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+<html>
+<head>
+<title>pcretest specification</title>
+</head>
+<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
+<h1>pcretest man page</h1>
+<p>
+Return to the <a href="index.html">PCRE index page</a>.
+</p>
+<p>
+This page is part of the PCRE HTML documentation. It was generated automatically
+from the original man page. If there is any nonsense in it, please consult the
+man page, in case the conversion went wrong.
+<br>
+<ul>
+<li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
+<li><a name="TOC2" href="#SEC2">OPTIONS</a>
+<li><a name="TOC3" href="#SEC3">DESCRIPTION</a>
+<li><a name="TOC4" href="#SEC4">PATTERN MODIFIERS</a>
+<li><a name="TOC5" href="#SEC5">DATA LINES</a>
+<li><a name="TOC6" href="#SEC6">THE ALTERNATIVE MATCHING FUNCTION</a>
+<li><a name="TOC7" href="#SEC7">DEFAULT OUTPUT FROM PCRETEST</a>
+<li><a name="TOC8" href="#SEC8">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a>
+<li><a name="TOC9" href="#SEC9">RESTARTING AFTER A PARTIAL MATCH</a>
+<li><a name="TOC10" href="#SEC10">CALLOUTS</a>
+<li><a name="TOC11" href="#SEC11">NON-PRINTING CHARACTERS</a>
+<li><a name="TOC12" href="#SEC12">SAVING AND RELOADING COMPILED PATTERNS</a>
+<li><a name="TOC13" href="#SEC13">SEE ALSO</a>
+<li><a name="TOC14" href="#SEC14">AUTHOR</a>
+<li><a name="TOC15" href="#SEC15">REVISION</a>
+</ul>
+<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
+<P>
+<b>pcretest [options] [source] [destination]</b>
+<br>
+<br>
+<b>pcretest</b> was written as a test program for the PCRE regular expression
+library itself, but it can also be used for experimenting with regular
+expressions. This document describes the features of the test program; for
+details of the regular expressions themselves, see the
+<a href="pcrepattern.html"><b>pcrepattern</b></a>
+documentation. For details of the PCRE library function calls and their
+options, see the
+<a href="pcreapi.html"><b>pcreapi</b></a>
+documentation.
+</P>
+<br><a name="SEC2" href="#TOC1">OPTIONS</a><br>
+<P>
+<b>-b</b>
+Behave as if each regex has the <b>/B</b> (show bytecode) modifier; the internal
+form is output after compilation.
+</P>
+<P>
+<b>-C</b>
+Output the version number of the PCRE library, and all available information
+about the optional features that are included, and then exit.
+</P>
+<P>
+<b>-d</b>
+Behave as if each regex has the <b>/D</b> (debug) modifier; the internal
+form and information about the compiled pattern is output after compilation;
+<b>-d</b> is equivalent to <b>-b -i</b>.
+</P>
+<P>
+<b>-dfa</b>
+Behave as if each data line contains the \D escape sequence; this causes the
+alternative matching function, <b>pcre_dfa_exec()</b>, to be used instead of the
+standard <b>pcre_exec()</b> function (more detail is given below).
+</P>
+<P>
+<b>-help</b>
+Output a brief summary these options and then exit.
+</P>
+<P>
+<b>-i</b>
+Behave as if each regex has the <b>/I</b> modifier; information about the
+compiled pattern is given after compilation.
+</P>
+<P>
+<b>-m</b>
+Output the size of each compiled pattern after it has been compiled. This is
+equivalent to adding <b>/M</b> to each regular expression. For compatibility
+with earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>.
+</P>
+<P>
+<b>-o</b> <i>osize</i>
+Set the number of elements in the output vector that is used when calling
+<b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> to be <i>osize</i>. The default value
+is 45, which is enough for 14 capturing subexpressions for <b>pcre_exec()</b> or
+22 different matches for <b>pcre_dfa_exec()</b>. The vector size can be
+changed for individual matching calls by including \O in the data line (see
+below).
+</P>
+<P>
+<b>-p</b>
+Behave as if each regex has the <b>/P</b> modifier; the POSIX wrapper API is
+used to call PCRE. None of the other options has any effect when <b>-p</b> is
+set.
