xref: /llvm-project-15.0.7/libcxx/include/atomic (revision f4c1258d)
1// -*- C++ -*-
2//===--------------------------- atomic -----------------------------------===//
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
266template <class T>
267  bool atomic_is_lock_free(const volatile atomic<T>* obj) noexcept;
268
269template <class T>
270  bool atomic_is_lock_free(const atomic<T>* obj) noexcept;
271
272template <class T>
273  void atomic_store(volatile atomic<T>* obj, T desr) noexcept;
274
275template <class T>
276  void atomic_store(atomic<T>* obj, T desr) noexcept;
277
278template <class T>
279  void atomic_store_explicit(volatile atomic<T>* obj, T desr, memory_order m) noexcept;
280
281template <class T>
282  void atomic_store_explicit(atomic<T>* obj, T desr, memory_order m) noexcept;
283
284template <class T>
285  T atomic_load(const volatile atomic<T>* obj) noexcept;
286
287template <class T>
288  T atomic_load(const atomic<T>* obj) noexcept;
289
290template <class T>
291  T atomic_load_explicit(const volatile atomic<T>* obj, memory_order m) noexcept;
292
293template <class T>
294  T atomic_load_explicit(const atomic<T>* obj, memory_order m) noexcept;
295
296template <class T>
297  T atomic_exchange(volatile atomic<T>* obj, T desr) noexcept;
298
299template <class T>
300  T atomic_exchange(atomic<T>* obj, T desr) noexcept;
301
302template <class T>
303  T atomic_exchange_explicit(volatile atomic<T>* obj, T desr, memory_order m) noexcept;
304
305template <class T>
306  T atomic_exchange_explicit(atomic<T>* obj, T desr, memory_order m) noexcept;
307
308template <class T>
309  bool atomic_compare_exchange_weak(volatile atomic<T>* obj, T* expc, T desr) noexcept;
310
311template <class T>
312  bool atomic_compare_exchange_weak(atomic<T>* obj, T* expc, T desr) noexcept;
313
314template <class T>
315  bool atomic_compare_exchange_strong(volatile atomic<T>* obj, T* expc, T desr) noexcept;
316
317template <class T>
318  bool atomic_compare_exchange_strong(atomic<T>* obj, T* expc, T desr) noexcept;
319
320template <class T>
321  bool atomic_compare_exchange_weak_explicit(volatile atomic<T>* obj, T* expc,
322                                             T desr,
323                                             memory_order s, memory_order f) noexcept;
324
325template <class T>
326  bool atomic_compare_exchange_weak_explicit(atomic<T>* obj, T* expc, T desr,
327                                             memory_order s, memory_order f) noexcept;
328
329template <class T>
330  bool atomic_compare_exchange_strong_explicit(volatile atomic<T>* obj,
331                                               T* expc, T desr,
332                                               memory_order s, memory_order f) noexcept;
333
334template <class T>
335  bool atomic_compare_exchange_strong_explicit(atomic<T>* obj, T* expc,
336                                               T desr,
337                                               memory_order s, memory_order f) noexcept;
338
339template <class T>
340  void atomic_wait(const volatile atomic<T>* obj, T old) noexcept;
341
342template <class T>
343  void atomic_wait(const atomic<T>* obj, T old) noexcept;
344
345template <class T>
346  void atomic_wait_explicit(const volatile atomic<T>* obj, T old, memory_order m) noexcept;
347
348template <class T>
349  void atomic_wait_explicit(const atomic<T>* obj, T old, memory_order m) noexcept;
350
351template <class T>
352  void atomic_one(volatile atomic<T>* obj) noexcept;
353
354template <class T>
355  void atomic_one(atomic<T>* obj) noexcept;
356
357template <class T>
358  void atomic_all(volatile atomic<T>* obj) noexcept;
359
360template <class T>
361  void atomic_all(atomic<T>* obj) noexcept;
362
363template <class Integral>
364  Integral atomic_fetch_add(volatile atomic<Integral>* obj, Integral op) noexcept;
365
366template <class Integral>
367  Integral atomic_fetch_add(atomic<Integral>* obj, Integral op) noexcept;
368
369template <class Integral>
370  Integral atomic_fetch_add_explicit(volatile atomic<Integral>* obj, Integral op,
371                              memory_order m) noexcept;
372template <class Integral>
373  Integral atomic_fetch_add_explicit(atomic<Integral>* obj, Integral op,
374                              memory_order m) noexcept;
375template <class Integral>
376  Integral atomic_fetch_sub(volatile atomic<Integral>* obj, Integral op) noexcept;
377
378template <class Integral>
379  Integral atomic_fetch_sub(atomic<Integral>* obj, Integral op) noexcept;
380
381template <class Integral>
382  Integral atomic_fetch_sub_explicit(volatile atomic<Integral>* obj, Integral op,
383                                     memory_order m) noexcept;
384
385template <class Integral>
386  Integral atomic_fetch_sub_explicit(atomic<Integral>* obj, Integral op,
387                                     memory_order m) noexcept;
388
389template <class Integral>
390  Integral atomic_fetch_and(volatile atomic<Integral>* obj, Integral op) noexcept;
391
392template <class Integral>
393  Integral atomic_fetch_and(atomic<Integral>* obj, Integral op) noexcept;
394
395template <class Integral>
396  Integral atomic_fetch_and_explicit(volatile atomic<Integral>* obj, Integral op,
397                                     memory_order m) noexcept;
398
399template <class Integral>
400  Integral atomic_fetch_and_explicit(atomic<Integral>* obj, Integral op,
401                                     memory_order m) noexcept;
402
403template <class Integral>
404  Integral atomic_fetch_or(volatile atomic<Integral>* obj, Integral op) noexcept;
405
406template <class Integral>
407  Integral atomic_fetch_or(atomic<Integral>* obj, Integral op) noexcept;
408
409template <class Integral>
410  Integral atomic_fetch_or_explicit(volatile atomic<Integral>* obj, Integral op,
411                             memory_order m) noexcept;
412
413template <class Integral>
414  Integral atomic_fetch_or_explicit(atomic<Integral>* obj, Integral op,
415                             memory_order m) noexcept;
416
417template <class Integral>
418  Integral atomic_fetch_xor(volatile atomic<Integral>* obj, Integral op) noexcept;
419
420template <class Integral>
421  Integral atomic_fetch_xor(atomic<Integral>* obj, Integral op) noexcept;
422
423template <class Integral>
424  Integral atomic_fetch_xor_explicit(volatile atomic<Integral>* obj, Integral op,
425                                     memory_order m) noexcept;
426
427template <class Integral>
428  Integral atomic_fetch_xor_explicit(atomic<Integral>* obj, Integral op,
429                                     memory_order m) noexcept;
430
431template <class T>
432  T* atomic_fetch_add(volatile atomic<T*>* obj, ptrdiff_t op) noexcept;
433
434template <class T>
435  T* atomic_fetch_add(atomic<T*>* obj, ptrdiff_t op) noexcept;
436
437template <class T>
438  T* atomic_fetch_add_explicit(volatile atomic<T*>* obj, ptrdiff_t op,
439                               memory_order m) noexcept;
440
441template <class T>
442  T* atomic_fetch_add_explicit(atomic<T*>* obj, ptrdiff_t op, memory_order m) noexcept;
443
444template <class T>
445  T* atomic_fetch_sub(volatile atomic<T*>* obj, ptrdiff_t op) noexcept;
446
447template <class T>
448  T* atomic_fetch_sub(atomic<T*>* obj, ptrdiff_t op) noexcept;
449
450template <class T>
451  T* atomic_fetch_sub_explicit(volatile atomic<T*>* obj, ptrdiff_t op,
452                               memory_order m) noexcept;
453
454template <class T>
455  T* atomic_fetch_sub_explicit(atomic<T*>* obj, ptrdiff_t op, memory_order m) noexcept;
456
457// Atomics for standard typedef types
458
459typedef atomic<bool>               atomic_bool;
460typedef atomic<char>               atomic_char;
461typedef atomic<signed char>        atomic_schar;
462typedef atomic<unsigned char>      atomic_uchar;
463typedef atomic<short>              atomic_short;
464typedef atomic<unsigned short>     atomic_ushort;
465typedef atomic<int>                atomic_int;
466typedef atomic<unsigned int>       atomic_uint;
467typedef atomic<long>               atomic_long;
468typedef atomic<unsigned long>      atomic_ulong;
469typedef atomic<long long>          atomic_llong;
470typedef atomic<unsigned long long> atomic_ullong;
471typedef atomic<char8_t>            atomic_char8_t; // C++20
472typedef atomic<char16_t>           atomic_char16_t;
473typedef atomic<char32_t>           atomic_char32_t;
474typedef atomic<wchar_t>            atomic_wchar_t;
475
476typedef atomic<int_least8_t>   atomic_int_least8_t;
477typedef atomic<uint_least8_t>  atomic_uint_least8_t;
478typedef atomic<int_least16_t>  atomic_int_least16_t;
479typedef atomic<uint_least16_t> atomic_uint_least16_t;
480typedef atomic<int_least32_t>  atomic_int_least32_t;
481typedef atomic<uint_least32_t> atomic_uint_least32_t;
482typedef atomic<int_least64_t>  atomic_int_least64_t;
483typedef atomic<uint_least64_t> atomic_uint_least64_t;
484
485typedef atomic<int_fast8_t>   atomic_int_fast8_t;
486typedef atomic<uint_fast8_t>  atomic_uint_fast8_t;
487typedef atomic<int_fast16_t>  atomic_int_fast16_t;
488typedef atomic<uint_fast16_t> atomic_uint_fast16_t;
489typedef atomic<int_fast32_t>  atomic_int_fast32_t;
490typedef atomic<uint_fast32_t> atomic_uint_fast32_t;
491typedef atomic<int_fast64_t>  atomic_int_fast64_t;
492typedef atomic<uint_fast64_t> atomic_uint_fast64_t;
493
494typedef atomic<int8_t>   atomic_int8_t;
495typedef atomic<uint8_t>  atomic_uint8_t;
496typedef atomic<int16_t>  atomic_int16_t;
497typedef atomic<uint16_t> atomic_uint16_t;
498typedef atomic<int32_t>  atomic_int32_t;
499typedef atomic<uint32_t> atomic_uint32_t;
500typedef atomic<int64_t>  atomic_int64_t;
501typedef atomic<uint64_t> atomic_uint64_t;
502
503typedef atomic<intptr_t>  atomic_intptr_t;
504typedef atomic<uintptr_t> atomic_uintptr_t;
505typedef atomic<size_t>    atomic_size_t;
506typedef atomic<ptrdiff_t> atomic_ptrdiff_t;
507typedef atomic<intmax_t>  atomic_intmax_t;
508typedef atomic<uintmax_t> atomic_uintmax_t;
509
510// flag type and operations
511
512typedef struct atomic_flag
513{
514    atomic_flag() noexcept = default; // until C++20
515    constexpr atomic_flag() noexcept; // since C++20
516    atomic_flag(const atomic_flag&) = delete;
517    atomic_flag& operator=(const atomic_flag&) = delete;
518    atomic_flag& operator=(const atomic_flag&) volatile = delete;
519
520    bool test(memory_order m = memory_order_seq_cst) volatile noexcept;
521    bool test(memory_order m = memory_order_seq_cst) noexcept;
522    bool test_and_set(memory_order m = memory_order_seq_cst) volatile noexcept;
523    bool test_and_set(memory_order m = memory_order_seq_cst) noexcept;
524    void clear(memory_order m = memory_order_seq_cst) volatile noexcept;
525    void clear(memory_order m = memory_order_seq_cst) noexcept;
526
527    void wait(bool, memory_order = memory_order::seq_cst) const volatile noexcept;
528    void wait(bool, memory_order = memory_order::seq_cst) const noexcept;
529    void notify_one() volatile noexcept;
530    void notify_one() noexcept;
531    void notify_all() volatile noexcept;
532    void notify_all() noexcept;
533} atomic_flag;
534
535bool atomic_flag_test(volatile atomic_flag* obj) noexcept;
536bool atomic_flag_test(atomic_flag* obj) noexcept;
537bool atomic_flag_test_explicit(volatile atomic_flag* obj,
538                               memory_order m) noexcept;
539bool atomic_flag_test_explicit(atomic_flag* obj, memory_order m) noexcept;
540bool atomic_flag_test_and_set(volatile atomic_flag* obj) noexcept;
541bool atomic_flag_test_and_set(atomic_flag* obj) noexcept;
542bool atomic_flag_test_and_set_explicit(volatile atomic_flag* obj,
543                                       memory_order m) noexcept;
544bool atomic_flag_test_and_set_explicit(atomic_flag* obj, memory_order m) noexcept;
545void atomic_flag_clear(volatile atomic_flag* obj) noexcept;
546void atomic_flag_clear(atomic_flag* obj) noexcept;
547void atomic_flag_clear_explicit(volatile atomic_flag* obj, memory_order m) noexcept;
548void atomic_flag_clear_explicit(atomic_flag* obj, memory_order m) noexcept;
549
550void atomic_wait(const volatile atomic_flag* obj, T old) noexcept;
551void atomic_wait(const atomic_flag* obj, T old) noexcept;
552void atomic_wait_explicit(const volatile atomic_flag* obj, T old, memory_order m) noexcept;
553void atomic_wait_explicit(const atomic_flag* obj, T old, memory_order m) noexcept;
554void atomic_one(volatile atomic_flag* obj) noexcept;
555void atomic_one(atomic_flag* obj) noexcept;
556void atomic_all(volatile atomic_flag* obj) noexcept;
557void atomic_all(atomic_flag* obj) noexcept;
558
559// fences
560
561void atomic_thread_fence(memory_order m) noexcept;
562void atomic_signal_fence(memory_order m) noexcept;
563
564// deprecated
565
566template <class T>
567  void atomic_init(volatile atomic<T>* obj, typename atomic<T>::value_type desr) noexcept;
568
569template <class T>
570  void atomic_init(atomic<T>* obj, typename atomic<T>::value_type desr) noexcept;
571
572#define ATOMIC_VAR_INIT(value) see below
573
574#define ATOMIC_FLAG_INIT see below
575
576}  // std
577
578*/
579
580#include <__availability>
581#include <__config>
582#include <__threading_support>
583#include <cstddef>
584#include <cstdint>
585#include <cstring>
586#include <type_traits>
587#include <version>
588
589#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
590#pragma GCC system_header
591#endif
592
593#ifdef _LIBCPP_HAS_NO_THREADS
594# error <atomic> is not supported on this single threaded system
595#endif
596#ifdef _LIBCPP_HAS_NO_ATOMIC_HEADER
597# error <atomic> is not implemented
598#endif
599#ifdef kill_dependency
600# error C++ standard library is incompatible with <stdatomic.h>
601#endif
602
603#define _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m) \
604  _LIBCPP_DIAGNOSE_WARNING(__m == memory_order_consume || \
605                           __m == memory_order_acquire || \
606                           __m == memory_order_acq_rel,   \
607                        "memory order argument to atomic operation is invalid")
608
609#define _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m) \
610  _LIBCPP_DIAGNOSE_WARNING(__m == memory_order_release || \
611                           __m == memory_order_acq_rel,   \
612                        "memory order argument to atomic operation is invalid")
613
614#define _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__m, __f) \
615  _LIBCPP_DIAGNOSE_WARNING(__f == memory_order_release || \
616                           __f == memory_order_acq_rel,   \
617                        "memory order argument to atomic operation is invalid")
618
619_LIBCPP_BEGIN_NAMESPACE_STD
620
621// Figure out what the underlying type for `memory_order` would be if it were
622// declared as an unscoped enum (accounting for -fshort-enums). Use this result
623// to pin the underlying type in C++20.
