1 // shared_ptr and weak_ptr implementation details -*- C++ -*-
3 // Copyright (C) 2007-2016 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
25 // GCC Note: Based on files from version 1.32.0 of the Boost library.
28 // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
31 // Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.
32 // Copyright (C) 2001, 2002, 2003 Peter Dimov
35 // Copyright (C) 2001, 2002, 2003 Peter Dimov
37 // enable_shared_from_this.hpp
38 // Copyright (C) 2002 Peter Dimov
40 // Distributed under the Boost Software License, Version 1.0. (See
41 // accompanying file LICENSE_1_0.txt or copy at
42 // http://www.boost.org/LICENSE_1_0.txt)
44 /** @file bits/shared_ptr_base.h
45 * This is an internal header file, included by other library headers.
46 * Do not attempt to use it directly. @headername{memory}
49 #ifndef _SHARED_PTR_BASE_H
50 #define _SHARED_PTR_BASE_H 1
53 #include <bits/allocated_ptr.h>
54 #include <ext/aligned_buffer.h>
56 namespace std
_GLIBCXX_VISIBILITY(default)
58 _GLIBCXX_BEGIN_NAMESPACE_VERSION
60 #if _GLIBCXX_USE_DEPRECATED
61 template<typename
> class auto_ptr
;
65 * @brief Exception possibly thrown by @c shared_ptr.
68 class bad_weak_ptr
: public std::exception
71 virtual char const* what() const noexcept
;
73 virtual ~bad_weak_ptr() noexcept
;
76 // Substitute for bad_weak_ptr object in the case of -fno-exceptions.
78 __throw_bad_weak_ptr()
79 { _GLIBCXX_THROW_OR_ABORT(bad_weak_ptr()); }
81 using __gnu_cxx::_Lock_policy
;
82 using __gnu_cxx::__default_lock_policy
;
83 using __gnu_cxx::_S_single
;
84 using __gnu_cxx::_S_mutex
;
85 using __gnu_cxx::_S_atomic
;
87 // Empty helper class except when the template argument is _S_mutex.
88 template<_Lock_policy _Lp
>
92 // The atomic policy uses fully-fenced builtins, single doesn't care.
93 enum { _S_need_barriers
= 0 };
97 class _Mutex_base
<_S_mutex
>
98 : public __gnu_cxx::__mutex
101 // This policy is used when atomic builtins are not available.
102 // The replacement atomic operations might not have the necessary
104 enum { _S_need_barriers
= 1 };
107 template<_Lock_policy _Lp
= __default_lock_policy
>
108 class _Sp_counted_base
109 : public _Mutex_base
<_Lp
>
112 _Sp_counted_base() noexcept
113 : _M_use_count(1), _M_weak_count(1) { }
116 ~_Sp_counted_base() noexcept
119 // Called when _M_use_count drops to zero, to release the resources
122 _M_dispose() noexcept
= 0;
124 // Called when _M_weak_count drops to zero.
126 _M_destroy() noexcept
130 _M_get_deleter(const std::type_info
&) noexcept
= 0;
134 { __gnu_cxx::__atomic_add_dispatch(&_M_use_count
, 1); }
140 _M_add_ref_lock_nothrow();
143 _M_release() noexcept
145 // Be race-detector-friendly. For more info see bits/c++config.
146 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count
);
147 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count
, -1) == 1)
149 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count
);
151 // There must be a memory barrier between dispose() and destroy()
152 // to ensure that the effects of dispose() are observed in the
153 // thread that runs destroy().
154 // See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html
155 if (_Mutex_base
<_Lp
>::_S_need_barriers
)
157 __atomic_thread_fence (__ATOMIC_ACQ_REL
);
160 // Be race-detector-friendly. For more info see bits/c++config.
161 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count
);
162 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count
,
165 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count
);
172 _M_weak_add_ref() noexcept
173 { __gnu_cxx::__atomic_add_dispatch(&_M_weak_count
, 1); }
176 _M_weak_release() noexcept
178 // Be race-detector-friendly. For more info see bits/c++config.
179 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count
);
180 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count
, -1) == 1)
182 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count
);
183 if (_Mutex_base
<_Lp
>::_S_need_barriers
)
186 // destroy() must observe results of dispose()
187 __atomic_thread_fence (__ATOMIC_ACQ_REL
);
194 _M_get_use_count() const noexcept
196 // No memory barrier is used here so there is no synchronization
197 // with other threads.
198 return __atomic_load_n(&_M_use_count
, __ATOMIC_RELAXED
);
202 _Sp_counted_base(_Sp_counted_base
const&) = delete;
203 _Sp_counted_base
& operator=(_Sp_counted_base
const&) = delete;
205 _Atomic_word _M_use_count
; // #shared
206 _Atomic_word _M_weak_count
; // #weak + (#shared != 0)
211 _Sp_counted_base
<_S_single
>::
214 if (_M_use_count
== 0)
215 __throw_bad_weak_ptr();
221 _Sp_counted_base
<_S_mutex
>::
224 __gnu_cxx::__scoped_lock
sentry(*this);
225 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count
, 1) == 0)
228 __throw_bad_weak_ptr();
234 _Sp_counted_base
<_S_atomic
>::
237 // Perform lock-free add-if-not-zero operation.
238 _Atomic_word __count
= _M_get_use_count();
242 __throw_bad_weak_ptr();
243 // Replace the current counter value with the old value + 1, as
244 // long as it's not changed meanwhile.
246 while (!__atomic_compare_exchange_n(&_M_use_count
, &__count
, __count
+ 1,
247 true, __ATOMIC_ACQ_REL
,
253 _Sp_counted_base
<_S_single
>::
254 _M_add_ref_lock_nothrow()
256 if (_M_use_count
== 0)
264 _Sp_counted_base
<_S_mutex
>::
265 _M_add_ref_lock_nothrow()
267 __gnu_cxx::__scoped_lock
sentry(*this);
268 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count
, 1) == 0)
278 _Sp_counted_base
<_S_atomic
>::
279 _M_add_ref_lock_nothrow()
281 // Perform lock-free add-if-not-zero operation.
282 _Atomic_word __count
= _M_get_use_count();
287 // Replace the current counter value with the old value + 1, as
288 // long as it's not changed meanwhile.
290 while (!__atomic_compare_exchange_n(&_M_use_count
, &__count
, __count
+ 1,
291 true, __ATOMIC_ACQ_REL
,
298 _Sp_counted_base
<_S_single
>::_M_add_ref_copy()
303 _Sp_counted_base
<_S_single
>::_M_release() noexcept
305 if (--_M_use_count
== 0)
308 if (--_M_weak_count
== 0)
315 _Sp_counted_base
<_S_single
>::_M_weak_add_ref() noexcept
320 _Sp_counted_base
<_S_single
>::_M_weak_release() noexcept
322 if (--_M_weak_count
== 0)
328 _Sp_counted_base
<_S_single
>::_M_get_use_count() const noexcept
329 { return _M_use_count
; }
332 // Forward declarations.
