Line data Source code
1 : // shared_ptr and weak_ptr implementation -*- C++ -*-
2 :
3 : // Copyright (C) 2007-2016 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
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_H
50 : #define _SHARED_PTR_H 1
51 :
52 : #include <bits/shared_ptr_base.h>
53 :
54 : namespace std _GLIBCXX_VISIBILITY(default)
55 : {
56 : _GLIBCXX_BEGIN_NAMESPACE_VERSION
57 :
58 : /**
59 : * @addtogroup pointer_abstractions
60 : * @{
61 : */
62 :
63 : /// 20.7.2.2.11 shared_ptr I/O
64 : template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy _Lp>
65 : inline std::basic_ostream<_Ch, _Tr>&
66 : operator<<(std::basic_ostream<_Ch, _Tr>& __os,
67 : const __shared_ptr<_Tp, _Lp>& __p)
68 : {
69 : __os << __p.get();
70 : return __os;
71 : }
72 :
73 : /// 20.7.2.2.10 shared_ptr get_deleter
74 : template<typename _Del, typename _Tp, _Lock_policy _Lp>
75 : inline _Del*
76 : get_deleter(const __shared_ptr<_Tp, _Lp>& __p) noexcept
77 : {
78 : #if __cpp_rtti
79 : return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del)));
80 : #else
81 : return 0;
82 : #endif
83 : }
84 :
85 :
86 : /**
87 : * @brief A smart pointer with reference-counted copy semantics.
88 : *
89 : * The object pointed to is deleted when the last shared_ptr pointing to
90 : * it is destroyed or reset.
91 : */
92 : template<typename _Tp>
93 37424 : class shared_ptr : public __shared_ptr<_Tp>
94 : {
95 : template<typename _Ptr>
96 : using _Convertible
97 : = typename enable_if<is_convertible<_Ptr, _Tp*>::value>::type;
98 :
99 : public:
100 : /**
101 : * @brief Construct an empty %shared_ptr.
102 : * @post use_count()==0 && get()==0
103 : */
104 3085 : constexpr shared_ptr() noexcept
105 3085 : : __shared_ptr<_Tp>() { }
106 :
107 3533 : shared_ptr(const shared_ptr&) noexcept = default;
108 :
109 : /**
110 : * @brief Construct a %shared_ptr that owns the pointer @a __p.
111 : * @param __p A pointer that is convertible to element_type*.
112 : * @post use_count() == 1 && get() == __p
113 : * @throw std::bad_alloc, in which case @c delete @a __p is called.
114 : */
115 : template<typename _Tp1>
116 2195 : explicit shared_ptr(_Tp1* __p)
117 2195 : : __shared_ptr<_Tp>(__p) { }
118 :
119 : /**
120 : * @brief Construct a %shared_ptr that owns the pointer @a __p
121 : * and the deleter @a __d.
122 : * @param __p A pointer.
123 : * @param __d A deleter.
124 : * @post use_count() == 1 && get() == __p
125 : * @throw std::bad_alloc, in which case @a __d(__p) is called.
126 : *
127 : * Requirements: _Deleter's copy constructor and destructor must
128 : * not throw
129 : *
130 : * __shared_ptr will release __p by calling __d(__p)
131 : */
132 : template<typename _Tp1, typename _Deleter>
133 194 : shared_ptr(_Tp1* __p, _Deleter __d)
134 194 : : __shared_ptr<_Tp>(__p, __d) { }
135 :
136 : /**
137 : * @brief Construct a %shared_ptr that owns a null pointer
138 : * and the deleter @a __d.
139 : * @param __p A null pointer constant.
140 : * @param __d A deleter.
141 : * @post use_count() == 1 && get() == __p
142 : * @throw std::bad_alloc, in which case @a __d(__p) is called.
143 : *
144 : * Requirements: _Deleter's copy constructor and destructor must
145 : * not throw
146 : *
147 : * The last owner will call __d(__p)
148 : */
149 : template<typename _Deleter>
150 : shared_ptr(nullptr_t __p, _Deleter __d)
151 : : __shared_ptr<_Tp>(__p, __d) { }
152 :
153 : /**
154 : * @brief Construct a %shared_ptr that owns the pointer @a __p
155 : * and the deleter @a __d.
