Standard library header <stdatomic.h> (C++23)

This header was originally in the C standard library (<stdatomic.h>).

This header is part of the concurrency support library.

It is unspecified whether <stdatomic.h> provides any declarations in namespace std.

Contents 1 Macros 2 Types 3 Functions 4 Synopsis Macros
_Atomic (C++23)	compatibility macro such that `_Atomic(T)` is identical to `std::atomic<T>` (function macro) [edit]
ATOMIC_FLAG_INIT (C++11)	initializes an std::atomic_flag to `false` (macro constant) [edit]
Types
atomic_flag (C++11)	the lock-free boolean atomic type (class) [edit]
memory_order (C++11)	defines memory ordering constraints for the given atomic operation (enum) [edit]
atomic_bool (C++11)	`std::atomic<bool>` (typedef) [edit]
atomic_char (C++11)	`std::atomic<char>` (typedef) [edit]
atomic_schar (C++11)	`std::atomic<signed char>` (typedef) [edit]
atomic_uchar (C++11)	`std::atomic<unsigned char>` (typedef) [edit]
atomic_short (C++11)	`std::atomic<short>` (typedef) [edit]
atomic_ushort (C++11)	`std::atomic<unsigned short>` (typedef) [edit]
atomic_int (C++11)	`std::atomic<int>` (typedef) [edit]
atomic_uint (C++11)	`std::atomic<unsigned int>` (typedef) [edit]
atomic_long (C++11)	`std::atomic<long>` (typedef) [edit]
atomic_ulong (C++11)	`std::atomic<unsigned long>` (typedef) [edit]
atomic_llong (C++11)	`std::atomic<long long>` (typedef) [edit]
atomic_ullong (C++11)	`std::atomic<unsigned long long>` (typedef) [edit]
atomic_char8_t (C++20)	`std::atomic<char8_t>` (typedef) [edit]
atomic_char16_t (C++11)	`std::atomic<char16_t>` (typedef) [edit]
atomic_char32_t (C++11)	`std::atomic<char32_t>` (typedef) [edit]
atomic_wchar_t (C++11)	`std::atomic<wchar_t>` (typedef) [edit]
atomic_int8_t (C++11)(optional)	`std::atomic<std::int8_t>` (typedef) [edit]
atomic_uint8_t (C++11)(optional)	`std::atomic<std::uint8_t>` (typedef) [edit]
atomic_int16_t (C++11)(optional)	`std::atomic<std::int16_t>` (typedef) [edit]
atomic_uint16_t (C++11)(optional)	`std::atomic<std::uint16_t>` (typedef) [edit]
atomic_int32_t (C++11)(optional)	`std::atomic<std::int32_t>` (typedef) [edit]
atomic_uint32_t (C++11)(optional)	`std::atomic<std::uint32_t>` (typedef) [edit]
atomic_int64_t (C++11)(optional)	`std::atomic<std::int64_t>` (typedef) [edit]
atomic_uint64_t (C++11)(optional)	`std::atomic<std::uint64_t>` (typedef) [edit]
atomic_int_least8_t (C++11)	`std::atomic<std::int_least8_t>` (typedef) [edit]
atomic_uint_least8_t (C++11)	`std::atomic<std::uint_least8_t>` (typedef) [edit]
atomic_int_least16_t (C++11)	`std::atomic<std::int_least16_t>` (typedef) [edit]
atomic_uint_least16_t (C++11)	`std::atomic<std::uint_least16_t>` (typedef) [edit]
atomic_int_least32_t (C++11)	`std::atomic<std::int_least32_t>` (typedef) [edit]
atomic_uint_least32_t (C++11)	`std::atomic<std::uint_least32_t>` (typedef) [edit]
atomic_int_least64_t (C++11)	`std::atomic<std::int_least64_t>` (typedef) [edit]
atomic_uint_least64_t (C++11)	`std::atomic<std::uint_least64_t>` (typedef) [edit]
atomic_int_fast8_t (C++11)	`std::atomic<std::int_fast8_t>` (typedef) [edit]
atomic_uint_fast8_t (C++11)	`std::atomic<std::uint_fast8_t>` (typedef) [edit]
atomic_int_fast16_t (C++11)	`std::atomic<std::int_fast16_t>` (typedef) [edit]
