libstdc++
shared_ptr_base.h
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1// shared_ptr and weak_ptr implementation details -*- C++ -*-
2
3// Copyright (C) 2007-2020 Free Software Foundation, Inc.
4//
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)
9// any later version.
10
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.
15
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.
19
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/>.
24
25// GCC Note: Based on files from version 1.32.0 of the Boost library.
26
27// shared_count.hpp
28// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
29
30// shared_ptr.hpp
31// Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.
32// Copyright (C) 2001, 2002, 2003 Peter Dimov
33
34// weak_ptr.hpp
35// Copyright (C) 2001, 2002, 2003 Peter Dimov
36
37// enable_shared_from_this.hpp
38// Copyright (C) 2002 Peter Dimov
39
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)
43
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}
47 */
48
49#ifndef _SHARED_PTR_BASE_H
50#define _SHARED_PTR_BASE_H 1
51
52#include <typeinfo>
53#include <bits/allocated_ptr.h>
54#include <bits/refwrap.h>
55#include <bits/stl_function.h>
56#include <ext/aligned_buffer.h>
57#if __cplusplus > 201703L
58# include <compare>
59#endif
60
61namespace std _GLIBCXX_VISIBILITY(default)
62{
63_GLIBCXX_BEGIN_NAMESPACE_VERSION
64
65#if _GLIBCXX_USE_DEPRECATED
66#pragma GCC diagnostic push
67#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
68 template<typename> class auto_ptr;
69#pragma GCC diagnostic pop
70#endif
71
72 /**
73 * @brief Exception possibly thrown by @c shared_ptr.
74 * @ingroup exceptions
75 */
77 {
78 public:
79 virtual char const* what() const noexcept;
80
81 virtual ~bad_weak_ptr() noexcept;
82 };
83
84 // Substitute for bad_weak_ptr object in the case of -fno-exceptions.
85 inline void
86 __throw_bad_weak_ptr()
87 { _GLIBCXX_THROW_OR_ABORT(bad_weak_ptr()); }
88
89 using __gnu_cxx::_Lock_policy;
90 using __gnu_cxx::__default_lock_policy;
91 using __gnu_cxx::_S_single;
92 using __gnu_cxx::_S_mutex;
93 using __gnu_cxx::_S_atomic;
94
95 // Empty helper class except when the template argument is _S_mutex.
96 template<_Lock_policy _Lp>
97 class _Mutex_base
98 {
99 protected:
100 // The atomic policy uses fully-fenced builtins, single doesn't care.
101 enum { _S_need_barriers = 0 };
102 };
103
104 template<>
105 class _Mutex_base<_S_mutex>
106 : public __gnu_cxx::__mutex
107 {
108 protected:
109 // This policy is used when atomic builtins are not available.
110 // The replacement atomic operations might not have the necessary
111 // memory barriers.
112 enum { _S_need_barriers = 1 };
113 };
114
115 template<_Lock_policy _Lp = __default_lock_policy>
116 class _Sp_counted_base
117 : public _Mutex_base<_Lp>
118 {
119 public:
120 _Sp_counted_base() noexcept
121 : _M_use_count(1), _M_weak_count(1) { }
122
123 virtual
124 ~_Sp_counted_base() noexcept
125 { }
126
127 // Called when _M_use_count drops to zero, to release the resources
128 // managed by *this.
129 virtual void
130 _M_dispose() noexcept = 0;
131
132 // Called when _M_weak_count drops to zero.
133 virtual void
134 _M_destroy() noexcept
135 { delete this; }
136
137 virtual void*
138 _M_get_deleter(const std::type_info&) noexcept = 0;
139
140 void
141 _M_add_ref_copy()
142 { __gnu_cxx::__atomic_add_dispatch(&_M_use_count, 1); }
143
144 void
145 _M_add_ref_lock();
146
147 bool
148 _M_add_ref_lock_nothrow();
149
150 void
151 _M_release() noexcept
152 {
153 // Be race-detector-friendly. For more info see bits/c++config.
154 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count);
155 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1)
156 {
157 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count);
158 _M_dispose();
159 // There must be a memory barrier between dispose() and destroy()
160 // to ensure that the effects of dispose() are observed in the
161 // thread that runs destroy().
162 // See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html
163 if (_Mutex_base<_Lp>::_S_need_barriers)
164 {
165 __atomic_thread_fence (__ATOMIC_ACQ_REL);
166 }
167
168 // Be race-detector-friendly. For more info see bits/c++config.
169 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
170 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count,
171 -1) == 1)
172 {
173 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
174 _M_destroy();
175 }
176 }
177 }
178
179 void
180 _M_weak_add_ref() noexcept
181 { __gnu_cxx::__atomic_add_dispatch(&_M_weak_count, 1); }
182
183 void
184 _M_weak_release() noexcept
185 {
186 // Be race-detector-friendly. For more info see bits/c++config.
187 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
188 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, -1) == 1)
189 {
190 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
191 if (_Mutex_base<_Lp>::_S_need_barriers)
192 {
193 // See _M_release(),
194 // destroy() must observe results of dispose()
195 __atomic_thread_fence (__ATOMIC_ACQ_REL);
196 }
197 _M_destroy();
198 }
199 }
200
201 long
202 _M_get_use_count() const noexcept
203 {
204 // No memory barrier is used here so there is no synchronization
205 // with other threads.
206 return __atomic_load_n(&_M_use_count, __ATOMIC_RELAXED);
207 }
208
209 private:
210 _Sp_counted_base(_Sp_counted_base const&) = delete;
211 _Sp_counted_base& operator=(_Sp_counted_base const&) = delete;
212
213 _Atomic_word _M_use_count; // #shared
214 _Atomic_word _M_weak_count; // #weak + (#shared != 0)
215 };
216
217 template<>
218 inline void
219 _Sp_counted_base<_S_single>::
220 _M_add_ref_lock()
221 {
222 if (_M_use_count == 0)
223 __throw_bad_weak_ptr();
224 ++_M_use_count;
225 }
226
227 template<>
228 inline void
229 _Sp_counted_base<_S_mutex>::
230 _M_add_ref_lock()
231 {
232 __gnu_cxx::__scoped_lock sentry(*this);
233 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0)
234 {
235 _M_use_count = 0;
236 __throw_bad_weak_ptr();
237 }
238 }
239
240 template<>
241 inline void
242 _Sp_counted_base<_S_atomic>::
243 _M_add_ref_lock()
244 {
245 // Perform lock-free add-if-not-zero operation.
246 _Atomic_word __count = _M_get_use_count();
247 do
248 {
249 if (__count == 0)
250 __throw_bad_weak_ptr();
251 // Replace the current counter value with the old value + 1, as
252 // long as it's not changed meanwhile.
253 }
254 while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1,
255 true, __ATOMIC_ACQ_REL,
256 __ATOMIC_RELAXED));
257 }
258
259 template<>
260 inline bool
261 _Sp_counted_base<_S_single>::
262 _M_add_ref_lock_nothrow()
263 {
264 if (_M_use_count == 0)
265 return false;
266 ++_M_use_count;
267 return true;
268 }
269
270 template<>
271 inline bool
272 _Sp_counted_base<_S_mutex>::
273 _M_add_ref_lock_nothrow()
274 {
275 __gnu_cxx::__scoped_lock sentry(*this);
276 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0)
277 {
278 _M_use_count = 0;
279 return false;
280 }
281 return true;
282 }
283
284 template<>
285 inline bool
286 _Sp_counted_base<_S_atomic>::
287 _M_add_ref_lock_nothrow()
288 {
289 // Perform lock-free add-if-not-zero operation.
290 _Atomic_word __count = _M_get_use_count();
291 do
292 {
293 if (__count == 0)
294 return false;
295 // Replace the current counter value with the old value + 1, as
296 // long as it's not changed meanwhile.