624enum __legacy_memory_order {
625    __mo_relaxed,
626    __mo_consume,
627    __mo_acquire,
628    __mo_release,
629    __mo_acq_rel,
630    __mo_seq_cst
631};
632
633typedef underlying_type<__legacy_memory_order>::type __memory_order_underlying_t;
634
635#if _LIBCPP_STD_VER > 17
636
637enum class memory_order : __memory_order_underlying_t {
638  relaxed = __mo_relaxed,
639  consume = __mo_consume,
640  acquire = __mo_acquire,
641  release = __mo_release,
642  acq_rel = __mo_acq_rel,
643  seq_cst = __mo_seq_cst
644};
645
646inline constexpr auto memory_order_relaxed = memory_order::relaxed;
647inline constexpr auto memory_order_consume = memory_order::consume;
648inline constexpr auto memory_order_acquire = memory_order::acquire;
649inline constexpr auto memory_order_release = memory_order::release;
650inline constexpr auto memory_order_acq_rel = memory_order::acq_rel;
651inline constexpr auto memory_order_seq_cst = memory_order::seq_cst;
652
653#else
654
655typedef enum memory_order {
656  memory_order_relaxed = __mo_relaxed,
657  memory_order_consume = __mo_consume,
658  memory_order_acquire = __mo_acquire,
659  memory_order_release = __mo_release,
660  memory_order_acq_rel = __mo_acq_rel,
661  memory_order_seq_cst = __mo_seq_cst,
662} memory_order;
663
664#endif // _LIBCPP_STD_VER > 17
665
666template <typename _Tp> _LIBCPP_INLINE_VISIBILITY
667bool __cxx_nonatomic_compare_equal(_Tp const& __lhs, _Tp const& __rhs) {
668    return _VSTD::memcmp(&__lhs, &__rhs, sizeof(_Tp)) == 0;
669}
670
671static_assert((is_same<underlying_type<memory_order>::type, __memory_order_underlying_t>::value),
672  "unexpected underlying type for std::memory_order");
673
674#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP) || \
675    defined(_LIBCPP_ATOMIC_ONLY_USE_BUILTINS)
676
677// [atomics.types.generic]p1 guarantees _Tp is trivially copyable. Because
678// the default operator= in an object is not volatile, a byte-by-byte copy
679// is required.
680template <typename _Tp, typename _Tv> _LIBCPP_INLINE_VISIBILITY
681typename enable_if<is_assignable<_Tp&, _Tv>::value>::type
682__cxx_atomic_assign_volatile(_Tp& __a_value, _Tv const& __val) {
683  __a_value = __val;
684}
685template <typename _Tp, typename _Tv> _LIBCPP_INLINE_VISIBILITY
686typename enable_if<is_assignable<_Tp&, _Tv>::value>::type
687__cxx_atomic_assign_volatile(_Tp volatile& __a_value, _Tv volatile const& __val) {
688  volatile char* __to = reinterpret_cast<volatile char*>(&__a_value);
689  volatile char* __end = __to + sizeof(_Tp);
690  volatile const char* __from = reinterpret_cast<volatile const char*>(&__val);
691  while (__to != __end)
692    *__to++ = *__from++;
693}
694
695#endif
696
697#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP)
698
699template <typename _Tp>
700struct __cxx_atomic_base_impl {
701
702  _LIBCPP_INLINE_VISIBILITY
703#ifndef _LIBCPP_CXX03_LANG
704    __cxx_atomic_base_impl() _NOEXCEPT = default;
705#else
706    __cxx_atomic_base_impl() _NOEXCEPT : __a_value() {}
707#endif // _LIBCPP_CXX03_LANG
708  _LIBCPP_CONSTEXPR explicit __cxx_atomic_base_impl(_Tp value) _NOEXCEPT
709    : __a_value(value) {}
710  _Tp __a_value;
711};
712
713_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR int __to_gcc_order(memory_order __order) {
714  // Avoid switch statement to make this a constexpr.
715  return __order == memory_order_relaxed ? __ATOMIC_RELAXED:
716         (__order == memory_order_acquire ? __ATOMIC_ACQUIRE:
717          (__order == memory_order_release ? __ATOMIC_RELEASE:
718           (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST:
719            (__order == memory_order_acq_rel ? __ATOMIC_ACQ_REL:
720              __ATOMIC_CONSUME))));
721}
722
723_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR int __to_gcc_failure_order(memory_order __order) {
724  // Avoid switch statement to make this a constexpr.
725  return __order == memory_order_relaxed ? __ATOMIC_RELAXED:
726         (__order == memory_order_acquire ? __ATOMIC_ACQUIRE:
727          (__order == memory_order_release ? __ATOMIC_RELAXED:
728           (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST:
729            (__order == memory_order_acq_rel ? __ATOMIC_ACQUIRE:
730              __ATOMIC_CONSUME))));
731}
732
733template <typename _Tp>
734_LIBCPP_INLINE_VISIBILITY
735void __cxx_atomic_init(volatile __cxx_atomic_base_impl<_Tp>* __a,  _Tp __val) {
736  __cxx_atomic_assign_volatile(__a->__a_value, __val);
737}
738
739template <typename _Tp>
740_LIBCPP_INLINE_VISIBILITY
741void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp>* __a,  _Tp __val) {
742  __a->__a_value = __val;
743}
744
745_LIBCPP_INLINE_VISIBILITY inline
746void __cxx_atomic_thread_fence(memory_order __order) {
747  __atomic_thread_fence(__to_gcc_order(__order));
748}
749
750_LIBCPP_INLINE_VISIBILITY inline
751void __cxx_atomic_signal_fence(memory_order __order) {
752  __atomic_signal_fence(__to_gcc_order(__order));
753}
754
755template <typename _Tp>
756_LIBCPP_INLINE_VISIBILITY
757void __cxx_atomic_store(volatile __cxx_atomic_base_impl<_Tp>* __a,  _Tp __val,
758                        memory_order __order) {
759  __atomic_store(&__a->__a_value, &__val,
760                 __to_gcc_order(__order));
761}
762
763template <typename _Tp>
764_LIBCPP_INLINE_VISIBILITY
765void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp>* __a,  _Tp __val,
766                        memory_order __order) {
767  __atomic_store(&__a->__a_value, &__val,
768                 __to_gcc_order(__order));
769}
770
771template <typename _Tp>
772_LIBCPP_INLINE_VISIBILITY
773_Tp __cxx_atomic_load(const volatile __cxx_atomic_base_impl<_Tp>* __a,
774                      memory_order __order) {
775  _Tp __ret;
776  __atomic_load(&__a->__a_value, &__ret,
777                __to_gcc_order(__order));
778  return __ret;
779}
780
781template <typename _Tp>
782_LIBCPP_INLINE_VISIBILITY
783_Tp __cxx_atomic_load(const __cxx_atomic_base_impl<_Tp>* __a, memory_order __order) {
784  _Tp __ret;
785  __atomic_load(&__a->__a_value, &__ret,
786                __to_gcc_order(__order));
787  return __ret;
788}
789
790template <typename _Tp>
791_LIBCPP_INLINE_VISIBILITY
792_Tp __cxx_atomic_exchange(volatile __cxx_atomic_base_impl<_Tp>* __a,
793                          _Tp __value, memory_order __order) {
794  _Tp __ret;
795  __atomic_exchange(&__a->__a_value, &__value, &__ret,
796                    __to_gcc_order(__order));
797  return __ret;
798}
799
800template <typename _Tp>
801_LIBCPP_INLINE_VISIBILITY
802_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp>* __a, _Tp __value,
803                          memory_order __order) {
804  _Tp __ret;
805  __atomic_exchange(&__a->__a_value, &__value, &__ret,
806                    __to_gcc_order(__order));
807  return __ret;
808}
809
810template <typename _Tp>
811_LIBCPP_INLINE_VISIBILITY
812bool __cxx_atomic_compare_exchange_strong(
813    volatile __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value,
814    memory_order __success, memory_order __failure) {
815  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
816                                   false,
817                                   __to_gcc_order(__success),
818                                   __to_gcc_failure_order(__failure));
819}
820
821template <typename _Tp>
822_LIBCPP_INLINE_VISIBILITY
823bool __cxx_atomic_compare_exchange_strong(
824    __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success,
825    memory_order __failure) {
826  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
827                                   false,
828                                   __to_gcc_order(__success),
829                                   __to_gcc_failure_order(__failure));
830}
831
832template <typename _Tp>
833_LIBCPP_INLINE_VISIBILITY
834bool __cxx_atomic_compare_exchange_weak(
835    volatile __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value,
836    memory_order __success, memory_order __failure) {
837  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
838                                   true,
839                                   __to_gcc_order(__success),
840                                   __to_gcc_failure_order(__failure));
841}
842
843template <typename _Tp>
844_LIBCPP_INLINE_VISIBILITY
845bool __cxx_atomic_compare_exchange_weak(
846    __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success,
847    memory_order __failure) {
848  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
849                                   true,
850                                   __to_gcc_order(__success),
851                                   __to_gcc_failure_order(__failure));
852}
853
854template <typename _Tp>
855struct __skip_amt { enum {value = 1}; };
856
857template <typename _Tp>
858struct __skip_amt<_Tp*> { enum {value = sizeof(_Tp)}; };
859
860// FIXME: Haven't figured out what the spec says about using arrays with
861// atomic_fetch_add. Force a failure rather than creating bad behavior.
