| (since C++20)
(member only of
Atomically replaces the current value of the referenced object with the result of bitwise OR of the value and
arg. This operation is a read-modify-write operation. Memory is affected according to the value of
|arg||-||the other argument of bitwise OR|
|order||-||memory order constraints to enforce|
 Return value
The value of the referenced object, immediately preceding the effects of this function.