Atomic operations library

< c

If the macro constant __STDC_NO_ATOMICS__(C11) is defined by the compiler, the header <stdatomic.h>, the keyword _Atomic, and all of the names listed here are not provided.


[edit] Types

Defined in header <stdatomic.h>
defines memory ordering constraints
(enum) [edit]
lock-free atomic boolean flag

[edit] Macros

Defined in header <stdatomic.h>
indicates that the given atomic type is lock-free
(macro constant) [edit]
initializes a new atomic_flag
(macro constant) [edit]
(C11)(deprecated in C17)(removed in C23)
initializes a new atomic object
(function macro) [edit]
breaks a dependency chain for memory_order_consume
(function macro) [edit]

[edit] Functions

Defined in header <stdatomic.h>
sets an atomic_flag to true and returns the old value
(function) [edit]
sets an atomic_flag to false
(function) [edit]
initializes an existing atomic object
(function) [edit]
indicates whether the atomic object is lock-free
(function) [edit]
stores a value in an atomic object
(function) [edit]
reads a value from an atomic object
(function) [edit]
swaps a value with the value of an atomic object
(function) [edit]
swaps a value with an atomic object if the old value is what is expected, otherwise reads the old value
(function) [edit]
atomic addition
(function) [edit]
atomic subtraction
(function) [edit]
atomic bitwise OR
(function) [edit]
atomic bitwise exclusive OR
(function) [edit]
atomic bitwise AND
(function) [edit]
generic memory order-dependent fence synchronization primitive
(function) [edit]
fence between a thread and a signal handler executed in the same thread
(function) [edit]

[edit] Types

The standard library offers convenience typedefs for the core language atomic types.

Typedef name Full type name
atomic_bool _Atomic _Bool
atomic_char _Atomic char
atomic_schar _Atomic signed char
atomic_uchar _Atomic unsigned char
atomic_short _Atomic short
atomic_ushort _Atomic unsigned short
atomic_int _Atomic int
atomic_uint _Atomic unsigned int
atomic_long _Atomic long
atomic_ulong _Atomic unsigned long
atomic_llong _Atomic long long
atomic_ullong _Atomic unsigned long long
atomic_char8_t (C23) _Atomic char8_t
atomic_char16_t _Atomic char16_t
atomic_char32_t _Atomic char32_t
atomic_wchar_t _Atomic wchar_t
atomic_int_least8_t _Atomic int_least8_t
atomic_uint_least8_t _Atomic uint_least8_t
atomic_int_least16_t _Atomic int_least16_t
atomic_uint_least16_t _Atomic uint_least16_t
atomic_int_least32_t _Atomic int_least32_t
atomic_uint_least32_t _Atomic uint_least32_t
atomic_int_least64_t _Atomic int_least64_t
atomic_uint_least64_t _Atomic uint_least64_t
atomic_int_fast8_t _Atomic int_fast8_t
atomic_uint_fast8_t _Atomic uint_fast8_t
atomic_int_fast16_t _Atomic int_fast16_t
atomic_uint_fast16_t _Atomic uint_fast16_t
atomic_int_fast32_t _Atomic int_fast32_t
atomic_uint_fast32_t _Atomic uint_fast32_t
atomic_int_fast64_t _Atomic int_fast64_t
atomic_uint_fast64_t _Atomic uint_fast64_t
atomic_intptr_t _Atomic intptr_t
atomic_uintptr_t _Atomic uintptr_t
atomic_size_t _Atomic size_t
atomic_ptrdiff_t _Atomic ptrdiff_t
atomic_intmax_t _Atomic intmax_t
atomic_uintmax_t _Atomic uintmax_t

[edit] References

  • C23 standard (ISO/IEC 9899:2023):
  • 7.17 Atomics <stdatomic.h> (p: TBD)
  • 7.31.8 Atomics <stdatomic.h> (p: TBD)
  • C17 standard (ISO/IEC 9899:2018):
  • 7.17 Atomics <stdatomic.h> (p: TBD)
  • 7.31.8 Atomics <stdatomic.h> (p: TBD)
  • C11 standard (ISO/IEC 9899:2011):
  • 7.17 Atomics <stdatomic.h> (p: 273-286)
  • 7.31.8 Atomics <stdatomic.h> (p: 455-456)

[edit] See also

C++ documentation for Atomic operations library