333 template<typename _Tp
, _Lock_policy _Lp
= __default_lock_policy
>
336 template<typename _Tp
, _Lock_policy _Lp
= __default_lock_policy
>
339 template<typename _Tp
, _Lock_policy _Lp
= __default_lock_policy
>
340 class __enable_shared_from_this
;
342 template<typename _Tp
>
345 template<typename _Tp
>
348 template<typename _Tp
>
351 template<typename _Tp
>
352 class enable_shared_from_this
;
354 template<_Lock_policy _Lp
= __default_lock_policy
>
357 template<_Lock_policy _Lp
= __default_lock_policy
>
358 class __shared_count
;
361 // Counted ptr with no deleter or allocator support
362 template<typename _Ptr
, _Lock_policy _Lp
>
363 class _Sp_counted_ptr final
: public _Sp_counted_base
<_Lp
>
367 _Sp_counted_ptr(_Ptr __p
) noexcept
371 _M_dispose() noexcept
375 _M_destroy() noexcept
379 _M_get_deleter(const std::type_info
&) noexcept
382 _Sp_counted_ptr(const _Sp_counted_ptr
&) = delete;
383 _Sp_counted_ptr
& operator=(const _Sp_counted_ptr
&) = delete;
391 _Sp_counted_ptr
<nullptr_t
, _S_single
>::_M_dispose() noexcept
{ }
395 _Sp_counted_ptr
<nullptr_t
, _S_mutex
>::_M_dispose() noexcept
{ }
399 _Sp_counted_ptr
<nullptr_t
, _S_atomic
>::_M_dispose() noexcept
{ }
401 template<int _Nm
, typename _Tp
,
402 bool __use_ebo
= !__is_final(_Tp
) && __is_empty(_Tp
)>
403 struct _Sp_ebo_helper
;
405 /// Specialization using EBO.
406 template<int _Nm
, typename _Tp
>
407 struct _Sp_ebo_helper
<_Nm
, _Tp
, true> : private _Tp
409 explicit _Sp_ebo_helper(const _Tp
& __tp
) : _Tp(__tp
) { }
412 _S_get(_Sp_ebo_helper
& __eboh
) { return static_cast<_Tp
&>(__eboh
); }
415 /// Specialization not using EBO.
416 template<int _Nm
, typename _Tp
>
417 struct _Sp_ebo_helper
<_Nm
, _Tp
, false>
419 explicit _Sp_ebo_helper(const _Tp
& __tp
) : _M_tp(__tp
) { }
422 _S_get(_Sp_ebo_helper
& __eboh
)
423 { return __eboh
._M_tp
; }
429 // Support for custom deleter and/or allocator
430 template<typename _Ptr
, typename _Deleter
, typename _Alloc
, _Lock_policy _Lp
>
431 class _Sp_counted_deleter final
: public _Sp_counted_base
<_Lp
>
433 class _Impl
: _Sp_ebo_helper
<0, _Deleter
>, _Sp_ebo_helper
<1, _Alloc
>
435 typedef _Sp_ebo_helper
<0, _Deleter
> _Del_base
;
436 typedef _Sp_ebo_helper
<1, _Alloc
> _Alloc_base
;
439 _GLIBCXX_ABI_TAG_EMPTY
440 _Impl(_Ptr __p
, _Deleter __d
, const _Alloc
& __a
) noexcept
441 : _M_ptr(__p
), _Del_base(__d
), _Alloc_base(__a
)
444 _Deleter
& _M_del() noexcept
{ return _Del_base::_S_get(*this); }
445 _Alloc
& _M_alloc() noexcept
{ return _Alloc_base::_S_get(*this); }
451 using __allocator_type
= __alloc_rebind
<_Alloc
, _Sp_counted_deleter
>;
453 // __d(__p) must not throw.
454 _Sp_counted_deleter(_Ptr __p
, _Deleter __d
) noexcept
455 : _M_impl(__p
, __d
, _Alloc()) { }
457 // __d(__p) must not throw.
458 _GLIBCXX_ABI_TAG_EMPTY
459 _Sp_counted_deleter(_Ptr __p
, _Deleter __d
, const _Alloc
& __a
) noexcept
460 : _M_impl(__p
, __d
, __a
) { }
462 ~_Sp_counted_deleter() noexcept
{ }
465 _M_dispose() noexcept
466 { _M_impl
._M_del()(_M_impl
._M_ptr
); }
469 _M_destroy() noexcept
471 __allocator_type
__a(_M_impl
._M_alloc());
472 __allocated_ptr
<__allocator_type
> __guard_ptr
{ __a
, this };
473 this->~_Sp_counted_deleter();
477 _M_get_deleter(const std::type_info
& __ti
) noexcept
480 // _GLIBCXX_RESOLVE_LIB_DEFECTS
481 // 2400. shared_ptr's get_deleter() should use addressof()
482 return __ti
== typeid(_Deleter
)
483 ? std::__addressof(_M_impl
._M_del())
494 // helpers for make_shared / allocate_shared
496 struct _Sp_make_shared_tag
{ };
498 template<typename _Tp
, typename _Alloc
, _Lock_policy _Lp
>
499 class _Sp_counted_ptr_inplace final
: public _Sp_counted_base
<_Lp
>
501 class _Impl
: _Sp_ebo_helper
<0, _Alloc
>
503 typedef _Sp_ebo_helper
<0, _Alloc
> _A_base
;
506 explicit _Impl(_Alloc __a
) noexcept
: _A_base(__a
) { }
508 _Alloc
& _M_alloc() noexcept
{ return _A_base::_S_get(*this); }
510 __gnu_cxx::__aligned_buffer
<_Tp
> _M_storage
;
514 using __allocator_type
= __alloc_rebind
<_Alloc
, _Sp_counted_ptr_inplace
>;
516 template<typename
... _Args
>
517 _Sp_counted_ptr_inplace(_Alloc __a
, _Args
&&... __args
)
520 // _GLIBCXX_RESOLVE_LIB_DEFECTS
521 // 2070. allocate_shared should use allocator_traits<A>::construct
522 allocator_traits
<_Alloc
>::construct(__a
, _M_ptr(),
523 std::forward
<_Args
>(__args
)...); // might throw
526 ~_Sp_counted_ptr_inplace() noexcept
{ }
529 _M_dispose() noexcept
531 allocator_traits
<_Alloc
>::destroy(_M_impl
._M_alloc(), _M_ptr());
534 // Override because the allocator needs to know the dynamic type
536 _M_destroy() noexcept
538 __allocator_type
__a(_M_impl
._M_alloc());
539 __allocated_ptr
<__allocator_type
> __guard_ptr
{ __a
, this };
540 this->~_Sp_counted_ptr_inplace();
543 // Sneaky trick so __shared_ptr can get the managed pointer
545 _M_get_deleter(const std::type_info
& __ti
) noexcept
548 if (__ti
== typeid(_Sp_make_shared_tag
))
549 return const_cast<typename remove_cv
