Should a move constructor take a const or non-const rvalue reference?

Question

In several places I\'ve seen the recommended signatures of copy and move constructors given as:

struct T
{
    T();
    T(const T& other);
    T(T&&a         


        

Answer 1

It should be a non-const rvalue reference.

If an object is placed in read-only memory, you can't steal resources from it, even if its formal lifetime is ending shortly. Objects created as const in C++ are allowed to live in read-only memory (using const_cast to try to change them results in undefined behavior).