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 */ 29 30#ifndef _STDATOMIC_H_ 31#define _STDATOMIC_H_ 32 33#include <sys/cdefs.h> 34 35 36#if defined(__cplusplus) && __cplusplus >= 201103L && defined(_USING_LIBCXX) 37# ifdef __clang__ 38# if __has_feature(cxx_atomic) 39# define _STDATOMIC_HAVE_ATOMIC 40# endif 41# else /* gcc */ 42# if __GNUC_PREREQ(4, 7) 43# define _STDATOMIC_HAVE_ATOMIC 44# endif 45# endif 46#endif 47 48#ifdef _STDATOMIC_HAVE_ATOMIC 49 50/* We have a usable C++ <atomic>; use it instead. */ 51 52#include <atomic> 53 54#undef _Atomic 55 /* Also defined by <atomic> for gcc. But not used in macros. */ 56 /* Also a clang intrinsic. */ 57 /* Should not be used by client code before this file is */ 58 /* included. The definitions in <atomic> themselves see */ 59 /* the old definition, as they should. */ 60 /* Client code sees the following definition. */ 61 62#define _Atomic(t) std::atomic<t> 63 64using std::atomic_is_lock_free; 65using std::atomic_init; 66using std::atomic_store; 67using std::atomic_store_explicit; 68using std::atomic_load; 69using std::atomic_load_explicit; 70using std::atomic_exchange; 71using std::atomic_exchange_explicit; 72using std::atomic_compare_exchange_strong; 73using std::atomic_compare_exchange_strong_explicit; 74using std::atomic_compare_exchange_weak; 75using std::atomic_compare_exchange_weak_explicit; 76using std::atomic_fetch_add; 77using std::atomic_fetch_add_explicit; 78using std::atomic_fetch_sub; 79using std::atomic_fetch_sub_explicit; 80using std::atomic_fetch_or; 81using std::atomic_fetch_or_explicit; 82using std::atomic_fetch_xor; 83using std::atomic_fetch_xor_explicit; 84using std::atomic_fetch_and; 85using std::atomic_fetch_and_explicit; 86using std::atomic_thread_fence; 87using std::atomic_signal_fence; 88 89using std::memory_order; 90using std::memory_order_relaxed; 91using std::memory_order_consume; 92using std::memory_order_acquire; 93using std::memory_order_release; 94using std::memory_order_acq_rel; 95using std::memory_order_seq_cst; 96 97using std::atomic_bool; 98using std::atomic_char; 99using std::atomic_schar; 100using std::atomic_uchar; 101using std::atomic_short; 102using std::atomic_ushort; 103using std::atomic_int; 104using std::atomic_uint; 105using std::atomic_long; 106using std::atomic_ulong; 107using std::atomic_llong; 108using std::atomic_ullong; 109using std::atomic_char16_t; 110using std::atomic_char32_t; 111using std::atomic_wchar_t; 112using std::atomic_int_least8_t; 113using std::atomic_uint_least8_t; 114using std::atomic_int_least16_t; 115using std::atomic_uint_least16_t; 116using std::atomic_int_least32_t; 117using std::atomic_uint_least32_t; 118using std::atomic_int_least64_t; 119using std::atomic_uint_least64_t; 120using std::atomic_int_fast8_t; 121using std::atomic_uint_fast8_t; 122using std::atomic_int_fast16_t; 123using std::atomic_uint_fast16_t; 124using std::atomic_int_fast32_t; 125using std::atomic_uint_fast32_t; 126using std::atomic_int_fast64_t; 127using std::atomic_uint_fast64_t; 128using std::atomic_intptr_t; 129using std::atomic_uintptr_t; 130using std::atomic_size_t; 131using std::atomic_ptrdiff_t; 132using std::atomic_intmax_t; 133using std::atomic_uintmax_t; 134 135#else /* <atomic> unavailable, possibly because this is C, not C++ */ 136 137#include <sys/types.h> 138#include <stdbool.h> 139 140/* 141 * C: Do it ourselves. 