xref: /llvm-project-15.0.7/libcxx/include/atomic (revision d64394b8)
1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_ATOMIC
11#define _LIBCPP_ATOMIC
12
13/*
14    atomic synopsis
15
16namespace std
17{
18
19// feature test macro [version.syn]
20
21#define __cpp_lib_atomic_is_always_lock_free
22#define __cpp_lib_atomic_flag_test
23#define __cpp_lib_atomic_lock_free_type_aliases
24#define __cpp_lib_atomic_wait
25
26 // order and consistency
27
28 enum memory_order: unspecified // enum class in C++20
29 {
30    relaxed,
31    consume, // load-consume
32    acquire, // load-acquire
33    release, // store-release
34    acq_rel, // store-release load-acquire
35    seq_cst // store-release load-acquire
36 };
37
38 inline constexpr auto memory_order_relaxed = memory_order::relaxed;
39 inline constexpr auto memory_order_consume = memory_order::consume;
40 inline constexpr auto memory_order_acquire = memory_order::acquire;
41 inline constexpr auto memory_order_release = memory_order::release;
42 inline constexpr auto memory_order_acq_rel = memory_order::acq_rel;
43 inline constexpr auto memory_order_seq_cst = memory_order::seq_cst;
44
45template <class T> T kill_dependency(T y) noexcept;
46
47// lock-free property
48
49#define ATOMIC_BOOL_LOCK_FREE unspecified
50#define ATOMIC_CHAR_LOCK_FREE unspecified
51#define ATOMIC_CHAR8_T_LOCK_FREE unspecified // C++20
52#define ATOMIC_CHAR16_T_LOCK_FREE unspecified
53#define ATOMIC_CHAR32_T_LOCK_FREE unspecified
54#define ATOMIC_WCHAR_T_LOCK_FREE unspecified
55#define ATOMIC_SHORT_LOCK_FREE unspecified
56#define ATOMIC_INT_LOCK_FREE unspecified
57#define ATOMIC_LONG_LOCK_FREE unspecified
58#define ATOMIC_LLONG_LOCK_FREE unspecified
59#define ATOMIC_POINTER_LOCK_FREE unspecified
60
61template <class T>
62struct atomic
63{
64    using value_type = T;
65
66    static constexpr bool is_always_lock_free;
67    bool is_lock_free() const volatile noexcept;
68    bool is_lock_free() const noexcept;
69
70    atomic() noexcept = default; // until C++20
71    constexpr atomic() noexcept(is_nothrow_default_constructible_v<T>); // since C++20
72    constexpr atomic(T desr) noexcept;
73    atomic(const atomic&) = delete;
74    atomic& operator=(const atomic&) = delete;
75    atomic& operator=(const atomic&) volatile = delete;
76
77    T load(memory_order m = memory_order_seq_cst) const volatile noexcept;
78    T load(memory_order m = memory_order_seq_cst) const noexcept;
79    operator T() const volatile noexcept;
80    operator T() const noexcept;
81    void store(T desr, memory_order m = memory_order_seq_cst) volatile noexcept;
82    void store(T desr, memory_order m = memory_order_seq_cst) noexcept;
83    T operator=(T) volatile noexcept;
84    T operator=(T) noexcept;
85
86    T exchange(T desr, memory_order m = memory_order_seq_cst) volatile noexcept;
87    T exchange(T desr, memory_order m = memory_order_seq_cst) noexcept;
88    bool compare_exchange_weak(T& expc, T desr,
89                               memory_order s, memory_order f) volatile noexcept;
90    bool compare_exchange_weak(T& expc, T desr, memory_order s, memory_order f) noexcept;
91    bool compare_exchange_strong(T& expc, T desr,
92                                 memory_order s, memory_order f) volatile noexcept;
93    bool compare_exchange_strong(T& expc, T desr,
94                                 memory_order s, memory_order f) noexcept;
95    bool compare_exchange_weak(T& expc, T desr,
96                               memory_order m = memory_order_seq_cst) volatile noexcept;
97    bool compare_exchange_weak(T& expc, T desr,
98                               memory_order m = memory_order_seq_cst) noexcept;
99    bool compare_exchange_strong(T& expc, T desr,
100                                memory_order m = memory_order_seq_cst) volatile noexcept;
101    bool compare_exchange_strong(T& expc, T desr,
102                                 memory_order m = memory_order_seq_cst) noexcept;
103
104    void wait(T, memory_order = memory_order::seq_cst) const volatile noexcept;
105    void wait(T, memory_order = memory_order::seq_cst) const noexcept;
106    void notify_one() volatile noexcept;
107    void notify_one() noexcept;
108    void notify_all() volatile noexcept;
109    void notify_all() noexcept;
110};
111
112template <>
113struct atomic<integral>
114{
115    using value_type = integral;
116    using difference_type = value_type;
117
118    static constexpr bool is_always_lock_free;
119    bool is_lock_free() const volatile noexcept;
120    bool is_lock_free() const noexcept;
121
122    atomic() noexcept = default;
123    constexpr atomic(integral desr) noexcept;
124    atomic(const atomic&) = delete;
125    atomic& operator=(const atomic&) = delete;
126    atomic& operator=(const atomic&) volatile = delete;
127
128    integral load(memory_order m = memory_order_seq_cst) const volatile noexcept;
129    integral load(memory_order m = memory_order_seq_cst) const noexcept;
130    operator integral() const volatile noexcept;
131    operator integral() const noexcept;
132    void store(integral desr, memory_order m = memory_order_seq_cst) volatile noexcept;
133    void store(integral desr, memory_order m = memory_order_seq_cst) noexcept;
134    integral operator=(integral desr) volatile noexcept;
135    integral operator=(integral desr) noexcept;
136
137    integral exchange(integral desr,
138                      memory_order m = memory_order_seq_cst) volatile noexcept;
139    integral exchange(integral desr, memory_order m = memory_order_seq_cst) noexcept;
140    bool compare_exchange_weak(integral& expc, integral desr,
141                               memory_order s, memory_order f) volatile noexcept;
142    bool compare_exchange_weak(integral& expc, integral desr,
143                               memory_order s, memory_order f) noexcept;
144    bool compare_exchange_strong(integral& expc, integral desr,
145                                 memory_order s, memory_order f) volatile noexcept;
146    bool compare_exchange_strong(integral& expc, integral desr,
147                                 memory_order s, memory_order f) noexcept;
148    bool compare_exchange_weak(integral& expc, integral desr,
149                               memory_order m = memory_order_seq_cst) volatile noexcept;
150    bool compare_exchange_weak(integral& expc, integral desr,
151                               memory_order m = memory_order_seq_cst) noexcept;
152    bool compare_exchange_strong(integral& expc, integral desr,
153                                memory_order m = memory_order_seq_cst) volatile noexcept;
154    bool compare_exchange_strong(integral& expc, integral desr,
155                                 memory_order m = memory_order_seq_cst) noexcept;
156
157    integral fetch_add(integral op, memory_order m = memory_order_seq_cst) volatile noexcept;
158    integral fetch_add(integral op, memory_order m = memory_order_seq_cst) noexcept;
159    integral fetch_sub(integral op, memory_order m = memory_order_seq_cst) volatile noexcept;
160    integral fetch_sub(integral op, memory_order m = memory_order_seq_cst) noexcept;
161    integral fetch_and(integral op, memory_order m = memory_order_seq_cst) volatile noexcept;
162    integral fetch_and(integral op, memory_order m = memory_order_seq_cst) noexcept;
163    integral fetch_or(integral op, memory_order m = memory_order_seq_cst) volatile noexcept;
164    integral fetch_or(integral op, memory_order m = memory_order_seq_cst) noexcept;
165    integral fetch_xor(integral op, memory_order m = memory_order_seq_cst) volatile noexcept;
166    integral fetch_xor(integral op, memory_order m = memory_order_seq_cst) noexcept;
167
168    integral operator++(int) volatile noexcept;
169    integral operator++(int) noexcept;
170    integral operator--(int) volatile noexcept;
171    integral operator--(int) noexcept;
172    integral operator++() volatile noexcept;
173    integral operator++() noexcept;
174    integral operator--() volatile noexcept;
175    integral operator--() noexcept;
176    integral operator+=(integral op) volatile noexcept;
177    integral operator+=(integral op) noexcept;
178    integral operator-=(integral op) volatile noexcept;
179    integral operator-=(integral op) noexcept;
180    integral operator&=(integral op) volatile noexcept;
181    integral operator&=(integral op) noexcept;
182    integral operator|=(integral op) volatile noexcept;
183    integral operator|=(integral op) noexcept;
184    integral operator^=(integral op) volatile noexcept;
185    integral operator^=(integral op) noexcept;
186
187    void wait(integral, memory_order = memory_order::seq_cst) const volatile noexcept;
188    void wait(integral, memory_order = memory_order::seq_cst) const noexcept;
189    void notify_one() volatile noexcept;
190    void notify_one() noexcept;
191    void notify_all() volatile noexcept;
192    void notify_all() noexcept;
193};
194
195template <class T>
196struct atomic<T*>
197{
198    using value_type = T*;
199    using difference_type = ptrdiff_t;
200
201    static constexpr bool is_always_lock_free;
202    bool is_lock_free() const volatile noexcept;
203    bool is_lock_free() const noexcept;
204
205    atomic() noexcept = default; // until C++20
206    constexpr atomic() noexcept; // since C++20
207    constexpr atomic(T* desr) noexcept;
208    atomic(const atomic&) = delete;
209    atomic& operator=(const atomic&) = delete;
210    atomic& operator=(const atomic&) volatile = delete;
211
212    T* load(memory_order m = memory_order_seq_cst) const volatile noexcept;
213    T* load(memory_order m = memory_order_seq_cst) const noexcept;
214    operator T*() const volatile noexcept;
215    operator T*() const noexcept;
216    void store(T* desr, memory_order m = memory_order_seq_cst) volatile noexcept;
217    void store(T* desr, memory_order m = memory_order_seq_cst) noexcept;
218    T* operator=(T*) volatile noexcept;
219    T* operator=(T*) noexcept;
220
221    T* exchange(T* desr, memory_order m = memory_order_seq_cst) volatile noexcept;
222    T* exchange(T* desr, memory_order m = memory_order_seq_cst) noexcept;
223    bool compare_exchange_weak(T*& expc, T* desr,
224                               memory_order s, memory_order f) volatile noexcept;
225    bool compare_exchange_weak(T*& expc, T* desr,
226                               memory_order s, memory_order f) noexcept;
227    bool compare_exchange_strong(T*& expc, T* desr,
228                                 memory_order s, memory_order f) volatile noexcept;
229    bool compare_exchange_strong(T*& expc, T* desr,
230                                 memory_order s, memory_order f) noexcept;
231    bool compare_exchange_weak(T*& expc, T* desr,
232                               memory_order m = memory_order_seq_cst) volatile noexcept;
233    bool compare_exchange_weak(T*& expc, T* desr,
234                               memory_order m = memory_order_seq_cst) noexcept;
235    bool compare_exchange_strong(T*& expc, T* desr,
236                                memory_order m = memory_order_seq_cst) volatile noexcept;
237    bool compare_exchange_strong(T*& expc, T* desr,
238                                 memory_order m = memory_order_seq_cst) noexcept;
239    T* fetch_add(ptrdiff_t op, memory_order m = memory_order_seq_cst) volatile noexcept;
240    T* fetch_add(ptrdiff_t op, memory_order m = memory_order_seq_cst) noexcept;
241    T* fetch_sub(ptrdiff_t op, memory_order m = memory_order_seq_cst) volatile noexcept;
242    T* fetch_sub(ptrdiff_t op, memory_order m = memory_order_seq_cst) noexcept;
243
244    T* operator++(int) volatile noexcept;
245    T* operator++(int) noexcept;
246    T* operator--(int) volatile noexcept;
247    T* operator--(int) noexcept;
248    T* operator++() volatile noexcept;
249    T* operator++() noexcept;
250    T* operator--() volatile noexcept;
251    T* operator--() noexcept;
252    T* operator+=(ptrdiff_t op) volatile noexcept;
253    T* operator+=(ptrdiff_t op) noexcept;
254    T* operator-=(ptrdiff_t op) volatile noexcept;
255    T* operator-=(ptrdiff_t op) noexcept;
256
257    void wait(T*, memory_order = memory_order::seq_cst) const volatile noexcept;
258    void wait(T*, memory_order = memory_order::seq_cst) const noexcept;
259    void notify_one() volatile noexcept;
260    void notify_one() noexcept;
261    void notify_all() volatile noexcept;
262    void notify_all() noexcept;
263};
264
265
266// [atomics.nonmembers], non-member functions
267template<class T>
268  bool atomic_is_lock_free(const volatile atomic<T>*) noexcept;
269template<class T>
270  bool atomic_is_lock_free(const atomic<T>*) noexcept;
271template<class T>
272  void atomic_store(volatile atomic<T>*, atomic<T>::value_type) noexcept;
273template<class T>
274  void atomic_store(atomic<T>*, atomic<T>::value_type) noexcept;
275template<class T>
276  void atomic_store_explicit(volatile atomic<T>*, atomic<T>::value_type,
277                             memory_order) noexcept;
278template<class T>
279  void atomic_store_explicit(atomic<T>*, atomic<T>::value_type,
280                             memory_order) noexcept;
281template<class T>
282  T atomic_load(const volatile atomic<T>*) noexcept;
283template<class T>
