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 <html>
 <head>
 <title>pcrecpp specification</title>
 </head>
 <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
 <h1>pcrecpp 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 OF C++ WRAPPER</a>
 <li><a name="TOC2" href="#SEC2">DESCRIPTION</a>
 <li><a name="TOC3" href="#SEC3">MATCHING INTERFACE</a>
 <li><a name="TOC4" href="#SEC4">QUOTING METACHARACTERS</a>
 <li><a name="TOC5" href="#SEC5">PARTIAL MATCHES</a>
 <li><a name="TOC6" href="#SEC6">UTF-8 AND THE MATCHING INTERFACE</a>
 <li><a name="TOC7" href="#SEC7">PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE</a>
 <li><a name="TOC8" href="#SEC8">SCANNING TEXT INCREMENTALLY</a>
 <li><a name="TOC9" href="#SEC9">PARSING HEX/OCTAL/C-RADIX NUMBERS</a>
 <li><a name="TOC10" href="#SEC10">REPLACING PARTS OF STRINGS</a>
 <li><a name="TOC11" href="#SEC11">AUTHOR</a>
 <li><a name="TOC12" href="#SEC12">REVISION</a>
 </ul>
 <br><a name="SEC1" href="#TOC1">SYNOPSIS OF C++ WRAPPER</a><br>
 <P>
 <b>#include &#60;pcrecpp.h&#62;</b>
 </P>
 <br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
 <P>
 The C++ wrapper for PCRE was provided by Google Inc. Some additional
 functionality was added by Giuseppe Maxia. This brief man page was constructed
 from the notes in the <i>pcrecpp.h</i> file, which should be consulted for
 further details. Note that the C++ wrapper supports only the original 8-bit
 PCRE library. There is no 16-bit or 32-bit support at present.
 </P>
 <br><a name="SEC3" href="#TOC1">MATCHING INTERFACE</a><br>
 <P>
 The "FullMatch" operation checks that supplied text matches a supplied pattern
 exactly. If pointer arguments are supplied, it copies matched sub-strings that
 match sub-patterns into them.
 <pre>
   Example: successful match
      pcrecpp::RE re("h.*o");
      re.FullMatch("hello");

   Example: unsuccessful match (requires full match):
      pcrecpp::RE re("e");
      !re.FullMatch("hello");

   Example: creating a temporary RE object:
      pcrecpp::RE("h.*o").FullMatch("hello");
 </pre>
 You can pass in a "const char*" or a "string" for "text". The examples below
 tend to use a const char*. You can, as in the different examples above, store
 the RE object explicitly in a variable or use a temporary RE object. The
 examples below use one mode or the other arbitrarily. Either could correctly be
 used for any of these examples.
 </P>
 <P>
 You must supply extra pointer arguments to extract matched subpieces.
 <pre>
   Example: extracts "ruby" into "s" and 1234 into "i"
      int i;
      string s;
      pcrecpp::RE re("(\\w+):(\\d+)");
      re.FullMatch("ruby:1234", &s, &i);

   Example: does not try to extract any extra sub-patterns
      re.FullMatch("ruby:1234", &s);

   Example: does not try to extract into NULL
      re.FullMatch("ruby:1234", NULL, &i);

   Example: integer overflow causes failure
      !re.FullMatch("ruby:1234567891234", NULL, &i);

   Example: fails because there aren't enough sub-patterns:
      !pcrecpp::RE("\\w+:\\d+").FullMatch("ruby:1234", &s);