156 : * @param __p A pointer.
157 : * @param __d A deleter.
158 : * @param __a An allocator.
159 : * @post use_count() == 1 && get() == __p
160 : * @throw std::bad_alloc, in which case @a __d(__p) is called.
161 : *
162 : * Requirements: _Deleter's copy constructor and destructor must
163 : * not throw _Alloc's copy constructor and destructor must not
164 : * throw.
165 : *
166 : * __shared_ptr will release __p by calling __d(__p)
167 : */
168 : template<typename _Tp1, typename _Deleter, typename _Alloc>
169 : shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a)
170 : : __shared_ptr<_Tp>(__p, __d, std::move(__a)) { }
171 :
172 : /**
173 : * @brief Construct a %shared_ptr that owns a null pointer
174 : * and the deleter @a __d.
175 : * @param __p A null pointer constant.
176 : * @param __d A deleter.
177 : * @param __a An allocator.
178 : * @post use_count() == 1 && get() == __p
179 : * @throw std::bad_alloc, in which case @a __d(__p) is called.
180 : *
181 : * Requirements: _Deleter's copy constructor and destructor must
182 : * not throw _Alloc's copy constructor and destructor must not
183 : * throw.
184 : *
185 : * The last owner will call __d(__p)
186 : */
187 : template<typename _Deleter, typename _Alloc>
188 : shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
189 : : __shared_ptr<_Tp>(__p, __d, std::move(__a)) { }
190 :
191 : // Aliasing constructor
192 :
193 : /**
194 : * @brief Constructs a %shared_ptr instance that stores @a __p
195 : * and shares ownership with @a __r.
196 : * @param __r A %shared_ptr.
197 : * @param __p A pointer that will remain valid while @a *__r is valid.
198 : * @post get() == __p && use_count() == __r.use_count()
199 : *
200 : * This can be used to construct a @c shared_ptr to a sub-object
201 : * of an object managed by an existing @c shared_ptr.
202 : *
203 : * @code
204 : * shared_ptr< pair<int,int> > pii(new pair<int,int>());
205 : * shared_ptr<int> pi(pii, &pii->first);
206 : * assert(pii.use_count() == 2);
207 : * @endcode
208 : */
209 : template<typename _Tp1>
210 : shared_ptr(const shared_ptr<_Tp1>& __r, _Tp* __p) noexcept
211 : : __shared_ptr<_Tp>(__r, __p) { }
212 :
213 : /**
214 : * @brief If @a __r is empty, constructs an empty %shared_ptr;
215 : * otherwise construct a %shared_ptr that shares ownership
216 : * with @a __r.
217 : * @param __r A %shared_ptr.
218 : * @post get() == __r.get() && use_count() == __r.use_count()
219 : */
220 : template<typename _Tp1, typename = _Convertible<_Tp1*>>
221 42 : shared_ptr(const shared_ptr<_Tp1>& __r) noexcept
222 42 : : __shared_ptr<_Tp>(__r) { }
223 :
224 : /**
225 : * @brief Move-constructs a %shared_ptr instance from @a __r.
226 : * @param __r A %shared_ptr rvalue.
227 : * @post *this contains the old value of @a __r, @a __r is empty.
228 : */
229 : shared_ptr(shared_ptr&& __r) noexcept
230 : : __shared_ptr<_Tp>(std::move(__r)) { }
231 :
232 : /**
233 : * @brief Move-constructs a %shared_ptr instance from @a __r.
234 : * @param __r A %shared_ptr rvalue.
235 : * @post *this contains the old value of @a __r, @a __r is empty.
236 : */
237 : template<typename _Tp1, typename = _Convertible<_Tp1*>>
238 : shared_ptr(shared_ptr<_Tp1>&& __r) noexcept
239 : : __shared_ptr<_Tp>(std::move(__r)) { }
240 :
241 : /**
242 : * @brief Constructs a %shared_ptr that shares ownership with @a __r
243 : * and stores a copy of the pointer stored in @a __r.
