (locks out UTF mode)
  361   <b>/?</b>              disable UTF validity check
  362   <b>/+</b>              show remainder of subject after match
  363   <b>/=</b>              show all captures (not just those that are set)
  364 
  365   <b>/A</b>              set PCRE_ANCHORED
  366   <b>/B</b>              show compiled code
  367   <b>/C</b>              set PCRE_AUTO_CALLOUT
  368   <b>/D</b>              same as <b>/B</b> plus <b>/I</b>
  369   <b>/E</b>              set PCRE_DOLLAR_ENDONLY
  370   <b>/F</b>              flip byte order in compiled pattern
  371   <b>/f</b>              set PCRE_FIRSTLINE
  372   <b>/G</b>              find all matches (shorten string)
  373   <b>/g</b>              find all matches (use startoffset)
  374   <b>/I</b>              show information about pattern
  375   <b>/i</b>              set PCRE_CASELESS
  376   <b>/J</b>              set PCRE_DUPNAMES
  377   <b>/K</b>              show backtracking control names
  378   <b>/L</b>              set locale
  379   <b>/M</b>              show compiled memory size
  380   <b>/m</b>              set PCRE_MULTILINE
  381   <b>/N</b>              set PCRE_NO_AUTO_CAPTURE
  382   <b>/O</b>              set PCRE_NO_AUTO_POSSESS
  383   <b>/P</b>              use the POSIX wrapper
  384   <b>/Q</b>              test external stack check function
  385   <b>/S</b>              study the pattern after compilation
  386   <b>/s</b>              set PCRE_DOTALL
  387   <b>/T</b>              select character tables
  388   <b>/U</b>              set PCRE_UNGREEDY
  389   <b>/W</b>              set PCRE_UCP
  390   <b>/X</b>              set PCRE_EXTRA
  391   <b>/x</b>              set PCRE_EXTENDED
  392   <b>/Y</b>              set PCRE_NO_START_OPTIMIZE
  393   <b>/Z</b>              don't show lengths in <b>/B</b> output
  394 
  395   <b>/&#60;any&#62;</b>          set PCRE_NEWLINE_ANY
  396   <b>/&#60;anycrlf&#62;</b>      set PCRE_NEWLINE_ANYCRLF
  397   <b>/&#60;cr&#62;</b>           set PCRE_NEWLINE_CR
  398   <b>/&#60;crlf&#62;</b>         set PCRE_NEWLINE_CRLF
  399   <b>/&#60;lf&#62;</b>           set PCRE_NEWLINE_LF
  400   <b>/&#60;bsr_anycrlf&#62;</b>  set PCRE_BSR_ANYCRLF
  401   <b>/&#60;bsr_unicode&#62;</b>  set PCRE_BSR_UNICODE
  402   <b>/&#60;JS&#62;</b>           set PCRE_JAVASCRIPT_COMPAT
  403 
  404 </PRE>
  405 </P>
  406 <br><b>
  407 Perl-compatible modifiers
  408 </b><br>
  409 <P>
  410 The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
  411 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
  412 <b>pcre[16|32]_compile()</b> is called. These four modifier letters have the same
  413 effect as they do in Perl. For example:
  414 <pre>
  415   /caseless/i
  416 
  417 </PRE>
  418 </P>
  419 <br><b>
  420 Modifiers for other PCRE options
  421 </b><br>
  422 <P>
  423 The following table shows additional modifiers for setting PCRE compile-time
  424 options that do not correspond to anything in Perl:
  425 <pre>
  426   <b>/8</b>              PCRE_UTF8           ) when using the 8-bit
  427   <b>/?</b>              PCRE_NO_UTF8_CHECK  )   library
  428 
  429   <b>/8</b>              PCRE_UTF16          ) when using the 16-bit
  430   <b>/?</b>              PCRE_NO_UTF16_CHECK )   library
  431 
  432   <b>/8</b>              PCRE_UTF32          ) when using the 32-bit
  433   <b>/?</b>              PCRE_NO_UTF32_CHECK )   library
  434 
  435   <b>/9</b>              PCRE_NEVER_UTF
  436   <b>/A</b>              PCRE_ANCHORED
  437   <b>/C</b>              PCRE_AUTO_CALLOUT
  438   <b>/E</b>              PCRE_DOLLAR_ENDONLY
  439   <b>/f</b>              PCRE_FIRSTLINE
  440   <b>/J</b>              PCRE_DUPNAMES
  441   <b>/N</b>              PCRE_NO_AUTO_CAPTURE
  442   <b>/O</b>              PCRE_NO_AUTO_POSSESS
  443   <b>/U</b>              PCRE_UNGREEDY
  444   <b>/W</b>              PCRE_UCP
  445   <b>/X</b>              PCRE_EXTRA
  446   <b>/Y</b>              PCRE_NO_START_OPTIMIZE
  447   <b>/&#60;any&#62;</b>          PCRE_NEWLINE_ANY
  448   <b>/&#60;anycrlf&#62;</b>      PCRE_NEWLINE_ANYCRLF
  449   <b>/&#60;cr&#62;</b>           PCRE_NEWLINE_CR
  450   <b>/&#60;crlf&#62;</b>         PCRE_NEWLINE_CRLF
  451   <b>/&#60;lf&#62;</b>           PCRE_NEWLINE_LF
  452   <b>/&#60;bsr_anycrlf&#62;</b>  PCRE_BSR_ANYCRLF
  453   <b>/&#60;bsr_unicode&#62;</b>  PCRE_BSR_UNICODE
  454   <b>/&#60;JS&#62;</b>           PCRE_JAVASCRIPT_COMPAT
  455 </pre>
  456 The modifiers that are enclosed in angle brackets are literal strings as shown,
  457 including the angle brackets, but the letters within can be in either case.
