Allow stdatomic.h to be included from mingw prebuilt.
[android-sdk/platform-bionic.git] / libc / include / stdatomic.h
1 /*-
2  * Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org>
3  *                    David Chisnall <theraven@FreeBSD.org>
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  * $FreeBSD$
28  */
30 #ifndef _STDATOMIC_H_
31 #define _STDATOMIC_H_
33 #include <sys/cdefs.h>
35 #if defined(__GNUC__) && !defined(__GNUC_PREREQ)
36 /* Duplicate definition here, since the mingw sys/cdefs.h omits the  */
37 /* definition, and this needs to be usable there.                    */
38 #define __GNUC_PREREQ(x, y)    \
39         ((__GNUC__ == (x) && __GNUC_MINOR__ >= (y)) || (__GNUC__ > (x)))
40 #endif /* __GNUC__ && ... */
42 #if defined(__cplusplus) && __cplusplus >= 201103L && defined(_USING_LIBCXX)
43 # ifdef __clang__
44 #  if __has_feature(cxx_atomic)
45 #   define _STDATOMIC_HAVE_ATOMIC
46 #  endif
47 # else /* gcc */
48 #  if __GNUC_PREREQ(4, 7)
49 #   define _STDATOMIC_HAVE_ATOMIC
50 #  endif
51 # endif
52 #endif
54 #ifdef _STDATOMIC_HAVE_ATOMIC
56 /* We have a usable C++ <atomic>; use it instead.  */
58 #include <atomic>
60 #undef _Atomic
61         /* Also defined by <atomic> for gcc.  But not used in macros. */
62         /* Also a clang intrinsic.                                    */
63         /* Should not be used by client code before this file is      */
64         /* included.  The definitions in <atomic> themselves see      */
65         /* the old definition, as they should.                        */
66         /* Client code sees the following definition.                 */
68 #define _Atomic(t) std::atomic<t>
70 using std::atomic_is_lock_free;
71 using std::atomic_init;
72 using std::atomic_store;
73 using std::atomic_store_explicit;
74 using std::atomic_load;
75 using std::atomic_load_explicit;
76 using std::atomic_exchange;
77 using std::atomic_exchange_explicit;
78 using std::atomic_compare_exchange_strong;
79 using std::atomic_compare_exchange_strong_explicit;
80 using std::atomic_compare_exchange_weak;
81 using std::atomic_compare_exchange_weak_explicit;
82 using std::atomic_fetch_add;
83 using std::atomic_fetch_add_explicit;
84 using std::atomic_fetch_sub;
85 using std::atomic_fetch_sub_explicit;
86 using std::atomic_fetch_or;
87 using std::atomic_fetch_or_explicit;
88 using std::atomic_fetch_xor;
89 using std::atomic_fetch_xor_explicit;
90 using std::atomic_fetch_and;
91 using std::atomic_fetch_and_explicit;
92 using std::atomic_thread_fence;
93 using std::atomic_signal_fence;
95 using std::memory_order;
96 using std::memory_order_relaxed;
97 using std::memory_order_consume;
98 using std::memory_order_acquire;
99 using std::memory_order_release;
100 using std::memory_order_acq_rel;
101 using std::memory_order_seq_cst;
103 using std::atomic_bool;
104 using std::atomic_char;
105 using std::atomic_schar;
106 using std::atomic_uchar;
107 using std::atomic_short;
108 using std::atomic_ushort;
109 using std::atomic_int;
110 using std::atomic_uint;
111 using std::atomic_long;
112 using std::atomic_ulong;
113 using std::atomic_llong;
114 using std::atomic_ullong;
115 using std::atomic_char16_t;
116 using std::atomic_char32_t;
117 using std::atomic_wchar_t;
118 using std::atomic_int_least8_t;
119 using std::atomic_uint_least8_t;
120 using std::atomic_int_least16_t;
121 using std::atomic_uint_least16_t;
122 using std::atomic_int_least32_t;
123 using std::atomic_uint_least32_t;
124 using std::atomic_int_least64_t;
125 using std::atomic_uint_least64_t;
126 using std::atomic_int_fast8_t;
127 using std::atomic_uint_fast8_t;
128 using std::atomic_int_fast16_t;
129 using std::atomic_uint_fast16_t;
130 using std::atomic_int_fast32_t;
131 using std::atomic_uint_fast32_t;
132 using std::atomic_int_fast64_t;
133 using std::atomic_uint_fast64_t;
134 using std::atomic_intptr_t;
135 using std::atomic_uintptr_t;
136 using std::atomic_size_t;
137 using std::atomic_ptrdiff_t;
138 using std::atomic_intmax_t;
139 using std::atomic_uintmax_t;
141 #else /* <atomic> unavailable, possibly because this is C, not C++ */
143 #include <sys/types.h>
144 #include <stdbool.h>
146 /*
147  * C: Do it ourselves.