   Example: fails because string cannot be stored in integer
      !pcrecpp::RE("(.*)").FullMatch("ruby", &i);
 </pre>
 The provided pointer arguments can be pointers to any scalar numeric
 type, or one of:
 <pre>
    string        (matched piece is copied to string)
    StringPiece   (StringPiece is mutated to point to matched piece)
    T             (where "bool T::ParseFrom(const char*, int)" exists)
    NULL          (the corresponding matched sub-pattern is not copied)
 </pre>
 The function returns true iff all of the following conditions are satisfied:
 <pre>
   a. "text" matches "pattern" exactly;

   b. The number of matched sub-patterns is &#62;= number of supplied
      pointers;

   c. The "i"th argument has a suitable type for holding the
      string captured as the "i"th sub-pattern. If you pass in
      void * NULL for the "i"th argument, or a non-void * NULL
      of the correct type, or pass fewer arguments than the
      number of sub-patterns, "i"th captured sub-pattern is
      ignored.
 </pre>
 CAVEAT: An optional sub-pattern that does not exist in the matched
 string is assigned the empty string. Therefore, the following will
 return false (because the empty string is not a valid number):
 <pre>
    int number;
    pcrecpp::RE::FullMatch("abc", "[a-z]+(\\d+)?", &number);
 </pre>
 The matching interface supports at most 16 arguments per call.
 If you need more, consider using the more general interface
 <b>pcrecpp::RE::DoMatch</b>. See <b>pcrecpp.h</b> for the signature for
 <b>DoMatch</b>.
 </P>
 <P>
 NOTE: Do not use <b>no_arg</b>, which is used internally to mark the end of a
 list of optional arguments, as a placeholder for missing arguments, as this can
 lead to segfaults.
 </P>
 <br><a name="SEC4" href="#TOC1">QUOTING METACHARACTERS</a><br>
 <P>
 You can use the "QuoteMeta" operation to insert backslashes before all
 potentially meaningful characters in a string. The returned string, used as a
 regular expression, will exactly match the original string.
 <pre>
   Example:
      string quoted = RE::QuoteMeta(unquoted);
 </pre>
 Note that it's legal to escape a character even if it has no special meaning in
 a regular expression -- so this function does that. (This also makes it
 identical to the perl function of the same name; see "perldoc -f quotemeta".)
 For example, "1.5-2.0?" becomes "1\.5\-2\.0\?".
 </P>
 <br><a name="SEC5" href="#TOC1">PARTIAL MATCHES</a><br>
 <P>
 You can use the "PartialMatch" operation when you want the pattern
 to match any substring of the text.
 <pre>
   Example: simple search for a string:
      pcrecpp::RE("ell").PartialMatch("hello");

   Example: find first number in a string:
      int number;
      pcrecpp::RE re("(\\d+)");
      re.PartialMatch("x*100 + 20", &number);
      assert(number == 100);
 </PRE>
 </P>
 <br><a name="SEC6" href="#TOC1">UTF-8 AND THE MATCHING INTERFACE</a><br>
 <P>
 By default, pattern and text are plain text, one byte per character. The UTF8
 flag, passed to the constructor, causes both pattern and string to be treated
 as UTF-8 text, still a byte stream but potentially multiple bytes per
 character. In practice, the text is likelier to be UTF-8 than the pattern, but
 the match returned may depend on the UTF8 flag, so always use it when matching
 UTF8 text. For example, "." will match one byte normally but with UTF8 set may
 match up to three bytes of a multi-byte character.
 <pre>
   Example:
      pcrecpp::RE_Options options;
      options.set_utf8();
      pcrecpp::RE re(utf8_pattern, options);
      re.FullMatch(utf8_string);

   Example: using the convenience function UTF8():
      pcrecpp::RE re(utf8_pattern, pcrecpp::UTF8());
      re.FullMatch(utf8_string);
 </pre>
 NOTE: The UTF8 flag is ignored if pcre was not configured with the
 <pre>
       --enable-utf8 flag.
 </PRE>
 </P>
 <br><a name="SEC7" href="#TOC1">PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE</a><br>
 <P>
 PCRE defines some modifiers to change the behavior of the regular expression
 engine. The C++ wrapper defines an auxiliary class, RE_Options, as a vehicle to
 pass such modifiers to a RE class. Currently, the following modifiers are
 supported:
 <pre>
    modifier              description               Perl corresponding