142 * Note that the runtime representation defined here should be compatible 143 * with the C++ one, i.e. an _Atomic(T) needs to contain the same 144 * bits as a T. 145 */ 146 147#include <stddef.h> /* For ptrdiff_t. */ 148#include <stdint.h> /* TODO: Should pollute namespace less. */ 149#if __STDC_VERSION__ >= 201112L 150# include <uchar.h> /* For char16_t and char32_t. */ 151#endif 152 153#ifdef __clang__ 154# if __has_extension(c_atomic) || __has_extension(cxx_atomic) 155# define __CLANG_ATOMICS 156# else 157# error "stdatomic.h does not support your compiler" 158# endif 159# if __has_builtin(__sync_swap) 160# define __HAS_BUILTIN_SYNC_SWAP 161# endif 162#else 163# if __GNUC_PREREQ(4, 7) 164# define __GNUC_ATOMICS 165# else 166# define __SYNC_ATOMICS 167# ifdef __cplusplus 168# define __ATOMICS_AVOID_DOT_INIT 169# endif 170# endif 171#endif 172 173/* 174 * 7.17.1 Atomic lock-free macros. 175 */ 176 177#ifdef __GCC_ATOMIC_BOOL_LOCK_FREE 178#define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE 179#elif defined(__SYNC_ATOMICS) 180#define ATOMIC_BOOL_LOCK_FREE 2 /* For all modern platforms */ 181#endif 182#ifdef __GCC_ATOMIC_CHAR_LOCK_FREE 183#define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE 184#elif defined(__SYNC_ATOMICS) 185#define ATOMIC_CHAR_LOCK_FREE 2 186#endif 187#ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE 188#define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE 189#elif defined(__SYNC_ATOMICS) 190#define ATOMIC_CHAR16_T_LOCK_FREE 2 191#endif 192#ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE 193#define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE 194#elif defined(__SYNC_ATOMICS) 195#define ATOMIC_CHAR32_T_LOCK_FREE 2 196#endif 197#ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE 198#define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE 199#elif defined(__SYNC_ATOMICS) 200#define ATOMIC_WCHAR_T_LOCK_FREE 2 201#endif 202#ifdef __GCC_ATOMIC_SHORT_LOCK_FREE 203#define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE 204#elif defined(__SYNC_ATOMICS) 205#define ATOMIC_SHORT_LOCK_FREE 2 206#endif 207#ifdef __GCC_ATOMIC_INT_LOCK_FREE 208#define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE 209#elif defined(__SYNC_ATOMICS) 210#define ATOMIC_INT_LOCK_FREE 2 211#endif 212#ifdef __GCC_ATOMIC_LONG_LOCK_FREE 213#define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE 214#elif defined(__SYNC_ATOMICS) 215#define ATOMIC_LONG_LOCK_FREE 2 216#endif 217#ifdef __GCC_ATOMIC_LLONG_LOCK_FREE 218#define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE 219#elif defined(__SYNC_ATOMICS) 220#define ATOMIC_LLONG_LOCK_FREE 1 /* maybe */ 221#endif 222#ifdef __GCC_ATOMIC_POINTER_LOCK_FREE 223#define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE 224#elif defined(__SYNC_ATOMICS) 225#define ATOMIC_POINTER_LOCK_FREE 2 226#endif 227 228/* 229 * 7.17.2 Initialization. 230 */ 231 232#if defined(__CLANG_ATOMICS) 233#define ATOMIC_VAR_INIT(value) (value) 234#define atomic_init(obj, value) __c11_atomic_init(obj, value) 235#else 236#ifdef __ATOMICS_AVOID_DOT_INIT 237#define ATOMIC_VAR_INIT(value) { value } 238#else 239#define ATOMIC_VAR_INIT(value) { .__val = (value) } 240#endif 241#define atomic_init(obj, value) ((void)((obj)->__val = (value))) 242#endif 243 244/* 245 * Clang and recent GCC both provide predefined macros for the memory 246 * orderings. If we are using a compiler that doesn't define them, use the 247 * clang values - these will be ignored in the fallback path. 248 */ 249 250#ifndef __ATOMIC_RELAXED 251#define __ATOMIC_RELAXED 0 252#endif 253#ifndef __ATOMIC_CONSUME 254#define __ATOMIC_CONSUME 1 255#endif 256#ifndef __ATOMIC_ACQUIRE 257#define __ATOMIC_ACQUIRE 2 258#endif 259#ifndef __ATOMIC_RELEASE 260#define __ATOMIC_RELEASE 3 261#endif 262#ifndef __ATOMIC_ACQ_REL 263#define __ATOMIC_ACQ_REL 4 264#endif 265#ifndef __ATOMIC_SEQ_CST 266#define __ATOMIC_SEQ_CST 5 267#endif 268 269/* 270 * 7.17.3 Order and consistency. 271 * 272 * The memory_order_* constants that denote the barrier behaviour of the 273 * atomic operations. 274 * The enum values must be identical to those used by the 275 * C++ <atomic> header. 