std::atomic_flag_clear, std::atomic_flag_clear_explicit
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atomic_flag_clearatomic_flag_clear_explicit
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Defined in header
<atomic>
void atomic_flag_clear( volatile std::atomic_flag * obj ) noexcept;
(1)
(since C++11)
void atomic_flag_clear( std::atomic_flag * obj ) noexcept;
(2)
(since C++11)
void atomic_flag_clear_explicit( volatile std::atomic_flag * obj,
std::memory_order order ) noexcept;
(3)
(since C++11)
std::memory_order order ) noexcept;
void atomic_flag_clear_explicit( std::atomic_flag * obj,
std::memory_order order ) noexcept;
(4)
(since C++11)
std::memory_order order ) noexcept;
Atomically changes the state of the std::atomic_flag pointed to by obj to clear (false).
1,2) The memory synchronization ordering is std::memory_order_seq_cst .
3,4) The memory synchronization ordering is order.
If order is one of std::memory_order_consume , std::memory_order_acquire and std::memory_order_acq_rel , the behavior is undefined.
Contents
[edit] Parameters
obj
-
pointer to std::atomic_flag to access
order
-
the memory synchronization ordering
[edit] Notes
std::atomic_flag_clear and std::atomic_flag_clear_explicit can be implemented as obj->clear() and obj->clear(order) respectively.
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2138 | C++11 | order could be std::memory_order_consume | the behavior is undefined in this case |
[edit] See also
C documentation for atomic_flag_clear, atomic_flag_clear_explicit