862template <typename _Tp>
863struct __skip_amt<_Tp[]> { };
864template <typename _Tp, int n>
865struct __skip_amt<_Tp[n]> { };
866
867template <typename _Tp, typename _Td>
868_LIBCPP_INLINE_VISIBILITY
869_Tp __cxx_atomic_fetch_add(volatile __cxx_atomic_base_impl<_Tp>* __a,
870                           _Td __delta, memory_order __order) {
871  return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
872                            __to_gcc_order(__order));
873}
874
875template <typename _Tp, typename _Td>
876_LIBCPP_INLINE_VISIBILITY
877_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp>* __a, _Td __delta,
878                           memory_order __order) {
879  return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
880                            __to_gcc_order(__order));
881}
882
883template <typename _Tp, typename _Td>
884_LIBCPP_INLINE_VISIBILITY
885_Tp __cxx_atomic_fetch_sub(volatile __cxx_atomic_base_impl<_Tp>* __a,
886                           _Td __delta, memory_order __order) {
887  return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
888                            __to_gcc_order(__order));
889}
890
891template <typename _Tp, typename _Td>
892_LIBCPP_INLINE_VISIBILITY
893_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp>* __a, _Td __delta,
894                           memory_order __order) {
895  return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
896                            __to_gcc_order(__order));
897}
898
899template <typename _Tp>
900_LIBCPP_INLINE_VISIBILITY
901_Tp __cxx_atomic_fetch_and(volatile __cxx_atomic_base_impl<_Tp>* __a,
902                           _Tp __pattern, memory_order __order) {
903  return __atomic_fetch_and(&__a->__a_value, __pattern,
904                            __to_gcc_order(__order));
905}
906
907template <typename _Tp>
908_LIBCPP_INLINE_VISIBILITY
909_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp>* __a,
910                           _Tp __pattern, memory_order __order) {
911  return __atomic_fetch_and(&__a->__a_value, __pattern,
912                            __to_gcc_order(__order));
913}
914
915template <typename _Tp>
916_LIBCPP_INLINE_VISIBILITY
917_Tp __cxx_atomic_fetch_or(volatile __cxx_atomic_base_impl<_Tp>* __a,
918                          _Tp __pattern, memory_order __order) {
919  return __atomic_fetch_or(&__a->__a_value, __pattern,
920                           __to_gcc_order(__order));
921}
922
923template <typename _Tp>
924_LIBCPP_INLINE_VISIBILITY
925_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp>* __a, _Tp __pattern,
926                          memory_order __order) {
927  return __atomic_fetch_or(&__a->__a_value, __pattern,
928                           __to_gcc_order(__order));
929}
930
931template <typename _Tp>
932_LIBCPP_INLINE_VISIBILITY
933_Tp __cxx_atomic_fetch_xor(volatile __cxx_atomic_base_impl<_Tp>* __a,
934                           _Tp __pattern, memory_order __order) {
935  return __atomic_fetch_xor(&__a->__a_value, __pattern,
936                            __to_gcc_order(__order));
937}
938
939template <typename _Tp>
940_LIBCPP_INLINE_VISIBILITY
941_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp>* __a, _Tp __pattern,
942                           memory_order __order) {
943  return __atomic_fetch_xor(&__a->__a_value, __pattern,
944                            __to_gcc_order(__order));
945}
946
947#define __cxx_atomic_is_lock_free(__s) __atomic_is_lock_free(__s, 0)
948
949#elif defined(_LIBCPP_HAS_C_ATOMIC_IMP)
950
951template <typename _Tp>
952struct __cxx_atomic_base_impl {
953
954  _LIBCPP_INLINE_VISIBILITY
955#ifndef _LIBCPP_CXX03_LANG
956    __cxx_atomic_base_impl() _NOEXCEPT = default;
957#else
958    __cxx_atomic_base_impl() _NOEXCEPT : __a_value() {}
959#endif // _LIBCPP_CXX03_LANG
960  _LIBCPP_CONSTEXPR explicit __cxx_atomic_base_impl(_Tp value) _NOEXCEPT
961    : __a_value(value) {}
962  _LIBCPP_DISABLE_EXTENSION_WARNING _Atomic(_Tp) __a_value;
963};
964
965#define __cxx_atomic_is_lock_free(__s) __c11_atomic_is_lock_free(__s)
966
967_LIBCPP_INLINE_VISIBILITY inline
968void __cxx_atomic_thread_fence(memory_order __order) _NOEXCEPT {
969    __c11_atomic_thread_fence(static_cast<__memory_order_underlying_t>(__order));
970}
971
972_LIBCPP_INLINE_VISIBILITY inline
973void __cxx_atomic_signal_fence(memory_order __order) _NOEXCEPT {
974    __c11_atomic_signal_fence(static_cast<__memory_order_underlying_t>(__order));
975}
976
977template<class _Tp>
978_LIBCPP_INLINE_VISIBILITY
979void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __val) _NOEXCEPT {
980    __c11_atomic_init(&__a->__a_value, __val);
981}
982template<class _Tp>
983_LIBCPP_INLINE_VISIBILITY
984void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp> * __a, _Tp __val) _NOEXCEPT {
985    __c11_atomic_init(&__a->__a_value, __val);
986}
987
988template<class _Tp>
989_LIBCPP_INLINE_VISIBILITY
990void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __val, memory_order __order) _NOEXCEPT {
991    __c11_atomic_store(&__a->__a_value, __val, static_cast<__memory_order_underlying_t>(__order));
992}
993template<class _Tp>
994_LIBCPP_INLINE_VISIBILITY
995void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp> * __a, _Tp __val, memory_order __order) _NOEXCEPT {
996    __c11_atomic_store(&__a->__a_value, __val, static_cast<__memory_order_underlying_t>(__order));
997}
998
999template<class _Tp>
1000_LIBCPP_INLINE_VISIBILITY
1001_Tp __cxx_atomic_load(__cxx_atomic_base_impl<_Tp> const volatile* __a, memory_order __order) _NOEXCEPT {
1002    using __ptr_type = typename remove_const<decltype(__a->__a_value)>::type*;
1003    return __c11_atomic_load(const_cast<__ptr_type>(&__a->__a_value), static_cast<__memory_order_underlying_t>(__order));
1004}
1005template<class _Tp>
1006_LIBCPP_INLINE_VISIBILITY
1007_Tp __cxx_atomic_load(__cxx_atomic_base_impl<_Tp> const* __a, memory_order __order) _NOEXCEPT {
1008    using __ptr_type = typename remove_const<decltype(__a->__a_value)>::type*;
1009    return __c11_atomic_load(const_cast<__ptr_type>(&__a->__a_value), static_cast<__memory_order_underlying_t>(__order));
1010}
1011
1012template<class _Tp>
1013_LIBCPP_INLINE_VISIBILITY
1014_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __value, memory_order __order) _NOEXCEPT {
1015    return __c11_atomic_exchange(&__a->__a_value, __value, static_cast<__memory_order_underlying_t>(__order));
1016}
1017template<class _Tp>
1018_LIBCPP_INLINE_VISIBILITY
1019_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp> * __a, _Tp __value, memory_order __order) _NOEXCEPT {
1020    return __c11_atomic_exchange(&__a->__a_value, __value, static_cast<__memory_order_underlying_t>(__order));
1021}
1022
1023_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR memory_order __to_failure_order(memory_order __order) {
1024  // Avoid switch statement to make this a constexpr.
1025  return __order == memory_order_release ? memory_order_relaxed:
1026         (__order == memory_order_acq_rel ? memory_order_acquire:
1027             __order);
1028}
1029
1030template<class _Tp>
1031_LIBCPP_INLINE_VISIBILITY
1032bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
1033    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)));
1034}
1035template<class _Tp>
1036_LIBCPP_INLINE_VISIBILITY
1037bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_base_impl<_Tp> * __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
1038    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)));
1039}
1040
1041template<class _Tp>
1042_LIBCPP_INLINE_VISIBILITY
1043bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
1044    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)));
1045}
1046template<class _Tp>
1047_LIBCPP_INLINE_VISIBILITY
1048bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_base_impl<_Tp> * __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
1049    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)));
1050}
1051
1052template<class _Tp>
1053_LIBCPP_INLINE_VISIBILITY
1054_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __delta, memory_order __order) _NOEXCEPT {
1055    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1056}
1057template<class _Tp>
1058_LIBCPP_INLINE_VISIBILITY
1059_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp> * __a, _Tp __delta, memory_order __order) _NOEXCEPT {
1060    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1061}
1062
1063template<class _Tp>
1064_LIBCPP_INLINE_VISIBILITY
1065_Tp* __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
1066    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1067}
1068template<class _Tp>
1069_LIBCPP_INLINE_VISIBILITY
1070_Tp* __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp*> * __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
1071    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1072}
1073
1074template<class _Tp>
1075_LIBCPP_INLINE_VISIBILITY
1076_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __delta, memory_order __order) _NOEXCEPT {
1077    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1078}
1079template<class _Tp>
1080_LIBCPP_INLINE_VISIBILITY
1081_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp> * __a, _Tp __delta, memory_order __order) _NOEXCEPT {
1082    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1083}
1084template<class _Tp>
1085_LIBCPP_INLINE_VISIBILITY
1086_Tp* __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
1087    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1088}
1089template<class _Tp>
1090_LIBCPP_INLINE_VISIBILITY
1091_Tp* __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp*> * __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
1092    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
1093}
1094
1095template<class _Tp>
1096_LIBCPP_INLINE_VISIBILITY
1097_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1098    return __c11_atomic_fetch_and(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1099}
1100template<class _Tp>
1101_LIBCPP_INLINE_VISIBILITY
1102_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1103    return __c11_atomic_fetch_and(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1104}
1105
1106template<class _Tp>
1107_LIBCPP_INLINE_VISIBILITY
1108_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1109    return __c11_atomic_fetch_or(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1110}
1111template<class _Tp>
1112_LIBCPP_INLINE_VISIBILITY
1113_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1114    return __c11_atomic_fetch_or(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1115}
1116
1117template<class _Tp>
1118_LIBCPP_INLINE_VISIBILITY
1119_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1120    return __c11_atomic_fetch_xor(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1121}
1122template<class _Tp>
1123_LIBCPP_INLINE_VISIBILITY
1124_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
1125    return __c11_atomic_fetch_xor(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
1126}
1127
1128#endif // _LIBCPP_HAS_GCC_ATOMIC_IMP, _LIBCPP_HAS_C_ATOMIC_IMP
1129
1130template <class _Tp>
1131_LIBCPP_INLINE_VISIBILITY
1132_Tp kill_dependency(_Tp __y) _NOEXCEPT
1133{
1134    return __y;
1135}
1136
1137#if defined(__CLANG_ATOMIC_BOOL_LOCK_FREE)
1138# define ATOMIC_BOOL_LOCK_FREE      __CLANG_ATOMIC_BOOL_LOCK_FREE
1139# define ATOMIC_CHAR_LOCK_FREE      __CLANG_ATOMIC_CHAR_LOCK_FREE
1140#ifndef _LIBCPP_HAS_NO_CHAR8_T
1141# define ATOMIC_CHAR8_T_LOCK_FREE   __CLANG_ATOMIC_CHAR8_T_LOCK_FREE
1142#endif
1143# define ATOMIC_CHAR16_T_LOCK_FREE  __CLANG_ATOMIC_CHAR16_T_LOCK_FREE
1144# define ATOMIC_CHAR32_T_LOCK_FREE  __CLANG_ATOMIC_CHAR32_T_LOCK_FREE
1145# define ATOMIC_WCHAR_T_LOCK_FREE   __CLANG_ATOMIC_WCHAR_T_LOCK_FREE
1146# define ATOMIC_SHORT_LOCK_FREE     __CLANG_ATOMIC_SHORT_LOCK_FREE
1147# define ATOMIC_INT_LOCK_FREE       __CLANG_ATOMIC_INT_LOCK_FREE
1148# define ATOMIC_LONG_LOCK_FREE      __CLANG_ATOMIC_LONG_LOCK_FREE