276 */ 277 278typedef enum { 279 memory_order_relaxed = __ATOMIC_RELAXED, 280 memory_order_consume = __ATOMIC_CONSUME, 281 memory_order_acquire = __ATOMIC_ACQUIRE, 282 memory_order_release = __ATOMIC_RELEASE, 283 memory_order_acq_rel = __ATOMIC_ACQ_REL, 284 memory_order_seq_cst = __ATOMIC_SEQ_CST 285} memory_order; 286 287/* 288 * 7.17.4 Fences. 289 */ 290 291static __inline void 292atomic_thread_fence(memory_order __order __attribute__((unused))) 293{ 294 295#ifdef __CLANG_ATOMICS 296 __c11_atomic_thread_fence(__order); 297#elif defined(__GNUC_ATOMICS) 298 __atomic_thread_fence(__order); 299#else 300 __sync_synchronize(); 301#endif 302} 303 304static __inline void 305atomic_signal_fence(memory_order __order __attribute__((unused))) 306{ 307 308#ifdef __CLANG_ATOMICS 309 __c11_atomic_signal_fence(__order); 310#elif defined(__GNUC_ATOMICS) 311 __atomic_signal_fence(__order); 312#else 313 __asm volatile ("" ::: "memory"); 314#endif 315} 316 317/* 318 * 7.17.5 Lock-free property. 319 */ 320 321#if defined(_KERNEL) 322/* Atomics in kernelspace are always lock-free. */ 323#define atomic_is_lock_free(obj) \ 324 ((void)(obj), (_Bool)1) 325#elif defined(__CLANG_ATOMICS) 326#define atomic_is_lock_free(obj) \ 327 __c11_atomic_is_lock_free(sizeof(*(obj))) 328#elif defined(__GNUC_ATOMICS) 329#define atomic_is_lock_free(obj) \ 330 __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val) 331#else 332#define atomic_is_lock_free(obj) \ 333 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *)) 334#endif 335 336/* 337 * 7.17.6 Atomic integer types. 338 */ 339 340#ifndef __CLANG_ATOMICS 341/* 342 * No native support for _Atomic(). Place object in structure to prevent 343 * most forms of direct non-atomic access. 344 */ 345#define _Atomic(T) struct { T volatile __val; } 346#endif 347 348typedef _Atomic(bool) atomic_bool; 349typedef _Atomic(char) atomic_char; 350typedef _Atomic(signed char) atomic_schar; 351typedef _Atomic(unsigned char) atomic_uchar; 352typedef _Atomic(short) atomic_short; 353typedef _Atomic(unsigned short) atomic_ushort; 354typedef _Atomic(int) atomic_int; 355typedef _Atomic(unsigned int) atomic_uint; 356typedef _Atomic(long) atomic_long; 357typedef _Atomic(unsigned long) atomic_ulong; 358typedef _Atomic(long long) atomic_llong; 359typedef _Atomic(unsigned long long) atomic_ullong; 360#if __STDC_VERSION__ >= 201112L || __cplusplus >= 201103L 361 typedef _Atomic(char16_t) atomic_char16_t; 362 typedef _Atomic(char32_t) atomic_char32_t; 363#endif 364typedef _Atomic(wchar_t) atomic_wchar_t; 365typedef _Atomic(int_least8_t) atomic_int_least8_t; 366typedef _Atomic(uint_least8_t) atomic_uint_least8_t; 367typedef _Atomic(int_least16_t) atomic_int_least16_t; 368typedef _Atomic(uint_least16_t) atomic_uint_least16_t; 369typedef _Atomic(int_least32_t) atomic_int_least32_t; 370typedef _Atomic(uint_least32_t) atomic_uint_least32_t; 371typedef _Atomic(int_least64_t) atomic_int_least64_t; 372typedef _Atomic(uint_least64_t) atomic_uint_least64_t; 373typedef _Atomic(int_fast8_t) atomic_int_fast8_t; 374typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t; 375typedef _Atomic(int_fast16_t) atomic_int_fast16_t; 376typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t; 377typedef _Atomic(int_fast32_t) atomic_int_fast32_t; 378typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t; 379typedef _Atomic(int_fast64_t) atomic_int_fast64_t; 380typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t; 381typedef _Atomic(intptr_t) atomic_intptr_t; 382typedef _Atomic(uintptr_t) atomic_uintptr_t; 383typedef _Atomic(size_t) atomic_size_t; 384typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t; 385typedef _Atomic(intmax_t) atomic_intmax_t; 386typedef _Atomic(uintmax_t) atomic_uintmax_t; 387 388/* 389 * 7.17.7 Operations on atomic types. 390 */ 391 392/* 393 * Compiler-specific operations. 