# std::atomic_fetch_xor, std::atomic_fetch_xor_explicit

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< cpp‎ | atomic

Defined in header `<atomic>` |  |
| (1) | (since C++11)
template< class T > T atomic_fetch_xor( std::atomic <T>* obj, typename std::atomic <T>::value_type arg ) noexcept; |  |
template< class T > T atomic_fetch_xor( volatile std::atomic <T>* obj, typename std::atomic <T>::value_type arg ) noexcept; |  |
| (2) | (since C++11)
template< class T > T atomic_fetch_xor_explicit( std::atomic <T>* obj, typename std::atomic <T>::value_type arg, std::memory_order order) noexcept; |  |
template< class T > T atomic_fetch_xor_explicit( volatile std::atomic <T>* obj, typename std::atomic <T>::value_type arg, std::memory_order order) noexcept; |  |

Atomically replaces the value pointed by `obj` with the result of bitwise XOR between the old value of `obj` and `arg`. Returns the value `obj` held previously.

The operation is performed as if the following is executed:

1) obj->fetch_xor(arg)
2) obj->fetch_xor(arg, order)

If `std::atomic<T>` has no `fetch_xor` member (this member is only provided for integral types), the program is ill-formed.

### Parameters

obj | - | pointer to the atomic object to modify
arg | - | the value to bitwise XOR to the value stored in the atomic object
order | - | the memory synchronization ordering for this operation: all values are permitted.

### Return value

The value immediately preceding the effects of this function in the modification order of `*obj`.

### Possible implementation

    template< class T >
    T atomic_fetch_xor( std::atomic<T>* obj, typename std::atomic<T>::value_type arg )
    {
        return obj->fetch_xor(arg);
    }

### Example

| This section is incomplete Reason: no example

### Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
P0558R1 | C++11 | exact type match required because `T` is deduced from multiple arguments | `T` is deduced from the `atomic` argument only

### See also

fetch_xor | atomically performs bitwise XOR between the argument and the value of the atomic object and obtains the value held previously (public member function of `std::atomic<T>`)
atomic_fetch_oratomic_fetch_or_explicit (C++11)(C++11) | replaces the atomic object with the result of bitwise OR with a non-atomic argument and obtains the previous value of the atomic (function template)
atomic_fetch_andatomic_fetch_and_explicit (C++11)(C++11) | replaces the atomic object with the result of bitwise AND with a non-atomic argument and obtains the previous value of the atomic (function template)

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