148  * Note that the runtime representation defined here should be compatible
149  * with the C++ one, i.e. an _Atomic(T) needs to contain the same
150  * bits as a T.
151  */
153 #include <stddef.h>  /* For ptrdiff_t.                          */
154 #include <stdint.h>  /* TODO: Should pollute namespace less.    */
155 #if __STDC_VERSION__ >= 201112L
156 # include <uchar.h>  /* For char16_t and char32_t.              */
157 #endif
159 #ifdef __clang__
160 # if __has_extension(c_atomic) || __has_extension(cxx_atomic)
161 #  define       __CLANG_ATOMICS
162 # else
163 #  error "stdatomic.h does not support your compiler"
164 # endif
165 # if __has_builtin(__sync_swap)
166 #  define __HAS_BUILTIN_SYNC_SWAP
167 # endif
168 #else
169 # if __GNUC_PREREQ(4, 7)
170 #  define       __GNUC_ATOMICS
171 # else
172 #  define       __SYNC_ATOMICS
173 #  ifdef __cplusplus
174 #   define       __ATOMICS_AVOID_DOT_INIT
175 #  endif
176 # endif
177 #endif
179 /*
180  * 7.17.1 Atomic lock-free macros.
181  */
183 #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE
184 #define ATOMIC_BOOL_LOCK_FREE           __GCC_ATOMIC_BOOL_LOCK_FREE
185 #elif defined(__SYNC_ATOMICS)
186 #define ATOMIC_BOOL_LOCK_FREE           2 /* For all modern platforms */
187 #endif
188 #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE
189 #define ATOMIC_CHAR_LOCK_FREE           __GCC_ATOMIC_CHAR_LOCK_FREE
190 #elif defined(__SYNC_ATOMICS)
191 #define ATOMIC_CHAR_LOCK_FREE           2
192 #endif
193 #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE
194 #define ATOMIC_CHAR16_T_LOCK_FREE       __GCC_ATOMIC_CHAR16_T_LOCK_FREE
195 #elif defined(__SYNC_ATOMICS)
196 #define ATOMIC_CHAR16_T_LOCK_FREE       2
197 #endif
198 #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE
199 #define ATOMIC_CHAR32_T_LOCK_FREE       __GCC_ATOMIC_CHAR32_T_LOCK_FREE
200 #elif defined(__SYNC_ATOMICS)
201 #define ATOMIC_CHAR32_T_LOCK_FREE       2
202 #endif
203 #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE
204 #define ATOMIC_WCHAR_T_LOCK_FREE        __GCC_ATOMIC_WCHAR_T_LOCK_FREE
205 #elif defined(__SYNC_ATOMICS)
206 #define ATOMIC_WCHAR_T_LOCK_FREE        2
207 #endif
208 #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE
209 #define ATOMIC_SHORT_LOCK_FREE          __GCC_ATOMIC_SHORT_LOCK_FREE
210 #elif defined(__SYNC_ATOMICS)
211 #define ATOMIC_SHORT_LOCK_FREE          2
212 #endif
213 #ifdef __GCC_ATOMIC_INT_LOCK_FREE
214 #define ATOMIC_INT_LOCK_FREE            __GCC_ATOMIC_INT_LOCK_FREE
215 #elif defined(__SYNC_ATOMICS)
216 #define ATOMIC_INT_LOCK_FREE            2
217 #endif
218 #ifdef __GCC_ATOMIC_LONG_LOCK_FREE
219 #define ATOMIC_LONG_LOCK_FREE           __GCC_ATOMIC_LONG_LOCK_FREE
220 #elif defined(__SYNC_ATOMICS)
221 #define ATOMIC_LONG_LOCK_FREE           2
222 #endif
223 #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE
224 #define ATOMIC_LLONG_LOCK_FREE          __GCC_ATOMIC_LLONG_LOCK_FREE
225 #elif defined(__SYNC_ATOMICS)
226 #define ATOMIC_LLONG_LOCK_FREE          1 /* maybe */
227 #endif
228 #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE
229 #define ATOMIC_POINTER_LOCK_FREE        __GCC_ATOMIC_POINTER_LOCK_FREE
230 #elif defined(__SYNC_ATOMICS)
231 #define ATOMIC_POINTER_LOCK_FREE        2
232 #endif
234 /*
235  * 7.17.2 Initialization.