394 */ 395 396#if defined(__CLANG_ATOMICS) 397#define atomic_compare_exchange_strong_explicit(object, expected, \ 398 desired, success, failure) \ 399 __c11_atomic_compare_exchange_strong(object, expected, desired, \ 400 success, failure) 401#define atomic_compare_exchange_weak_explicit(object, expected, \ 402 desired, success, failure) \ 403 __c11_atomic_compare_exchange_weak(object, expected, desired, \ 404 success, failure) 405#define atomic_exchange_explicit(object, desired, order) \ 406 __c11_atomic_exchange(object, desired, order) 407#define atomic_fetch_add_explicit(object, operand, order) \ 408 __c11_atomic_fetch_add(object, operand, order) 409#define atomic_fetch_and_explicit(object, operand, order) \ 410 __c11_atomic_fetch_and(object, operand, order) 411#define atomic_fetch_or_explicit(object, operand, order) \ 412 __c11_atomic_fetch_or(object, operand, order) 413#define atomic_fetch_sub_explicit(object, operand, order) \ 414 __c11_atomic_fetch_sub(object, operand, order) 415#define atomic_fetch_xor_explicit(object, operand, order) \ 416 __c11_atomic_fetch_xor(object, operand, order) 417#define atomic_load_explicit(object, order) \ 418 __c11_atomic_load(object, order) 419#define atomic_store_explicit(object, desired, order) \ 420 __c11_atomic_store(object, desired, order) 421#elif defined(__GNUC_ATOMICS) 422#define atomic_compare_exchange_strong_explicit(object, expected, \ 423 desired, success, failure) \ 424 __atomic_compare_exchange_n(&(object)->__val, expected, \ 425 desired, 0, success, failure) 426#define atomic_compare_exchange_weak_explicit(object, expected, \ 427 desired, success, failure) \ 428 __atomic_compare_exchange_n(&(object)->__val, expected, \ 429 desired, 1, success, failure) 430#define atomic_exchange_explicit(object, desired, order) \ 431 __atomic_exchange_n(&(object)->__val, desired, order) 432#define atomic_fetch_add_explicit(object, operand, order) \ 433 __atomic_fetch_add(&(object)->__val, operand, order) 434#define atomic_fetch_and_explicit(object, operand, order) \ 435 __atomic_fetch_and(&(object)->__val, operand, order) 436#define atomic_fetch_or_explicit(object, operand, order) \ 437 __atomic_fetch_or(&(object)->__val, operand, order) 438#define atomic_fetch_sub_explicit(object, operand, order) \ 439 __atomic_fetch_sub(&(object)->__val, operand, order) 440#define atomic_fetch_xor_explicit(object, operand, order) \ 441 __atomic_fetch_xor(&(object)->__val, operand, order) 442#define atomic_load_explicit(object, order) \ 443 __atomic_load_n(&(object)->__val, order) 444#define atomic_store_explicit(object, desired, order) \ 445 __atomic_store_n(&(object)->__val, desired, order) 446#else 447#define __atomic_apply_stride(object, operand) \ 448 (((__typeof__((object)->__val))0) + (operand)) 449#define atomic_compare_exchange_strong_explicit(object, expected, \ 450 desired, success, failure) __extension__ ({ \ 451 __typeof__(expected) __ep = (expected); \ 452 __typeof__(*__ep) __e = *__ep; \ 453 (void)(success); (void)(failure); \ 454 (bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \ 455 __e, desired)) == __e); \ 456}) 457#define atomic_compare_exchange_weak_explicit(object, expected, \ 458 desired, success, failure) \ 459 atomic_compare_exchange_strong_explicit(object, expected, \ 460 desired, success, failure) 461#ifdef __HAS_BUILTIN_SYNC_SWAP 462/* Clang provides a full-barrier atomic exchange - use it if available. */ 463#define atomic_exchange_explicit(object, desired, order) \ 464 ((void)(order), __sync_swap(&(object)->__val, desired)) 465#else 466/* 467 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in 468 * practice it is usually a full barrier) so we need an explicit barrier before 469 * it. 470 */ 471#define atomic_exchange_explicit(object, desired, order) \ 