union

[MrViggy]

I didn't say that the example I posted was that case, I was just saying that it's a more advanced case, that might be undefined.

What would happen here?

union foo {
   bool b;
   short s;
   int i;
};

Is it defined where the bits for each are stored, or is that up to the compiler?

I believe that's compile dependent. I think...

Viggy

[S_M_A]

As I read this http://www.open-std.org/jtc1/sc22/wg...2011/n3242.pdf (page 226, §5) each member in a union should have the same address so the mapping is defined. Endian has to be considered though.

[MrViggy]

That's right, each member in the union starts at the same address.

Viggy