    PCRE_CASELESS         case insensitive match      /i
    PCRE_MULTILINE        multiple lines match        /m
    PCRE_DOTALL           dot matches newlines        /s
    PCRE_DOLLAR_ENDONLY   $ matches only at end       N/A
    PCRE_EXTRA            strict escape parsing       N/A
    PCRE_EXTENDED         ignore white spaces         /x
    PCRE_UTF8             handles UTF8 chars          built-in
    PCRE_UNGREEDY         reverses * and *?           N/A
    PCRE_NO_AUTO_CAPTURE  disables capturing parens   N/A (*)
 </pre>
 (*) Both Perl and PCRE allow non capturing parentheses by means of the
 "?:" modifier within the pattern itself. e.g. (?:ab|cd) does not
 capture, while (ab|cd) does.
 </P>
 <P>
 For a full account on how each modifier works, please check the
 PCRE API reference page.
 </P>
 <P>
 For each modifier, there are two member functions whose name is made
 out of the modifier in lowercase, without the "PCRE_" prefix. For
 instance, PCRE_CASELESS is handled by
 <pre>
   bool caseless()
 </pre>
 which returns true if the modifier is set, and
 <pre>
   RE_Options & set_caseless(bool)
 </pre>
 which sets or unsets the modifier. Moreover, PCRE_EXTRA_MATCH_LIMIT can be
 accessed through the <b>set_match_limit()</b> and <b>match_limit()</b> member
 functions. Setting <i>match_limit</i> to a non-zero value will limit the
 execution of pcre to keep it from doing bad things like blowing the stack or
 taking an eternity to return a result. A value of 5000 is good enough to stop
 stack blowup in a 2MB thread stack. Setting <i>match_limit</i> to zero disables
 match limiting. Alternatively, you can call <b>match_limit_recursion()</b>
 which uses PCRE_EXTRA_MATCH_LIMIT_RECURSION to limit how much PCRE
 recurses. <b>match_limit()</b> limits the number of matches PCRE does;
 <b>match_limit_recursion()</b> limits the depth of internal recursion, and
 therefore the amount of stack that is used.
 </P>
 <P>
 Normally, to pass one or more modifiers to a RE class, you declare
 a <i>RE_Options</i> object, set the appropriate options, and pass this
 object to a RE constructor. Example:
 <pre>
    RE_Options opt;
    opt.set_caseless(true);
    if (RE("HELLO", opt).PartialMatch("hello world")) ...
 </pre>
 RE_options has two constructors. The default constructor takes no arguments and
 creates a set of flags that are off by default. The optional parameter
 <i>option_flags</i> is to facilitate transfer of legacy code from C programs.
 This lets you do
 <pre>
    RE(pattern,
      RE_Options(PCRE_CASELESS|PCRE_MULTILINE)).PartialMatch(str);
 </pre>
 However, new code is better off doing
 <pre>
    RE(pattern,
      RE_Options().set_caseless(true).set_multiline(true))
        .PartialMatch(str);
 </pre>
 If you are going to pass one of the most used modifiers, there are some
 convenience functions that return a RE_Options class with the
 appropriate modifier already set: <b>CASELESS()</b>, <b>UTF8()</b>,
 <b>MULTILINE()</b>, <b>DOTALL</b>(), and <b>EXTENDED()</b>.
 </P>
 <P>
 If you need to set several options at once, and you don't want to go through
 the pains of declaring a RE_Options object and setting several options, there
 is a parallel method that give you such ability on the fly. You can concatenate
 several <b>set_xxxxx()</b> member functions, since each of them returns a
 reference to its class object. For example, to pass PCRE_CASELESS,
 PCRE_EXTENDED, and PCRE_MULTILINE to a RE with one statement, you may write:
 <pre>
    RE(" ^ xyz \\s+ .* blah$",
      RE_Options()
        .set_caseless(true)
        .set_extended(true)
        .set_multiline(true)).PartialMatch(sometext);