244 : * @param __r A weak_ptr.
245 : * @post use_count() == __r.use_count()
246 : * @throw bad_weak_ptr when __r.expired(),
247 : * in which case the constructor has no effect.
248 : */
249 : template<typename _Tp1>
250 567 : explicit shared_ptr(const weak_ptr<_Tp1>& __r)
251 567 : : __shared_ptr<_Tp>(__r) { }
252 :
253 : #if _GLIBCXX_USE_DEPRECATED
254 : template<typename _Tp1>
255 : shared_ptr(std::auto_ptr<_Tp1>&& __r);
256 : #endif
257 :
258 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
259 : // 2399. shared_ptr's constructor from unique_ptr should be constrained
260 : template<typename _Tp1, typename _Del, typename
261 : = _Convertible<typename unique_ptr<_Tp1, _Del>::pointer>>
262 : shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r)
263 : : __shared_ptr<_Tp>(std::move(__r)) { }
264 :
265 : /**
266 : * @brief Construct an empty %shared_ptr.
267 : * @post use_count() == 0 && get() == nullptr
268 : */
269 : constexpr shared_ptr(nullptr_t) noexcept : shared_ptr() { }
270 :
271 : shared_ptr& operator=(const shared_ptr&) noexcept = default;
272 :
273 : template<typename _Tp1>
274 : shared_ptr&
275 : operator=(const shared_ptr<_Tp1>& __r) noexcept
276 : {
277 : this->__shared_ptr<_Tp>::operator=(__r);
278 : return *this;
279 : }
280 :
281 : #if _GLIBCXX_USE_DEPRECATED
282 : template<typename _Tp1>
283 : shared_ptr&
284 : operator=(std::auto_ptr<_Tp1>&& __r)
285 : {
286 : this->__shared_ptr<_Tp>::operator=(std::move(__r));
287 : return *this;
288 : }
289 : #endif
290 :
291 : shared_ptr&
292 : operator=(shared_ptr&& __r) noexcept
293 : {
294 : this->__shared_ptr<_Tp>::operator=(std::move(__r));
295 : return *this;
296 : }
297 :
298 : template<class _Tp1>
299 : shared_ptr&
300 : operator=(shared_ptr<_Tp1>&& __r) noexcept
301 : {
302 : this->__shared_ptr<_Tp>::operator=(std::move(__r));
303 : return *this;
304 : }
305 :
306 : template<typename _Tp1, typename _Del>
307 : shared_ptr&
308 : operator=(std::unique_ptr<_Tp1, _Del>&& __r)
309 : {
310 : this->__shared_ptr<_Tp>::operator=(std::move(__r));
311 : return *this;
312 : }
313 :
314 : private:
315 : // This constructor is non-standard, it is used by allocate_shared.
316 : template<typename _Alloc, typename... _Args>
317 : shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a,
318 : _Args&&... __args)
319 : : __shared_ptr<_Tp>(__tag, __a, std::forward<_Args>(__args)...)
320 : { }
321 :
322 : template<typename _Tp1, typename _Alloc, typename... _Args>
323 : friend shared_ptr<_Tp1>
324 : allocate_shared(const _Alloc& __a, _Args&&... __args);
325 :
326 : // This constructor is non-standard, it is used by weak_ptr::lock().