297 }
298 while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1,
299 true, __ATOMIC_ACQ_REL,
300 __ATOMIC_RELAXED));
301 return true;
302 }
303
304 template<>
305 inline void
306 _Sp_counted_base<_S_single>::_M_add_ref_copy()
307 { ++_M_use_count; }
308
309 template<>
310 inline void
311 _Sp_counted_base<_S_single>::_M_release() noexcept
312 {
313 if (--_M_use_count == 0)
314 {
315 _M_dispose();
316 if (--_M_weak_count == 0)
317 _M_destroy();
318 }
319 }
320
321 template<>
322 inline void
323 _Sp_counted_base<_S_single>::_M_weak_add_ref() noexcept
324 { ++_M_weak_count; }
325
326 template<>
327 inline void
328 _Sp_counted_base<_S_single>::_M_weak_release() noexcept
329 {
330 if (--_M_weak_count == 0)
331 _M_destroy();
332 }
333
334 template<>
335 inline long
336 _Sp_counted_base<_S_single>::_M_get_use_count() const noexcept
337 { return _M_use_count; }
338
339
340 // Forward declarations.
341 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
342 class __shared_ptr;
343
344 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
345 class __weak_ptr;
346
347 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
348 class __enable_shared_from_this;
349
350 template<typename _Tp>
351 class shared_ptr;
352
353 template<typename _Tp>
354 class weak_ptr;
355
356 template<typename _Tp>
357 struct owner_less;
358
359 template<typename _Tp>
360 class enable_shared_from_this;
361
362 template<_Lock_policy _Lp = __default_lock_policy>
363 class __weak_count;
364
365 template<_Lock_policy _Lp = __default_lock_policy>
366 class __shared_count;
367
368
369 // Counted ptr with no deleter or allocator support
370 template<typename _Ptr, _Lock_policy _Lp>
371 class _Sp_counted_ptr final : public _Sp_counted_base<_Lp>
372 {
373 public:
374 explicit
375 _Sp_counted_ptr(_Ptr __p) noexcept
376 : _M_ptr(__p) { }
377
378 virtual void
379 _M_dispose() noexcept
380 { delete _M_ptr; }
381
382 virtual void
383 _M_destroy() noexcept
384 { delete this; }
385
386 virtual void*
387 _M_get_deleter(const std::type_info&) noexcept
388 { return nullptr; }
389
390 _Sp_counted_ptr(const _Sp_counted_ptr&) = delete;
391 _Sp_counted_ptr& operator=(const _Sp_counted_ptr&) = delete;
392
393 private:
394 _Ptr _M_ptr;
395 };
396
397 template<>
398 inline void
399 _Sp_counted_ptr<nullptr_t, _S_single>::_M_dispose() noexcept { }
400
401 template<>
402 inline void
403 _Sp_counted_ptr<nullptr_t, _S_mutex>::_M_dispose() noexcept { }
404
405 template<>
406 inline void
407 _Sp_counted_ptr<nullptr_t, _S_atomic>::_M_dispose() noexcept { }
408
409 template<int _Nm, typename _Tp,
410 bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
411 struct _Sp_ebo_helper;
412
413 /// Specialization using EBO.
414 template<int _Nm, typename _Tp>
415 struct _Sp_ebo_helper<_Nm, _Tp, true> : private _Tp
416 {
417 explicit _Sp_ebo_helper(const _Tp& __tp) : _Tp(__tp) { }
418 explicit _Sp_ebo_helper(_Tp&& __tp) : _Tp(std::move(__tp)) { }
419
420 static _Tp&
421 _S_get(_Sp_ebo_helper& __eboh) { return static_cast<_Tp&>(__eboh); }
422 };
423
424 /// Specialization not using EBO.
425 template<int _Nm, typename _Tp>
426 struct _Sp_ebo_helper<_Nm, _Tp, false>
427 {
428 explicit _Sp_ebo_helper(const _Tp& __tp) : _M_tp(__tp) { }
429 explicit _Sp_ebo_helper(_Tp&& __tp) : _M_tp(std::move(__tp)) { }
430
431 static _Tp&
432 _S_get(_Sp_ebo_helper& __eboh)
433 { return __eboh._M_tp; }
434
435 private:
436 _Tp _M_tp;
437 };
438
439 // Support for custom deleter and/or allocator
440 template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp>
441 class _Sp_counted_deleter final : public _Sp_counted_base<_Lp>
442 {
443 class _Impl : _Sp_ebo_helper<0, _Deleter>, _Sp_ebo_helper<1, _Alloc>
444 {
445 typedef _Sp_ebo_helper<0, _Deleter> _Del_base;
446 typedef _Sp_ebo_helper<1, _Alloc> _Alloc_base;
447
448 public:
449 _Impl(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
450 : _M_ptr(__p), _Del_base(std::move(__d)), _Alloc_base(__a)
451 { }
452
453 _Deleter& _M_del() noexcept { return _Del_base::_S_get(*this); }
454 _Alloc& _M_alloc() noexcept { return _Alloc_base::_S_get(*this); }
455
456 _Ptr _M_ptr;
457 };
458
459 public:
460 using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_deleter>;
461
462 // __d(__p) must not throw.
463 _Sp_counted_deleter(_Ptr __p, _Deleter __d) noexcept
464 : _M_impl(__p, std::move(__d), _Alloc()) { }
465
466 // __d(__p) must not throw.
467 _Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
468 : _M_impl(__p, std::move(__d), __a) { }
469
470 ~_Sp_counted_deleter() noexcept { }
471
472 virtual void
473 _M_dispose() noexcept
474 { _M_impl._M_del()(_M_impl._M_ptr); }
475
476 virtual void
477 _M_destroy() noexcept
478 {
479 __allocator_type __a(_M_impl._M_alloc());
480 __allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
481 this->~_Sp_counted_deleter();
482 }
483
484 virtual void*
485 _M_get_deleter(const std::type_info& __ti) noexcept
486 {
487#if __cpp_rtti
488 // _GLIBCXX_RESOLVE_LIB_DEFECTS
489 // 2400. shared_ptr's get_deleter() should use addressof()
490 return __ti == typeid(_Deleter)
491 ? std::__addressof(_M_impl._M_del())
492 : nullptr;
493#else
494 return nullptr;
495#endif
496 }
497
498 private:
499 _Impl _M_impl;
500 };
501
502 // helpers for make_shared / allocate_shared
503
504 struct _Sp_make_shared_tag
505 {
506 private:
507 template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
508 friend class _Sp_counted_ptr_inplace;
509
510 static const type_info&
511 _S_ti() noexcept _GLIBCXX_VISIBILITY(default)
512 {
513 alignas(type_info) static constexpr char __tag[sizeof(type_info)] = { };
514 return reinterpret_cast<const type_info&>(__tag);
515 }
516
517 static bool _S_eq(const type_info&) noexcept;
518 };
519
520 template<typename _Alloc>
521 struct _Sp_alloc_shared_tag
522 {
523 const _Alloc& _M_a;
524 };
525
526 template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
527 class _Sp_counted_ptr_inplace final : public _Sp_counted_base<_Lp>
528 {
529 class _Impl : _Sp_ebo_helper<0, _Alloc>
530 {
531 typedef _Sp_ebo_helper<0, _Alloc> _A_base;
532
533 public:
534 explicit _Impl(_Alloc __a) noexcept : _A_base(__a) { }
535
536 _Alloc& _M_alloc() noexcept { return _A_base::_S_get(*this); }
537
538 __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
539 };
540
541 public:
542 using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_ptr_inplace>;
543
544 // Alloc parameter is not a reference so doesn't alias anything in __args
545 template<typename... _Args>
546 _Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args)
547 : _M_impl(__a)
548 {
549 // _GLIBCXX_RESOLVE_LIB_DEFECTS
550 // 2070. allocate_shared should use allocator_traits<A>::construct
552 std::forward<_Args>(__args)...); // might throw
553 }
554
555 ~_Sp_counted_ptr_inplace() noexcept { }
556
557 virtual void
558 _M_dispose() noexcept
559 {
560 allocator_traits<_Alloc>::destroy(_M_impl._M_alloc(), _M_ptr());
561 }
562
563 // Override because the allocator needs to know the dynamic type
564 virtual void
565 _M_destroy() noexcept
566 {
567 __allocator_type __a(_M_impl._M_alloc());
568 __allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
569 this->~_Sp_counted_ptr_inplace();
570 }
571
572 private:
573 friend class __shared_count<_Lp>; // To be able to call _M_ptr().
574
575 // No longer used, but code compiled against old libstdc++ headers
576 // might still call it from __shared_ptr ctor to get the pointer out.
577 virtual void*
578 _M_get_deleter(const std::type_info& __ti) noexcept override
579 {
580 auto __ptr = const_cast<typename remove_cv<_Tp>::type*>(_M_ptr());
581 // Check for the fake type_info first, so we don't try to access it
582 // as a real type_info object. Otherwise, check if it's the real
583 // type_info for this class. With RTTI enabled we can check directly,
584 // or call a library function to do it.