 </PRE>
 </P>
 <br><a name="SEC8" href="#TOC1">SCANNING TEXT INCREMENTALLY</a><br>
 <P>
 The "Consume" operation may be useful if you want to repeatedly
 match regular expressions at the front of a string and skip over
 them as they match. This requires use of the "StringPiece" type,
 which represents a sub-range of a real string. Like RE, StringPiece
 is defined in the pcrecpp namespace.
 <pre>
   Example: read lines of the form "var = value" from a string.
      string contents = ...;                 // Fill string somehow
      pcrecpp::StringPiece input(contents);  // Wrap in a StringPiece

      string var;
      int value;
      pcrecpp::RE re("(\\w+) = (\\d+)\n");
      while (re.Consume(&input, &var, &value)) {
        ...;
      }
 </pre>
 Each successful call to "Consume" will set "var/value", and also
 advance "input" so it points past the matched text.
 </P>
 <P>
 The "FindAndConsume" operation is similar to "Consume" but does not
 anchor your match at the beginning of the string. For example, you
 could extract all words from a string by repeatedly calling
 <pre>
   pcrecpp::RE("(\\w+)").FindAndConsume(&input, &word)
 </PRE>
 </P>
 <br><a name="SEC9" href="#TOC1">PARSING HEX/OCTAL/C-RADIX NUMBERS</a><br>
 <P>
 By default, if you pass a pointer to a numeric value, the
 corresponding text is interpreted as a base-10 number. You can
 instead wrap the pointer with a call to one of the operators Hex(),
 Octal(), or CRadix() to interpret the text in another base. The
 CRadix operator interprets C-style "0" (base-8) and "0x" (base-16)
 prefixes, but defaults to base-10.
 <pre>
   Example:
     int a, b, c, d;
     pcrecpp::RE re("(.*) (.*) (.*) (.*)");
     re.FullMatch("100 40 0100 0x40",
                  pcrecpp::Octal(&a), pcrecpp::Hex(&b),
                  pcrecpp::CRadix(&c), pcrecpp::CRadix(&d));
 </pre>
 will leave 64 in a, b, c, and d.
 </P>
 <br><a name="SEC10" href="#TOC1">REPLACING PARTS OF STRINGS</a><br>
 <P>
 You can replace the first match of "pattern" in "str" with "rewrite".
 Within "rewrite", backslash-escaped digits (\1 to \9) can be
 used to insert text matching corresponding parenthesized group
 from the pattern. \0 in "rewrite" refers to the entire matching
 text. For example:
 <pre>
   string s = "yabba dabba doo";
   pcrecpp::RE("b+").Replace("d", &s);
 </pre>
 will leave "s" containing "yada dabba doo". The result is true if the pattern
 matches and a replacement occurs, false otherwise.
 </P>
 <P>
 <b>GlobalReplace</b> is like <b>Replace</b> except that it replaces all
 occurrences of the pattern in the string with the rewrite. Replacements are