<_Tp
>::type
*>(_M_ptr());
555 _Tp
* _M_ptr() noexcept
{ return _M_impl
._M_storage
._M_ptr(); }
561 template<_Lock_policy _Lp
>
565 constexpr __shared_count() noexcept
: _M_pi(0)
568 template<typename _Ptr
>
570 __shared_count(_Ptr __p
) : _M_pi(0)
574 _M_pi
= new _Sp_counted_ptr
<_Ptr
, _Lp
>(__p
);
579 __throw_exception_again
;
583 template<typename _Ptr
, typename _Deleter
>
584 __shared_count(_Ptr __p
, _Deleter __d
)
585 : __shared_count(__p
, std::move(__d
), allocator
<void>())
588 template<typename _Ptr
, typename _Deleter
, typename _Alloc
>
589 _GLIBCXX_ABI_TAG_EMPTY
590 __shared_count(_Ptr __p
, _Deleter __d
, _Alloc __a
) : _M_pi(0)
592 typedef _Sp_counted_deleter
<_Ptr
, _Deleter
, _Alloc
, _Lp
> _Sp_cd_type
;
595 typename
_Sp_cd_type::__allocator_type
__a2(__a
);
596 auto __guard
= std::__allocate_guarded(__a2
);
597 _Sp_cd_type
* __mem
= __guard
.get();
598 ::new (__mem
) _Sp_cd_type(__p
, std::move(__d
), std::move(__a
));
604 __d(__p
); // Call _Deleter on __p.
605 __throw_exception_again
;
609 template<typename _Tp
, typename _Alloc
, typename
... _Args
>
610 __shared_count(_Sp_make_shared_tag
, _Tp
*, const _Alloc
& __a
,
614 typedef _Sp_counted_ptr_inplace
<_Tp
, _Alloc
, _Lp
> _Sp_cp_type
;
615 typename
_Sp_cp_type::__allocator_type
__a2(__a
);
616 auto __guard
= std::__allocate_guarded(__a2
);
617 _Sp_cp_type
* __mem
= __guard
.get();
618 ::new (__mem
) _Sp_cp_type(std::move(__a
),
619 std::forward
<_Args
>(__args
)...);
624 #if _GLIBCXX_USE_DEPRECATED
625 // Special case for auto_ptr<_Tp> to provide the strong guarantee.
626 template<typename _Tp
>
628 __shared_count(std::auto_ptr
<_Tp
>&& __r
);
631 // Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee.
632 template<typename _Tp
, typename _Del
>
634 __shared_count(std::unique_ptr
<_Tp
, _Del
>&& __r
) : _M_pi(0)
636 // _GLIBCXX_RESOLVE_LIB_DEFECTS
637 // 2415. Inconsistency between unique_ptr and shared_ptr
638 if (__r
.get() == nullptr)
641 using _Ptr
= typename unique_ptr
<_Tp
, _Del
>::pointer
;
642 using _Del2
= typename conditional
<is_reference
<_Del
>::value
,
643 reference_wrapper
<typename remove_reference
<_Del
>::type
>,
646 = _Sp_counted_deleter
<_Ptr
, _Del2
, allocator
<void>, _Lp
>;
647 using _Alloc
= allocator
<_Sp_cd_type
>;
648 using _Alloc_traits
= allocator_traits
<_Alloc
>;
650 _Sp_cd_type
* __mem
= _Alloc_traits::allocate(__a
, 1);
651 _Alloc_traits::construct(__a
, __mem
, __r
.release(),
652 __r
.get_deleter()); // non-throwing
656 // Throw bad_weak_ptr when __r._M_get_use_count() == 0.
657 explicit __shared_count(const __weak_count
<_Lp
>& __r
);
659 // Does not throw if __r._M_get_use_count() == 0, caller must check.
660 explicit __shared_count(const __weak_count
<_Lp
>& __r
, std::nothrow_t
);
662 ~__shared_count() noexcept
664 if (_M_pi
!= nullptr)
668 __shared_count(const __shared_count
& __r
) noexcept
672 _M_pi
->_M_add_ref_copy();
676 operator=(const __shared_count
& __r
) noexcept
678 _Sp_counted_base
<_Lp
>* __tmp
= __r
._M_pi
;
682 __tmp
->_M_add_ref_copy();
691 _M_swap(__shared_count
& __r
) noexcept
693 _Sp_counted_base
<_Lp
>* __tmp
= __r
._M_pi
;
699 _M_get_use_count() const noexcept
700 { return _M_pi
!= 0 ? _M_pi
->_M_get_use_count() : 0; }
703 _M_unique() const noexcept
704 { return this->_M_get_use_count() == 1; }
707 _M_get_deleter(const std::type_info
& __ti
) const noexcept
708 { return _M_pi
? _M_pi
->_M_get_deleter(__ti
) : nullptr; }
711 _M_less(const __shared_count
& __rhs
) const noexcept
712 { return std::less
<_Sp_counted_base
<_Lp
>*>()(this->_M_pi
, __rhs
._M_pi
); }
715 _M_less(const __weak_count
<_Lp
>& __rhs
) const noexcept
716 { return std::less
<_Sp_counted_base
<_Lp
>*>()(this->_M_pi
, __rhs
._M_pi
); }
718 // Friend function injected into enclosing namespace and found by ADL
720 operator==(const __shared_count
& __a
, const __shared_count
& __b
) noexcept
721 { return __a
._M_pi
== __b
._M_pi
; }
724 friend class __weak_count
<_Lp
>;
726 _Sp_counted_base
<_Lp
>* _M_pi
;
730 template<_Lock_policy _Lp
>
734 constexpr __weak_count() noexcept
: _M_pi(nullptr)
737 __weak_count(const __shared_count
<_Lp
>& __r
) noexcept
740 if (_M_pi
!= nullptr)
741 _M_pi
->_M_weak_add_ref();
744 __weak_count(const __weak_count
& __r
) noexcept
747 if (_M_pi
!= nullptr)
748 _M_pi
->_M_weak_add_ref();
751 __weak_count(__weak_count
&& __r
) noexcept
753 { __r
._M_pi
= nullptr; }
755 ~__weak_count() noexcept
757 if (_M_pi
!= nullptr)
758 _M_pi
->_M_weak_release();
762 operator=(const __shared_count
<_Lp
>& __r
) noexcept
764 _Sp_counted_base
<_Lp
>* __tmp
= __r
._M_pi
;
765 if (__tmp
!= nullptr)
766 __tmp
->_M_weak_add_ref();
767 if (_M_pi
!= nullptr)
768 _M_pi
->_M_weak_release();
774 operator=(const __weak_count
& __r
) noexcept
776 _Sp_counted_base
<_Lp
>* __tmp
= __r
._M_pi
;
777 if (__tmp
!= nullptr)
778 __tmp
->_M_weak_add_ref();
779 if (_M_pi
!= nullptr)
780 _M_pi
->_M_weak_release();