+</P>
+<P>
+<b>-q</b>
+Do not output the version number of <b>pcretest</b> at the start of execution.
+</P>
+<P>
+<b>-S</b> <i>size</i>
+On Unix-like systems, set the size of the runtime stack to <i>size</i>
+megabytes.
+</P>
+<P>
+<b>-t</b>
+Run each compile, study, and match many times with a timer, and output
+resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with
+<b>-t</b>, because you will then get the size output a zillion times, and the
+timing will be distorted. You can control the number of iterations that are
+used for timing by following <b>-t</b> with a number (as a separate item on the
+command line). For example, "-t 1000" would iterate 1000 times. The default is
+to iterate 500000 times.
+</P>
+<P>
+<b>-tm</b>
+This is like <b>-t</b> except that it times only the matching phase, not the
+compile or study phases.
+</P>
+<br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br>
+<P>
+If <b>pcretest</b> is given two filename arguments, it reads from the first and
+writes to the second. If it is given only one filename argument, it reads from
+that file and writes to stdout. Otherwise, it reads from stdin and writes to
+stdout, and prompts for each line of input, using "re>" to prompt for regular
+expressions, and "data>" to prompt for data lines.
+</P>
+<P>
+When <b>pcretest</b> is built, a configuration option can specify that it should
+be linked with the <b>libreadline</b> library. When this is done, if the input
+is from a terminal, it is read using the <b>readline()</b> function. This
+provides line-editing and history facilities. The output from the <b>-help</b>
+option states whether or not <b>readline()</b> will be used.
+</P>
+<P>
+The program handles any number of sets of input on a single input file. Each
+set starts with a regular expression, and continues with any number of data
+lines to be matched against the pattern.
+</P>
+<P>
+Each data line is matched separately and independently. If you want to do
+multi-line matches, you have to use the \n escape sequence (or \r or \r\n,
+etc., depending on the newline setting) in a single line of input to encode the
+newline sequences. There is no limit on the length of data lines; the input
+buffer is automatically extended if it is too small.
+</P>
+<P>
+An empty line signals the end of the data lines, at which point a new regular
+expression is read. The regular expressions are given enclosed in any
+non-alphanumeric delimiters other than backslash, for example:
+<pre>
+ /(a|bc)x+yz/
+</pre>
+White space before the initial delimiter is ignored. A regular expression may
+be continued over several input lines, in which case the newline characters are
+included within it. It is possible to include the delimiter within the pattern
+by escaping it, for example
+<pre>
+ /abc\/def/
+</pre>
+If you do so, the escape and the delimiter form part of the pattern, but since
+delimiters are always non-alphanumeric, this does not affect its interpretation.
+If the terminating delimiter is immediately followed by a backslash, for
+example,
+<pre>
+ /abc/\
+</pre>
+then a backslash is added to the end of the pattern. This is done to provide a
+way of testing the error condition that arises if a pattern finishes with a
+backslash, because
+<pre>
+ /abc\/
+</pre>
+is interpreted as the first line of a pattern that starts with "abc/", causing
+pcretest to read the next line as a continuation of the regular expression.
+</P>
+<br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br>
+<P>
+A pattern may be followed by any number of modifiers, which are mostly single
+characters. Following Perl usage, these are referred to below as, for example,
+"the <b>/i</b> modifier", even though the delimiter of the pattern need not
+always be a slash, and no slash is used when writing modifiers. Whitespace may
+appear between the final pattern delimiter and the first modifier, and between
+the modifiers themselves.