  458 This example sets multiline matching with CRLF as the line ending sequence:
  459 <pre>
  460   /^abc/m&#60;CRLF&#62;
  461 </pre>
  462 As well as turning on the PCRE_UTF8/16/32 option, the <b>/8</b> modifier causes
  463 all non-printing characters in output strings to be printed using the
  464 \x{hh...} notation. Otherwise, those less than 0x100 are output in hex without
  465 the curly brackets.
  466 </P>
  467 <P>
  468 Full details of the PCRE options are given in the
  469 <a href="pcreapi.html"><b>pcreapi</b></a>
  470 documentation.
  471 </P>
  472 <br><b>
  473 Finding all matches in a string
  474 </b><br>
  475 <P>
  476 Searching for all possible matches within each subject string can be requested
  477 by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
  478 again to search the remainder of the subject string. The difference between
  479 <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
  480 <b>pcre[16|32]_exec()</b> to start searching at a new point within the entire
  481 string (which is in effect what Perl does), whereas the latter passes over a
  482 shortened substring. This makes a difference to the matching process if the
  483 pattern begins with a lookbehind assertion (including \b or \B).
  484 </P>
  485 <P>
  486 If any call to <b>pcre[16|32]_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches
  487 an empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
  488 PCRE_ANCHORED flags set in order to search for another, non-empty, match at the
  489 same point. If this second match fails, the start offset is advanced, and the
  490 normal match is retried. This imitates the way Perl handles such cases when
  491 using the <b>/g</b> modifier or the <b>split()</b> function. Normally, the start
  492 offset is advanced by one character, but if the newline convention recognizes
  493 CRLF as a newline, and the current character is CR followed by LF, an advance
  494 of two is used.
  495 </P>
  496 <br><b>
  497 Other modifiers
  498 </b><br>
  499 <P>
  500 There are yet more modifiers for controlling the way <b>pcretest</b>
  501 operates.
  502 </P>
  503 <P>
  504 The <b>/+</b> modifier requests that as well as outputting the substring that
  505 matched the entire pattern, <b>pcretest</b> should in addition output the
  506 remainder of the subject string. This is useful for tests where the subject
  507 contains multiple copies of the same substring. If the <b>+</b> modifier appears
  508 twice, the same action is taken for captured substrings. In each case the
  509 remainder is output on the following line with a plus character following the
  510 capture number. Note that this modifier must not immediately follow the /S
  511 modifier because /S+ and /S++ have other meanings.
  512 </P>
  513 <P>
  514 The <b>/=</b> modifier requests that the values of all potential captured
  515 parentheses be output after a match. By default, only those up to the highest
  516 one actually used in the match are output (corresponding to the return code
  517 from <b>pcre[16|32]_exec()</b>). Values in the offsets vector corresponding to
  518 higher numbers should be set to -1, and these are output as "&#60;unset&#62;". This
  519 modifier gives a way of checking that this is happening.
  520 </P>
  521 <P>
  522 The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
  523 output a representation of the compiled code after compilation. Normally this
  524 information contains length and offset values; however, if <b>/Z</b> is also
  525 present, this data is replaced by spaces. This is a special feature for use in
  526 the automatic test scripts; it ensures that the same output is generated for
  527 different internal link sizes.
  528 </P>
  529 <P>
  530 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
  531 <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
  532 </P>
  533 <P>
  534 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
  535 2-byte and 4-byte fields in the compiled pattern. This facility is for testing
  536 the feature in PCRE that allows it to execute patterns that were compiled on a
  537 host with a different endianness. This feature is not available when the POSIX
  538 interface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
  539 specified. See also the section about saving and reloading compiled patterns
  540 below.
  541 </P>
  542 <P>
  543 The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
  544 compiled pattern (whether it is anchored, has a fixed first character, and
  545 so on). It does this by calling <b>pcre[16|32]_fullinfo()</b> after compiling a
  546 pattern. If the pattern is studied, the results of that are also output. In
  547 this output, the word "char" means a non-UTF character, that is, the value of a
  548 single data item (8-bit, 16-bit, or 32-bit, depending on the library that is
  549 being tested).