284  T atomic_load(const atomic<T>*) noexcept;
285template<class T>
286  T atomic_load_explicit(const volatile atomic<T>*, memory_order) noexcept;
287template<class T>
288  T atomic_load_explicit(const atomic<T>*, memory_order) noexcept;
289template<class T>
290  T atomic_exchange(volatile atomic<T>*, atomic<T>::value_type) noexcept;
291template<class T>
292  T atomic_exchange(atomic<T>*, atomic<T>::value_type) noexcept;
293template<class T>
294  T atomic_exchange_explicit(volatile atomic<T>*, atomic<T>::value_type,
295                             memory_order) noexcept;
296template<class T>
297  T atomic_exchange_explicit(atomic<T>*, atomic<T>::value_type,
298                             memory_order) noexcept;
299template<class T>
300  bool atomic_compare_exchange_weak(volatile atomic<T>*, atomic<T>::value_type*,
301                                    atomic<T>::value_type) noexcept;
302template<class T>
303  bool atomic_compare_exchange_weak(atomic<T>*, atomic<T>::value_type*,
304                                    atomic<T>::value_type) noexcept;
305template<class T>
306  bool atomic_compare_exchange_strong(volatile atomic<T>*, atomic<T>::value_type*,
307                                      atomic<T>::value_type) noexcept;
308template<class T>
309  bool atomic_compare_exchange_strong(atomic<T>*, atomic<T>::value_type*,
310                                      atomic<T>::value_type) noexcept;
311template<class T>
312  bool atomic_compare_exchange_weak_explicit(volatile atomic<T>*, atomic<T>::value_type*,
313                                             atomic<T>::value_type,
314                                             memory_order, memory_order) noexcept;
315template<class T>
316  bool atomic_compare_exchange_weak_explicit(atomic<T>*, atomic<T>::value_type*,
317                                             atomic<T>::value_type,
318                                             memory_order, memory_order) noexcept;
319template<class T>
320  bool atomic_compare_exchange_strong_explicit(volatile atomic<T>*, atomic<T>::value_type*,
321                                               atomic<T>::value_type,
322                                               memory_order, memory_order) noexcept;
323template<class T>
324  bool atomic_compare_exchange_strong_explicit(atomic<T>*, atomic<T>::value_type*,
325                                               atomic<T>::value_type,
326                                               memory_order, memory_order) noexcept;
327
328template<class T>
329  T atomic_fetch_add(volatile atomic<T>*, atomic<T>::difference_type) noexcept;
330template<class T>
331  T atomic_fetch_add(atomic<T>*, atomic<T>::difference_type) noexcept;
332template<class T>
333  T atomic_fetch_add_explicit(volatile atomic<T>*, atomic<T>::difference_type,
334                              memory_order) noexcept;
335template<class T>
336  T atomic_fetch_add_explicit(atomic<T>*, atomic<T>::difference_type,
337                              memory_order) noexcept;
338template<class T>
339  T atomic_fetch_sub(volatile atomic<T>*, atomic<T>::difference_type) noexcept;
340template<class T>
341  T atomic_fetch_sub(atomic<T>*, atomic<T>::difference_type) noexcept;
342template<class T>
343  T atomic_fetch_sub_explicit(volatile atomic<T>*, atomic<T>::difference_type,
344                              memory_order) noexcept;
345template<class T>
346  T atomic_fetch_sub_explicit(atomic<T>*, atomic<T>::difference_type,
347                              memory_order) noexcept;
348template<class T>
349  T atomic_fetch_and(volatile atomic<T>*, atomic<T>::value_type) noexcept;
350template<class T>
351  T atomic_fetch_and(atomic<T>*, atomic<T>::value_type) noexcept;
352template<class T>
353  T atomic_fetch_and_explicit(volatile atomic<T>*, atomic<T>::value_type,
354                              memory_order) noexcept;
355template<class T>
356  T atomic_fetch_and_explicit(atomic<T>*, atomic<T>::value_type,
357                              memory_order) noexcept;
358template<class T>
359  T atomic_fetch_or(volatile atomic<T>*, atomic<T>::value_type) noexcept;
360template<class T>
361  T atomic_fetch_or(atomic<T>*, atomic<T>::value_type) noexcept;
362template<class T>
363  T atomic_fetch_or_explicit(volatile atomic<T>*, atomic<T>::value_type,
364                             memory_order) noexcept;
365template<class T>
366  T atomic_fetch_or_explicit(atomic<T>*, atomic<T>::value_type,
367                             memory_order) noexcept;
368template<class T>
369  T atomic_fetch_xor(volatile atomic<T>*, atomic<T>::value_type) noexcept;
370template<class T>
371  T atomic_fetch_xor(atomic<T>*, atomic<T>::value_type) noexcept;
372template<class T>
373  T atomic_fetch_xor_explicit(volatile atomic<T>*, atomic<T>::value_type,
374                              memory_order) noexcept;
375template<class T>
376  T atomic_fetch_xor_explicit(atomic<T>*, atomic<T>::value_type,
377                              memory_order) noexcept;
378
379template<class T>
380  void atomic_wait(const volatile atomic<T>*, atomic<T>::value_type);
381template<class T>
382  void atomic_wait(const atomic<T>*, atomic<T>::value_type);
383template<class T>
384  void atomic_wait_explicit(const volatile atomic<T>*, atomic<T>::value_type,
385                            memory_order);
386template<class T>
387  void atomic_wait_explicit(const atomic<T>*, atomic<T>::value_type,
388                            memory_order);
389template<class T>
390  void atomic_notify_one(volatile atomic<T>*);
391template<class T>
392  void atomic_notify_one(atomic<T>*);
393template<class T>
394  void atomic_notify_all(volatile atomic<T>*);
395template<class T>
396  void atomic_notify_all(atomic<T>*);
397
398// Atomics for standard typedef types
399
400typedef atomic<bool>               atomic_bool;
401typedef atomic<char>               atomic_char;
402typedef atomic<signed char>        atomic_schar;
403typedef atomic<unsigned char>      atomic_uchar;
404typedef atomic<short>              atomic_short;
405typedef atomic<unsigned short>     atomic_ushort;
406typedef atomic<int>                atomic_int;
407typedef atomic<unsigned int>       atomic_uint;
408typedef atomic<long>               atomic_long;
409typedef atomic<unsigned long>      atomic_ulong;
410typedef atomic<long long>          atomic_llong;
411typedef atomic<unsigned long long> atomic_ullong;
412typedef atomic<char8_t>            atomic_char8_t; // C++20
413typedef atomic<char16_t>           atomic_char16_t;
414typedef atomic<char32_t>           atomic_char32_t;
415typedef atomic<wchar_t>            atomic_wchar_t;
416
417typedef atomic<int_least8_t>   atomic_int_least8_t;
418typedef atomic<uint_least8_t>  atomic_uint_least8_t;
419typedef atomic<int_least16_t>  atomic_int_least16_t;
420typedef atomic<uint_least16_t> atomic_uint_least16_t;
421typedef atomic<int_least32_t>  atomic_int_least32_t;
422typedef atomic<uint_least32_t> atomic_uint_least32_t;
423typedef atomic<int_least64_t>  atomic_int_least64_t;
424typedef atomic<uint_least64_t> atomic_uint_least64_t;
425
426typedef atomic<int_fast8_t>   atomic_int_fast8_t;
427typedef atomic<uint_fast8_t>  atomic_uint_fast8_t;
428typedef atomic<int_fast16_t>  atomic_int_fast16_t;
429typedef atomic<uint_fast16_t> atomic_uint_fast16_t;
430typedef atomic<int_fast32_t>  atomic_int_fast32_t;
431typedef atomic<uint_fast32_t> atomic_uint_fast32_t;
432typedef atomic<int_fast64_t>  atomic_int_fast64_t;
433typedef atomic<uint_fast64_t> atomic_uint_fast64_t;
434
435typedef atomic<int8_t>   atomic_int8_t;
436typedef atomic<uint8_t>  atomic_uint8_t;
437typedef atomic<int16_t>  atomic_int16_t;
438typedef atomic<uint16_t> atomic_uint16_t;
439typedef atomic<int32_t>  atomic_int32_t;
440typedef atomic<uint32_t> atomic_uint32_t;
441typedef atomic<int64_t>  atomic_int64_t;
442typedef atomic<uint64_t> atomic_uint64_t;
443
444typedef atomic<intptr_t>  atomic_intptr_t;
445typedef atomic<uintptr_t> atomic_uintptr_t;
446typedef atomic<size_t>    atomic_size_t;
447typedef atomic<ptrdiff_t> atomic_ptrdiff_t;
448typedef atomic<intmax_t>  atomic_intmax_t;
449typedef atomic<uintmax_t> atomic_uintmax_t;
450
451// flag type and operations
452
453typedef struct atomic_flag
454{
455    atomic_flag() noexcept = default; // until C++20
456    constexpr atomic_flag() noexcept; // since C++20
457    atomic_flag(const atomic_flag&) = delete;
458    atomic_flag& operator=(const atomic_flag&) = delete;
459    atomic_flag& operator=(const atomic_flag&) volatile = delete;
460
461    bool test(memory_order m = memory_order_seq_cst) volatile noexcept;
462    bool test(memory_order m = memory_order_seq_cst) noexcept;
463    bool test_and_set(memory_order m = memory_order_seq_cst) volatile noexcept;
464    bool test_and_set(memory_order m = memory_order_seq_cst) noexcept;
465    void clear(memory_order m = memory_order_seq_cst) volatile noexcept;
466    void clear(memory_order m = memory_order_seq_cst) noexcept;
467
468    void wait(bool, memory_order = memory_order::seq_cst) const volatile noexcept;
469    void wait(bool, memory_order = memory_order::seq_cst) const noexcept;
470    void notify_one() volatile noexcept;
471    void notify_one() noexcept;
472    void notify_all() volatile noexcept;
473    void notify_all() noexcept;
474} atomic_flag;
475
476bool atomic_flag_test(volatile atomic_flag* obj) noexcept;
477bool atomic_flag_test(atomic_flag* obj) noexcept;
478bool atomic_flag_test_explicit(volatile atomic_flag* obj,
479                               memory_order m) noexcept;
480bool atomic_flag_test_explicit(atomic_flag* obj, memory_order m) noexcept;
481bool atomic_flag_test_and_set(volatile atomic_flag* obj) noexcept;
482bool atomic_flag_test_and_set(atomic_flag* obj) noexcept;
483bool atomic_flag_test_and_set_explicit(volatile atomic_flag* obj,
484                                       memory_order m) noexcept;
485bool atomic_flag_test_and_set_explicit(atomic_flag* obj, memory_order m) noexcept;
486void atomic_flag_clear(volatile atomic_flag* obj) noexcept;
487void atomic_flag_clear(atomic_flag* obj) noexcept;
488void atomic_flag_clear_explicit(volatile atomic_flag* obj, memory_order m) noexcept;
489void atomic_flag_clear_explicit(atomic_flag* obj, memory_order m) noexcept;
490
491void atomic_wait(const volatile atomic_flag* obj, T old) noexcept;
492void atomic_wait(const atomic_flag* obj, T old) noexcept;
493void atomic_wait_explicit(const volatile atomic_flag* obj, T old, memory_order m) noexcept;
494void atomic_wait_explicit(const atomic_flag* obj, T old, memory_order m) noexcept;
495void atomic_one(volatile atomic_flag* obj) noexcept;
496void atomic_one(atomic_flag* obj) noexcept;
497void atomic_all(volatile atomic_flag* obj) noexcept;
498void atomic_all(atomic_flag* obj) noexcept;
499
500// fences
501
502void atomic_thread_fence(memory_order m) noexcept;
503void atomic_signal_fence(memory_order m) noexcept;
504
505// deprecated
506
507template <class T>
508  void atomic_init(volatile atomic<T>* obj, atomic<T>::value_type desr) noexcept;
509
510template <class T>
511  void atomic_init(atomic<T>* obj, atomic<T>::value_type desr) noexcept;
512
513#define ATOMIC_VAR_INIT(value) see below
514
515#define ATOMIC_FLAG_INIT see below
516
517}  // std
518
519*/
520
521#include <__assert> // all public C++ headers provide the assertion handler
522#include <__availability>
523#include <__chrono/duration.h>
524#include <__config>
525#include <__thread/poll_with_backoff.h>
526#include <__thread/timed_backoff_policy.h>
527#include <cstddef>
528#include <cstdint>
529#include <cstring>
530#include <type_traits>
531#include <version>
532
533#ifndef _LIBCPP_HAS_NO_THREADS
534# include <__threading_support>
535#endif
536
537#ifndef _LIBCPP_REMOVE_TRANSITIVE_INCLUDES
538#  include <chrono>
539#endif
540
541#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
542#  pragma GCC system_header
543#endif
544
545#ifdef _LIBCPP_HAS_NO_ATOMIC_HEADER
546# error <atomic> is not implemented
547#endif
548#ifdef kill_dependency
549# error <atomic> is incompatible with <stdatomic.h> before C++23. Please compile with -std=c++23.
550#endif
551
552#define _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m) \
553  _LIBCPP_DIAGNOSE_WARNING(__m == memory_order_consume || \
554                           __m == memory_order_acquire || \
555                           __m == memory_order_acq_rel,   \
556                        "memory order argument to atomic operation is invalid")
557
558#define _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m) \
559  _LIBCPP_DIAGNOSE_WARNING(__m == memory_order_release || \
560                           __m == memory_order_acq_rel,   \
561                        "memory order argument to atomic operation is invalid")
562
563#define _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__m, __f) \
564  _LIBCPP_DIAGNOSE_WARNING(__f == memory_order_release || \
565                           __f == memory_order_acq_rel,   \
566                        "memory order argument to atomic operation is invalid")
567
568_LIBCPP_BEGIN_NAMESPACE_STD
569
570// Figure out what the underlying type for `memory_order` would be if it were
571// declared as an unscoped enum (accounting for -fshort-enums). Use this result
572// to pin the underlying type in C++20.
