// class template regex -*- C++ -*-
	
	// Copyright (C) 2010-2019 Free Software Foundation, Inc.
	//
	// This file is part of the GNU ISO C++ Library.  This library is free
	// software; you can redistribute it and/or modify it under the
	// terms of the GNU General Public License as published by the
	// Free Software Foundation; either version 3, or (at your option)
	// any later version.
	
	// This library is distributed in the hope that it will be useful,
	// but WITHOUT ANY WARRANTY; without even the implied warranty of
	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	// GNU General Public License for more details.
	
	// Under Section 7 of GPL version 3, you are granted additional
	// permissions described in the GCC Runtime Library Exception, version
	// 3.1, as published by the Free Software Foundation.
	
	// You should have received a copy of the GNU General Public License and
	// a copy of the GCC Runtime Library Exception along with this program;
	// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
	// <http://www.gnu.org/licenses/>.
	
	/**
	 *  @file bits/regex.h
	 *  This is an internal header file, included by other library headers.
	 *  Do not attempt to use it directly. @headername{regex}
	 */
	
	namespace std _GLIBCXX_VISIBILITY(default)
	{
	_GLIBCXX_BEGIN_NAMESPACE_VERSION
	_GLIBCXX_BEGIN_NAMESPACE_CXX11
	  template<typename, typename>
	    class basic_regex;
	
	  template<typename, typename>
	    class match_results;
	
	_GLIBCXX_END_NAMESPACE_CXX11
	
	namespace __detail
	{
	  enum class _RegexExecutorPolicy : int { _S_auto, _S_alternate };
	
	  template<typename _BiIter, typename _Alloc,
		   typename _CharT, typename _TraitsT,
		   _RegexExecutorPolicy __policy,
		   bool __match_mode>
	    bool
	    __regex_algo_impl(_BiIter			      __s,
			      _BiIter			      __e,
			      match_results<_BiIter, _Alloc>&      __m,
			      const basic_regex<_CharT, _TraitsT>& __re,
			      regex_constants::match_flag_type     __flags);
	
	  template<typename, typename, typename, bool>
	    class _Executor;
	}
	
	_GLIBCXX_BEGIN_NAMESPACE_CXX11
	
	  /**
	   * @addtogroup regex
	   * @{
	   */
	
	  /**
	   * @brief Describes aspects of a regular expression.
	   *
	   * A regular expression traits class that satisfies the requirements of
	   * section [28.7].
	   *
	   * The class %regex is parameterized around a set of related types and
	   * functions used to complete the definition of its semantics.  This class
	   * satisfies the requirements of such a traits class.
	   */
	  template<typename _Ch_type>
	    struct regex_traits
	    {
	    public:
	      typedef _Ch_type				char_type;
	      typedef std::basic_string<char_type>	string_type;
	      typedef std::locale			locale_type;
	    private:
	      struct _RegexMask
		{
		  typedef std::ctype_base::mask _BaseType;
		  _BaseType _M_base;
		  unsigned char _M_extended;
		  static constexpr unsigned char _S_under = 1 << 0;
		  static constexpr unsigned char _S_valid_mask = 0x1;
	
		  constexpr _RegexMask(_BaseType __base = 0,
				       unsigned char __extended = 0)
		  : _M_base(__base), _M_extended(__extended)
		  { }
	
		  constexpr _RegexMask
		  operator&(_RegexMask __other) const
		  {
		    return _RegexMask(_M_base & __other._M_base,
				      _M_extended & __other._M_extended);
		  }
	
		  constexpr _RegexMask
		  operator|(_RegexMask __other) const
		  {
		    return _RegexMask(_M_base | __other._M_base,
				      _M_extended | __other._M_extended);
		  }
	
		  constexpr _RegexMask
		  operator^(_RegexMask __other) const
		  {
		    return _RegexMask(_M_base ^ __other._M_base,
				      _M_extended ^ __other._M_extended);
		  }
	
		  constexpr _RegexMask
		  operator~() const
		  { return _RegexMask(~_M_base, ~_M_extended); }
	
		  _RegexMask&
		  operator&=(_RegexMask __other)
		  { return *this = (*this) & __other; }
	
		  _RegexMask&
		  operator|=(_RegexMask __other)
		  { return *this = (*this) | __other; }
	
		  _RegexMask&
		  operator^=(_RegexMask __other)
		  { return *this = (*this) ^ __other; }
	
		  constexpr bool
		  operator==(_RegexMask __other) const
		  {
		    return (_M_extended & _S_valid_mask)
			   == (__other._M_extended & _S_valid_mask)
			     && _M_base == __other._M_base;
		  }
	
		  constexpr bool
		  operator!=(_RegexMask __other) const
		  { return !((*this) == __other); }
	
		};
	    public:
	      typedef _RegexMask char_class_type;
	
	    public:
	      /**
	       * @brief Constructs a default traits object.
	       */
	      regex_traits() { }
	
	      /**
	       * @brief Gives the length of a C-style string starting at @p __p.
	       *
	       * @param __p a pointer to the start of a character sequence.
	       *
	       * @returns the number of characters between @p *__p and the first
	       * default-initialized value of type @p char_type.  In other words, uses
	       * the C-string algorithm for determining the length of a sequence of
	       * characters.
	       */
	      static std::size_t
	      length(const char_type* __p)
	      { return string_type::traits_type::length(__p); }
	
	      /**
	       * @brief Performs the identity translation.
	       *
	       * @param __c A character to the locale-specific character set.
	       *
	       * @returns __c.
	       */
	      char_type
	      translate(char_type __c) const
	      { return __c; }
	
	      /**
	       * @brief Translates a character into a case-insensitive equivalent.
	       *
	       * @param __c A character to the locale-specific character set.
	       *
	       * @returns the locale-specific lower-case equivalent of __c.
	       * @throws std::bad_cast if the imbued locale does not support the ctype
	       *         facet.
	       */
	      char_type
	      translate_nocase(char_type __c) const
	      {
		typedef std::ctype<char_type> __ctype_type;
		const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));
		return __fctyp.tolower(__c);
	      }
	
	      /**
	       * @brief Gets a sort key for a character sequence.
	       *
	       * @param __first beginning of the character sequence.
	       * @param __last  one-past-the-end of the character sequence.
	       *
	       * Returns a sort key for the character sequence designated by the
	       * iterator range [F1, F2) such that if the character sequence [G1, G2)
	       * sorts before the character sequence [H1, H2) then
	       * v.transform(G1, G2) < v.transform(H1, H2).
	       *
	       * What this really does is provide a more efficient way to compare a
	       * string to multiple other strings in locales with fancy collation
	       * rules and equivalence classes.
	       *
	       * @returns a locale-specific sort key equivalent to the input range.
	       *
	       * @throws std::bad_cast if the current locale does not have a collate
	       *         facet.
	       */
	      template<typename _Fwd_iter>
		string_type
		transform(_Fwd_iter __first, _Fwd_iter __last) const
		{
		  typedef std::collate<char_type> __collate_type;
		  const __collate_type& __fclt(use_facet<__collate_type>(_M_locale));
		  string_type __s(__first, __last);
		  return __fclt.transform(__s.data(), __s.data() + __s.size());
		}
	
	      /**
	       * @brief Gets a sort key for a character sequence, independent of case.
	       *
	       * @param __first beginning of the character sequence.
	       * @param __last  one-past-the-end of the character sequence.
	       *
	       * Effects: if typeid(use_facet<collate<_Ch_type> >) ==
	       * typeid(collate_byname<_Ch_type>) and the form of the sort key
	       * returned by collate_byname<_Ch_type>::transform(__first, __last)
	       * is known and can be converted into a primary sort key
	       * then returns that key, otherwise returns an empty string.
	       *
	       * @todo Implement this function correctly.
	       */
	      template<typename _Fwd_iter>
		string_type
		transform_primary(_Fwd_iter __first, _Fwd_iter __last) const
		{
		  // TODO : this is not entirely correct.
		  // This function requires extra support from the platform.
		  //
		  // Read http://gcc.gnu.org/ml/libstdc++/2013-09/msg00117.html and
		  // http://www.open-std.org/Jtc1/sc22/wg21/docs/papers/2003/n1429.htm
		  // for details.
		  typedef std::ctype<char_type> __ctype_type;
		  const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));
		  std::vector<char_type> __s(__first, __last);
		  __fctyp.tolower(__s.data(), __s.data() + __s.size());
		  return this->transform(__s.data(), __s.data() + __s.size());
		}
	
	      /**
	       * @brief Gets a collation element by name.
	       *
	       * @param __first beginning of the collation element name.
	       * @param __last  one-past-the-end of the collation element name.
	       *
	       * @returns a sequence of one or more characters that represents the
	       * collating element consisting of the character sequence designated by
	       * the iterator range [__first, __last). Returns an empty string if the
	       * character sequence is not a valid collating element.
	       */
	      template<typename _Fwd_iter>
		string_type
		lookup_collatename(_Fwd_iter __first, _Fwd_iter __last) const;
	
	      /**
	       * @brief Maps one or more characters to a named character
	       *        classification.
	       *
	       * @param __first beginning of the character sequence.
	       * @param __last  one-past-the-end of the character sequence.
	       * @param __icase ignores the case of the classification name.
	       *
	       * @returns an unspecified value that represents the character
	       * classification named by the character sequence designated by
	       * the iterator range [__first, __last). If @p icase is true,
	       * the returned mask identifies the classification regardless of
	       * the case of the characters to be matched (for example,
	       * [[:lower:]] is the same as [[:alpha:]]), otherwise a
	       * case-dependent classification is returned.  The value
	       * returned shall be independent of the case of the characters
	       * in the character sequence. If the name is not recognized then
	       * returns a value that compares equal to 0.
	       *
	       * At least the following names (or their wide-character equivalent) are
	       * supported.
	       * - d
	       * - w
	       * - s
	       * - alnum
	       * - alpha
	       * - blank
	       * - cntrl
	       * - digit
	       * - graph
	       * - lower
	       * - print
	       * - punct
	       * - space
	       * - upper
	       * - xdigit
	       */
	      template<typename _Fwd_iter>
		char_class_type
		lookup_classname(_Fwd_iter __first, _Fwd_iter __last,
				 bool __icase = false) const;
	
	      /**
	       * @brief Determines if @p c is a member of an identified class.
	       *
	       * @param __c a character.
	       * @param __f a class type (as returned from lookup_classname).
	       *
	       * @returns true if the character @p __c is a member of the classification
	       * represented by @p __f, false otherwise.
	       *
	       * @throws std::bad_cast if the current locale does not have a ctype
	       *         facet.
	       */
	      bool
	      isctype(_Ch_type __c, char_class_type __f) const;
	
	      /**
	       * @brief Converts a digit to an int.
	       *
	       * @param __ch    a character representing a digit.
	       * @param __radix the radix if the numeric conversion (limited to 8, 10,
	       *              or 16).
	       *
	       * @returns the value represented by the digit __ch in base radix if the
	       * character __ch is a valid digit in base radix; otherwise returns -1.
	       */
	      int
	      value(_Ch_type __ch, int __radix) const;
	
