On Saturday, 19 April 2014 at 12:26:16 UTC, Andrej Mitrovic via
Digitalmars-d-learn wrote:
On 4/19/14, Lars T. Kyllingstad via Digitalmars-d-learn
<digitalmars-d-learn@puremagic.com> wrote:
Say I have two structs, defined like this:
struct A { /* could contain whatever */ }
struct B { A a; }
My question is, is it now guaranteed that A.sizeof==B.sizeof?
The best thing to do is add a static assert and then you can
relax:
That's what I've done, but it would be nice to know the code
won't break due to some combination of platform and/or compiler
switches I didn't think to test. Anyway, I've played around a
bit, and found that a combination of struct and field alignment
*can* break my assumption:
align(1) struct A
{
char c;
align(1) int i;
}
struct B { A a; }
Now, A.sizeof is 5, while B.sizeof is 8. I'd have to add
align(1) to the declaration of B to fix it.