  550 </P>
  551 <P>
  552 The <b>/K</b> modifier requests <b>pcretest</b> to show names from backtracking
  553 control verbs that are returned from calls to <b>pcre[16|32]_exec()</b>. It causes
  554 <b>pcretest</b> to create a <b>pcre[16|32]_extra</b> block if one has not already
  555 been created by a call to <b>pcre[16|32]_study()</b>, and to set the
  556 PCRE_EXTRA_MARK flag and the <b>mark</b> field within it, every time that
  557 <b>pcre[16|32]_exec()</b> is called. If the variable that the <b>mark</b> field
  558 points to is non-NULL for a match, non-match, or partial match, <b>pcretest</b>
  559 prints the string to which it points. For a match, this is shown on a line by
  560 itself, tagged with "MK:". For a non-match it is added to the message.
  561 </P>
  562 <P>
  563 The <b>/L</b> modifier must be followed directly by the name of a locale, for
  564 example,
  565 <pre>
  566   /pattern/Lfr_FR
  567 </pre>
  568 For this reason, it must be the last modifier. The given locale is set,
  569 <b>pcre[16|32]_maketables()</b> is called to build a set of character tables for
  570 the locale, and this is then passed to <b>pcre[16|32]_compile()</b> when compiling
  571 the regular expression. Without an <b>/L</b> (or <b>/T</b>) modifier, NULL is
  572 passed as the tables pointer; that is, <b>/L</b> applies only to the expression
  573 on which it appears.
  574 </P>
  575 <P>
  576 The <b>/M</b> modifier causes the size in bytes of the memory block used to hold
  577 the compiled pattern to be output. This does not include the size of the
  578 <b>pcre[16|32]</b> block; it is just the actual compiled data. If the pattern is
  579 successfully studied with the PCRE_STUDY_JIT_COMPILE option, the size of the
  580 JIT compiled code is also output.
  581 </P>
  582 <P>
  583 The <b>/Q</b> modifier is used to test the use of <b>pcre_stack_guard</b>. It
  584 must be followed by '0' or '1', specifying the return code to be given from an
  585 external function that is passed to PCRE and used for stack checking during
  586 compilation (see the
  587 <a href="pcreapi.html"><b>pcreapi</b></a>
  588 documentation for details).
  589 </P>
  590 <P>
  591 The <b>/S</b> modifier causes <b>pcre[16|32]_study()</b> to be called after the
  592 expression has been compiled, and the results used when the expression is
  593 matched. There are a number of qualifying characters that may follow <b>/S</b>.
  594 They may appear in any order.
  595 </P>
  596 <P>
  597 If <b>/S</b> is followed by an exclamation mark, <b>pcre[16|32]_study()</b> is
  598 called with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
  599 <b>pcre_extra</b> block, even when studying discovers no useful information.
  600 </P>
  601 <P>
  602 If <b>/S</b> is followed by a second S character, it suppresses studying, even
  603 if it was requested externally by the <b>-s</b> command line option. This makes
  604 it possible to specify that certain patterns are always studied, and others are
  605 never studied, independently of <b>-s</b>. This feature is used in the test
  606 files in a few cases where the output is different when the pattern is studied.
  607 </P>
  608 <P>
  609 If the <b>/S</b> modifier is followed by a + character, the call to
  610 <b>pcre[16|32]_study()</b> is made with all the JIT study options, requesting
  611 just-in-time optimization support if it is available, for both normal and
  612 partial matching. If you want to restrict the JIT compiling modes, you can
  613 follow <b>/S+</b> with a digit in the range 1 to 7:
  614 <pre>
  615   1  normal match only
  616   2  soft partial match only
  617   3  normal match and soft partial match
  618   4  hard partial match only
  619   6  soft and hard partial match
  620   7  all three modes (default)
  621 </pre>
  622 If <b>/S++</b> is used instead of <b>/S+</b> (with or without a following digit),
  623 the text "(JIT)" is added to the first output line after a match or no match
  624 when JIT-compiled code was actually used.
  625 </P>
  626 <P>
  627 Note that there is also an independent <b>/+</b> modifier; it must not be given
  628 immediately after <b>/S</b> or <b>/S+</b> because this will be misinterpreted.
  629 </P>
  630 <P>
  631 If JIT studying is successful, the compiled JIT code will automatically be used
  632 when <b>pcre[16|32]_exec()</b> is run, except when incompatible run-time options
  633 are specified. For more details, see the
  634 <a href="pcrejit.html"><b>pcrejit</b></a>
  635 documentation. See also the <b>\J</b> escape sequence below for a way of
  636 setting the size of the JIT stack.
  637 </P>
  638 <P>
  639 Finally, if <b>/S</b> is followed by a minus character, JIT compilation is
  640 suppressed, even if it was requested externally by the <b>-s</b> command line
  641 option. This makes it possible to specify that JIT is never to be used for
  642 certain patterns.