786 operator=(__weak_count
&& __r
) noexcept
788 if (_M_pi
!= nullptr)
789 _M_pi
->_M_weak_release();
796 _M_swap(__weak_count
& __r
) noexcept
798 _Sp_counted_base
<_Lp
>* __tmp
= __r
._M_pi
;
804 _M_get_use_count() const noexcept
805 { return _M_pi
!= nullptr ? _M_pi
->_M_get_use_count() : 0; }
808 _M_less(const __weak_count
& __rhs
) const noexcept
809 { return std::less
<_Sp_counted_base
<_Lp
>*>()(this->_M_pi
, __rhs
._M_pi
); }
812 _M_less(const __shared_count
<_Lp
>& __rhs
) const noexcept
813 { return std::less
<_Sp_counted_base
<_Lp
>*>()(this->_M_pi
, __rhs
._M_pi
); }
815 // Friend function injected into enclosing namespace and found by ADL
817 operator==(const __weak_count
& __a
, const __weak_count
& __b
) noexcept
818 { return __a
._M_pi
== __b
._M_pi
; }
821 friend class __shared_count
<_Lp
>;
823 _Sp_counted_base
<_Lp
>* _M_pi
;
826 // Now that __weak_count is defined we can define this constructor:
827 template<_Lock_policy _Lp
>
829 __shared_count
<_Lp
>::__shared_count(const __weak_count
<_Lp
>& __r
)
832 if (_M_pi
!= nullptr)
833 _M_pi
->_M_add_ref_lock();
835 __throw_bad_weak_ptr();
838 // Now that __weak_count is defined we can define this constructor:
839 template<_Lock_policy _Lp
>
841 __shared_count
<_Lp
>::
842 __shared_count(const __weak_count
<_Lp
>& __r
, std::nothrow_t
)
845 if (_M_pi
!= nullptr)
846 if (!_M_pi
->_M_add_ref_lock_nothrow())
850 // Support for enable_shared_from_this.
852 // Friend of __enable_shared_from_this.
853 template<_Lock_policy _Lp
, typename _Tp1
, typename _Tp2
>
855 __enable_shared_from_this_helper(const __shared_count
<_Lp
>&,
856 const __enable_shared_from_this
<_Tp1
,
857 _Lp
>*, const _Tp2
*) noexcept
;
859 // Friend of enable_shared_from_this.
860 template<typename _Tp1
, typename _Tp2
>
862 __enable_shared_from_this_helper(const __shared_count
<>&,
863 const enable_shared_from_this
<_Tp1
>*,
864 const _Tp2
*) noexcept
;
866 template<_Lock_policy _Lp
>
868 __enable_shared_from_this_helper(const __shared_count
<_Lp
>&, ...) noexcept
872 template<typename _Tp
, _Lock_policy _Lp
>
875 template<typename _Ptr
>
877 = typename enable_if
<is_convertible
<_Ptr
, _Tp
*>::value
>::type
;
880 typedef _Tp element_type
;
882 constexpr __shared_ptr() noexcept
883 : _M_ptr(0), _M_refcount()
886 template<typename _Tp1
>
887 explicit __shared_ptr(_Tp1
* __p
)
888 : _M_ptr(__p
), _M_refcount(__p
)
890 __glibcxx_function_requires(_ConvertibleConcept
<_Tp1
*, _Tp
*>)
891 static_assert( !is_void
<_Tp1
>::value
, "incomplete type" );
892 static_assert( sizeof(_Tp1
) > 0, "incomplete type" );
893 __enable_shared_from_this_helper(_M_refcount
, __p
, __p
);
896 template<typename _Tp1
, typename _Deleter
>
897 __shared_ptr(_Tp1
* __p
, _Deleter __d
)
898 : _M_ptr(__p
), _M_refcount(__p
, __d
)
900 __glibcxx_function_requires(_ConvertibleConcept
<_Tp1
*, _Tp
*>)
901 // TODO requires _Deleter CopyConstructible and __d(__p) well-formed
902 __enable_shared_from_this_helper(_M_refcount
, __p
, __p
);
905 template<typename _Tp1
, typename _Deleter
, typename _Alloc
>
906 _GLIBCXX_ABI_TAG_EMPTY
907 __shared_ptr(_Tp1
* __p
, _Deleter __d
, _Alloc __a
)
908 : _M_ptr(__p
), _M_refcount(__p
, __d
, std::move(__a
))
910 __glibcxx_function_requires(_ConvertibleConcept
<_Tp1
*, _Tp
*>)
911 // TODO requires _Deleter CopyConstructible and __d(__p) well-formed
912 __enable_shared_from_this_helper(_M_refcount
, __p
, __p
);
915 template<typename _Deleter
>
916 __shared_ptr(nullptr_t __p
, _Deleter __d
)
917 : _M_ptr(0), _M_refcount(__p
, __d
)
920 template<typename _Deleter
, typename _Alloc
>
921 _GLIBCXX_ABI_TAG_EMPTY
922 __shared_ptr(nullptr_t __p
, _Deleter __d
, _Alloc __a
)
923 : _M_ptr(0), _M_refcount(__p
, __d
, std::move(__a
))
926 template<typename _Tp1
>
927 __shared_ptr(const __shared_ptr
<_Tp1
, _Lp
>& __r
, _Tp
* __p
) noexcept
928 : _M_ptr(__p
), _M_refcount(__r
._M_refcount
) // never throws
931 __shared_ptr(const __shared_ptr
&) noexcept
= default;
932 __shared_ptr
& operator=(const __shared_ptr
&) noexcept
= default;
933 ~__shared_ptr() = default;
935 template<typename _Tp1
, typename
= _Convertible
<_Tp1
*>>
936 __shared_ptr(const __shared_ptr
<_Tp1
, _Lp
>& __r
) noexcept
937 : _M_ptr(__r
._M_ptr
), _M_refcount(__r
._M_refcount
)
940 __shared_ptr(__shared_ptr
&& __r
) noexcept
941 : _M_ptr(__r
._M_ptr
), _M_refcount()
943 _M_refcount
._M_swap(__r
._M_refcount
);
947 template<typename _Tp1
, typename
= _Convertible
<_Tp1
*>>
948 __shared_ptr(__shared_ptr
<_Tp1
, _Lp
>&& __r
) noexcept
949 : _M_ptr(__r
._M_ptr
), _M_refcount()
951 _M_refcount
._M_swap(__r
._M_refcount
);
955 template<typename _Tp1
>
956 explicit __shared_ptr(const __weak_ptr
<_Tp1
, _Lp
>& __r
)
957 : _M_refcount(__r
._M_refcount
) // may throw
959 __glibcxx_function_requires(_ConvertibleConcept
<_Tp1
*, _Tp
*>)
961 // It is now safe to copy __r._M_ptr, as
962 // _M_refcount(__r._M_refcount) did not throw.
