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f9f20af9ed
- Evaluate the memory order argument in atomic_fetch_*_explicit macros. - Implement atomic_store_explicit using atomic_exchange_explicit instead of a plain assignment. Reviewed by: theraven MFC after: 2 weeks
328 lines
12 KiB
C
328 lines
12 KiB
C
/*-
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* Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org>
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* David Chisnall <theraven@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _STDATOMIC_H_
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#define _STDATOMIC_H_
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#include <sys/cdefs.h>
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#include <sys/_types.h>
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#if __has_extension(c_atomic) || __has_extension(cxx_atomic)
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#define __CLANG_ATOMICS
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#elif __GNUC_PREREQ__(4, 7)
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#define __GNUC_ATOMICS
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#elif !defined(__GNUC__)
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#error "stdatomic.h does not support your compiler"
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#endif
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#if !defined(__CLANG_ATOMICS)
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#define _Atomic(T) struct { volatile T __val; }
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#endif
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/*
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* 7.17.2 Initialization.
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*/
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#if defined(__CLANG_ATOMICS)
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#define ATOMIC_VAR_INIT(value) (value)
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#define atomic_init(obj, value) __c11_atomic_init(obj, value)
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#else
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#define ATOMIC_VAR_INIT(value) { .__val = (value) }
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#define atomic_init(obj, value) ((void)((obj)->__val = (value)))
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#endif
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/*
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* Clang and recent GCC both provide predefined macros for the memory
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* orderings. If we are using a compiler that doesn't define them, use the
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* clang values - these will be ignored in the fallback path.
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*/
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#ifndef __ATOMIC_RELAXED
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#define __ATOMIC_RELAXED 0
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#endif
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#ifndef __ATOMIC_CONSUME
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#define __ATOMIC_CONSUME 1
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#endif
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#ifndef __ATOMIC_ACQUIRE
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#define __ATOMIC_ACQUIRE 2
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#endif
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#ifndef __ATOMIC_RELEASE
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#define __ATOMIC_RELEASE 3
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#endif
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#ifndef __ATOMIC_ACQ_REL
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#define __ATOMIC_ACQ_REL 4
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#endif
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#ifndef __ATOMIC_SEQ_CST
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#define __ATOMIC_SEQ_CST 5
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#endif
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/*
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* 7.17.3 Order and consistency.
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*
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* The memory_order_* constants that denote the barrier behaviour of the
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* atomic operations.
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*/
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enum memory_order {
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memory_order_relaxed = __ATOMIC_RELAXED,
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memory_order_consume = __ATOMIC_CONSUME,
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memory_order_acquire = __ATOMIC_ACQUIRE,
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memory_order_release = __ATOMIC_RELEASE,
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memory_order_acq_rel = __ATOMIC_ACQ_REL,
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memory_order_seq_cst = __ATOMIC_SEQ_CST
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};
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/*
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* 7.17.4 Fences.
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*/
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#ifdef __CLANG_ATOMICS
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#define atomic_thread_fence(order) __c11_atomic_thread_fence(order)
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#define atomic_signal_fence(order) __c11_atomic_signal_fence(order)
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#elif defined(__GNUC_ATOMICS)
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#define atomic_thread_fence(order) __atomic_thread_fence(order)
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#define atomic_signal_fence(order) __atomic_signal_fence(order)
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#else
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#define atomic_thread_fence(order) ((void)(order), __sync_synchronize())
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#define atomic_signal_fence(order) __extension__ ({ \
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(void)(order); \
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__asm volatile ("" ::: "memory"); \
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(void)0; \
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})
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#endif
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/*
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* 7.17.5 Lock-free property.
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*/
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#if defined(__CLANG_ATOMICS) || defined(__GNUC_ATOMICS)
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#define atomic_is_lock_free(obj) \
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__atomic_is_lock_free(sizeof((obj)->__val), &(obj)->val)
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#else
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#define atomic_is_lock_free(obj) \
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((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
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#endif
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/*
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* 7.17.6 Atomic integer types.