327 25062 : shared_ptr(const weak_ptr<_Tp>& __r, std::nothrow_t)
328 25062 : : __shared_ptr<_Tp>(__r, std::nothrow) { }
329 :
330 : friend class weak_ptr<_Tp>;
331 : };
332 :
333 : // 20.7.2.2.7 shared_ptr comparisons
334 : template<typename _Tp1, typename _Tp2>
335 : inline bool
336 : operator==(const shared_ptr<_Tp1>& __a,
337 : const shared_ptr<_Tp2>& __b) noexcept
338 : { return __a.get() == __b.get(); }
339 :
340 : template<typename _Tp>
341 : inline bool
342 : operator==(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
343 : { return !__a; }
344 :
345 : template<typename _Tp>
346 : inline bool
347 : operator==(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
348 : { return !__a; }
349 :
350 : template<typename _Tp1, typename _Tp2>
351 : inline bool
352 : operator!=(const shared_ptr<_Tp1>& __a,
353 : const shared_ptr<_Tp2>& __b) noexcept
354 : { return __a.get() != __b.get(); }
355 :
356 : template<typename _Tp>
357 : inline bool
358 : operator!=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
359 : { return (bool)__a; }
360 :
361 : template<typename _Tp>
362 : inline bool
363 : operator!=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
364 : { return (bool)__a; }
365 :
366 : template<typename _Tp1, typename _Tp2>
367 : inline bool
368 : operator<(const shared_ptr<_Tp1>& __a,
369 : const shared_ptr<_Tp2>& __b) noexcept
370 : {
371 : typedef typename std::common_type<_Tp1*, _Tp2*>::type _CT;
372 : return std::less<_CT>()(__a.get(), __b.get());
373 : }
374 :
375 : template<typename _Tp>
376 : inline bool
377 : operator<(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
378 : { return std::less<_Tp*>()(__a.get(), nullptr); }
379 :
380 : template<typename _Tp>
381 : inline bool
382 : operator<(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
383 : { return std::less<_Tp*>()(nullptr, __a.get()); }
384 :
385 : template<typename _Tp1, typename _Tp2>
386 : inline bool
387 : operator<=(const shared_ptr<_Tp1>& __a,
388 : const shared_ptr<_Tp2>& __b) noexcept
389 : { return !(__b < __a); }
390 :
391 : template<typename _Tp>
392 : inline bool
393 : operator<=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
394 : { return !(nullptr < __a); }
395 :
396 : template<typename _Tp>
397 : inline bool
398 : operator<=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
399 : { return !(__a < nullptr); }
400 :
401 : template<typename _Tp1, typename _Tp2>
402 : inline bool
403 : operator>(const shared_ptr<_Tp1>& __a,
404 : const shared_ptr<_Tp2>& __b) noexcept
405 : { return (__b < __a); }
406 :
407 : template<typename _Tp>
408 : inline bool
409 : operator>(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
410 : { return std::less<_Tp*>()(nullptr, __a.get()); }
411 :
412 : template<typename _Tp>
413 : inline bool
414 : operator>(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
415 : { return std::less<_Tp*>()(__a.get(), nullptr); }
416 :
417 : template<typename _Tp1, typename _Tp2>
418 : inline bool
419 : operator>=(const shared_ptr<_Tp1>& __a,
420 : const shared_ptr<_Tp2>& __b) noexcept
421 : { return !(__a < __b); }
422 :
423 : template<typename _Tp>
424 : inline bool
425 : operator>=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
426 : { return !(__a < nullptr); }
427 :
428 : template<typename _Tp>
429 : inline bool
430 : operator>=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
431 : { return !(nullptr < __a); }
432 :
433 : template<typename _Tp>
434 : struct less<shared_ptr<_Tp>> : public _Sp_less<shared_ptr<_Tp>>
435 : { };
436 :
437 : // 20.7.2.2.8 shared_ptr specialized algorithms.
438 : template<typename _Tp>
439 : inline void
440 194 : swap(shared_ptr<_Tp>& __a, shared_ptr<_Tp>& __b) noexcept
441 194 : { __a.swap(__b); }
442 :
443 : // 20.7.2.2.9 shared_ptr casts.