966 // If an exception is thrown this constructor has no effect.
967 template<typename _Tp1
, typename _Del
, typename
968 = _Convertible
<typename unique_ptr
<_Tp1
, _Del
>::pointer
>>
969 __shared_ptr(std::unique_ptr
<_Tp1
, _Del
>&& __r
)
970 : _M_ptr(__r
.get()), _M_refcount()
972 __glibcxx_function_requires(_ConvertibleConcept
<_Tp1
*, _Tp
*>)
973 auto __raw
= _S_raw_ptr(__r
.get());
974 _M_refcount
= __shared_count
<_Lp
>(std::move(__r
));
975 __enable_shared_from_this_helper(_M_refcount
, __raw
, __raw
);
978 #if _GLIBCXX_USE_DEPRECATED
979 // Postcondition: use_count() == 1 and __r.get() == 0
980 template<typename _Tp1
>
981 __shared_ptr(std::auto_ptr
<_Tp1
>&& __r
);
984 constexpr __shared_ptr(nullptr_t
) noexcept
: __shared_ptr() { }
986 template<typename _Tp1
>
988 operator=(const __shared_ptr
<_Tp1
, _Lp
>& __r
) noexcept
991 _M_refcount
= __r
._M_refcount
; // __shared_count::op= doesn't throw
995 #if _GLIBCXX_USE_DEPRECATED
996 template<typename _Tp1
>
998 operator=(std::auto_ptr
<_Tp1
>&& __r
)
1000 __shared_ptr(std::move(__r
)).swap(*this);
1006 operator=(__shared_ptr
&& __r
) noexcept
1008 __shared_ptr(std::move(__r
)).swap(*this);
1012 template<class _Tp1
>
1014 operator=(__shared_ptr
<_Tp1
, _Lp
>&& __r
) noexcept
1016 __shared_ptr(std::move(__r
)).swap(*this);
1020 template<typename _Tp1
, typename _Del
>
1022 operator=(std::unique_ptr
<_Tp1
, _Del
>&& __r
)
1024 __shared_ptr(std::move(__r
)).swap(*this);
1030 { __shared_ptr().swap(*this); }
1032 template<typename _Tp1
>
1034 reset(_Tp1
* __p
) // _Tp1 must be complete.
1036 // Catch self-reset errors.
1037 __glibcxx_assert(__p
== 0 || __p
!= _M_ptr
);
1038 __shared_ptr(__p
).swap(*this);
1041 template<typename _Tp1
, typename _Deleter
>
1043 reset(_Tp1
* __p
, _Deleter __d
)
1044 { __shared_ptr(__p
, __d
).swap(*this); }
1046 template<typename _Tp1
, typename _Deleter
, typename _Alloc
>
1047 _GLIBCXX_ABI_TAG_EMPTY
1049 reset(_Tp1
* __p
, _Deleter __d
, _Alloc __a
)
1050 { __shared_ptr(__p
, __d
, std::move(__a
)).swap(*this); }
1052 // Allow class instantiation when _Tp is [cv-qual] void.
1053 typename
std::add_lvalue_reference
<_Tp
>::type
1054 operator*() const noexcept
1056 __glibcxx_assert(_M_ptr
!= 0);
1061 operator->() const noexcept
1063 _GLIBCXX_DEBUG_PEDASSERT(_M_ptr
!= 0);
1068 get() const noexcept
1071 explicit operator bool() const // never throws
1072 { return _M_ptr
== 0 ? false : true; }
1075 unique() const noexcept
1076 { return _M_refcount
._M_unique(); }
1079 use_count() const noexcept
1080 { return _M_refcount
._M_get_use_count(); }
1083 swap(__shared_ptr
<_Tp
, _Lp
>& __other
) noexcept
1085 std::swap(_M_ptr
, __other
._M_ptr
);
1086 _M_refcount
._M_swap(__other
._M_refcount
);
1089 template<typename _Tp1
>
1091 owner_before(__shared_ptr
<_Tp1
, _Lp
> const& __rhs
) const
1092 { return _M_refcount
._M_less(__rhs
._M_refcount
); }
1094 template<typename _Tp1
>
1096 owner_before(__weak_ptr
<_Tp1
, _Lp
> const& __rhs
) const
1097 { return _M_refcount
._M_less(__rhs
._M_refcount
); }
1101 // This constructor is non-standard, it is used by allocate_shared.
1102 template<typename _Alloc
, typename
... _Args
>
1103 __shared_ptr(_Sp_make_shared_tag __tag
, const _Alloc
& __a
,
1105 : _M_ptr(), _M_refcount(__tag
, (_Tp
*)0, __a
,
1106 std::forward
<_Args
>(__args
)...)
1108 // _M_ptr needs to point to the newly constructed object.
1109 // This relies on _Sp_counted_ptr_inplace::_M_get_deleter.