 not subject to re-matching. For example:
 <pre>
   string s = "yabba dabba doo";
   pcrecpp::RE("b+").GlobalReplace("d", &s);
 </pre>
 will leave "s" containing "yada dada doo". It returns the number of
 replacements made.
 </P>
 <P>
 <b>Extract</b> is like <b>Replace</b>, except that if the pattern matches,
 "rewrite" is copied into "out" (an additional argument) with substitutions.
 The non-matching portions of "text" are ignored. Returns true iff a match
 occurred and the extraction happened successfully;  if no match occurs, the
 string is left unaffected.
 </P>
 <br><a name="SEC11" href="#TOC1">AUTHOR</a><br>
 <P>
 The C++ wrapper was contributed by Google Inc.
 <br>
 Copyright &copy; 2007 Google Inc.
 <br>
 </P>
 <br><a name="SEC12" href="#TOC1">REVISION</a><br>
 <P>
 Last updated: 08 January 2012
 <br>
 <p>
 Return to the <a href="index.html">PCRE index page</a>.
 </p>
	<html>
	<head>
	<title>pcrecpp specification</title>
	</head>
	<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
	<h1>pcrecpp 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 OF C++ WRAPPER</a>
	<li><a name="TOC2" href="#SEC2">DESCRIPTION</a>
	<li><a name="TOC3" href="#SEC3">MATCHING INTERFACE</a>
	<li><a name="TOC4" href="#SEC4">QUOTING METACHARACTERS</a>
	<li><a name="TOC5" href="#SEC5">PARTIAL MATCHES</a>
	<li><a name="TOC6" href="#SEC6">UTF-8 AND THE MATCHING INTERFACE</a>
	<li><a name="TOC7" href="#SEC7">PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE</a>
	<li><a name="TOC8" href="#SEC8">SCANNING TEXT INCREMENTALLY</a>
	<li><a name="TOC9" href="#SEC9">PARSING HEX/OCTAL/C-RADIX NUMBERS</a>
	<li><a name="TOC10" href="#SEC10">REPLACING PARTS OF STRINGS</a>
	<li><a name="TOC11" href="#SEC11">AUTHOR</a>
	<li><a name="TOC12" href="#SEC12">REVISION</a>
	</ul>
	<br><a name="SEC1" href="#TOC1">SYNOPSIS OF C++ WRAPPER</a><br>
	<P>
	<b>#include <pcrecpp.h></b>
	</P>
	<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
	<P>
	The C++ wrapper for PCRE was provided by Google Inc. Some additional
	functionality was added by Giuseppe Maxia. This brief man page was constructed
	from the notes in the <i>pcrecpp.h</i> file, which should be consulted for
	further details. Note that the C++ wrapper supports only the original 8-bit
	PCRE library. There is no 16-bit or 32-bit support at present.
	</P>
	<br><a name="SEC3" href="#TOC1">MATCHING INTERFACE</a><br>
	<P>
	The "FullMatch" operation checks that supplied text matches a supplied pattern
	exactly. If pointer arguments are supplied, it copies matched sub-strings that
	match sub-patterns into them.
	<pre>
	Example: successful match
	pcrecpp::RE re("h.*o");
	re.FullMatch("hello");

