stdatomic.h

/*===---- stdatomic.h - Standard header for atomic types and operations -----===
 *
 * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 * See https://llvm.org/LICENSE.txt for license information.
 * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 *
 *===-----------------------------------------------------------------------===
 */

#ifndef __CLANG_STDATOMIC_H
#define __CLANG_STDATOMIC_H

/* If we're hosted, fall back to the system's stdatomic.h. FreeBSD, for
 * example, already has a Clang-compatible stdatomic.h header.
 *
 * Exclude the MSVC path as well as the MSVC header as of the 14.31.30818
 * explicitly disallows `stdatomic.h` in the C mode via an `#error`.  Fallback
 * to the clang resource header until that is fully supported.  The
 * `stdatomic.h` header requires C++23 or newer.
 */
#if __STDC_HOSTED__ &&                                                         \
    __has_include_next(<stdatomic.h>) &&                                       \
    (!defined(_MSC_VER) || (defined(__cplusplus) && __cplusplus >= 202002L))
# include_next <stdatomic.h>
#else

#include <stddef.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/* 7.17.1 Introduction */

#define ATOMIC_BOOL_LOCK_FREE       __CLANG_ATOMIC_BOOL_LOCK_FREE
#define ATOMIC_CHAR_LOCK_FREE       __CLANG_ATOMIC_CHAR_LOCK_FREE
#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L
#define ATOMIC_CHAR8_T_LOCK_FREE    __CLANG_ATOMIC_CHAR8_T_LOCK_FREE
#endif
#define ATOMIC_CHAR16_T_LOCK_FREE   __CLANG_ATOMIC_CHAR16_T_LOCK_FREE
#define ATOMIC_CHAR32_T_LOCK_FREE   __CLANG_ATOMIC_CHAR32_T_LOCK_FREE
#define ATOMIC_WCHAR_T_LOCK_FREE    __CLANG_ATOMIC_WCHAR_T_LOCK_FREE
#define ATOMIC_SHORT_LOCK_FREE      __CLANG_ATOMIC_SHORT_LOCK_FREE
#define ATOMIC_INT_LOCK_FREE        __CLANG_ATOMIC_INT_LOCK_FREE
#define ATOMIC_LONG_LOCK_FREE       __CLANG_ATOMIC_LONG_LOCK_FREE
#define ATOMIC_LLONG_LOCK_FREE      __CLANG_ATOMIC_LLONG_LOCK_FREE
#define ATOMIC_POINTER_LOCK_FREE    __CLANG_ATOMIC_POINTER_LOCK_FREE

/* 7.17.2 Initialization */
#if (defined(__STDC_VERSION__) && __STDC_VERSION__ < 202311L) ||               \
    defined(__cplusplus)
/* ATOMIC_VAR_INIT was removed in C23, but still remains in C++23. */
#define ATOMIC_VAR_INIT(value) (value)
#endif

#if ((defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201710L &&              \
      __STDC_VERSION__ < 202311L) ||                                           \
     (defined(__cplusplus) && __cplusplus >= 202002L)) &&                      \
    !defined(_CLANG_DISABLE_CRT_DEPRECATION_WARNINGS)
/* ATOMIC_VAR_INIT was deprecated in C17 and C++20. */
#pragma clang deprecated(ATOMIC_VAR_INIT)
#endif
#define atomic_init __c11_atomic_init

/* 7.17.3 Order and consistency */

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;

#define kill_dependency(y) (y)

/* 7.17.4 Fences */

/* These should be provided by the libc implementation. */
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)

/* 7.17.5 Lock-free property */

#define atomic_is_lock_free(obj) __c11_atomic_is_lock_free(sizeof(*(obj)))

/* 7.17.6 Atomic integer types */

#ifdef __cplusplus
typedef _Atomic(bool)               atomic_bool;
#else
typedef _Atomic(_Bool)              atomic_bool;
#endif
typedef _Atomic(char)               atomic_char;
typedef _Atomic(signed char)        atomic_schar;
typedef _Atomic(unsigned char)      atomic_uchar;
typedef _Atomic(short)              atomic_short;
typedef _Atomic(unsigned short)     atomic_ushort;
typedef _Atomic(int)                atomic_int;
typedef _Atomic(unsigned int)       atomic_uint;
typedef _Atomic(long)               atomic_long;
typedef _Atomic(unsigned long)      atomic_ulong;
typedef _Atomic(long long)          atomic_llong;
typedef _Atomic(unsigned long long) atomic_ullong;
#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L
typedef _Atomic(unsigned char)      atomic_char8_t;
#endif
typedef _Atomic(uint_least16_t)     atomic_char16_t;
typedef _Atomic(uint_least32_t)     atomic_char32_t;
typedef _Atomic(wchar_t)            atomic_wchar_t;
typedef _Atomic(int_least8_t)       atomic_int_least8_t;
typedef _Atomic(uint_least8_t)      atomic_uint_least8_t;
typedef _Atomic(int_least16_t)      atomic_int_least16_t;
typedef _Atomic(uint_least16_t)     atomic_uint_least16_t;
typedef _Atomic(int_least32_t)      atomic_int_least32_t;
typedef _Atomic(uint_least32_t)     atomic_uint_least32_t;
typedef _Atomic(int_least64_t)      atomic_int_least64_t;
typedef _Atomic(uint_least64_t)     atomic_uint_least64_t;
typedef _Atomic(int_fast8_t)        atomic_int_fast8_t;
typedef _Atomic(uint_fast8_t)       atomic_uint_fast8_t;
typedef _Atomic(int_fast16_t)       atomic_int_fast16_t;
typedef _Atomic(uint_fast16_t)      atomic_uint_fast16_t;
typedef _Atomic(int_fast32_t)       atomic_int_fast32_t;
typedef _Atomic(uint_fast32_t)      atomic_uint_fast32_t;
typedef _Atomic(int_fast64_t)       atomic_int_fast64_t;
typedef _Atomic(uint_fast64_t)      atomic_uint_fast64_t;
typedef _Atomic(intptr_t)           atomic_intptr_t;
typedef _Atomic(uintptr_t)          atomic_uintptr_t;
typedef _Atomic(size_t)             atomic_size_t;
typedef _Atomic(ptrdiff_t)          atomic_ptrdiff_t;
typedef _Atomic(intmax_t)           atomic_intmax_t;
typedef _Atomic(uintmax_t)          atomic_uintmax_t;

/* 7.17.7 Operations on atomic types */

#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

/* 7.17.8 Atomic flag type and operations */

typedef struct atomic_flag { atomic_bool _Value; } atomic_flag;

#ifdef __cplusplus
#define ATOMIC_FLAG_INIT {false}
#else
#define ATOMIC_FLAG_INIT { 0 }
#endif

/* These should be provided by the libc implementation. */
#ifdef __cplusplus
bool atomic_flag_test_and_set(volatile atomic_flag *);
bool atomic_flag_test_and_set_explicit(volatile atomic_flag *, memory_order);
#else
_Bool atomic_flag_test_and_set(volatile atomic_flag *);
_Bool atomic_flag_test_and_set_explicit(volatile atomic_flag *, memory_order);
#endif
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)

#ifdef __cplusplus
}
#endif

#endif /* __STDC_HOSTED__ */
#endif /* __CLANG_STDATOMIC_H */