573enum __legacy_memory_order {
574    __mo_relaxed,
575    __mo_consume,
576    __mo_acquire,
577    __mo_release,
578    __mo_acq_rel,
579    __mo_seq_cst
580};
581
582typedef underlying_type<__legacy_memory_order>::type __memory_order_underlying_t;
583
584#if _LIBCPP_STD_VER > 17
585
586enum class memory_order : __memory_order_underlying_t {
587  relaxed = __mo_relaxed,
588  consume = __mo_consume,
589  acquire = __mo_acquire,
590  release = __mo_release,
591  acq_rel = __mo_acq_rel,
592  seq_cst = __mo_seq_cst
593};
594
595inline constexpr auto memory_order_relaxed = memory_order::relaxed;
596inline constexpr auto memory_order_consume = memory_order::consume;
597inline constexpr auto memory_order_acquire = memory_order::acquire;
598inline constexpr auto memory_order_release = memory_order::release;
599inline constexpr auto memory_order_acq_rel = memory_order::acq_rel;
600inline constexpr auto memory_order_seq_cst = memory_order::seq_cst;
601
602#else
603
604typedef enum memory_order {
605  memory_order_relaxed = __mo_relaxed,
606  memory_order_consume = __mo_consume,
607  memory_order_acquire = __mo_acquire,
608  memory_order_release = __mo_release,
609  memory_order_acq_rel = __mo_acq_rel,
610  memory_order_seq_cst = __mo_seq_cst,
611} memory_order;
612
613#endif // _LIBCPP_STD_VER > 17
614
615template <typename _Tp> _LIBCPP_INLINE_VISIBILITY
616bool __cxx_nonatomic_compare_equal(_Tp const& __lhs, _Tp const& __rhs) {
617    return _VSTD::memcmp(&__lhs, &__rhs, sizeof(_Tp)) == 0;
618}
619
620static_assert((is_same<underlying_type<memory_order>::type, __memory_order_underlying_t>::value),
621  "unexpected underlying type for std::memory_order");
622
623#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP) || \
624    defined(_LIBCPP_ATOMIC_ONLY_USE_BUILTINS)
625
626// [atomics.types.generic]p1 guarantees _Tp is trivially copyable. Because
627// the default operator= in an object is not volatile, a byte-by-byte copy
628// is required.
629template <typename _Tp, typename _Tv> _LIBCPP_INLINE_VISIBILITY
630typename enable_if<is_assignable<_Tp&, _Tv>::value>::type
631__cxx_atomic_assign_volatile(_Tp& __a_value, _Tv const& __val) {
632  __a_value = __val;
633}
634template <typename _Tp, typename _Tv> _LIBCPP_INLINE_VISIBILITY
635typename enable_if<is_assignable<_Tp&, _Tv>::value>::type
636__cxx_atomic_assign_volatile(_Tp volatile& __a_value, _Tv volatile const& __val) {
637  volatile char* __to = reinterpret_cast<volatile char*>(&__a_value);
638  volatile char* __end = __to + sizeof(_Tp);
639  volatile const char* __from = reinterpret_cast<volatile const char*>(&__val);
640  while (__to != __end)
641    *__to++ = *__from++;
642}
643
644#endif
645
646#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP)
647
648template <typename _Tp>
649struct __cxx_atomic_base_impl {
650
651  _LIBCPP_INLINE_VISIBILITY
652#ifndef _LIBCPP_CXX03_LANG
653    __cxx_atomic_base_impl() _NOEXCEPT = default;
654#else
655    __cxx_atomic_base_impl() _NOEXCEPT : __a_value() {}
656#endif // _LIBCPP_CXX03_LANG
657  _LIBCPP_CONSTEXPR explicit __cxx_atomic_base_impl(_Tp value) _NOEXCEPT
658    : __a_value(value) {}
659  _Tp __a_value;
660};
661
662_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR int __to_gcc_order(memory_order __order) {
663  // Avoid switch statement to make this a constexpr.
664  return __order == memory_order_relaxed ? __ATOMIC_RELAXED:
665         (__order == memory_order_acquire ? __ATOMIC_ACQUIRE:
666          (__order == memory_order_release ? __ATOMIC_RELEASE:
667           (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST:
668            (__order == memory_order_acq_rel ? __ATOMIC_ACQ_REL:
669              __ATOMIC_CONSUME))));
670}
671
672_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR int __to_gcc_failure_order(memory_order __order) {
673  // Avoid switch statement to make this a constexpr.
674  return __order == memory_order_relaxed ? __ATOMIC_RELAXED:
675         (__order == memory_order_acquire ? __ATOMIC_ACQUIRE:
676          (__order == memory_order_release ? __ATOMIC_RELAXED:
677           (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST:
678            (__order == memory_order_acq_rel ? __ATOMIC_ACQUIRE:
679              __ATOMIC_CONSUME))));
680}
681
682template <typename _Tp>
683_LIBCPP_INLINE_VISIBILITY
684void __cxx_atomic_init(volatile __cxx_atomic_base_impl<_Tp>* __a,  _Tp __val) {
685  __cxx_atomic_assign_volatile(__a->__a_value, __val);
686}
687
688template <typename _Tp>
689_LIBCPP_INLINE_VISIBILITY
690void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp>* __a,  _Tp __val) {
691  __a->__a_value = __val;
692}
693
694_LIBCPP_INLINE_VISIBILITY inline
695void __cxx_atomic_thread_fence(memory_order __order) {
696  __atomic_thread_fence(__to_gcc_order(__order));
697}
698
699_LIBCPP_INLINE_VISIBILITY inline
700void __cxx_atomic_signal_fence(memory_order __order) {
701  __atomic_signal_fence(__to_gcc_order(__order));
702}
703
704template <typename _Tp>
705_LIBCPP_INLINE_VISIBILITY
706void __cxx_atomic_store(volatile __cxx_atomic_base_impl<_Tp>* __a,  _Tp __val,
707                        memory_order __order) {
708  __atomic_store(&__a->__a_value, &__val,
709                 __to_gcc_order(__order));
710}
711
712template <typename _Tp>
713_LIBCPP_INLINE_VISIBILITY
714void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp>* __a,  _Tp __val,
715                        memory_order __order) {
716  __atomic_store(&__a->__a_value, &__val,
717                 __to_gcc_order(__order));
718}
719
720template <typename _Tp>
721_LIBCPP_INLINE_VISIBILITY
722_Tp __cxx_atomic_load(const volatile __cxx_atomic_base_impl<_Tp>* __a,
723                      memory_order __order) {
724  _Tp __ret;
725  __atomic_load(&__a->__a_value, &__ret,
726                __to_gcc_order(__order));
727  return __ret;
728}
729
730template <typename _Tp>
731_LIBCPP_INLINE_VISIBILITY
732_Tp __cxx_atomic_load(const __cxx_atomic_base_impl<_Tp>* __a, memory_order __order) {
733  _Tp __ret;
734  __atomic_load(&__a->__a_value, &__ret,
735                __to_gcc_order(__order));
736  return __ret;
737}
738
739template <typename _Tp>
740_LIBCPP_INLINE_VISIBILITY
741_Tp __cxx_atomic_exchange(volatile __cxx_atomic_base_impl<_Tp>* __a,
742                          _Tp __value, memory_order __order) {
743  _Tp __ret;
744  __atomic_exchange(&__a->__a_value, &__value, &__ret,
745                    __to_gcc_order(__order));
746  return __ret;
747}
748
749template <typename _Tp>
750_LIBCPP_INLINE_VISIBILITY
751_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp>* __a, _Tp __value,
752                          memory_order __order) {
753  _Tp __ret;
754  __atomic_exchange(&__a->__a_value, &__value, &__ret,
755                    __to_gcc_order(__order));
756  return __ret;
757}
758
759template <typename _Tp>
760_LIBCPP_INLINE_VISIBILITY
761bool __cxx_atomic_compare_exchange_strong(
762    volatile __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value,
763    memory_order __success, memory_order __failure) {
764  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
765                                   false,
766                                   __to_gcc_order(__success),
767                                   __to_gcc_failure_order(__failure));
768}
769
770template <typename _Tp>
771_LIBCPP_INLINE_VISIBILITY
772bool __cxx_atomic_compare_exchange_strong(
773    __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success,
774    memory_order __failure) {
775  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
776                                   false,
777                                   __to_gcc_order(__success),
778                                   __to_gcc_failure_order(__failure));
779}
780
781template <typename _Tp>
782_LIBCPP_INLINE_VISIBILITY
783bool __cxx_atomic_compare_exchange_weak(
784    volatile __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value,
785    memory_order __success, memory_order __failure) {
786  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
787                                   true,
788                                   __to_gcc_order(__success),
789                                   __to_gcc_failure_order(__failure));
790}
791
792template <typename _Tp>
793_LIBCPP_INLINE_VISIBILITY
794bool __cxx_atomic_compare_exchange_weak(
795    __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success,
796    memory_order __failure) {
797  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
798                                   true,
799                                   __to_gcc_order(__success),
800                                   __to_gcc_failure_order(__failure));
801}
802
803template <typename _Tp>
804struct __skip_amt { enum {value = 1}; };
805
806template <typename _Tp>
807struct __skip_amt<_Tp*> { enum {value = sizeof(_Tp)}; };
808
809// FIXME: Haven't figured out what the spec says about using arrays with
810// atomic_fetch_add. Force a failure rather than creating bad behavior.
811template <typename _Tp>
812struct __skip_amt<_Tp[]> { };
813template <typename _Tp, int n>
814struct __skip_amt<_Tp[n]> { };
815
816template <typename _Tp, typename _Td>
817_LIBCPP_INLINE_VISIBILITY
818_Tp __cxx_atomic_fetch_add(volatile __cxx_atomic_base_impl<_Tp>* __a,
819                           _Td __delta, memory_order __order) {
820  return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
821                            __to_gcc_order(__order));
822}
823
824template <typename _Tp, typename _Td>
825_LIBCPP_INLINE_VISIBILITY
826_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp>* __a, _Td __delta,
827                           memory_order __order) {
828  return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
829                            __to_gcc_order(__order));
830}
831
832template <typename _Tp, typename _Td>
833_LIBCPP_INLINE_VISIBILITY
834_Tp __cxx_atomic_fetch_sub(volatile __cxx_atomic_base_impl<_Tp>* __a,
835                           _Td __delta, memory_order __order) {
836  return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
837                            __to_gcc_order(__order));
838}
839
840template <typename _Tp, typename _Td>
841_LIBCPP_INLINE_VISIBILITY
842_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp>* __a, _Td __delta,
843                           memory_order __order) {
844  return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
845                            __to_gcc_order(__order));
846}
847
848template <typename _Tp>
849_LIBCPP_INLINE_VISIBILITY
850_Tp __cxx_atomic_fetch_and(volatile __cxx_atomic_base_impl<_Tp>* __a,
851                           _Tp __pattern, memory_order __order) {
852  return __atomic_fetch_and(&__a->__a_value, __pattern,
853                            __to_gcc_order(__order));
854}
855
856template <typename _Tp>
857_LIBCPP_INLINE_VISIBILITY
858_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp>* __a,
859                           _Tp __pattern, memory_order __order) {
860  return __atomic_fetch_and(&__a->__a_value, __pattern,
861                            __to_gcc_order(__order));
862}
863
864template <typename _Tp>
865_LIBCPP_INLINE_VISIBILITY
866_Tp __cxx_atomic_fetch_or(volatile __cxx_atomic_base_impl<_Tp>* __a,
867                          _Tp __pattern, memory_order __order) {
868  return __atomic_fetch_or(&__a->__a_value, __pattern,
869                           __to_gcc_order(__order));
870}
871
872template <typename _Tp>
873_LIBCPP_INLINE_VISIBILITY
874_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp>* __a, _Tp __pattern,
875                          memory_order __order) {
876  return __atomic_fetch_or(&__a->__a_value, __pattern,
877                           __to_gcc_order(__order));
878}
879
880template <typename _Tp>
881_LIBCPP_INLINE_VISIBILITY
882_Tp __cxx_atomic_fetch_xor(volatile __cxx_atomic_base_impl<_Tp>* __a,
883                           _Tp __pattern, memory_order __order) {
884  return __atomic_fetch_xor(&__a->__a_value, __pattern,
885                            __to_gcc_order(__order));
886}
887
888template <typename _Tp>
889_LIBCPP_INLINE_VISIBILITY
890_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp>* __a, _Tp __pattern,
891                           memory_order __order) {
892  return __atomic_fetch_xor(&__a->__a_value, __pattern,
893                            __to_gcc_order(__order));
894}
895
896#define __cxx_atomic_is_lock_free(__s) __atomic_is_lock_free(__s, 0)
897
898#elif defined(_LIBCPP_HAS_C_ATOMIC_IMP)
899
900template <typename _Tp>
901struct __cxx_atomic_base_impl {
902
903  _LIBCPP_INLINE_VISIBILITY
904#ifndef _LIBCPP_CXX03_LANG
905    __cxx_atomic_base_impl() _NOEXCEPT = default;
906#else
907    __cxx_atomic_base_impl() _NOEXCEPT : __a_value() {}
908#endif // _LIBCPP_CXX03_LANG
909  _LIBCPP_CONSTEXPR explicit __cxx_atomic_base_impl(_Tp __value) _NOEXCEPT
910    : __a_value(__value) {}
911  _LIBCPP_DISABLE_EXTENSION_WARNING _Atomic(_Tp) __a_value;
912};
913
914#define __cxx_atomic_is_lock_free(__s) __c11_atomic_is_lock_free(__s)
915
916_LIBCPP_INLINE_VISIBILITY inline
917void __cxx_atomic_thread_fence(memory_order __order) _NOEXCEPT {
918    __c11_atomic_thread_fence(static_cast<__memory_order_underlying_t>(__order));
919}
920
921_LIBCPP_INLINE_VISIBILITY inline
922void __cxx_atomic_signal_fence(memory_order __order) _NOEXCEPT {
923    __c11_atomic_signal_fence(static_cast<__memory_order_underlying_t>(__order));
924}
925
926template<class _Tp>
927_LIBCPP_INLINE_VISIBILITY
928void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __val) _NOEXCEPT {
929    __c11_atomic_init(&__a->__a_value, __val);
930}
931template<class _Tp>
932_LIBCPP_INLINE_VISIBILITY
933void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp> * __a, _Tp __val) _NOEXCEPT {
934    __c11_atomic_init(&__a->__a_value, __val);
935}
936
937template<class _Tp>
938_LIBCPP_INLINE_VISIBILITY
939void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __val, memory_order __order) _NOEXCEPT {
940    __c11_atomic_store(&__a->__a_value, __val, static_cast<__memory_order_underlying_t>(__order));
941}
942template<class _Tp>
943_LIBCPP_INLINE_VISIBILITY
944void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp> * __a, _Tp __val, memory_order __order) _NOEXCEPT {
945    __c11_atomic_store(&__a->__a_value, __val, static_cast<__memory_order_underlying_t>(__order));
946}
947
948template<class _Tp>
949_LIBCPP_INLINE_VISIBILITY
950_Tp __cxx_atomic_load(__cxx_atomic_base_impl<_Tp> const volatile* __a, memory_order __order) _NOEXCEPT {
951    using __ptr_type = typename remove_const<decltype(__a->__a_value)>::type*;
952    return __c11_atomic_load(const_cast<__ptr_type>(&__a->__a_value), static_cast<__memory_order_underlying_t>(__order));
953}
954template<class _Tp>
955_LIBCPP_INLINE_VISIBILITY
956_Tp __cxx_atomic_load(__cxx_atomic_base_impl<_Tp> const* __a, memory_order __order) _NOEXCEPT {
957    using __ptr_type = typename remove_const<decltype(__a->__a_value)>::type*;
958    return __c11_atomic_load(const_cast<__ptr_type>(&__a->__a_value), static_cast<__memory_order_underlying_t>(__order));
959}
960
961template<class _Tp>
962_LIBCPP_INLINE_VISIBILITY
963_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __value, memory_order __order) _NOEXCEPT {
964    return __c11_atomic_exchange(&__a->__a_value, __value, static_cast<__memory_order_underlying_t>(__order));
965}
966template<class _Tp>
967_LIBCPP_INLINE_VISIBILITY
968_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp> * __a, _Tp __value, memory_order __order) _NOEXCEPT {
969    return __c11_atomic_exchange(&__a->__a_value, __value, static_cast<__memory_order_underlying_t>(__order));
970}
971
972_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR memory_order __to_failure_order(memory_order __order) {
973  // Avoid switch statement to make this a constexpr.
