How to enforce copy elision, why it won't work with deleted copy constructor?

Question

I have an uncopiable class. Copying this would be problematic. I want to guarantee that it won\'t be ever copied, so I made its copy constructor deleted

Answer 1

You can't force copy elision (yet) (see other answers).

However, you can provide a default move constructor for your class, this will move (and thus, not copy) the return value if RVO/NRVO is not possible. To do this you should add = default for your move constructors:

class A {
  public:
    A() = default;
    A(const A&) = delete;
    A(A&&) = default;
    A& operator=(A&&) = default;
};

Example