566 lines
17 KiB
C++
566 lines
17 KiB
C++
// shared_ptr and weak_ptr implementation -*- C++ -*-
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// Copyright (C) 2007, 2008, 2009, 2010, 2011 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 3, 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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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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// GCC Note: Based on files from version 1.32.0 of the Boost library.
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// shared_count.hpp
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// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
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// shared_ptr.hpp
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// Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.
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// Copyright (C) 2001, 2002, 2003 Peter Dimov
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// weak_ptr.hpp
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// Copyright (C) 2001, 2002, 2003 Peter Dimov
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// enable_shared_from_this.hpp
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// Copyright (C) 2002 Peter Dimov
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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/** @file bits/shared_ptr.h
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* This is an internal header file, included by other library headers.
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* Do not attempt to use it directly. @headername{memory}
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*/
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#ifndef _SHARED_PTR_H
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#define _SHARED_PTR_H 1
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#include <bits/shared_ptr_base.h>
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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/**
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* @addtogroup pointer_abstractions
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* @{
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*/
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/// 2.2.3.7 shared_ptr I/O
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template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy _Lp>
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inline std::basic_ostream<_Ch, _Tr>&
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operator<<(std::basic_ostream<_Ch, _Tr>& __os,
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const __shared_ptr<_Tp, _Lp>& __p)
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{
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__os << __p.get();
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return __os;
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}
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/// 2.2.3.10 shared_ptr get_deleter (experimental)
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template<typename _Del, typename _Tp, _Lock_policy _Lp>
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inline _Del*
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get_deleter(const __shared_ptr<_Tp, _Lp>& __p)
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{
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#ifdef __GXX_RTTI
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return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del)));
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#else
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return 0;
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#endif
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}
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/**
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* @brief A smart pointer with reference-counted copy semantics.
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*
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* The object pointed to is deleted when the last shared_ptr pointing to
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* it is destroyed or reset.
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*/
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template<typename _Tp>
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class shared_ptr : public __shared_ptr<_Tp>
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{
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public:
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/**
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* @brief Construct an empty %shared_ptr.
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* @post use_count()==0 && get()==0
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*/
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constexpr shared_ptr()
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: __shared_ptr<_Tp>() { }
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/**
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* @brief Construct a %shared_ptr that owns the pointer @a __p.
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* @param __p A pointer that is convertible to element_type*.
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* @post use_count() == 1 && get() == __p
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* @throw std::bad_alloc, in which case @c delete @a __p is called.
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*/
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template<typename _Tp1>
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explicit shared_ptr(_Tp1* __p)
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: __shared_ptr<_Tp>(__p) { }
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/**
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* @brief Construct a %shared_ptr that owns the pointer @a __p
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* and the deleter @a __d.
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* @param __p A pointer.
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* @param __d A deleter.
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* @post use_count() == 1 && get() == __p
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* @throw std::bad_alloc, in which case @a __d(__p) is called.
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*
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* Requirements: _Deleter's copy constructor and destructor must
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* not throw
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*
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* __shared_ptr will release __p by calling __d(__p)
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*/
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template<typename _Tp1, typename _Deleter>
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shared_ptr(_Tp1* __p, _Deleter __d)
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: __shared_ptr<_Tp>(__p, __d) { }
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/**
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* @brief Construct a %shared_ptr that owns a null pointer
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* and the deleter @a __d.
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* @param __p A null pointer constant.
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* @param __d A deleter.
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* @post use_count() == 1 && get() == __p
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* @throw std::bad_alloc, in which case @a __d(__p) is called.
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*
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* Requirements: _Deleter's copy constructor and destructor must
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* not throw
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*
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* The last owner will call __d(__p)
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*/
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template<typename _Deleter>
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shared_ptr(nullptr_t __p, _Deleter __d)
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: __shared_ptr<_Tp>(__p, __d) { }
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/**
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* @brief Construct a %shared_ptr that owns the pointer @a __p
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* and the deleter @a __d.
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* @param __p A pointer.
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* @param __d A deleter.
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* @param __a An allocator.
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* @post use_count() == 1 && get() == __p
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* @throw std::bad_alloc, in which case @a __d(__p) is called.
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*
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* Requirements: _Deleter's copy constructor and destructor must
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* not throw _Alloc's copy constructor and destructor must not
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* throw.
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*
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* __shared_ptr will release __p by calling __d(__p)
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*/
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template<typename _Tp1, typename _Deleter, typename _Alloc>
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shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a)
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: __shared_ptr<_Tp>(__p, __d, std::move(__a)) { }
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/**
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* @brief Construct a %shared_ptr that owns a null pointer
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* and the deleter @a __d.