974  return __order == memory_order_release ? memory_order_relaxed:
975         (__order == memory_order_acq_rel ? memory_order_acquire:
976             __order);
977}
978
979template<class _Tp>
980_LIBCPP_INLINE_VISIBILITY
981bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
982    return __c11_atomic_compare_exchange_strong(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
983}
984template<class _Tp>
985_LIBCPP_INLINE_VISIBILITY
986bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_base_impl<_Tp> * __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
987    return __c11_atomic_compare_exchange_strong(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
988}
989
990template<class _Tp>
991_LIBCPP_INLINE_VISIBILITY
992bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
993    return __c11_atomic_compare_exchange_weak(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
994}
995template<class _Tp>
996_LIBCPP_INLINE_VISIBILITY
997bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_base_impl<_Tp> * __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
998    return __c11_atomic_compare_exchange_weak(&__a->__a_value, __expected, __value,  static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
999}
1000
1001template<class _Tp>
1002_LIBCPP_INLINE_VISIBILITY
1003_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __delta, memory_order __order) _NOEXCEPT {
1004    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1005}
1006template<class _Tp>
1007_LIBCPP_INLINE_VISIBILITY
1008_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp> * __a, _Tp __delta, memory_order __order) _NOEXCEPT {
1009    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1010}
1011
1012template<class _Tp>
1013_LIBCPP_INLINE_VISIBILITY
1014_Tp* __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
1015    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1016}
1017template<class _Tp>
1018_LIBCPP_INLINE_VISIBILITY
1019_Tp* __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp*> * __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
1020    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1021}
1022
1023template<class _Tp>
1024_LIBCPP_INLINE_VISIBILITY
1025_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __delta, memory_order __order) _NOEXCEPT {
1026    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1027}
1028template<class _Tp>
1029_LIBCPP_INLINE_VISIBILITY
1030_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp> * __a, _Tp __delta, memory_order __order) _NOEXCEPT {
1031    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1032}
1033template<class _Tp>
1034_LIBCPP_INLINE_VISIBILITY
1035_Tp* __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
1036    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1037}
1038template<class _Tp>
1039_LIBCPP_INLINE_VISIBILITY
1040_Tp* __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp*> * __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
1041    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1042}
1043
1044template<class _Tp>
1045_LIBCPP_INLINE_VISIBILITY
1046_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1047    return __c11_atomic_fetch_and(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1048}
1049template<class _Tp>
1050_LIBCPP_INLINE_VISIBILITY
1051_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1052    return __c11_atomic_fetch_and(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1053}
1054
1055template<class _Tp>
1056_LIBCPP_INLINE_VISIBILITY
1057_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1058    return __c11_atomic_fetch_or(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1059}
1060template<class _Tp>
1061_LIBCPP_INLINE_VISIBILITY
1062_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1063    return __c11_atomic_fetch_or(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1064}
1065
1066template<class _Tp>
1067_LIBCPP_INLINE_VISIBILITY
1068_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1069    return __c11_atomic_fetch_xor(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1070}
1071template<class _Tp>
1072_LIBCPP_INLINE_VISIBILITY
1073_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1074    return __c11_atomic_fetch_xor(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1075}
1076
1077#endif // _LIBCPP_HAS_GCC_ATOMIC_IMP, _LIBCPP_HAS_C_ATOMIC_IMP
1078
1079template <class _Tp>
1080_LIBCPP_INLINE_VISIBILITY
1081_Tp kill_dependency(_Tp __y) _NOEXCEPT
1082{
1083    return __y;
1084}
1085
1086#if defined(__CLANG_ATOMIC_BOOL_LOCK_FREE)
1087# define ATOMIC_BOOL_LOCK_FREE      __CLANG_ATOMIC_BOOL_LOCK_FREE
1088# define ATOMIC_CHAR_LOCK_FREE      __CLANG_ATOMIC_CHAR_LOCK_FREE
1089#ifndef _LIBCPP_HAS_NO_CHAR8_T
1090# define ATOMIC_CHAR8_T_LOCK_FREE   __CLANG_ATOMIC_CHAR8_T_LOCK_FREE
1091#endif
1092# define ATOMIC_CHAR16_T_LOCK_FREE  __CLANG_ATOMIC_CHAR16_T_LOCK_FREE
1093# define ATOMIC_CHAR32_T_LOCK_FREE  __CLANG_ATOMIC_CHAR32_T_LOCK_FREE
1094# define ATOMIC_WCHAR_T_LOCK_FREE   __CLANG_ATOMIC_WCHAR_T_LOCK_FREE
1095# define ATOMIC_SHORT_LOCK_FREE     __CLANG_ATOMIC_SHORT_LOCK_FREE
1096# define ATOMIC_INT_LOCK_FREE       __CLANG_ATOMIC_INT_LOCK_FREE
1097# define ATOMIC_LONG_LOCK_FREE      __CLANG_ATOMIC_LONG_LOCK_FREE
1098# define ATOMIC_LLONG_LOCK_FREE     __CLANG_ATOMIC_LLONG_LOCK_FREE
1099# define ATOMIC_POINTER_LOCK_FREE   __CLANG_ATOMIC_POINTER_LOCK_FREE
1100#elif defined(__GCC_ATOMIC_BOOL_LOCK_FREE)
1101# define ATOMIC_BOOL_LOCK_FREE      __GCC_ATOMIC_BOOL_LOCK_FREE
1102# define ATOMIC_CHAR_LOCK_FREE      __GCC_ATOMIC_CHAR_LOCK_FREE
1103#ifndef _LIBCPP_HAS_NO_CHAR8_T
1104# define ATOMIC_CHAR8_T_LOCK_FREE   __GCC_ATOMIC_CHAR8_T_LOCK_FREE
1105#endif
1106# define ATOMIC_CHAR16_T_LOCK_FREE  __GCC_ATOMIC_CHAR16_T_LOCK_FREE
1107# define ATOMIC_CHAR32_T_LOCK_FREE  __GCC_ATOMIC_CHAR32_T_LOCK_FREE
1108# define ATOMIC_WCHAR_T_LOCK_FREE   __GCC_ATOMIC_WCHAR_T_LOCK_FREE
1109# define ATOMIC_SHORT_LOCK_FREE     __GCC_ATOMIC_SHORT_LOCK_FREE
1110# define ATOMIC_INT_LOCK_FREE       __GCC_ATOMIC_INT_LOCK_FREE
1111# define ATOMIC_LONG_LOCK_FREE      __GCC_ATOMIC_LONG_LOCK_FREE
1112# define ATOMIC_LLONG_LOCK_FREE     __GCC_ATOMIC_LLONG_LOCK_FREE
1113# define ATOMIC_POINTER_LOCK_FREE   __GCC_ATOMIC_POINTER_LOCK_FREE
1114#endif
1115
1116template <class _Tp>
1117struct __libcpp_is_always_lock_free {
1118  // __atomic_always_lock_free is available in all Standard modes
1119  static const bool __value = __atomic_always_lock_free(sizeof(_Tp), 0);
1120};
1121
1122#ifdef _LIBCPP_ATOMIC_ONLY_USE_BUILTINS
1123
1124template<typename _Tp>
1125struct __cxx_atomic_lock_impl {
1126
1127  _LIBCPP_INLINE_VISIBILITY
1128  __cxx_atomic_lock_impl() _NOEXCEPT
1129    : __a_value(), __a_lock(0) {}
1130  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR explicit
1131  __cxx_atomic_lock_impl(_Tp value) _NOEXCEPT
1132    : __a_value(value), __a_lock(0) {}
1133
1134  _Tp __a_value;
1135  mutable __cxx_atomic_base_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_lock;
1136
1137  _LIBCPP_INLINE_VISIBILITY void __lock() const volatile {
1138    while(1 == __cxx_atomic_exchange(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(true), memory_order_acquire))
1139        /*spin*/;
1140  }
1141  _LIBCPP_INLINE_VISIBILITY void __lock() const {
1142    while(1 == __cxx_atomic_exchange(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(true), memory_order_acquire))
1143        /*spin*/;
1144  }
1145  _LIBCPP_INLINE_VISIBILITY void __unlock() const volatile {
1146    __cxx_atomic_store(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(false), memory_order_release);
1147  }
1148  _LIBCPP_INLINE_VISIBILITY void __unlock() const {
1149    __cxx_atomic_store(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(false), memory_order_release);
1150  }
1151  _LIBCPP_INLINE_VISIBILITY _Tp __read() const volatile {
1152    __lock();
1153    _Tp __old;
1154    __cxx_atomic_assign_volatile(__old, __a_value);
1155    __unlock();
1156    return __old;
1157  }
1158  _LIBCPP_INLINE_VISIBILITY _Tp __read() const {
1159    __lock();
1160    _Tp __old = __a_value;
1161    __unlock();
1162    return __old;
1163  }
1164};
1165
1166template <typename _Tp>
1167_LIBCPP_INLINE_VISIBILITY
1168void __cxx_atomic_init(volatile __cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val) {
1169  __cxx_atomic_assign_volatile(__a->__a_value, __val);
1170}
1171template <typename _Tp>
1172_LIBCPP_INLINE_VISIBILITY
1173void __cxx_atomic_init(__cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val) {
1174  __a->__a_value = __val;
1175}
1176
1177template <typename _Tp>
1178_LIBCPP_INLINE_VISIBILITY
1179void __cxx_atomic_store(volatile __cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val, memory_order) {
1180  __a->__lock();
1181  __cxx_atomic_assign_volatile(__a->__a_value, __val);
1182  __a->__unlock();
1183}
1184template <typename _Tp>
1185_LIBCPP_INLINE_VISIBILITY
1186void __cxx_atomic_store(__cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val, memory_order) {
1187  __a->__lock();
1188  __a->__a_value = __val;
1189  __a->__unlock();
1190}
1191
1192template <typename _Tp>
1193_LIBCPP_INLINE_VISIBILITY
1194_Tp __cxx_atomic_load(const volatile __cxx_atomic_lock_impl<_Tp>* __a, memory_order) {
1195  return __a->__read();
1196}
1197template <typename _Tp>
1198_LIBCPP_INLINE_VISIBILITY