444 : template<typename _Tp, typename _Tp1>
445 : inline shared_ptr<_Tp>
446 : static_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept
447 : { return shared_ptr<_Tp>(__r, static_cast<_Tp*>(__r.get())); }
448 :
449 : template<typename _Tp, typename _Tp1>
450 : inline shared_ptr<_Tp>
451 : const_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept
452 : { return shared_ptr<_Tp>(__r, const_cast<_Tp*>(__r.get())); }
453 :
454 : template<typename _Tp, typename _Tp1>
455 : inline shared_ptr<_Tp>
456 : dynamic_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept
457 : {
458 : if (_Tp* __p = dynamic_cast<_Tp*>(__r.get()))
459 : return shared_ptr<_Tp>(__r, __p);
460 : return shared_ptr<_Tp>();
461 : }
462 :
463 :
464 : /**
465 : * @brief A smart pointer with weak semantics.
466 : *
467 : * With forwarding constructors and assignment operators.
468 : */
469 : template<typename _Tp>
470 48953 : class weak_ptr : public __weak_ptr<_Tp>
471 : {
472 : template<typename _Ptr>
473 : using _Convertible
474 : = typename enable_if<is_convertible<_Ptr, _Tp*>::value>::type;
475 :
476 : public:
477 126 : constexpr weak_ptr() noexcept = default;
478 :
479 : template<typename _Tp1, typename = _Convertible<_Tp1*>>
480 32559 : weak_ptr(const shared_ptr<_Tp1>& __r) noexcept
481 32559 : : __weak_ptr<_Tp>(__r) { }
482 :
483 16508 : weak_ptr(const weak_ptr&) noexcept = default;
484 :
485 : template<typename _Tp1, typename = _Convertible<_Tp1*>>
486 : weak_ptr(const weak_ptr<_Tp1>& __r) noexcept
487 : : __weak_ptr<_Tp>(__r) { }
488 :
489 4 : weak_ptr(weak_ptr&&) noexcept = default;
490 :
491 : template<typename _Tp1, typename = _Convertible<_Tp1*>>
492 : weak_ptr(weak_ptr<_Tp1>&& __r) noexcept
493 : : __weak_ptr<_Tp>(std::move(__r)) { }
494 :
495 : weak_ptr&
496 : operator=(const weak_ptr& __r) noexcept = default;
497 :
498 : template<typename _Tp1>
499 : weak_ptr&
500 : operator=(const weak_ptr<_Tp1>& __r) noexcept
501 : {
502 : this->__weak_ptr<_Tp>::operator=(__r);
503 : return *this;
504 : }
505 :
506 : template<typename _Tp1>
507 : weak_ptr&
508 : operator=(const shared_ptr<_Tp1>& __r) noexcept
509 : {
510 : this->__weak_ptr<_Tp>::operator=(__r);
511 : return *this;
512 : }
513 :
514 : weak_ptr&
515 : operator=(weak_ptr&& __r) noexcept = default;
516 :
517 : template<typename _Tp1>
518 : weak_ptr&
519 : operator=(weak_ptr<_Tp1>&& __r) noexcept
520 : {
521 : this->__weak_ptr<_Tp>::operator=(std::move(__r));
522 : return *this;
523 : }
524 :
525 : shared_ptr<_Tp>
526 25062 : lock() const noexcept
527 25062 : { return shared_ptr<_Tp>(*this, std::nothrow); }
528 : };
529 :
530 : // 20.7.2.3.6 weak_ptr specialized algorithms.
531 : template<typename _Tp>
532 : inline void
533 : swap(weak_ptr<_Tp>& __a, weak_ptr<_Tp>& __b) noexcept
534 : { __a.swap(__b); }
535 :
536 :
537 : /// Primary template owner_less
538 : template<typename _Tp>
539 : struct owner_less;
540 :
541 : /// Partial specialization of owner_less for shared_ptr.
542 : template<typename _Tp>
543 : struct owner_less<shared_ptr<_Tp>>
544 : : public _Sp_owner_less<shared_ptr<_Tp>, weak_ptr<_Tp>>
545 : { };
546 :
547 : /// Partial specialization of owner_less for weak_ptr.
548 : template<typename _Tp>
549 : struct owner_less<weak_ptr<_Tp>>
550 : : public _Sp_owner_less<weak_ptr<_Tp>, shared_ptr<_Tp>>
551 : { };
552 :
553 : /**
554 : * @brief Base class allowing use of member function shared_from_this.