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* @param __p A null pointer constant.
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* @param __d A deleter.
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* @param __a An allocator.
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* @post use_count() == 1 && get() == __p
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* @throw std::bad_alloc, in which case @a __d(__p) is called.
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*
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* Requirements: _Deleter's copy constructor and destructor must
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* not throw _Alloc's copy constructor and destructor must not
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* throw.
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*
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* The last owner will call __d(__p)
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*/
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template<typename _Deleter, typename _Alloc>
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shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
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: __shared_ptr<_Tp>(__p, __d, std::move(__a)) { }
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// Aliasing constructor
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/**
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* @brief Constructs a %shared_ptr instance that stores @a __p
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* and shares ownership with @a __r.
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* @param __r A %shared_ptr.
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* @param __p A pointer that will remain valid while @a *__r is valid.
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* @post get() == __p && use_count() == __r.use_count()
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*
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* This can be used to construct a @c shared_ptr to a sub-object
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* of an object managed by an existing @c shared_ptr.
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*
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* @code
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* shared_ptr< pair<int,int> > pii(new pair<int,int>());
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* shared_ptr<int> pi(pii, &pii->first);
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* assert(pii.use_count() == 2);
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* @endcode
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*/
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template<typename _Tp1>
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shared_ptr(const shared_ptr<_Tp1>& __r, _Tp* __p)
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: __shared_ptr<_Tp>(__r, __p) { }
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/**
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* @brief If @a __r is empty, constructs an empty %shared_ptr;
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* otherwise construct a %shared_ptr that shares ownership
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* with @a __r.
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* @param __r A %shared_ptr.
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* @post get() == __r.get() && use_count() == __r.use_count()
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*/
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template<typename _Tp1, typename = typename
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std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>
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shared_ptr(const shared_ptr<_Tp1>& __r)
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: __shared_ptr<_Tp>(__r) { }
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/**
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* @brief Move-constructs a %shared_ptr instance from @a __r.
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* @param __r A %shared_ptr rvalue.
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* @post *this contains the old value of @a __r, @a __r is empty.
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*/
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shared_ptr(shared_ptr&& __r)
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: __shared_ptr<_Tp>(std::move(__r)) { }
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/**
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* @brief Move-constructs a %shared_ptr instance from @a __r.
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* @param __r A %shared_ptr rvalue.
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* @post *this contains the old value of @a __r, @a __r is empty.
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*/
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template<typename _Tp1, typename = typename
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std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>
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shared_ptr(shared_ptr<_Tp1>&& __r)
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: __shared_ptr<_Tp>(std::move(__r)) { }
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/**
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* @brief Constructs a %shared_ptr that shares ownership with @a __r
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* and stores a copy of the pointer stored in @a __r.
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* @param __r A weak_ptr.
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* @post use_count() == __r.use_count()
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* @throw bad_weak_ptr when __r.expired(),
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* in which case the constructor has no effect.
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*/
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template<typename _Tp1>
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explicit shared_ptr(const weak_ptr<_Tp1>& __r)
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: __shared_ptr<_Tp>(__r) { }
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#if _GLIBCXX_USE_DEPRECATED
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template<typename _Tp1>
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shared_ptr(std::auto_ptr<_Tp1>&& __r)
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: __shared_ptr<_Tp>(std::move(__r)) { }
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#endif
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template<typename _Tp1, typename _Del>
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shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r)
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: __shared_ptr<_Tp>(std::move(__r)) { }
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/**
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* @brief Construct an empty %shared_ptr.
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* @param __p A null pointer constant.
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* @post use_count() == 0 && get() == nullptr
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*/
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constexpr shared_ptr(nullptr_t __p)
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: __shared_ptr<_Tp>(__p) { }
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template<typename _Tp1>
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shared_ptr&
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operator=(const shared_ptr<_Tp1>& __r) // never throws
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{
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this->__shared_ptr<_Tp>::operator=(__r);
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return *this;
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}
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#if _GLIBCXX_USE_DEPRECATED
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template<typename _Tp1>
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shared_ptr&
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operator=(std::auto_ptr<_Tp1>&& __r)
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{
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this->__shared_ptr<_Tp>::operator=(std::move(__r));
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return *this;
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}
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#endif
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shared_ptr&
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operator=(shared_ptr&& __r)
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{
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this->__shared_ptr<_Tp>::operator=(std::move(__r));
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return *this;
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}
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template<class _Tp1>
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shared_ptr&
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operator=(shared_ptr<_Tp1>&& __r)
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{
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this->__shared_ptr<_Tp>::operator=(std::move(__r));
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return *this;
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}
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template<typename _Tp1, typename _Del>
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shared_ptr&
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operator=(std::unique_ptr<_Tp1, _Del>&& __r)
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{
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this->__shared_ptr<_Tp>::operator=(std::move(__r));
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return *this;
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}
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private:
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// This constructor is non-standard, it is used by allocate_shared.