	      /**
	       * @brief Imbues the regex_traits object with a copy of a new locale.
	       *
	       * @param __loc A locale.
	       *
	       * @returns a copy of the previous locale in use by the regex_traits
	       *          object.
	       *
	       * @note Calling imbue with a different locale than the one currently in
	       *       use invalidates all cached data held by *this.
	       */
	      locale_type
	      imbue(locale_type __loc)
	      {
		std::swap(_M_locale, __loc);
		return __loc;
	      }
	
	      /**
	       * @brief Gets a copy of the current locale in use by the regex_traits
	       * object.
	       */
	      locale_type
	      getloc() const
	      { return _M_locale; }
	
	    protected:
	      locale_type _M_locale;
	    };
	
	  // [7.8] Class basic_regex
	  /**
	   * Objects of specializations of this class represent regular expressions
	   * constructed from sequences of character type @p _Ch_type.
	   *
	   * Storage for the regular expression is allocated and deallocated as
	   * necessary by the member functions of this class.
	   */
	  template<typename _Ch_type, typename _Rx_traits = regex_traits<_Ch_type>>
	    class basic_regex
	    {
	    public:
	      static_assert(is_same<_Ch_type, typename _Rx_traits::char_type>::value,
			    "regex traits class must have the same char_type");
	
	      // types:
	      typedef _Ch_type				  value_type;
	      typedef _Rx_traits			  traits_type;
	      typedef typename traits_type::string_type   string_type;
	      typedef regex_constants::syntax_option_type flag_type;
	      typedef typename traits_type::locale_type   locale_type;
	
	      /**
	       * @name Constants
	       * std [28.8.1](1)
	       */
	      //@{
	      static constexpr flag_type icase = regex_constants::icase;
	      static constexpr flag_type nosubs = regex_constants::nosubs;
	      static constexpr flag_type optimize = regex_constants::optimize;
	      static constexpr flag_type collate = regex_constants::collate;
	      static constexpr flag_type ECMAScript = regex_constants::ECMAScript;
	      static constexpr flag_type basic = regex_constants::basic;
	      static constexpr flag_type extended = regex_constants::extended;
	      static constexpr flag_type awk = regex_constants::awk;
	      static constexpr flag_type grep = regex_constants::grep;
	      static constexpr flag_type egrep = regex_constants::egrep;
	      //@}
	
	      // [7.8.2] construct/copy/destroy
	      /**
	       * Constructs a basic regular expression that does not match any
	       * character sequence.
	       */
	      basic_regex()
	      : _M_flags(ECMAScript), _M_loc(), _M_automaton(nullptr)
	      { }
	
	      /**
	       * @brief Constructs a basic regular expression from the
	       * sequence [__p, __p + char_traits<_Ch_type>::length(__p))
	       * interpreted according to the flags in @p __f.
	       *
	       * @param __p A pointer to the start of a C-style null-terminated string
	       *          containing a regular expression.
	       * @param __f Flags indicating the syntax rules and options.
	       *
	       * @throws regex_error if @p __p is not a valid regular expression.
	       */
	      explicit
	      basic_regex(const _Ch_type* __p, flag_type __f = ECMAScript)

	      : basic_regex(__p, __p + char_traits<_Ch_type>::length(__p), __f)
	      { }
	
	      /**
	       * @brief Constructs a basic regular expression from the sequence
	       * [p, p + len) interpreted according to the flags in @p f.
	       *
	       * @param __p   A pointer to the start of a string containing a regular
	       *              expression.
	       * @param __len The length of the string containing the regular
	       *              expression.
	       * @param __f   Flags indicating the syntax rules and options.
	       *
	       * @throws regex_error if @p __p is not a valid regular expression.
	       */
	      basic_regex(const _Ch_type* __p, std::size_t __len,
			  flag_type __f = ECMAScript)
	      : basic_regex(__p, __p + __len, __f)
	      { }
	
	      /**
	       * @brief Copy-constructs a basic regular expression.
	       *
	       * @param __rhs A @p regex object.
	       */
	      basic_regex(const basic_regex& __rhs) = default;
	
	      /**
	       * @brief Move-constructs a basic regular expression.
	       *
	       * @param __rhs A @p regex object.
	       */
	      basic_regex(basic_regex&& __rhs) noexcept = default;
	
	      /**
	       * @brief Constructs a basic regular expression from the string
	       * @p s interpreted according to the flags in @p f.
	       *
	       * @param __s A string containing a regular expression.
	       * @param __f Flags indicating the syntax rules and options.
	       *
	       * @throws regex_error if @p __s is not a valid regular expression.
	       */
	      template<typename _Ch_traits, typename _Ch_alloc>
		explicit
		basic_regex(const std::basic_string<_Ch_type, _Ch_traits,
						    _Ch_alloc>& __s,
			    flag_type __f = ECMAScript)
		: basic_regex(__s.data(), __s.data() + __s.size(), __f)
		{ }
	
	      /**
	       * @brief Constructs a basic regular expression from the range
	       * [first, last) interpreted according to the flags in @p f.
	       *
	       * @param __first The start of a range containing a valid regular
	       *                expression.
	       * @param __last  The end of a range containing a valid regular
	       *                expression.
	       * @param __f     The format flags of the regular expression.
	       *
	       * @throws regex_error if @p [__first, __last) is not a valid regular
	       *         expression.
	       */
	      template<typename _FwdIter>
		basic_regex(_FwdIter __first, _FwdIter __last,
			    flag_type __f = ECMAScript)

		: basic_regex(std::move(__first), std::move(__last), locale_type(), __f)
		{ }
	
	      /**
	       * @brief Constructs a basic regular expression from an initializer list.
	       *
	       * @param __l  The initializer list.
	       * @param __f  The format flags of the regular expression.
	       *
	       * @throws regex_error if @p __l is not a valid regular expression.
	       */
	      basic_regex(initializer_list<_Ch_type> __l, flag_type __f = ECMAScript)
	      : basic_regex(__l.begin(), __l.end(), __f)
	      { }
	
	      /**
	       * @brief Destroys a basic regular expression.
	       */
	      ~basic_regex()
	      { }
	
	      /**
	       * @brief Assigns one regular expression to another.
	       */
	      basic_regex&
	      operator=(const basic_regex& __rhs)
	      { return this->assign(__rhs); }
	
	      /**
	       * @brief Move-assigns one regular expression to another.
	       */
	      basic_regex&
	      operator=(basic_regex&& __rhs) noexcept
	      { return this->assign(std::move(__rhs)); }
	
	      /**
	       * @brief Replaces a regular expression with a new one constructed from
	       * a C-style null-terminated string.
	       *
	       * @param __p A pointer to the start of a null-terminated C-style string
	       *        containing a regular expression.
	       */
	      basic_regex&
	      operator=(const _Ch_type* __p)
	      { return this->assign(__p); }
	
	      /**
	       * @brief Replaces a regular expression with a new one constructed from
	       * an initializer list.
	       *
	       * @param __l  The initializer list.
	       *
	       * @throws regex_error if @p __l is not a valid regular expression.
	       */
	      basic_regex&
	      operator=(initializer_list<_Ch_type> __l)
	      { return this->assign(__l.begin(), __l.end()); }
	
	      /**
	       * @brief Replaces a regular expression with a new one constructed from
	       * a string.
	       *
	       * @param __s A pointer to a string containing a regular expression.
	       */
	      template<typename _Ch_traits, typename _Alloc>
		basic_regex&
		operator=(const basic_string<_Ch_type, _Ch_traits, _Alloc>& __s)
		{ return this->assign(__s); }
	
	      // [7.8.3] assign
	      /**
	       * @brief the real assignment operator.
	       *
	       * @param __rhs Another regular expression object.
	       */
	      basic_regex&
	      assign(const basic_regex& __rhs)
	      {
		basic_regex __tmp(__rhs);
		this->swap(__tmp);
		return *this;
	      }
	
	      /**
	       * @brief The move-assignment operator.
	       *
	       * @param __rhs Another regular expression object.
	       */
	      basic_regex&
	      assign(basic_regex&& __rhs) noexcept
	      {
		basic_regex __tmp(std::move(__rhs));
		this->swap(__tmp);
		return *this;
	      }
	
	      /**
	       * @brief Assigns a new regular expression to a regex object from a
	       * C-style null-terminated string containing a regular expression
	       * pattern.
	       *
	       * @param __p     A pointer to a C-style null-terminated string containing
	       *              a regular expression pattern.
	       * @param __flags Syntax option flags.
	       *
	       * @throws regex_error if __p does not contain a valid regular
	       * expression pattern interpreted according to @p __flags.  If
	       * regex_error is thrown, *this remains unchanged.
	       */
	      basic_regex&
	      assign(const _Ch_type* __p, flag_type __flags = ECMAScript)
	      { return this->assign(string_type(__p), __flags); }
	
	      /**
	       * @brief Assigns a new regular expression to a regex object from a
	       * C-style string containing a regular expression pattern.
	       *
	       * @param __p     A pointer to a C-style string containing a
	       *                regular expression pattern.
	       * @param __len   The length of the regular expression pattern string.
	       * @param __flags Syntax option flags.
	       *
	       * @throws regex_error if p does not contain a valid regular
	       * expression pattern interpreted according to @p __flags.  If
	       * regex_error is thrown, *this remains unchanged.
	       */
	      basic_regex&
	      assign(const _Ch_type* __p, std::size_t __len, flag_type __flags)
	      { return this->assign(string_type(__p, __len), __flags); }
	
	      /**
	       * @brief Assigns a new regular expression to a regex object from a
	       * string containing a regular expression pattern.
	       *
	       * @param __s     A string containing a regular expression pattern.
	       * @param __flags Syntax option flags.
	       *
	       * @throws regex_error if __s does not contain a valid regular
	       * expression pattern interpreted according to @p __flags.  If
	       * regex_error is thrown, *this remains unchanged.
	       */
	      template<typename _Ch_traits, typename _Alloc>
		basic_regex&
		assign(const basic_string<_Ch_type, _Ch_traits, _Alloc>& __s,
		       flag_type __flags = ECMAScript)
		{
		  return this->assign(basic_regex(__s.data(), __s.data() + __s.size(),
						  _M_loc, __flags));
		}
	
	      /**
	       * @brief Assigns a new regular expression to a regex object.
	       *
	       * @param __first The start of a range containing a valid regular
	       *                expression.
	       * @param __last  The end of a range containing a valid regular
	       *                expression.
	       * @param __flags Syntax option flags.
	       *
	       * @throws regex_error if p does not contain a valid regular
	       * expression pattern interpreted according to @p __flags.  If
	       * regex_error is thrown, the object remains unchanged.
	       */
	      template<typename _InputIterator>
		basic_regex&
		assign(_InputIterator __first, _InputIterator __last,
		       flag_type __flags = ECMAScript)
		{ return this->assign(string_type(__first, __last), __flags); }
	
	      /**
	       * @brief Assigns a new regular expression to a regex object.
	       *
	       * @param __l     An initializer list representing a regular expression.
	       * @param __flags Syntax option flags.
	       *
	       * @throws regex_error if @p __l does not contain a valid
	       * regular expression pattern interpreted according to @p
	       * __flags.  If regex_error is thrown, the object remains
	       * unchanged.
	       */
	      basic_regex&
	      assign(initializer_list<_Ch_type> __l, flag_type __flags = ECMAScript)
	      { return this->assign(__l.begin(), __l.end(), __flags); }
	