atomic_uint_fast16_t (C++11)	`std::atomic<std::uint_fast16_t>` (typedef) [edit]
atomic_int_fast32_t (C++11)	`std::atomic<std::int_fast32_t>` (typedef) [edit]
atomic_uint_fast32_t (C++11)	`std::atomic<std::uint_fast32_t>` (typedef) [edit]
atomic_int_fast64_t (C++11)	`std::atomic<std::int_fast64_t>` (typedef) [edit]
atomic_uint_fast64_t (C++11)	`std::atomic<std::uint_fast64_t>` (typedef) [edit]
atomic_intptr_t (C++11)(optional)	`std::atomic<std::intptr_t>` (typedef) [edit]
atomic_uintptr_t (C++11)(optional)	`std::atomic<std::uintptr_t>` (typedef) [edit]
atomic_size_t (C++11)	`std::atomic<std::size_t>` (typedef) [edit]
atomic_ptrdiff_t (C++11)	`std::atomic<std::ptrdiff_t>` (typedef) [edit]
atomic_intmax_t (C++11)	`std::atomic<std::intmax_t>` (typedef) [edit]
atomic_uintmax_t (C++11)	`std::atomic<std::uintmax_t>` (typedef) [edit]
Functions
atomic_is_lock_free (C++11)	checks if the atomic type's operations are lock-free (function template) [edit]
atomic_storeatomic_store_explicit (C++11)(C++11)	atomically replaces the value of the atomic object with a non-atomic argument (function template) [edit]
atomic_loadatomic_load_explicit (C++11)(C++11)	atomically obtains the value stored in an atomic object (function template) [edit]
atomic_exchangeatomic_exchange_explicit (C++11)(C++11)	atomically replaces the value of the atomic object with non-atomic argument and returns the old value of the atomic (function template) [edit]
atomic_compare_exchange_weakatomic_compare_exchange_weak_explicitatomic_compare_exchange_strongatomic_compare_exchange_strong_explicit (C++11)(C++11)(C++11)(C++11)	atomically compares the value of the atomic object with non-atomic argument and performs atomic exchange if equal or atomic load if not (function template) [edit]
atomic_fetch_addatomic_fetch_add_explicit (C++11)(C++11)	adds a non-atomic value to an atomic object and obtains the previous value of the atomic (function template) [edit]
atomic_fetch_subatomic_fetch_sub_explicit (C++11)(C++11)	subtracts a non-atomic value from an atomic object and obtains the previous value of the atomic (function template) [edit]
atomic_fetch_andatomic_fetch_and_explicit (C++11)(C++11)	replaces the atomic object with the result of bitwise AND with a non-atomic argument and obtains the previous value of the atomic (function template) [edit]
atomic_fetch_oratomic_fetch_or_explicit (C++11)(C++11)	replaces the atomic object with the result of bitwise OR with a non-atomic argument and obtains the previous value of the atomic (function template) [edit]
atomic_fetch_xoratomic_fetch_xor_explicit (C++11)(C++11)	replaces the atomic object with the result of bitwise XOR with a non-atomic argument and obtains the previous value of the atomic (function template) [edit]
atomic_flag_test_and_setatomic_flag_test_and_set_explicit (C++11)(C++11)	atomically sets the flag to `true` and returns its previous value (function) [edit]
atomic_flag_clearatomic_flag_clear_explicit (C++11)(C++11)	atomically sets the value of the flag to `false` (function) [edit]
atomic_thread_fence (C++11)	generic memory order-dependent fence synchronization primitive (function) [edit]
atomic_signal_fence (C++11)	fence between a thread and a signal handler executed in the same thread (function) [edit]

