atomic_flag_clear, atomic_flag_clear_explicit

< c‎ | atomic
Defined in header <stdatomic.h>
void atomic_flag_clear( volatile atomic_flag* obj );
(1) (since C11)
void atomic_flag_clear_explicit( volatile atomic_flag* obj, memory_order order );
(2) (since C11)

Atomically changes the state of a atomic_flag pointed to by obj to clear (false). The first version orders memory accesses according to memory_order_seq_cst, the second version orders memory accesses according to order.

The argument is pointer to a volatile atomic flag to accept addresses of both non-volatile and volatile (e.g. memory-mapped I/O) atomic flags.


obj - pointer to the atomic flag object to modify
order - the memory synchronization ordering for this operation: all values are permitted

Return value



  • C11 standard (ISO/IEC 9899:2011):
  • The atomic_flag_clear functions (p: 286)

See also

sets an atomic_flag to true and returns the old value
C++ documentation for atomic_flag_clear, atomic_flag_clear_explicit