	      // [7.8.4] const operations
	      /**
	       * @brief Gets the number of marked subexpressions within the regular
	       * expression.
	       */
	      unsigned int
	      mark_count() const
	      {
		if (_M_automaton)
		  return _M_automaton->_M_sub_count() - 1;
		return 0;
	      }
	
	      /**
	       * @brief Gets the flags used to construct the regular expression
	       * or in the last call to assign().
	       */
	      flag_type
	      flags() const
	      { return _M_flags; }
	
	      // [7.8.5] locale
	      /**
	       * @brief Imbues the regular expression object with the given locale.
	       *
	       * @param __loc A locale.
	       */
	      locale_type
	      imbue(locale_type __loc)
	      {
		std::swap(__loc, _M_loc);
		_M_automaton.reset();
		return __loc;
	      }
	
	      /**
	       * @brief Gets the locale currently imbued in the regular expression
	       *        object.
	       */
	      locale_type
	      getloc() const
	      { return _M_loc; }
	
	      // [7.8.6] swap
	      /**
	       * @brief Swaps the contents of two regular expression objects.
	       *
	       * @param __rhs Another regular expression object.
	       */
	      void
	      swap(basic_regex& __rhs)
	      {
		std::swap(_M_flags, __rhs._M_flags);
		std::swap(_M_loc, __rhs._M_loc);
		std::swap(_M_automaton, __rhs._M_automaton);
	      }
	
	#ifdef _GLIBCXX_DEBUG
	      void
	      _M_dot(std::ostream& __ostr)
	      { _M_automaton->_M_dot(__ostr); }
	#endif
	
	    private:
	      typedef std::shared_ptr<const __detail::_NFA<_Rx_traits>> _AutomatonPtr;
	
	      template<typename _FwdIter>
		basic_regex(_FwdIter __first, _FwdIter __last, locale_type __loc,
			    flag_type __f)
		: _M_flags(__f), _M_loc(std::move(__loc)),

		_M_automaton(__detail::__compile_nfa<_Rx_traits>(
		  std::move(__first), std::move(__last), _M_loc, _M_flags))
		{ }
	
	      template<typename _Bp, typename _Ap, typename _Cp, typename _Rp,
		__detail::_RegexExecutorPolicy, bool>
		friend bool
		__detail::__regex_algo_impl(_Bp, _Bp, match_results<_Bp, _Ap>&,
					    const basic_regex<_Cp, _Rp>&,
					    regex_constants::match_flag_type);
	
	      template<typename, typename, typename, bool>
		friend class __detail::_Executor;
	
	      flag_type		_M_flags;
	      locale_type	_M_loc;
	      _AutomatonPtr	_M_automaton;
	    };
	
	#if __cplusplus < 201703L
	  template<typename _Ch, typename _Tr>
	    constexpr regex_constants::syntax_option_type
	    basic_regex<_Ch, _Tr>::icase;
	
	  template<typename _Ch, typename _Tr>
	    constexpr regex_constants::syntax_option_type
	    basic_regex<_Ch, _Tr>::nosubs;
	
	  template<typename _Ch, typename _Tr>
	    constexpr regex_constants::syntax_option_type
	    basic_regex<_Ch, _Tr>::optimize;
	
	  template<typename _Ch, typename _Tr>
	    constexpr regex_constants::syntax_option_type
	    basic_regex<_Ch, _Tr>::collate;
	
	  template<typename _Ch, typename _Tr>
	    constexpr regex_constants::syntax_option_type
	    basic_regex<_Ch, _Tr>::ECMAScript;
	
	  template<typename _Ch, typename _Tr>
	    constexpr regex_constants::syntax_option_type
	    basic_regex<_Ch, _Tr>::basic;
	
	  template<typename _Ch, typename _Tr>
	    constexpr regex_constants::syntax_option_type
	    basic_regex<_Ch, _Tr>::extended;
	
	  template<typename _Ch, typename _Tr>
	    constexpr regex_constants::syntax_option_type
	    basic_regex<_Ch, _Tr>::awk;
	
	  template<typename _Ch, typename _Tr>
	    constexpr regex_constants::syntax_option_type
	    basic_regex<_Ch, _Tr>::grep;
	
	  template<typename _Ch, typename _Tr>
	    constexpr regex_constants::syntax_option_type
	    basic_regex<_Ch, _Tr>::egrep;
	#endif // ! C++17
	
	#if __cpp_deduction_guides >= 201606
	  template<typename _ForwardIterator>
	    basic_regex(_ForwardIterator, _ForwardIterator,
			regex_constants::syntax_option_type = {})
	      -> basic_regex<typename iterator_traits<_ForwardIterator>::value_type>;
	#endif
	
	  /** @brief Standard regular expressions. */
	  typedef basic_regex<char>    regex;
	
	#ifdef _GLIBCXX_USE_WCHAR_T
	  /** @brief Standard wide-character regular expressions. */
	  typedef basic_regex<wchar_t> wregex;
	#endif
	
	
	  // [7.8.6] basic_regex swap
	  /**
	   * @brief Swaps the contents of two regular expression objects.
	   * @param __lhs First regular expression.
	   * @param __rhs Second regular expression.
	   */
	  template<typename _Ch_type, typename _Rx_traits>
	    inline void
	    swap(basic_regex<_Ch_type, _Rx_traits>& __lhs,
		 basic_regex<_Ch_type, _Rx_traits>& __rhs)
	    { __lhs.swap(__rhs); }
	
	
	  // C++11 28.9 [re.submatch] Class template sub_match
	  /**
	   * A sequence of characters matched by a particular marked sub-expression.
	   *
	   * An object of this class is essentially a pair of iterators marking a
	   * matched subexpression within a regular expression pattern match. Such
	   * objects can be converted to and compared with std::basic_string objects
	   * of a similar base character type as the pattern matched by the regular
	   * expression.
	   *
	   * The iterators that make up the pair are the usual half-open interval
	   * referencing the actual original pattern matched.
	   */
	  template<typename _BiIter>
	    class sub_match : public std::pair<_BiIter, _BiIter>
	    {
	      typedef iterator_traits<_BiIter>			__iter_traits;
		
	    public:
	      typedef typename __iter_traits::value_type      	value_type;
	      typedef typename __iter_traits::difference_type 	difference_type;
	      typedef _BiIter					iterator;
	      typedef basic_string<value_type>			string_type;
	
	      bool matched;
	
	      constexpr sub_match() noexcept : matched() { }
	
	      /// Gets the length of the matching sequence.
	      difference_type
	      length() const noexcept
	      { return this->matched ? std::distance(this->first, this->second) : 0; }
	
	      /**
	       * @brief Gets the matching sequence as a string.
	       *
	       * @returns the matching sequence as a string.
	       *
	       * This is the implicit conversion operator.  It is identical to the
	       * str() member function except that it will want to pop up in
	       * unexpected places and cause a great deal of confusion and cursing
	       * from the unwary.
	       */
	      operator string_type() const
	      { return str(); }
	
	      /**
	       * @brief Gets the matching sequence as a string.
	       *
	       * @returns the matching sequence as a string.
	       */
	      string_type
	      str() const
	      {
		return this->matched
		  ? string_type(this->first, this->second)
		  : string_type();
	      }
	
	      /**
	       * @brief Compares this and another matched sequence.
	       *
	       * @param __s Another matched sequence to compare to this one.
	       *
	       * @retval <0 this matched sequence will collate before @p __s.
	       * @retval =0 this matched sequence is equivalent to @p __s.
	       * @retval <0 this matched sequence will collate after @p __s.
	       */
	      int
	      compare(const sub_match& __s) const
	      { return this->_M_str().compare(__s._M_str()); }
	
	      /**
	       * @{
	       * @brief Compares this sub_match to a string.
	       *
	       * @param __s A string to compare to this sub_match.
	       *
	       * @retval <0 this matched sequence will collate before @p __s.
	       * @retval =0 this matched sequence is equivalent to @p __s.
	       * @retval <0 this matched sequence will collate after @p __s.
	       */
	      int
	      compare(const string_type& __s) const
	      { return this->_M_str().compare(__s); }
	
	      int
	      compare(const value_type* __s) const
	      { return this->_M_str().compare(__s); }
	      // @}
	
	      // Non-standard, used by comparison operators
	      int
	      _M_compare(const value_type* __s, size_t __n) const
	      { return this->_M_str().compare({__s, __n}); }
	
	    private:
	      // Simplified basic_string_view for C++11
	      struct __string_view
	      {
		using traits_type = typename string_type::traits_type;
	
		__string_view() = default;
	
		__string_view(const value_type* __s, size_t __n) noexcept
		: _M_data(__s), _M_len(__n) { }
	
		__string_view(const value_type* __s) noexcept
		: _M_data(__s), _M_len(traits_type::length(__s)) { }
	
		__string_view(const string_type& __s) noexcept
		: _M_data(__s.data()), _M_len(__s.length()) { }
	
		int
		compare(__string_view __s) const noexcept
		{
		  if (const size_t __n = std::min(_M_len, __s._M_len))
		    if (int __ret = traits_type::compare(_M_data, __s._M_data, __n))
		      return __ret;
		  const difference_type __diff = _M_len - __s._M_len;
		  if (__diff > std::numeric_limits<int>::max())
		    return std::numeric_limits<int>::max();
		  if (__diff < std::numeric_limits<int>::min())
		    return std::numeric_limits<int>::min();
		  return static_cast<int>(__diff);
		}
	
	      private:
		const value_type* _M_data = nullptr;
		size_t _M_len = 0;
	      };
	
	      // Create a __string_view over the iterator range.
	      template<typename _Iter = _BiIter>
		__enable_if_t<__detail::__is_contiguous_iter<_Iter>::value,
			      __string_view>
		_M_str() const noexcept
		{
		  if (this->matched)
		    if (auto __len = this->second - this->first)
		      return { std::__addressof(*this->first), __len };
		  return {};
		}
	
	      // Create a temporary string that can be converted to __string_view.
	      template<typename _Iter = _BiIter>
		__enable_if_t<!__detail::__is_contiguous_iter<_Iter>::value,
			      string_type>
		_M_str() const
		{ return str(); }
	    };
	
	
	  /** @brief Standard regex submatch over a C-style null-terminated string. */
	  typedef sub_match<const char*>	     csub_match;
	
	  /** @brief Standard regex submatch over a standard string. */
	  typedef sub_match<string::const_iterator>  ssub_match;
	
	#ifdef _GLIBCXX_USE_WCHAR_T
	  /** @brief Regex submatch over a C-style null-terminated wide string. */
	  typedef sub_match<const wchar_t*>	  wcsub_match;
	
	  /** @brief Regex submatch over a standard wide string. */
	  typedef sub_match<wstring::const_iterator> wssub_match;
	#endif
	
	  // [7.9.2] sub_match non-member operators
	
	  /**
	   * @brief Tests the equivalence of two regular expression submatches.
	   * @param __lhs First regular expression submatch.
	   * @param __rhs Second regular expression submatch.
	   * @returns true if @a __lhs  is equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _BiIter>
	    inline bool
	    operator==(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
	    { return __lhs.compare(__rhs) == 0; }
	
