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1 : // shared_ptr and weak_ptr implementation -*- C++ -*-
2 :
3 : // Copyright (C) 2007-2014 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.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_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 : #ifdef __GXX_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>
93 750 : class shared_ptr : public __shared_ptr<_Tp>
94 : {
95 : public:
96 : /**
97 : * @brief Construct an empty %shared_ptr.
98 : * @post use_count()==0 && get()==0
99 : */
100 188 : constexpr shared_ptr() noexcept
101 188 : : __shared_ptr<_Tp>() { }
102 :
103 339 : shared_ptr(const shared_ptr&) noexcept = default;
104 :
105 : /**
106 : * @brief Construct a %shared_ptr that owns the pointer @a __p.
107 : * @param __p A pointer that is convertible to element_type*.
108 : * @post use_count() == 1 && get() == __p
109 : * @throw std::bad_alloc, in which case @c delete @a __p is called.
110 : */
111 : template<typename _Tp1>
112 118 : explicit shared_ptr(_Tp1* __p)
113 118 : : __shared_ptr<_Tp>(__p) { }
114 :
115 : /**
116 : * @brief Construct a %shared_ptr that owns the pointer @a __p
117 : * and the deleter @a __d.
118 : * @param __p A pointer.
119 : * @param __d A deleter.
120 : * @post use_count() == 1 && get() == __p
121 : * @throw std::bad_alloc, in which case @a __d(__p) is called.
122 : *
123 : * Requirements: _Deleter's copy constructor and destructor must
124 : * not throw
125 : *
126 : * __shared_ptr will release __p by calling __d(__p)
127 : */
128 : template<typename _Tp1, typename _Deleter>
129 25 : shared_ptr(_Tp1* __p, _Deleter __d)
130 25 : : __shared_ptr<_Tp>(__p, __d) { }
131 :
132 : /**
133 : * @brief Construct a %shared_ptr that owns a null pointer
134 : * and the deleter @a __d.
135 : * @param __p A null pointer constant.
136 : * @param __d A deleter.
137 : * @post use_count() == 1 && get() == __p
138 : * @throw std::bad_alloc, in which case @a __d(__p) is called.
139 : *
140 : * Requirements: _Deleter's copy constructor and destructor must
141 : * not throw
142 : *
143 : * The last owner will call __d(__p)
144 : */
145 : template<typename _Deleter>
146 : shared_ptr(nullptr_t __p, _Deleter __d)
147 : : __shared_ptr<_Tp>(__p, __d) { }
148 :
149 : /**
150 : * @brief Construct a %shared_ptr that owns the pointer @a __p
151 : * and the deleter @a __d.
152 : * @param __p A pointer.
153 : * @param __d A deleter.
154 : * @param __a An allocator.
155 : * @post use_count() == 1 && get() == __p
156 : * @throw std::bad_alloc, in which case @a __d(__p) is called.
157 : *
158 : * Requirements: _Deleter's copy constructor and destructor must
159 : * not throw _Alloc's copy constructor and destructor must not
160 : * throw.
161 : *
162 : * __shared_ptr will release __p by calling __d(__p)
163 : */
164 : template<typename _Tp1, typename _Deleter, typename _Alloc>
165 : shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a)
166 : : __shared_ptr<_Tp>(__p, __d, std::move(__a)) { }
167 :
168 : /**
169 : * @brief Construct a %shared_ptr that owns a null pointer
170 : * and the deleter @a __d.
171 : * @param __p A null pointer constant.
172 : * @param __d A deleter.
173 : * @param __a An allocator.
174 : * @post use_count() == 1 && get() == __p
175 : * @throw std::bad_alloc, in which case @a __d(__p) is called.
176 : *
177 : * Requirements: _Deleter's copy constructor and destructor must
178 : * not throw _Alloc's copy constructor and destructor must not
179 : * throw.
180 : *
181 : * The last owner will call __d(__p)
182 : */
183 : template<typename _Deleter, typename _Alloc>
184 : shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
185 : : __shared_ptr<_Tp>(__p, __d, std::move(__a)) { }
186 :
187 : // Aliasing constructor
188 :
189 : /**
190 : * @brief Constructs a %shared_ptr instance that stores @a __p
191 : * and shares ownership with @a __r.
