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326 lines
7.4 KiB
326 lines
7.4 KiB
#ifndef BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED
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#define BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED
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//
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// weak_ptr.hpp
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//
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// Copyright (c) 2001, 2002, 2003 Peter Dimov
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//
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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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//
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// See http://www.boost.org/libs/smart_ptr/ for documentation.
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//
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#include <boost/smart_ptr/detail/shared_count.hpp>
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#include <boost/smart_ptr/shared_ptr.hpp>
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#include <boost/smart_ptr/detail/sp_noexcept.hpp>
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#include <memory>
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#include <cstddef>
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namespace boost
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{
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template<class T> class weak_ptr
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{
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private:
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// Borland 5.5.1 specific workarounds
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typedef weak_ptr<T> this_type;
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public:
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typedef typename boost::detail::sp_element< T >::type element_type;
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BOOST_CONSTEXPR weak_ptr() BOOST_SP_NOEXCEPT : px(0), pn()
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{
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}
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// generated copy constructor, assignment, destructor are fine...
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#if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES )
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// ... except in C++0x, move disables the implicit copy
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weak_ptr( weak_ptr const & r ) BOOST_SP_NOEXCEPT : px( r.px ), pn( r.pn )
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{
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}
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weak_ptr & operator=( weak_ptr const & r ) BOOST_SP_NOEXCEPT
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{
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px = r.px;
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pn = r.pn;
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return *this;
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}
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#endif
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//
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// The "obvious" converting constructor implementation:
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//
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// template<class Y>
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// weak_ptr(weak_ptr<Y> const & r): px(r.px), pn(r.pn)
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// {
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// }
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//
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// has a serious problem.
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//
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// r.px may already have been invalidated. The px(r.px)
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// conversion may require access to *r.px (virtual inheritance).
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//
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// It is not possible to avoid spurious access violations since
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// in multithreaded programs r.px may be invalidated at any point.
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//
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template<class Y>
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#if !defined( BOOST_SP_NO_SP_CONVERTIBLE )
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weak_ptr( weak_ptr<Y> const & r, typename boost::detail::sp_enable_if_convertible<Y,T>::type = boost::detail::sp_empty() )
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#else
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weak_ptr( weak_ptr<Y> const & r )
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#endif
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BOOST_SP_NOEXCEPT : px(r.lock().get()), pn(r.pn)
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{
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boost::detail::sp_assert_convertible< Y, T >();
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}
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#if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES )
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template<class Y>
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#if !defined( BOOST_SP_NO_SP_CONVERTIBLE )
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weak_ptr( weak_ptr<Y> && r, typename boost::detail::sp_enable_if_convertible<Y,T>::type = boost::detail::sp_empty() )
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#else
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weak_ptr( weak_ptr<Y> && r )
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#endif
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BOOST_SP_NOEXCEPT : px( r.lock().get() ), pn( static_cast< boost::detail::weak_count && >( r.pn ) )
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{
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boost::detail::sp_assert_convertible< Y, T >();
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r.px = 0;
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}
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// for better efficiency in the T == Y case
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weak_ptr( weak_ptr && r )
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BOOST_SP_NOEXCEPT : px( r.px ), pn( static_cast< boost::detail::weak_count && >( r.pn ) )
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{
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r.px = 0;
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}
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// for better efficiency in the T == Y case
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weak_ptr & operator=( weak_ptr && r ) BOOST_SP_NOEXCEPT
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{
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this_type( static_cast< weak_ptr && >( r ) ).swap( *this );
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return *this;
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}
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#endif
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template<class Y>
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#if !defined( BOOST_SP_NO_SP_CONVERTIBLE )
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weak_ptr( shared_ptr<Y> const & r, typename boost::detail::sp_enable_if_convertible<Y,T>::type = boost::detail::sp_empty() )
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#else
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weak_ptr( shared_ptr<Y> const & r )
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#endif
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BOOST_SP_NOEXCEPT : px( r.px ), pn( r.pn )
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{
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boost::detail::sp_assert_convertible< Y, T >();
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}
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// aliasing
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template<class Y> weak_ptr(shared_ptr<Y> const & r, element_type * p) BOOST_SP_NOEXCEPT: px( p ), pn( r.pn )
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{
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}
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template<class Y> weak_ptr(weak_ptr<Y> const & r, element_type * p) BOOST_SP_NOEXCEPT: px( p ), pn( r.pn )
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{
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}
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#if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES )
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template<class Y> weak_ptr(weak_ptr<Y> && r, element_type * p) BOOST_SP_NOEXCEPT: px( p ), pn( std::move( r.pn ) )
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{
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}
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#endif
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#if !defined(BOOST_MSVC) || (BOOST_MSVC >= 1300)
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template<class Y>
