std::atomic_ref::operator&=,|=,^= - cppreference.com (original) (raw)
| Provided only when T is an integral type other than cv bool | ||
|---|---|---|
| value_type operator&=( value_type arg ) const noexcept; | (1) | (since C++20) |
| value_type operator|=( value_type arg ) const noexcept; | (2) | (since C++20) |
| value_type operator^=( value_type arg ) const noexcept; | (3) | (since C++20) |
Atomically replaces the current value of the referenced object with the result of computation involving the previous value and arg. These operations are read-modify-write operations.
- operator&= performs atomic bitwise AND. Equivalent to return fetch_and(arg) & arg;.
- operator!= performs atomic bitwise OR. Equivalent to return fetch_or(arg) | arg;.
- operator^= performs atomic bitwise XOR. Equivalent to return fetch_xor(arg) ^ arg;.
These overloads participate in overload resolution only if std::is_const_v<T> is false.
[edit] Parameters
| arg | - | the argument for the arithmetic operation |
|---|
[edit] Return value
The resulting value (that is, the result of applying the corresponding binary operator to the value immediately preceding the effects of the corresponding member function).
[edit] Notes
Unlike most compound assignment operators, the compound assignment operators for atomic_ref do not return a reference to their left-hand arguments. They return a copy of the stored value instead.
[edit] Example
[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 | compound assignment operators were meaningless for const T | constrained to accept only non-const T |
[edit] See also
| | atomically performs bitwise AND between the argument and the value of the referenced object and obtains the value held previously (public member function) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | | atomically performs bitwise OR between the argument and the value of the referenced object and obtains the value held previously (public member function) [edit] | | | atomically performs bitwise XOR between the argument and the value of the referenced object and obtains the value held previously (public member function) [edit] | | | atomically increments or decrements the referenced object by one (public member function) [edit] | | | atomically adds to or subtracts from the referenced value (public member function) [edit] |