192 : * @param __r A %shared_ptr.
193 : * @param __p A pointer that will remain valid while @a *__r is valid.
194 : * @post get() == __p && use_count() == __r.use_count()
195 : *
196 : * This can be used to construct a @c shared_ptr to a sub-object
197 : * of an object managed by an existing @c shared_ptr.
198 : *
199 : * @code
200 : * shared_ptr< pair<int,int> > pii(new pair<int,int>());
201 : * shared_ptr<int> pi(pii, &pii->first);
202 : * assert(pii.use_count() == 2);
203 : * @endcode
204 : */
205 : template<typename _Tp1>
206 : shared_ptr(const shared_ptr<_Tp1>& __r, _Tp* __p) noexcept
207 : : __shared_ptr<_Tp>(__r, __p) { }
208 :
209 : /**
210 : * @brief If @a __r is empty, constructs an empty %shared_ptr;
211 : * otherwise construct a %shared_ptr that shares ownership
212 : * with @a __r.
213 : * @param __r A %shared_ptr.
214 : * @post get() == __r.get() && use_count() == __r.use_count()
215 : */
216 : template<typename _Tp1, typename = typename
217 : std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>
218 40 : shared_ptr(const shared_ptr<_Tp1>& __r) noexcept
219 40 : : __shared_ptr<_Tp>(__r) { }
220 :
221 : /**
222 : * @brief Move-constructs a %shared_ptr instance from @a __r.
223 : * @param __r A %shared_ptr rvalue.
224 : * @post *this contains the old value of @a __r, @a __r is empty.
225 : */
226 : shared_ptr(shared_ptr&& __r) noexcept
227 : : __shared_ptr<_Tp>(std::move(__r)) { }
228 :
229 : /**
230 : * @brief Move-constructs a %shared_ptr instance from @a __r.
231 : * @param __r A %shared_ptr rvalue.
232 : * @post *this contains the old value of @a __r, @a __r is empty.
233 : */
234 : template<typename _Tp1, typename = typename
235 : std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>
236 : shared_ptr(shared_ptr<_Tp1>&& __r) noexcept
237 : : __shared_ptr<_Tp>(std::move(__r)) { }
238 :
239 : /**
240 : * @brief Constructs a %shared_ptr that shares ownership with @a __r
241 : * and stores a copy of the pointer stored in @a __r.
242 : * @param __r A weak_ptr.
243 : * @post use_count() == __r.use_count()
244 : * @throw bad_weak_ptr when __r.expired(),
245 : * in which case the constructor has no effect.
246 : */
247 : template<typename _Tp1>
248 0 : explicit shared_ptr(const weak_ptr<_Tp1>& __r)
249 0 : : __shared_ptr<_Tp>(__r) { }
250 :
251 : #if _GLIBCXX_USE_DEPRECATED
252 : template<typename _Tp1>
253 : shared_ptr(std::auto_ptr<_Tp1>&& __r);
254 : #endif
255 :
256 : template<typename _Tp1, typename _Del>
257 : shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r)
258 : : __shared_ptr<_Tp>(std::move(__r)) { }
259 :
260 : /**
261 : * @brief Construct an empty %shared_ptr.
262 : * @param __p A null pointer constant.
263 : * @post use_count() == 0 && get() == nullptr
264 : */
265 : constexpr shared_ptr(nullptr_t __p) noexcept
266 : : __shared_ptr<_Tp>(__p) { }
267 :
268 : shared_ptr& operator=(const shared_ptr&) noexcept = default;
269 :
270 : template<typename _Tp1>
271 : shared_ptr&
272 : operator=(const shared_ptr<_Tp1>& __r) noexcept
273 : {
274 : this->__shared_ptr<_Tp>::operator=(__r);
275 : return *this;
276 : }
277 :
278 : #if _GLIBCXX_USE_DEPRECATED
279 : template<typename _Tp1>
280 : shared_ptr&
281 : operator=(std::auto_ptr<_Tp1>&& __r)
282 : {
283 : this->__shared_ptr<_Tp>::operator=(std::move(__r));
284 : return *this;
285 : }
286 : #endif
287 :
288 : shared_ptr&
289 : operator=(shared_ptr&& __r) noexcept
290 : {
291 : this->__shared_ptr<_Tp>::operator=(std::move(__r));
292 : return *this;
293 : }
294 :
295 : template<class _Tp1>
296 : shared_ptr&
297 : operator=(shared_ptr<_Tp1>&& __r) noexcept
298 : {
299 : this->__shared_ptr<_Tp>::operator=(std::move(__r));
300 : return *this;
301 : }
302 :
303 : template<typename _Tp1, typename _Del>
304 : shared_ptr&
305 : operator=(std::unique_ptr<_Tp1, _Del>&& __r)
306 : {
307 : this->__shared_ptr<_Tp>::operator=(std::move(__r));
308 : return *this;
309 : }
310 :
311 : private:
312 : // This constructor is non-standard, it is used by allocate_shared.
