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#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__ && ... */ 41 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 53 54#ifdef _STDATOMIC_HAVE_ATOMIC 55 56/* We have a usable C++ <atomic>; use it instead. */ 57 58#include <atomic> 59 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. */ 67 68#define _Atomic(t) std::atomic<t> 69 70using std::atomic_is_lock_free; 71using std::atomic_init; 72using std::atomic_store; 73using std::atomic_store_explicit; 74using std::atomic_load; 75using std::atomic_load_explicit; 76using std::atomic_exchange; 77using std::atomic_exchange_explicit; 78using std::atomic_compare_exchange_strong; 79using std::atomic_compare_exchange_strong_explicit; 80using std::atomic_compare_exchange_weak; 81using std::atomic_compare_exchange_weak_explicit; 82using std::atomic_fetch_add; 83using std::atomic_fetch_add_explicit; 84using std::atomic_fetch_sub; 85using std::atomic_fetch_sub_explicit; 86using std::atomic_fetch_or; 87using std::atomic_fetch_or_explicit; 88using std::atomic_fetch_xor; 89using std::atomic_fetch_xor_explicit; 90using std::atomic_fetch_and; 91using std::atomic_fetch_and_explicit; 92using std::atomic_thread_fence; 93using std::atomic_signal_fence; 94 95using std::memory_order; 96using std::memory_order_relaxed; 97using std::memory_order_consume; 98using std::memory_order_acquire; 99using std::memory_order_release; 100using std::memory_order_acq_rel; 101using std::memory_order_seq_cst; 102 103using std::atomic_bool; 104using std::atomic_char; 105using std::atomic_schar; 106using std::atomic_uchar; 107using std::atomic_short; 108using std::atomic_ushort; 109using std::atomic_int; 110using std::atomic_uint; 111using std::atomic_long; 112using std::atomic_ulong; 113using std::atomic_llong; 114using std::atomic_ullong; 115using std::atomic_char16_t; 116using std::atomic_char32_t; 117using std::atomic_wchar_t; 118using std::atomic_int_least8_t; 119using std::atomic_uint_least8_t; 120using std::atomic_int_least16_t; 121using std::atomic_uint_least16_t; 122using std::atomic_int_least32_t; 123using std::atomic_uint_least32_t; 124using std::atomic_int_least64_t; 125using std::atomic_uint_least64_t; 126using std::atomic_int_fast8_t; 127using std::atomic_uint_fast8_t; 128using std::atomic_int_fast16_t; 129using std::atomic_uint_fast16_t; 130using std::atomic_int_fast32_t; 131using std::atomic_uint_fast32_t; 132using std::atomic_int_fast64_t; 133using std::atomic_uint_fast64_t; 134using std::atomic_intptr_t; 135using std::atomic_uintptr_t; 136using std::atomic_size_t; 137using std::atomic_ptrdiff_t; 138using std::atomic_intmax_t; 139using std::atomic_uintmax_t; 140 141#else /* <atomic> unavailable, possibly because this is C, not C++ */ 142 143#include <sys/types.h> 144#include <stdbool.h> 145 146/* 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 */ 152 153#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 158 159#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 178 179/* 180 * 7.17.1 Atomic lock-free macros. 181 */ 182 183#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 233 234/* 235 * 7.17.2 Initialization. 236 */ 237 238#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 249 250/* 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 */ 255 256#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 274 275/* 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 */ 283 284typedef 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; 292 293/* 294 * 7.17.4 Fences. 295 */ 296 297static __inline void 298atomic_thread_fence(memory_order __order __attribute__((unused))) 299{ 300 301#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 308} 309 310static __inline void 311atomic_signal_fence(memory_order __order __attribute__((unused))) 312{ 313 314#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 321} 322 323/* 324 * 7.17.5 Lock-free property. 325 */ 326 327#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 341 342/* 343 * 7.17.6 Atomic integer types. 344 */ 345 346#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 353 354typedef _Atomic(bool) atomic_bool; 355typedef _Atomic(char) atomic_char; 356typedef _Atomic(signed char) atomic_schar; 357typedef _Atomic(unsigned char) atomic_uchar; 358typedef _Atomic(short) atomic_short; 359typedef _Atomic(unsigned short) atomic_ushort; 360typedef _Atomic(int) atomic_int; 361typedef _Atomic(unsigned int) atomic_uint; 362typedef _Atomic(long) atomic_long; 363typedef _Atomic(unsigned long) atomic_ulong; 364typedef _Atomic(long long) atomic_llong; 365typedef _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 370typedef _Atomic(wchar_t) atomic_wchar_t; 371typedef _Atomic(int_least8_t) atomic_int_least8_t; 372typedef _Atomic(uint_least8_t) atomic_uint_least8_t; 373typedef _Atomic(int_least16_t) atomic_int_least16_t; 374typedef _Atomic(uint_least16_t) atomic_uint_least16_t; 375typedef _Atomic(int_least32_t) atomic_int_least32_t; 376typedef _Atomic(uint_least32_t) atomic_uint_least32_t; 377typedef _Atomic(int_least64_t) atomic_int_least64_t; 378typedef _Atomic(uint_least64_t) atomic_uint_least64_t; 379typedef _Atomic(int_fast8_t) atomic_int_fast8_t; 380typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t; 381typedef _Atomic(int_fast16_t) atomic_int_fast16_t; 382typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t; 383typedef _Atomic(int_fast32_t) atomic_int_fast32_t; 384typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t; 385typedef _Atomic(int_fast64_t) atomic_int_fast64_t; 386typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t; 387typedef _Atomic(intptr_t) atomic_intptr_t; 388typedef _Atomic(uintptr_t) atomic_uintptr_t; 389typedef _Atomic(size_t) atomic_size_t; 390typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t; 391typedef _Atomic(intmax_t) atomic_intmax_t; 392typedef _Atomic(uintmax_t) atomic_uintmax_t; 393 394/* 395 * 7.17.7 Operations on atomic types. 396 */ 397 398/* 399 * Compiler-specific operations. 400 */ 401 402#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 503 504/* 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 */ 510 511#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 */ 535 536/* 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 */ 542 543typedef struct { 544 atomic_bool __flag; 545} atomic_flag; 546 547#define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(false) } 548 549static __inline bool 550atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 551 memory_order __order) 552{ 553 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 554} 555 556static __inline void 557atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) 558{ 559 560 atomic_store_explicit(&__object->__flag, 0, __order); 561} 562 563#ifndef _KERNEL 564static __inline bool 565atomic_flag_test_and_set(volatile atomic_flag *__object) 566{ 567 568 return (atomic_flag_test_and_set_explicit(__object, 569 memory_order_seq_cst)); 570} 571 572static __inline void 573atomic_flag_clear(volatile atomic_flag *__object) 574{ 575 576 atomic_flag_clear_explicit(__object, memory_order_seq_cst); 577} 578#endif /* !_KERNEL */ 579 580#endif /* <atomic> unavailable */ 581 582#endif /* !_STDATOMIC_H_ */ 583