std::atomic_ref::exchange (3) Linux Manual Page

std::atomic_ref<T>::exchange – std::atomic_ref<T>::exchange

Synopsis

T exchange(T desired, std::memory_order order = std::memory_order_seq_cst) const noexcept;
(since C++ 20)

Atomically replaces the value of the referenced object with desired. The operation is a 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 referenced object before the call.