stdatomic.h

#define ATOMIC_VAR_INIT(value) (value)
#define atomic_is_lock_free(obj) __c11_atomic_is_lock_free(sizeof(*(obj)))
typedef _Atomic(int) atomic_int;

#define __ATOMIC_RELAXED 0
#define __ATOMIC_CONSUME 1
#define __ATOMIC_ACQUIRE 2
#define __ATOMIC_RELEASE 3
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_SEQ_CST 5

typedef enum memory_order {
  memory_order_relaxed = __ATOMIC_RELAXED,
  memory_order_consume = __ATOMIC_CONSUME,
  memory_order_acquire = __ATOMIC_ACQUIRE,
  memory_order_release = __ATOMIC_RELEASE,
  memory_order_acq_rel = __ATOMIC_ACQ_REL,
  memory_order_seq_cst = __ATOMIC_SEQ_CST
} memory_order;

void atomic_thread_fence(memory_order);
void atomic_signal_fence(memory_order);

#define atomic_thread_fence(order) __c11_atomic_thread_fence(order)
#define atomic_signal_fence(order) __c11_atomic_signal_fence(order)

#define atomic_store(object, desired) __c11_atomic_store(object, desired, __ATOMIC_SEQ_CST)
#define atomic_store_explicit __c11_atomic_store

#define atomic_load(object) __c11_atomic_load(object, __ATOMIC_SEQ_CST)
#define atomic_load_explicit __c11_atomic_load

#define atomic_exchange(object, desired) __c11_atomic_exchange(object, desired, __ATOMIC_SEQ_CST)
#define atomic_exchange_explicit __c11_atomic_exchange

#define atomic_compare_exchange_strong(object, expected, desired) __c11_atomic_compare_exchange_strong(object, expected, desired, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)
#define atomic_compare_exchange_strong_explicit __c11_atomic_compare_exchange_strong

#define atomic_compare_exchange_weak(object, expected, desired) __c11_atomic_compare_exchange_weak(object, expected, desired, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)
#define atomic_compare_exchange_weak_explicit __c11_atomic_compare_exchange_weak

#define atomic_fetch_add(object, operand) __c11_atomic_fetch_add(object, operand, __ATOMIC_SEQ_CST)
#define atomic_fetch_add_explicit __c11_atomic_fetch_add

#define atomic_fetch_sub(object, operand) __c11_atomic_fetch_sub(object, operand, __ATOMIC_SEQ_CST)
#define atomic_fetch_sub_explicit __c11_atomic_fetch_sub

#define atomic_fetch_or(object, operand) __c11_atomic_fetch_or(object, operand, __ATOMIC_SEQ_CST)
#define atomic_fetch_or_explicit __c11_atomic_fetch_or

#define atomic_fetch_xor(object, operand) __c11_atomic_fetch_xor(object, operand, __ATOMIC_SEQ_CST)
#define atomic_fetch_xor_explicit __c11_atomic_fetch_xor

#define atomic_fetch_and(object, operand) __c11_atomic_fetch_and(object, operand, __ATOMIC_SEQ_CST)
#define atomic_fetch_and_explicit __c11_atomic_fetch_and

typedef struct atomic_flag { _Atomic(_Bool) _Value; } atomic_flag;

_Bool atomic_flag_test_and_set(volatile atomic_flag *);
_Bool atomic_flag_test_and_set_explicit(volatile atomic_flag *, memory_order);

void atomic_flag_clear(volatile atomic_flag *);
void atomic_flag_clear_explicit(volatile atomic_flag *, memory_order);

#define atomic_flag_test_and_set(object) __c11_atomic_exchange(&(object)->_Value, 1, __ATOMIC_SEQ_CST)
#define atomic_flag_test_and_set_explicit(object, order) __c11_atomic_exchange(&(object)->_Value, 1, order)

#define atomic_flag_clear(object) __c11_atomic_store(&(object)->_Value, 0, __ATOMIC_SEQ_CST)
#define atomic_flag_clear_explicit(object, order) __c11_atomic_store(&(object)->_Value, 0, order)