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*/
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typedef _Atomic(_Bool) atomic_bool;
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typedef _Atomic(char) atomic_char;
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typedef _Atomic(signed char) atomic_schar;
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typedef _Atomic(unsigned char) atomic_uchar;
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typedef _Atomic(short) atomic_short;
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typedef _Atomic(unsigned short) atomic_ushort;
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typedef _Atomic(int) atomic_int;
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typedef _Atomic(unsigned int) atomic_uint;
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typedef _Atomic(long) atomic_long;
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typedef _Atomic(unsigned long) atomic_ulong;
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typedef _Atomic(long long) atomic_llong;
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typedef _Atomic(unsigned long long) atomic_ullong;
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#if 0
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typedef _Atomic(__char16_t) atomic_char16_t;
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typedef _Atomic(__char32_t) atomic_char32_t;
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#endif
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typedef _Atomic(__wchar_t) atomic_wchar_t;
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typedef _Atomic(__int_least8_t) atomic_int_least8_t;
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typedef _Atomic(__uint_least8_t) atomic_uint_least8_t;
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typedef _Atomic(__int_least16_t) atomic_int_least16_t;
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typedef _Atomic(__uint_least16_t) atomic_uint_least16_t;
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typedef _Atomic(__int_least32_t) atomic_int_least32_t;
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typedef _Atomic(__uint_least32_t) atomic_uint_least32_t;
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typedef _Atomic(__int_least64_t) atomic_int_least64_t;
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typedef _Atomic(__uint_least64_t) atomic_uint_least64_t;
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typedef _Atomic(__int_fast8_t) atomic_int_fast8_t;
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typedef _Atomic(__uint_fast8_t) atomic_uint_fast8_t;
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typedef _Atomic(__int_fast16_t) atomic_int_fast16_t;
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typedef _Atomic(__uint_fast16_t) atomic_uint_fast16_t;
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typedef _Atomic(__int_fast32_t) atomic_int_fast32_t;
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typedef _Atomic(__uint_fast32_t) atomic_uint_fast32_t;
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typedef _Atomic(__int_fast64_t) atomic_int_fast64_t;
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typedef _Atomic(__uint_fast64_t) atomic_uint_fast64_t;
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typedef _Atomic(__intptr_t) atomic_intptr_t;
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typedef _Atomic(__uintptr_t) atomic_uintptr_t;
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typedef _Atomic(__size_t) atomic_size_t;
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typedef _Atomic(__ptrdiff_t) atomic_ptrdiff_t;
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typedef _Atomic(__intmax_t) atomic_intmax_t;
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typedef _Atomic(__uintmax_t) atomic_uintmax_t;
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/*
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* 7.17.7 Operations on atomic types.
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*/
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/*
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* Compiler-specific operations.
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*/
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#if defined(__CLANG_ATOMICS)
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#define atomic_compare_exchange_strong_explicit(object, expected, \
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desired, success, failure) \
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__c11_atomic_compare_exchange_strong(object, expected, desired, \
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success, failure)
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#define atomic_compare_exchange_weak_explicit(object, expected, \
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desired, success, failure) \
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__c11_atomic_compare_exchange_weak(object, expected, desired, \
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success, failure)
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#define atomic_exchange_explicit(object, desired, order) \
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__c11_atomic_exchange(object, desired, order)
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#define atomic_fetch_add_explicit(object, operand, order) \
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__c11_atomic_fetch_add(object, operand, order)
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#define atomic_fetch_and_explicit(object, operand, order) \
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__c11_atomic_fetch_and(object, operand, order)
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#define atomic_fetch_or_explicit(object, operand, order) \
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__c11_atomic_fetch_or(object, operand, order)
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#define atomic_fetch_sub_explicit(object, operand, order) \
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__c11_atomic_fetch_sub(object, operand, order)
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#define atomic_fetch_xor_explicit(object, operand, order) \
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__c11_atomic_fetch_xor(object, operand, order)
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#define atomic_load_explicit(object, order) \
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__c11_atomic_load(object, order)
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#define atomic_store_explicit(object, desired, order) \
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__c11_atomic_store(object, desired, order)
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#elif defined(__GNUC_ATOMICS)
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#define atomic_compare_exchange_strong_explicit(object, expected, \
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desired, success, failure) \
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__atomic_compare_exchange_n(&(object)->__val, expected, \
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desired, 0, success, failure)
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#define atomic_compare_exchange_weak_explicit(object, expected, \
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desired, success, failure) \
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__atomic_compare_exchange_n(&(object)->__val, expected, \
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desired, 1, success, failure)
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#define atomic_exchange_explicit(object, desired, order) \
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__atomic_exchange_n(&(object)->__val, desired, order)
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#define atomic_fetch_add_explicit(object, operand, order) \
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__atomic_fetch_add(&(object)->__val, operand, order)
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#define atomic_fetch_and_explicit(object, operand, order) \
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__atomic_fetch_and(&(object)->__val, operand, order)
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#define atomic_fetch_or_explicit(object, operand, order) \
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__atomic_fetch_or(&(object)->__val, operand, order)
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#define atomic_fetch_sub_explicit(object, operand, order) \
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__atomic_fetch_sub(&(object)->__val, operand, order)
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#define atomic_fetch_xor_explicit(object, operand, order) \
