Function template return type deduction

Question

I have some class C with const and non-const getters for some generic type Node:

template 

        

Answer 1

Since C++14 the return type of a function may be deduced by the compiler:

template
decltype(auto) AliasGetNode(CType& cobject) {
    return cobject.getNode();
}

When you call AliasGetNode on the object of type Node, CType is deduced to Node. But if you call AliasGetNode on the object of type const Node, CType is deduced to const Node.

It is important to make return type of AliasGetNode as decltype(auto), otherwise you will miss a reference and constness for the returned type.