1110 void* __p
= _M_refcount
._M_get_deleter(typeid(__tag
));
1111 _M_ptr
= static_cast<_Tp
*>(__p
);
1112 __enable_shared_from_this_helper(_M_refcount
, _M_ptr
, _M_ptr
);
1115 template<typename _Alloc
>
1118 void operator()(typename
_Alloc::value_type
* __ptr
)
1120 __allocated_ptr
<_Alloc
> __guard
{ _M_alloc
, __ptr
};
1121 allocator_traits
<_Alloc
>::destroy(_M_alloc
, __guard
.get());
1126 template<typename _Alloc
, typename
... _Args
>
1127 __shared_ptr(_Sp_make_shared_tag __tag
, const _Alloc
& __a
,
1129 : _M_ptr(), _M_refcount()
1131 typedef typename allocator_traits
<_Alloc
>::template
1132 rebind_traits
<typename
std::remove_cv
<_Tp
>::type
> __traits
;
1133 _Deleter
<typename
__traits::allocator_type
> __del
= { __a
};
1134 auto __guard
= std::__allocate_guarded(__del
._M_alloc
);
1135 auto __ptr
= __guard
.get();
1136 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1137 // 2070. allocate_shared should use allocator_traits<A>::construct
1138 __traits::construct(__del
._M_alloc
, __ptr
,
1139 std::forward
<_Args
>(__args
)...);
1141 __shared_count
<_Lp
> __count(__ptr
, __del
, __del
._M_alloc
);
1142 _M_refcount
._M_swap(__count
);
1144 __enable_shared_from_this_helper(_M_refcount
, _M_ptr
, _M_ptr
);
1148 template<typename _Tp1
, _Lock_policy _Lp1
, typename _Alloc
,
1150 friend __shared_ptr
<_Tp1
, _Lp1
>
1151 __allocate_shared(const _Alloc
& __a
, _Args
&&... __args
);
1153 // This constructor is used by __weak_ptr::lock() and
1154 // shared_ptr::shared_ptr(const weak_ptr&, std::nothrow_t).
1155 __shared_ptr(const __weak_ptr
<_Tp
, _Lp
>& __r
, std::nothrow_t
)
1156 : _M_refcount(__r
._M_refcount
, std::nothrow
)
1158 _M_ptr
= _M_refcount
._M_get_use_count() ? __r
._M_ptr
: nullptr;
1161 friend class __weak_ptr
<_Tp
, _Lp
>;
1165 _M_get_deleter(const std::type_info
& __ti
) const noexcept
1166 { return _M_refcount
._M_get_deleter(__ti
); }
1168 template<typename _Tp1
>
1170 _S_raw_ptr(_Tp1
* __ptr
)
1173 template<typename _Tp1
>
1175 _S_raw_ptr(_Tp1 __ptr
) -> decltype(std::__addressof(*__ptr
))
1176 { return std::__addressof(*__ptr
); }
1178 template<typename _Tp1
, _Lock_policy _Lp1
> friend class __shared_ptr
;
1179 template<typename _Tp1
, _Lock_policy _Lp1
> friend class __weak_ptr
;
1181 template<typename _Del
, typename _Tp1
, _Lock_policy _Lp1
>
1182 friend _Del
* get_deleter(const __shared_ptr
<_Tp1
, _Lp1
>&) noexcept
;
1184 _Tp
* _M_ptr
; // Contained pointer.
1185 __shared_count
<_Lp
> _M_refcount
; // Reference counter.
1189 // 20.7.2.2.7 shared_ptr comparisons
1190 template<typename _Tp1
, typename _Tp2
, _Lock_policy _Lp
>
1192 operator==(const __shared_ptr
<_Tp1
, _Lp
>& __a
,
1193 const __shared_ptr
<_Tp2
, _Lp
>& __b
) noexcept
1194 { return __a
.get() == __b
.get(); }
1196 template<typename _Tp
, _Lock_policy _Lp
>
1198 operator==(const __shared_ptr
<_Tp
, _Lp
>& __a
, nullptr_t
) noexcept
1201 template<typename _Tp
, _Lock_policy _Lp
>
1203 operator==(nullptr_t
, const __shared_ptr
<_Tp
, _Lp
>& __a
) noexcept
1206 template<typename _Tp1
, typename _Tp2
, _Lock_policy _Lp
>
1208 operator!=(const __shared_ptr
<_Tp1
, _Lp
>& __a
,
1209 const __shared_ptr
<_Tp2
, _Lp
>& __b
) noexcept
1210 { return __a
.get() != __b
.get(); }
1212 template<typename _Tp
, _Lock_policy _Lp
>
1214 operator!=(const __shared_ptr
<_Tp
, _Lp
>& __a
, nullptr_t
) noexcept
1215 { return (bool)__a
; }
1217 template<typename _Tp
, _Lock_policy _Lp
>
1219 operator!=(nullptr_t
, const __shared_ptr
<_Tp
, _Lp
>& __a
) noexcept
1220 { return (bool)__a
; }
1222 template<typename _Tp1
, typename _Tp2
, _Lock_policy _Lp
>
1224 operator<(const __shared_ptr
<_Tp1
, _Lp
>& __a
,
1225 const __shared_ptr
<_Tp2
, _Lp
>& __b
) noexcept
1227 typedef typename
std::common_type
<_Tp1
*, _Tp2
*>::type _CT
;
1228 return std::less
<_CT
>()(__a
.get(), __b
.get());
1231 template<typename _Tp
, _Lock_policy _Lp
>
1233 operator<(const __shared_ptr
<_Tp
, _Lp
>& __a
, nullptr_t
) noexcept
1234 { return std::less
<_Tp
*>()(__a
.get(), nullptr); }
1236 template<typename _Tp
, _Lock_policy _Lp
>
1238 operator<(nullptr_t
, const __shared_ptr
<_Tp
, _Lp
>& __a
) noexcept
1239 { return std::less
<_Tp
*>()(nullptr, __a
.get()); }
1241 template<typename _Tp1
, typename _Tp2
, _Lock_policy _Lp
>
1243 operator<=(const __shared_ptr
<_Tp1
, _Lp
>& __a
,
1244 const __shared_ptr
<_Tp2
, _Lp
>& __b
) noexcept
1245 { return !(__b
< __a
); }
1247 template<typename _Tp
, _Lock_policy _Lp
>
1249 operator<=(const __shared_ptr
<_Tp
, _Lp
>& __a
, nullptr_t
) noexcept
1250 { return !(nullptr < __a
); }
1252 template<typename _Tp
, _Lock_policy _Lp
>
1254 operator<=(nullptr_t
, const __shared_ptr
<_Tp
, _Lp
>& __a
) noexcept
1255 { return !(__a
< nullptr); }
1257 template<typename _Tp1
, typename _Tp2
, _Lock_policy _Lp
>
1259 operator>(const __shared_ptr
<_Tp1
, _Lp
>& __a
,
1260 const __shared_ptr
<_Tp2
, _Lp
>& __b
) noexcept
1261 { return (__b
< __a
); }
1263 template<typename _Tp
, _Lock_policy _Lp
>
1265 operator>(const __shared_ptr
<_Tp
, _Lp
>& __a
, nullptr_t
) noexcept
1266 { return std::less
<_Tp
*>()(nullptr, __a
.get()); }
1268 template<typename _Tp
, _Lock_policy _Lp
>
1270 operator>(nullptr_t
, const __shared_ptr
<_Tp
, _Lp
>& __a
) noexcept
1271 { return std::less
<_Tp
*>()(__a
.get(), nullptr); }
1273 template<typename _Tp1
, typename _Tp2
, _Lock_policy _Lp
>
1275 operator>=(const __shared_ptr
<_Tp1
, _Lp
>& __a
,
1276 const __shared_ptr
<_Tp2
, _Lp
>& __b
) noexcept
1277 { return !(__a
< __b
); }
1279 template<typename _Tp
, _Lock_policy _Lp
>
1281 operator>=(const __shared_ptr
<_Tp
, _Lp
>& __a
, nullptr_t
) noexcept
1282 { return !(__a
< nullptr); }
1284 template<typename _Tp
, _Lock_policy _Lp
>
1286 operator>=(nullptr_t
, const __shared_ptr
<_Tp
, _Lp
>& __a
) noexcept
1287 { return !(nullptr < __a
); }
1289 template<typename _Sp
>
1290 struct _Sp_less
: public binary_function
<_Sp
, _Sp
, bool>
1293 operator()(const _Sp
& __lhs
, const _Sp
& __rhs
) const noexcept
1295 typedef typename
_Sp::element_type element_type
;
1296 return std::less
<element_type
*>()(__lhs
.get(), __rhs
.get());
1300 template<typename _Tp
, _Lock_policy _Lp
>
1301 struct less
<__shared_ptr
<_Tp
, _Lp
>>
1302 : public _Sp_less
<__shared_ptr
<_Tp
, _Lp
>>
1305 // 20.7.2.2.8 shared_ptr specialized algorithms.