	Example: unsuccessful match (requires full match):
	pcrecpp::RE re("e");
	!re.FullMatch("hello");

	Example: creating a temporary RE object:
	pcrecpp::RE("h.*o").FullMatch("hello");
	</pre>
	You can pass in a "const char*" or a "string" for "text". The examples below
	tend to use a const char*. You can, as in the different examples above, store
	the RE object explicitly in a variable or use a temporary RE object. The
	examples below use one mode or the other arbitrarily. Either could correctly be
	used for any of these examples.
	</P>
	<P>
	You must supply extra pointer arguments to extract matched subpieces.
	<pre>
	Example: extracts "ruby" into "s" and 1234 into "i"
	int i;
	string s;
	pcrecpp::RE re("(\\w+):(\\d+)");
	re.FullMatch("ruby:1234", &s, &i);

	Example: does not try to extract any extra sub-patterns
	re.FullMatch("ruby:1234", &s);

	Example: does not try to extract into NULL
	re.FullMatch("ruby:1234", NULL, &i);

	Example: integer overflow causes failure
	!re.FullMatch("ruby:1234567891234", NULL, &i);

	Example: fails because there aren't enough sub-patterns:
	!pcrecpp::RE("\\w+:\\d+").FullMatch("ruby:1234", &s);

	Example: fails because string cannot be stored in integer
	!pcrecpp::RE("(.*)").FullMatch("ruby", &i);
	</pre>
	The provided pointer arguments can be pointers to any scalar numeric
	type, or one of:
	<pre>
	string (matched piece is copied to string)
	StringPiece (StringPiece is mutated to point to matched piece)
	T (where "bool T::ParseFrom(const char*, int)" exists)
	NULL (the corresponding matched sub-pattern is not copied)
	</pre>
	The function returns true iff all of the following conditions are satisfied:
	<pre>
	a. "text" matches "pattern" exactly;

	b. The number of matched sub-patterns is >= number of supplied
	pointers;

	c. The "i"th argument has a suitable type for holding the
	string captured as the "i"th sub-pattern. If you pass in
	void * NULL for the "i"th argument, or a non-void * NULL
	of the correct type, or pass fewer arguments than the
	number of sub-patterns, "i"th captured sub-pattern is
	ignored.
	</pre>
	CAVEAT: An optional sub-pattern that does not exist in the matched
	string is assigned the empty string. Therefore, the following will
	return false (because the empty string is not a valid number):
	<pre>
	int number;
	pcrecpp::RE::FullMatch("abc", "[a-z]+(\\d+)?", &number);
	</pre>
	The matching interface supports at most 16 arguments per call.
	If you need more, consider using the more general interface
	<b>pcrecpp::RE::DoMatch</b>. See <b>pcrecpp.h</b> for the signature for
	<b>DoMatch</b>.
	</P>
	<P>
	NOTE: Do not use <b>no_arg</b>, which is used internally to mark the end of a
	list of optional arguments, as a placeholder for missing arguments, as this can
	lead to segfaults.
	</P>
	<br><a name="SEC4" href="#TOC1">QUOTING METACHARACTERS</a><br>
	<P>
	You can use the "QuoteMeta" operation to insert backslashes before all
	potentially meaningful characters in a string. The returned string, used as a
	regular expression, will exactly match the original string.
	<pre>
	Example:
	string quoted = RE::QuoteMeta(unquoted);
	</pre>
	Note that it's legal to escape a character even if it has no special meaning in
	a regular expression -- so this function does that. (This also makes it
	identical to the perl function of the same name; see "perldoc -f quotemeta".)
	For example, "1.5-2.0?" becomes "1\.5\-2\.0\?".
	</P>
	<br><a name="SEC5" href="#TOC1">PARTIAL MATCHES</a><br>
	<P>
	You can use the "PartialMatch" operation when you want the pattern
	to match any substring of the text.
	<pre>
	Example: simple search for a string:
	pcrecpp::RE("ell").PartialMatch("hello");

	Example: find first number in a string:
	int number;
	pcrecpp::RE re("(\\d+)");
	re.PartialMatch("x*100 + 20", &number);
	assert(number == 100);
	</PRE>
	</P>
	<br><a name="SEC6" href="#TOC1">UTF-8 AND THE MATCHING INTERFACE</a><br>
	<P>
	By default, pattern and text are plain text, one byte per character. The UTF8
	flag, passed to the constructor, causes both pattern and string to be treated
	as UTF-8 text, still a byte stream but potentially multiple bytes per
	character. In practice, the text is likelier to be UTF-8 than the pattern, but
	the match returned may depend on the UTF8 flag, so always use it when matching
	UTF8 text. For example, "." will match one byte normally but with UTF8 set may
	match up to three bytes of a multi-byte character.
	<pre>
	Example:
	pcrecpp::RE_Options options;
	options.set_utf8();
	pcrecpp::RE re(utf8_pattern, options);
	re.FullMatch(utf8_string);

	Example: using the convenience function UTF8():
	pcrecpp::RE re(utf8_pattern, pcrecpp::UTF8());
	re.FullMatch(utf8_string);
	</pre>
	NOTE: The UTF8 flag is ignored if pcre was not configured with the
	<pre>
	--enable-utf8 flag.
	</PRE>
	</P>
	<br><a name="SEC7" href="#TOC1">PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE</a><br>
	<P>
	PCRE defines some modifiers to change the behavior of the regular expression
	engine. The C++ wrapper defines an auxiliary class, RE_Options, as a vehicle to
	pass such modifiers to a RE class. Currently, the following modifiers are
	supported:
	<pre>
	modifier description Perl corresponding