	  /**
	   * @brief Tests the inequivalence of two regular expression submatches.
	   * @param __lhs First regular expression submatch.
	   * @param __rhs Second regular expression submatch.
	   * @returns true if @a __lhs  is not equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _BiIter>
	    inline bool
	    operator!=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
	    { return __lhs.compare(__rhs) != 0; }
	
	  /**
	   * @brief Tests the ordering of two regular expression submatches.
	   * @param __lhs First regular expression submatch.
	   * @param __rhs Second regular expression submatch.
	   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
	   */
	  template<typename _BiIter>
	    inline bool
	    operator<(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
	    { return __lhs.compare(__rhs) < 0; }
	
	  /**
	   * @brief Tests the ordering of two regular expression submatches.
	   * @param __lhs First regular expression submatch.
	   * @param __rhs Second regular expression submatch.
	   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
	   */
	  template<typename _BiIter>
	    inline bool
	    operator<=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
	    { return __lhs.compare(__rhs) <= 0; }
	
	  /**
	   * @brief Tests the ordering of two regular expression submatches.
	   * @param __lhs First regular expression submatch.
	   * @param __rhs Second regular expression submatch.
	   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
	   */
	  template<typename _BiIter>
	    inline bool
	    operator>=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
	    { return __lhs.compare(__rhs) >= 0; }
	
	  /**
	   * @brief Tests the ordering of two regular expression submatches.
	   * @param __lhs First regular expression submatch.
	   * @param __rhs Second regular expression submatch.
	   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
	   */
	  template<typename _BiIter>
	    inline bool
	    operator>(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
	    { return __lhs.compare(__rhs) > 0; }
	
	  // Alias for a basic_string that can be compared to a sub_match.
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    using __sub_match_string = basic_string<
				      typename iterator_traits<_Bi_iter>::value_type,
				      _Ch_traits, _Ch_alloc>;
	
	  /**
	   * @brief Tests the equivalence of a string and a regular expression
	   *        submatch.
	   * @param __lhs A string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs  is equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator==(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return __rhs._M_compare(__lhs.data(), __lhs.size()) == 0; }
	
	  /**
	   * @brief Tests the inequivalence of a string and a regular expression
	   *        submatch.
	   * @param __lhs A string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs  is not equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator!=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return !(__lhs == __rhs); }
	
	  /**
	   * @brief Tests the ordering of a string and a regular expression submatch.
	   * @param __lhs A string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator<(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
		      const sub_match<_Bi_iter>& __rhs)
	    { return __rhs._M_compare(__lhs.data(), __lhs.size()) > 0; }
	
	  /**
	   * @brief Tests the ordering of a string and a regular expression submatch.
	   * @param __lhs A string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator>(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
		      const sub_match<_Bi_iter>& __rhs)
	    { return __rhs < __lhs; }
	
	  /**
	   * @brief Tests the ordering of a string and a regular expression submatch.
	   * @param __lhs A string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator>=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return !(__lhs < __rhs); }
	
	  /**
	   * @brief Tests the ordering of a string and a regular expression submatch.
	   * @param __lhs A string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator<=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return !(__rhs < __lhs); }
	
	  /**
	   * @brief Tests the equivalence of a regular expression submatch and a
	   *        string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A string.
	   * @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator==(const sub_match<_Bi_iter>& __lhs,
		       const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
	    { return __lhs._M_compare(__rhs.data(), __rhs.size()) == 0; }
	
	  /**
	   * @brief Tests the inequivalence of a regular expression submatch and a
	   *        string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A string.
	   * @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator!=(const sub_match<_Bi_iter>& __lhs,
		       const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
	    { return !(__lhs == __rhs); }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A string.
	   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator<(const sub_match<_Bi_iter>& __lhs,
		      const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
	    { return __lhs._M_compare(__rhs.data(), __rhs.size()) < 0; }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A string.
	   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator>(const sub_match<_Bi_iter>& __lhs,
		      const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
	    { return __rhs < __lhs; }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A string.
	   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator>=(const sub_match<_Bi_iter>& __lhs,
		       const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
	    { return !(__lhs < __rhs); }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A string.
	   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
	    inline bool
	    operator<=(const sub_match<_Bi_iter>& __lhs,
		       const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
	    { return !(__rhs < __lhs); }
	
	  /**
	   * @brief Tests the equivalence of a C string and a regular expression
	   *        submatch.
	   * @param __lhs A null-terminated string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs  is equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator==(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return __rhs.compare(__lhs) == 0; }
	
	  /**
	   * @brief Tests the inequivalence of a C string and a regular
	   *        expression submatch.
	   * @param __lhs A null-terminated string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator!=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return !(__lhs == __rhs); }
	
	  /**
	   * @brief Tests the ordering of a C string and a regular expression submatch.
	   * @param __lhs A null-terminated string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator<(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
		      const sub_match<_Bi_iter>& __rhs)
	    { return __rhs.compare(__lhs) > 0; }
	
	  /**
	   * @brief Tests the ordering of a C string and a regular expression submatch.
	   * @param __lhs A null-terminated string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator>(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
		      const sub_match<_Bi_iter>& __rhs)
	    { return __rhs < __lhs; }
	
	  /**
	   * @brief Tests the ordering of a C string and a regular expression submatch.
	   * @param __lhs A null-terminated string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator>=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return !(__lhs < __rhs); }
	
	  /**
	   * @brief Tests the ordering of a C string and a regular expression submatch.
	   * @param __lhs A null-terminated string.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator<=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return !(__rhs < __lhs); }
	
	  /**
	   * @brief Tests the equivalence of a regular expression submatch and a C
	   *        string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A null-terminated string.
	   * @returns true if @a __lhs  is equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator==(const sub_match<_Bi_iter>& __lhs,
		       typename iterator_traits<_Bi_iter>::value_type const* __rhs)
	    { return __lhs.compare(__rhs) == 0; }
	
	  /**
	   * @brief Tests the inequivalence of a regular expression submatch and a
	   *        string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A null-terminated string.
	   * @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator!=(const sub_match<_Bi_iter>& __lhs,
		       typename iterator_traits<_Bi_iter>::value_type const* __rhs)
	    { return !(__lhs == __rhs); }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a C string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A null-terminated string.
	   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator<(const sub_match<_Bi_iter>& __lhs,
		      typename iterator_traits<_Bi_iter>::value_type const* __rhs)
	    { return __lhs.compare(__rhs) < 0; }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a C string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A null-terminated string.
	   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator>(const sub_match<_Bi_iter>& __lhs,
		      typename iterator_traits<_Bi_iter>::value_type const* __rhs)
	    { return __rhs < __lhs; }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a C string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A null-terminated string.
	   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator>=(const sub_match<_Bi_iter>& __lhs,
		       typename iterator_traits<_Bi_iter>::value_type const* __rhs)
	    { return !(__lhs < __rhs); }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a C string.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A null-terminated string.
	   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator<=(const sub_match<_Bi_iter>& __lhs,
		       typename iterator_traits<_Bi_iter>::value_type const* __rhs)
	    { return !(__rhs < __lhs); }
	
	  /**
	   * @brief Tests the equivalence of a character and a regular expression
	   *        submatch.
	   * @param __lhs A character.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator==(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return __rhs._M_compare(std::__addressof(__lhs), 1) == 0; }
	
	  /**
	   * @brief Tests the inequivalence of a character and a regular expression
	   *        submatch.
	   * @param __lhs A character.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator!=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return !(__lhs == __rhs); }
	
	  /**
	   * @brief Tests the ordering of a character and a regular expression
	   *        submatch.
	   * @param __lhs A character.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator<(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
		      const sub_match<_Bi_iter>& __rhs)
	    { return __rhs._M_compare(std::__addressof(__lhs), 1) > 0; }
	
	  /**
	   * @brief Tests the ordering of a character and a regular expression
	   *        submatch.
	   * @param __lhs A character.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator>(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
		      const sub_match<_Bi_iter>& __rhs)
	    { return __rhs < __lhs; }
	
	  /**
	   * @brief Tests the ordering of a character and a regular expression
	   *        submatch.
	   * @param __lhs A character.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator>=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return !(__lhs < __rhs); }
	
	  /**
	   * @brief Tests the ordering of a character and a regular expression
	   *        submatch.
	   * @param __lhs A character.
	   * @param __rhs A regular expression submatch.
	   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator<=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
		       const sub_match<_Bi_iter>& __rhs)
	    { return !(__rhs < __lhs); }
	
	  /**
	   * @brief Tests the equivalence of a regular expression submatch and a
	   *        character.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A character.
	   * @returns true if @a __lhs  is equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator==(const sub_match<_Bi_iter>& __lhs,
		       typename iterator_traits<_Bi_iter>::value_type const& __rhs)
	    { return __lhs._M_compare(std::__addressof(__rhs), 1) == 0; }
	
	  /**
	   * @brief Tests the inequivalence of a regular expression submatch and a
	   *        character.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A character.
	   * @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator!=(const sub_match<_Bi_iter>& __lhs,
		       typename iterator_traits<_Bi_iter>::value_type const& __rhs)
	    { return !(__lhs == __rhs); }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a
	   *        character.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A character.
	   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator<(const sub_match<_Bi_iter>& __lhs,
		      typename iterator_traits<_Bi_iter>::value_type const& __rhs)
	    { return __lhs._M_compare(std::__addressof(__rhs), 1) < 0; }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a
	   *        character.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A character.
	   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator>(const sub_match<_Bi_iter>& __lhs,
		      typename iterator_traits<_Bi_iter>::value_type const& __rhs)
	    { return __rhs < __lhs; }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a
	   *        character.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A character.
	   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator>=(const sub_match<_Bi_iter>& __lhs,
		       typename iterator_traits<_Bi_iter>::value_type const& __rhs)
	    { return !(__lhs < __rhs); }
	
	  /**
	   * @brief Tests the ordering of a regular expression submatch and a
	   *        character.
	   * @param __lhs A regular expression submatch.
	   * @param __rhs A character.
	   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
	   */
	  template<typename _Bi_iter>
	    inline bool
	    operator<=(const sub_match<_Bi_iter>& __lhs,
		       typename iterator_traits<_Bi_iter>::value_type const& __rhs)
	    { return !(__rhs < __lhs); }
	
	  /**
	   * @brief Inserts a matched string into an output stream.
	   *
	   * @param __os The output stream.
	   * @param __m  A submatch string.
	   *
	   * @returns the output stream with the submatch string inserted.
	   */
	  template<typename _Ch_type, typename _Ch_traits, typename _Bi_iter>
	    inline
	    basic_ostream<_Ch_type, _Ch_traits>&
	    operator<<(basic_ostream<_Ch_type, _Ch_traits>& __os,
		       const sub_match<_Bi_iter>& __m)
	    { return __os << __m.str(); }
	