236  */
238 #if defined(__CLANG_ATOMICS)
239 #define ATOMIC_VAR_INIT(value)          (value)
240 #define atomic_init(obj, value)         __c11_atomic_init(obj, value)
241 #else
242 #ifdef __ATOMICS_AVOID_DOT_INIT
243 #define ATOMIC_VAR_INIT(value)          { value }
244 #else
245 #define ATOMIC_VAR_INIT(value)          { .__val = (value) }
246 #endif
247 #define atomic_init(obj, value)         ((void)((obj)->__val = (value)))
248 #endif
250 /*
251  * Clang and recent GCC both provide predefined macros for the memory
252  * orderings.  If we are using a compiler that doesn't define them, use the
253  * clang values - these will be ignored in the fallback path.
254  */
256 #ifndef __ATOMIC_RELAXED
257 #define __ATOMIC_RELAXED                0
258 #endif
259 #ifndef __ATOMIC_CONSUME
260 #define __ATOMIC_CONSUME                1
261 #endif
262 #ifndef __ATOMIC_ACQUIRE
263 #define __ATOMIC_ACQUIRE                2
264 #endif
265 #ifndef __ATOMIC_RELEASE
266 #define __ATOMIC_RELEASE                3
267 #endif
268 #ifndef __ATOMIC_ACQ_REL
269 #define __ATOMIC_ACQ_REL                4
270 #endif
271 #ifndef __ATOMIC_SEQ_CST
272 #define __ATOMIC_SEQ_CST                5
273 #endif
275 /*
276  * 7.17.3 Order and consistency.
277  *
278  * The memory_order_* constants that denote the barrier behaviour of the
279  * atomic operations.
280  * The enum values must be identical to those used by the
281  * C++ <atomic> header.
282  */
284 typedef enum {
285         memory_order_relaxed = __ATOMIC_RELAXED,
286         memory_order_consume = __ATOMIC_CONSUME,
287         memory_order_acquire = __ATOMIC_ACQUIRE,
288         memory_order_release = __ATOMIC_RELEASE,
289         memory_order_acq_rel = __ATOMIC_ACQ_REL,
290         memory_order_seq_cst = __ATOMIC_SEQ_CST
291 } memory_order;
293 /*
294  * 7.17.4 Fences.
295  */
297 static __inline void
298 atomic_thread_fence(memory_order __order __attribute__((unused)))
301 #ifdef __CLANG_ATOMICS
302         __c11_atomic_thread_fence(__order);
303 #elif defined(__GNUC_ATOMICS)
304         __atomic_thread_fence(__order);
305 #else
306         __sync_synchronize();
307 #endif
310 static __inline void
311 atomic_signal_fence(memory_order __order __attribute__((unused)))
314 #ifdef __CLANG_ATOMICS
315         __c11_atomic_signal_fence(__order);
316 #elif defined(__GNUC_ATOMICS)
317         __atomic_signal_fence(__order);
318 #else
319         __asm volatile ("" ::: "memory");
320 #endif
323 /*
324  * 7.17.5 Lock-free property.