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template<typename _Alloc, typename... _Args>
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shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a,
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_Args&&... __args)
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: __shared_ptr<_Tp>(__tag, __a, std::forward<_Args>(__args)...)
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{ }
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template<typename _Tp1, typename _Alloc, typename... _Args>
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friend shared_ptr<_Tp1>
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allocate_shared(const _Alloc& __a, _Args&&... __args);
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};
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// 20.8.13.2.7 shared_ptr comparisons
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template<typename _Tp1, typename _Tp2>
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inline bool
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operator==(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b)
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{ return __a.get() == __b.get(); }
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template<typename _Tp>
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inline bool
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operator==(const shared_ptr<_Tp>& __a, nullptr_t)
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{ return __a.get() == nullptr; }
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template<typename _Tp>
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inline bool
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operator==(nullptr_t, const shared_ptr<_Tp>& __b)
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{ return nullptr == __b.get(); }
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template<typename _Tp1, typename _Tp2>
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inline bool
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operator!=(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b)
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{ return __a.get() != __b.get(); }
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template<typename _Tp>
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inline bool
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operator!=(const shared_ptr<_Tp>& __a, nullptr_t)
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{ return __a.get() != nullptr; }
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template<typename _Tp>
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inline bool
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operator!=(nullptr_t, const shared_ptr<_Tp>& __b)
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{ return nullptr != __b.get(); }
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template<typename _Tp1, typename _Tp2>
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inline bool
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operator<(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b)
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{ return __a.get() < __b.get(); }
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template<typename _Tp>
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struct less<shared_ptr<_Tp>> : public _Sp_less<shared_ptr<_Tp>>
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{ };
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// 20.8.13.2.9 shared_ptr specialized algorithms.
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template<typename _Tp>
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inline void
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swap(shared_ptr<_Tp>& __a, shared_ptr<_Tp>& __b)
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{ __a.swap(__b); }
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// 20.8.13.2.10 shared_ptr casts.
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template<typename _Tp, typename _Tp1>
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inline shared_ptr<_Tp>
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static_pointer_cast(const shared_ptr<_Tp1>& __r)
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{ return shared_ptr<_Tp>(__r, static_cast<_Tp*>(__r.get())); }
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template<typename _Tp, typename _Tp1>
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inline shared_ptr<_Tp>
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const_pointer_cast(const shared_ptr<_Tp1>& __r)
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{ return shared_ptr<_Tp>(__r, const_cast<_Tp*>(__r.get())); }
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template<typename _Tp, typename _Tp1>
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inline shared_ptr<_Tp>
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dynamic_pointer_cast(const shared_ptr<_Tp1>& __r)
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{
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if (_Tp* __p = dynamic_cast<_Tp*>(__r.get()))
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return shared_ptr<_Tp>(__r, __p);
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return shared_ptr<_Tp>();
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}
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/**
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* @brief A smart pointer with weak semantics.
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*
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* With forwarding constructors and assignment operators.
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*/
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template<typename _Tp>
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class weak_ptr : public __weak_ptr<_Tp>
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{
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public:
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constexpr weak_ptr()
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: __weak_ptr<_Tp>() { }
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template<typename _Tp1, typename = typename
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std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>
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weak_ptr(const weak_ptr<_Tp1>& __r)
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: __weak_ptr<_Tp>(__r) { }
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template<typename _Tp1, typename = typename
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std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>
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weak_ptr(const shared_ptr<_Tp1>& __r)
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: __weak_ptr<_Tp>(__r) { }
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template<typename _Tp1>
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weak_ptr&
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operator=(const weak_ptr<_Tp1>& __r) // never throws
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{
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this->__weak_ptr<_Tp>::operator=(__r);
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return *this;
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}
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template<typename _Tp1>
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weak_ptr&
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operator=(const shared_ptr<_Tp1>& __r) // never throws
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{
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this->__weak_ptr<_Tp>::operator=(__r);
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return *this;
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}
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shared_ptr<_Tp>
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lock() const // never throws
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{
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#ifdef __GTHREADS
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if (this->expired())
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return shared_ptr<_Tp>();
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__try
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{
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return shared_ptr<_Tp>(*this);
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}
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__catch(const bad_weak_ptr&)
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{
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return shared_ptr<_Tp>();
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}
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#else
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return this->expired() ? shared_ptr<_Tp>() : shared_ptr<_Tp>(*this);
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#endif
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}
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};
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// 20.8.13.3.7 weak_ptr specialized algorithms.