  643 </P>
  644 <P>
  645 The <b>/T</b> modifier must be followed by a single digit. It causes a specific
  646 set of built-in character tables to be passed to <b>pcre[16|32]_compile()</b>. It
  647 is used in the standard PCRE tests to check behaviour with different character
  648 tables. The digit specifies the tables as follows:
  649 <pre>
  650   0   the default ASCII tables, as distributed in
  651         pcre_chartables.c.dist
  652   1   a set of tables defining ISO 8859 characters
  653 </pre>
  654 In table 1, some characters whose codes are greater than 128 are identified as
  655 letters, digits, spaces, etc.
  656 </P>
  657 <br><b>
  658 Using the POSIX wrapper API
  659 </b><br>
  660 <P>
  661 The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
  662 API rather than its native API. This supports only the 8-bit library. When
  663 <b>/P</b> is set, the following modifiers set options for the <b>regcomp()</b>
  664 function:
  665 <pre>
  666   /i    REG_ICASE
  667   /m    REG_NEWLINE
  668   /N    REG_NOSUB
  669   /s    REG_DOTALL     )
  670   /U    REG_UNGREEDY   ) These options are not part of
  671   /W    REG_UCP        )   the POSIX standard
  672   /8    REG_UTF8       )
  673 </pre>
  674 The <b>/+</b> modifier works as described above. All other modifiers are
  675 ignored.
  676 </P>
  677 <br><b>
  678 Locking out certain modifiers
  679 </b><br>
  680 <P>
  681 PCRE can be compiled with or without support for certain features such as
  682 UTF-8/16/32 or Unicode properties. Accordingly, the standard tests are split up
  683 into a number of different files that are selected for running depending on
  684 which features are available. When updating the tests, it is all too easy to
  685 put a new test into the wrong file by mistake; for example, to put a test that
  686 requires UTF support into a file that is used when it is not available. To help
  687 detect such mistakes as early as possible, there is a facility for locking out
  688 specific modifiers. If an input line for <b>pcretest</b> starts with the string
  689 "&#60; forbid " the following sequence of characters is taken as a list of
  690 forbidden modifiers. For example, in the test files that must not use UTF or
  691 Unicode property support, this line appears:
  692 <pre>
  693   &#60; forbid 8W
  694 </pre>
  695 This locks out the /8 and /W modifiers. An immediate error is given if they are
  696 subsequently encountered. If the character string contains &#60; but not &#62;, all the
  697 multi-character modifiers that begin with &#60; are locked out. Otherwise, such
  698 modifiers must be explicitly listed, for example:
  699 <pre>
  700   &#60; forbid &#60;JS&#62;&#60;cr&#62;
  701 </pre>
  702 There must be a single space between &#60; and "forbid" for this feature to be
  703 recognised. If there is not, the line is interpreted either as a request to
  704 re-load a pre-compiled pattern (see "SAVING AND RELOADING COMPILED PATTERNS"
  705 below) or, if there is a another &#60; character, as a pattern that uses &#60; as its
  706 delimiter.
  707 </P>
  708 <br><a name="SEC7" href="#TOC1">DATA LINES</a><br>
  709 <P>
  710 Before each data line is passed to <b>pcre[16|32]_exec()</b>, leading and trailing
  711 white space is removed, and it is then scanned for \ escapes. Some of these
  712 are pretty esoteric features, intended for checking out some of the more
  713 complicated features of PCRE. If you are just testing "ordinary" regular
  714 expressions, you probably don't need any of these. The following escapes are
  715 recognized:
  716 <pre>
  717   \a         alarm (BEL, \x07)
  718   \b         backspace (\x08)
  719   \e         escape (\x27)
  720   \f         form feed (\x0c)
  721   \n         newline (\x0a)
  722   \qdd       set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
  723   \r         carriage return (\x0d)
  724   \t         tab (\x09)
  725   \v         vertical tab (\x0b)
  726   \nnn       octal character (up to 3 octal digits); always
  727                a byte unless &#62; 255 in UTF-8 or 16-bit or 32-bit mode
  728   \o{dd...}  octal character (any number of octal digits}
  729   \xhh       hexadecimal byte (up to 2 hex digits)
  730   \x{hh...}  hexadecimal character (any number of hex digits)
  731   \A         pass the PCRE_ANCHORED option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  732   \B         pass the PCRE_NOTBOL option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  733   \Cdd       call pcre[16|32]_copy_substring() for substring dd after a successful match (number less than 32)
  734   \Cname     call pcre[16|32]_copy_named_substring() for substring "name" after a successful match (name termin-
  735                ated by next non alphanumeric character)
  736   \C+        show the current captured substrings at callout time
  737   \C-        do not supply a callout function
  738   \C!n       return 1 instead of 0 when callout number n is reached
  739   \C!n!m     return 1 instead of 0 when callout number n is reached for the nth time
  740   \C*n       pass the number n (may be negative) as callout data; this is used as the callout return value
  741   \D         use the <b>pcre[16|32]_dfa_exec()</b> match function
  742   \F         only shortest match for <b>pcre[16|32]_dfa_exec()</b>