	PCRE_CASELESS case insensitive match /i
	PCRE_MULTILINE multiple lines match /m
	PCRE_DOTALL dot matches newlines /s
	PCRE_DOLLAR_ENDONLY $ matches only at end N/A
	PCRE_EXTRA strict escape parsing N/A
	PCRE_EXTENDED ignore white spaces /x
	PCRE_UTF8 handles UTF8 chars built-in
	PCRE_UNGREEDY reverses * and *? N/A
	PCRE_NO_AUTO_CAPTURE disables capturing parens N/A (*)
	</pre>
	(*) Both Perl and PCRE allow non capturing parentheses by means of the
	"?:" modifier within the pattern itself. e.g. (?:ab\|cd) does not
	capture, while (ab\|cd) does.
	</P>
	<P>
	For a full account on how each modifier works, please check the
	PCRE API reference page.
	</P>
	<P>
	For each modifier, there are two member functions whose name is made
	out of the modifier in lowercase, without the "PCRE_" prefix. For
	instance, PCRE_CASELESS is handled by
	<pre>
	bool caseless()
	</pre>
	which returns true if the modifier is set, and
	<pre>
	RE_Options & set_caseless(bool)
	</pre>
	which sets or unsets the modifier. Moreover, PCRE_EXTRA_MATCH_LIMIT can be
	accessed through the <b>set_match_limit()</b> and <b>match_limit()</b> member
	functions. Setting <i>match_limit</i> to a non-zero value will limit the
	execution of pcre to keep it from doing bad things like blowing the stack or
	taking an eternity to return a result. A value of 5000 is good enough to stop
	stack blowup in a 2MB thread stack. Setting <i>match_limit</i> to zero disables
	match limiting. Alternatively, you can call <b>match_limit_recursion()</b>
	which uses PCRE_EXTRA_MATCH_LIMIT_RECURSION to limit how much PCRE
	recurses. <b>match_limit()</b> limits the number of matches PCRE does;
	<b>match_limit_recursion()</b> limits the depth of internal recursion, and
	therefore the amount of stack that is used.
	</P>
	<P>
	Normally, to pass one or more modifiers to a RE class, you declare
	a <i>RE_Options</i> object, set the appropriate options, and pass this
	object to a RE constructor. Example:
	<pre>
	RE_Options opt;
	opt.set_caseless(true);
	if (RE("HELLO", opt).PartialMatch("hello world")) ...
	</pre>
	RE_options has two constructors. The default constructor takes no arguments and
	creates a set of flags that are off by default. The optional parameter
	<i>option_flags</i> is to facilitate transfer of legacy code from C programs.
	This lets you do
	<pre>
	RE(pattern,
	RE_Options(PCRE_CASELESS\|PCRE_MULTILINE)).PartialMatch(str);
	</pre>
	However, new code is better off doing
	<pre>
	RE(pattern,
	RE_Options().set_caseless(true).set_multiline(true))
	.PartialMatch(str);
	</pre>
	If you are going to pass one of the most used modifiers, there are some
	convenience functions that return a RE_Options class with the
	appropriate modifier already set: <b>CASELESS()</b>, <b>UTF8()</b>,
	<b>MULTILINE()</b>, <b>DOTALL</b>(), and <b>EXTENDED()</b>.
	</P>
	<P>
	If you need to set several options at once, and you don't want to go through
	the pains of declaring a RE_Options object and setting several options, there
	is a parallel method that give you such ability on the fly. You can concatenate
	several <b>set_xxxxx()</b> member functions, since each of them returns a
	reference to its class object. For example, to pass PCRE_CASELESS,
	PCRE_EXTENDED, and PCRE_MULTILINE to a RE with one statement, you may write:
	<pre>
	RE(" ^ xyz \\s+ .* blah$",
	RE_Options()
	.set_caseless(true)
	.set_extended(true)
	.set_multiline(true)).PartialMatch(sometext);

