ce796131e1
2007-11-08 Paolo Carlini <pcarlini@suse.de> * include/std/type_traits (__decay_selector<_Up, false, false>): Change according to DR 705. * include/bits/stl_pair.h (make_pair(_T1&&, _T2&&)): Change according to DR 706. * include/tr1_impl/tuple: Tweak. From-SVN: r130001
258 lines
8.2 KiB
C++
258 lines
8.2 KiB
C++
// Pair implementation -*- C++ -*-
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// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
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// Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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/*
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*
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* Copyright (c) 1994
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* Hewlett-Packard Company
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Hewlett-Packard Company makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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*
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* Copyright (c) 1996,1997
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* Silicon Graphics Computer Systems, Inc.
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Silicon Graphics makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*/
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/** @file stl_pair.h
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* This is an internal header file, included by other library headers.
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* You should not attempt to use it directly.
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*/
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#ifndef _STL_PAIR_H
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#define _STL_PAIR_H 1
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#include <bits/stl_move.h> // for std::move / std::forward, std::decay, and
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// std::swap
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_GLIBCXX_BEGIN_NAMESPACE(std)
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/// pair holds two objects of arbitrary type.
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template<class _T1, class _T2>
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struct pair
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{
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typedef _T1 first_type; ///< @c first_type is the first bound type
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typedef _T2 second_type; ///< @c second_type is the second bound type
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_T1 first; ///< @c first is a copy of the first object
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_T2 second; ///< @c second is a copy of the second object
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// 265. std::pair::pair() effects overly restrictive
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/** The default constructor creates @c first and @c second using their
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* respective default constructors. */
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pair()
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: first(), second() { }
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/** Two objects may be passed to a @c pair constructor to be copied. */
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pair(const _T1& __a, const _T2& __b)
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: first(__a), second(__b) { }
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#ifdef __GXX_EXPERIMENTAL_CXX0X__
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template<class _U1, class _U2>
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pair(_U1&& __x, _U2&& __y)
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: first(std::forward<_U1>(__x)),
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second(std::forward<_U2>(__y)) { }
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pair(pair&& __p)
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: first(std::move(__p.first)),
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second(std::move(__p.second)) { }
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#endif
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/** There is also a templated copy ctor for the @c pair class itself. */
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template<class _U1, class _U2>
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pair(const pair<_U1, _U2>& __p)
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: first(__p.first),
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second(__p.second) { }
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#ifdef __GXX_EXPERIMENTAL_CXX0X__
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template<class _U1, class _U2>
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pair(pair<_U1, _U2>&& __p)
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: first(std::move(__p.first)),
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second(std::move(__p.second)) { }
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pair&
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operator=(pair&& __p)
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{
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first = std::move(__p.first);
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second = std::move(__p.second);
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return *this;
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}
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template<class _U1, class _U2>
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pair&
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operator=(pair<_U1, _U2>&& __p)
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{
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first = std::move(__p.first);
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second = std::move(__p.second);
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return *this;
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}
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void
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swap(pair&& __p)
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{
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using std::swap;
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swap(first, __p.first);
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swap(second, __p.second);
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}
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#endif
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};
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/// Two pairs of the same type are equal iff their members are equal.
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template<class _T1, class _T2>
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inline bool
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operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return __x.first == __y.first && __x.second == __y.second; }
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/// <http://gcc.gnu.org/onlinedocs/libstdc++/20_util/howto.html#pairlt>
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template<class _T1, class _T2>
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inline bool
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operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return __x.first < __y.first
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|| (!(__y.first < __x.first) && __x.second < __y.second); }
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/// Uses @c operator== to find the result.
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template<class _T1, class _T2>
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inline bool
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operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return !(__x == __y); }
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/// Uses @c operator< to find the result.
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template<class _T1, class _T2>
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inline bool
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operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return __y < __x; }
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/// Uses @c operator< to find the result.
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template<class _T1, class _T2>
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inline bool
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operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return !(__y < __x); }
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/// Uses @c operator< to find the result.
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template<class _T1, class _T2>
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inline bool
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operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return !(__x < __y); }
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#ifdef __GXX_EXPERIMENTAL_CXX0X__
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/// See std::pair::swap().
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template<class _T1, class _T2>
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inline void
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swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
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{ __x.swap(__y); }
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template<class _T1, class _T2>
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inline void
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swap(pair<_T1, _T2>&& __x, pair<_T1, _T2>& __y)
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{ __x.swap(__y); }
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template<class _T1, class _T2>
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inline void
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swap(pair<_T1, _T2>& __x, pair<_T1, _T2>&& __y)
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{ __x.swap(__y); }
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#endif
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/**
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* @brief A convenience wrapper for creating a pair from two objects.
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* @param x The first object.
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* @param y The second object.
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* @return A newly-constructed pair<> object of the appropriate type.
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*
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* The standard requires that the objects be passed by reference-to-const,
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* but LWG issue #181 says they should be passed by const value. We follow
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* the LWG by default.
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*/
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// 181. make_pair() unintended behavior
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#ifndef __GXX_EXPERIMENTAL_CXX0X__
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template<class _T1, class _T2>
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inline pair<_T1, _T2>
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make_pair(_T1 __x, _T2 __y)
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{ return pair<_T1, _T2>(__x, __y); }
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#else
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template<typename _Tp>
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class reference_wrapper;
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// Helper which adds a reference to a type when given a reference_wrapper
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template<typename _Tp>
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struct __strip_reference_wrapper
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{
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typedef _Tp __type;
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};
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template<typename _Tp>
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struct __strip_reference_wrapper<reference_wrapper<_Tp> >
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{
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typedef _Tp& __type;
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};
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template<typename _Tp>
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struct __strip_reference_wrapper<const reference_wrapper<_Tp> >
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{
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typedef _Tp& __type;
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};
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template<typename _Tp>
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struct __decay_and_strip
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{
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typedef typename __strip_reference_wrapper<
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typename decay<_Tp>::type>::__type __type;
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};
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// NB: DR 706.
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template<class _T1, class _T2>
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inline pair<typename __decay_and_strip<_T1>::__type,
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typename __decay_and_strip<_T2>::__type>
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make_pair(_T1&& __x, _T2&& __y)
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{
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return pair<typename __decay_and_strip<_T1>::__type,
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typename __decay_and_strip<_T2>::__type>
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(std::forward<_T1>(__x), std::forward<_T2>(__y));
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}
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#endif
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_GLIBCXX_END_NAMESPACE
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#endif /* _STL_PAIR_H */
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