585 if (&__ti == &_Sp_make_shared_tag::_S_ti()
586 ||
587#if __cpp_rtti
588 __ti == typeid(_Sp_make_shared_tag)
589#else
590 _Sp_make_shared_tag::_S_eq(__ti)
591#endif
592 )
593 return __ptr;
594 return nullptr;
595 }
596
597 _Tp* _M_ptr() noexcept { return _M_impl._M_storage._M_ptr(); }
598
599 _Impl _M_impl;
600 };
601
602 // The default deleter for shared_ptr<T[]> and shared_ptr<T[N]>.
603 struct __sp_array_delete
604 {
605 template<typename _Yp>
606 void operator()(_Yp* __p) const { delete[] __p; }
607 };
608
609 template<_Lock_policy _Lp>
610 class __shared_count
611 {
612 template<typename _Tp>
613 struct __not_alloc_shared_tag { using type = void; };
614
615 template<typename _Tp>
616 struct __not_alloc_shared_tag<_Sp_alloc_shared_tag<_Tp>> { };
617
618 public:
619 constexpr __shared_count() noexcept : _M_pi(0)
620 { }
621
622 template<typename _Ptr>
623 explicit
624 __shared_count(_Ptr __p) : _M_pi(0)
625 {
626 __try
627 {
628 _M_pi = new _Sp_counted_ptr<_Ptr, _Lp>(__p);
629 }
630 __catch(...)
631 {
632 delete __p;
633 __throw_exception_again;
634 }
635 }
636
637 template<typename _Ptr>
638 __shared_count(_Ptr __p, /* is_array = */ false_type)
639 : __shared_count(__p)
640 { }
641
642 template<typename _Ptr>
643 __shared_count(_Ptr __p, /* is_array = */ true_type)
644 : __shared_count(__p, __sp_array_delete{}, allocator<void>())
645 { }
646
647 template<typename _Ptr, typename _Deleter,
648 typename = typename __not_alloc_shared_tag<_Deleter>::type>
649 __shared_count(_Ptr __p, _Deleter __d)
650 : __shared_count(__p, std::move(__d), allocator<void>())
651 { }
652
653 template<typename _Ptr, typename _Deleter, typename _Alloc,
654 typename = typename __not_alloc_shared_tag<_Deleter>::type>
655 __shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0)
656 {
657 typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
658 __try
659 {
660 typename _Sp_cd_type::__allocator_type __a2(__a);
661 auto __guard = std::__allocate_guarded(__a2);
662 _Sp_cd_type* __mem = __guard.get();
663 ::new (__mem) _Sp_cd_type(__p, std::move(__d), std::move(__a));
664 _M_pi = __mem;
665 __guard = nullptr;
666 }
667 __catch(...)
668 {
669 __d(__p); // Call _Deleter on __p.
670 __throw_exception_again;
671 }
672 }
673
674 template<typename _Tp, typename _Alloc, typename... _Args>
675 __shared_count(_Tp*& __p, _Sp_alloc_shared_tag<_Alloc> __a,
676 _Args&&... __args)
677 {
678 typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type;
679 typename _Sp_cp_type::__allocator_type __a2(__a._M_a);
680 auto __guard = std::__allocate_guarded(__a2);
681 _Sp_cp_type* __mem = __guard.get();
682 auto __pi = ::new (__mem)
683 _Sp_cp_type(__a._M_a, std::forward<_Args>(__args)...);
684 __guard = nullptr;
685 _M_pi = __pi;
686 __p = __pi->_M_ptr();
687 }
688
689#if _GLIBCXX_USE_DEPRECATED
690#pragma GCC diagnostic push
691#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
692 // Special case for auto_ptr<_Tp> to provide the strong guarantee.
693 template<typename _Tp>
694 explicit
695 __shared_count(std::auto_ptr<_Tp>&& __r);
696#pragma GCC diagnostic pop
697#endif
698
699 // Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee.
700 template<typename _Tp, typename _Del>
701 explicit
702 __shared_count(std::unique_ptr<_Tp, _Del>&& __r) : _M_pi(0)
703 {
704 // _GLIBCXX_RESOLVE_LIB_DEFECTS
705 // 2415. Inconsistency between unique_ptr and shared_ptr
706 if (__r.get() == nullptr)
707 return;
708
709 using _Ptr = typename unique_ptr<_Tp, _Del>::pointer;
710 using _Del2 = typename conditional<is_reference<_Del>::value,
711 reference_wrapper<typename remove_reference<_Del>::type>,
712 _Del>::type;
713 using _Sp_cd_type
714 = _Sp_counted_deleter<_Ptr, _Del2, allocator<void>, _Lp>;
715 using _Alloc = allocator<_Sp_cd_type>;
716 using _Alloc_traits = allocator_traits<_Alloc>;
717 _Alloc __a;
718 _Sp_cd_type* __mem = _Alloc_traits::allocate(__a, 1);
719 // _GLIBCXX_RESOLVE_LIB_DEFECTS
720 // 3548. shared_ptr construction from unique_ptr should move
721 // (not copy) the deleter
722 _Alloc_traits::construct(__a, __mem, __r.release(),
723 std::forward<_Del>(__r.get_deleter()));
724 _M_pi = __mem;
725 }
726
727 // Throw bad_weak_ptr when __r._M_get_use_count() == 0.
728 explicit __shared_count(const __weak_count<_Lp>& __r);
729
730 // Does not throw if __r._M_get_use_count() == 0, caller must check.
731 explicit __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t);
732
733 ~__shared_count() noexcept
734 {
735 if (_M_pi != nullptr)
736 _M_pi->_M_release();
737 }
738
739 __shared_count(const __shared_count& __r) noexcept
740 : _M_pi(__r._M_pi)
741 {
742 if (_M_pi != 0)
743 _M_pi->_M_add_ref_copy();
744 }
745
746 __shared_count&
747 operator=(const __shared_count& __r) noexcept
748 {
749 _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
750 if (__tmp != _M_pi)
751 {
752 if (__tmp != 0)
753 __tmp->_M_add_ref_copy();
754 if (_M_pi != 0)
755 _M_pi->_M_release();
756 _M_pi = __tmp;
757 }
758 return *this;
759 }
760
761 void
762 _M_swap(__shared_count& __r) noexcept
763 {
764 _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
765 __r._M_pi = _M_pi;
766 _M_pi = __tmp;
767 }
768
769 long
770 _M_get_use_count() const noexcept
771 { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; }
772
773 bool
774 _M_unique() const noexcept
775 { return this->_M_get_use_count() == 1; }
776
777 void*
778 _M_get_deleter(const std::type_info& __ti) const noexcept
779 { return _M_pi ? _M_pi->_M_get_deleter(__ti) : nullptr; }
780
781 bool
782 _M_less(const __shared_count& __rhs) const noexcept
783 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
784
785 bool
786 _M_less(const __weak_count<_Lp>& __rhs) const noexcept
787 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
788
789 // Friend function injected into enclosing namespace and found by ADL
790 friend inline bool
791 operator==(const __shared_count& __a, const __shared_count& __b) noexcept
792 { return __a._M_pi == __b._M_pi; }
793
794 private:
795 friend class __weak_count<_Lp>;
796
797 _Sp_counted_base<_Lp>* _M_pi;
798 };
799
800
801 template<_Lock_policy _Lp>
802 class __weak_count
803 {
804 public:
805 constexpr __weak_count() noexcept : _M_pi(nullptr)
806 { }
807
808 __weak_count(const __shared_count<_Lp>& __r) noexcept
809 : _M_pi(__r._M_pi)
810 {
811 if (_M_pi != nullptr)
812 _M_pi->_M_weak_add_ref();
813 }
814