1306 template<typename _Tp
, _Lock_policy _Lp
>
1308 swap(__shared_ptr
<_Tp
, _Lp
>& __a
, __shared_ptr
<_Tp
, _Lp
>& __b
) noexcept
1311 // 20.7.2.2.9 shared_ptr casts
1313 // The seemingly equivalent code:
1314 // shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get()))
1315 // will eventually result in undefined behaviour, attempting to
1316 // delete the same object twice.
1317 /// static_pointer_cast
1318 template<typename _Tp
, typename _Tp1
, _Lock_policy _Lp
>
1319 inline __shared_ptr
<_Tp
, _Lp
>
1320 static_pointer_cast(const __shared_ptr
<_Tp1
, _Lp
>& __r
) noexcept
1321 { return __shared_ptr
<_Tp
, _Lp
>(__r
, static_cast<_Tp
*>(__r
.get())); }
1323 // The seemingly equivalent code:
1324 // shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get()))
1325 // will eventually result in undefined behaviour, attempting to
1326 // delete the same object twice.
1327 /// const_pointer_cast
1328 template<typename _Tp
, typename _Tp1
, _Lock_policy _Lp
>
1329 inline __shared_ptr
<_Tp
, _Lp
>
1330 const_pointer_cast(const __shared_ptr
<_Tp1
, _Lp
>& __r
) noexcept
1331 { return __shared_ptr
<_Tp
, _Lp
>(__r
, const_cast<_Tp
*>(__r
.get())); }
1333 // The seemingly equivalent code:
1334 // shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get()))
1335 // will eventually result in undefined behaviour, attempting to
1336 // delete the same object twice.
1337 /// dynamic_pointer_cast
1338 template<typename _Tp
, typename _Tp1
, _Lock_policy _Lp
>
1339 inline __shared_ptr
<_Tp
, _Lp
>
1340 dynamic_pointer_cast(const __shared_ptr
<_Tp1
, _Lp
>& __r
) noexcept
1342 if (_Tp
* __p
= dynamic_cast<_Tp
*>(__r
.get()))
1343 return __shared_ptr
<_Tp
, _Lp
>(__r
, __p
);
1344 return __shared_ptr
<_Tp
, _Lp
>();
1348 template<typename _Tp
, _Lock_policy _Lp
>
1351 template<typename _Ptr
>
1353 = typename enable_if
<is_convertible
<_Ptr
, _Tp
*>::value
>::type
;
1356 typedef _Tp element_type
;
1358 constexpr __weak_ptr() noexcept
1359 : _M_ptr(nullptr), _M_refcount()
1362 __weak_ptr(const __weak_ptr
&) noexcept
= default;
1364 ~__weak_ptr() = default;
1366 // The "obvious" converting constructor implementation:
1368 // template<typename _Tp1>
1369 // __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
1370 // : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
1373 // has a serious problem.
1375 // __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr)
1376 // conversion may require access to *__r._M_ptr (virtual inheritance).
1378 // It is not possible to avoid spurious access violations since
1379 // in multithreaded programs __r._M_ptr may be invalidated at any point.
1380 template<typename _Tp1
, typename
= _Convertible
<_Tp1
*>>
1381 __weak_ptr(const __weak_ptr
<_Tp1
, _Lp
>& __r
) noexcept
1382 : _M_refcount(__r
._M_refcount
)
1383 { _M_ptr
= __r
.lock().get(); }
1385 template<typename _Tp1
, typename
= _Convertible
<_Tp1
*>>
1386 __weak_ptr(const __shared_ptr
<_Tp1
, _Lp
>& __r
) noexcept
1387 : _M_ptr(__r
._M_ptr
), _M_refcount(__r
._M_refcount
)
1390 __weak_ptr(__weak_ptr
&& __r
) noexcept
1391 : _M_ptr(__r
._M_ptr
), _M_refcount(std::move(__r
._M_refcount
))
1392 { __r
._M_ptr
= nullptr; }
1394 template<typename _Tp1
, typename
= _Convertible
<_Tp1
*>>
1395 __weak_ptr(__weak_ptr
<_Tp1
, _Lp
>&& __r
) noexcept
1396 : _M_ptr(__r
.lock().get()), _M_refcount(std::move(__r
._M_refcount
))
1397 { __r
._M_ptr
= nullptr; }
1400 operator=(const __weak_ptr
& __r
) noexcept
= default;
1402 template<typename _Tp1
>
1404 operator=(const __weak_ptr
<_Tp1
, _Lp
>& __r
) noexcept
1406 _M_ptr
= __r
.lock().get();
1407 _M_refcount
= __r
._M_refcount
;
1411 template<typename _Tp1
>
1413 operator=(const __shared_ptr
<_Tp1
, _Lp
>& __r
) noexcept
1415 _M_ptr
= __r
._M_ptr
;
1416 _M_refcount
= __r
._M_refcount
;
1421 operator=(__weak_ptr
&& __r
) noexcept
1423 _M_ptr
= __r
._M_ptr
;
1424 _M_refcount
= std::move(__r
._M_refcount
);
1425 __r
._M_ptr
= nullptr;
1429 template<typename _Tp1
>
1431 operator=(__weak_ptr
<_Tp1
, _Lp
>&& __r
) noexcept
1433 _M_ptr
= __r
.lock().get();
1434 _M_refcount
= std::move(__r
._M_refcount
);
1435 __r
._M_ptr
= nullptr;
1439 __shared_ptr
<_Tp
, _Lp
>
1440 lock() const noexcept
1441 { return __shared_ptr
<element_type
, _Lp
>(*this, std::nothrow
); }
1444 use_count() const noexcept
1445 { return _M_refcount
._M_get_use_count(); }
1448 expired() const noexcept
1449 { return _M_refcount
._M_get_use_count() == 0; }
1451 template<typename _Tp1
>
1453 owner_before(const __shared_ptr
<_Tp1
, _Lp
>& __rhs
) const
1454 { return _M_refcount
._M_less(__rhs
._M_refcount
); }
1456 template<typename _Tp1
>
1458 owner_before(const __weak_ptr
<_Tp1
, _Lp
>& __rhs
) const
1459 { return _M_refcount
._M_less(__rhs
._M_refcount
); }
1463 { __weak_ptr().swap(*this); }
1466 swap(__weak_ptr
& __s
) noexcept
1468 std::swap(_M_ptr
, __s
._M_ptr
);
1469 _M_refcount
._M_swap(__s
._M_refcount
);
1473 // Used by __enable_shared_from_this.