1149# define ATOMIC_LLONG_LOCK_FREE     __CLANG_ATOMIC_LLONG_LOCK_FREE
1150# define ATOMIC_POINTER_LOCK_FREE   __CLANG_ATOMIC_POINTER_LOCK_FREE
1151#elif defined(__GCC_ATOMIC_BOOL_LOCK_FREE)
1152# define ATOMIC_BOOL_LOCK_FREE      __GCC_ATOMIC_BOOL_LOCK_FREE
1153# define ATOMIC_CHAR_LOCK_FREE      __GCC_ATOMIC_CHAR_LOCK_FREE
1154#ifndef _LIBCPP_HAS_NO_CHAR8_T
1155# define ATOMIC_CHAR8_T_LOCK_FREE   __GCC_ATOMIC_CHAR8_T_LOCK_FREE
1156#endif
1157# define ATOMIC_CHAR16_T_LOCK_FREE  __GCC_ATOMIC_CHAR16_T_LOCK_FREE
1158# define ATOMIC_CHAR32_T_LOCK_FREE  __GCC_ATOMIC_CHAR32_T_LOCK_FREE
1159# define ATOMIC_WCHAR_T_LOCK_FREE   __GCC_ATOMIC_WCHAR_T_LOCK_FREE
1160# define ATOMIC_SHORT_LOCK_FREE     __GCC_ATOMIC_SHORT_LOCK_FREE
1161# define ATOMIC_INT_LOCK_FREE       __GCC_ATOMIC_INT_LOCK_FREE
1162# define ATOMIC_LONG_LOCK_FREE      __GCC_ATOMIC_LONG_LOCK_FREE
1163# define ATOMIC_LLONG_LOCK_FREE     __GCC_ATOMIC_LLONG_LOCK_FREE
1164# define ATOMIC_POINTER_LOCK_FREE   __GCC_ATOMIC_POINTER_LOCK_FREE
1165#endif
1166
1167#ifdef _LIBCPP_ATOMIC_ONLY_USE_BUILTINS
1168
1169template<typename _Tp>
1170struct __cxx_atomic_lock_impl {
1171
1172  _LIBCPP_INLINE_VISIBILITY
1173  __cxx_atomic_lock_impl() _NOEXCEPT
1174    : __a_value(), __a_lock(0) {}
1175  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR explicit
1176  __cxx_atomic_lock_impl(_Tp value) _NOEXCEPT
1177    : __a_value(value), __a_lock(0) {}
1178
1179  _Tp __a_value;
1180  mutable __cxx_atomic_base_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_lock;
1181
1182  _LIBCPP_INLINE_VISIBILITY void __lock() const volatile {
1183    while(1 == __cxx_atomic_exchange(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(true), memory_order_acquire))
1184        /*spin*/;
1185  }
1186  _LIBCPP_INLINE_VISIBILITY void __lock() const {
1187    while(1 == __cxx_atomic_exchange(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(true), memory_order_acquire))
1188        /*spin*/;
1189  }
1190  _LIBCPP_INLINE_VISIBILITY void __unlock() const volatile {
1191    __cxx_atomic_store(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(false), memory_order_release);
1192  }
1193  _LIBCPP_INLINE_VISIBILITY void __unlock() const {
1194    __cxx_atomic_store(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(false), memory_order_release);
1195  }
1196  _LIBCPP_INLINE_VISIBILITY _Tp __read() const volatile {
1197    __lock();
1198    _Tp __old;
1199    __cxx_atomic_assign_volatile(__old, __a_value);
1200    __unlock();
1201    return __old;
1202  }
1203  _LIBCPP_INLINE_VISIBILITY _Tp __read() const {
1204    __lock();
1205    _Tp __old = __a_value;
1206    __unlock();
1207    return __old;
1208  }
1209};
1210
1211template <typename _Tp>
1212_LIBCPP_INLINE_VISIBILITY
1213void __cxx_atomic_init(volatile __cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val) {
1214  __cxx_atomic_assign_volatile(__a->__a_value, __val);
1215}
1216template <typename _Tp>
1217_LIBCPP_INLINE_VISIBILITY
1218void __cxx_atomic_init(__cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val) {
1219  __a->__a_value = __val;
1220}
1221
1222template <typename _Tp>
1223_LIBCPP_INLINE_VISIBILITY
1224void __cxx_atomic_store(volatile __cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val, memory_order) {
1225  __a->__lock();
1226  __cxx_atomic_assign_volatile(__a->__a_value, __val);
1227  __a->__unlock();
1228}
1229template <typename _Tp>
1230_LIBCPP_INLINE_VISIBILITY
1231void __cxx_atomic_store(__cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val, memory_order) {
1232  __a->__lock();
1233  __a->__a_value = __val;
1234  __a->__unlock();
1235}
1236
1237template <typename _Tp>
1238_LIBCPP_INLINE_VISIBILITY
1239_Tp __cxx_atomic_load(const volatile __cxx_atomic_lock_impl<_Tp>* __a, memory_order) {
1240  return __a->__read();
1241}
1242template <typename _Tp>
1243_LIBCPP_INLINE_VISIBILITY
1244_Tp __cxx_atomic_load(const __cxx_atomic_lock_impl<_Tp>* __a, memory_order) {
1245  return __a->__read();
1246}
1247
1248template <typename _Tp>
1249_LIBCPP_INLINE_VISIBILITY
1250_Tp __cxx_atomic_exchange(volatile __cxx_atomic_lock_impl<_Tp>* __a, _Tp __value, memory_order) {
1251  __a->__lock();
1252  _Tp __old;
1253  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1254  __cxx_atomic_assign_volatile(__a->__a_value, __value);
1255  __a->__unlock();
1256  return __old;
1257}
1258template <typename _Tp>
1259_LIBCPP_INLINE_VISIBILITY
1260_Tp __cxx_atomic_exchange(__cxx_atomic_lock_impl<_Tp>* __a, _Tp __value, memory_order) {
1261  __a->__lock();
1262  _Tp __old = __a->__a_value;
1263  __a->__a_value = __value;
1264  __a->__unlock();
1265  return __old;
1266}
1267
1268template <typename _Tp>
1269_LIBCPP_INLINE_VISIBILITY
1270bool __cxx_atomic_compare_exchange_strong(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1271                                          _Tp* __expected, _Tp __value, memory_order, memory_order) {
1272  _Tp __temp;
1273  __a->__lock();
1274  __cxx_atomic_assign_volatile(__temp, __a->__a_value);
1275  bool __ret = (_VSTD::memcmp(&__temp, __expected, sizeof(_Tp)) == 0);
1276  if(__ret)
1277    __cxx_atomic_assign_volatile(__a->__a_value, __value);
1278  else
1279    __cxx_atomic_assign_volatile(*__expected, __a->__a_value);
1280  __a->__unlock();
1281  return __ret;
1282}
1283template <typename _Tp>
1284_LIBCPP_INLINE_VISIBILITY
1285bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_lock_impl<_Tp>* __a,
1286                                          _Tp* __expected, _Tp __value, memory_order, memory_order) {
1287  __a->__lock();
1288  bool __ret = (_VSTD::memcmp(&__a->__a_value, __expected, sizeof(_Tp)) == 0);
1289  if(__ret)
1290    _VSTD::memcpy(&__a->__a_value, &__value, sizeof(_Tp));
1291  else
1292    _VSTD::memcpy(__expected, &__a->__a_value, sizeof(_Tp));
1293  __a->__unlock();
1294  return __ret;
1295}
1296
1297template <typename _Tp>
1298_LIBCPP_INLINE_VISIBILITY
1299bool __cxx_atomic_compare_exchange_weak(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1300                                        _Tp* __expected, _Tp __value, memory_order, memory_order) {
1301  _Tp __temp;
1302  __a->__lock();
1303  __cxx_atomic_assign_volatile(__temp, __a->__a_value);
1304  bool __ret = (_VSTD::memcmp(&__temp, __expected, sizeof(_Tp)) == 0);
1305  if(__ret)
1306    __cxx_atomic_assign_volatile(__a->__a_value, __value);
1307  else
1308    __cxx_atomic_assign_volatile(*__expected, __a->__a_value);
1309  __a->__unlock();
1310  return __ret;
1311}
1312template <typename _Tp>
1313_LIBCPP_INLINE_VISIBILITY
1314bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_lock_impl<_Tp>* __a,
1315                                        _Tp* __expected, _Tp __value, memory_order, memory_order) {
1316  __a->__lock();
1317  bool __ret = (_VSTD::memcmp(&__a->__a_value, __expected, sizeof(_Tp)) == 0);
1318  if(__ret)
1319    _VSTD::memcpy(&__a->__a_value, &__value, sizeof(_Tp));
1320  else
1321    _VSTD::memcpy(__expected, &__a->__a_value, sizeof(_Tp));
1322  __a->__unlock();
1323  return __ret;
1324}
1325
1326template <typename _Tp, typename _Td>
1327_LIBCPP_INLINE_VISIBILITY
1328_Tp __cxx_atomic_fetch_add(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1329                           _Td __delta, memory_order) {
1330  __a->__lock();
1331  _Tp __old;
1332  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1333  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old + __delta));
1334  __a->__unlock();
1335  return __old;
1336}
1337template <typename _Tp, typename _Td>
1338_LIBCPP_INLINE_VISIBILITY
1339_Tp __cxx_atomic_fetch_add(__cxx_atomic_lock_impl<_Tp>* __a,
1340                           _Td __delta, memory_order) {
1341  __a->__lock();
1342  _Tp __old = __a->__a_value;
1343  __a->__a_value += __delta;
1344  __a->__unlock();
1345  return __old;
1346}
1347
1348template <typename _Tp, typename _Td>
1349_LIBCPP_INLINE_VISIBILITY
1350_Tp* __cxx_atomic_fetch_add(volatile __cxx_atomic_lock_impl<_Tp*>* __a,
1351                           ptrdiff_t __delta, memory_order) {
1352  __a->__lock();
1353  _Tp* __old;
1354  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1355  __cxx_atomic_assign_volatile(__a->__a_value, __old + __delta);
1356  __a->__unlock();
1357  return __old;
1358}
1359template <typename _Tp, typename _Td>
1360_LIBCPP_INLINE_VISIBILITY
1361_Tp* __cxx_atomic_fetch_add(__cxx_atomic_lock_impl<_Tp*>* __a,
1362                           ptrdiff_t __delta, memory_order) {
1363  __a->__lock();
1364  _Tp* __old = __a->__a_value;
1365  __a->__a_value += __delta;
1366  __a->__unlock();
1367  return __old;
1368}
1369
1370template <typename _Tp, typename _Td>
1371_LIBCPP_INLINE_VISIBILITY
1372_Tp __cxx_atomic_fetch_sub(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1373                           _Td __delta, memory_order) {
1374  __a->__lock();
1375  _Tp __old;
1376  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1377  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old - __delta));
1378  __a->__unlock();
1379  return __old;
1380}
1381template <typename _Tp, typename _Td>
1382_LIBCPP_INLINE_VISIBILITY
1383_Tp __cxx_atomic_fetch_sub(__cxx_atomic_lock_impl<_Tp>* __a,
1384                           _Td __delta, memory_order) {
1385  __a->__lock();
1386  _Tp __old = __a->__a_value;
1387  __a->__a_value -= __delta;
1388  __a->__unlock();
1389  return __old;
1390}
1391
1392template <typename _Tp>
1393_LIBCPP_INLINE_VISIBILITY
1394_Tp __cxx_atomic_fetch_and(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1395                           _Tp __pattern, memory_order) {
1396  __a->__lock();
1397  _Tp __old;
1398  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1399  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old & __pattern));
1400  __a->__unlock();
1401  return __old;
1402}
1403template <typename _Tp>
1404_LIBCPP_INLINE_VISIBILITY
1405_Tp __cxx_atomic_fetch_and(__cxx_atomic_lock_impl<_Tp>* __a,
1406                           _Tp __pattern, memory_order) {
1407  __a->__lock();
1408  _Tp __old = __a->__a_value;
1409  __a->__a_value &= __pattern;
1410  __a->__unlock();
1411  return __old;
1412}
1413
1414template <typename _Tp>
1415_LIBCPP_INLINE_VISIBILITY
1416_Tp __cxx_atomic_fetch_or(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1417                          _Tp __pattern, memory_order) {
1418  __a->__lock();
1419  _Tp __old;
1420  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1421  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old | __pattern));
1422  __a->__unlock();
1423  return __old;
1424}
1425template <typename _Tp>
1426_LIBCPP_INLINE_VISIBILITY
1427_Tp __cxx_atomic_fetch_or(__cxx_atomic_lock_impl<_Tp>* __a,
1428                          _Tp __pattern, memory_order) {
1429  __a->__lock();
1430  _Tp __old = __a->__a_value;
1431  __a->__a_value |= __pattern;
1432  __a->__unlock();
1433  return __old;
1434}
1435
1436template <typename _Tp>
1437_LIBCPP_INLINE_VISIBILITY
1438_Tp __cxx_atomic_fetch_xor(volatile __cxx_atomic_lock_impl<_Tp>* __a,
1439                           _Tp __pattern, memory_order) {
1440  __a->__lock();
1441  _Tp __old;
1442  __cxx_atomic_assign_volatile(__old, __a->__a_value);
1443  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old ^ __pattern));
1444  __a->__unlock();
1445  return __old;
1446}
1447template <typename _Tp>
1448_LIBCPP_INLINE_VISIBILITY
1449_Tp __cxx_atomic_fetch_xor(__cxx_atomic_lock_impl<_Tp>* __a,
1450                           _Tp __pattern, memory_order) {
1451  __a->__lock();
1452  _Tp __old = __a->__a_value;
1453  __a->__a_value ^= __pattern;
1454  __a->__unlock();
1455  return __old;
1456}
1457
1458#ifdef __cpp_lib_atomic_is_always_lock_free
1459
1460template<typename _Tp> struct __cxx_is_always_lock_free {
1461    enum { __value = __atomic_always_lock_free(sizeof(_Tp), 0) }; };
1462
1463#else
1464
1465template<typename _Tp> struct __cxx_is_always_lock_free { enum { __value = false }; };
1466// Implementations must match the C ATOMIC_*_LOCK_FREE macro values.
