# std::atomic_fetch_xor, std::atomic_fetch_xor_explicit

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< cpp‎ | atomic

Defined in header `<atomic>` |  |
template< class T > T atomic_fetch_xor( std::atomic <T>* obj, typename std::atomic <T>::value_type arg ) noexcept; | (1) | (since C++11)
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; | (3) | (since C++11)
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; | (4) | (since C++11)

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:

1,2) obj->fetch_xor(arg)
3,4) obj->fetch_xor(arg, order)

If `std::atomic<T>` has no `fetch_xor` member (this member is only provided for integral types except bool), 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

### Return value

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

### 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 was required because `T` was deduced from multiple arguments | `T` is only deduced from obj

### 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)
C documentation for atomic_fetch_xor, atomic_fetch_xor_explicit

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