555 : */
556 : template<typename _Tp>
557 : class enable_shared_from_this
558 : {
559 : protected:
560 126 : constexpr enable_shared_from_this() noexcept { }
561 :
562 : enable_shared_from_this(const enable_shared_from_this&) noexcept { }
563 :
564 : enable_shared_from_this&
565 : operator=(const enable_shared_from_this&) noexcept
566 : { return *this; }
567 :
568 120 : ~enable_shared_from_this() { }
569 :
570 : public:
571 : shared_ptr<_Tp>
572 567 : shared_from_this()
573 567 : { return shared_ptr<_Tp>(this->_M_weak_this); }
574 :
575 : shared_ptr<const _Tp>
576 : shared_from_this() const
577 : { return shared_ptr<const _Tp>(this->_M_weak_this); }
578 :
579 : private:
580 : template<typename _Tp1>
581 : void
582 126 : _M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const noexcept
583 126 : { _M_weak_this._M_assign(__p, __n); }
584 :
585 : template<typename _Tp1, typename _Tp2>
586 : friend void
587 : __enable_shared_from_this_helper(const __shared_count<>&,
588 : const enable_shared_from_this<_Tp1>*,
589 : const _Tp2*) noexcept;
590 :
591 : mutable weak_ptr<_Tp> _M_weak_this;
592 : };
593 :
594 : template<typename _Tp1, typename _Tp2>
595 : inline void
596 126 : __enable_shared_from_this_helper(const __shared_count<>& __pn,
597 : const enable_shared_from_this<_Tp1>*
598 : __pe, const _Tp2* __px) noexcept
599 : {
600 126 : if (__pe != nullptr)
601 126 : __pe->_M_weak_assign(const_cast<_Tp2*>(__px), __pn);
602 126 : }
603 :
604 : /**
605 : * @brief Create an object that is owned by a shared_ptr.
606 : * @param __a An allocator.
607 : * @param __args Arguments for the @a _Tp object's constructor.
608 : * @return A shared_ptr that owns the newly created object.
609 : * @throw An exception thrown from @a _Alloc::allocate or from the
610 : * constructor of @a _Tp.
611 : *
612 : * A copy of @a __a will be used to allocate memory for the shared_ptr
613 : * and the new object.
614 : */
615 : template<typename _Tp, typename _Alloc, typename... _Args>
616 : inline shared_ptr<_Tp>
617 : allocate_shared(const _Alloc& __a, _Args&&... __args)
618 : {
619 : return shared_ptr<_Tp>(_Sp_make_shared_tag(), __a,
620 : std::forward<_Args>(__args)...);
621 : }
622 :
623 : /**
624 : * @brief Create an object that is owned by a shared_ptr.
625 : * @param __args Arguments for the @a _Tp object's constructor.
626 : * @return A shared_ptr that owns the newly created object.
627 : * @throw std::bad_alloc, or an exception thrown from the
628 : * constructor of @a _Tp.
629 : */
630 : template<typename _Tp, typename... _Args>
631 : inline shared_ptr<_Tp>
632 : make_shared(_Args&&... __args)
633 : {
634 : typedef typename std::remove_const<_Tp>::type _Tp_nc;
635 : return std::allocate_shared<_Tp>(std::allocator<_Tp_nc>(),
636 : std::forward<_Args>(__args)...);
637 : }
638 :
639 : /// std::hash specialization for shared_ptr.
640 : template<typename _Tp>
641 : struct hash<shared_ptr<_Tp>>
642 : : public __hash_base<size_t, shared_ptr<_Tp>>
643 : {
644 : size_t
645 : operator()(const shared_ptr<_Tp>& __s) const noexcept
646 : { return std::hash<_Tp*>()(__s.get()); }
647 : };
648 :
649 : // @} group pointer_abstractions
650 :
651 : _GLIBCXX_END_NAMESPACE_VERSION
652 : } // namespace
653 :
654 : #endif // _SHARED_PTR_H
|
