# std::atomic_ref<T>::operator++,++(int),--,--(int)

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< cpp‎ | atomic‎ | atomic ref

member only of `atomic_ref<Integral>` and `atomic_ref<T*>` template specializations |  |
value_type operator++() const noexcept; | (1) | (since C++20)
value_type operator++(int) const noexcept; | (2) | (since C++20)
value_type operator--() const noexcept; | (3) | (since C++20)
value_type operator--(int) const noexcept; | (4) | (since C++20)

Atomically increments or decrements the current value of the referenced object. These operations are read-modify-write operations.

1) Performs atomic pre-increment. Equivalent to return fetch_add(1) + 1;.
2) Performs atomic post-increment. Equivalent to return fetch_add(1);.
3) Performs atomic pre-decrement. Equivalent to return fetch_sub(1) - 1;
4) Performs atomic post-decrement. Equivalent to return fetch_sub(1);.

For signed `Integral` types, arithmetic is defined to use two’s complement representation. There are no undefined results.

For `T*` types, the result may be an undefined address, but the operations otherwise have no undefined behavior. The program is ill-formed if `T` is not an object type.

### Parameters

(none)

### Return value

1,3) The value of the referenced object after the modification.
2,4) The value of the referenced object before the modification.

### Notes

Unlike most pre-increment and pre-decrement operators, the pre-increment and pre-decrement operators for `atomic_ref` do not return a reference to the modified object. They return a copy of the stored value instead.

### See also

fetch_add | atomically adds the argument to the value stored in the referenced object and obtains the value held previously (public member function)
fetch_sub | atomically subtracts the argument from the value stored in the referenced object and obtains the value held previously (public member function)
operator+=operator-=operator&=operator|=operator^= | atomically adds, subtracts, or performs bitwise AND, OR, XOR with the referenced value (public member function)

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