1199_Tp __cxx_atomic_load(const __cxx_atomic_lock_impl<_Tp>* __a, memory_order) {
1200  return __a->__read();
1201}
1202
1203template <typename _Tp>
1204_LIBCPP_INLINE_VISIBILITY
1205_Tp __cxx_atomic_exchange(volatile __cxx_atomic_lock_impl<_Tp>* __a, _Tp __value, memory_order) {
1206  __a->__lock();
1207  _Tp __old;
1208  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1209  __cxx_atomic_assign_volatile(__a->__a_value, __value);
1210  __a->__unlock();
1211  return __old;
1212}
1213template <typename _Tp>
1214_LIBCPP_INLINE_VISIBILITY
1215_Tp __cxx_atomic_exchange(__cxx_atomic_lock_impl<_Tp>* __a, _Tp __value, memory_order) {
1216  __a->__lock();
1217  _Tp __old = __a->__a_value;
1218  __a->__a_value = __value;
1219  __a->__unlock();
1220  return __old;
1221}
1222
1223template <typename _Tp>
1224_LIBCPP_INLINE_VISIBILITY
1225bool __cxx_atomic_compare_exchange_strong(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1226                                          _Tp* __expected, _Tp __value, memory_order, memory_order) {
1227  _Tp __temp;
1228  __a->__lock();
1229  __cxx_atomic_assign_volatile(__temp, __a->__a_value);
1230  bool __ret = (_VSTD::memcmp(&__temp, __expected, sizeof(_Tp)) == 0);
1231  if(__ret)
1232    __cxx_atomic_assign_volatile(__a->__a_value, __value);
1233  else
1234    __cxx_atomic_assign_volatile(*__expected, __a->__a_value);
1235  __a->__unlock();
1236  return __ret;
1237}
1238template <typename _Tp>
1239_LIBCPP_INLINE_VISIBILITY
1240bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_lock_impl<_Tp>* __a,
1241                                          _Tp* __expected, _Tp __value, memory_order, memory_order) {
1242  __a->__lock();
1243  bool __ret = (_VSTD::memcmp(&__a->__a_value, __expected, sizeof(_Tp)) == 0);
1244  if(__ret)
1245    _VSTD::memcpy(&__a->__a_value, &__value, sizeof(_Tp));
1246  else
1247    _VSTD::memcpy(__expected, &__a->__a_value, sizeof(_Tp));
1248  __a->__unlock();
1249  return __ret;
1250}
1251
1252template <typename _Tp>
1253_LIBCPP_INLINE_VISIBILITY
1254bool __cxx_atomic_compare_exchange_weak(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1255                                        _Tp* __expected, _Tp __value, memory_order, memory_order) {
1256  _Tp __temp;
1257  __a->__lock();
1258  __cxx_atomic_assign_volatile(__temp, __a->__a_value);
1259  bool __ret = (_VSTD::memcmp(&__temp, __expected, sizeof(_Tp)) == 0);
1260  if(__ret)
1261    __cxx_atomic_assign_volatile(__a->__a_value, __value);
1262  else
1263    __cxx_atomic_assign_volatile(*__expected, __a->__a_value);
1264  __a->__unlock();
1265  return __ret;
1266}
1267template <typename _Tp>
1268_LIBCPP_INLINE_VISIBILITY
1269bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_lock_impl<_Tp>* __a,
1270                                        _Tp* __expected, _Tp __value, memory_order, memory_order) {
1271  __a->__lock();
1272  bool __ret = (_VSTD::memcmp(&__a->__a_value, __expected, sizeof(_Tp)) == 0);
1273  if(__ret)
1274    _VSTD::memcpy(&__a->__a_value, &__value, sizeof(_Tp));
1275  else
1276    _VSTD::memcpy(__expected, &__a->__a_value, sizeof(_Tp));
1277  __a->__unlock();
1278  return __ret;
1279}
1280
1281template <typename _Tp, typename _Td>
1282_LIBCPP_INLINE_VISIBILITY
1283_Tp __cxx_atomic_fetch_add(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1284                           _Td __delta, memory_order) {
1285  __a->__lock();
1286  _Tp __old;
1287  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1288  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old + __delta));
1289  __a->__unlock();
1290  return __old;
1291}
1292template <typename _Tp, typename _Td>
1293_LIBCPP_INLINE_VISIBILITY
1294_Tp __cxx_atomic_fetch_add(__cxx_atomic_lock_impl<_Tp>* __a,
1295                           _Td __delta, memory_order) {
1296  __a->__lock();
1297  _Tp __old = __a->__a_value;
1298  __a->__a_value += __delta;
1299  __a->__unlock();
1300  return __old;
1301}
1302
1303template <typename _Tp, typename _Td>
1304_LIBCPP_INLINE_VISIBILITY
1305_Tp* __cxx_atomic_fetch_add(volatile __cxx_atomic_lock_impl<_Tp*>* __a,
1306                           ptrdiff_t __delta, memory_order) {
1307  __a->__lock();
1308  _Tp* __old;
1309  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1310  __cxx_atomic_assign_volatile(__a->__a_value, __old + __delta);
1311  __a->__unlock();
1312  return __old;
1313}
1314template <typename _Tp, typename _Td>
1315_LIBCPP_INLINE_VISIBILITY
1316_Tp* __cxx_atomic_fetch_add(__cxx_atomic_lock_impl<_Tp*>* __a,
1317                           ptrdiff_t __delta, memory_order) {
1318  __a->__lock();
1319  _Tp* __old = __a->__a_value;
1320  __a->__a_value += __delta;
1321  __a->__unlock();
1322  return __old;
1323}
1324
1325template <typename _Tp, typename _Td>
1326_LIBCPP_INLINE_VISIBILITY
1327_Tp __cxx_atomic_fetch_sub(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1328                           _Td __delta, memory_order) {
1329  __a->__lock();
1330  _Tp __old;
1331  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1332  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old - __delta));
1333  __a->__unlock();
1334  return __old;
1335}
1336template <typename _Tp, typename _Td>
1337_LIBCPP_INLINE_VISIBILITY
1338_Tp __cxx_atomic_fetch_sub(__cxx_atomic_lock_impl<_Tp>* __a,
1339                           _Td __delta, memory_order) {
1340  __a->__lock();
1341  _Tp __old = __a->__a_value;
1342  __a->__a_value -= __delta;
1343  __a->__unlock();
1344  return __old;
1345}
1346
1347template <typename _Tp>
1348_LIBCPP_INLINE_VISIBILITY
1349_Tp __cxx_atomic_fetch_and(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1350                           _Tp __pattern, memory_order) {
1351  __a->__lock();
1352  _Tp __old;
1353  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1354  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old & __pattern));
1355  __a->__unlock();
1356  return __old;
1357}
1358template <typename _Tp>
1359_LIBCPP_INLINE_VISIBILITY
1360_Tp __cxx_atomic_fetch_and(__cxx_atomic_lock_impl<_Tp>* __a,
1361                           _Tp __pattern, memory_order) {
1362  __a->__lock();
1363  _Tp __old = __a->__a_value;
1364  __a->__a_value &= __pattern;
1365  __a->__unlock();
1366  return __old;
1367}
1368
1369template <typename _Tp>
1370_LIBCPP_INLINE_VISIBILITY
1371_Tp __cxx_atomic_fetch_or(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1372                          _Tp __pattern, memory_order) {
1373  __a->__lock();
1374  _Tp __old;
1375  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1376  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old | __pattern));
1377  __a->__unlock();
1378  return __old;
1379}
1380template <typename _Tp>
1381_LIBCPP_INLINE_VISIBILITY
1382_Tp __cxx_atomic_fetch_or(__cxx_atomic_lock_impl<_Tp>* __a,
1383                          _Tp __pattern, memory_order) {
1384  __a->__lock();
1385  _Tp __old = __a->__a_value;
1386  __a->__a_value |= __pattern;
1387  __a->__unlock();
1388  return __old;
1389}
1390
1391template <typename _Tp>
1392_LIBCPP_INLINE_VISIBILITY
1393_Tp __cxx_atomic_fetch_xor(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1394                           _Tp __pattern, memory_order) {
1395  __a->__lock();
1396  _Tp __old;
1397  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1398  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old ^ __pattern));
1399  __a->__unlock();
1400  return __old;
1401}
1402template <typename _Tp>
1403_LIBCPP_INLINE_VISIBILITY
1404_Tp __cxx_atomic_fetch_xor(__cxx_atomic_lock_impl<_Tp>* __a,
1405                           _Tp __pattern, memory_order) {
1406  __a->__lock();
1407  _Tp __old = __a->__a_value;
1408  __a->__a_value ^= __pattern;
1409  __a->__unlock();
1410  return __old;
1411}
1412
1413template <typename _Tp,
1414          typename _Base = typename conditional<__libcpp_is_always_lock_free<_Tp>::__value,
1415                                                __cxx_atomic_base_impl<_Tp>,
1416                                                __cxx_atomic_lock_impl<_Tp> >::type>
1417#else
1418template <typename _Tp,
1419          typename _Base = __cxx_atomic_base_impl<_Tp> >
1420#endif //_LIBCPP_ATOMIC_ONLY_USE_BUILTINS
1421struct __cxx_atomic_impl : public _Base {
1422    static_assert(is_trivially_copyable<_Tp>::value,
1423      "std::atomic<T> requires that 'T' be a trivially copyable type");
1424
1425  _LIBCPP_INLINE_VISIBILITY __cxx_atomic_impl() _NOEXCEPT = default;
1426  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR explicit __cxx_atomic_impl(_Tp __value) _NOEXCEPT
1427    : _Base(__value) {}
1428};
1429
1430#if defined(__linux__) || (defined(_AIX) && !defined(__64BIT__))
1431    using __cxx_contention_t = int32_t;
1432#else
1433    using __cxx_contention_t = int64_t;
1434#endif // __linux__ || (_AIX && !__64BIT__)
1435
1436using __cxx_atomic_contention_t = __cxx_atomic_impl<__cxx_contention_t>;
1437
1438#if defined(_LIBCPP_HAS_NO_THREADS)
1439#   define _LIBCPP_HAS_NO_PLATFORM_WAIT
1440#endif
1441
1442// TODO:
1443// _LIBCPP_HAS_NO_PLATFORM_WAIT is currently a "dead" macro, in the sense that
1444// it is not tied anywhere into the build system or even documented. We should
1445// clean it up because it is technically never defined except when threads are
1446// disabled. We should clean it up in its own changeset in case we break "bad"
1447// users.