1467template<> struct __cxx_is_always_lock_free<bool> { enum { __value = 2 == ATOMIC_BOOL_LOCK_FREE }; };
1468template<> struct __cxx_is_always_lock_free<char> { enum { __value = 2 == ATOMIC_CHAR_LOCK_FREE }; };
1469template<> struct __cxx_is_always_lock_free<signed char> { enum { __value = 2 == ATOMIC_CHAR_LOCK_FREE }; };
1470template<> struct __cxx_is_always_lock_free<unsigned char> { enum { __value = 2 == ATOMIC_CHAR_LOCK_FREE }; };
1471#ifndef _LIBCPP_HAS_NO_CHAR8_T
1472template<> struct __cxx_is_always_lock_free<char8_t> { enum { __value = 2 == ATOMIC_CHAR8_T_LOCK_FREE }; };
1473#endif
1474template<> struct __cxx_is_always_lock_free<char16_t> { enum { __value = 2 == ATOMIC_CHAR16_T_LOCK_FREE }; };
1475template<> struct __cxx_is_always_lock_free<char32_t> { enum { __value = 2 == ATOMIC_CHAR32_T_LOCK_FREE }; };
1476#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
1477template<> struct __cxx_is_always_lock_free<wchar_t> { enum { __value = 2 == ATOMIC_WCHAR_T_LOCK_FREE }; };
1478#endif
1479template<> struct __cxx_is_always_lock_free<short> { enum { __value = 2 == ATOMIC_SHORT_LOCK_FREE }; };
1480template<> struct __cxx_is_always_lock_free<unsigned short> { enum { __value = 2 == ATOMIC_SHORT_LOCK_FREE }; };
1481template<> struct __cxx_is_always_lock_free<int> { enum { __value = 2 == ATOMIC_INT_LOCK_FREE }; };
1482template<> struct __cxx_is_always_lock_free<unsigned int> { enum { __value = 2 == ATOMIC_INT_LOCK_FREE }; };
1483template<> struct __cxx_is_always_lock_free<long> { enum { __value = 2 == ATOMIC_LONG_LOCK_FREE }; };
1484template<> struct __cxx_is_always_lock_free<unsigned long> { enum { __value = 2 == ATOMIC_LONG_LOCK_FREE }; };
1485template<> struct __cxx_is_always_lock_free<long long> { enum { __value = 2 == ATOMIC_LLONG_LOCK_FREE }; };
1486template<> struct __cxx_is_always_lock_free<unsigned long long> { enum { __value = 2 == ATOMIC_LLONG_LOCK_FREE }; };
1487template<typename _Tp> struct __cxx_is_always_lock_free<_Tp*> { enum { __value = 2 == ATOMIC_POINTER_LOCK_FREE }; };
1488template<> struct __cxx_is_always_lock_free<std::nullptr_t> { enum { __value = 2 == ATOMIC_POINTER_LOCK_FREE }; };
1489
1490#endif //__cpp_lib_atomic_is_always_lock_free
1491
1492template <typename _Tp,
1493          typename _Base = typename conditional<__cxx_is_always_lock_free<_Tp>::__value,
1494                                                __cxx_atomic_base_impl<_Tp>,
1495                                                __cxx_atomic_lock_impl<_Tp> >::type>
1496#else
1497template <typename _Tp,
1498          typename _Base = __cxx_atomic_base_impl<_Tp> >
1499#endif //_LIBCPP_ATOMIC_ONLY_USE_BUILTINS
1500struct __cxx_atomic_impl : public _Base {
1501    static_assert(is_trivially_copyable<_Tp>::value,
1502      "std::atomic<Tp> requires that 'Tp' be a trivially copyable type");
1503
1504  _LIBCPP_INLINE_VISIBILITY __cxx_atomic_impl() _NOEXCEPT _LIBCPP_DEFAULT
1505  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR explicit __cxx_atomic_impl(_Tp value) _NOEXCEPT
1506    : _Base(value) {}
1507};
1508
1509#ifdef __linux__
1510    using __cxx_contention_t = int32_t;
1511#else
1512    using __cxx_contention_t = int64_t;
1513#endif //__linux__
1514
1515using __cxx_atomic_contention_t = __cxx_atomic_impl<__cxx_contention_t>;
1516
1517#ifndef _LIBCPP_HAS_NO_PLATFORM_WAIT
1518
1519_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(void const volatile*);
1520_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(void const volatile*);
1521_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(void const volatile*);
1522_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(void const volatile*, __cxx_contention_t);
1523
1524_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_contention_t const volatile*);
1525_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_contention_t const volatile*);
1526_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile*);
1527_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(__cxx_atomic_contention_t const volatile*, __cxx_contention_t);
1528
1529template <class _Atp, class _Fn>
1530struct __libcpp_atomic_wait_backoff_impl {
1531    _Atp* __a;
1532    _Fn __test_fn;
1533    _LIBCPP_AVAILABILITY_SYNC
1534    _LIBCPP_INLINE_VISIBILITY bool operator()(chrono::nanoseconds __elapsed) const
1535    {
1536        if(__elapsed > chrono::microseconds(64))
1537        {
1538            auto const __monitor = __libcpp_atomic_monitor(__a);
1539            if(__test_fn())
1540                return true;
1541            __libcpp_atomic_wait(__a, __monitor);
1542        }
1543        else if(__elapsed > chrono::microseconds(4))
1544            __libcpp_thread_yield();
1545        else
1546            {} // poll
1547        return false;
1548    }
1549};
1550
1551template <class _Atp, class _Fn>
1552_LIBCPP_AVAILABILITY_SYNC
1553_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Fn && __test_fn)
1554{
1555    __libcpp_atomic_wait_backoff_impl<_Atp, typename decay<_Fn>::type> __backoff_fn = {__a, __test_fn};
1556    return __libcpp_thread_poll_with_backoff(__test_fn, __backoff_fn);
1557}
1558
1559#else // _LIBCPP_HAS_NO_PLATFORM_WAIT
1560
1561template <class _Tp>
1562_LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_all(__cxx_atomic_impl<_Tp> const volatile*) { }
1563template <class _Tp>
1564_LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_one(__cxx_atomic_impl<_Tp> const volatile*) { }
1565template <class _Atp, class _Fn>
1566_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp*, _Fn && __test_fn)
1567{
1568    return __libcpp_thread_poll_with_backoff(__test_fn, __libcpp_timed_backoff_policy());
1569}
1570
1571#endif // _LIBCPP_HAS_NO_PLATFORM_WAIT
1572
1573template <class _Atp, class _Tp>
1574struct __cxx_atomic_wait_test_fn_impl {
1575    _Atp* __a;
1576    _Tp __val;
1577    memory_order __order;
1578    _LIBCPP_INLINE_VISIBILITY bool operator()() const
1579    {
1580        return !__cxx_nonatomic_compare_equal(__cxx_atomic_load(__a, __order), __val);
1581    }
1582};
1583
1584template <class _Atp, class _Tp>
1585_LIBCPP_AVAILABILITY_SYNC
1586_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Tp const __val, memory_order __order)
1587{
1588    __cxx_atomic_wait_test_fn_impl<_Atp, _Tp> __test_fn = {__a, __val, __order};
1589    return __cxx_atomic_wait(__a, __test_fn);
1590}
1591
1592// general atomic<T>
1593
1594template <class _Tp, bool = is_integral<_Tp>::value && !is_same<_Tp, bool>::value>
1595struct __atomic_base  // false
1596{
1597    mutable __cxx_atomic_impl<_Tp> __a_;
1598
1599#if defined(__cpp_lib_atomic_is_always_lock_free)
1600  static _LIBCPP_CONSTEXPR bool is_always_lock_free = __atomic_always_lock_free(sizeof(__a_), 0);
1601#endif
1602
1603    _LIBCPP_INLINE_VISIBILITY
1604    bool is_lock_free() const volatile _NOEXCEPT
1605        {return __cxx_atomic_is_lock_free(sizeof(_Tp));}
1606    _LIBCPP_INLINE_VISIBILITY
1607    bool is_lock_free() const _NOEXCEPT
1608        {return static_cast<__atomic_base const volatile*>(this)->is_lock_free();}
1609    _LIBCPP_INLINE_VISIBILITY
1610    void store(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1611      _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
1612        {__cxx_atomic_store(&__a_, __d, __m);}
1613    _LIBCPP_INLINE_VISIBILITY
1614    void store(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1615      _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
1616        {__cxx_atomic_store(&__a_, __d, __m);}
1617    _LIBCPP_INLINE_VISIBILITY
1618    _Tp load(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
1619      _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
1620        {return __cxx_atomic_load(&__a_, __m);}
1621    _LIBCPP_INLINE_VISIBILITY
1622    _Tp load(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
1623      _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
1624        {return __cxx_atomic_load(&__a_, __m);}
1625    _LIBCPP_INLINE_VISIBILITY
1626    operator _Tp() const volatile _NOEXCEPT {return load();}
1627    _LIBCPP_INLINE_VISIBILITY
1628    operator _Tp() const _NOEXCEPT          {return load();}
1629    _LIBCPP_INLINE_VISIBILITY
1630    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1631        {return __cxx_atomic_exchange(&__a_, __d, __m);}
1632    _LIBCPP_INLINE_VISIBILITY
1633    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1634        {return __cxx_atomic_exchange(&__a_, __d, __m);}
1635    _LIBCPP_INLINE_VISIBILITY
1636    bool compare_exchange_weak(_Tp& __e, _Tp __d,
1637                               memory_order __s, memory_order __f) volatile _NOEXCEPT
1638      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
1639        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
1640    _LIBCPP_INLINE_VISIBILITY
1641    bool compare_exchange_weak(_Tp& __e, _Tp __d,
1642                               memory_order __s, memory_order __f) _NOEXCEPT
1643      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
1644        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
1645    _LIBCPP_INLINE_VISIBILITY
1646    bool compare_exchange_strong(_Tp& __e, _Tp __d,
1647                                 memory_order __s, memory_order __f) volatile _NOEXCEPT
1648      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
1649        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
1650    _LIBCPP_INLINE_VISIBILITY
1651    bool compare_exchange_strong(_Tp& __e, _Tp __d,
1652                                 memory_order __s, memory_order __f) _NOEXCEPT
1653      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
1654        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
