Question

As title says, I’m currently doing some small hacks with pointers in C++, but something isn’t working out here’s what I got:

uintptr_t texture_pointer = (int)((void*) &texture);

Where texture is a class; this seems to work fine, as I’m getting a pointer value out, and I have insured that I’m getting the same value into my other function, which is supposed to get the object back; this is the code that fails:

std::cout << "C++ BEFORE: " << texture_pointer << std::endl;
Texture texture = *(Texture*)((void*) texture_pointer);
std::cout << "C++ AFTER: " << (uintptr_t)((void*) &texture) << std::endl;

The output I was excepting; was that the same number for both, however I’m getting two different numbers, hence why I think there must be an error, but I can’t seem to find it.

Example output:

C++ BEFORE: 2685236
C++ AFTER: 2684960

Answer 1

This line:

Texture texture = *(Texture*)((void*) texture_pointer);

creates a new Texture object as a copy of the original one. Obviously, this has a different address to the old one.

You could do this:

Texture &texture = *(Texture*)((void*) texture_pointer);

(i.e. create a reference to the old one).

But in general, messing about with pointers like this is more trouble than it’s worth.