atomic_flag

 

C

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Strings library

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Concurrency support (C11)

Technical Specifications

Symbol index

 

Concurrency support library

Threads thrd_create thrd_equal thrd_current    thrd_sleep thrd_yield thrd_exit thrd_detach thrd_join thrd_successthrd_timedoutthrd_busythrd_nomemthrd_error    Atomic operations atomic_init ATOMIC_VAR_INIT (until C23) ATOMIC_***_LOCK_FREE atomic_is_lock_free atomic_store atomic_load atomic_exchange atomic_compare_exchange atomic_fetch_add atomic_fetch_sub atomic_fetch_or atomic_fetch_xor atomic_fetch_and

Atomic flags atomic_flag ATOMIC_FLAG_INIT atomic_flag_test_and_set atomic_flag_clear Memory ordering memory_order kill_dependency atomic_thread_fence atomic_signal_fence Mutual exclusion mtx_init mtx_lock mtx_timedlock mtx_trylock call_once mtx_unlock mtx_destroy mtx_plainmtx_recursivemtx_timed Condition variables cnd_init cnd_signal cnd_broadcast cnd_wait cnd_timedwait cnd_destroy Thread-local storage thread_local TSS_DTOR_ITERATIONS    tss_create tss_get tss_set tss_delete

 

Defined in header <stdatomic.h>
typedef struct /* unspecified */ atomic_flag;		(since C11)

atomic_flag is an atomic boolean type. Unlike other atomic types, it is guaranteed to be lock-free. Unlike atomic_bool, atomic_flag does not provide load or store operations.

References

• C23 standard (ISO/IEC 9899:2024):

• 7.17.1/5 atomic_flag (p: 293)

• 7.17.8 Atomic flag type and operations (p: 302-303)

• C17 standard (ISO/IEC 9899:2018):

• 7.17.1/4 atomic_flag (p: 200)

• 7.17.8 Atomic flag type and operations (p: 208-209)

• C11 standard (ISO/IEC 9899:2011):

• 7.17.1/4 atomic_flag (p: 273)

• 7.17.8 Atomic flag type and operations (p: 285-286)

See also

ATOMIC_FLAG_INIT (C11)	initializes a new atomic_flag (macro constant)
atomic_flag_test_and_setatomic_flag_test_and_set_explicit (C11)	sets an atomic_flag to true and returns the old value (function)
atomic_flag_clearatomic_flag_clear_explicit (C11)	sets an atomic_flag to false (function)
C++ documentation for atomic_flag