Synopsis

template<class T> using /*std-atomic*/ = std::atomic<T>; // exposition-only

#define _Atomic(T) /*std-atomic*/<T>

#define ATOMIC_BOOL_LOCK_FREE                            /* see description */
#define ATOMIC_CHAR_LOCK_FREE                            /* see description */
#define ATOMIC_CHAR8_T_LOCK_FREE                         /* see description */
#define ATOMIC_CHAR16_T_LOCK_FREE                        /* see description */
#define ATOMIC_CHAR32_T_LOCK_FREE                        /* see description */
#define ATOMIC_WCHAR_T_LOCK_FREE                         /* see description */
#define ATOMIC_SHORT_LOCK_FREE                           /* see description */
#define ATOMIC_INT_LOCK_FREE                             /* see description */
#define ATOMIC_LONG_LOCK_FREE                            /* see description */
#define ATOMIC_LLONG_LOCK_FREE                           /* see description */
#define ATOMIC_POINTER_LOCK_FREE                         /* see description */

using std::memory_order;                                 // see description
using std::memory_order_relaxed;                         // see description
using std::memory_order_consume;                         // see description
using std::memory_order_acquire;                         // see description
using std::memory_order_release;                         // see description
using std::memory_order_acq_rel;                         // see description
using std::memory_order_seq_cst;                         // see description

using std::atomic_flag;                                  // see description

using std::atomic_bool;                                  // see description
using std::atomic_char;                                  // see description
using std::atomic_schar;                                 // see description
using std::atomic_uchar;                                 // see description
using std::atomic_short;                                 // see description
using std::atomic_ushort;                                // see description
using std::atomic_int;                                   // see description
using std::atomic_uint;                                  // see description
using std::atomic_long;                                  // see description
using std::atomic_ulong;                                 // see description
using std::atomic_llong;                                 // see description
using std::atomic_ullong;                                // see description
using std::atomic_char8_t;                               // see description
using std::atomic_char16_t;                              // see description
using std::atomic_char32_t;                              // see description
using std::atomic_wchar_t;                               // see description
using std::atomic_int8_t;                                // see description
using std::atomic_uint8_t;                               // see description
using std::atomic_int16_t;                               // see description
using std::atomic_uint16_t;                              // see description
using std::atomic_int32_t;                               // see description
using std::atomic_uint32_t;                              // see description
using std::atomic_int64_t;                               // see description
using std::atomic_uint64_t;                              // see description
using std::atomic_int_least8_t;                          // see description
using std::atomic_uint_least8_t;                         // see description
using std::atomic_int_least16_t;                         // see description
using std::atomic_uint_least16_t;                        // see description
using std::atomic_int_least32_t;                         // see description
using std::atomic_uint_least32_t;                        // see description
using std::atomic_int_least64_t;                         // see description
using std::atomic_uint_least64_t;                        // see description
using std::atomic_int_fast8_t;                           // see description
using std::atomic_uint_fast8_t;                          // see description
using std::atomic_int_fast16_t;                          // see description
using std::atomic_uint_fast16_t;                         // see description
using std::atomic_int_fast32_t;                          // see description
using std::atomic_uint_fast32_t;                         // see description
using std::atomic_int_fast64_t;                          // see description
using std::atomic_uint_fast64_t;                         // see description
using std::atomic_intptr_t;                              // see description
using std::atomic_uintptr_t;                             // see description
using std::atomic_size_t;                                // see description
using std::atomic_ptrdiff_t;                             // see description
using std::atomic_intmax_t;                              // see description
using std::atomic_uintmax_t;                             // see description

using std::atomic_is_lock_free;                          // see description
using std::atomic_load;                                  // see description
using std::atomic_load_explicit;                         // see description
using std::atomic_store;                                 // see description
using std::atomic_store_explicit;                        // see description
using std::atomic_exchange;                              // see description
using std::atomic_exchange_explicit;                     // see description
using std::atomic_compare_exchange_strong;               // see description
using std::atomic_compare_exchange_strong_explicit;      // see description
using std::atomic_compare_exchange_weak;                 // see description
using std::atomic_compare_exchange_weak_explicit;        // see description
using std::atomic_fetch_add;                             // see description
using std::atomic_fetch_add_explicit;                    // see description
using std::atomic_fetch_sub;                             // see description
using std::atomic_fetch_sub_explicit;                    // see description
using std::atomic_fetch_and;                             // see description
using std::atomic_fetch_and_explicit;                    // see description
using std::atomic_fetch_or;                              // see description
using std::atomic_fetch_or_explicit;                     // see description
using std::atomic_fetch_xor;                             // see description
using std::atomic_fetch_xor_explicit;                    // see description
using std::atomic_flag_test_and_set;                     // see description
using std::atomic_flag_test_and_set_explicit;            // see description
using std::atomic_flag_clear;                            // see description
using std::atomic_flag_clear_explicit;                   // see description
#define ATOMIC_FLAG_INIT                                 /* see description */

using std::atomic_thread_fence;                          // see description
using std::atomic_signal_fence;                          // see description;

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Standard library header <stdatomic.h> (C++23)

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