1448#ifndef _LIBCPP_HAS_NO_PLATFORM_WAIT
1449
1450_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(void const volatile*);
1451_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(void const volatile*);
1452_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(void const volatile*);
1453_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(void const volatile*, __cxx_contention_t);
1454
1455_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_contention_t const volatile*);
1456_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_contention_t const volatile*);
1457_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile*);
1458_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(__cxx_atomic_contention_t const volatile*, __cxx_contention_t);
1459
1460template <class _Atp, class _Fn>
1461struct __libcpp_atomic_wait_backoff_impl {
1462    _Atp* __a;
1463    _Fn __test_fn;
1464    _LIBCPP_AVAILABILITY_SYNC
1465    _LIBCPP_INLINE_VISIBILITY bool operator()(chrono::nanoseconds __elapsed) const
1466    {
1467        if(__elapsed > chrono::microseconds(64))
1468        {
1469            auto const __monitor = __libcpp_atomic_monitor(__a);
1470            if(__test_fn())
1471                return true;
1472            __libcpp_atomic_wait(__a, __monitor);
1473        }
1474        else if(__elapsed > chrono::microseconds(4))
1475            __libcpp_thread_yield();
1476        else
1477            {} // poll
1478        return false;
1479    }
1480};
1481
1482template <class _Atp, class _Fn>
1483_LIBCPP_AVAILABILITY_SYNC
1484_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Fn && __test_fn)
1485{
1486    __libcpp_atomic_wait_backoff_impl<_Atp, typename decay<_Fn>::type> __backoff_fn = {__a, __test_fn};
1487    return __libcpp_thread_poll_with_backoff(__test_fn, __backoff_fn);
1488}
1489
1490#else // _LIBCPP_HAS_NO_PLATFORM_WAIT
1491
1492template <class _Tp>
1493_LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_all(__cxx_atomic_impl<_Tp> const volatile*) { }
1494template <class _Tp>
1495_LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_one(__cxx_atomic_impl<_Tp> const volatile*) { }
1496template <class _Atp, class _Fn>
1497_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp*, _Fn && __test_fn)
1498{
1499#if defined(_LIBCPP_HAS_NO_THREADS)
1500    using _Policy = __spinning_backoff_policy;
1501#else
1502    using _Policy = __libcpp_timed_backoff_policy;
1503#endif
1504    return __libcpp_thread_poll_with_backoff(__test_fn, _Policy());
1505}
1506
1507#endif // _LIBCPP_HAS_NO_PLATFORM_WAIT
1508
1509template <class _Atp, class _Tp>
1510struct __cxx_atomic_wait_test_fn_impl {
1511    _Atp* __a;
1512    _Tp __val;
1513    memory_order __order;
1514    _LIBCPP_INLINE_VISIBILITY bool operator()() const
1515    {
1516        return !__cxx_nonatomic_compare_equal(__cxx_atomic_load(__a, __order), __val);
1517    }
1518};
1519
1520template <class _Atp, class _Tp>
1521_LIBCPP_AVAILABILITY_SYNC
1522_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Tp const __val, memory_order __order)
1523{
1524    __cxx_atomic_wait_test_fn_impl<_Atp, _Tp> __test_fn = {__a, __val, __order};
1525    return __cxx_atomic_wait(__a, __test_fn);
1526}
1527
1528// general atomic<T>
1529
1530template <class _Tp, bool = is_integral<_Tp>::value && !is_same<_Tp, bool>::value>
1531struct __atomic_base  // false
1532{
1533    mutable __cxx_atomic_impl<_Tp> __a_;
1534
1535#if defined(__cpp_lib_atomic_is_always_lock_free)
1536  static _LIBCPP_CONSTEXPR bool is_always_lock_free = __libcpp_is_always_lock_free<__cxx_atomic_impl<_Tp> >::__value;
1537#endif
1538
1539    _LIBCPP_INLINE_VISIBILITY
1540    bool is_lock_free() const volatile _NOEXCEPT
1541        {return __cxx_atomic_is_lock_free(sizeof(_Tp));}
1542    _LIBCPP_INLINE_VISIBILITY
1543    bool is_lock_free() const _NOEXCEPT
1544        {return static_cast<__atomic_base const volatile*>(this)->is_lock_free();}
1545    _LIBCPP_INLINE_VISIBILITY
1546    void store(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1547      _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
1548        {__cxx_atomic_store(&__a_, __d, __m);}
1549    _LIBCPP_INLINE_VISIBILITY
1550    void store(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1551      _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
1552        {__cxx_atomic_store(&__a_, __d, __m);}
1553    _LIBCPP_INLINE_VISIBILITY
1554    _Tp load(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
1555      _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
1556        {return __cxx_atomic_load(&__a_, __m);}
1557    _LIBCPP_INLINE_VISIBILITY
1558    _Tp load(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
1559      _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
1560        {return __cxx_atomic_load(&__a_, __m);}
1561    _LIBCPP_INLINE_VISIBILITY
1562    operator _Tp() const volatile _NOEXCEPT {return load();}
1563    _LIBCPP_INLINE_VISIBILITY
1564    operator _Tp() const _NOEXCEPT          {return load();}
1565    _LIBCPP_INLINE_VISIBILITY
1566    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1567        {return __cxx_atomic_exchange(&__a_, __d, __m);}
1568    _LIBCPP_INLINE_VISIBILITY
1569    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1570        {return __cxx_atomic_exchange(&__a_, __d, __m);}
1571    _LIBCPP_INLINE_VISIBILITY
1572    bool compare_exchange_weak(_Tp& __e, _Tp __d,
1573                               memory_order __s, memory_order __f) volatile _NOEXCEPT
1574      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
1575        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
1576    _LIBCPP_INLINE_VISIBILITY
1577    bool compare_exchange_weak(_Tp& __e, _Tp __d,
1578                               memory_order __s, memory_order __f) _NOEXCEPT
1579      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
1580        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
1581    _LIBCPP_INLINE_VISIBILITY
1582    bool compare_exchange_strong(_Tp& __e, _Tp __d,
1583                                 memory_order __s, memory_order __f) volatile _NOEXCEPT
1584      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
1585        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
1586    _LIBCPP_INLINE_VISIBILITY
1587    bool compare_exchange_strong(_Tp& __e, _Tp __d,
1588                                 memory_order __s, memory_order __f) _NOEXCEPT
1589      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
1590        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
1591    _LIBCPP_INLINE_VISIBILITY
1592    bool compare_exchange_weak(_Tp& __e, _Tp __d,
1593                              memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1594        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
1595    _LIBCPP_INLINE_VISIBILITY
1596    bool compare_exchange_weak(_Tp& __e, _Tp __d,
1597                               memory_order __m = memory_order_seq_cst) _NOEXCEPT
1598        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
1599    _LIBCPP_INLINE_VISIBILITY
1600    bool compare_exchange_strong(_Tp& __e, _Tp __d,
1601                              memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1602        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
1603    _LIBCPP_INLINE_VISIBILITY
1604    bool compare_exchange_strong(_Tp& __e, _Tp __d,
1605                                 memory_order __m = memory_order_seq_cst) _NOEXCEPT
1606        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
1607
1608    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void wait(_Tp __v, memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
1609        {__cxx_atomic_wait(&__a_, __v, __m);}
1610    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void wait(_Tp __v, memory_order __m = memory_order_seq_cst) const _NOEXCEPT
1611        {__cxx_atomic_wait(&__a_, __v, __m);}
1612    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_one() volatile _NOEXCEPT
1613        {__cxx_atomic_notify_one(&__a_);}
1614    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_one() _NOEXCEPT
1615        {__cxx_atomic_notify_one(&__a_);}
1616    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_all() volatile _NOEXCEPT
1617        {__cxx_atomic_notify_all(&__a_);}
1618    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_all() _NOEXCEPT
1619        {__cxx_atomic_notify_all(&__a_);}
1620
1621#if _LIBCPP_STD_VER > 17
1622    _LIBCPP_INLINE_VISIBILITY constexpr
1623    __atomic_base() noexcept(is_nothrow_default_constructible_v<_Tp>) : __a_(_Tp()) {}
1624#else
1625    _LIBCPP_INLINE_VISIBILITY
1626    __atomic_base() _NOEXCEPT = default;
1627#endif
1628
1629    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1630    __atomic_base(_Tp __d) _NOEXCEPT : __a_(__d) {}
1631
1632    __atomic_base(const __atomic_base&) = delete;
1633};
1634
1635#if defined(__cpp_lib_atomic_is_always_lock_free)
1636template <class _Tp, bool __b>
1637_LIBCPP_CONSTEXPR bool __atomic_base<_Tp, __b>::is_always_lock_free;
1638#endif
1639
1640// atomic<Integral>
1641
1642template <class _Tp>
1643struct __atomic_base<_Tp, true>
1644    : public __atomic_base<_Tp, false>
1645{
1646    typedef __atomic_base<_Tp, false> __base;
1647
1648    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1649    __atomic_base() _NOEXCEPT = default;
1650
1651    _LIBCPP_INLINE_VISIBILITY
1652    _LIBCPP_CONSTEXPR __atomic_base(_Tp __d) _NOEXCEPT : __base(__d) {}
1653
1654    _LIBCPP_INLINE_VISIBILITY
1655    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1656        {return __cxx_atomic_fetch_add(&this->__a_, __op, __m);}
1657    _LIBCPP_INLINE_VISIBILITY
1658    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1659        {return __cxx_atomic_fetch_add(&this->__a_, __op, __m);}
1660    _LIBCPP_INLINE_VISIBILITY
1661    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1662        {return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
1663    _LIBCPP_INLINE_VISIBILITY
1664    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1665        {return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
1666    _LIBCPP_INLINE_VISIBILITY
1667    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1668        {return __cxx_atomic_fetch_and(&this->__a_, __op, __m);}
1669    _LIBCPP_INLINE_VISIBILITY
1670    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1671        {return __cxx_atomic_fetch_and(&this->__a_, __op, __m);}
1672    _LIBCPP_INLINE_VISIBILITY
1673    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1674        {return __cxx_atomic_fetch_or(&this->__a_, __op, __m);}
1675    _LIBCPP_INLINE_VISIBILITY
1676    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1677        {return __cxx_atomic_fetch_or(&this->__a_, __op, __m);}
1678    _LIBCPP_INLINE_VISIBILITY
1679    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1680        {return __cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
1681    _LIBCPP_INLINE_VISIBILITY
1682    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1683        {return __cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
1684
1685    _LIBCPP_INLINE_VISIBILITY
1686    _Tp operator++(int) volatile _NOEXCEPT      {return fetch_add(_Tp(1));}
1687    _LIBCPP_INLINE_VISIBILITY
1688    _Tp operator++(int) _NOEXCEPT               {return fetch_add(_Tp(1));}
1689    _LIBCPP_INLINE_VISIBILITY
1690    _Tp operator--(int) volatile _NOEXCEPT      {return fetch_sub(_Tp(1));}
1691    _LIBCPP_INLINE_VISIBILITY
1692    _Tp operator--(int) _NOEXCEPT               {return fetch_sub(_Tp(1));}
1693    _LIBCPP_INLINE_VISIBILITY
1694    _Tp operator++() volatile _NOEXCEPT         {return fetch_add(_Tp(1)) + _Tp(1);}
1695    _LIBCPP_INLINE_VISIBILITY
1696    _Tp operator++() _NOEXCEPT                  {return fetch_add(_Tp(1)) + _Tp(1);}
1697    _LIBCPP_INLINE_VISIBILITY
1698    _Tp operator--() volatile _NOEXCEPT         {return fetch_sub(_Tp(1)) - _Tp(1);}
1699    _LIBCPP_INLINE_VISIBILITY
1700    _Tp operator--() _NOEXCEPT                  {return fetch_sub(_Tp(1)) - _Tp(1);}
1701    _LIBCPP_INLINE_VISIBILITY
1702    _Tp operator+=(_Tp __op) volatile _NOEXCEPT {return fetch_add(__op) + __op;}
1703    _LIBCPP_INLINE_VISIBILITY
1704    _Tp operator+=(_Tp __op) _NOEXCEPT          {return fetch_add(__op) + __op;}
1705    _LIBCPP_INLINE_VISIBILITY
1706    _Tp operator-=(_Tp __op) volatile _NOEXCEPT {return fetch_sub(__op) - __op;}
1707    _LIBCPP_INLINE_VISIBILITY
1708    _Tp operator-=(_Tp __op) _NOEXCEPT          {return fetch_sub(__op) - __op;}
1709    _LIBCPP_INLINE_VISIBILITY
1710    _Tp operator&=(_Tp __op) volatile _NOEXCEPT {return fetch_and(__op) & __op;}
1711    _LIBCPP_INLINE_VISIBILITY
1712    _Tp operator&=(_Tp __op) _NOEXCEPT          {return fetch_and(__op) & __op;}
1713    _LIBCPP_INLINE_VISIBILITY
1714    _Tp operator|=(_Tp __op) volatile _NOEXCEPT {return fetch_or(__op) | __op;}
1715    _LIBCPP_INLINE_VISIBILITY
1716    _Tp operator|=(_Tp __op) _NOEXCEPT          {return fetch_or(__op) | __op;}
1717    _LIBCPP_INLINE_VISIBILITY
1718    _Tp operator^=(_Tp __op) volatile _NOEXCEPT {return fetch_xor(__op) ^ __op;}
1719    _LIBCPP_INLINE_VISIBILITY
1720    _Tp operator^=(_Tp __op) _NOEXCEPT          {return fetch_xor(__op) ^ __op;}
1721};
1722
1723// atomic<T>
1724
1725template <class _Tp>
1726struct atomic
1727    : public __atomic_base<_Tp>
1728{
1729    typedef __atomic_base<_Tp> __base;
1730    typedef _Tp value_type;
1731    typedef value_type difference_type;
1732
1733#if _LIBCPP_STD_VER > 17
1734    _LIBCPP_INLINE_VISIBILITY
1735    atomic() = default;
1736#else
1737    _LIBCPP_INLINE_VISIBILITY
1738    atomic() _NOEXCEPT = default;
1739#endif
1740
1741    _LIBCPP_INLINE_VISIBILITY
1742    _LIBCPP_CONSTEXPR atomic(_Tp __d) _NOEXCEPT : __base(__d) {}
1743
1744    _LIBCPP_INLINE_VISIBILITY
1745    _Tp operator=(_Tp __d) volatile _NOEXCEPT
1746        {__base::store(__d); return __d;}
1747    _LIBCPP_INLINE_VISIBILITY
1748    _Tp operator=(_Tp __d) _NOEXCEPT
1749        {__base::store(__d); return __d;}
1750
1751    atomic& operator=(const atomic&) = delete;
1752    atomic& operator=(const atomic&) volatile = delete;
1753};
1754
1755// atomic<T*>
1756
1757template <class _Tp>
1758struct atomic<_Tp*>
1759    : public __atomic_base<_Tp*>
1760{
1761    typedef __atomic_base<_Tp*> __base;
1762    typedef _Tp* value_type;
1763    typedef ptrdiff_t difference_type;
1764
1765    _LIBCPP_INLINE_VISIBILITY
1766    atomic() _NOEXCEPT = default;
1767
1768    _LIBCPP_INLINE_VISIBILITY
1769    _LIBCPP_CONSTEXPR atomic(_Tp* __d) _NOEXCEPT : __base(__d) {}
1770
1771    _LIBCPP_INLINE_VISIBILITY
1772    _Tp* operator=(_Tp* __d) volatile _NOEXCEPT
1773        {__base::store(__d); return __d;}
1774    _LIBCPP_INLINE_VISIBILITY
1775    _Tp* operator=(_Tp* __d) _NOEXCEPT
1776        {__base::store(__d); return __d;}
1777
1778    _LIBCPP_INLINE_VISIBILITY
1779    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT {
1780        // __atomic_fetch_add accepts function pointers, guard against them.
1781        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
1782        return __cxx_atomic_fetch_add(&this->__a_, __op, __m);
1783    }
1784
1785    _LIBCPP_INLINE_VISIBILITY
1786    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT {
1787        // __atomic_fetch_add accepts function pointers, guard against them.
1788        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
1789        return __cxx_atomic_fetch_add(&this->__a_, __op, __m);
1790    }
1791
1792    _LIBCPP_INLINE_VISIBILITY
1793    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT {
1794        // __atomic_fetch_add accepts function pointers, guard against them.
1795        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
1796        return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);
1797    }
1798
1799    _LIBCPP_INLINE_VISIBILITY
1800    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT {
1801        // __atomic_fetch_add accepts function pointers, guard against them.