325  */
327 #if defined(_KERNEL)
328 /* Atomics in kernelspace are always lock-free. */
329 #define atomic_is_lock_free(obj) \
330         ((void)(obj), (_Bool)1)
331 #elif defined(__CLANG_ATOMICS)
332 #define atomic_is_lock_free(obj) \
333         __c11_atomic_is_lock_free(sizeof(*(obj)))
334 #elif defined(__GNUC_ATOMICS)
335 #define atomic_is_lock_free(obj) \
336         __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val)
337 #else
338 #define atomic_is_lock_free(obj) \
339         ((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
340 #endif
342 /*
343  * 7.17.6 Atomic integer types.
344  */
346 #ifndef __CLANG_ATOMICS
347 /*
348  * No native support for _Atomic(). Place object in structure to prevent
349  * most forms of direct non-atomic access.
350  */
351 #define _Atomic(T)              struct { T volatile __val; }
352 #endif
354 typedef _Atomic(bool)                   atomic_bool;
355 typedef _Atomic(char)                   atomic_char;
356 typedef _Atomic(signed char)            atomic_schar;
357 typedef _Atomic(unsigned char)          atomic_uchar;
358 typedef _Atomic(short)                  atomic_short;
359 typedef _Atomic(unsigned short)         atomic_ushort;
360 typedef _Atomic(int)                    atomic_int;
361 typedef _Atomic(unsigned int)           atomic_uint;
362 typedef _Atomic(long)                   atomic_long;
363 typedef _Atomic(unsigned long)          atomic_ulong;
364 typedef _Atomic(long long)              atomic_llong;
365 typedef _Atomic(unsigned long long)     atomic_ullong;
366 #if __STDC_VERSION__ >= 201112L || __cplusplus >= 201103L
367   typedef _Atomic(char16_t)             atomic_char16_t;
368   typedef _Atomic(char32_t)             atomic_char32_t;
369 #endif
370 typedef _Atomic(wchar_t)                atomic_wchar_t;
371 typedef _Atomic(int_least8_t)           atomic_int_least8_t;
372 typedef _Atomic(uint_least8_t)  atomic_uint_least8_t;
373 typedef _Atomic(int_least16_t)  atomic_int_least16_t;
374 typedef _Atomic(uint_least16_t) atomic_uint_least16_t;
375 typedef _Atomic(int_least32_t)  atomic_int_least32_t;
376 typedef _Atomic(uint_least32_t) atomic_uint_least32_t;
377 typedef _Atomic(int_least64_t)  atomic_int_least64_t;
378 typedef _Atomic(uint_least64_t) atomic_uint_least64_t;
379 typedef _Atomic(int_fast8_t)            atomic_int_fast8_t;
380 typedef _Atomic(uint_fast8_t)           atomic_uint_fast8_t;
381 typedef _Atomic(int_fast16_t)           atomic_int_fast16_t;
382 typedef _Atomic(uint_fast16_t)  atomic_uint_fast16_t;
383 typedef _Atomic(int_fast32_t)           atomic_int_fast32_t;
384 typedef _Atomic(uint_fast32_t)  atomic_uint_fast32_t;
385 typedef _Atomic(int_fast64_t)           atomic_int_fast64_t;
386 typedef _Atomic(uint_fast64_t)  atomic_uint_fast64_t;
387 typedef _Atomic(intptr_t)               atomic_intptr_t;
388 typedef _Atomic(uintptr_t)              atomic_uintptr_t;
389 typedef _Atomic(size_t)         atomic_size_t;
390 typedef _Atomic(ptrdiff_t)              atomic_ptrdiff_t;
391 typedef _Atomic(intmax_t)               atomic_intmax_t;
392 typedef _Atomic(uintmax_t)              atomic_uintmax_t;
394 /*
395  * 7.17.7 Operations on atomic types.
396  */
398 /*
399  * Compiler-specific operations.