+</P>
+<P>
+The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
+PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
+<b>pcre_compile()</b> is called. These four modifier letters have the same
+effect as they do in Perl. For example:
+<pre>
+ /caseless/i
+</pre>
+The following table shows additional modifiers for setting PCRE options that do
+not correspond to anything in Perl:
+<pre>
+ <b>/A</b> PCRE_ANCHORED
+ <b>/C</b> PCRE_AUTO_CALLOUT
+ <b>/E</b> PCRE_DOLLAR_ENDONLY
+ <b>/f</b> PCRE_FIRSTLINE
+ <b>/J</b> PCRE_DUPNAMES
+ <b>/N</b> PCRE_NO_AUTO_CAPTURE
+ <b>/U</b> PCRE_UNGREEDY
+ <b>/X</b> PCRE_EXTRA
+ <b>/<JS></b> PCRE_JAVASCRIPT_COMPAT
+ <b>/<cr></b> PCRE_NEWLINE_CR
+ <b>/<lf></b> PCRE_NEWLINE_LF
+ <b>/<crlf></b> PCRE_NEWLINE_CRLF
+ <b>/<anycrlf></b> PCRE_NEWLINE_ANYCRLF
+ <b>/<any></b> PCRE_NEWLINE_ANY
+ <b>/<bsr_anycrlf></b> PCRE_BSR_ANYCRLF
+ <b>/<bsr_unicode></b> PCRE_BSR_UNICODE
+</pre>
+Those specifying line ending sequences are literal strings as shown, but the
+letters can be in either case. This example sets multiline matching with CRLF
+as the line ending sequence:
+<pre>
+ /^abc/m<crlf>
+</pre>
+Details of the meanings of these PCRE options are given in the
+<a href="pcreapi.html"><b>pcreapi</b></a>
+documentation.
+</P>
+<br><b>
+Finding all matches in a string
+</b><br>
+<P>
+Searching for all possible matches within each subject string can be requested
+by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
+again to search the remainder of the subject string. The difference between
+<b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
+<b>pcre_exec()</b> to start searching at a new point within the entire string
+(which is in effect what Perl does), whereas the latter passes over a shortened
+substring. This makes a difference to the matching process if the pattern
+begins with a lookbehind assertion (including \b or \B).
+</P>
+<P>
+If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an
+empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
+flags set in order to search for another, non-empty, match at the same point.
+If this second match fails, the start offset is advanced by one, and the normal
+match is retried. This imitates the way Perl handles such cases when using the
+<b>/g</b> modifier or the <b>split()</b> function.
+</P>
+<br><b>
+Other modifiers
+</b><br>
+<P>
+There are yet more modifiers for controlling the way <b>pcretest</b>
+operates.
+</P>
+<P>
+The <b>/+</b> modifier requests that as well as outputting the substring that
+matched the entire pattern, pcretest should in addition output the remainder of
+the subject string. This is useful for tests where the subject contains
+multiple copies of the same substring.
+</P>
+<P>
+The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
+output a representation of the compiled byte code after compilation. Normally
+this information contains length and offset values; however, if <b>/Z</b> is
+also present, this data is replaced by spaces. This is a special feature for
+use in the automatic test scripts; it ensures that the same output is generated
+for different internal link sizes.
+</P>
+<P>
+The <b>/L</b> modifier must be followed directly by the name of a locale, for
+example,
+<pre>
+ /pattern/Lfr_FR
+</pre>
+For this reason, it must be the last modifier. The given locale is set,
+<b>pcre_maketables()</b> is called to build a set of character tables for the
+locale, and this is then passed to <b>pcre_compile()</b> when compiling the
+regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables
+pointer; that is, <b>/L</b> applies only to the expression on which it appears.
+</P>
+<P>
+The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
+compiled pattern (whether it is anchored, has a fixed first character, and
+so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
+pattern. If the pattern is studied, the results of that are also output.
+</P>
+<P>
+The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
+<b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
+</P>
+<P>
+The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
+fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
+facility is for testing the feature in PCRE that allows it to execute patterns
+that were compiled on a host with a different endianness. This feature is not
+available when the POSIX interface to PCRE is being used, that is, when the
+<b>/P</b> pattern modifier is specified. See also the section about saving and
+reloading compiled patterns below.
+</P>
+<P>
+The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the
+expression has been compiled, and the results used when the expression is
+matched.
+</P>
+<P>
+The <b>/M</b> modifier causes the size of memory block used to hold the compiled
+pattern to be output.
+</P>
+<P>
+The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
+API rather than its native API. When this is done, all other modifiers except
+<b>/i</b>, <b>/m</b>, and <b>/+</b> are ignored. REG_ICASE is set if <b>/i</b> is
+present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions
+force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
+</P>
+<P>
+The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8
+option set. This turns on support for UTF-8 character handling in PCRE,
+provided that it was compiled with this support enabled. This modifier also
+causes any non-printing characters in output strings to be printed using the
+\x{hh...} notation if they are valid UTF-8 sequences.