815 __weak_count(const __weak_count& __r) noexcept
816 : _M_pi(__r._M_pi)
817 {
818 if (_M_pi != nullptr)
819 _M_pi->_M_weak_add_ref();
820 }
821
822 __weak_count(__weak_count&& __r) noexcept
823 : _M_pi(__r._M_pi)
824 { __r._M_pi = nullptr; }
825
826 ~__weak_count() noexcept
827 {
828 if (_M_pi != nullptr)
829 _M_pi->_M_weak_release();
830 }
831
832 __weak_count&
833 operator=(const __shared_count<_Lp>& __r) noexcept
834 {
835 _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
836 if (__tmp != nullptr)
837 __tmp->_M_weak_add_ref();
838 if (_M_pi != nullptr)
839 _M_pi->_M_weak_release();
840 _M_pi = __tmp;
841 return *this;
842 }
843
844 __weak_count&
845 operator=(const __weak_count& __r) noexcept
846 {
847 _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
848 if (__tmp != nullptr)
849 __tmp->_M_weak_add_ref();
850 if (_M_pi != nullptr)
851 _M_pi->_M_weak_release();
852 _M_pi = __tmp;
853 return *this;
854 }
855
856 __weak_count&
857 operator=(__weak_count&& __r) noexcept
858 {
859 if (_M_pi != nullptr)
860 _M_pi->_M_weak_release();
861 _M_pi = __r._M_pi;
862 __r._M_pi = nullptr;
863 return *this;
864 }
865
866 void
867 _M_swap(__weak_count& __r) noexcept
868 {
869 _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
870 __r._M_pi = _M_pi;
871 _M_pi = __tmp;
872 }
873
874 long
875 _M_get_use_count() const noexcept
876 { return _M_pi != nullptr ? _M_pi->_M_get_use_count() : 0; }
877
878 bool
879 _M_less(const __weak_count& __rhs) const noexcept
880 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
881
882 bool
883 _M_less(const __shared_count<_Lp>& __rhs) const noexcept
884 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
885
886 // Friend function injected into enclosing namespace and found by ADL
887 friend inline bool
888 operator==(const __weak_count& __a, const __weak_count& __b) noexcept
889 { return __a._M_pi == __b._M_pi; }
890
891 private:
892 friend class __shared_count<_Lp>;
893
894 _Sp_counted_base<_Lp>* _M_pi;
895 };
896
897 // Now that __weak_count is defined we can define this constructor:
898 template<_Lock_policy _Lp>
899 inline
900 __shared_count<_Lp>::__shared_count(const __weak_count<_Lp>& __r)
901 : _M_pi(__r._M_pi)
902 {
903 if (_M_pi != nullptr)
904 _M_pi->_M_add_ref_lock();
905 else
906 __throw_bad_weak_ptr();
907 }
908
909 // Now that __weak_count is defined we can define this constructor:
910 template<_Lock_policy _Lp>
911 inline
912 __shared_count<_Lp>::
913 __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t)
914 : _M_pi(__r._M_pi)
915 {
916 if (_M_pi != nullptr)
917 if (!_M_pi->_M_add_ref_lock_nothrow())
918 _M_pi = nullptr;
919 }
920
921#define __cpp_lib_shared_ptr_arrays 201611L
922
923 // Helper traits for shared_ptr of array:
924
925 // A pointer type Y* is said to be compatible with a pointer type T* when
926 // either Y* is convertible to T* or Y is U[N] and T is U cv [].
927 template<typename _Yp_ptr, typename _Tp_ptr>
928 struct __sp_compatible_with
929 : false_type
930 { };
931
932 template<typename _Yp, typename _Tp>
933 struct __sp_compatible_with<_Yp*, _Tp*>
934 : is_convertible<_Yp*, _Tp*>::type
935 { };
936
937 template<typename _Up, size_t _Nm>
938 struct __sp_compatible_with<_Up(*)[_Nm], _Up(*)[]>
939 : true_type
940 { };
941
942 template<typename _Up, size_t _Nm>
943 struct __sp_compatible_with<_Up(*)[_Nm], const _Up(*)[]>
944 : true_type
945 { };
946
947 template<typename _Up, size_t _Nm>
948 struct __sp_compatible_with<_Up(*)[_Nm], volatile _Up(*)[]>
949 : true_type
950 { };
951
952 template<typename _Up, size_t _Nm>
953 struct __sp_compatible_with<_Up(*)[_Nm], const volatile _Up(*)[]>
954 : true_type
955 { };
956
957 // Test conversion from Y(*)[N] to U(*)[N] without forming invalid type Y[N].
958 template<typename _Up, size_t _Nm, typename _Yp, typename = void>
959 struct __sp_is_constructible_arrN
960 : false_type
961 { };
962
963 template<typename _Up, size_t _Nm, typename _Yp>
964 struct __sp_is_constructible_arrN<_Up, _Nm, _Yp, __void_t<_Yp[_Nm]>>
965 : is_convertible<_Yp(*)[_Nm], _Up(*)[_Nm]>::type
966 { };
967
968 // Test conversion from Y(*)[] to U(*)[] without forming invalid type Y[].
969 template<typename _Up, typename _Yp, typename = void>
970 struct __sp_is_constructible_arr
971 : false_type
972 { };
973
974 template<typename _Up, typename _Yp>
975 struct __sp_is_constructible_arr<_Up, _Yp, __void_t<_Yp[]>>
976 : is_convertible<_Yp(*)[], _Up(*)[]>::type
977 { };
978
979 // Trait to check if shared_ptr<T> can be constructed from Y*.
980 template<typename _Tp, typename _Yp>
981 struct __sp_is_constructible;
982
983 // When T is U[N], Y(*)[N] shall be convertible to T*;
984 template<typename _Up, size_t _Nm, typename _Yp>
985 struct __sp_is_constructible<_Up[_Nm], _Yp>
986 : __sp_is_constructible_arrN<_Up, _Nm, _Yp>::type
987 { };
988
989 // when T is U[], Y(*)[] shall be convertible to T*;
990 template<typename _Up, typename _Yp>
991 struct __sp_is_constructible<_Up[], _Yp>
992 : __sp_is_constructible_arr<_Up, _Yp>::type
993 { };
994
995 // otherwise, Y* shall be convertible to T*.
996 template<typename _Tp, typename _Yp>
997 struct __sp_is_constructible
998 : is_convertible<_Yp*, _Tp*>::type
999 { };
1000
1001
1002 // Define operator* and operator-> for shared_ptr<T>.
1003 template<typename _Tp, _Lock_policy _Lp,
1004 bool = is_array<_Tp>::value, bool = is_void<_Tp>::value>
1005 class __shared_ptr_access
1006 {
1007 public:
1008 using element_type = _Tp;
1009
1010 element_type&
1011 operator*() const noexcept
1012 {
1013 __glibcxx_assert(_M_get() != nullptr);
1014 return *_M_get();
1015 }
1016
1017 element_type*
1018 operator->() const noexcept
1019 {
1020 _GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr);
1021 return _M_get();
1022 }
1023
1024 private:
1025 element_type*
1026 _M_get() const noexcept
1027 { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); }
1028 };
1029
1030 // Define operator-> for shared_ptr<cv void>.
1031 template<typename _Tp, _Lock_policy _Lp>
1032 class __shared_ptr_access<_Tp, _Lp, false, true>
1033 {
1034 public:
1035 using element_type = _Tp;
1036
1037 element_type*
1038 operator->() const noexcept
1039 {
1040 auto __ptr = static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get();
1041 _GLIBCXX_DEBUG_PEDASSERT(__ptr != nullptr);
1042 return __ptr;
1043 }
1044 };
1045
1046 // Define operator[] for shared_ptr<T[]> and shared_ptr<T[N]>.