1655    _LIBCPP_INLINE_VISIBILITY
1656    bool compare_exchange_weak(_Tp& __e, _Tp __d,
1657                              memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1658        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
1659    _LIBCPP_INLINE_VISIBILITY
1660    bool compare_exchange_weak(_Tp& __e, _Tp __d,
1661                               memory_order __m = memory_order_seq_cst) _NOEXCEPT
1662        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
1663    _LIBCPP_INLINE_VISIBILITY
1664    bool compare_exchange_strong(_Tp& __e, _Tp __d,
1665                              memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1666        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
1667    _LIBCPP_INLINE_VISIBILITY
1668    bool compare_exchange_strong(_Tp& __e, _Tp __d,
1669                                 memory_order __m = memory_order_seq_cst) _NOEXCEPT
1670        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
1671
1672    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void wait(_Tp __v, memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
1673        {__cxx_atomic_wait(&__a_, __v, __m);}
1674    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void wait(_Tp __v, memory_order __m = memory_order_seq_cst) const _NOEXCEPT
1675        {__cxx_atomic_wait(&__a_, __v, __m);}
1676    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_one() volatile _NOEXCEPT
1677        {__cxx_atomic_notify_one(&__a_);}
1678    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_one() _NOEXCEPT
1679        {__cxx_atomic_notify_one(&__a_);}
1680    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_all() volatile _NOEXCEPT
1681        {__cxx_atomic_notify_all(&__a_);}
1682    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_all() _NOEXCEPT
1683        {__cxx_atomic_notify_all(&__a_);}
1684
1685#if _LIBCPP_STD_VER > 17
1686    _LIBCPP_INLINE_VISIBILITY constexpr
1687    __atomic_base() noexcept(is_nothrow_default_constructible_v<_Tp>) : __a_(_Tp()) {}
1688#else
1689    _LIBCPP_INLINE_VISIBILITY
1690    __atomic_base() _NOEXCEPT _LIBCPP_DEFAULT
1691#endif
1692
1693    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1694    __atomic_base(_Tp __d) _NOEXCEPT : __a_(__d) {}
1695
1696#ifndef _LIBCPP_CXX03_LANG
1697    __atomic_base(const __atomic_base&) = delete;
1698#else
1699private:
1700    _LIBCPP_INLINE_VISIBILITY
1701    __atomic_base(const __atomic_base&);
1702#endif
1703};
1704
1705#if defined(__cpp_lib_atomic_is_always_lock_free)
1706template <class _Tp, bool __b>
1707_LIBCPP_CONSTEXPR bool __atomic_base<_Tp, __b>::is_always_lock_free;
1708#endif
1709
1710// atomic<Integral>
1711
1712template <class _Tp>
1713struct __atomic_base<_Tp, true>
1714    : public __atomic_base<_Tp, false>
1715{
1716    typedef __atomic_base<_Tp, false> __base;
1717
1718    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1719    __atomic_base() _NOEXCEPT _LIBCPP_DEFAULT
1720
1721    _LIBCPP_INLINE_VISIBILITY
1722    _LIBCPP_CONSTEXPR __atomic_base(_Tp __d) _NOEXCEPT : __base(__d) {}
1723
1724    _LIBCPP_INLINE_VISIBILITY
1725    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1726        {return __cxx_atomic_fetch_add(&this->__a_, __op, __m);}
1727    _LIBCPP_INLINE_VISIBILITY
1728    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1729        {return __cxx_atomic_fetch_add(&this->__a_, __op, __m);}
1730    _LIBCPP_INLINE_VISIBILITY
1731    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1732        {return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
1733    _LIBCPP_INLINE_VISIBILITY
1734    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1735        {return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
1736    _LIBCPP_INLINE_VISIBILITY
1737    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1738        {return __cxx_atomic_fetch_and(&this->__a_, __op, __m);}
1739    _LIBCPP_INLINE_VISIBILITY
1740    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1741        {return __cxx_atomic_fetch_and(&this->__a_, __op, __m);}
1742    _LIBCPP_INLINE_VISIBILITY
1743    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1744        {return __cxx_atomic_fetch_or(&this->__a_, __op, __m);}
1745    _LIBCPP_INLINE_VISIBILITY
1746    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1747        {return __cxx_atomic_fetch_or(&this->__a_, __op, __m);}
1748    _LIBCPP_INLINE_VISIBILITY
1749    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
1750        {return __cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
1751    _LIBCPP_INLINE_VISIBILITY
1752    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
1753        {return __cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
1754
1755    _LIBCPP_INLINE_VISIBILITY
1756    _Tp operator++(int) volatile _NOEXCEPT      {return fetch_add(_Tp(1));}
1757    _LIBCPP_INLINE_VISIBILITY
1758    _Tp operator++(int) _NOEXCEPT               {return fetch_add(_Tp(1));}
1759    _LIBCPP_INLINE_VISIBILITY
1760    _Tp operator--(int) volatile _NOEXCEPT      {return fetch_sub(_Tp(1));}
1761    _LIBCPP_INLINE_VISIBILITY
1762    _Tp operator--(int) _NOEXCEPT               {return fetch_sub(_Tp(1));}
1763    _LIBCPP_INLINE_VISIBILITY
1764    _Tp operator++() volatile _NOEXCEPT         {return fetch_add(_Tp(1)) + _Tp(1);}
1765    _LIBCPP_INLINE_VISIBILITY
1766    _Tp operator++() _NOEXCEPT                  {return fetch_add(_Tp(1)) + _Tp(1);}
1767    _LIBCPP_INLINE_VISIBILITY
1768    _Tp operator--() volatile _NOEXCEPT         {return fetch_sub(_Tp(1)) - _Tp(1);}
1769    _LIBCPP_INLINE_VISIBILITY
1770    _Tp operator--() _NOEXCEPT                  {return fetch_sub(_Tp(1)) - _Tp(1);}
1771    _LIBCPP_INLINE_VISIBILITY
1772    _Tp operator+=(_Tp __op) volatile _NOEXCEPT {return fetch_add(__op) + __op;}
1773    _LIBCPP_INLINE_VISIBILITY
1774    _Tp operator+=(_Tp __op) _NOEXCEPT          {return fetch_add(__op) + __op;}
1775    _LIBCPP_INLINE_VISIBILITY
1776    _Tp operator-=(_Tp __op) volatile _NOEXCEPT {return fetch_sub(__op) - __op;}
1777    _LIBCPP_INLINE_VISIBILITY
1778    _Tp operator-=(_Tp __op) _NOEXCEPT          {return fetch_sub(__op) - __op;}
1779    _LIBCPP_INLINE_VISIBILITY
1780    _Tp operator&=(_Tp __op) volatile _NOEXCEPT {return fetch_and(__op) & __op;}
1781    _LIBCPP_INLINE_VISIBILITY
1782    _Tp operator&=(_Tp __op) _NOEXCEPT          {return fetch_and(__op) & __op;}
1783    _LIBCPP_INLINE_VISIBILITY
1784    _Tp operator|=(_Tp __op) volatile _NOEXCEPT {return fetch_or(__op) | __op;}
1785    _LIBCPP_INLINE_VISIBILITY
1786    _Tp operator|=(_Tp __op) _NOEXCEPT          {return fetch_or(__op) | __op;}
1787    _LIBCPP_INLINE_VISIBILITY
1788    _Tp operator^=(_Tp __op) volatile _NOEXCEPT {return fetch_xor(__op) ^ __op;}
1789    _LIBCPP_INLINE_VISIBILITY
1790    _Tp operator^=(_Tp __op) _NOEXCEPT          {return fetch_xor(__op) ^ __op;}
1791};
1792
1793// atomic<T>
1794
1795template <class _Tp>
1796struct atomic
1797    : public __atomic_base<_Tp>
1798{
1799    typedef __atomic_base<_Tp> __base;
1800    typedef _Tp value_type;
1801    typedef value_type difference_type;
1802
1803#if _LIBCPP_STD_VER > 17
1804    _LIBCPP_INLINE_VISIBILITY
1805    atomic() = default;
1806#else
1807    _LIBCPP_INLINE_VISIBILITY
1808    atomic() _NOEXCEPT _LIBCPP_DEFAULT
1809#endif
1810
1811    _LIBCPP_INLINE_VISIBILITY
1812    _LIBCPP_CONSTEXPR atomic(_Tp __d) _NOEXCEPT : __base(__d) {}
1813
1814    _LIBCPP_INLINE_VISIBILITY
1815    _Tp operator=(_Tp __d) volatile _NOEXCEPT
1816        {__base::store(__d); return __d;}
1817    _LIBCPP_INLINE_VISIBILITY
1818    _Tp operator=(_Tp __d) _NOEXCEPT
1819        {__base::store(__d); return __d;}
1820
1821    atomic& operator=(const atomic&) = delete;
1822    atomic& operator=(const atomic&) volatile = delete;
1823};
1824
1825// atomic<T*>
1826
1827template <class _Tp>
1828struct atomic<_Tp*>
1829    : public __atomic_base<_Tp*>
1830{
1831    typedef __atomic_base<_Tp*> __base;
1832    typedef _Tp* value_type;
1833    typedef ptrdiff_t difference_type;
1834
1835    _LIBCPP_INLINE_VISIBILITY
1836    atomic() _NOEXCEPT _LIBCPP_DEFAULT
1837
1838    _LIBCPP_INLINE_VISIBILITY
1839    _LIBCPP_CONSTEXPR atomic(_Tp* __d) _NOEXCEPT : __base(__d) {}
1840
1841    _LIBCPP_INLINE_VISIBILITY
1842    _Tp* operator=(_Tp* __d) volatile _NOEXCEPT
1843        {__base::store(__d); return __d;}
1844    _LIBCPP_INLINE_VISIBILITY
1845    _Tp* operator=(_Tp* __d) _NOEXCEPT
1846        {__base::store(__d); return __d;}
1847
1848    _LIBCPP_INLINE_VISIBILITY
1849    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT {
1850        // __atomic_fetch_add accepts function pointers, guard against them.
1851        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
1852        return __cxx_atomic_fetch_add(&this->__a_, __op, __m);
1853    }
1854
1855    _LIBCPP_INLINE_VISIBILITY
1856    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT {
1857        // __atomic_fetch_add accepts function pointers, guard against them.
1858        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
1859        return __cxx_atomic_fetch_add(&this->__a_, __op, __m);
1860    }
1861
1862    _LIBCPP_INLINE_VISIBILITY
1863    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT {
1864        // __atomic_fetch_add accepts function pointers, guard against them.
1865        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
1866        return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);
1867    }
1868
1869    _LIBCPP_INLINE_VISIBILITY
1870    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT {
1871        // __atomic_fetch_add accepts function pointers, guard against them.