313 : template<typename _Alloc, typename... _Args>
314 : shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a,
315 : _Args&&... __args)
316 : : __shared_ptr<_Tp>(__tag, __a, std::forward<_Args>(__args)...)
317 : { }
318 :
319 : template<typename _Tp1, typename _Alloc, typename... _Args>
320 : friend shared_ptr<_Tp1>
321 : allocate_shared(const _Alloc& __a, _Args&&... __args);
322 :
323 : // This constructor is non-standard, it is used by weak_ptr::lock().
324 40 : shared_ptr(const weak_ptr<_Tp>& __r, std::nothrow_t)
325 40 : : __shared_ptr<_Tp>(__r, std::nothrow) { }
326 :
327 : friend class weak_ptr<_Tp>;
328 : };
329 :
330 : // 20.7.2.2.7 shared_ptr comparisons
331 : template<typename _Tp1, typename _Tp2>
332 : inline bool
333 : operator==(const shared_ptr<_Tp1>& __a,
334 : const shared_ptr<_Tp2>& __b) noexcept
335 : { return __a.get() == __b.get(); }
336 :
337 : template<typename _Tp>
338 : inline bool
339 : operator==(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
340 : { return !__a; }
341 :
342 : template<typename _Tp>
343 : inline bool
344 : operator==(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
345 : { return !__a; }
346 :
347 : template<typename _Tp1, typename _Tp2>
348 : inline bool
349 : operator!=(const shared_ptr<_Tp1>& __a,
350 : const shared_ptr<_Tp2>& __b) noexcept
351 : { return __a.get() != __b.get(); }
352 :
353 : template<typename _Tp>
354 : inline bool
355 : operator!=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
356 : { return (bool)__a; }
357 :
358 : template<typename _Tp>
359 : inline bool
360 : operator!=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
361 : { return (bool)__a; }
362 :
363 : template<typename _Tp1, typename _Tp2>
364 : inline bool
365 : operator<(const shared_ptr<_Tp1>& __a,
366 : const shared_ptr<_Tp2>& __b) noexcept
367 : {
368 : typedef typename std::common_type<_Tp1*, _Tp2*>::type _CT;
369 : return std::less<_CT>()(__a.get(), __b.get());
370 : }
371 :
372 : template<typename _Tp>
373 : inline bool
374 : operator<(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
375 : { return std::less<_Tp*>()(__a.get(), nullptr); }
376 :
377 : template<typename _Tp>
378 : inline bool
379 : operator<(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
380 : { return std::less<_Tp*>()(nullptr, __a.get()); }
381 :
382 : template<typename _Tp1, typename _Tp2>
383 : inline bool
384 : operator<=(const shared_ptr<_Tp1>& __a,
385 : const shared_ptr<_Tp2>& __b) noexcept
386 : { return !(__b < __a); }
387 :
388 : template<typename _Tp>
389 : inline bool
390 : operator<=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
391 : { return !(nullptr < __a); }
392 :
393 : template<typename _Tp>
394 : inline bool
395 : operator<=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
396 : { return !(__a < nullptr); }
397 :
398 : template<typename _Tp1, typename _Tp2>
399 : inline bool
400 : operator>(const shared_ptr<_Tp1>& __a,
401 : const shared_ptr<_Tp2>& __b) noexcept
402 : { return (__b < __a); }
403 :
404 : template<typename _Tp>
405 : inline bool
406 : operator>(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
407 : { return std::less<_Tp*>()(nullptr, __a.get()); }
408 :
409 : template<typename _Tp>
410 : inline bool
411 : operator>(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
412 : { return std::less<_Tp*>()(__a.get(), nullptr); }
413 :
414 : template<typename _Tp1, typename _Tp2>
415 : inline bool
416 : operator>=(const shared_ptr<_Tp1>& __a,
417 : const shared_ptr<_Tp2>& __b) noexcept
418 : { return !(__a < __b); }
419 :
420 : template<typename _Tp>
421 : inline bool
422 : operator>=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
423 : { return !(__a < nullptr); }
424 :
425 : template<typename _Tp>
426 : inline bool
427 : operator>=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
428 : { return !(nullptr < __a); }
429 :
430 : template<typename _Tp>
431 : struct less<shared_ptr<_Tp>> : public _Sp_less<shared_ptr<_Tp>>
432 : { };
433 :
434 : // 20.7.2.2.8 shared_ptr specialized algorithms.
