C++11 rvalues and move semantics confusion (return statement)

Question

I\'m trying to understand rvalue references and move semantics of C++11.

What is the difference between these examples, and which of them is going to do no vector cop

Answer 1

None of them will copy, but the second will refer to a destroyed vector. Named rvalue references almost never exist in regular code. You write it just how you would have written a copy in C++03.

std::vector return_vector()
{
    std::vector tmp {1,2,3,4,5};
    return tmp;
}

std::vector rval_ref = return_vector();

Except now, the vector is moved. The user of a class doesn't deal with it's rvalue references in the vast majority of cases.