	  // [7.10] Class template match_results
	
	  /**
	   * @brief The results of a match or search operation.
	   *
	   * A collection of character sequences representing the result of a regular
	   * expression match.  Storage for the collection is allocated and freed as
	   * necessary by the member functions of class template match_results.
	   *
	   * This class satisfies the Sequence requirements, with the exception that
	   * only the operations defined for a const-qualified Sequence are supported.
	   *
	   * The sub_match object stored at index 0 represents sub-expression 0, i.e.
	   * the whole match. In this case the %sub_match member matched is always true.
	   * The sub_match object stored at index n denotes what matched the marked
	   * sub-expression n within the matched expression. If the sub-expression n
	   * participated in a regular expression match then the %sub_match member
	   * matched evaluates to true, and members first and second denote the range
	   * of characters [first, second) which formed that match. Otherwise matched
	   * is false, and members first and second point to the end of the sequence
	   * that was searched.
	   *
	   * @nosubgrouping
	   */
	  template<typename _Bi_iter,
		   typename _Alloc = allocator<sub_match<_Bi_iter> > >
	    class match_results
	    : private std::vector<sub_match<_Bi_iter>, _Alloc>
	    {
	    private:
	      /*
	       * The vector base is empty if this does not represent a match (!ready());
	       * Otherwise if it's a match failure, it contains 3 elements:
	       * [0] unmatched
	       * [1] prefix
	       * [2] suffix
	       * Otherwise it contains n+4 elements where n is the number of marked
	       * sub-expressions:
	       * [0] entire match
	       * [1] 1st marked subexpression
	       * ...
	       * [n] nth marked subexpression
	       * [n+1] unmatched
	       * [n+2] prefix
	       * [n+3] suffix
	       */
	      typedef std::vector<sub_match<_Bi_iter>, _Alloc>     _Base_type;
	      typedef std::iterator_traits<_Bi_iter>   	   	   __iter_traits;
	      typedef regex_constants::match_flag_type		   match_flag_type;
	
	    public:
	      /**
	       * @name 10.? Public Types
	       */
	      //@{
	      typedef sub_match<_Bi_iter>			   value_type;
	      typedef const value_type&				   const_reference;
	      typedef value_type&				   reference;
	      typedef typename _Base_type::const_iterator	   const_iterator;
	      typedef const_iterator				   iterator;
	      typedef typename __iter_traits::difference_type	   difference_type;
	      typedef typename allocator_traits<_Alloc>::size_type size_type;
	      typedef _Alloc					   allocator_type;
	      typedef typename __iter_traits::value_type 	   char_type;
	      typedef std::basic_string<char_type>		   string_type;
	      //@}
	
	    public:
	      /**
	       * @name 28.10.1 Construction, Copying, and Destruction
	       */
	      //@{
	
	      /**
	       * @brief Constructs a default %match_results container.
	       * @post size() returns 0 and str() returns an empty string.
	       * @{
	       */
	      match_results() : match_results(_Alloc()) { }
	
	      explicit
	      match_results(const _Alloc& __a) noexcept
	      : _Base_type(__a)
	      { }
	
	      // @}
	
	      /**
	       * @brief Copy constructs a %match_results.
	       */
	      match_results(const match_results&) = default;
	
	      /**
	       * @brief Move constructs a %match_results.
	       */
	      match_results(match_results&&) noexcept = default;
	
	      /**
	       * @brief Assigns rhs to *this.
	       */
	      match_results&
	      operator=(const match_results&) = default;
	
	      /**
	       * @brief Move-assigns rhs to *this.
	       */
	      match_results&
	      operator=(match_results&&) = default;
	
	      /**
	       * @brief Destroys a %match_results object.
	       */
	      ~match_results() = default;
	
	      //@}
	
	      // 28.10.2, state:
	      /**
	       * @brief Indicates if the %match_results is ready.
	       * @retval true   The object has a fully-established result state.
	       * @retval false  The object is not ready.
	       */
	      bool ready() const noexcept { return !_Base_type::empty(); }
	
	      /**
	       * @name 28.10.2 Size
	       */
	      //@{
	
	      /**
	       * @brief Gets the number of matches and submatches.
	       *
	       * The number of matches for a given regular expression will be either 0
	       * if there was no match or mark_count() + 1 if a match was successful.
	       * Some matches may be empty.
	       *
	       * @returns the number of matches found.
	       */
	      size_type
	      size() const noexcept
	      { return _Base_type::empty() ? 0 : _Base_type::size() - 3; }
	
	      size_type
	      max_size() const noexcept
	      { return _Base_type::max_size(); }
	
	      /**
	       * @brief Indicates if the %match_results contains no results.
	       * @retval true The %match_results object is empty.
	       * @retval false The %match_results object is not empty.
	       */
	      _GLIBCXX_NODISCARD bool
	      empty() const noexcept
	      { return size() == 0; }
	
	      //@}
	
	      /**
	       * @name 10.3 Element Access
	       */
	      //@{
	
	      /**
	       * @brief Gets the length of the indicated submatch.
	       * @param __sub indicates the submatch.
	       * @pre   ready() == true
	       *
	       * This function returns the length of the indicated submatch, or the
	       * length of the entire match if @p __sub is zero (the default).
	       */
	      difference_type
	      length(size_type __sub = 0) const
	      { return (*this)[__sub].length(); }
	
	      /**
	       * @brief Gets the offset of the beginning of the indicated submatch.
	       * @param __sub indicates the submatch.
	       * @pre   ready() == true
	       *
	       * This function returns the offset from the beginning of the target
	       * sequence to the beginning of the submatch, unless the value of @p __sub
	       * is zero (the default), in which case this function returns the offset
	       * from the beginning of the target sequence to the beginning of the
	       * match.
	       */
	      difference_type
	      position(size_type __sub = 0) const
	      { return std::distance(_M_begin, (*this)[__sub].first); }
	
	      /**
	       * @brief Gets the match or submatch converted to a string type.
	       * @param __sub indicates the submatch.
	       * @pre   ready() == true
	       *
	       * This function gets the submatch (or match, if @p __sub is
	       * zero) extracted from the target range and converted to the
	       * associated string type.
	       */
	      string_type
	      str(size_type __sub = 0) const
	      { return string_type((*this)[__sub]); }
	
	      /**
	       * @brief Gets a %sub_match reference for the match or submatch.
	       * @param __sub indicates the submatch.
	       * @pre   ready() == true
	       *
	       * This function gets a reference to the indicated submatch, or
	       * the entire match if @p __sub is zero.
	       *
	       * If @p __sub >= size() then this function returns a %sub_match with a
	       * special value indicating no submatch.
	       */
	      const_reference
	      operator[](size_type __sub) const
	      {
		__glibcxx_assert( ready() );
		return __sub < size()
		       ? _Base_type::operator[](__sub)
		       : _M_unmatched_sub();
	      }
	
	      /**
	       * @brief Gets a %sub_match representing the match prefix.
	       * @pre   ready() == true
	       *
	       * This function gets a reference to a %sub_match object representing the
	       * part of the target range between the start of the target range and the
	       * start of the match.
	       */
	      const_reference
	      prefix() const
	      {
		__glibcxx_assert( ready() );
		return !empty() ? _M_prefix() : _M_unmatched_sub();
	      }
	
	      /**
	       * @brief Gets a %sub_match representing the match suffix.
	       * @pre   ready() == true
	       *
	       * This function gets a reference to a %sub_match object representing the
	       * part of the target range between the end of the match and the end of
	       * the target range.
	       */
	      const_reference
	      suffix() const
	      {
		__glibcxx_assert( ready() );
		return !empty() ? _M_suffix() : _M_unmatched_sub();
	      }
	
	      /**
	       * @brief Gets an iterator to the start of the %sub_match collection.
	       */
	      const_iterator
	      begin() const noexcept
	      { return _Base_type::begin(); }
	
	      /**
	       * @brief Gets an iterator to the start of the %sub_match collection.
	       */
	      const_iterator
	      cbegin() const noexcept
	      { return this->begin(); }
	
	      /**
	       * @brief Gets an iterator to one-past-the-end of the collection.
	       */
	      const_iterator
	      end() const noexcept
	      { return _Base_type::end() - (empty() ? 0 : 3); }
	
	      /**
	       * @brief Gets an iterator to one-past-the-end of the collection.
	       */
	      const_iterator
	      cend() const noexcept
	      { return this->end(); }
	
	      //@}
	
	      /**
	       * @name 10.4 Formatting
	       *
	       * These functions perform formatted substitution of the matched
	       * character sequences into their target.  The format specifiers and
	       * escape sequences accepted by these functions are determined by
	       * their @p flags parameter as documented above.
	       */
	       //@{
	
	      /**
	       * @pre   ready() == true
	       */
	      template<typename _Out_iter>
		_Out_iter
		format(_Out_iter __out, const char_type* __fmt_first,
		       const char_type* __fmt_last,
		       match_flag_type __flags = regex_constants::format_default) const;
	
	      /**
	       * @pre   ready() == true
	       */
	      template<typename _Out_iter, typename _St, typename _Sa>
		_Out_iter
		format(_Out_iter __out, const basic_string<char_type, _St, _Sa>& __fmt,
		       match_flag_type __flags = regex_constants::format_default) const
		{
		  return format(__out, __fmt.data(), __fmt.data() + __fmt.size(),
				__flags);
		}
	
	      /**
	       * @pre   ready() == true
	       */
	      template<typename _St, typename _Sa>
		basic_string<char_type, _St, _Sa>
		format(const basic_string<char_type, _St, _Sa>& __fmt,
		       match_flag_type __flags = regex_constants::format_default) const
		{
		  basic_string<char_type, _St, _Sa> __result;
		  format(std::back_inserter(__result), __fmt, __flags);
		  return __result;
		}
	
	      /**
	       * @pre   ready() == true
	       */
	      string_type
	      format(const char_type* __fmt,
		     match_flag_type __flags = regex_constants::format_default) const
	      {
		string_type __result;
		format(std::back_inserter(__result),
		       __fmt,
		       __fmt + char_traits<char_type>::length(__fmt),
		       __flags);
		return __result;
	      }
	
	      //@}
	
	      /**
	       * @name 10.5 Allocator
	       */
	      //@{
	
	      /**
	       * @brief Gets a copy of the allocator.
	       */
	      allocator_type
	      get_allocator() const noexcept
	      { return _Base_type::get_allocator(); }
	
	      //@}
	
	      /**
	       * @name 10.6 Swap
	       */
	       //@{
	
	      /**
	       * @brief Swaps the contents of two match_results.
	       */
	      void
	      swap(match_results& __that) noexcept
	      {
		using std::swap;
		_Base_type::swap(__that);
		swap(_M_begin, __that._M_begin);
	      }
	      //@}
	
	    private:
	      template<typename, typename, typename, bool>
		friend class __detail::_Executor;
	
	      template<typename, typename, typename>
		friend class regex_iterator;
	
	      template<typename _Bp, typename _Ap, typename _Cp, typename _Rp,
		__detail::_RegexExecutorPolicy, bool>
		friend bool
		__detail::__regex_algo_impl(_Bp, _Bp, match_results<_Bp, _Ap>&,
					    const basic_regex<_Cp, _Rp>&,
					    regex_constants::match_flag_type);
	
	      void
	      _M_resize(unsigned int __size)
	      { _Base_type::resize(__size + 3); }
	
	      const_reference
	      _M_unmatched_sub() const
	      { return _Base_type::operator[](_Base_type::size() - 3); }
	
	      sub_match<_Bi_iter>&
	      _M_unmatched_sub()
	      { return _Base_type::operator[](_Base_type::size() - 3); }
	
	      const_reference
	      _M_prefix() const
	      { return _Base_type::operator[](_Base_type::size() - 2); }
	
	      sub_match<_Bi_iter>&
	      _M_prefix()
	      { return _Base_type::operator[](_Base_type::size() - 2); }
	
	      const_reference
	      _M_suffix() const
	      { return _Base_type::operator[](_Base_type::size() - 1); }
	
	      sub_match<_Bi_iter>&
	      _M_suffix()
	      { return _Base_type::operator[](_Base_type::size() - 1); }
	