472__extension__ ({ \ 473 __typeof__(object) __o = (object); \ 474 __typeof__(desired) __d = (desired); \ 475 (void)(order); \ 476 __sync_synchronize(); \ 477 __sync_lock_test_and_set(&(__o)->__val, __d); \ 478}) 479#endif 480#define atomic_fetch_add_explicit(object, operand, order) \ 481 ((void)(order), __sync_fetch_and_add(&(object)->__val, \ 482 __atomic_apply_stride(object, operand))) 483#define atomic_fetch_and_explicit(object, operand, order) \ 484 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand)) 485#define atomic_fetch_or_explicit(object, operand, order) \ 486 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand)) 487#define atomic_fetch_sub_explicit(object, operand, order) \ 488 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \ 489 __atomic_apply_stride(object, operand))) 490#define atomic_fetch_xor_explicit(object, operand, order) \ 491 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand)) 492#define atomic_load_explicit(object, order) \ 493 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0)) 494#define atomic_store_explicit(object, desired, order) \ 495 ((void)atomic_exchange_explicit(object, desired, order)) 496#endif 497 498/* 499 * Convenience functions. 500 * 501 * Don't provide these in kernel space. In kernel space, we should be 502 * disciplined enough to always provide explicit barriers. 503 */ 504 505#ifndef _KERNEL 506#define atomic_compare_exchange_strong(object, expected, desired) \ 507 atomic_compare_exchange_strong_explicit(object, expected, \ 508 desired, memory_order_seq_cst, memory_order_seq_cst) 509#define atomic_compare_exchange_weak(object, expected, desired) \ 510 atomic_compare_exchange_weak_explicit(object, expected, \ 511 desired, memory_order_seq_cst, memory_order_seq_cst) 512#define atomic_exchange(object, desired) \ 513 atomic_exchange_explicit(object, desired, memory_order_seq_cst) 514#define atomic_fetch_add(object, operand) \ 515 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst) 516#define atomic_fetch_and(object, operand) \ 517 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst) 518#define atomic_fetch_or(object, operand) \ 519 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst) 520#define atomic_fetch_sub(object, operand) \ 521 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst) 522#define atomic_fetch_xor(object, operand) \ 523 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst) 524#define atomic_load(object) \ 525 atomic_load_explicit(object, memory_order_seq_cst) 526#define atomic_store(object, desired) \ 527 atomic_store_explicit(object, desired, memory_order_seq_cst) 528#endif /* !_KERNEL */ 529 530/* 531 * 7.17.8 Atomic flag type and operations. 532 * 533 * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some 534 * kind of compiler built-in type we could use? 535 */ 536 537typedef struct { 538 atomic_bool __flag; 539} atomic_flag; 540 541#define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(false) } 542 543static __inline bool 544atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 545 memory_order __order) 546{ 547 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 548} 549 550static __inline void 551atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) 552{ 553 554 atomic_store_explicit(&__object->__flag, 0, __order); 555} 556 557#ifndef _KERNEL 558static __inline bool 559atomic_flag_test_and_set(volatile atomic_flag *__object) 560{ 561 562 return (atomic_flag_test_and_set_explicit(__object, 563 memory_order_seq_cst)); 564} 565 566static __inline void 567atomic_flag_clear(volatile atomic_flag *__object) 568{ 569 570 atomic_flag_clear_explicit(__object, memory_order_seq_cst); 571} 572#endif /* !_KERNEL */ 573 574#endif /* <atomic> unavailable */ 575 576#endif /* !_STDATOMIC_H_ */ 577