std::atomic_ref::fetch_add(3)

NAME
std::atomic_ref::fetch_add - std::atomic_ref::fetch_add

Synopsis
   member only of atomic_ref<Integral> and atomic_ref<Floating> template
   specializations
   T fetch_add( T arg, (1)
   std::memory_order order = std::memory_order_seq_cst ) const noexcept;
   member only of atomic_ref<T*> template specialization
   T* fetch_add( std::ptrdiff_t arg, (2)
   std::memory_order order = std::memory_order_seq_cst ) const noexcept;
   Atomically replaces the current value of the referenced object with the result of
   arithmetic addition of the value and arg. This operation is a read-modify-write
   operation. Memory is affected according to the value of order.
   For signed integral types, arithmetic is defined to use two’s complement
   representation. There are no undefined results.
   For floating-point types, the floating-point environment in effect may be different
   from the calling thread's floating-point environment. The operation need not be
   conform to the corresponding std::numeric_limits traits but is encouraged to do so.
   If the result is not a representable value for its type, the result is unspecified
   but the operation otherwise has no undefined behavior.
   For T* types, the result may be an undefined address, but the operation otherwise
   has no undefined behavior. The program is ill-formed if T is not an object type.

Parameters
   arg - the other argument of arithmetic addition
   order - memory order constraints to enforce

Return value
   The value of the referenced object, immediately preceding the effects of this
   function.

Example
    This section is incomplete
    Reason: no example