	      _Bi_iter _M_begin;
	    };
	
	  typedef match_results<const char*>		 cmatch;
	  typedef match_results<string::const_iterator>	 smatch;
	#ifdef _GLIBCXX_USE_WCHAR_T
	  typedef match_results<const wchar_t*>		 wcmatch;
	  typedef match_results<wstring::const_iterator> wsmatch;
	#endif
	
	  // match_results comparisons
	  /**
	   * @brief Compares two match_results for equality.
	   * @returns true if the two objects refer to the same match,
	   * false otherwise.
	   */
	  template<typename _Bi_iter, typename _Alloc>
	    inline bool
	    operator==(const match_results<_Bi_iter, _Alloc>& __m1,
		       const match_results<_Bi_iter, _Alloc>& __m2) noexcept
	    {
	      if (__m1.ready() != __m2.ready())
		return false;
	      if (!__m1.ready())  // both are not ready
		return true;
	      if (__m1.empty() != __m2.empty())
		return false;
	      if (__m1.empty())   // both are empty
		return true;
	      return __m1.prefix() == __m2.prefix()
		&& __m1.size() == __m2.size()
		&& std::equal(__m1.begin(), __m1.end(), __m2.begin())
		&& __m1.suffix() == __m2.suffix();
	    }
	
	  /**
	   * @brief Compares two match_results for inequality.
	   * @returns true if the two objects do not refer to the same match,
	   * false otherwise.
	   */
	  template<typename _Bi_iter, class _Alloc>
	    inline bool
	    operator!=(const match_results<_Bi_iter, _Alloc>& __m1,
		       const match_results<_Bi_iter, _Alloc>& __m2) noexcept
	    { return !(__m1 == __m2); }
	
	  // [7.10.6] match_results swap
	  /**
	   * @brief Swaps two match results.
	   * @param __lhs A match result.
	   * @param __rhs A match result.
	   *
	   * The contents of the two match_results objects are swapped.
	   */
	  template<typename _Bi_iter, typename _Alloc>
	    inline void
	    swap(match_results<_Bi_iter, _Alloc>& __lhs,
		 match_results<_Bi_iter, _Alloc>& __rhs) noexcept
	    { __lhs.swap(__rhs); }
	
	_GLIBCXX_END_NAMESPACE_CXX11
	
	  // [7.11.2] Function template regex_match
	  /**
	   * @name Matching, Searching, and Replacing
	   */
	  //@{
	
	  /**
	   * @brief Determines if there is a match between the regular expression @p e
	   * and all of the character sequence [first, last).
	   *
	   * @param __s     Start of the character sequence to match.
	   * @param __e     One-past-the-end of the character sequence to match.
	   * @param __m     The match results.
	   * @param __re    The regular expression.
	   * @param __flags Controls how the regular expression is matched.
	   *
	   * @retval true  A match exists.
	   * @retval false Otherwise.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Bi_iter, typename _Alloc,
		   typename _Ch_type, typename _Rx_traits>
	    inline bool
	    regex_match(_Bi_iter				 __s,
			_Bi_iter				 __e,
			match_results<_Bi_iter, _Alloc>&	 __m,
			const basic_regex<_Ch_type, _Rx_traits>& __re,
			regex_constants::match_flag_type	 __flags
				       = regex_constants::match_default)
	    {
	      return __detail::__regex_algo_impl<_Bi_iter, _Alloc, _Ch_type, _Rx_traits,
		__detail::_RegexExecutorPolicy::_S_auto, true>
		  (__s, __e, __m, __re, __flags);
	    }
	
	  /**
	   * @brief Indicates if there is a match between the regular expression @p e
	   * and all of the character sequence [first, last).
	   *
	   * @param __first Beginning of the character sequence to match.
	   * @param __last  One-past-the-end of the character sequence to match.
	   * @param __re    The regular expression.
	   * @param __flags Controls how the regular expression is matched.
	   *
	   * @retval true  A match exists.
	   * @retval false Otherwise.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Bi_iter, typename _Ch_type, typename _Rx_traits>
	    inline bool
	    regex_match(_Bi_iter __first, _Bi_iter __last,
			const basic_regex<_Ch_type, _Rx_traits>& __re,
			regex_constants::match_flag_type __flags
			= regex_constants::match_default)
	    {
	      match_results<_Bi_iter> __what;
	      return regex_match(__first, __last, __what, __re, __flags);
	    }
	
	  /**
	   * @brief Determines if there is a match between the regular expression @p e
	   * and a C-style null-terminated string.
	   *
	   * @param __s  The C-style null-terminated string to match.
	   * @param __m  The match results.
	   * @param __re The regular expression.
	   * @param __f  Controls how the regular expression is matched.
	   *
	   * @retval true  A match exists.
	   * @retval false Otherwise.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Ch_type, typename _Alloc, typename _Rx_traits>
	    inline bool
	    regex_match(const _Ch_type* __s,
			match_results<const _Ch_type*, _Alloc>& __m,
			const basic_regex<_Ch_type, _Rx_traits>& __re,
			regex_constants::match_flag_type __f
			= regex_constants::match_default)
	    { return regex_match(__s, __s + _Rx_traits::length(__s), __m, __re, __f); }
	
	  /**
	   * @brief Determines if there is a match between the regular expression @p e
	   * and a string.
	   *
	   * @param __s     The string to match.
	   * @param __m     The match results.
	   * @param __re    The regular expression.
	   * @param __flags Controls how the regular expression is matched.
	   *
	   * @retval true  A match exists.
	   * @retval false Otherwise.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Ch_traits, typename _Ch_alloc,
		   typename _Alloc, typename _Ch_type, typename _Rx_traits>
	    inline bool
	    regex_match(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>& __s,
			match_results<typename basic_string<_Ch_type,
			_Ch_traits, _Ch_alloc>::const_iterator, _Alloc>& __m,
			const basic_regex<_Ch_type, _Rx_traits>& __re,
			regex_constants::match_flag_type __flags
			= regex_constants::match_default)
	    { return regex_match(__s.begin(), __s.end(), __m, __re, __flags); }
	
	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
	  // 2329. regex_match() with match_results should forbid temporary strings
	  /// Prevent unsafe attempts to get match_results from a temporary string.
	  template<typename _Ch_traits, typename _Ch_alloc,
		   typename _Alloc, typename _Ch_type, typename _Rx_traits>
	    bool
	    regex_match(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>&&,
			match_results<typename basic_string<_Ch_type,
			_Ch_traits, _Ch_alloc>::const_iterator, _Alloc>&,
			const basic_regex<_Ch_type, _Rx_traits>&,
			regex_constants::match_flag_type
			= regex_constants::match_default) = delete;
	
	  /**
	   * @brief Indicates if there is a match between the regular expression @p e
	   * and a C-style null-terminated string.
	   *
	   * @param __s  The C-style null-terminated string to match.
	   * @param __re The regular expression.
	   * @param __f  Controls how the regular expression is matched.
	   *
	   * @retval true  A match exists.
	   * @retval false Otherwise.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Ch_type, class _Rx_traits>
	    inline bool
	    regex_match(const _Ch_type* __s,
			const basic_regex<_Ch_type, _Rx_traits>& __re,
			regex_constants::match_flag_type __f
			= regex_constants::match_default)
	    { return regex_match(__s, __s + _Rx_traits::length(__s), __re, __f); }
	
	  /**
	   * @brief Indicates if there is a match between the regular expression @p e
	   * and a string.
	   *
	   * @param __s     [IN] The string to match.
	   * @param __re    [IN] The regular expression.
	   * @param __flags [IN] Controls how the regular expression is matched.
	   *
	   * @retval true  A match exists.
	   * @retval false Otherwise.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Ch_traits, typename _Str_allocator,
		   typename _Ch_type, typename _Rx_traits>
	    inline bool
	    regex_match(const basic_string<_Ch_type, _Ch_traits, _Str_allocator>& __s,
			const basic_regex<_Ch_type, _Rx_traits>& __re,
			regex_constants::match_flag_type __flags
			= regex_constants::match_default)
	    { return regex_match(__s.begin(), __s.end(), __re, __flags); }
	
	  // [7.11.3] Function template regex_search
	  /**
	   * Searches for a regular expression within a range.
	   * @param __s     [IN]  The start of the string to search.
	   * @param __e     [IN]  One-past-the-end of the string to search.
	   * @param __m     [OUT] The match results.
	   * @param __re    [IN]  The regular expression to search for.
	   * @param __flags [IN]  Search policy flags.
	   * @retval true  A match was found within the string.
	   * @retval false No match was found within the string, the content of %m is
	   *               undefined.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Bi_iter, typename _Alloc,
		   typename _Ch_type, typename _Rx_traits>
	    inline bool
	    regex_search(_Bi_iter __s, _Bi_iter __e,
			 match_results<_Bi_iter, _Alloc>& __m,
			 const basic_regex<_Ch_type, _Rx_traits>& __re,
			 regex_constants::match_flag_type __flags
			 = regex_constants::match_default)
	    {
	      return __detail::__regex_algo_impl<_Bi_iter, _Alloc, _Ch_type, _Rx_traits,
		__detail::_RegexExecutorPolicy::_S_auto, false>
		  (__s, __e, __m, __re, __flags);
	    }
	
	  /**
	   * Searches for a regular expression within a range.
	   * @param __first [IN]  The start of the string to search.
	   * @param __last  [IN]  One-past-the-end of the string to search.
	   * @param __re    [IN]  The regular expression to search for.
	   * @param __flags [IN]  Search policy flags.
	   * @retval true  A match was found within the string.
	   * @retval false No match was found within the string.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Bi_iter, typename _Ch_type, typename _Rx_traits>
	    inline bool
	    regex_search(_Bi_iter __first, _Bi_iter __last,
			 const basic_regex<_Ch_type, _Rx_traits>& __re,
			 regex_constants::match_flag_type __flags
			 = regex_constants::match_default)
	    {
	      match_results<_Bi_iter> __what;
	      return regex_search(__first, __last, __what, __re, __flags);
	    }
	
	  /**
	   * @brief Searches for a regular expression within a C-string.
	   * @param __s [IN]  A C-string to search for the regex.
	   * @param __m [OUT] The set of regex matches.
	   * @param __e [IN]  The regex to search for in @p s.
	   * @param __f [IN]  The search flags.
	   * @retval true  A match was found within the string.
	   * @retval false No match was found within the string, the content of %m is
	   *               undefined.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Ch_type, class _Alloc, class _Rx_traits>
	    inline bool
	    regex_search(const _Ch_type* __s,
			 match_results<const _Ch_type*, _Alloc>& __m,
			 const basic_regex<_Ch_type, _Rx_traits>& __e,
			 regex_constants::match_flag_type __f
			 = regex_constants::match_default)
	    { return regex_search(__s, __s + _Rx_traits::length(__s), __m, __e, __f); }
	