400  */
402 #if defined(__CLANG_ATOMICS)
403 #define atomic_compare_exchange_strong_explicit(object, expected,       \
404     desired, success, failure)                                          \
405         __c11_atomic_compare_exchange_strong(object, expected, desired, \
406             success, failure)
407 #define atomic_compare_exchange_weak_explicit(object, expected,         \
408     desired, success, failure)                                          \
409         __c11_atomic_compare_exchange_weak(object, expected, desired,   \
410             success, failure)
411 #define atomic_exchange_explicit(object, desired, order)                \
412         __c11_atomic_exchange(object, desired, order)
413 #define atomic_fetch_add_explicit(object, operand, order)               \
414         __c11_atomic_fetch_add(object, operand, order)
415 #define atomic_fetch_and_explicit(object, operand, order)               \
416         __c11_atomic_fetch_and(object, operand, order)
417 #define atomic_fetch_or_explicit(object, operand, order)                \
418         __c11_atomic_fetch_or(object, operand, order)
419 #define atomic_fetch_sub_explicit(object, operand, order)               \
420         __c11_atomic_fetch_sub(object, operand, order)
421 #define atomic_fetch_xor_explicit(object, operand, order)               \
422         __c11_atomic_fetch_xor(object, operand, order)
423 #define atomic_load_explicit(object, order)                             \
424         __c11_atomic_load(object, order)
425 #define atomic_store_explicit(object, desired, order)                   \
426         __c11_atomic_store(object, desired, order)
427 #elif defined(__GNUC_ATOMICS)
428 #define atomic_compare_exchange_strong_explicit(object, expected,       \
429     desired, success, failure)                                          \
430         __atomic_compare_exchange_n(&(object)->__val, expected,         \
431             desired, 0, success, failure)
432 #define atomic_compare_exchange_weak_explicit(object, expected,         \
433     desired, success, failure)                                          \
434         __atomic_compare_exchange_n(&(object)->__val, expected,         \
435             desired, 1, success, failure)
436 #define atomic_exchange_explicit(object, desired, order)                \
437         __atomic_exchange_n(&(object)->__val, desired, order)
438 #define atomic_fetch_add_explicit(object, operand, order)               \
439         __atomic_fetch_add(&(object)->__val, operand, order)
440 #define atomic_fetch_and_explicit(object, operand, order)               \
441         __atomic_fetch_and(&(object)->__val, operand, order)
442 #define atomic_fetch_or_explicit(object, operand, order)                \
443         __atomic_fetch_or(&(object)->__val, operand, order)
444 #define atomic_fetch_sub_explicit(object, operand, order)               \
445         __atomic_fetch_sub(&(object)->__val, operand, order)
446 #define atomic_fetch_xor_explicit(object, operand, order)               \
447         __atomic_fetch_xor(&(object)->__val, operand, order)
448 #define atomic_load_explicit(object, order)                             \
449         __atomic_load_n(&(object)->__val, order)
450 #define atomic_store_explicit(object, desired, order)                   \
451         __atomic_store_n(&(object)->__val, desired, order)
452 #else
453 #define __atomic_apply_stride(object, operand) \
454         (((__typeof__((object)->__val))0) + (operand))
455 #define atomic_compare_exchange_strong_explicit(object, expected,       \
456     desired, success, failure)  __extension__ ({                        \
457         __typeof__(expected) __ep = (expected);                         \
458         __typeof__(*__ep) __e = *__ep;                                  \
459         (void)(success); (void)(failure);                               \
460         (bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val,   \
461             __e, desired)) == __e);                                     \
462 })
463 #define atomic_compare_exchange_weak_explicit(object, expected,         \
464     desired, success, failure)                                          \
465         atomic_compare_exchange_strong_explicit(object, expected,       \
466                 desired, success, failure)
467 #ifdef __HAS_BUILTIN_SYNC_SWAP
468 /* Clang provides a full-barrier atomic exchange - use it if available. */
469 #define atomic_exchange_explicit(object, desired, order)                \
470         ((void)(order), __sync_swap(&(object)->__val, desired))
471 #else
472 /*
473  * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
474  * practice it is usually a full barrier) so we need an explicit barrier before
475  * it.