+</P>
+<P>
+If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to
+call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the
+checking of the string for UTF-8 validity.
+</P>
+<br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
+<P>
+Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
+whitespace is removed, and it is then scanned for \ escapes. Some of these are
+pretty esoteric features, intended for checking out some of the more
+complicated features of PCRE. If you are just testing "ordinary" regular
+expressions, you probably don't need any of these. The following escapes are
+recognized:
+<pre>
+ \a alarm (BEL, \x07)
+ \b backspace (\x08)
+ \e escape (\x27)
+ \f formfeed (\x0c)
+ \n newline (\x0a)
+ \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
+ \r carriage return (\x0d)
+ \t tab (\x09)
+ \v vertical tab (\x0b)
+ \nnn octal character (up to 3 octal digits)
+ \xhh hexadecimal character (up to 2 hex digits)
+ \x{hh...} hexadecimal character, any number of digits in UTF-8 mode
+ \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32)
+ \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
+ ated by next non alphanumeric character)
+ \C+ show the current captured substrings at callout time
+ \C- do not supply a callout function
+ \C!n return 1 instead of 0 when callout number n is reached
+ \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
+ \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
+ \D use the <b>pcre_dfa_exec()</b> match function
+ \F only shortest match for <b>pcre_dfa_exec()</b>
+ \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32)
+ \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin-
+ ated by next non-alphanumeric character)
+ \L call pcre_get_substringlist() after a successful match
+ \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
+ \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
+ \P pass the PCRE_PARTIAL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
+ \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
+ \S output details of memory get/free calls during matching
+ \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \>dd start the match at offset dd (any number of digits);
+ this sets the <i>startoffset</i> argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \<cr> pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \<lf> pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \<crlf> pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+ \<any> pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
+</pre>
+The escapes that specify line ending sequences are literal strings, exactly as
+shown. No more than one newline setting should be present in any data line.
+</P>
+<P>
+A backslash followed by anything else just escapes the anything else. If
+the very last character is a backslash, it is ignored. This gives a way of
+passing an empty line as data, since a real empty line terminates the data
+input.
+</P>
+<P>
+If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
+different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
+fields of the <b>pcre_extra</b> data structure, until it finds the minimum
+numbers for each parameter that allow <b>pcre_exec()</b> to complete. The
+<i>match_limit</i> number is a measure of the amount of backtracking that takes
+place, and checking it out can be instructive. For most simple matches, the
+number is quite small, but for patterns with very large numbers of matching
+possibilities, it can become large very quickly with increasing length of
+subject string. The <i>match_limit_recursion</i> number is a measure of how much
+stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed
+to complete the match attempt.
+</P>
+<P>
+When \O is used, the value specified may be higher or lower than the size set
+by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
+the call of <b>pcre_exec()</b> for the line in which it appears.
+</P>
+<P>
+If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
+API to be used, the only option-setting sequences that have any effect are \B
+and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to
+<b>regexec()</b>.
+</P>
+<P>
+The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
+of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
+any number of hexadecimal digits inside the braces. The result is from one to
+six bytes, encoded according to the original UTF-8 rules of RFC 2279. This
+allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are
+valid Unicode code points, or indeed valid UTF-8 characters according to the
+later rules in RFC 3629.
+</P>
+<br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
+<P>
+By default, <b>pcretest</b> uses the standard PCRE matching function,
+<b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
+alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
+different way, and has some restrictions. The differences between the two
+functions are described in the
+<a href="pcrematching.html"><b>pcrematching</b></a>
+documentation.
+</P>
+<P>
+If a data line contains the \D escape sequence, or if the command line
+contains the <b>-dfa</b> option, the alternative matching function is called.
+This function finds all possible matches at a given point. If, however, the \F
+escape sequence is present in the data line, it stops after the first match is
+found. This is always the shortest possible match.
+</P>
+<br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
+<P>
+This section describes the output when the normal matching function,
+<b>pcre_exec()</b>, is being used.