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template<typename _Tp>
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inline void
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swap(weak_ptr<_Tp>& __a, weak_ptr<_Tp>& __b)
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{ __a.swap(__b); }
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/// Primary template owner_less
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template<typename _Tp>
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struct owner_less;
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/// Partial specialization of owner_less for shared_ptr.
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template<typename _Tp>
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struct owner_less<shared_ptr<_Tp>>
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: public _Sp_owner_less<shared_ptr<_Tp>, weak_ptr<_Tp>>
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{ };
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/// Partial specialization of owner_less for weak_ptr.
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template<typename _Tp>
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struct owner_less<weak_ptr<_Tp>>
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: public _Sp_owner_less<weak_ptr<_Tp>, shared_ptr<_Tp>>
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{ };
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/**
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* @brief Base class allowing use of member function shared_from_this.
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*/
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template<typename _Tp>
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class enable_shared_from_this
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{
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protected:
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constexpr enable_shared_from_this() { }
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enable_shared_from_this(const enable_shared_from_this&) { }
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enable_shared_from_this&
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operator=(const enable_shared_from_this&)
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{ return *this; }
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~enable_shared_from_this() { }
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public:
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shared_ptr<_Tp>
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shared_from_this()
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{ return shared_ptr<_Tp>(this->_M_weak_this); }
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shared_ptr<const _Tp>
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shared_from_this() const
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{ return shared_ptr<const _Tp>(this->_M_weak_this); }
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private:
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template<typename _Tp1>
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void
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_M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const
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{ _M_weak_this._M_assign(__p, __n); }
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template<typename _Tp1>
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friend void
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__enable_shared_from_this_helper(const __shared_count<>& __pn,
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const enable_shared_from_this* __pe,
|
|
const _Tp1* __px)
|
|
{
|
|
if (__pe != 0)
|
|
__pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn);
|
|
}
|
|
|
|
mutable weak_ptr<_Tp> _M_weak_this;
|
|
};
|
|
|
|
/**
|
|
* @brief Create an object that is owned by a shared_ptr.
|
|
* @param __a An allocator.
|
|
* @param __args Arguments for the @a _Tp object's constructor.
|
|
* @return A shared_ptr that owns the newly created object.
|
|
* @throw An exception thrown from @a _Alloc::allocate or from the
|
|
* constructor of @a _Tp.
|
|
*
|
|
* A copy of @a __a will be used to allocate memory for the shared_ptr
|
|
* and the new object.
|
|
*/
|
|
template<typename _Tp, typename _Alloc, typename... _Args>
|
|
inline shared_ptr<_Tp>
|
|
allocate_shared(const _Alloc& __a, _Args&&... __args)
|
|
{
|
|
return shared_ptr<_Tp>(_Sp_make_shared_tag(), __a,
|
|
std::forward<_Args>(__args)...);
|
|
}
|
|
|
|
/**
|
|
* @brief Create an object that is owned by a shared_ptr.
|
|
* @param __args Arguments for the @a _Tp object's constructor.
|
|
* @return A shared_ptr that owns the newly created object.
|
|
* @throw std::bad_alloc, or an exception thrown from the
|
|
* constructor of @a _Tp.
|
|
*/
|
|
template<typename _Tp, typename... _Args>
|
|
inline shared_ptr<_Tp>
|
|
make_shared(_Args&&... __args)
|
|
{
|
|
typedef typename std::remove_const<_Tp>::type _Tp_nc;
|
|
return allocate_shared<_Tp>(std::allocator<_Tp_nc>(),
|
|
std::forward<_Args>(__args)...);
|
|
}
|
|
|
|
/// std::hash specialization for shared_ptr.
|
|
template<typename _Tp>
|
|
struct hash<shared_ptr<_Tp>>
|
|
: public std::unary_function<shared_ptr<_Tp>, size_t>
|
|
{
|
|
size_t
|
|
operator()(const shared_ptr<_Tp>& __s) const
|
|
{ return std::hash<_Tp*>()(__s.get()); }
|
|
};
|
|
|
|
// @} group pointer_abstractions
|
|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace
|
|
|
|
#endif // _SHARED_PTR_H
|