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std::atomic_ref<T>::notify_one

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< cpp‎ | atomic‎ | atomic ref
 
 
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void notify_one() const noexcept;
(constexpr since C++26)

Performs atomic notifying operations.

If there is a thread blocked in atomic waiting operation (i.e. wait()) on *ptr, then unblocks at least one such thread; otherwise does nothing. This overload participates in overload resolution only if std::is_const_v<T> is false.

Contents

[edit] Notes

This form of change-detection is often more efficient than simple polling or pure spinlocks.

[edit] Example

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 3508
(P3323R1)
C++20 notify_one was meaningless for const T constrained to accept only non-const T

[edit] See also

blocks the thread until notified and the atomic value changes
(public member function) [edit]
blocks the thread until notified and the atomic value changes
(function template) [edit]
notifies a thread blocked in atomic_wait
(function template) [edit]