  743   \Gdd       call pcre[16|32]_get_substring() for substring dd after a successful match (number less than 32)
  744   \Gname     call pcre[16|32]_get_named_substring() for substring "name" after a successful match (name termin-
  745                ated by next non-alphanumeric character)
  746   \Jdd       set up a JIT stack of dd kilobytes maximum (any number of digits)
  747   \L         call pcre[16|32]_get_substringlist() after a successful match
  748   \M         discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
  749   \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
  750                PCRE_NOTEMPTY_ATSTART option
  751   \Odd       set the size of the output vector passed to <b>pcre[16|32]_exec()</b> to dd (any number of digits)
  752   \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
  753                PCRE_PARTIAL_HARD option
  754   \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
  755   \R         pass the PCRE_DFA_RESTART option to <b>pcre[16|32]_dfa_exec()</b>
  756   \S         output details of memory get/free calls during matching
  757   \Y         pass the PCRE_NO_START_OPTIMIZE option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  758   \Z         pass the PCRE_NOTEOL option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  759   \?         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>
  760   \&#62;dd       start the match at offset dd (optional "-"; then any number of digits); this sets the <i>startoffset</i>
  761                argument for <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  762   \&#60;cr&#62;      pass the PCRE_NEWLINE_CR option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  763   \&#60;lf&#62;      pass the PCRE_NEWLINE_LF option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  764   \&#60;crlf&#62;    pass the PCRE_NEWLINE_CRLF option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  765   \&#60;anycrlf&#62; pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  766   \&#60;any&#62;     pass the PCRE_NEWLINE_ANY option to <b>pcre[16|32]_exec()</b> or <b>pcre[16|32]_dfa_exec()</b>
  767 </pre>
  768 The use of \x{hh...} is not dependent on the use of the <b>/8</b> modifier on
  769 the pattern. It is recognized always. There may be any number of hexadecimal
  770 digits inside the braces; invalid values provoke error messages.
  771 </P>
  772 <P>
  773 Note that \xhh specifies one byte rather than one character in UTF-8 mode;
  774 this makes it possible to construct invalid UTF-8 sequences for testing
  775 purposes. On the other hand, \x{hh} is interpreted as a UTF-8 character in
  776 UTF-8 mode, generating more than one byte if the value is greater than 127.
  777 When testing the 8-bit library not in UTF-8 mode, \x{hh} generates one byte
  778 for values less than 256, and causes an error for greater values.
  779 </P>
  780 <P>
  781 In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
  782 possible to construct invalid UTF-16 sequences for testing purposes.
  783 </P>
  784 <P>
  785 In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This makes it
  786 possible to construct invalid UTF-32 sequences for testing purposes.
  787 </P>
  788 <P>
  789 The escapes that specify line ending sequences are literal strings, exactly as
  790 shown. No more than one newline setting should be present in any data line.
  791 </P>
  792 <P>
  793 A backslash followed by anything else just escapes the anything else. If
  794 the very last character is a backslash, it is ignored. This gives a way of
  795 passing an empty line as data, since a real empty line terminates the data
  796 input.
  797 </P>
  798 <P>
  799 The <b>\J</b> escape provides a way of setting the maximum stack size that is
  800 used by the just-in-time optimization code. It is ignored if JIT optimization
  801 is not being used. Providing a stack that is larger than the default 32K is
  802 necessary only for very complicated patterns.
  803 </P>
  804 <P>
  805 If \M is present, <b>pcretest</b> calls <b>pcre[16|32]_exec()</b> several times,
  806 with different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
  807 fields of the <b>pcre[16|32]_extra</b> data structure, until it finds the minimum
  808 numbers for each parameter that allow <b>pcre[16|32]_exec()</b> to complete without
  809 error. Because this is testing a specific feature of the normal interpretive
  810 <b>pcre[16|32]_exec()</b> execution, the use of any JIT optimization that might
  811 have been set up by the <b>/S+</b> qualifier of <b>-s+</b> option is disabled.
  812 </P>
  813 <P>
  814 The <i>match_limit</i> number is a measure of the amount of backtracking
  815 that takes place, and checking it out can be instructive. For most simple
  816 matches, the number is quite small, but for patterns with very large numbers of
  817 matching possibilities, it can become large very quickly with increasing length
  818 of subject string. The <i>match_limit_recursion</i> number is a measure of how
  819 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is
  820 needed to complete the match attempt.
  821 </P>
  822 <P>
  823 When \O is used, the value specified may be higher or lower than the size set
  824 by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
  825 the call of <b>pcre[16|32]_exec()</b> for the line in which it appears.