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weak_ptr & operator=( weak_ptr<Y> const & r ) BOOST_SP_NOEXCEPT
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{
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boost::detail::sp_assert_convertible< Y, T >();
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px = r.lock().get();
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pn = r.pn;
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return *this;
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}
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#if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES )
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template<class Y>
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weak_ptr & operator=( weak_ptr<Y> && r ) BOOST_SP_NOEXCEPT
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{
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this_type( static_cast< weak_ptr<Y> && >( r ) ).swap( *this );
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return *this;
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}
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#endif
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template<class Y>
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weak_ptr & operator=( shared_ptr<Y> const & r ) BOOST_SP_NOEXCEPT
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{
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boost::detail::sp_assert_convertible< Y, T >();
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px = r.px;
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pn = r.pn;
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return *this;
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}
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#endif
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shared_ptr<T> lock() const BOOST_SP_NOEXCEPT
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{
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return shared_ptr<T>( *this, boost::detail::sp_nothrow_tag() );
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}
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long use_count() const BOOST_SP_NOEXCEPT
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{
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return pn.use_count();
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}
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bool expired() const BOOST_SP_NOEXCEPT
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{
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return pn.use_count() == 0;
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}
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bool _empty() const BOOST_SP_NOEXCEPT // extension, not in std::weak_ptr
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{
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return pn.empty();
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}
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bool empty() const BOOST_SP_NOEXCEPT // extension, not in std::weak_ptr
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{
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return pn.empty();
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}
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void reset() BOOST_SP_NOEXCEPT
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{
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this_type().swap(*this);
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}
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void swap(this_type & other) BOOST_SP_NOEXCEPT
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{
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std::swap(px, other.px);
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pn.swap(other.pn);
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}
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template<class Y> bool owner_before( weak_ptr<Y> const & rhs ) const BOOST_SP_NOEXCEPT
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{
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return pn < rhs.pn;
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}
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template<class Y> bool owner_before( shared_ptr<Y> const & rhs ) const BOOST_SP_NOEXCEPT
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{
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return pn < rhs.pn;
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}
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template<class Y> bool owner_equals( weak_ptr<Y> const & rhs ) const BOOST_SP_NOEXCEPT
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{
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return pn == rhs.pn;
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}
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template<class Y> bool owner_equals( shared_ptr<Y> const & rhs ) const BOOST_SP_NOEXCEPT
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{
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return pn == rhs.pn;
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}
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std::size_t owner_hash_value() const BOOST_SP_NOEXCEPT
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{
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return pn.hash_value();
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}
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// Tasteless as this may seem, making all members public allows member templates
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// to work in the absence of member template friends. (Matthew Langston)
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#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
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private:
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template<class Y> friend class weak_ptr;
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template<class Y> friend class shared_ptr;
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#endif
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element_type * px; // contained pointer
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boost::detail::weak_count pn; // reference counter
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}; // weak_ptr
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template<class T, class U> inline bool operator<(weak_ptr<T> const & a, weak_ptr<U> const & b) BOOST_SP_NOEXCEPT
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{
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return a.owner_before( b );
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}
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template<class T> void swap(weak_ptr<T> & a, weak_ptr<T> & b) BOOST_SP_NOEXCEPT
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{
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a.swap(b);
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}
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#if defined(__cpp_deduction_guides)
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template<class T> weak_ptr( shared_ptr<T> ) -> weak_ptr<T>;
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#endif
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// hash_value
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template< class T > std::size_t hash_value( boost::weak_ptr<T> const & p ) BOOST_SP_NOEXCEPT
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{
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return p.owner_hash_value();
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}
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} // namespace boost
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// std::hash, std::equal_to
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namespace std
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{
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#if !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)
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template<class T> struct hash< ::boost::weak_ptr<T> >
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{
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std::size_t operator()( ::boost::weak_ptr<T> const & p ) const BOOST_SP_NOEXCEPT
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{
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return p.owner_hash_value();
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}
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};
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#endif // #if !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)
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template<class T> struct equal_to< ::boost::weak_ptr<T> >
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{
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bool operator()( ::boost::weak_ptr<T> const & a, ::boost::weak_ptr<T> const & b ) const BOOST_SP_NOEXCEPT
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{
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return a.owner_equals( b );
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}
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};
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} // namespace std
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#endif // #ifndef BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED
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