1872        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
1873        return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);
1874    }
1875
1876    _LIBCPP_INLINE_VISIBILITY
1877    _Tp* operator++(int) volatile _NOEXCEPT            {return fetch_add(1);}
1878    _LIBCPP_INLINE_VISIBILITY
1879    _Tp* operator++(int) _NOEXCEPT                     {return fetch_add(1);}
1880    _LIBCPP_INLINE_VISIBILITY
1881    _Tp* operator--(int) volatile _NOEXCEPT            {return fetch_sub(1);}
1882    _LIBCPP_INLINE_VISIBILITY
1883    _Tp* operator--(int) _NOEXCEPT                     {return fetch_sub(1);}
1884    _LIBCPP_INLINE_VISIBILITY
1885    _Tp* operator++() volatile _NOEXCEPT               {return fetch_add(1) + 1;}
1886    _LIBCPP_INLINE_VISIBILITY
1887    _Tp* operator++() _NOEXCEPT                        {return fetch_add(1) + 1;}
1888    _LIBCPP_INLINE_VISIBILITY
1889    _Tp* operator--() volatile _NOEXCEPT               {return fetch_sub(1) - 1;}
1890    _LIBCPP_INLINE_VISIBILITY
1891    _Tp* operator--() _NOEXCEPT                        {return fetch_sub(1) - 1;}
1892    _LIBCPP_INLINE_VISIBILITY
1893    _Tp* operator+=(ptrdiff_t __op) volatile _NOEXCEPT {return fetch_add(__op) + __op;}
1894    _LIBCPP_INLINE_VISIBILITY
1895    _Tp* operator+=(ptrdiff_t __op) _NOEXCEPT          {return fetch_add(__op) + __op;}
1896    _LIBCPP_INLINE_VISIBILITY
1897    _Tp* operator-=(ptrdiff_t __op) volatile _NOEXCEPT {return fetch_sub(__op) - __op;}
1898    _LIBCPP_INLINE_VISIBILITY
1899    _Tp* operator-=(ptrdiff_t __op) _NOEXCEPT          {return fetch_sub(__op) - __op;}
1900
1901    atomic& operator=(const atomic&) = delete;
1902    atomic& operator=(const atomic&) volatile = delete;
1903};
1904
1905// atomic_is_lock_free
1906
1907template <class _Tp>
1908_LIBCPP_INLINE_VISIBILITY
1909bool
1910atomic_is_lock_free(const volatile atomic<_Tp>* __o) _NOEXCEPT
1911{
1912    return __o->is_lock_free();
1913}
1914
1915template <class _Tp>
1916_LIBCPP_INLINE_VISIBILITY
1917bool
1918atomic_is_lock_free(const atomic<_Tp>* __o) _NOEXCEPT
1919{
1920    return __o->is_lock_free();
1921}
1922
1923// atomic_init
1924
1925template <class _Tp>
1926_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
1927void
1928atomic_init(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1929{
1930    __cxx_atomic_init(&__o->__a_, __d);
1931}
1932
1933template <class _Tp>
1934_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
1935void
1936atomic_init(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1937{
1938    __cxx_atomic_init(&__o->__a_, __d);
1939}
1940
1941// atomic_store
1942
1943template <class _Tp>
1944_LIBCPP_INLINE_VISIBILITY
1945void
1946atomic_store(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1947{
1948    __o->store(__d);
1949}
1950
1951template <class _Tp>
1952_LIBCPP_INLINE_VISIBILITY
1953void
1954atomic_store(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
1955{
1956    __o->store(__d);
1957}
1958
1959// atomic_store_explicit
1960
1961template <class _Tp>
1962_LIBCPP_INLINE_VISIBILITY
1963void
1964atomic_store_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
1965  _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
1966{
1967    __o->store(__d, __m);
1968}
1969
1970template <class _Tp>
1971_LIBCPP_INLINE_VISIBILITY
1972void
1973atomic_store_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
1974  _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
1975{
1976    __o->store(__d, __m);
1977}
1978
1979// atomic_load
1980
1981template <class _Tp>
1982_LIBCPP_INLINE_VISIBILITY
1983_Tp
1984atomic_load(const volatile atomic<_Tp>* __o) _NOEXCEPT
1985{
1986    return __o->load();
1987}
1988
1989template <class _Tp>
1990_LIBCPP_INLINE_VISIBILITY
1991_Tp
1992atomic_load(const atomic<_Tp>* __o) _NOEXCEPT
1993{
1994    return __o->load();
1995}
1996
1997// atomic_load_explicit
1998
1999template <class _Tp>
2000_LIBCPP_INLINE_VISIBILITY
2001_Tp
2002atomic_load_explicit(const volatile atomic<_Tp>* __o, memory_order __m) _NOEXCEPT
2003  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
2004{
2005    return __o->load(__m);
2006}
2007
2008template <class _Tp>
2009_LIBCPP_INLINE_VISIBILITY
2010_Tp
2011atomic_load_explicit(const atomic<_Tp>* __o, memory_order __m) _NOEXCEPT
2012  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
2013{
2014    return __o->load(__m);
2015}
2016
2017// atomic_exchange
2018
2019template <class _Tp>
2020_LIBCPP_INLINE_VISIBILITY
2021_Tp
2022atomic_exchange(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
2023{
2024    return __o->exchange(__d);
2025}
2026
2027template <class _Tp>
2028_LIBCPP_INLINE_VISIBILITY
2029_Tp
2030atomic_exchange(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
2031{
2032    return __o->exchange(__d);
2033}
2034
2035// atomic_exchange_explicit
2036
2037template <class _Tp>
2038_LIBCPP_INLINE_VISIBILITY
2039_Tp
2040atomic_exchange_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
2041{
2042    return __o->exchange(__d, __m);
2043}
2044
2045template <class _Tp>
2046_LIBCPP_INLINE_VISIBILITY
2047_Tp
2048atomic_exchange_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
2049{
2050    return __o->exchange(__d, __m);
2051}
2052
2053// atomic_compare_exchange_weak
2054
2055template <class _Tp>
2056_LIBCPP_INLINE_VISIBILITY
2057bool
2058atomic_compare_exchange_weak(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
2059{
2060    return __o->compare_exchange_weak(*__e, __d);
2061}
2062
2063template <class _Tp>
2064_LIBCPP_INLINE_VISIBILITY
2065bool
2066atomic_compare_exchange_weak(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
2067{
2068    return __o->compare_exchange_weak(*__e, __d);
2069}
2070
2071// atomic_compare_exchange_strong
2072
2073template <class _Tp>
2074_LIBCPP_INLINE_VISIBILITY
2075bool
2076atomic_compare_exchange_strong(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
2077{
2078    return __o->compare_exchange_strong(*__e, __d);
2079}
2080
2081template <class _Tp>
2082_LIBCPP_INLINE_VISIBILITY
2083bool
2084atomic_compare_exchange_strong(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
2085{
2086    return __o->compare_exchange_strong(*__e, __d);
2087}
2088
2089// atomic_compare_exchange_weak_explicit
2090
2091template <class _Tp>
2092_LIBCPP_INLINE_VISIBILITY
2093bool
2094atomic_compare_exchange_weak_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e,
2095                                      typename atomic<_Tp>::value_type __d,
2096                                      memory_order __s, memory_order __f) _NOEXCEPT
2097  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
2098{
2099    return __o->compare_exchange_weak(*__e, __d, __s, __f);
2100}
2101
2102template <class _Tp>
2103_LIBCPP_INLINE_VISIBILITY
2104bool
2105atomic_compare_exchange_weak_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d,
2106                                      memory_order __s, memory_order __f) _NOEXCEPT
2107  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
2108{
2109    return __o->compare_exchange_weak(*__e, __d, __s, __f);
2110}
2111
2112// atomic_compare_exchange_strong_explicit
2113
2114template <class _Tp>
2115_LIBCPP_INLINE_VISIBILITY
2116bool
2117atomic_compare_exchange_strong_explicit(volatile atomic<_Tp>* __o,
2118                                        typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d,
2119                                        memory_order __s, memory_order __f) _NOEXCEPT
2120  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
2121{
2122    return __o->compare_exchange_strong(*__e, __d, __s, __f);
2123}
2124
2125template <class _Tp>
2126_LIBCPP_INLINE_VISIBILITY
2127bool
2128atomic_compare_exchange_strong_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e,
2129                                        typename atomic<_Tp>::value_type __d,
2130                                        memory_order __s, memory_order __f) _NOEXCEPT
2131  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
2132{
2133    return __o->compare_exchange_strong(*__e, __d, __s, __f);
2134}
2135
2136// atomic_wait
2137
2138template <class _Tp>
2139_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2140void atomic_wait(const volatile atomic<_Tp>* __o,
2141                 typename atomic<_Tp>::value_type __v) _NOEXCEPT
2142{
2143    return __o->wait(__v);
2144}
2145
2146template <class _Tp>
2147_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2148void atomic_wait(const atomic<_Tp>* __o,
2149                 typename atomic<_Tp>::value_type __v) _NOEXCEPT
2150{
2151    return __o->wait(__v);
2152}
2153
2154// atomic_wait_explicit
2155
2156template <class _Tp>
2157_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2158void atomic_wait_explicit(const volatile atomic<_Tp>* __o,
2159                          typename atomic<_Tp>::value_type __v,
2160                          memory_order __m) _NOEXCEPT
2161  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
2162{
2163    return __o->wait(__v, __m);
2164}
2165
2166template <class _Tp>
2167_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2168void atomic_wait_explicit(const atomic<_Tp>* __o,
2169                          typename atomic<_Tp>::value_type __v,
2170                          memory_order __m) _NOEXCEPT
2171  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
2172{
2173    return __o->wait(__v, __m);
2174}
2175
2176// atomic_notify_one
2177
2178template <class _Tp>
2179_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2180void atomic_notify_one(volatile atomic<_Tp>* __o) _NOEXCEPT
2181{
2182    __o->notify_one();
2183}
2184template <class _Tp>
2185_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2186void atomic_notify_one(atomic<_Tp>* __o) _NOEXCEPT
2187{
2188    __o->notify_one();
2189}
2190
2191// atomic_notify_one
2192
2193template <class _Tp>
2194_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2195void atomic_notify_all(volatile atomic<_Tp>* __o) _NOEXCEPT
2196{
2197    __o->notify_all();
2198}
2199template <class _Tp>
2200_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2201void atomic_notify_all(atomic<_Tp>* __o) _NOEXCEPT
2202{
2203    __o->notify_all();
2204}
2205
2206// atomic_fetch_add
2207
2208template <class _Tp>
2209_LIBCPP_INLINE_VISIBILITY
2210_Tp
2211atomic_fetch_add(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
2212{
2213    return __o->fetch_add(__op);
2214}
2215
2216template <class _Tp>
2217_LIBCPP_INLINE_VISIBILITY
2218_Tp
2219atomic_fetch_add(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
2220{
2221    return __o->fetch_add(__op);
2222}
2223
2224// atomic_fetch_add_explicit
2225
2226template <class _Tp>
2227_LIBCPP_INLINE_VISIBILITY
2228_Tp atomic_fetch_add_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
2229{
2230    return __o->fetch_add(__op, __m);
2231}
2232
2233template <class _Tp>
2234_LIBCPP_INLINE_VISIBILITY
2235_Tp atomic_fetch_add_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
2236{
2237    return __o->fetch_add(__op, __m);
2238}
2239
2240// atomic_fetch_sub
2241
2242template <class _Tp>
2243_LIBCPP_INLINE_VISIBILITY
2244_Tp atomic_fetch_sub(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
2245{
2246    return __o->fetch_sub(__op);
2247}
2248
2249template <class _Tp>
2250_LIBCPP_INLINE_VISIBILITY
2251_Tp atomic_fetch_sub(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
2252{
2253    return __o->fetch_sub(__op);
2254}
2255
2256// atomic_fetch_sub_explicit
2257
2258template <class _Tp>
2259_LIBCPP_INLINE_VISIBILITY
2260_Tp atomic_fetch_sub_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
2261{
2262    return __o->fetch_sub(__op, __m);
2263}
2264
2265template <class _Tp>
2266_LIBCPP_INLINE_VISIBILITY
2267_Tp atomic_fetch_sub_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
2268{
2269    return __o->fetch_sub(__op, __m);
2270}
2271
2272// atomic_fetch_and
2273
2274template <class _Tp>
2275_LIBCPP_INLINE_VISIBILITY
2276typename enable_if
2277<
2278    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2279    _Tp
2280>::type
2281atomic_fetch_and(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2282{
2283    return __o->fetch_and(__op);
2284}
2285
2286template <class _Tp>
2287_LIBCPP_INLINE_VISIBILITY
2288typename enable_if
2289<
2290    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2291    _Tp
2292>::type
2293atomic_fetch_and(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2294{
2295    return __o->fetch_and(__op);
2296}
2297
2298// atomic_fetch_and_explicit
2299
2300template <class _Tp>
2301_LIBCPP_INLINE_VISIBILITY
2302typename enable_if
2303<
2304    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2305    _Tp
2306>::type
2307atomic_fetch_and_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2308{
2309    return __o->fetch_and(__op, __m);
2310}
2311
2312template <class _Tp>
2313_LIBCPP_INLINE_VISIBILITY
2314typename enable_if
2315<
2316    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2317    _Tp
2318>::type
2319atomic_fetch_and_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2320{
2321    return __o->fetch_and(__op, __m);
2322}
2323
2324// atomic_fetch_or
2325
2326template <class _Tp>
2327_LIBCPP_INLINE_VISIBILITY
2328typename enable_if
2329<
2330    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2331    _Tp
2332>::type
2333atomic_fetch_or(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2334{
2335    return __o->fetch_or(__op);
2336}
2337
2338template <class _Tp>
2339_LIBCPP_INLINE_VISIBILITY