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__atomic_fetch_xor(&(object)->__val, operand, order)
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#define atomic_load_explicit(object, order) \
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__atomic_load_n(&(object)->__val, order)
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#define atomic_store_explicit(object, desired, order) \
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__atomic_store_n(&(object)->__val, desired, order)
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#else
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#define atomic_compare_exchange_strong_explicit(object, expected, \
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desired, success, failure) __extension__ ({ \
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__typeof__(expected) __ep = (expected); \
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__typeof__(*__ep) __e = *__ep; \
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(void)(success); (void)(failure); \
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(*__ep = __sync_val_compare_and_swap(&(object)->__val, \
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__e, desired)) == __e; \
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})
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#define atomic_compare_exchange_weak_explicit(object, expected, \
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desired, success, failure) \
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atomic_compare_exchange_strong_explicit(object, expected, \
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desired, success, failure)
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#if __has_builtin(__sync_swap)
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/* Clang provides a full-barrier atomic exchange - use it if available. */
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#define atomic_exchange_explicit(object, desired, order) \
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((void)(order), __sync_swap(&(object)->__val, desired))
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#else
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/*
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* __sync_lock_test_and_set() is only an acquire barrier in theory (although in
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* practice it is usually a full barrier) so we need an explicit barrier before
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* it.
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*/
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#define atomic_exchange_explicit(object, desired, order) \
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__extension__ ({ \
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__typeof__(object) __o = (object); \
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__typeof__(desired) __d = (desired); \
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(void)(order); \
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__sync_synchronize(); \
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__sync_lock_test_and_set(&(__o)->__val, __d); \
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})
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#endif
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#define atomic_fetch_add_explicit(object, operand, order) \
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((void)(order), __sync_fetch_and_add(&(object)->__val, operand))
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#define atomic_fetch_and_explicit(object, operand, order) \
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((void)(order), __sync_fetch_and_and(&(object)->__val, operand))
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#define atomic_fetch_or_explicit(object, operand, order) \
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((void)(order), __sync_fetch_and_or(&(object)->__val, operand))
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#define atomic_fetch_sub_explicit(object, operand, order) \
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((void)(order), __sync_fetch_and_sub(&(object)->__val, operand))
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#define atomic_fetch_xor_explicit(object, operand, order) \
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((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))
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#define atomic_load_explicit(object, order) \
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((void)(order), __sync_fetch_and_add(&(object)->__val, 0))
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#define atomic_store_explicit(object, desired, order) \
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((void)atomic_exchange_explicit(object, desired, order))
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#endif
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/*
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* Convenience functions.
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*/
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#define atomic_compare_exchange_strong(object, expected, desired) \
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atomic_compare_exchange_strong_explicit(object, expected, \
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desired, memory_order_seq_cst, memory_order_seq_cst)
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#define atomic_compare_exchange_weak(object, expected, desired) \
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atomic_compare_exchange_weak_explicit(object, expected, \
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desired, memory_order_seq_cst, memory_order_seq_cst)
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#define atomic_exchange(object, desired) \
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atomic_exchange_explicit(object, desired, memory_order_seq_cst)
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#define atomic_fetch_add(object, operand) \
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atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
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#define atomic_fetch_and(object, operand) \
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atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
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#define atomic_fetch_or(object, operand) \
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atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
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#define atomic_fetch_sub(object, operand) \
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atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
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#define atomic_fetch_xor(object, operand) \
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atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
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#define atomic_load(object) \
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atomic_load_explicit(object, memory_order_seq_cst)
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#define atomic_store(object, desired) \
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atomic_store_explicit(object, desired, memory_order_seq_cst)
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/*
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* 7.17.8 Atomic flag type and operations.
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*/
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typedef atomic_bool atomic_flag;
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#define ATOMIC_FLAG_INIT ATOMIC_VAR_INIT(0)
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#define atomic_flag_clear_explicit(object, order) \
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atomic_store_explicit(object, 0, order)
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#define atomic_flag_test_and_set_explicit(object, order) \
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atomic_compare_exchange_strong_explicit(object, 0, 1, order, order)
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#define atomic_flag_clear(object) \
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atomic_flag_clear_explicit(object, memory_order_seq_cst)
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#define atomic_flag_test_and_set(object) \
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atomic_flag_test_and_set_explicit(object, memory_order_seq_cst)
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#endif /* !_STDATOMIC_H_ */
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