How can I reliably get an object's address when operator& is overloaded?

Question

Consider the following program:

struct ghost
{
    // ghosts like to pretend that they don\'t exist
    ghost* operator&() const volatile { return 0; }
}         


        

Answer 1

Use std::addressof.

You can think of it as doing the following behind the scenes:

1. Reinterpret the object as a reference-to-char
2. Take the address of that (won’t call the overload)
3. Cast the pointer back to a pointer of your type.

Existing implementations (including Boost.Addressof) do exactly that, just taking additional care of const and volatile qualification.