Hi
I know there are issues becuse on 64 bity systems pointer are 8 byte. And I know there is PTRInt / PTRUInt. An integer of the correct size.

But how much casting is needed?

if I have an integer, word, or byte do I need to go via PTRInt? That is if I know the data is only 4 or less bytes.

So what happens if I do
  SomeInt = Pointer(foo);
Will that compile on 64 bit, or do I need
  SomeInt = PTRInt(Pointer(foo));

In both case the data must be truncated, so the question is not will it work (the data is small enough).
the question is will it compile.

Don't do that, do instead:
 SomeInt = PTRInt(foo);

If you cast it (twice) to pointer it will not result in what you expected, and on 64 bit, you will not solve the problem.

Ido