435 : template<typename _Tp>
436 : inline void
437 53 : swap(shared_ptr<_Tp>& __a, shared_ptr<_Tp>& __b) noexcept
438 53 : { __a.swap(__b); }
439 :
440 : // 20.7.2.2.9 shared_ptr casts.
441 : template<typename _Tp, typename _Tp1>
442 : inline shared_ptr<_Tp>
443 : static_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept
444 : { return shared_ptr<_Tp>(__r, static_cast<_Tp*>(__r.get())); }
445 :
446 : template<typename _Tp, typename _Tp1>
447 : inline shared_ptr<_Tp>
448 : const_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept
449 : { return shared_ptr<_Tp>(__r, const_cast<_Tp*>(__r.get())); }
450 :
451 : template<typename _Tp, typename _Tp1>
452 : inline shared_ptr<_Tp>
453 : dynamic_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept
454 : {
455 : if (_Tp* __p = dynamic_cast<_Tp*>(__r.get()))
456 : return shared_ptr<_Tp>(__r, __p);
457 : return shared_ptr<_Tp>();
458 : }
459 :
460 :
461 : /**
462 : * @brief A smart pointer with weak semantics.
463 : *
464 : * With forwarding constructors and assignment operators.
465 : */
466 : template<typename _Tp>
467 52 : class weak_ptr : public __weak_ptr<_Tp>
468 : {
469 : public:
470 0 : constexpr weak_ptr() noexcept
471 0 : : __weak_ptr<_Tp>() { }
472 :
473 : template<typename _Tp1, typename = typename
474 : std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>
475 : weak_ptr(const weak_ptr<_Tp1>& __r) noexcept
476 : : __weak_ptr<_Tp>(__r) { }
477 :
478 : template<typename _Tp1, typename = typename
479 : std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>
480 40 : weak_ptr(const shared_ptr<_Tp1>& __r) noexcept
481 40 : : __weak_ptr<_Tp>(__r) { }
482 :
483 : template<typename _Tp1>
484 : weak_ptr&
485 : operator=(const weak_ptr<_Tp1>& __r) noexcept
486 : {
487 : this->__weak_ptr<_Tp>::operator=(__r);
488 : return *this;
489 : }
490 :
491 : template<typename _Tp1>
492 : weak_ptr&
493 : operator=(const shared_ptr<_Tp1>& __r) noexcept
494 : {
495 : this->__weak_ptr<_Tp>::operator=(__r);
496 : return *this;
497 : }
498 :
499 : shared_ptr<_Tp>
500 40 : lock() const noexcept
501 40 : { return shared_ptr<_Tp>(*this, std::nothrow); }
502 : };
503 :
504 : // 20.7.2.3.6 weak_ptr specialized algorithms.
505 : template<typename _Tp>
506 : inline void
507 : swap(weak_ptr<_Tp>& __a, weak_ptr<_Tp>& __b) noexcept
508 : { __a.swap(__b); }
509 :
510 :
511 : /// Primary template owner_less
512 : template<typename _Tp>
513 : struct owner_less;
514 :
515 : /// Partial specialization of owner_less for shared_ptr.