1802        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
1803        return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);
1804    }
1805
1806    _LIBCPP_INLINE_VISIBILITY
1807    _Tp* operator++(int) volatile _NOEXCEPT            {return fetch_add(1);}
1808    _LIBCPP_INLINE_VISIBILITY
1809    _Tp* operator++(int) _NOEXCEPT                     {return fetch_add(1);}
1810    _LIBCPP_INLINE_VISIBILITY
1811    _Tp* operator--(int) volatile _NOEXCEPT            {return fetch_sub(1);}
1812    _LIBCPP_INLINE_VISIBILITY
1813    _Tp* operator--(int) _NOEXCEPT                     {return fetch_sub(1);}
1814    _LIBCPP_INLINE_VISIBILITY
1815    _Tp* operator++() volatile _NOEXCEPT               {return fetch_add(1) + 1;}
1816    _LIBCPP_INLINE_VISIBILITY
1817    _Tp* operator++() _NOEXCEPT                        {return fetch_add(1) + 1;}
1818    _LIBCPP_INLINE_VISIBILITY
1819    _Tp* operator--() volatile _NOEXCEPT               {return fetch_sub(1) - 1;}
1820    _LIBCPP_INLINE_VISIBILITY
1821    _Tp* operator--() _NOEXCEPT                        {return fetch_sub(1) - 1;}
1822    _LIBCPP_INLINE_VISIBILITY
1823    _Tp* operator+=(ptrdiff_t __op) volatile _NOEXCEPT {return fetch_add(__op) + __op;}
1824    _LIBCPP_INLINE_VISIBILITY
1825    _Tp* operator+=(ptrdiff_t __op) _NOEXCEPT          {return fetch_add(__op) + __op;}
1826    _LIBCPP_INLINE_VISIBILITY
1827    _Tp* operator-=(ptrdiff_t __op) volatile _NOEXCEPT {return fetch_sub(__op) - __op;}
1828    _LIBCPP_INLINE_VISIBILITY
1829    _Tp* operator-=(ptrdiff_t __op) _NOEXCEPT          {return fetch_sub(__op) - __op;}
1830
1831    atomic& operator=(const atomic&) = delete;
1832    atomic& operator=(const atomic&) volatile = delete;
1833};
1834
1835// atomic_is_lock_free
1836
1837template <class _Tp>
1838_LIBCPP_INLINE_VISIBILITY
1839bool
1840atomic_is_lock_free(const volatile atomic<_Tp>* __o) _NOEXCEPT
1841{
1842    return __o->is_lock_free();
1843}
1844
1845template <class _Tp>
1846_LIBCPP_INLINE_VISIBILITY
1847bool
1848atomic_is_lock_free(const atomic<_Tp>* __o) _NOEXCEPT
1849{
1850    return __o->is_lock_free();
1851}
1852
1853// atomic_init
1854
1855template <class _Tp>
1856_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
1857void
1858atomic_init(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1859{
1860    __cxx_atomic_init(&__o->__a_, __d);
1861}
1862
1863template <class _Tp>
1864_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
1865void
1866atomic_init(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1867{
1868    __cxx_atomic_init(&__o->__a_, __d);
1869}
1870
1871// atomic_store
1872
1873template <class _Tp>
1874_LIBCPP_INLINE_VISIBILITY
1875void
1876atomic_store(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1877{
1878    __o->store(__d);
1879}
1880
1881template <class _Tp>
1882_LIBCPP_INLINE_VISIBILITY
1883void
1884atomic_store(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1885{
1886    __o->store(__d);
1887}
1888
1889// atomic_store_explicit
1890
1891template <class _Tp>
1892_LIBCPP_INLINE_VISIBILITY
1893void
1894atomic_store_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
1895  _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
1896{
1897    __o->store(__d, __m);
1898}
1899
1900template <class _Tp>
1901_LIBCPP_INLINE_VISIBILITY
1902void
1903atomic_store_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
1904  _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
1905{
1906    __o->store(__d, __m);
1907}
1908
1909// atomic_load
1910
1911template <class _Tp>
1912_LIBCPP_INLINE_VISIBILITY
1913_Tp
1914atomic_load(const volatile atomic<_Tp>* __o) _NOEXCEPT
1915{
1916    return __o->load();
1917}
1918
1919template <class _Tp>
1920_LIBCPP_INLINE_VISIBILITY
1921_Tp
1922atomic_load(const atomic<_Tp>* __o) _NOEXCEPT
1923{
1924    return __o->load();
1925}
1926
1927// atomic_load_explicit
1928
1929template <class _Tp>
1930_LIBCPP_INLINE_VISIBILITY
1931_Tp
1932atomic_load_explicit(const volatile atomic<_Tp>* __o, memory_order __m) _NOEXCEPT
1933  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
1934{
1935    return __o->load(__m);
1936}
1937
1938template <class _Tp>
1939_LIBCPP_INLINE_VISIBILITY
1940_Tp
1941atomic_load_explicit(const atomic<_Tp>* __o, memory_order __m) _NOEXCEPT
1942  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
1943{
1944    return __o->load(__m);
1945}
1946
1947// atomic_exchange
1948
1949template <class _Tp>
1950_LIBCPP_INLINE_VISIBILITY
1951_Tp
1952atomic_exchange(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1953{
1954    return __o->exchange(__d);
1955}
1956
1957template <class _Tp>
1958_LIBCPP_INLINE_VISIBILITY
1959_Tp
1960atomic_exchange(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1961{
1962    return __o->exchange(__d);
1963}
1964
1965// atomic_exchange_explicit
1966
1967template <class _Tp>
1968_LIBCPP_INLINE_VISIBILITY
1969_Tp
1970atomic_exchange_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
1971{
1972    return __o->exchange(__d, __m);
1973}
1974
1975template <class _Tp>
1976_LIBCPP_INLINE_VISIBILITY
1977_Tp
1978atomic_exchange_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
1979{
1980    return __o->exchange(__d, __m);
1981}
1982
1983// atomic_compare_exchange_weak
1984
1985template <class _Tp>
1986_LIBCPP_INLINE_VISIBILITY
1987bool
1988atomic_compare_exchange_weak(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1989{
1990    return __o->compare_exchange_weak(*__e, __d);
1991}
1992
1993template <class _Tp>
1994_LIBCPP_INLINE_VISIBILITY
1995bool
1996atomic_compare_exchange_weak(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1997{
1998    return __o->compare_exchange_weak(*__e, __d);
1999}
2000
2001// atomic_compare_exchange_strong
2002
2003template <class _Tp>
2004_LIBCPP_INLINE_VISIBILITY
2005bool
2006atomic_compare_exchange_strong(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
2007{
2008    return __o->compare_exchange_strong(*__e, __d);
2009}
2010
2011template <class _Tp>
2012_LIBCPP_INLINE_VISIBILITY
2013bool
2014atomic_compare_exchange_strong(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
2015{
2016    return __o->compare_exchange_strong(*__e, __d);
2017}
2018
2019// atomic_compare_exchange_weak_explicit
2020
2021template <class _Tp>
2022_LIBCPP_INLINE_VISIBILITY
2023bool
2024atomic_compare_exchange_weak_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e,
2025                                      typename atomic<_Tp>::value_type __d,
2026                                      memory_order __s, memory_order __f) _NOEXCEPT
2027  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
2028{
2029    return __o->compare_exchange_weak(*__e, __d, __s, __f);
2030}
2031
2032template <class _Tp>
2033_LIBCPP_INLINE_VISIBILITY
2034bool
2035atomic_compare_exchange_weak_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d,
2036                                      memory_order __s, memory_order __f) _NOEXCEPT
2037  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
2038{
2039    return __o->compare_exchange_weak(*__e, __d, __s, __f);
2040}
2041
2042// atomic_compare_exchange_strong_explicit
2043
2044template <class _Tp>
2045_LIBCPP_INLINE_VISIBILITY
2046bool
2047atomic_compare_exchange_strong_explicit(volatile atomic<_Tp>* __o,
2048                                        typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d,
2049                                        memory_order __s, memory_order __f) _NOEXCEPT
2050  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
2051{
2052    return __o->compare_exchange_strong(*__e, __d, __s, __f);
2053}
2054
2055template <class _Tp>
2056_LIBCPP_INLINE_VISIBILITY
2057bool
2058atomic_compare_exchange_strong_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e,
2059                                        typename atomic<_Tp>::value_type __d,
2060                                        memory_order __s, memory_order __f) _NOEXCEPT
2061  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
2062{
2063    return __o->compare_exchange_strong(*__e, __d, __s, __f);
2064}
2065
2066// atomic_wait
2067
2068template <class _Tp>
2069_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2070void atomic_wait(const volatile atomic<_Tp>* __o,
2071                 typename atomic<_Tp>::value_type __v) _NOEXCEPT
2072{
2073    return __o->wait(__v);
2074}
2075
2076template <class _Tp>
2077_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2078void atomic_wait(const atomic<_Tp>* __o,
2079                 typename atomic<_Tp>::value_type __v) _NOEXCEPT
2080{
2081    return __o->wait(__v);
2082}
2083
2084// atomic_wait_explicit
2085
2086template <class _Tp>
2087_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2088void atomic_wait_explicit(const volatile atomic<_Tp>* __o,
2089                          typename atomic<_Tp>::value_type __v,
2090                          memory_order __m) _NOEXCEPT
2091  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
2092{
2093    return __o->wait(__v, __m);
2094}
2095
2096template <class _Tp>
2097_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2098void atomic_wait_explicit(const atomic<_Tp>* __o,
2099                          typename atomic<_Tp>::value_type __v,
2100                          memory_order __m) _NOEXCEPT
2101  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
2102{
2103    return __o->wait(__v, __m);
2104}
2105
2106// atomic_notify_one
2107
2108template <class _Tp>
2109_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2110void atomic_notify_one(volatile atomic<_Tp>* __o) _NOEXCEPT
2111{
2112    __o->notify_one();
2113}
2114template <class _Tp>
2115_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2116void atomic_notify_one(atomic<_Tp>* __o) _NOEXCEPT
2117{
2118    __o->notify_one();
2119}
2120
2121// atomic_notify_one
2122
2123template <class _Tp>
2124_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2125void atomic_notify_all(volatile atomic<_Tp>* __o) _NOEXCEPT
2126{
2127    __o->notify_all();
2128}
2129template <class _Tp>
2130_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2131void atomic_notify_all(atomic<_Tp>* __o) _NOEXCEPT
2132{
2133    __o->notify_all();
2134}
2135
2136// atomic_fetch_add
2137
2138template <class _Tp>
2139_LIBCPP_INLINE_VISIBILITY
2140_Tp
2141atomic_fetch_add(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
2142{
2143    return __o->fetch_add(__op);
2144}
2145
2146template <class _Tp>
2147_LIBCPP_INLINE_VISIBILITY
2148_Tp
2149atomic_fetch_add(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
2150{
2151    return __o->fetch_add(__op);
2152}
2153
2154// atomic_fetch_add_explicit
2155
2156template <class _Tp>
2157_LIBCPP_INLINE_VISIBILITY
2158_Tp atomic_fetch_add_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
2159{
2160    return __o->fetch_add(__op, __m);
2161}
2162
2163template <class _Tp>
2164_LIBCPP_INLINE_VISIBILITY
2165_Tp atomic_fetch_add_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
2166{
2167    return __o->fetch_add(__op, __m);
2168}
2169
2170// atomic_fetch_sub
2171
2172template <class _Tp>
2173_LIBCPP_INLINE_VISIBILITY
2174_Tp atomic_fetch_sub(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
2175{
2176    return __o->fetch_sub(__op);
2177}
2178
2179template <class _Tp>
2180_LIBCPP_INLINE_VISIBILITY
2181_Tp atomic_fetch_sub(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
2182{
2183    return __o->fetch_sub(__op);
2184}
2185
2186// atomic_fetch_sub_explicit
2187
2188template <class _Tp>
2189_LIBCPP_INLINE_VISIBILITY
2190_Tp atomic_fetch_sub_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
2191{
2192    return __o->fetch_sub(__op, __m);
2193}
2194
2195template <class _Tp>
2196_LIBCPP_INLINE_VISIBILITY
2197_Tp atomic_fetch_sub_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
2198{
2199    return __o->fetch_sub(__op, __m);
2200}
2201
2202// atomic_fetch_and
2203
2204template <class _Tp>
2205_LIBCPP_INLINE_VISIBILITY
2206typename enable_if
2207<
2208    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2209    _Tp
2210>::type
2211atomic_fetch_and(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2212{
2213    return __o->fetch_and(__op);
2214}
2215
2216template <class _Tp>
2217_LIBCPP_INLINE_VISIBILITY
2218typename enable_if
2219<
2220    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2221    _Tp
2222>::type
2223atomic_fetch_and(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2224{
2225    return __o->fetch_and(__op);
2226}
2227
2228// atomic_fetch_and_explicit
2229
2230template <class _Tp>
2231_LIBCPP_INLINE_VISIBILITY
2232typename enable_if
2233<
2234    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2235    _Tp
2236>::type
2237atomic_fetch_and_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2238{
2239    return __o->fetch_and(__op, __m);
2240}
2241
2242template <class _Tp>
2243_LIBCPP_INLINE_VISIBILITY
2244typename enable_if
2245<
2246    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2247    _Tp
2248>::type
2249atomic_fetch_and_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2250{
2251    return __o->fetch_and(__op, __m);
2252}
2253
2254// atomic_fetch_or
2255
2256template <class _Tp>
2257_LIBCPP_INLINE_VISIBILITY
2258typename enable_if
2259<
2260    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2261    _Tp
2262>::type
2263atomic_fetch_or(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2264{
2265    return __o->fetch_or(__op);
2266}
2267
2268template <class _Tp>
2269_LIBCPP_INLINE_VISIBILITY