476  */
477 #define atomic_exchange_explicit(object, desired, order)                \
478 __extension__ ({                                                        \
479         __typeof__(object) __o = (object);                              \
480         __typeof__(desired) __d = (desired);                            \
481         (void)(order);                                                  \
482         __sync_synchronize();                                           \
483         __sync_lock_test_and_set(&(__o)->__val, __d);                   \
484 })
485 #endif
486 #define atomic_fetch_add_explicit(object, operand, order)               \
487         ((void)(order), __sync_fetch_and_add(&(object)->__val,          \
488             __atomic_apply_stride(object, operand)))
489 #define atomic_fetch_and_explicit(object, operand, order)               \
490         ((void)(order), __sync_fetch_and_and(&(object)->__val, operand))
491 #define atomic_fetch_or_explicit(object, operand, order)                \
492         ((void)(order), __sync_fetch_and_or(&(object)->__val, operand))
493 #define atomic_fetch_sub_explicit(object, operand, order)               \
494         ((void)(order), __sync_fetch_and_sub(&(object)->__val,          \
495             __atomic_apply_stride(object, operand)))
496 #define atomic_fetch_xor_explicit(object, operand, order)               \
497         ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))
498 #define atomic_load_explicit(object, order)                             \
499         ((void)(order), __sync_fetch_and_add(&(object)->__val, 0))
500 #define atomic_store_explicit(object, desired, order)                   \
501         ((void)atomic_exchange_explicit(object, desired, order))
502 #endif
504 /*
505  * Convenience functions.
506  *
507  * Don't provide these in kernel space. In kernel space, we should be
508  * disciplined enough to always provide explicit barriers.
509  */
511 #ifndef _KERNEL
512 #define atomic_compare_exchange_strong(object, expected, desired)       \
513         atomic_compare_exchange_strong_explicit(object, expected,       \
514             desired, memory_order_seq_cst, memory_order_seq_cst)
515 #define atomic_compare_exchange_weak(object, expected, desired)         \
516         atomic_compare_exchange_weak_explicit(object, expected,         \
517             desired, memory_order_seq_cst, memory_order_seq_cst)
518 #define atomic_exchange(object, desired)                                \
519         atomic_exchange_explicit(object, desired, memory_order_seq_cst)
520 #define atomic_fetch_add(object, operand)                               \
521         atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
522 #define atomic_fetch_and(object, operand)                               \
523         atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
524 #define atomic_fetch_or(object, operand)                                \
525         atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
526 #define atomic_fetch_sub(object, operand)                               \
527         atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
528 #define atomic_fetch_xor(object, operand)                               \
529         atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
530 #define atomic_load(object)                                             \
531         atomic_load_explicit(object, memory_order_seq_cst)
532 #define atomic_store(object, desired)                                   \
533         atomic_store_explicit(object, desired, memory_order_seq_cst)
534 #endif /* !_KERNEL */
536 /*
537  * 7.17.8 Atomic flag type and operations.
538  *
539  * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some
540  * kind of compiler built-in type we could use?
541  */
543 typedef struct {
544         atomic_bool     __flag;
545 } atomic_flag;
547 #define ATOMIC_FLAG_INIT                { ATOMIC_VAR_INIT(false) }
549 static __inline bool
550 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object,
551     memory_order __order)
553         return (atomic_exchange_explicit(&__object->__flag, 1, __order));
556 static __inline void
557 atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order)
560         atomic_store_explicit(&__object->__flag, 0, __order);
563 #ifndef _KERNEL
564 static __inline bool
565 atomic_flag_test_and_set(volatile atomic_flag *__object)
568         return (atomic_flag_test_and_set_explicit(__object,
569             memory_order_seq_cst));
572 static __inline void
573 atomic_flag_clear(volatile atomic_flag *__object)
576         atomic_flag_clear_explicit(__object, memory_order_seq_cst);
578 #endif /* !_KERNEL */
580 #endif /* <atomic> unavailable */
582 #endif /* !_STDATOMIC_H_ */