1047 template<typename _Tp, _Lock_policy _Lp>
1048 class __shared_ptr_access<_Tp, _Lp, true, false>
1049 {
1050 public:
1051 using element_type = typename remove_extent<_Tp>::type;
1052
1053#if __cplusplus <= 201402L
1054 [[__deprecated__("shared_ptr<T[]>::operator* is absent from C++17")]]
1055 element_type&
1056 operator*() const noexcept
1057 {
1058 __glibcxx_assert(_M_get() != nullptr);
1059 return *_M_get();
1060 }
1061
1062 [[__deprecated__("shared_ptr<T[]>::operator-> is absent from C++17")]]
1063 element_type*
1064 operator->() const noexcept
1065 {
1066 _GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr);
1067 return _M_get();
1068 }
1069#endif
1070
1071 element_type&
1072 operator[](ptrdiff_t __i) const
1073 {
1074 __glibcxx_assert(_M_get() != nullptr);
1075 __glibcxx_assert(!extent<_Tp>::value || __i < extent<_Tp>::value);
1076 return _M_get()[__i];
1077 }
1078
1079 private:
1080 element_type*
1081 _M_get() const noexcept
1082 { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); }
1083 };
1084
1085 template<typename _Tp, _Lock_policy _Lp>
1086 class __shared_ptr
1087 : public __shared_ptr_access<_Tp, _Lp>
1088 {
1089 public:
1090 using element_type = typename remove_extent<_Tp>::type;
1091
1092 private:
1093 // Constraint for taking ownership of a pointer of type _Yp*:
1094 template<typename _Yp>
1095 using _SafeConv
1096 = typename enable_if<__sp_is_constructible<_Tp, _Yp>::value>::type;
1097
1098 // Constraint for construction from shared_ptr and weak_ptr:
1099 template<typename _Yp, typename _Res = void>
1100 using _Compatible = typename
1101 enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type;
1102
1103 // Constraint for assignment from shared_ptr and weak_ptr:
1104 template<typename _Yp>
1105 using _Assignable = _Compatible<_Yp, __shared_ptr&>;
1106
1107 // Constraint for construction from unique_ptr:
1108 template<typename _Yp, typename _Del, typename _Res = void,
1109 typename _Ptr = typename unique_ptr<_Yp, _Del>::pointer>
1110 using _UniqCompatible = __enable_if_t<__and_<
1111 __sp_compatible_with<_Yp*, _Tp*>,
1112 is_convertible<_Ptr, element_type*>,
1113 is_move_constructible<_Del>
1114 >::value, _Res>;
1115
1116 // Constraint for assignment from unique_ptr:
1117 template<typename _Yp, typename _Del>
1118 using _UniqAssignable = _UniqCompatible<_Yp, _Del, __shared_ptr&>;
1119
1120 public:
1121
1122#if __cplusplus > 201402L
1123 using weak_type = __weak_ptr<_Tp, _Lp>;
1124#endif
1125
1126 constexpr __shared_ptr() noexcept
1127 : _M_ptr(0), _M_refcount()
1128 { }
1129
1130 template<typename _Yp, typename = _SafeConv<_Yp>>
1131 explicit
1132 __shared_ptr(_Yp* __p)
1133 : _M_ptr(__p), _M_refcount(__p, typename is_array<_Tp>::type())
1134 {
1135 static_assert( !is_void<_Yp>::value, "incomplete type" );
1136 static_assert( sizeof(_Yp) > 0, "incomplete type" );
1137 _M_enable_shared_from_this_with(__p);
1138 }
1139
1140 template<typename _Yp, typename _Deleter, typename = _SafeConv<_Yp>>
1141 __shared_ptr(_Yp* __p, _Deleter __d)
1142 : _M_ptr(__p), _M_refcount(__p, std::move(__d))
1143 {
1144 static_assert(__is_invocable<_Deleter&, _Yp*&>::value,
1145 "deleter expression d(p) is well-formed");
1146 _M_enable_shared_from_this_with(__p);
1147 }
1148
1149 template<typename _Yp, typename _Deleter, typename _Alloc,
1150 typename = _SafeConv<_Yp>>
1151 __shared_ptr(_Yp* __p, _Deleter __d, _Alloc __a)
1152 : _M_ptr(__p), _M_refcount(__p, std::move(__d), std::move(__a))
1153 {
1154 static_assert(__is_invocable<_Deleter&, _Yp*&>::value,
1155 "deleter expression d(p) is well-formed");
1156 _M_enable_shared_from_this_with(__p);
1157 }
1158
1159 template<typename _Deleter>
1160 __shared_ptr(nullptr_t __p, _Deleter __d)
1161 : _M_ptr(0), _M_refcount(__p, std::move(__d))
1162 { }
1163
1164 template<typename _Deleter, typename _Alloc>
1165 __shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
1166 : _M_ptr(0), _M_refcount(__p, std::move(__d), std::move(__a))
1167 { }
1168
1169 // Aliasing constructor
1170 template<typename _Yp>
1171 __shared_ptr(const __shared_ptr<_Yp, _Lp>& __r,
1172 element_type* __p) noexcept
1173 : _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws
1174 { }
1175
1176 // Aliasing constructor
1177 template<typename _Yp>
1178 __shared_ptr(__shared_ptr<_Yp, _Lp>&& __r,
1179 element_type* __p) noexcept
1180 : _M_ptr(__p), _M_refcount()
1181 {
1182 _M_refcount._M_swap(__r._M_refcount);
1183 __r._M_ptr = 0;
1184 }
1185
1186 __shared_ptr(const __shared_ptr&) noexcept = default;
1187 __shared_ptr& operator=(const __shared_ptr&) noexcept = default;
1188 ~__shared_ptr() = default;
1189
1190 template<typename _Yp, typename = _Compatible<_Yp>>
1191 __shared_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1192 : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
1193 { }
1194
1195 __shared_ptr(__shared_ptr&& __r) noexcept
1196 : _M_ptr(__r._M_ptr), _M_refcount()
1197 {
1198 _M_refcount._M_swap(__r._M_refcount);
1199 __r._M_ptr = 0;
1200 }
1201
1202 template<typename _Yp, typename = _Compatible<_Yp>>
1203 __shared_ptr(__shared_ptr<_Yp, _Lp>&& __r) noexcept
1204 : _M_ptr(__r._M_ptr), _M_refcount()
1205 {
1206 _M_refcount._M_swap(__r._M_refcount);
1207 __r._M_ptr = 0;
1208 }
1209
1210 template<typename _Yp, typename = _Compatible<_Yp>>
1211 explicit __shared_ptr(const __weak_ptr<_Yp, _Lp>& __r)
1212 : _M_refcount(__r._M_refcount) // may throw
1213 {
1214 // It is now safe to copy __r._M_ptr, as
1215 // _M_refcount(__r._M_refcount) did not throw.
1216 _M_ptr = __r._M_ptr;
1217 }
1218
1219 // If an exception is thrown this constructor has no effect.
1220 template<typename _Yp, typename _Del,
1221 typename = _UniqCompatible<_Yp, _Del>>
1222 __shared_ptr(unique_ptr<_Yp, _Del>&& __r)
1223 : _M_ptr(__r.get()), _M_refcount()
1224 {
1225 auto __raw = __to_address(__r.get());
1226 _M_refcount = __shared_count<_Lp>(std::move(__r));
1227 _M_enable_shared_from_this_with(__raw);
1228 }
1229
1230#if __cplusplus <= 201402L && _GLIBCXX_USE_DEPRECATED
1231 protected:
1232 // If an exception is thrown this constructor has no effect.
1233 template<typename _Tp1, typename _Del,
1234 typename enable_if<__and_<
1235 __not_<is_array<_Tp>>, is_array<_Tp1>,
1236 is_convertible<typename unique_ptr<_Tp1, _Del>::pointer, _Tp*>
1237 >::value, bool>::type = true>
1238 __shared_ptr(unique_ptr<_Tp1, _Del>&& __r, __sp_array_delete)
1239 : _M_ptr(__r.get()), _M_refcount()
1240 {
1241 auto __raw = __to_address(__r.get());
1242 _M_refcount = __shared_count<_Lp>(std::move(__r));
1243 _M_enable_shared_from_this_with(__raw);
1244 }
1245 public:
1246#endif
1247
1248#if _GLIBCXX_USE_DEPRECATED
1249#pragma GCC diagnostic push
1250#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
1251 // Postcondition: use_count() == 1 and __r.get() == 0
1252 template<typename _Yp, typename = _Compatible<_Yp>>
1253 __shared_ptr(auto_ptr<_Yp>&& __r);
1254#pragma GCC diagnostic pop
1255#endif
1256
1257 constexpr __shared_ptr(nullptr_t) noexcept : __shared_ptr() { }
1258
1259 template<typename _Yp>
1260 _Assignable<_Yp>
1261 operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1262 {
1263 _M_ptr = __r._M_ptr;
1264 _M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw
1265 return *this;
1266 }
1267
1268#if _GLIBCXX_USE_DEPRECATED
1269#pragma GCC diagnostic push
1270#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
1271 template<typename _Yp>
1272 _Assignable<_Yp>
1273 operator=(auto_ptr<_Yp>&& __r)
1274 {
1275 __shared_ptr(std::move(__r)).swap(*this);
1276 return *this;
1277 }
1278#pragma GCC diagnostic pop
1279#endif
1280
1281 __shared_ptr&
1282 operator=(__shared_ptr&& __r) noexcept
1283 {
1284 __shared_ptr(std::move(__r)).swap(*this);
1285 return *this;
1286 }
1287
1288 template<class _Yp>
1289 _Assignable<_Yp>
1290 operator=(__shared_ptr<_Yp, _Lp>&& __r) noexcept
1291 {
1292 __shared_ptr(std::move(__r)).swap(*this);
1293 return *this;
1294 }
1295
1296 template<typename _Yp, typename _Del>
1297 _UniqAssignable<_Yp, _Del>
1298 operator=(unique_ptr<_Yp, _Del>&& __r)
1299 {
1300 __shared_ptr(std::move(__r)).swap(*this);
1301 return *this;
1302 }
1303
1304 void
1305 reset() noexcept
1306 { __shared_ptr().swap(*this); }
1307
1308 template<typename _Yp>
1309 _SafeConv<_Yp>
1310 reset(_Yp* __p) // _Yp must be complete.