+</P>
+<P>
+When a match succeeds, pcretest outputs the list of captured substrings that
+<b>pcre_exec()</b> returns, starting with number 0 for the string that matched
+the whole pattern. Otherwise, it outputs "No match" or "Partial match"
+when <b>pcre_exec()</b> returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PARTIAL,
+respectively, and otherwise the PCRE negative error number. Here is an example
+of an interactive <b>pcretest</b> run.
+<pre>
+ $ pcretest
+ PCRE version 7.0 30-Nov-2006
+
+ re> /^abc(\d+)/
+ data> abc123
+ 0: abc123
+ 1: 123
+ data> xyz
+ No match
+</pre>
+Note that unset capturing substrings that are not followed by one that is set
+are not returned by <b>pcre_exec()</b>, and are not shown by <b>pcretest</b>. In
+the following example, there are two capturing substrings, but when the first
+data line is matched, the second, unset substring is not shown. An "internal"
+unset substring is shown as "<unset>", as for the second data line.
+<pre>
+ re> /(a)|(b)/
+ data> a
+ 0: a
+ 1: a
+ data> b
+ 0: b
+ 1: <unset>
+ 2: b
+</pre>
+If the strings contain any non-printing characters, they are output as \0x
+escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
+pattern. See below for the definition of non-printing characters. If the
+pattern has the <b>/+</b> modifier, the output for substring 0 is followed by
+the the rest of the subject string, identified by "0+" like this:
+<pre>
+ re> /cat/+
+ data> cataract
+ 0: cat
+ 0+ aract
+</pre>
+If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
+matching attempts are output in sequence, like this:
+<pre>
+ re> /\Bi(\w\w)/g
+ data> Mississippi
+ 0: iss
+ 1: ss
+ 0: iss
+ 1: ss
+ 0: ipp
+ 1: pp
+</pre>
+"No match" is output only if the first match attempt fails.
+</P>
+<P>
+If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
+data line that is successfully matched, the substrings extracted by the
+convenience functions are output with C, G, or L after the string number
+instead of a colon. This is in addition to the normal full list. The string
+length (that is, the return from the extraction function) is given in
+parentheses after each string for <b>\C</b> and <b>\G</b>.
+</P>
+<P>
+Note that whereas patterns can be continued over several lines (a plain ">"
+prompt is used for continuations), data lines may not. However newlines can be
+included in data by means of the \n escape (or \r, \r\n, etc., depending on
+the newline sequence setting).
+</P>
+<br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
+<P>
+When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
+means of the \D escape sequence or the <b>-dfa</b> command line option), the
+output consists of a list of all the matches that start at the first point in
+the subject where there is at least one match. For example:
+<pre>
+ re> /(tang|tangerine|tan)/
+ data> yellow tangerine\D
+ 0: tangerine
+ 1: tang
+ 2: tan
+</pre>
+(Using the normal matching function on this data finds only "tang".) The
+longest matching string is always given first (and numbered zero).
+</P>
+<P>
+If <b>/g</b> is present on the pattern, the search for further matches resumes
+at the end of the longest match. For example:
+<pre>
+ re> /(tang|tangerine|tan)/g
+ data> yellow tangerine and tangy sultana\D
+ 0: tangerine
+ 1: tang
+ 2: tan
+ 0: tang
+ 1: tan
+ 0: tan
+</pre>
+Since the matching function does not support substring capture, the escape
+sequences that are concerned with captured substrings are not relevant.
+</P>
+<br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
+<P>
+When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
+indicating that the subject partially matched the pattern, you can restart the
+match with additional subject data by means of the \R escape sequence. For
+example:
+<pre>
+ re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
+ data> 23ja\P\D
+ Partial match: 23ja
+ data> n05\R\D
+ 0: n05
+</pre>
+For further information about partial matching, see the
+<a href="pcrepartial.html"><b>pcrepartial</b></a>
+documentation.
+</P>
+<br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
+<P>
+If the pattern contains any callout requests, <b>pcretest</b>'s callout function
+is called during matching. This works with both matching functions. By default,
+the called function displays the callout number, the start and current
+positions in the text at the callout time, and the next pattern item to be
+tested. For example, the output
+<pre>
+ --->pqrabcdef
+ 0 ^ ^ \d
+</pre>
+indicates that callout number 0 occurred for a match attempt starting at the
+fourth character of the subject string, when the pointer was at the seventh
+character of the data, and when the next pattern item was \d. Just one
+circumflex is output if the start and current positions are the same.