2270typename enable_if
2271<
2272    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2273    _Tp
2274>::type
2275atomic_fetch_or(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2276{
2277    return __o->fetch_or(__op);
2278}
2279
2280// atomic_fetch_or_explicit
2281
2282template <class _Tp>
2283_LIBCPP_INLINE_VISIBILITY
2284typename enable_if
2285<
2286    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2287    _Tp
2288>::type
2289atomic_fetch_or_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2290{
2291    return __o->fetch_or(__op, __m);
2292}
2293
2294template <class _Tp>
2295_LIBCPP_INLINE_VISIBILITY
2296typename enable_if
2297<
2298    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2299    _Tp
2300>::type
2301atomic_fetch_or_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2302{
2303    return __o->fetch_or(__op, __m);
2304}
2305
2306// atomic_fetch_xor
2307
2308template <class _Tp>
2309_LIBCPP_INLINE_VISIBILITY
2310typename enable_if
2311<
2312    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2313    _Tp
2314>::type
2315atomic_fetch_xor(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2316{
2317    return __o->fetch_xor(__op);
2318}
2319
2320template <class _Tp>
2321_LIBCPP_INLINE_VISIBILITY
2322typename enable_if
2323<
2324    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2325    _Tp
2326>::type
2327atomic_fetch_xor(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2328{
2329    return __o->fetch_xor(__op);
2330}
2331
2332// atomic_fetch_xor_explicit
2333
2334template <class _Tp>
2335_LIBCPP_INLINE_VISIBILITY
2336typename enable_if
2337<
2338    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2339    _Tp
2340>::type
2341atomic_fetch_xor_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2342{
2343    return __o->fetch_xor(__op, __m);
2344}
2345
2346template <class _Tp>
2347_LIBCPP_INLINE_VISIBILITY
2348typename enable_if
2349<
2350    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2351    _Tp
2352>::type
2353atomic_fetch_xor_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2354{
2355    return __o->fetch_xor(__op, __m);
2356}
2357
2358// flag type and operations
2359
2360typedef struct atomic_flag
2361{
2362    __cxx_atomic_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_;
2363
2364    _LIBCPP_INLINE_VISIBILITY
2365    bool test(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
2366        {return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
2367    _LIBCPP_INLINE_VISIBILITY
2368    bool test(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
2369        {return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
2370
2371    _LIBCPP_INLINE_VISIBILITY
2372    bool test_and_set(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
2373        {return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
2374    _LIBCPP_INLINE_VISIBILITY
2375    bool test_and_set(memory_order __m = memory_order_seq_cst) _NOEXCEPT
2376        {return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
2377    _LIBCPP_INLINE_VISIBILITY
2378    void clear(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
2379        {__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
2380    _LIBCPP_INLINE_VISIBILITY
2381    void clear(memory_order __m = memory_order_seq_cst) _NOEXCEPT
2382        {__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
2383
2384    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2385    void wait(bool __v, memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
2386        {__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
2387    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2388    void wait(bool __v, memory_order __m = memory_order_seq_cst) const _NOEXCEPT
2389        {__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
2390    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2391    void notify_one() volatile _NOEXCEPT
2392        {__cxx_atomic_notify_one(&__a_);}
2393    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2394    void notify_one() _NOEXCEPT
2395        {__cxx_atomic_notify_one(&__a_);}
2396    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2397    void notify_all() volatile _NOEXCEPT
2398        {__cxx_atomic_notify_all(&__a_);}
2399    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2400    void notify_all() _NOEXCEPT
2401        {__cxx_atomic_notify_all(&__a_);}
2402
2403#if _LIBCPP_STD_VER > 17
2404    _LIBCPP_INLINE_VISIBILITY constexpr
2405    atomic_flag() _NOEXCEPT : __a_(false) {}
2406#else
2407    _LIBCPP_INLINE_VISIBILITY
2408    atomic_flag() _NOEXCEPT = default;
2409#endif
2410
2411    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2412    atomic_flag(bool __b) _NOEXCEPT : __a_(__b) {} // EXTENSION
2413
2414    atomic_flag(const atomic_flag&) = delete;
2415    atomic_flag& operator=(const atomic_flag&) = delete;
2416    atomic_flag& operator=(const atomic_flag&) volatile = delete;
2417
2418} atomic_flag;
2419
2420
2421inline _LIBCPP_INLINE_VISIBILITY
2422bool
2423atomic_flag_test(const volatile atomic_flag* __o) _NOEXCEPT
2424{
2425    return __o->test();
2426}
2427
2428inline _LIBCPP_INLINE_VISIBILITY
2429bool
2430atomic_flag_test(const atomic_flag* __o) _NOEXCEPT
2431{
2432    return __o->test();
2433}
2434
2435inline _LIBCPP_INLINE_VISIBILITY
2436bool
2437atomic_flag_test_explicit(const volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
2438{
2439    return __o->test(__m);
2440}
2441
2442inline _LIBCPP_INLINE_VISIBILITY
2443bool
2444atomic_flag_test_explicit(const atomic_flag* __o, memory_order __m) _NOEXCEPT
2445{
2446    return __o->test(__m);
2447}
2448
2449inline _LIBCPP_INLINE_VISIBILITY
2450bool
2451atomic_flag_test_and_set(volatile atomic_flag* __o) _NOEXCEPT
2452{
2453    return __o->test_and_set();
2454}
2455
2456inline _LIBCPP_INLINE_VISIBILITY
2457bool
2458atomic_flag_test_and_set(atomic_flag* __o) _NOEXCEPT
2459{
2460    return __o->test_and_set();
2461}
2462
2463inline _LIBCPP_INLINE_VISIBILITY
2464bool
2465atomic_flag_test_and_set_explicit(volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
2466{
2467    return __o->test_and_set(__m);
2468}
2469
2470inline _LIBCPP_INLINE_VISIBILITY
2471bool
2472atomic_flag_test_and_set_explicit(atomic_flag* __o, memory_order __m) _NOEXCEPT
2473{
2474    return __o->test_and_set(__m);
2475}
2476
2477inline _LIBCPP_INLINE_VISIBILITY
2478void
2479atomic_flag_clear(volatile atomic_flag* __o) _NOEXCEPT
2480{
2481    __o->clear();
2482}
2483
2484inline _LIBCPP_INLINE_VISIBILITY
2485void
2486atomic_flag_clear(atomic_flag* __o) _NOEXCEPT
2487{
2488    __o->clear();
2489}
2490
2491inline _LIBCPP_INLINE_VISIBILITY
2492void
2493atomic_flag_clear_explicit(volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
2494{
2495    __o->clear(__m);
2496}
2497
2498inline _LIBCPP_INLINE_VISIBILITY
2499void
2500atomic_flag_clear_explicit(atomic_flag* __o, memory_order __m) _NOEXCEPT
2501{
2502    __o->clear(__m);
2503}
2504
2505inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2506void
2507atomic_flag_wait(const volatile atomic_flag* __o, bool __v) _NOEXCEPT
2508{
2509    __o->wait(__v);
2510}
2511
2512inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2513void
2514atomic_flag_wait(const atomic_flag* __o, bool __v) _NOEXCEPT
2515{
2516    __o->wait(__v);
2517}
2518
2519inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2520void
2521atomic_flag_wait_explicit(const volatile atomic_flag* __o,
2522                          bool __v, memory_order __m) _NOEXCEPT
2523{
2524    __o->wait(__v, __m);
2525}
2526
2527inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2528void
2529atomic_flag_wait_explicit(const atomic_flag* __o,
2530                          bool __v, memory_order __m) _NOEXCEPT
2531{
2532    __o->wait(__v, __m);
2533}
2534
2535inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2536void
2537atomic_flag_notify_one(volatile atomic_flag* __o) _NOEXCEPT
2538{
2539    __o->notify_one();
2540}
2541
2542inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2543void
2544atomic_flag_notify_one(atomic_flag* __o) _NOEXCEPT
2545{
2546    __o->notify_one();
2547}
2548
2549inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2550void
2551atomic_flag_notify_all(volatile atomic_flag* __o) _NOEXCEPT
2552{
2553    __o->notify_all();
2554}
2555
2556inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2557void
2558atomic_flag_notify_all(atomic_flag* __o) _NOEXCEPT
2559{
2560    __o->notify_all();
2561}
2562
2563// fences
2564
2565inline _LIBCPP_INLINE_VISIBILITY
2566void
2567atomic_thread_fence(memory_order __m) _NOEXCEPT
2568{
2569    __cxx_atomic_thread_fence(__m);
2570}
2571
2572inline _LIBCPP_INLINE_VISIBILITY
2573void
2574atomic_signal_fence(memory_order __m) _NOEXCEPT
2575{
2576    __cxx_atomic_signal_fence(__m);
2577}
2578
2579// Atomics for standard typedef types
2580
2581typedef atomic<bool>               atomic_bool;
2582typedef atomic<char>               atomic_char;
2583typedef atomic<signed char>        atomic_schar;
2584typedef atomic<unsigned char>      atomic_uchar;
2585typedef atomic<short>              atomic_short;
2586typedef atomic<unsigned short>     atomic_ushort;
2587typedef atomic<int>                atomic_int;
2588typedef atomic<unsigned int>       atomic_uint;
2589typedef atomic<long>               atomic_long;
2590typedef atomic<unsigned long>      atomic_ulong;
2591typedef atomic<long long>          atomic_llong;
2592typedef atomic<unsigned long long> atomic_ullong;
2593#ifndef _LIBCPP_HAS_NO_CHAR8_T
2594typedef atomic<char8_t>            atomic_char8_t;
2595#endif
2596typedef atomic<char16_t>           atomic_char16_t;
2597typedef atomic<char32_t>           atomic_char32_t;
2598#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
2599typedef atomic<wchar_t>            atomic_wchar_t;
2600#endif
2601
2602typedef atomic<int_least8_t>   atomic_int_least8_t;
2603typedef atomic<uint_least8_t>  atomic_uint_least8_t;
2604typedef atomic<int_least16_t>  atomic_int_least16_t;
2605typedef atomic<uint_least16_t> atomic_uint_least16_t;
2606typedef atomic<int_least32_t>  atomic_int_least32_t;
2607typedef atomic<uint_least32_t> atomic_uint_least32_t;
2608typedef atomic<int_least64_t>  atomic_int_least64_t;
2609typedef atomic<uint_least64_t> atomic_uint_least64_t;
2610
2611typedef atomic<int_fast8_t>   atomic_int_fast8_t;
2612typedef atomic<uint_fast8_t>  atomic_uint_fast8_t;
2613typedef atomic<int_fast16_t>  atomic_int_fast16_t;
2614typedef atomic<uint_fast16_t> atomic_uint_fast16_t;
2615typedef atomic<int_fast32_t>  atomic_int_fast32_t;
2616typedef atomic<uint_fast32_t> atomic_uint_fast32_t;
2617typedef atomic<int_fast64_t>  atomic_int_fast64_t;
2618typedef atomic<uint_fast64_t> atomic_uint_fast64_t;
2619
2620typedef atomic< int8_t>  atomic_int8_t;
2621typedef atomic<uint8_t>  atomic_uint8_t;
2622typedef atomic< int16_t> atomic_int16_t;
2623typedef atomic<uint16_t> atomic_uint16_t;
2624typedef atomic< int32_t> atomic_int32_t;
2625typedef atomic<uint32_t> atomic_uint32_t;
2626typedef atomic< int64_t> atomic_int64_t;
2627typedef atomic<uint64_t> atomic_uint64_t;
2628
2629typedef atomic<intptr_t>  atomic_intptr_t;
2630typedef atomic<uintptr_t> atomic_uintptr_t;
2631typedef atomic<size_t>    atomic_size_t;
2632typedef atomic<ptrdiff_t> atomic_ptrdiff_t;
2633typedef atomic<intmax_t>  atomic_intmax_t;
2634typedef atomic<uintmax_t> atomic_uintmax_t;
2635
2636// atomic_*_lock_free : prefer the contention type most highly, then the largest lock-free type
2637
2638#ifdef __cpp_lib_atomic_is_always_lock_free
2639# define _LIBCPP_CONTENTION_LOCK_FREE ::std::__libcpp_is_always_lock_free<__cxx_contention_t>::__value
2640#else
2641# define _LIBCPP_CONTENTION_LOCK_FREE false
2642#endif
2643
2644#if ATOMIC_LLONG_LOCK_FREE == 2
2645typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, long long>::type          __libcpp_signed_lock_free;
2646typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned long long>::type __libcpp_unsigned_lock_free;
2647#elif ATOMIC_INT_LOCK_FREE == 2
2648typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, int>::type                __libcpp_signed_lock_free;
2649typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned int>::type       __libcpp_unsigned_lock_free;
2650#elif ATOMIC_SHORT_LOCK_FREE == 2
2651typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, short>::type              __libcpp_signed_lock_free;
2652typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned short>::type     __libcpp_unsigned_lock_free;
2653#elif ATOMIC_CHAR_LOCK_FREE == 2
2654typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, char>::type               __libcpp_signed_lock_free;
2655typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned char>::type      __libcpp_unsigned_lock_free;
2656#else
2657    // No signed/unsigned lock-free types
2658#define _LIBCPP_NO_LOCK_FREE_TYPES
2659#endif
2660
2661#if !defined(_LIBCPP_NO_LOCK_FREE_TYPES)
2662typedef atomic<__libcpp_signed_lock_free> atomic_signed_lock_free;
2663typedef atomic<__libcpp_unsigned_lock_free> atomic_unsigned_lock_free;
2664#endif
2665
2666#define ATOMIC_FLAG_INIT {false}
2667#define ATOMIC_VAR_INIT(__v) {__v}
2668
2669#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
2670# if defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 1400
2671#  pragma clang deprecated(ATOMIC_VAR_INIT)
2672# endif
2673#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
2674
2675_LIBCPP_END_NAMESPACE_STD
2676
2677#endif // _LIBCPP_ATOMIC
2678