std::atomic<T>::exchange

(since C++11)
T exchange( T desired, std::memory_order order = std::memory_order_seq_cst ) noexcept;
T exchange( T desired, std::memory_order order = std::memory_order_seq_cst ) volatile noexcept;

Atomically replaces the underlying value with desired. The operation is read-modify-write operation. Memory is affected according to the value of order.

Parameters

desired - value to assign
order - memory order constraints to enforce

Return value

The value of the atomic variable before the call.

See also

(C++11)(C++11)
atomically replaces the value of the atomic object with non-atomic argument and returns the old value of the atomic
(function template)

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