	  /**
	   * @brief Searches for a regular expression within a C-string.
	   * @param __s [IN]  The C-string to search.
	   * @param __e [IN]  The regular expression to search for.
	   * @param __f [IN]  Search policy flags.
	   * @retval true  A match was found within the string.
	   * @retval false No match was found within the string.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Ch_type, typename _Rx_traits>
	    inline bool
	    regex_search(const _Ch_type* __s,
			 const basic_regex<_Ch_type, _Rx_traits>& __e,
			 regex_constants::match_flag_type __f
			 = regex_constants::match_default)
	    { return regex_search(__s, __s + _Rx_traits::length(__s), __e, __f); }
	
	  /**
	   * @brief Searches for a regular expression within a string.
	   * @param __s     [IN]  The string to search.
	   * @param __e     [IN]  The regular expression to search for.
	   * @param __flags [IN]  Search policy flags.
	   * @retval true  A match was found within the string.
	   * @retval false No match was found within the string.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Ch_traits, typename _String_allocator,
		   typename _Ch_type, typename _Rx_traits>
	    inline bool
	    regex_search(const basic_string<_Ch_type, _Ch_traits,
			 _String_allocator>& __s,
			 const basic_regex<_Ch_type, _Rx_traits>& __e,
			 regex_constants::match_flag_type __flags
			 = regex_constants::match_default)
	    { return regex_search(__s.begin(), __s.end(), __e, __flags); }
	
	  /**
	   * @brief Searches for a regular expression within a string.
	   * @param __s [IN]  A C++ string to search for the regex.
	   * @param __m [OUT] The set of regex matches.
	   * @param __e [IN]  The regex to search for in @p s.
	   * @param __f [IN]  The search flags.
	   * @retval true  A match was found within the string.
	   * @retval false No match was found within the string, the content of %m is
	   *               undefined.
	   *
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Ch_traits, typename _Ch_alloc,
		   typename _Alloc, typename _Ch_type,
		   typename _Rx_traits>
	    inline bool
	    regex_search(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>& __s,
			 match_results<typename basic_string<_Ch_type,
			 _Ch_traits, _Ch_alloc>::const_iterator, _Alloc>& __m,
			 const basic_regex<_Ch_type, _Rx_traits>& __e,
			 regex_constants::match_flag_type __f
			 = regex_constants::match_default)
	    { return regex_search(__s.begin(), __s.end(), __m, __e, __f); }
	
	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
	  // 2329. regex_search() with match_results should forbid temporary strings
	  /// Prevent unsafe attempts to get match_results from a temporary string.
	  template<typename _Ch_traits, typename _Ch_alloc,
		   typename _Alloc, typename _Ch_type,
		   typename _Rx_traits>
	    bool
	    regex_search(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>&&,
			 match_results<typename basic_string<_Ch_type,
			 _Ch_traits, _Ch_alloc>::const_iterator, _Alloc>&,
			 const basic_regex<_Ch_type, _Rx_traits>&,
			 regex_constants::match_flag_type
			 = regex_constants::match_default) = delete;
	
	  // std [28.11.4] Function template regex_replace
	  /**
	   * @brief Search for a regular expression within a range for multiple times,
	   and replace the matched parts through filling a format string.
	   * @param __out   [OUT] The output iterator.
	   * @param __first [IN]  The start of the string to search.
	   * @param __last  [IN]  One-past-the-end of the string to search.
	   * @param __e     [IN]  The regular expression to search for.
	   * @param __fmt   [IN]  The format string.
	   * @param __flags [IN]  Search and replace policy flags.
	   *
	   * @returns __out
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Out_iter, typename _Bi_iter,
		   typename _Rx_traits, typename _Ch_type,
		   typename _St, typename _Sa>
	    inline _Out_iter
	    regex_replace(_Out_iter __out, _Bi_iter __first, _Bi_iter __last,
			  const basic_regex<_Ch_type, _Rx_traits>& __e,
			  const basic_string<_Ch_type, _St, _Sa>& __fmt,
			  regex_constants::match_flag_type __flags
			  = regex_constants::match_default)
	    {
	      return regex_replace(__out, __first, __last, __e, __fmt.c_str(), __flags);
	    }
	
	  /**
	   * @brief Search for a regular expression within a range for multiple times,
	   and replace the matched parts through filling a format C-string.
	   * @param __out   [OUT] The output iterator.
	   * @param __first [IN]  The start of the string to search.
	   * @param __last  [IN]  One-past-the-end of the string to search.
	   * @param __e     [IN]  The regular expression to search for.
	   * @param __fmt   [IN]  The format C-string.
	   * @param __flags [IN]  Search and replace policy flags.
	   *
	   * @returns __out
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Out_iter, typename _Bi_iter,
		   typename _Rx_traits, typename _Ch_type>
	    _Out_iter
	    regex_replace(_Out_iter __out, _Bi_iter __first, _Bi_iter __last,
			  const basic_regex<_Ch_type, _Rx_traits>& __e,
			  const _Ch_type* __fmt,
			  regex_constants::match_flag_type __flags
			  = regex_constants::match_default);
	
	  /**
	   * @brief Search for a regular expression within a string for multiple times,
	   and replace the matched parts through filling a format string.
	   * @param __s     [IN] The string to search and replace.
	   * @param __e     [IN] The regular expression to search for.
	   * @param __fmt   [IN] The format string.
	   * @param __flags [IN] Search and replace policy flags.
	   *
	   * @returns The string after replacing.
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Rx_traits, typename _Ch_type,
		   typename _St, typename _Sa, typename _Fst, typename _Fsa>
	    inline basic_string<_Ch_type, _St, _Sa>
	    regex_replace(const basic_string<_Ch_type, _St, _Sa>& __s,
			  const basic_regex<_Ch_type, _Rx_traits>& __e,
			  const basic_string<_Ch_type, _Fst, _Fsa>& __fmt,
			  regex_constants::match_flag_type __flags
			  = regex_constants::match_default)
	    {
	      basic_string<_Ch_type, _St, _Sa> __result;
	      regex_replace(std::back_inserter(__result),
			    __s.begin(), __s.end(), __e, __fmt, __flags);
	      return __result;
	    }
	
	  /**
	   * @brief Search for a regular expression within a string for multiple times,
	   and replace the matched parts through filling a format C-string.
	   * @param __s     [IN] The string to search and replace.
	   * @param __e     [IN] The regular expression to search for.
	   * @param __fmt   [IN] The format C-string.
	   * @param __flags [IN] Search and replace policy flags.
	   *
	   * @returns The string after replacing.
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Rx_traits, typename _Ch_type,
		   typename _St, typename _Sa>
	    inline basic_string<_Ch_type, _St, _Sa>
	    regex_replace(const basic_string<_Ch_type, _St, _Sa>& __s,
			  const basic_regex<_Ch_type, _Rx_traits>& __e,
			  const _Ch_type* __fmt,
			  regex_constants::match_flag_type __flags
			  = regex_constants::match_default)
	    {
	      basic_string<_Ch_type, _St, _Sa> __result;
	      regex_replace(std::back_inserter(__result),
			    __s.begin(), __s.end(), __e, __fmt, __flags);
	      return __result;
	    }
	
	  /**
	   * @brief Search for a regular expression within a C-string for multiple
	   times, and replace the matched parts through filling a format string.
	   * @param __s     [IN] The C-string to search and replace.
	   * @param __e     [IN] The regular expression to search for.
	   * @param __fmt   [IN] The format string.
	   * @param __flags [IN] Search and replace policy flags.
	   *
	   * @returns The string after replacing.
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Rx_traits, typename _Ch_type,
		   typename _St, typename _Sa>
	    inline basic_string<_Ch_type>
	    regex_replace(const _Ch_type* __s,
			  const basic_regex<_Ch_type, _Rx_traits>& __e,
			  const basic_string<_Ch_type, _St, _Sa>& __fmt,
			  regex_constants::match_flag_type __flags
			  = regex_constants::match_default)
	    {
	      basic_string<_Ch_type> __result;
	      regex_replace(std::back_inserter(__result), __s,
			    __s + char_traits<_Ch_type>::length(__s),
			    __e, __fmt, __flags);
	      return __result;
	    }
	
	  /**
	   * @brief Search for a regular expression within a C-string for multiple
	   times, and replace the matched parts through filling a format C-string.
	   * @param __s     [IN] The C-string to search and replace.
	   * @param __e     [IN] The regular expression to search for.
	   * @param __fmt   [IN] The format C-string.
	   * @param __flags [IN] Search and replace policy flags.
	   *
	   * @returns The string after replacing.
	   * @throws an exception of type regex_error.
	   */
	  template<typename _Rx_traits, typename _Ch_type>
	    inline basic_string<_Ch_type>
	    regex_replace(const _Ch_type* __s,
			  const basic_regex<_Ch_type, _Rx_traits>& __e,
			  const _Ch_type* __fmt,
			  regex_constants::match_flag_type __flags
			  = regex_constants::match_default)
	    {
	      basic_string<_Ch_type> __result;
	      regex_replace(std::back_inserter(__result), __s,
			    __s + char_traits<_Ch_type>::length(__s),
			    __e, __fmt, __flags);
	      return __result;
	    }
	
	  //@}
	
	_GLIBCXX_BEGIN_NAMESPACE_CXX11
	
	  // std [28.12] Class template regex_iterator
	  /**
	   * An iterator adaptor that will provide repeated calls of regex_search over
	   * a range until no more matches remain.
	   */
	  template<typename _Bi_iter,
		   typename _Ch_type = typename iterator_traits<_Bi_iter>::value_type,
		   typename _Rx_traits = regex_traits<_Ch_type> >
	    class regex_iterator
	    {
	    public:
	      typedef basic_regex<_Ch_type, _Rx_traits>  regex_type;
	      typedef match_results<_Bi_iter>	    value_type;
	      typedef std::ptrdiff_t		     difference_type;
	      typedef const value_type*		  pointer;
	      typedef const value_type&		  reference;
	      typedef std::forward_iterator_tag	  iterator_category;
	
	      /**
	       * @brief Provides a singular iterator, useful for indicating
	       * one-past-the-end of a range.
	       */
	      regex_iterator() = default;
	
	      /**
	       * Constructs a %regex_iterator...
	       * @param __a  [IN] The start of a text range to search.
	       * @param __b  [IN] One-past-the-end of the text range to search.
	       * @param __re [IN] The regular expression to match.
	       * @param __m  [IN] Policy flags for match rules.
	       */
	      regex_iterator(_Bi_iter __a, _Bi_iter __b, const regex_type& __re,
			     regex_constants::match_flag_type __m
			     = regex_constants::match_default)
	      : _M_begin(__a), _M_end(__b), _M_pregex(&__re), _M_flags(__m), _M_match()
	      {
		if (!regex_search(_M_begin, _M_end, _M_match, *_M_pregex, _M_flags))
		  *this = regex_iterator();
	      }
	