1311 {
1312 // Catch self-reset errors.
1313 __glibcxx_assert(__p == 0 || __p != _M_ptr);
1314 __shared_ptr(__p).swap(*this);
1315 }
1316
1317 template<typename _Yp, typename _Deleter>
1318 _SafeConv<_Yp>
1319 reset(_Yp* __p, _Deleter __d)
1320 { __shared_ptr(__p, std::move(__d)).swap(*this); }
1321
1322 template<typename _Yp, typename _Deleter, typename _Alloc>
1323 _SafeConv<_Yp>
1324 reset(_Yp* __p, _Deleter __d, _Alloc __a)
1325 { __shared_ptr(__p, std::move(__d), std::move(__a)).swap(*this); }
1326
1327 /// Return the stored pointer.
1328 element_type*
1329 get() const noexcept
1330 { return _M_ptr; }
1331
1332 /// Return true if the stored pointer is not null.
1333 explicit operator bool() const // never throws
1334 { return _M_ptr == 0 ? false : true; }
1335
1336 /// Return true if use_count() == 1.
1337 bool
1338 unique() const noexcept
1339 { return _M_refcount._M_unique(); }
1340
1341 /// If *this owns a pointer, return the number of owners, otherwise zero.
1342 long
1343 use_count() const noexcept
1344 { return _M_refcount._M_get_use_count(); }
1345
1346 /// Exchange both the owned pointer and the stored pointer.
1347 void
1348 swap(__shared_ptr<_Tp, _Lp>& __other) noexcept
1349 {
1350 std::swap(_M_ptr, __other._M_ptr);
1351 _M_refcount._M_swap(__other._M_refcount);
1352 }
1353
1354 /** @brief Define an ordering based on ownership.
1355 *
1356 * This function defines a strict weak ordering between two shared_ptr
1357 * or weak_ptr objects, such that one object is less than the other
1358 * unless they share ownership of the same pointer, or are both empty.
1359 * @{
1360 */
1361 template<typename _Tp1>
1362 bool
1363 owner_before(__shared_ptr<_Tp1, _Lp> const& __rhs) const noexcept
1364 { return _M_refcount._M_less(__rhs._M_refcount); }
1365
1366 template<typename _Tp1>
1367 bool
1368 owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const noexcept
1369 { return _M_refcount._M_less(__rhs._M_refcount); }
1370 /// @}
1371
1372 protected:
1373 // This constructor is non-standard, it is used by allocate_shared.
1374 template<typename _Alloc, typename... _Args>
1375 __shared_ptr(_Sp_alloc_shared_tag<_Alloc> __tag, _Args&&... __args)
1376 : _M_ptr(), _M_refcount(_M_ptr, __tag, std::forward<_Args>(__args)...)
1377 { _M_enable_shared_from_this_with(_M_ptr); }
1378
1379 template<typename _Tp1, _Lock_policy _Lp1, typename _Alloc,
1380 typename... _Args>
1381 friend __shared_ptr<_Tp1, _Lp1>
1382 __allocate_shared(const _Alloc& __a, _Args&&... __args);
1383
1384 // This constructor is used by __weak_ptr::lock() and
1385 // shared_ptr::shared_ptr(const weak_ptr&, std::nothrow_t).
1386 __shared_ptr(const __weak_ptr<_Tp, _Lp>& __r, std::nothrow_t)
1387 : _M_refcount(__r._M_refcount, std::nothrow)
1388 {
1389 _M_ptr = _M_refcount._M_get_use_count() ? __r._M_ptr : nullptr;
1390 }
1391
1392 friend class __weak_ptr<_Tp, _Lp>;
1393
1394 private:
1395
1396 template<typename _Yp>
1397 using __esft_base_t = decltype(__enable_shared_from_this_base(
1398 std::declval<const __shared_count<_Lp>&>(),
1399 std::declval<_Yp*>()));
1400
1401 // Detect an accessible and unambiguous enable_shared_from_this base.
1402 template<typename _Yp, typename = void>
1403 struct __has_esft_base
1404 : false_type { };
1405
1406 template<typename _Yp>
1407 struct __has_esft_base<_Yp, __void_t<__esft_base_t<_Yp>>>
1408 : __not_<is_array<_Tp>> { }; // No enable shared_from_this for arrays
1409
1410 template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type>
1411 typename enable_if<__has_esft_base<_Yp2>::value>::type
1412 _M_enable_shared_from_this_with(_Yp* __p) noexcept
1413 {
1414 if (auto __base = __enable_shared_from_this_base(_M_refcount, __p))
1415 __base->_M_weak_assign(const_cast<_Yp2*>(__p), _M_refcount);
1416 }
1417
1418 template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type>
1419 typename enable_if<!__has_esft_base<_Yp2>::value>::type
1420 _M_enable_shared_from_this_with(_Yp*) noexcept
1421 { }
1422
1423 void*
1424 _M_get_deleter(const std::type_info& __ti) const noexcept
1425 { return _M_refcount._M_get_deleter(__ti); }
1426
1427 template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
1428 template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
1429
1430 template<typename _Del, typename _Tp1, _Lock_policy _Lp1>
1431 friend _Del* get_deleter(const __shared_ptr<_Tp1, _Lp1>&) noexcept;
1432
1433 template<typename _Del, typename _Tp1>
1434 friend _Del* get_deleter(const shared_ptr<_Tp1>&) noexcept;
1435
1436 element_type* _M_ptr; // Contained pointer.
1437 __shared_count<_Lp> _M_refcount; // Reference counter.