2340typename enable_if
2341<
2342    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2343    _Tp
2344>::type
2345atomic_fetch_or(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2346{
2347    return __o->fetch_or(__op);
2348}
2349
2350// atomic_fetch_or_explicit
2351
2352template <class _Tp>
2353_LIBCPP_INLINE_VISIBILITY
2354typename enable_if
2355<
2356    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2357    _Tp
2358>::type
2359atomic_fetch_or_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2360{
2361    return __o->fetch_or(__op, __m);
2362}
2363
2364template <class _Tp>
2365_LIBCPP_INLINE_VISIBILITY
2366typename enable_if
2367<
2368    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2369    _Tp
2370>::type
2371atomic_fetch_or_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2372{
2373    return __o->fetch_or(__op, __m);
2374}
2375
2376// atomic_fetch_xor
2377
2378template <class _Tp>
2379_LIBCPP_INLINE_VISIBILITY
2380typename enable_if
2381<
2382    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2383    _Tp
2384>::type
2385atomic_fetch_xor(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2386{
2387    return __o->fetch_xor(__op);
2388}
2389
2390template <class _Tp>
2391_LIBCPP_INLINE_VISIBILITY
2392typename enable_if
2393<
2394    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2395    _Tp
2396>::type
2397atomic_fetch_xor(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
2398{
2399    return __o->fetch_xor(__op);
2400}
2401
2402// atomic_fetch_xor_explicit
2403
2404template <class _Tp>
2405_LIBCPP_INLINE_VISIBILITY
2406typename enable_if
2407<
2408    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2409    _Tp
2410>::type
2411atomic_fetch_xor_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2412{
2413    return __o->fetch_xor(__op, __m);
2414}
2415
2416template <class _Tp>
2417_LIBCPP_INLINE_VISIBILITY
2418typename enable_if
2419<
2420    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
2421    _Tp
2422>::type
2423atomic_fetch_xor_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
2424{
2425    return __o->fetch_xor(__op, __m);
2426}
2427
2428// flag type and operations
2429
2430typedef struct atomic_flag
2431{
2432    __cxx_atomic_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_;
2433
2434    _LIBCPP_INLINE_VISIBILITY
2435    bool test(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
2436        {return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
2437    _LIBCPP_INLINE_VISIBILITY
2438    bool test(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
2439        {return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
2440
2441    _LIBCPP_INLINE_VISIBILITY
2442    bool test_and_set(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
2443        {return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
2444    _LIBCPP_INLINE_VISIBILITY
2445    bool test_and_set(memory_order __m = memory_order_seq_cst) _NOEXCEPT
2446        {return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
2447    _LIBCPP_INLINE_VISIBILITY
2448    void clear(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
2449        {__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
2450    _LIBCPP_INLINE_VISIBILITY
2451    void clear(memory_order __m = memory_order_seq_cst) _NOEXCEPT
2452        {__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
2453
2454    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2455    void wait(bool __v, memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
2456        {__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
2457    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2458    void wait(bool __v, memory_order __m = memory_order_seq_cst) const _NOEXCEPT
2459        {__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
2460    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2461    void notify_one() volatile _NOEXCEPT
2462        {__cxx_atomic_notify_one(&__a_);}
2463    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2464    void notify_one() _NOEXCEPT
2465        {__cxx_atomic_notify_one(&__a_);}
2466    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2467    void notify_all() volatile _NOEXCEPT
2468        {__cxx_atomic_notify_all(&__a_);}
2469    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
2470    void notify_all() _NOEXCEPT
2471        {__cxx_atomic_notify_all(&__a_);}
2472
2473#if _LIBCPP_STD_VER > 17
2474    _LIBCPP_INLINE_VISIBILITY constexpr
2475    atomic_flag() _NOEXCEPT : __a_(false) {}
2476#else
2477    _LIBCPP_INLINE_VISIBILITY
2478    atomic_flag() _NOEXCEPT _LIBCPP_DEFAULT
2479#endif
2480
2481    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2482    atomic_flag(bool __b) _NOEXCEPT : __a_(__b) {} // EXTENSION
2483
2484#ifndef _LIBCPP_CXX03_LANG
2485    atomic_flag(const atomic_flag&) = delete;
2486    atomic_flag& operator=(const atomic_flag&) = delete;
2487    atomic_flag& operator=(const atomic_flag&) volatile = delete;
2488#else
2489private:
2490    _LIBCPP_INLINE_VISIBILITY
2491    atomic_flag(const atomic_flag&);
2492    _LIBCPP_INLINE_VISIBILITY
2493    atomic_flag& operator=(const atomic_flag&);
2494    _LIBCPP_INLINE_VISIBILITY
2495    atomic_flag& operator=(const atomic_flag&) volatile;
2496#endif
2497} atomic_flag;
2498
2499
2500inline _LIBCPP_INLINE_VISIBILITY
2501bool
2502atomic_flag_test(const volatile atomic_flag* __o) _NOEXCEPT
2503{
2504    return __o->test();
2505}
2506
2507inline _LIBCPP_INLINE_VISIBILITY
2508bool
2509atomic_flag_test(const atomic_flag* __o) _NOEXCEPT
2510{
2511    return __o->test();
2512}
2513
2514inline _LIBCPP_INLINE_VISIBILITY
2515bool
2516atomic_flag_test_explicit(const volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
2517{
2518    return __o->test(__m);
2519}
2520
2521inline _LIBCPP_INLINE_VISIBILITY
2522bool
2523atomic_flag_test_explicit(const atomic_flag* __o, memory_order __m) _NOEXCEPT
2524{
2525    return __o->test(__m);
2526}
2527
2528inline _LIBCPP_INLINE_VISIBILITY
2529bool
2530atomic_flag_test_and_set(volatile atomic_flag* __o) _NOEXCEPT
2531{
2532    return __o->test_and_set();
2533}
2534
2535inline _LIBCPP_INLINE_VISIBILITY
2536bool
2537atomic_flag_test_and_set(atomic_flag* __o) _NOEXCEPT
2538{
2539    return __o->test_and_set();
2540}
2541
2542inline _LIBCPP_INLINE_VISIBILITY
2543bool
2544atomic_flag_test_and_set_explicit(volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
2545{
2546    return __o->test_and_set(__m);
2547}
2548
2549inline _LIBCPP_INLINE_VISIBILITY
2550bool
2551atomic_flag_test_and_set_explicit(atomic_flag* __o, memory_order __m) _NOEXCEPT
2552{
2553    return __o->test_and_set(__m);
2554}
2555
2556inline _LIBCPP_INLINE_VISIBILITY
2557void
2558atomic_flag_clear(volatile atomic_flag* __o) _NOEXCEPT
2559{
2560    __o->clear();
2561}
2562
2563inline _LIBCPP_INLINE_VISIBILITY
2564void
2565atomic_flag_clear(atomic_flag* __o) _NOEXCEPT
2566{
2567    __o->clear();
2568}
2569
2570inline _LIBCPP_INLINE_VISIBILITY
2571void
2572atomic_flag_clear_explicit(volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
2573{
2574    __o->clear(__m);
2575}
2576
2577inline _LIBCPP_INLINE_VISIBILITY
2578void
2579atomic_flag_clear_explicit(atomic_flag* __o, memory_order __m) _NOEXCEPT
2580{
2581    __o->clear(__m);
2582}
2583
2584inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2585void
2586atomic_flag_wait(const volatile atomic_flag* __o, bool __v) _NOEXCEPT
2587{
2588    __o->wait(__v);
2589}
2590
2591inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2592void
2593atomic_flag_wait(const atomic_flag* __o, bool __v) _NOEXCEPT
2594{
2595    __o->wait(__v);
2596}
2597
2598inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2599void
2600atomic_flag_wait_explicit(const volatile atomic_flag* __o,
2601                          bool __v, memory_order __m) _NOEXCEPT
2602{
2603    __o->wait(__v, __m);
2604}
2605
2606inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2607void
2608atomic_flag_wait_explicit(const atomic_flag* __o,
2609                          bool __v, memory_order __m) _NOEXCEPT
2610{
2611    __o->wait(__v, __m);
2612}
2613
2614inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2615void
2616atomic_flag_notify_one(volatile atomic_flag* __o) _NOEXCEPT
2617{
2618    __o->notify_one();
2619}
2620
2621inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2622void
2623atomic_flag_notify_one(atomic_flag* __o) _NOEXCEPT
2624{
2625    __o->notify_one();
2626}
2627
2628inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2629void
2630atomic_flag_notify_all(volatile atomic_flag* __o) _NOEXCEPT
2631{
2632    __o->notify_all();
2633}
2634
2635inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
2636void
2637atomic_flag_notify_all(atomic_flag* __o) _NOEXCEPT
2638{
2639    __o->notify_all();
2640}
2641
2642// fences
2643
2644inline _LIBCPP_INLINE_VISIBILITY
2645void
2646atomic_thread_fence(memory_order __m) _NOEXCEPT
2647{
2648    __cxx_atomic_thread_fence(__m);
2649}
2650
2651inline _LIBCPP_INLINE_VISIBILITY
2652void
2653atomic_signal_fence(memory_order __m) _NOEXCEPT
2654{
2655    __cxx_atomic_signal_fence(__m);
2656}
2657
2658// Atomics for standard typedef types
2659
2660typedef atomic<bool>               atomic_bool;
2661typedef atomic<char>               atomic_char;
2662typedef atomic<signed char>        atomic_schar;
2663typedef atomic<unsigned char>      atomic_uchar;
2664typedef atomic<short>              atomic_short;
2665typedef atomic<unsigned short>     atomic_ushort;
2666typedef atomic<int>                atomic_int;
2667typedef atomic<unsigned int>       atomic_uint;
2668typedef atomic<long>               atomic_long;
2669typedef atomic<unsigned long>      atomic_ulong;
2670typedef atomic<long long>          atomic_llong;
2671typedef atomic<unsigned long long> atomic_ullong;
2672#ifndef _LIBCPP_HAS_NO_CHAR8_T
2673typedef atomic<char8_t>            atomic_char8_t;
2674#endif
2675typedef atomic<char16_t>           atomic_char16_t;
2676typedef atomic<char32_t>           atomic_char32_t;
2677#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
2678typedef atomic<wchar_t>            atomic_wchar_t;
2679#endif
2680
2681typedef atomic<int_least8_t>   atomic_int_least8_t;
2682typedef atomic<uint_least8_t>  atomic_uint_least8_t;
2683typedef atomic<int_least16_t>  atomic_int_least16_t;
2684typedef atomic<uint_least16_t> atomic_uint_least16_t;
2685typedef atomic<int_least32_t>  atomic_int_least32_t;
2686typedef atomic<uint_least32_t> atomic_uint_least32_t;
2687typedef atomic<int_least64_t>  atomic_int_least64_t;
2688typedef atomic<uint_least64_t> atomic_uint_least64_t;
2689
2690typedef atomic<int_fast8_t>   atomic_int_fast8_t;
2691typedef atomic<uint_fast8_t>  atomic_uint_fast8_t;
2692typedef atomic<int_fast16_t>  atomic_int_fast16_t;
2693typedef atomic<uint_fast16_t> atomic_uint_fast16_t;
2694typedef atomic<int_fast32_t>  atomic_int_fast32_t;
2695typedef atomic<uint_fast32_t> atomic_uint_fast32_t;
2696typedef atomic<int_fast64_t>  atomic_int_fast64_t;
2697typedef atomic<uint_fast64_t> atomic_uint_fast64_t;
2698
2699typedef atomic< int8_t>  atomic_int8_t;
2700typedef atomic<uint8_t>  atomic_uint8_t;
2701typedef atomic< int16_t> atomic_int16_t;
2702typedef atomic<uint16_t> atomic_uint16_t;
2703typedef atomic< int32_t> atomic_int32_t;
2704typedef atomic<uint32_t> atomic_uint32_t;
2705typedef atomic< int64_t> atomic_int64_t;
2706typedef atomic<uint64_t> atomic_uint64_t;
2707
2708typedef atomic<intptr_t>  atomic_intptr_t;
2709typedef atomic<uintptr_t> atomic_uintptr_t;
2710typedef atomic<size_t>    atomic_size_t;
2711typedef atomic<ptrdiff_t> atomic_ptrdiff_t;
2712typedef atomic<intmax_t>  atomic_intmax_t;
2713typedef atomic<uintmax_t> atomic_uintmax_t;
2714
2715// atomic_*_lock_free : prefer the contention type most highly, then the largest lock-free type
2716
2717#ifdef __cpp_lib_atomic_is_always_lock_free
2718# define _LIBCPP_CONTENTION_LOCK_FREE __atomic_always_lock_free(sizeof(__cxx_contention_t), 0)
2719#else
2720# define _LIBCPP_CONTENTION_LOCK_FREE false
2721#endif
2722
2723#if ATOMIC_LLONG_LOCK_FREE == 2
2724typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, long long>::type          __libcpp_signed_lock_free;
2725typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned long long>::type __libcpp_unsigned_lock_free;
2726#elif ATOMIC_INT_LOCK_FREE == 2
2727typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, int>::type                __libcpp_signed_lock_free;
2728typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned int>::type       __libcpp_unsigned_lock_free;
2729#elif ATOMIC_SHORT_LOCK_FREE == 2
2730typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, short>::type              __libcpp_signed_lock_free;
2731typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned short>::type     __libcpp_unsigned_lock_free;
2732#elif ATOMIC_CHAR_LOCK_FREE == 2
2733typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, char>::type               __libcpp_signed_lock_free;
2734typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned char>::type      __libcpp_unsigned_lock_free;
2735#else
2736    // No signed/unsigned lock-free types
2737#endif
2738
2739typedef atomic<__libcpp_signed_lock_free> atomic_signed_lock_free;
2740typedef atomic<__libcpp_unsigned_lock_free> atomic_unsigned_lock_free;
2741
2742#define ATOMIC_FLAG_INIT {false}
2743#define ATOMIC_VAR_INIT(__v) {__v}
2744
2745_LIBCPP_END_NAMESPACE_STD
2746
2747#endif // _LIBCPP_ATOMIC
2748