	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
	      // 2332. regex_iterator should forbid temporary regexes
	      regex_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
			     regex_constants::match_flag_type
			     = regex_constants::match_default) = delete;
	
	      /// Copy constructs a %regex_iterator.
	      regex_iterator(const regex_iterator&) = default;
	
	      /// Copy assigns one %regex_iterator to another.
	      regex_iterator&
	      operator=(const regex_iterator&) = default;
	
	      ~regex_iterator() = default;
	
	      /**
	       * @brief Tests the equivalence of two regex iterators.
	       */
	      bool
	      operator==(const regex_iterator&) const noexcept;
	
	      /**
	       * @brief Tests the inequivalence of two regex iterators.
	       */
	      bool
	      operator!=(const regex_iterator& __rhs) const noexcept
	      { return !(*this == __rhs); }
	
	      /**
	       * @brief Dereferences a %regex_iterator.
	       */
	      const value_type&
	      operator*() const noexcept
	      { return _M_match; }
	
	      /**
	       * @brief Selects a %regex_iterator member.
	       */
	      const value_type*
	      operator->() const noexcept
	      { return &_M_match; }
	
	      /**
	       * @brief Increments a %regex_iterator.
	       */
	      regex_iterator&
	      operator++();
	
	      /**
	       * @brief Postincrements a %regex_iterator.
	       */
	      regex_iterator
	      operator++(int)
	      {
		auto __tmp = *this;
		++(*this);
		return __tmp;
	      }
	
	    private:
	      _Bi_iter				_M_begin {};
	      _Bi_iter				_M_end {};
	      const regex_type*			_M_pregex = nullptr;
	      regex_constants::match_flag_type	_M_flags {};
	      match_results<_Bi_iter>		_M_match;
	    };
	
	  typedef regex_iterator<const char*>			cregex_iterator;
	  typedef regex_iterator<string::const_iterator>	sregex_iterator;
	#ifdef _GLIBCXX_USE_WCHAR_T
	  typedef regex_iterator<const wchar_t*>		wcregex_iterator;
	  typedef regex_iterator<wstring::const_iterator>	wsregex_iterator;
	#endif
	
	  // [7.12.2] Class template regex_token_iterator
	  /**
	   * Iterates over submatches in a range (or @a splits a text string).
	   *
	   * The purpose of this iterator is to enumerate all, or all specified,
	   * matches of a regular expression within a text range.  The dereferenced
	   * value of an iterator of this class is a std::sub_match object.
	   */
	  template<typename _Bi_iter,
		   typename _Ch_type = typename iterator_traits<_Bi_iter>::value_type,
		   typename _Rx_traits = regex_traits<_Ch_type> >
	    class regex_token_iterator
	    {
	    public:
	      typedef basic_regex<_Ch_type, _Rx_traits>	regex_type;
	      typedef sub_match<_Bi_iter>		value_type;
	      typedef std::ptrdiff_t			difference_type;
	      typedef const value_type*			pointer;
	      typedef const value_type&			reference;
	      typedef std::forward_iterator_tag		iterator_category;
	
	    public:
	      /**
	       * @brief Default constructs a %regex_token_iterator.
	       *
	       * A default-constructed %regex_token_iterator is a singular iterator
	       * that will compare equal to the one-past-the-end value for any
	       * iterator of the same type.
	       */
	      regex_token_iterator()
	      : _M_position(), _M_subs(), _M_suffix(), _M_n(0), _M_result(nullptr),
	      _M_has_m1(false)
	      { }
	
	      /**
	       * Constructs a %regex_token_iterator...
	       * @param __a          [IN] The start of the text to search.
	       * @param __b          [IN] One-past-the-end of the text to search.
	       * @param __re         [IN] The regular expression to search for.
	       * @param __submatch   [IN] Which submatch to return.  There are some
	       *                        special values for this parameter:
	       *                        - -1 each enumerated subexpression does NOT
	       *                          match the regular expression (aka field
	       *                          splitting)
	       *                        - 0 the entire string matching the
	       *                          subexpression is returned for each match
	       *                          within the text.
	       *                        - >0 enumerates only the indicated
	       *                          subexpression from a match within the text.
	       * @param __m          [IN] Policy flags for match rules.
	       */
	      regex_token_iterator(_Bi_iter __a, _Bi_iter __b, const regex_type& __re,
				   int __submatch = 0,
				   regex_constants::match_flag_type __m
				   = regex_constants::match_default)
	      : _M_position(__a, __b, __re, __m), _M_subs(1, __submatch), _M_n(0)
	      { _M_init(__a, __b); }
	
	      /**
	       * Constructs a %regex_token_iterator...
	       * @param __a          [IN] The start of the text to search.
	       * @param __b          [IN] One-past-the-end of the text to search.
	       * @param __re         [IN] The regular expression to search for.
	       * @param __submatches [IN] A list of subexpressions to return for each
	       *                          regular expression match within the text.
	       * @param __m          [IN] Policy flags for match rules.
	       */
	      regex_token_iterator(_Bi_iter __a, _Bi_iter __b,
				   const regex_type& __re,
				   const std::vector<int>& __submatches,
				   regex_constants::match_flag_type __m
				     = regex_constants::match_default)
	      : _M_position(__a, __b, __re, __m), _M_subs(__submatches), _M_n(0)
	      { _M_init(__a, __b); }
	
	      /**
	       * Constructs a %regex_token_iterator...
	       * @param __a          [IN] The start of the text to search.
	       * @param __b          [IN] One-past-the-end of the text to search.
	       * @param __re         [IN] The regular expression to search for.
	       * @param __submatches [IN] A list of subexpressions to return for each
	       *                          regular expression match within the text.
	       * @param __m          [IN] Policy flags for match rules.
	       */
	      regex_token_iterator(_Bi_iter __a, _Bi_iter __b,
				   const regex_type& __re,
				   initializer_list<int> __submatches,
				   regex_constants::match_flag_type __m
				     = regex_constants::match_default)
	      : _M_position(__a, __b, __re, __m), _M_subs(__submatches), _M_n(0)
	      { _M_init(__a, __b); }
	
	      /**
	       * Constructs a %regex_token_iterator...
	       * @param __a          [IN] The start of the text to search.
	       * @param __b          [IN] One-past-the-end of the text to search.
	       * @param __re         [IN] The regular expression to search for.
	       * @param __submatches [IN] A list of subexpressions to return for each
	       *                          regular expression match within the text.
	       * @param __m          [IN] Policy flags for match rules.
	       */
	      template<std::size_t _Nm>
		regex_token_iterator(_Bi_iter __a, _Bi_iter __b,
				     const regex_type& __re,
				     const int (&__submatches)[_Nm],
				     regex_constants::match_flag_type __m
				     = regex_constants::match_default)
	      : _M_position(__a, __b, __re, __m),
	      _M_subs(__submatches, __submatches + _Nm), _M_n(0)
	      { _M_init(__a, __b); }
	
	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
	      // 2332. regex_token_iterator should forbid temporary regexes
	      regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&, int = 0,
				   regex_constants::match_flag_type =
				   regex_constants::match_default) = delete;
	      regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
				   const std::vector<int>&,
				   regex_constants::match_flag_type =
				   regex_constants::match_default) = delete;
	      regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
				   initializer_list<int>,
				   regex_constants::match_flag_type =
				   regex_constants::match_default) = delete;
	      template <std::size_t _Nm>
		regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
				     const int (&)[_Nm],
				     regex_constants::match_flag_type =
				     regex_constants::match_default) = delete;
	
	      /**
	       * @brief Copy constructs a %regex_token_iterator.
	       * @param __rhs [IN] A %regex_token_iterator to copy.
	       */
	      regex_token_iterator(const regex_token_iterator& __rhs)
	      : _M_position(__rhs._M_position), _M_subs(__rhs._M_subs),
	      _M_suffix(__rhs._M_suffix), _M_n(__rhs._M_n), _M_has_m1(__rhs._M_has_m1)
	      { _M_normalize_result(); }
	
	      /**
	       * @brief Assigns a %regex_token_iterator to another.
	       * @param __rhs [IN] A %regex_token_iterator to copy.
	       */
	      regex_token_iterator&
	      operator=(const regex_token_iterator& __rhs);
	
	      /**
	       * @brief Compares a %regex_token_iterator to another for equality.
	       */
	      bool
	      operator==(const regex_token_iterator& __rhs) const;
	
	      /**
	       * @brief Compares a %regex_token_iterator to another for inequality.
	       */
	      bool
	      operator!=(const regex_token_iterator& __rhs) const
	      { return !(*this == __rhs); }
	
	      /**
	       * @brief Dereferences a %regex_token_iterator.
	       */
	      const value_type&
	      operator*() const
	      { return *_M_result; }
	
	      /**
	       * @brief Selects a %regex_token_iterator member.
	       */
	      const value_type*
	      operator->() const
	      { return _M_result; }
	
	      /**
	       * @brief Increments a %regex_token_iterator.
	       */
	      regex_token_iterator&
	      operator++();
	
	      /**
	       * @brief Postincrements a %regex_token_iterator.
	       */
	      regex_token_iterator
	      operator++(int)
	      {
		auto __tmp = *this;
		++(*this);
		return __tmp;
	      }
	
	    private:
	      typedef regex_iterator<_Bi_iter, _Ch_type, _Rx_traits> _Position;
	
	      void
	      _M_init(_Bi_iter __a, _Bi_iter __b);
	
	      const value_type&
	      _M_current_match() const
	      {
		if (_M_subs[_M_n] == -1)
		  return (*_M_position).prefix();
		else
		  return (*_M_position)[_M_subs[_M_n]];
	      }
	
	      constexpr bool
	      _M_end_of_seq() const
	      { return _M_result == nullptr; }
	
	      // [28.12.2.2.4]
	      void
	      _M_normalize_result()
	      {
		if (_M_position != _Position())
		  _M_result = &_M_current_match();
		else if (_M_has_m1)
		  _M_result = &_M_suffix;
		else
		  _M_result = nullptr;
	      }
	
	      _Position		_M_position;
	      std::vector<int>	_M_subs;
	      value_type	_M_suffix;
	      std::size_t	_M_n;
	      const value_type*	_M_result;
	
	      // Show whether _M_subs contains -1
	      bool		_M_has_m1;
	    };
	
	  /** @brief Token iterator for C-style NULL-terminated strings. */
	  typedef regex_token_iterator<const char*>		cregex_token_iterator;
	
	  /** @brief Token iterator for standard strings. */
	  typedef regex_token_iterator<string::const_iterator>	sregex_token_iterator;
	
	#ifdef _GLIBCXX_USE_WCHAR_T
	  /** @brief Token iterator for C-style NULL-terminated wide strings. */
	  typedef regex_token_iterator<const wchar_t*>		wcregex_token_iterator;
	
	  /** @brief Token iterator for standard wide-character strings. */
	  typedef regex_token_iterator<wstring::const_iterator> wsregex_token_iterator;
	#endif
	
	  //@} // group regex
	
	_GLIBCXX_END_NAMESPACE_CXX11
	_GLIBCXX_END_NAMESPACE_VERSION
	} // namespace
	
	#include <bits/regex.tcc>