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

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< cpp‎ | atomic‎ | atomic

T operator++() noexcept; T operator++() volatile noexcept; | (1) | (member only of `atomic<Integral>` template specialization) (since C++11)
T* operator++() noexcept; T* operator++() volatile noexcept; | (1) | (member only of `atomic<T*>` template specialization) (since C++11)
T operator++( int ) noexcept; T operator++( int ) volatile noexcept; | (2) | (member only of `atomic<Integral>` template specialization) (since C++11)
T* operator++( int ) noexcept; T* operator++( int ) volatile noexcept; | (2) | (member only of `atomic<T*>` template specialization) (since C++11)
T operator--() noexcept; T operator--() volatile noexcept; | (3) | (member only of `atomic<Integral>` template specialization) (since C++11)
T* operator--() noexcept; T* operator--() volatile noexcept; | (3) | (member only of `atomic<T*>` template specialization) (since C++11)
T operator--( int ) noexcept; T operator--( int ) volatile noexcept; | (4) | (member only of `atomic<Integral>` template specialization) (since C++11)
T* operator--( int ) noexcept; T* operator--( int ) volatile noexcept; | (4) | (member only of `atomic<T*>` template specialization) (since C++11)

Atomically increments or decrements the current value. The operation is read-modify-write operation.

1) Performs atomic pre-increment. Equivalent to fetch_add(1)+1.
2) Performs atomic post-increment. Equivalent to fetch_add(1).
3) Performs atomic pre-decrement. Equivalent to fetch_sub(1)-1
4) Performs atomic post-decrement. Equivalent to 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 atomic variable after the modification. Formally, the result of incrementing/decrementing the value immediately preceding the effects of this function in the modification order of `*this`.
2,4) The value of the atomic variable before the modification. Formally, the value immediately preceding the effects of this function in the modification order of `*this`.

### Notes

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

### 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 | arithmetic permitted on pointers to cv void or function | made ill-formed

### See also

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

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