516 : template<typename _Tp>
517 : struct owner_less<shared_ptr<_Tp>>
518 : : public _Sp_owner_less<shared_ptr<_Tp>, weak_ptr<_Tp>>
519 : { };
520 :
521 : /// Partial specialization of owner_less for weak_ptr.
522 : template<typename _Tp>
523 : struct owner_less<weak_ptr<_Tp>>
524 : : public _Sp_owner_less<weak_ptr<_Tp>, shared_ptr<_Tp>>
525 : { };
526 :
527 : /**
528 : * @brief Base class allowing use of member function shared_from_this.
529 : */
530 : template<typename _Tp>
531 : class enable_shared_from_this
532 : {
533 : protected:
534 0 : constexpr enable_shared_from_this() noexcept { }
535 :
536 : enable_shared_from_this(const enable_shared_from_this&) noexcept { }
537 :
538 : enable_shared_from_this&
539 : operator=(const enable_shared_from_this&) noexcept
540 : { return *this; }
541 :
542 0 : ~enable_shared_from_this() { }
543 :
544 : public:
545 : shared_ptr<_Tp>
546 0 : shared_from_this()
547 0 : { return shared_ptr<_Tp>(this->_M_weak_this); }
548 :
549 : shared_ptr<const _Tp>
550 : shared_from_this() const
551 : { return shared_ptr<const _Tp>(this->_M_weak_this); }
552 :
553 : private:
554 : template<typename _Tp1>
555 : void
556 0 : _M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const noexcept
557 0 : { _M_weak_this._M_assign(__p, __n); }
558 :
559 : template<typename _Tp1>
560 : friend void
561 0 : __enable_shared_from_this_helper(const __shared_count<>& __pn,
562 : const enable_shared_from_this* __pe,
563 : const _Tp1* __px) noexcept
564 : {
565 0 : if (__pe != 0)
566 0 : __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn);
567 0 : }
568 :
569 : mutable weak_ptr<_Tp> _M_weak_this;
570 : };
571 :
572 : /**
573 : * @brief Create an object that is owned by a shared_ptr.
574 : * @param __a An allocator.
575 : * @param __args Arguments for the @a _Tp object's constructor.
576 : * @return A shared_ptr that owns the newly created object.
577 : * @throw An exception thrown from @a _Alloc::allocate or from the
578 : * constructor of @a _Tp.
579 : *
580 : * A copy of @a __a will be used to allocate memory for the shared_ptr
581 : * and the new object.
582 : */
583 : template<typename _Tp, typename _Alloc, typename... _Args>
584 : inline shared_ptr<_Tp>
585 : allocate_shared(const _Alloc& __a, _Args&&... __args)
586 : {
587 : return shared_ptr<_Tp>(_Sp_make_shared_tag(), __a,
588 : std::forward<_Args>(__args)...);
589 : }
590 :
591 : /**
592 : * @brief Create an object that is owned by a shared_ptr.
593 : * @param __args Arguments for the @a _Tp object's constructor.
594 : * @return A shared_ptr that owns the newly created object.
595 : * @throw std::bad_alloc, or an exception thrown from the
596 : * constructor of @a _Tp.
597 : */
598 : template<typename _Tp, typename... _Args>
599 : inline shared_ptr<_Tp>
600 : make_shared(_Args&&... __args)
601 : {
602 : typedef typename std::remove_const<_Tp>::type _Tp_nc;
603 : return std::allocate_shared<_Tp>(std::allocator<_Tp_nc>(),
604 : std::forward<_Args>(__args)...);
605 : }
606 :
607 : /// std::hash specialization for shared_ptr.
608 : template<typename _Tp>
609 : struct hash<shared_ptr<_Tp>>
610 : : public __hash_base<size_t, shared_ptr<_Tp>>
611 : {
612 : size_t
613 : operator()(const shared_ptr<_Tp>& __s) const noexcept
614 : { return std::hash<_Tp*>()(__s.get()); }
615 : };
616 :
617 : // @} group pointer_abstractions
618 :
619 : _GLIBCXX_END_NAMESPACE_VERSION
620 : } // namespace
621 :
622 : #endif // _SHARED_PTR_H
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