+</P>
+<P>
+Callouts numbered 255 are assumed to be automatic callouts, inserted as a
+result of the <b>/C</b> pattern modifier. In this case, instead of showing the
+callout number, the offset in the pattern, preceded by a plus, is output. For
+example:
+<pre>
+ re> /\d?[A-E]\*/C
+ data> E*
+ --->E*
+ +0 ^ \d?
+ +3 ^ [A-E]
+ +8 ^^ \*
+ +10 ^ ^
+ 0: E*
+</pre>
+The callout function in <b>pcretest</b> returns zero (carry on matching) by
+default, but you can use a \C item in a data line (as described above) to
+change this.
+</P>
+<P>
+Inserting callouts can be helpful when using <b>pcretest</b> to check
+complicated regular expressions. For further information about callouts, see
+the
+<a href="pcrecallout.html"><b>pcrecallout</b></a>
+documentation.
+</P>
+<br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
+<P>
+When <b>pcretest</b> is outputting text in the compiled version of a pattern,
+bytes other than 32-126 are always treated as non-printing characters are are
+therefore shown as hex escapes.
+</P>
+<P>
+When <b>pcretest</b> is outputting text that is a matched part of a subject
+string, it behaves in the same way, unless a different locale has been set for
+the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
+function to distinguish printing and non-printing characters.
+</P>
+<br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
+<P>
+The facilities described in this section are not available when the POSIX
+inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
+specified.
+</P>
+<P>
+When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
+compiled pattern to a file, by following the modifiers with > and a file name.
+For example:
+<pre>
+ /pattern/im >/some/file
+</pre>
+See the
+<a href="pcreprecompile.html"><b>pcreprecompile</b></a>
+documentation for a discussion about saving and re-using compiled patterns.
+</P>
+<P>
+The data that is written is binary. The first eight bytes are the length of the
+compiled pattern data followed by the length of the optional study data, each
+written as four bytes in big-endian order (most significant byte first). If
+there is no study data (either the pattern was not studied, or studying did not
+return any data), the second length is zero. The lengths are followed by an
+exact copy of the compiled pattern. If there is additional study data, this
+follows immediately after the compiled pattern. After writing the file,
+<b>pcretest</b> expects to read a new pattern.
+</P>
+<P>
+A saved pattern can be reloaded into <b>pcretest</b> by specifing < and a file
+name instead of a pattern. The name of the file must not contain a < character,
+as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by <
+characters.
+For example:
+<pre>
+ re> </some/file
+ Compiled regex loaded from /some/file
+ No study data
+</pre>
+When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in
+the usual way.
+</P>
+<P>
+You can copy a file written by <b>pcretest</b> to a different host and reload it
+there, even if the new host has opposite endianness to the one on which the
+pattern was compiled. For example, you can compile on an i86 machine and run on
+a SPARC machine.
+</P>
+<P>
+File names for saving and reloading can be absolute or relative, but note that
+the shell facility of expanding a file name that starts with a tilde (~) is not
+available.
+</P>
+<P>
+The ability to save and reload files in <b>pcretest</b> is intended for testing
+and experimentation. It is not intended for production use because only a
+single pattern can be written to a file. Furthermore, there is no facility for
+supplying custom character tables for use with a reloaded pattern. If the
+original pattern was compiled with custom tables, an attempt to match a subject
+string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
+Finally, if you attempt to load a file that is not in the correct format, the
+result is undefined.
+</P>
+<br><a name="SEC13" href="#TOC1">SEE ALSO</a><br>
+<P>
+<b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3),
+<b>pcrepartial</b>(d), <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3).
+</P>
+<br><a name="SEC14" href="#TOC1">AUTHOR</a><br>
+<P>
+Philip Hazel
+<br>
+University Computing Service
+<br>
+Cambridge CB2 3QH, England.
+<br>
+</P>
+<br><a name="SEC15" href="#TOC1">REVISION</a><br>
+<P>
+Last updated: 12 April 2008
+<br>
+Copyright © 1997-2008 University of Cambridge.
+<br>
+<p>
+Return to the <a href="index.html">PCRE index page</a>.
+</p>