  826 </P>
  827 <P>
  828 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
  829 API to be used, the only option-setting sequences that have any effect are \B,
  830 \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,
  831 to be passed to <b>regexec()</b>.
  832 </P>
  833 <br><a name="SEC8" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
  834 <P>
  835 By default, <b>pcretest</b> uses the standard PCRE matching function,
  836 <b>pcre[16|32]_exec()</b> to match each data line. PCRE also supports an
  837 alternative matching function, <b>pcre[16|32]_dfa_test()</b>, which operates in a
  838 different way, and has some restrictions. The differences between the two
  839 functions are described in the
  840 <a href="pcrematching.html"><b>pcrematching</b></a>
  841 documentation.
  842 </P>
  843 <P>
  844 If a data line contains the \D escape sequence, or if the command line
  845 contains the <b>-dfa</b> option, the alternative matching function is used.
  846 This function finds all possible matches at a given point. If, however, the \F
  847 escape sequence is present in the data line, it stops after the first match is
  848 found. This is always the shortest possible match.
  849 </P>
  850 <br><a name="SEC9" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
  851 <P>
  852 This section describes the output when the normal matching function,
  853 <b>pcre[16|32]_exec()</b>, is being used.
  854 </P>
  855 <P>
  856 When a match succeeds, <b>pcretest</b> outputs the list of captured substrings
  857 that <b>pcre[16|32]_exec()</b> returns, starting with number 0 for the string that
  858 matched the whole pattern. Otherwise, it outputs "No match" when the return is
  859 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
  860 substring when <b>pcre[16|32]_exec()</b> returns PCRE_ERROR_PARTIAL. (Note that
  861 this is the entire substring that was inspected during the partial match; it
  862 may include characters before the actual match start if a lookbehind assertion,
  863 \K, \b, or \B was involved.) For any other return, <b>pcretest</b> outputs
  864 the PCRE negative error number and a short descriptive phrase. If the error is
  865 a failed UTF string check, the offset of the start of the failing character and
  866 the reason code are also output, provided that the size of the output vector is
  867 at least two. Here is an example of an interactive <b>pcretest</b> run.
  868 <pre>
  869   $ pcretest
  870   PCRE version 8.13 2011-04-30
  871 
  872     re&#62; /^abc(\d+)/
  873   data&#62; abc123
  874    0: abc123
  875    1: 123
  876   data&#62; xyz
  877   No match
  878 </pre>
  879 Unset capturing substrings that are not followed by one that is set are not
  880 returned by <b>pcre[16|32]_exec()</b>, and are not shown by <b>pcretest</b>. In the
  881 following example, there are two capturing substrings, but when the first data
  882 line is matched, the second, unset substring is not shown. An "internal" unset
  883 substring is shown as "&#60;unset&#62;", as for the second data line.
  884 <pre>
  885     re&#62; /(a)|(b)/
  886   data&#62; a
  887    0: a
  888    1: a
  889   data&#62; b
  890    0: b
  891    1: &#60;unset&#62;
  892    2: b
  893 </pre>
  894 If the strings contain any non-printing characters, they are output as \xhh
  895 escapes if the value is less than 256 and UTF mode is not set. Otherwise they
  896 are output as \x{hh...} escapes. See below for the definition of non-printing
  897 characters. If the pattern has the <b>/+</b> modifier, the output for substring
  898 0 is followed by the the rest of the subject string, identified by "0+" like
  899 this:
  900 <pre>
  901     re&#62; /cat/+
  902   data&#62; cataract
  903    0: cat
  904    0+ aract
  905 </pre>
  906 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
  907 matching attempts are output in sequence, like this:
  908 <pre>
  909     re&#62; /\Bi(\w\w)/g
  910   data&#62; Mississippi
  911    0: iss
  912    1: ss
  913    0: iss
  914    1: ss
  915    0: ipp
  916    1: pp
  917 </pre>
  918 "No match" is output only if the first match attempt fails. Here is an example
  919 of a failure message (the offset 4 that is specified by \&#62;4 is past the end of
  920 the subject string):
  921 <pre>
  922     re&#62; /xyz/
  923   data&#62; xyz\&#62;4
  924   Error -24 (bad offset value)
  925 </PRE>
  926 </P>
  927 <P>
  928 If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
  929 data line that is successfully matched, the substrings extracted by the
  930 convenience functions are output with C, G, or L after the string number
  931 instead of a colon. This is in addition to the normal full list. The string
  932 length (that is, the return from the extraction function) is given in
  933 parentheses after each string for <b>\C</b> and <b>\G</b>.
  934 </P>
  935 <P>
  936 Note that whereas patterns can be continued over several lines (a plain "&#62;"
  937 prompt is used for continuations), data lines may not. However newlines can be
  938 included in data by means of the \n escape (or \r, \r\n, etc., depending on
  939 the newline sequence setting).