1475 _M_assign(_Tp
* __ptr
, const __shared_count
<_Lp
>& __refcount
) noexcept
1477 if (use_count() == 0)
1480 _M_refcount
= __refcount
;
1484 template<typename _Tp1
, _Lock_policy _Lp1
> friend class __shared_ptr
;
1485 template<typename _Tp1
, _Lock_policy _Lp1
> friend class __weak_ptr
;
1486 friend class __enable_shared_from_this
<_Tp
, _Lp
>;
1487 friend class enable_shared_from_this
<_Tp
>;
1489 _Tp
* _M_ptr
; // Contained pointer.
1490 __weak_count
<_Lp
> _M_refcount
; // Reference counter.
1493 // 20.7.2.3.6 weak_ptr specialized algorithms.
1494 template<typename _Tp
, _Lock_policy _Lp
>
1496 swap(__weak_ptr
<_Tp
, _Lp
>& __a
, __weak_ptr
<_Tp
, _Lp
>& __b
) noexcept
1499 template<typename _Tp
, typename _Tp1
>
1500 struct _Sp_owner_less
: public binary_function
<_Tp
, _Tp
, bool>
1503 operator()(const _Tp
& __lhs
, const _Tp
& __rhs
) const
1504 { return __lhs
.owner_before(__rhs
); }
1507 operator()(const _Tp
& __lhs
, const _Tp1
& __rhs
) const
1508 { return __lhs
.owner_before(__rhs
); }
1511 operator()(const _Tp1
& __lhs
, const _Tp
& __rhs
) const
1512 { return __lhs
.owner_before(__rhs
); }
1515 template<typename _Tp
, _Lock_policy _Lp
>
1516 struct owner_less
<__shared_ptr
<_Tp
, _Lp
>>
1517 : public _Sp_owner_less
<__shared_ptr
<_Tp
, _Lp
>, __weak_ptr
<_Tp
, _Lp
>>
1520 template<typename _Tp
, _Lock_policy _Lp
>
1521 struct owner_less
<__weak_ptr
<_Tp
, _Lp
>>
1522 : public _Sp_owner_less
<__weak_ptr
<_Tp
, _Lp
>, __shared_ptr
<_Tp
, _Lp
>>
1526 template<typename _Tp
, _Lock_policy _Lp
>
1527 class __enable_shared_from_this
1530 constexpr __enable_shared_from_this() noexcept
{ }
1532 __enable_shared_from_this(const __enable_shared_from_this
&) noexcept
{ }
1534 __enable_shared_from_this
&
1535 operator=(const __enable_shared_from_this
&) noexcept
1538 ~__enable_shared_from_this() { }
1541 __shared_ptr
<_Tp
, _Lp
>
1543 { return __shared_ptr
<_Tp
, _Lp
>(this->_M_weak_this
); }
1545 __shared_ptr
<const _Tp
, _Lp
>
1546 shared_from_this() const
1547 { return __shared_ptr
<const _Tp
, _Lp
>(this->_M_weak_this
); }
1550 template<typename _Tp1
>
1552 _M_weak_assign(_Tp1
* __p
, const __shared_count
<_Lp
>& __n
) const noexcept
1553 { _M_weak_this
._M_assign(__p
, __n
); }
1555 template<_Lock_policy _Lp1
, typename _Tp1
, typename _Tp2
>
1557 __enable_shared_from_this_helper(const __shared_count
<_Lp1
>&,
1558 const __enable_shared_from_this
<_Tp1
,
1559 _Lp1
>*, const _Tp2
*) noexcept
;
1561 mutable __weak_ptr
<_Tp
, _Lp
> _M_weak_this
;
1564 template<_Lock_policy _Lp1
, typename _Tp1
, typename _Tp2
>
1566 __enable_shared_from_this_helper(const __shared_count
<_Lp1
>& __pn
,
1567 const __enable_shared_from_this
<_Tp1
,
1569 const _Tp2
* __px
) noexcept
1571 if (__pe
!= nullptr)
1572 __pe
->_M_weak_assign(const_cast<_Tp2
*>(__px
), __pn
);
1575 template<typename _Tp
, _Lock_policy _Lp
, typename _Alloc
, typename
... _Args
>
1576 inline __shared_ptr
<_Tp
, _Lp
>
1577 __allocate_shared(const _Alloc
& __a
, _Args
&&... __args
)
1579 return __shared_ptr
<_Tp
, _Lp
>(_Sp_make_shared_tag(), __a
,
1580 std::forward
<_Args
>(__args
)...);
1583 template<typename _Tp
, _Lock_policy _Lp
, typename
... _Args
>
1584 inline __shared_ptr
<_Tp
, _Lp
>
1585 __make_shared(_Args
&&... __args
)
1587 typedef typename
std::remove_const
<_Tp
>::type _Tp_nc
;
1588 return std::__allocate_shared
<_Tp
, _Lp
>(std::allocator
<_Tp_nc
>(),
1589 std::forward
<_Args
>(__args
)...);
1592 /// std::hash specialization for __shared_ptr.
1593 template<typename _Tp
, _Lock_policy _Lp
>
1594 struct hash
<__shared_ptr
<_Tp
, _Lp
>>
1595 : public __hash_base
<size_t, __shared_ptr
<_Tp
, _Lp
>>
1598 operator()(const __shared_ptr
<_Tp
, _Lp
>& __s
) const noexcept
1599 { return std::hash
<_Tp
*>()(__s
.get()); }
1602 _GLIBCXX_END_NAMESPACE_VERSION
1605 #endif // _SHARED_PTR_BASE_H