Does a reference have a storage location?

Question

Does a reference have a storage location or is it just an alias for another location? Does this differ by C++ revision or is it consistent with all versions of C++? And if a

Answer 1

Most compilers, for any C++ standard up to C++17 at least, will effectively implement a reference as a pointer, unless optimized out.

In particular, inside an struct, it will take take up the size of a pointer (plus alignment/padding etc.).

Therefore, this will hold in most environments:

struct S {
    char & a;
};

static_assert(sizeof(S) == sizeof(void *));