  940 </P>
  941 <br><a name="SEC10" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
  942 <P>
  943 When the alternative matching function, <b>pcre[16|32]_dfa_exec()</b>, is used (by
  944 means of the \D escape sequence or the <b>-dfa</b> command line option), the
  945 output consists of a list of all the matches that start at the first point in
  946 the subject where there is at least one match. For example:
  947 <pre>
  948     re&#62; /(tang|tangerine|tan)/
  949   data&#62; yellow tangerine\D
  950    0: tangerine
  951    1: tang
  952    2: tan
  953 </pre>
  954 (Using the normal matching function on this data finds only "tang".) The
  955 longest matching string is always given first (and numbered zero). After a
  956 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
  957 partially matching substring. (Note that this is the entire substring that was
  958 inspected during the partial match; it may include characters before the actual
  959 match start if a lookbehind assertion, \K, \b, or \B was involved.)
  960 </P>
  961 <P>
  962 If <b>/g</b> is present on the pattern, the search for further matches resumes
  963 at the end of the longest match. For example:
  964 <pre>
  965     re&#62; /(tang|tangerine|tan)/g
  966   data&#62; yellow tangerine and tangy sultana\D
  967    0: tangerine
  968    1: tang
  969    2: tan
  970    0: tang
  971    1: tan
  972    0: tan
  973 </pre>
  974 Since the matching function does not support substring capture, the escape
  975 sequences that are concerned with captured substrings are not relevant.
  976 </P>
  977 <br><a name="SEC11" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
  978 <P>
  979 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
  980 indicating that the subject partially matched the pattern, you can restart the
  981 match with additional subject data by means of the \R escape sequence. For
  982 example:
  983 <pre>
  984     re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
  985   data&#62; 23ja\P\D
  986   Partial match: 23ja
  987   data&#62; n05\R\D
  988    0: n05
  989 </pre>
  990 For further information about partial matching, see the
  991 <a href="pcrepartial.html"><b>pcrepartial</b></a>
  992 documentation.
  993 </P>
  994 <br><a name="SEC12" href="#TOC1">CALLOUTS</a><br>
  995 <P>
  996 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
  997 is called during matching. This works with both matching functions. By default,
  998 the called function displays the callout number, the start and current
  999 positions in the text at the callout time, and the next pattern item to be
 1000 tested. For example:
 1001 <pre>
 1002   ---&#62;pqrabcdef
 1003     0    ^  ^     \d
 1004 </pre>
 1005 This output indicates that callout number 0 occurred for a match attempt
 1006 starting at the fourth character of the subject string, when the pointer was at
 1007 the seventh character of the data, and when the next pattern item was \d. Just
 1008 one circumflex is output if the start and current positions are the same.
 1009 </P>
 1010 <P>
 1011 Callouts numbered 255 are assumed to be automatic callouts, inserted as a
 1012 result of the <b>/C</b> pattern modifier. In this case, instead of showing the
 1013 callout number, the offset in the pattern, preceded by a plus, is output. For
 1014 example:
 1015 <pre>
 1016     re&#62; /\d?[A-E]\*/C
 1017   data&#62; E*
 1018   ---&#62;E*
 1019    +0 ^      \d?
 1020    +3 ^      [A-E]
 1021    +8 ^^     \*
 1022   +10 ^ ^
 1023    0: E*
 1024 </pre>
 1025 If a pattern contains (*MARK) items, an additional line is output whenever
 1026 a change of latest mark is passed to the callout function. For example:
 1027 <pre>
 1028     re&#62; /a(*MARK:X)bc/C
 1029   data&#62; abc
 1030   ---&#62;abc
 1031    +0 ^       a
 1032    +1 ^^      (*MARK:X)
 1033   +10 ^^      b
 1034   Latest Mark: X
 1035   +11 ^ ^     c
 1036   +12 ^  ^
 1037    0: abc
 1038 </pre>
 1039 The mark changes between matching "a" and "b", but stays the same for the rest
 1040 of the match, so nothing more is output. If, as a result of backtracking, the
 1041 mark reverts to being unset, the text "&#60;unset&#62;" is output.
 1042 </P>
 1043 <P>
 1044 The callout function in <b>pcretest</b> returns zero (carry on matching) by
 1045 default, but you can use a \C item in a data line (as described above) to
 1046 change this and other parameters of the callout.
 1047 </P>
 1048 <P>
 1049 Inserting callouts can be helpful when using <b>pcretest</b> to check
 1050 complicated regular expressions. For further information about callouts, see
 1051 the
 1052 <a href="pcrecallout.html"><b>pcrecallout</b></a>
 1053 documentation.
 1054 </P>
 1055 <br><a name="SEC13" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
 1056 <P>
 1057 When <b>pcretest</b> is outputting text in the compiled version of a pattern,
 1058 bytes other than 32-126 are always treated as non-printing characters are are
 1059 therefore shown as hex escapes.
