header

<atomic>

Atomic

Atomic types are types that encapsulate a value whose access is guaranteed to not cause data races and can be used to synchronize memory accesses among different threads.

This header declares two C++ classes, atomic and atomic_flag, that implement all the features of atomic types in self-contained classes. The header also declares an entire set of C-style types and functions compatible with the atomic support in C.

Classes

atomic: Atomic (class template )

atomic_flag: Atomic flag (class )

Types

memory_order: Memory order (enum )

C-style atomic types

The following atomic types are also defined in this header; each with the same behavior as the respective instantiation of atomic for the listed contained type.

contained type	atomic type	description
`bool`	`atomic_bool`
`char`	`atomic_char`	atomics for fundamental integral types. These are either typedefs of the corresponding full specialization of the `atomic` class template or a base class of such specialization.
`signed char`	`atomic_schar`
`unsigned char`	`atomic_uchar`
`short`	`atomic_short`
`unsigned short`	`atomic_ushort`
`int`	`atomic_int`
`unsigned int`	`atomic_uint`
`long`	`atomic_long`
`unsigned long`	`atomic_ulong`
`long long`	`atomic_llong`
`unsigned long long`	`atomic_ullong`
`wchar_t`	`atomic_wchar_t`
`char16_t`	`atomic_char16_t`
`char32_t`	`atomic_char32_t`
`intmax_t`	`atomic_intmax_t`	atomics for width-based integrals (those defined in `<cinttypes>`). Each of these is either an alias of one of the above atomics for fundamental integral types or of a full specialization of the `atomic` class template with an extended integral type. Where N is one in 8, 16, 32, 64, or any other type width supported by the library.
`uintmax_t`	`atomic_uintmax_t`
`int_least`N`_t`	`atomic_int_least`N`_t`
`uint_least`N`_t`	`atomic_uint_least`N`_t`
`int_fast`N`_t`	`atomic_int_fast`N`_t`
`uint_fast`N`_t`	`atomic_uint_fast`N`_t`
`intptr_t`	`atomic_intptr_t`
`uintptr_t`	`atomic_uintptr_t`
`size_t`	`atomic_size_t`
`ptrdiff_t`	`atomic_ptrdiff_t`

Functions

kill_dependency: Kill dependency (function )

atomic_thread_fence: Thread fence (function )

atomic_signal_fence: Signal fence (function )

Functions for atomic objects (C-style)

atomic_is_lock_free: Is lock-free (function )

atomic_init: Initialize atomic object (function )

atomic_store: Modify contained value (function )

atomic_store_explicit: Modify contained value (explicit memory order) (function )

atomic_load: Read contained value (function )

atomic_load_explicit: Read contained value (explicit memory order) (function )

atomic_exchange: Read and modify contained value (function )

atomic_exchange_explicit: Read and modify contained value (explicit memory order) (function )

atomic_compare_exchange_weak: Compare and exchange contained value (weak) (function )

atomic_compare_exchange_weak_explicit: Compare and exchange contained value (weak, explicit) (function )

atomic_compare_exchange_strong: Compare and exchange contained value (strong) (function )

atomic_compare_exchange_strong_explicit: Compare and exchange contained value (strong, explicit) (function )

atomic_fetch_add: Add to contained value (function )

atomic_fetch_add_explicit: Add to contained value (explicit memory order) (function )

atomic_fetch_sub: Subtract from contained value (function )

atomic_fetch_sub_explicit: Subtract from contained value (explicit memory order) (function )

atomic_fetch_and: Apply bitwise AND to contained value (function )

atomic_fetch_and_explicit: Apply bitwise AND to contained value (explicit memory order) (function )

atomic_fetch_or: Apply bitwise OR to contained value (function )

atomic_fetch_or_explicit: Apply bitwise OR to contained value (explicit memory order) (function )

atomic_fetch_xor: Apply bitwise XOR to contained value (function )

atomic_fetch_xor_explicit: Apply bitwise XOR to contained value (explicit memory order) (function )

Functions for atomic flags (C-style)

atomic_flag_test_and_set: Test and set atomic flag (function )

atomic_flag_test_and_set_explicit: Test and set atomic flag (explicit memory order) (function )

atomic_flag_clear: Clear atomic flag (function )

atomic_flag_clear_explicit: Clear atomic flag (explicit memory order) (function )

Macro functions

ATOMIC_VAR_INIT: Initialization of atomic variable (macro )

ATOMIC_FLAG_INIT: Initialization of atomic flag (macro )

Macro constants

macro	relative to types	defined as
`ATOMIC_BOOL_LOCK_FREE`	`bool`	`0` if the types are never lock-free. `1` it the types are sometimes lock-free. `2` if the types are always lock-free. Consistent with the value returned by `atomic::is_lock_free`.
`ATOMIC_CHAR_LOCK_FREE`	`char` `signed char` `unsigned char`
`ATOMIC_SHORT_LOCK_FREE`	`short` `unsigned short`
`ATOMIC_INT_LOCK_FREE`	`int` `unsigned int`
`ATOMIC_LONG_LOCK_FREE`	`long` `unsigned long`
`ATOMIC_LLONG_LOCK_FREE`	`long long` `unsigned long long`
`ATOMIC_WCHAR_T_LOCK_FREE`	`wchar_t`
`ATOMIC_CHAR16_T_LOCK_FREE`	`char16_t`
`ATOMIC_CHAR32_T_LOCK_FREE`	`char32_t`
`ATOMIC_POINTER_LOCK_FREE`	`U` (for any type `U`)*

<atomic>

Classes

Types

C-style atomic types

Functions

Functions for atomic objects (C-style)

Functions for atomic flags (C-style)

Macro functions

Macro constants

C++

Reference

C library:

Containers:

Input/Output:

Multi-threading:

Other:

<atomic>

classes:

enum types:

functions:

initialization macros:

functions (C-style atomics):