1438 };
1439
1440
1441 // 20.7.2.2.7 shared_ptr comparisons
1442 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1443 inline bool
1444 operator==(const __shared_ptr<_Tp1, _Lp>& __a,
1445 const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1446 { return __a.get() == __b.get(); }
1447
1448 template<typename _Tp, _Lock_policy _Lp>
1449 inline bool
1450 operator==(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1451 { return !__a; }
1452
1453#ifdef __cpp_lib_three_way_comparison
1454 template<typename _Tp, typename _Up, _Lock_policy _Lp>
1455 inline strong_ordering
1456 operator<=>(const __shared_ptr<_Tp, _Lp>& __a,
1457 const __shared_ptr<_Up, _Lp>& __b) noexcept
1458 { return compare_three_way()(__a.get(), __b.get()); }
1459
1460 template<typename _Tp, _Lock_policy _Lp>
1461 inline strong_ordering
1462 operator<=>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1463 {
1464 using pointer = typename __shared_ptr<_Tp, _Lp>::element_type*;
1465 return compare_three_way()(__a.get(), static_cast<pointer>(nullptr));
1466 }
1467#else
1468 template<typename _Tp, _Lock_policy _Lp>
1469 inline bool
1470 operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1471 { return !__a; }
1472
1473 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1474 inline bool
1475 operator!=(const __shared_ptr<_Tp1, _Lp>& __a,
1476 const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1477 { return __a.get() != __b.get(); }
1478
1479 template<typename _Tp, _Lock_policy _Lp>
1480 inline bool
1481 operator!=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1482 { return (bool)__a; }
1483
1484 template<typename _Tp, _Lock_policy _Lp>
1485 inline bool
1486 operator!=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1487 { return (bool)__a; }
1488
1489 template<typename _Tp, typename _Up, _Lock_policy _Lp>
1490 inline bool
1491 operator<(const __shared_ptr<_Tp, _Lp>& __a,
1492 const __shared_ptr<_Up, _Lp>& __b) noexcept
1493 {
1494 using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
1495 using _Up_elt = typename __shared_ptr<_Up, _Lp>::element_type;
1496 using _Vp = typename common_type<_Tp_elt*, _Up_elt*>::type;
1497 return less<_Vp>()(__a.get(), __b.get());
1498 }
1499
1500 template<typename _Tp, _Lock_policy _Lp>
1501 inline bool
1502 operator<(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1503 {
1504 using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
1505 return less<_Tp_elt*>()(__a.get(), nullptr);
1506 }
1507
1508 template<typename _Tp, _Lock_policy _Lp>
1509 inline bool
1510 operator<(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1511 {
1512 using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
1513 return less<_Tp_elt*>()(nullptr, __a.get());
1514 }
1515
1516 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1517 inline bool
1518 operator<=(const __shared_ptr<_Tp1, _Lp>& __a,
1519 const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1520 { return !(__b < __a); }
1521
1522 template<typename _Tp, _Lock_policy _Lp>
1523 inline bool
1524 operator<=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1525 { return !(nullptr < __a); }
1526
1527 template<typename _Tp, _Lock_policy _Lp>
1528 inline bool
1529 operator<=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1530 { return !(__a < nullptr); }
1531
1532 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1533 inline bool
1534 operator>(const __shared_ptr<_Tp1, _Lp>& __a,
1535 const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1536 { return (__b < __a); }
1537
1538 template<typename _Tp, _Lock_policy _Lp>
1539 inline bool
1540 operator>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1541 { return nullptr < __a; }
1542
1543 template<typename _Tp, _Lock_policy _Lp>
1544 inline bool
1545 operator>(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1546 { return __a < nullptr; }
1547
1548 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1549 inline bool
1550 operator>=(const __shared_ptr<_Tp1, _Lp>& __a,
1551 const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1552 { return !(__a < __b); }
1553
1554 template<typename _Tp, _Lock_policy _Lp>
1555 inline bool
1556 operator>=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1557 { return !(__a < nullptr); }
1558
1559 template<typename _Tp, _Lock_policy _Lp>
1560 inline bool
1561 operator>=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1562 { return !(nullptr < __a); }
1563#endif // three-way comparison
1564
1565 // 20.7.2.2.8 shared_ptr specialized algorithms.
1566 template<typename _Tp, _Lock_policy _Lp>
1567 inline void
1568 swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b) noexcept
1569 { __a.swap(__b); }
1570
1571 // 20.7.2.2.9 shared_ptr casts
1572
1573 // The seemingly equivalent code:
1574 // shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get()))
1575 // will eventually result in undefined behaviour, attempting to
1576 // delete the same object twice.
1577 /// static_pointer_cast
1578 template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1579 inline __shared_ptr<_Tp, _Lp>
1580 static_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1581 {
1582 using _Sp = __shared_ptr<_Tp, _Lp>;
1583 return _Sp(__r, static_cast<typename _Sp::element_type*>(__r.get()));
1584 }
1585
1586 // The seemingly equivalent code:
1587 // shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get()))
1588 // will eventually result in undefined behaviour, attempting to
1589 // delete the same object twice.
1590 /// const_pointer_cast
1591 template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1592 inline __shared_ptr<_Tp, _Lp>
1593 const_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1594 {
1595 using _Sp = __shared_ptr<_Tp, _Lp>;
1596 return _Sp(__r, const_cast<typename _Sp::element_type*>(__r.get()));
1597 }
1598
1599 // The seemingly equivalent code:
1600 // shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get()))
1601 // will eventually result in undefined behaviour, attempting to
1602 // delete the same object twice.
1603 /// dynamic_pointer_cast
1604 template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1605 inline __shared_ptr<_Tp, _Lp>
1606 dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1607 {
1608 using _Sp = __shared_ptr<_Tp, _Lp>;
1609 if (auto* __p = dynamic_cast<typename _Sp::element_type*>(__r.get()))
1610 return _Sp(__r, __p);
1611 return _Sp();
1612 }
1613
1614#if __cplusplus > 201402L
1615 template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1616 inline __shared_ptr<_Tp, _Lp>
1617 reinterpret_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1618 {
1619 using _Sp = __shared_ptr<_Tp, _Lp>;
1620 return _Sp(__r, reinterpret_cast<typename _Sp::element_type*>(__r.get()));
1621 }
1622#endif
1623
1624 template<typename _Tp, _Lock_policy _Lp>
1625 class __weak_ptr
1626 {
1627 template<typename _Yp, typename _Res = void>
1628 using _Compatible = typename
1629 enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type;
1630
1631 // Constraint for assignment from shared_ptr and weak_ptr:
1632 template<typename _Yp>
1633 using _Assignable = _Compatible<_Yp, __weak_ptr&>;
1634
1635 public:
1636 using element_type = typename remove_extent<_Tp>::type;
1637
1638 constexpr __weak_ptr() noexcept
1639 : _M_ptr(nullptr), _M_refcount()
1640 { }
1641
1642 __weak_ptr(const __weak_ptr&) noexcept = default;
1643
1644 ~__weak_ptr() = default;
1645
1646 // The "obvious" converting constructor implementation:
1647 //
1648 // template<typename _Tp1>
1649 // __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
1650 // : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
1651 // { }
1652 //
1653 // has a serious problem.
1654 //
1655 // __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr)
1656 // conversion may require access to *__r._M_ptr (virtual inheritance).
1657 //
1658 // It is not possible to avoid spurious access violations since
1659 // in multithreaded programs __r._M_ptr may be invalidated at any point.
1660 template<typename _Yp, typename = _Compatible<_Yp>>
1661 __weak_ptr(const __weak_ptr<_Yp, _Lp>& __r) noexcept
1662 : _M_refcount(__r._M_refcount)
1663 { _M_ptr = __r.lock().get(); }
1664
1665 template<typename _Yp, typename = _Compatible<_Yp>>
1666 __weak_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1667 : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
1668 { }
1669
1670 __weak_ptr(__weak_ptr&& __r) noexcept
1671 : _M_ptr(__r._M_ptr), _M_refcount(std::move(__r._M_refcount))
1672 { __r._M_ptr = nullptr; }
1673
1674 template<typename _Yp, typename = _Compatible<_Yp>>
1675 __weak_ptr(__weak_ptr<_Yp, _Lp>&& __r) noexcept
1676 : _M_ptr(__r.lock().get()), _M_refcount(std::move(__r._M_refcount))
1677 { __r._M_ptr = nullptr; }
1678
1679 __weak_ptr&
1680 operator=(const __weak_ptr& __r) noexcept = default;
1681
1682 template<typename _Yp>
1683 _Assignable<_Yp>
1684 operator=(const __weak_ptr<_Yp, _Lp>& __r) noexcept
1685 {
1686 _M_ptr = __r.lock().get();
1687 _M_refcount = __r._M_refcount;
1688 return *this;
1689 }
1690
1691 template<typename _Yp>
1692 _Assignable<_Yp>
1693 operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1694 {
1695 _M_ptr = __r._M_ptr;
1696 _M_refcount = __r._M_refcount;
1697 return *this;
1698 }
1699
1700 __weak_ptr&
1701 operator=(__weak_ptr&& __r) noexcept
1702 {
1703 __weak_ptr(std::move(__r)).swap(*this);
1704 return *this;
1705 }
1706
1707 template<typename _Yp>
1708 _Assignable<_Yp>
1709 operator=(__weak_ptr<_Yp, _Lp>&& __r) noexcept
1710 {
1711 _M_ptr = __r.lock().get();
1712 _M_refcount = std::move(__r._M_refcount);
1713 __r._M_ptr = nullptr;
1714 return *this;
1715 }
1716
1717 __shared_ptr<_Tp, _Lp>
1718 lock() const noexcept
1719 { return __shared_ptr<element_type, _Lp>(*this, std::nothrow); }
1720
1721 long
1722 use_count() const noexcept
1723 { return _M_refcount._M_get_use_count(); }
1724
1725 bool
1726 expired() const noexcept
1727 { return _M_refcount._M_get_use_count() == 0; }
1728
1729 template<typename _Tp1>
1730 bool
1731 owner_before(const __shared_ptr<_Tp1, _Lp>& __rhs) const noexcept
1732 { return _M_refcount._M_less(__rhs._M_refcount); }
1733
1734 template<typename _Tp1>
1735 bool
1736 owner_before(const __weak_ptr<_Tp1, _Lp>& __rhs) const noexcept
1737 { return _M_refcount._M_less(__rhs._M_refcount); }
1738
1739 void
1740 reset() noexcept
1741 { __weak_ptr().swap(*this); }
1742
1743 void
1744 swap(__weak_ptr& __s) noexcept
1745 {
1746 std::swap(_M_ptr, __s._M_ptr);
1747 _M_refcount._M_swap(__s._M_refcount);
1748 }
1749
1750 private:
1751 // Used by __enable_shared_from_this.