 1060 </P>
 1061 <P>
 1062 When <b>pcretest</b> is outputting text that is a matched part of a subject
 1063 string, it behaves in the same way, unless a different locale has been set for
 1064 the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
 1065 function to distinguish printing and non-printing characters.
 1066 </P>
 1067 <br><a name="SEC14" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
 1068 <P>
 1069 The facilities described in this section are not available when the POSIX
 1070 interface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
 1071 specified.
 1072 </P>
 1073 <P>
 1074 When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
 1075 compiled pattern to a file, by following the modifiers with &#62; and a file name.
 1076 For example:
 1077 <pre>
 1078   /pattern/im &#62;/some/file
 1079 </pre>
 1080 See the
 1081 <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
 1082 documentation for a discussion about saving and re-using compiled patterns.
 1083 Note that if the pattern was successfully studied with JIT optimization, the
 1084 JIT data cannot be saved.
 1085 </P>
 1086 <P>
 1087 The data that is written is binary. The first eight bytes are the length of the
 1088 compiled pattern data followed by the length of the optional study data, each
 1089 written as four bytes in big-endian order (most significant byte first). If
 1090 there is no study data (either the pattern was not studied, or studying did not
 1091 return any data), the second length is zero. The lengths are followed by an
 1092 exact copy of the compiled pattern. If there is additional study data, this
 1093 (excluding any JIT data) follows immediately after the compiled pattern. After
 1094 writing the file, <b>pcretest</b> expects to read a new pattern.
 1095 </P>
 1096 <P>
 1097 A saved pattern can be reloaded into <b>pcretest</b> by specifying &#60; and a file
 1098 name instead of a pattern. There must be no space between &#60; and the file name,
 1099 which must not contain a &#60; character, as otherwise <b>pcretest</b> will
 1100 interpret the line as a pattern delimited by &#60; characters. For example:
 1101 <pre>
 1102    re&#62; &#60;/some/file
 1103   Compiled pattern loaded from /some/file
 1104   No study data
 1105 </pre>
 1106 If the pattern was previously studied with the JIT optimization, the JIT
 1107 information cannot be saved and restored, and so is lost. When the pattern has
 1108 been loaded, <b>pcretest</b> proceeds to read data lines in the usual way.
 1109 </P>
 1110 <P>
 1111 You can copy a file written by <b>pcretest</b> to a different host and reload it
 1112 there, even if the new host has opposite endianness to the one on which the
 1113 pattern was compiled. For example, you can compile on an i86 machine and run on
 1114 a SPARC machine. When a pattern is reloaded on a host with different
 1115 endianness, the confirmation message is changed to:
 1116 <pre>
 1117   Compiled pattern (byte-inverted) loaded from /some/file
 1118 </pre>
 1119 The test suite contains some saved pre-compiled patterns with different
 1120 endianness. These are reloaded using "&#60;!" instead of just "&#60;". This suppresses
 1121 the "(byte-inverted)" text so that the output is the same on all hosts. It also
 1122 forces debugging output once the pattern has been reloaded.
 1123 </P>
 1124 <P>
 1125 File names for saving and reloading can be absolute or relative, but note that
 1126 the shell facility of expanding a file name that starts with a tilde (~) is not
 1127 available.
 1128 </P>
 1129 <P>
 1130 The ability to save and reload files in <b>pcretest</b> is intended for testing
 1131 and experimentation. It is not intended for production use because only a
 1132 single pattern can be written to a file. Furthermore, there is no facility for
 1133 supplying custom character tables for use with a reloaded pattern. If the
 1134 original pattern was compiled with custom tables, an attempt to match a subject
 1135 string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
 1136 Finally, if you attempt to load a file that is not in the correct format, the
 1137 result is undefined.
 1138 </P>
 1139 <br><a name="SEC15" href="#TOC1">SEE ALSO</a><br>
 1140 <P>
 1141 <b>pcre</b>(3), <b>pcre16</b>(3), <b>pcre32</b>(3), <b>pcreapi</b>(3),
 1142 <b>pcrecallout</b>(3),
 1143 <b>pcrejit</b>, <b>pcrematching</b>(3), <b>pcrepartial</b>(d),
 1144 <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3).
 1145 </P>
 1146 <br><a name="SEC16" href="#TOC1">AUTHOR</a><br>
 1147 <P>
 1148 Philip Hazel
 1149 <br>
 1150 University Computing Service
 1151 <br>
 1152 Cambridge CB2 3QH, England.
 1153 <br>
 1154 </P>
 1155 <br><a name="SEC17" href="#TOC1">REVISION</a><br>
 1156 <P>
 1157 Last updated: 23 February 2017
 1158 <br>
 1159 Copyright &copy; 1997-2017 University of Cambridge.
 1160 <br>
 1161 <p>
 1162 Return to the <a href="index.html">PCRE index page</a>.
 1163 </p>