std::atomic_ref<T>::exchange
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std::atomic_ref
atomic_ref::exchange
(C++26)
(C++26)
(C++26)
value_type exchange( value_type desired,
(constexpr since C++26)
std::memory_order order =
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.
This overload participates in overload resolution only if std::is_const_v <T> is false.
[edit] Parameters
desired
-
value to assign
order
-
memory order constraints to enforce
[edit] Return value
The value of the referenced object before the call.
[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 3508 (P3323R1) |
C++20 | exchange was meaningless for const T
|
constrained to accept only non-const T
|