1752 void
1753 _M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount) noexcept
1754 {
1755 if (use_count() == 0)
1756 {
1757 _M_ptr = __ptr;
1758 _M_refcount = __refcount;
1759 }
1760 }
1761
1762 template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
1763 template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
1764 friend class __enable_shared_from_this<_Tp, _Lp>;
1765 friend class enable_shared_from_this<_Tp>;
1766
1767 element_type* _M_ptr; // Contained pointer.
1768 __weak_count<_Lp> _M_refcount; // Reference counter.
1769 };
1770
1771 // 20.7.2.3.6 weak_ptr specialized algorithms.
1772 template<typename _Tp, _Lock_policy _Lp>
1773 inline void
1774 swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b) noexcept
1775 { __a.swap(__b); }
1776
1777 template<typename _Tp, typename _Tp1>
1778 struct _Sp_owner_less : public binary_function<_Tp, _Tp, bool>
1779 {
1780 bool
1781 operator()(const _Tp& __lhs, const _Tp& __rhs) const noexcept
1782 { return __lhs.owner_before(__rhs); }
1783
1784 bool
1785 operator()(const _Tp& __lhs, const _Tp1& __rhs) const noexcept
1786 { return __lhs.owner_before(__rhs); }
1787
1788 bool
1789 operator()(const _Tp1& __lhs, const _Tp& __rhs) const noexcept
1790 { return __lhs.owner_before(__rhs); }
1791 };
1792
1793 template<>
1794 struct _Sp_owner_less<void, void>
1795 {
1796 template<typename _Tp, typename _Up>
1797 auto
1798 operator()(const _Tp& __lhs, const _Up& __rhs) const noexcept
1799 -> decltype(__lhs.owner_before(__rhs))
1800 { return __lhs.owner_before(__rhs); }
1801
1802 using is_transparent = void;
1803 };
1804
1805 template<typename _Tp, _Lock_policy _Lp>
1806 struct owner_less<__shared_ptr<_Tp, _Lp>>
1807 : public _Sp_owner_less<__shared_ptr<_Tp, _Lp>, __weak_ptr<_Tp, _Lp>>
1808 { };
1809
1810 template<typename _Tp, _Lock_policy _Lp>
1811 struct owner_less<__weak_ptr<_Tp, _Lp>>
1812 : public _Sp_owner_less<__weak_ptr<_Tp, _Lp>, __shared_ptr<_Tp, _Lp>>
1813 { };
1814
1815
1816 template<typename _Tp, _Lock_policy _Lp>
1817 class __enable_shared_from_this
1818 {
1819 protected:
1820 constexpr __enable_shared_from_this() noexcept { }
1821
1822 __enable_shared_from_this(const __enable_shared_from_this&) noexcept { }
1823
1824 __enable_shared_from_this&
1825 operator=(const __enable_shared_from_this&) noexcept
1826 { return *this; }
1827
1828 ~__enable_shared_from_this() { }
1829
1830 public:
1831 __shared_ptr<_Tp, _Lp>
1832 shared_from_this()
1833 { return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); }
1834
1835 __shared_ptr<const _Tp, _Lp>
1836 shared_from_this() const
1837 { return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); }
1838
1839#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
1840 __weak_ptr<_Tp, _Lp>
1841 weak_from_this() noexcept
1842 { return this->_M_weak_this; }
1843
1844 __weak_ptr<const _Tp, _Lp>
1845 weak_from_this() const noexcept
1846 { return this->_M_weak_this; }
1847#endif
1848
1849 private:
1850 template<typename _Tp1>
1851 void
1852 _M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const noexcept
1853 { _M_weak_this._M_assign(__p, __n); }
1854
1855 friend const __enable_shared_from_this*
1856 __enable_shared_from_this_base(const __shared_count<_Lp>&,
1857 const __enable_shared_from_this* __p)
1858 { return __p; }
1859
1860 template<typename, _Lock_policy>
1861 friend class __shared_ptr;
1862
1863 mutable __weak_ptr<_Tp, _Lp> _M_weak_this;
1864 };
1865
1866 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy,
1867 typename _Alloc, typename... _Args>
1868 inline __shared_ptr<_Tp, _Lp>
1869 __allocate_shared(const _Alloc& __a, _Args&&... __args)
1870 {
1871 static_assert(!is_array<_Tp>::value, "make_shared<T[]> not supported");
1872
1873 return __shared_ptr<_Tp, _Lp>(_Sp_alloc_shared_tag<_Alloc>{__a},
1874 std::forward<_Args>(__args)...);
1875 }
1876
1877 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy,
1878 typename... _Args>
1879 inline __shared_ptr<_Tp, _Lp>
1880 __make_shared(_Args&&... __args)
1881 {
1882 typedef typename std::remove_const<_Tp>::type _Tp_nc;
1883 return std::__allocate_shared<_Tp, _Lp>(std::allocator<_Tp_nc>(),
1884 std::forward<_Args>(__args)...);
1885 }
1886
1887 /// std::hash specialization for __shared_ptr.
1888 template<typename _Tp, _Lock_policy _Lp>
1889 struct hash<__shared_ptr<_Tp, _Lp>>
1890 : public __hash_base<size_t, __shared_ptr<_Tp, _Lp>>
1891 {
1892 size_t
1893 operator()(const __shared_ptr<_Tp, _Lp>& __s) const noexcept
1894 {
1896 __s.get());
1897 }
1898 };
1899
1900_GLIBCXX_END_NAMESPACE_VERSION
1901} // namespace
1902
1903#endif // _SHARED_PTR_BASE_H
constexpr complex< _Tp > operator*(const complex< _Tp > &__x, const complex< _Tp > &__y)
Return new complex value x times y.
Definition: complex:391
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:75
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:78
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:101
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition: move.h:49
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition: move.h:76
void lock(_L1 &__l1, _L2 &__l2, _L3 &... __l3)
Generic lock.
Definition: mutex:589
ISO C++ entities toplevel namespace is std.
__shared_ptr< _Tp, _Lp > dynamic_pointer_cast(const __shared_ptr< _Tp1, _Lp > &__r) noexcept
dynamic_pointer_cast
__shared_ptr< _Tp, _Lp > static_pointer_cast(const __shared_ptr< _Tp1, _Lp > &__r) noexcept
static_pointer_cast
__allocated_ptr< _Alloc > __allocate_guarded(_Alloc &__a)
Allocate space for a single object using __a.
Definition: allocated_ptr.h:95
__shared_ptr< _Tp, _Lp > const_pointer_cast(const __shared_ptr< _Tp1, _Lp > &__r) noexcept
const_pointer_cast
constexpr _Iterator __base(_Iterator __it)
Part of RTTI.
Definition: typeinfo:89
Primary class template hash.
static constexpr auto construct(_Alloc &__a, _Tp *__p, _Args &&... __args) noexcept(noexcept(_S_construct(__a, __p, std::forward< _Args >(__args)...))) -> decltype(_S_construct(__a, __p, std::forward< _Args >(__args)...))
Construct an object of type _Tp
static constexpr void destroy(_Alloc &__a, _Tp *__p) noexcept(noexcept(_S_destroy(__a, __p, 0)))
Destroy an object of type _Tp.
The standard allocator, as per C++03 [20.4.1].
Definition: allocator.h:123
Base class for all library exceptions.
Definition: exception.h:61
Exception possibly thrown by shared_ptr.
virtual char const * what() const noexcept
One of the comparison functors.
Definition: stl_function.h:382
20.7.1.2 unique_ptr for single objects.
Definition: unique_ptr.h:243
A simple smart pointer providing strict ownership semantics.
Definition: auto_ptr.h:90
Scoped lock idiom.
Definition: concurrence.h:229