	</PRE>
	</P>
	<br><a name="SEC8" href="#TOC1">SCANNING TEXT INCREMENTALLY</a><br>
	<P>
	The "Consume" operation may be useful if you want to repeatedly
	match regular expressions at the front of a string and skip over
	them as they match. This requires use of the "StringPiece" type,
	which represents a sub-range of a real string. Like RE, StringPiece
	is defined in the pcrecpp namespace.
	<pre>
	Example: read lines of the form "var = value" from a string.
	string contents = ...; // Fill string somehow
	pcrecpp::StringPiece input(contents); // Wrap in a StringPiece

	string var;
	int value;
	pcrecpp::RE re("(\\w+) = (\\d+)\n");
	while (re.Consume(&input, &var, &value)) {
	...;
	}
	</pre>
	Each successful call to "Consume" will set "var/value", and also
	advance "input" so it points past the matched text.
	</P>
	<P>
	The "FindAndConsume" operation is similar to "Consume" but does not
	anchor your match at the beginning of the string. For example, you
	could extract all words from a string by repeatedly calling
	<pre>
	pcrecpp::RE("(\\w+)").FindAndConsume(&input, &word)
	</PRE>
	</P>
	<br><a name="SEC9" href="#TOC1">PARSING HEX/OCTAL/C-RADIX NUMBERS</a><br>
	<P>
	By default, if you pass a pointer to a numeric value, the
	corresponding text is interpreted as a base-10 number. You can
	instead wrap the pointer with a call to one of the operators Hex(),
	Octal(), or CRadix() to interpret the text in another base. The
	CRadix operator interprets C-style "0" (base-8) and "0x" (base-16)
	prefixes, but defaults to base-10.
	<pre>
	Example:
	int a, b, c, d;
	pcrecpp::RE re("(.) (.) (.) (.)");
	re.FullMatch("100 40 0100 0x40",
	pcrecpp::Octal(&a), pcrecpp::Hex(&b),
	pcrecpp::CRadix(&c), pcrecpp::CRadix(&d));
	</pre>
	will leave 64 in a, b, c, and d.
	</P>
	<br><a name="SEC10" href="#TOC1">REPLACING PARTS OF STRINGS</a><br>
	<P>
	You can replace the first match of "pattern" in "str" with "rewrite".
	Within "rewrite", backslash-escaped digits (\1 to \9) can be
	used to insert text matching corresponding parenthesized group
	from the pattern. \0 in "rewrite" refers to the entire matching
	text. For example:
	<pre>
	string s = "yabba dabba doo";
	pcrecpp::RE("b+").Replace("d", &s);
	</pre>
	will leave "s" containing "yada dabba doo". The result is true if the pattern
	matches and a replacement occurs, false otherwise.
	</P>
	<P>
	<b>GlobalReplace</b> is like <b>Replace</b> except that it replaces all
	occurrences of the pattern in the string with the rewrite. Replacements are
	not subject to re-matching. For example:
	<pre>
	string s = "yabba dabba doo";
	pcrecpp::RE("b+").GlobalReplace("d", &s);
	</pre>
	will leave "s" containing "yada dada doo". It returns the number of
	replacements made.
	</P>
	<P>
	<b>Extract</b> is like <b>Replace</b>, except that if the pattern matches,
	"rewrite" is copied into "out" (an additional argument) with substitutions.
	The non-matching portions of "text" are ignored. Returns true iff a match
	occurred and the extraction happened successfully; if no match occurs, the
	string is left unaffected.
	</P>
	<br><a name="SEC11" href="#TOC1">AUTHOR</a><br>
	<P>
	The C++ wrapper was contributed by Google Inc.
	<br>
	Copyright © 2007 Google Inc.
	<br>
	</P>
	<br><a name="SEC12" href="#TOC1">REVISION</a><br>
	<P>
	Last updated: 08 January 2012
	<br>
	<p>
	Return to the <a href="index.html">PCRE index page</a>.
	</p>