On 29 March 2015 at 20:28, Mason wrote: > It seems to me that there is another possible layout for bar2: > > s(80) + int(4) + pad(44) = 128 bytes > > The problem then would be that struct foo2 pointers might either > point to a "stand-alone" foo2 -- s(80) + pad(48) -- or to a bar2 > "inner struct" (one with the int before the padding). And that's what kills your idea. Given a pointer to foo2 I should be able to do a memcpy(p, sizeof(struct foo2), q) and not worry about overwriting some other value that is not part of the foo2 object. > If gcc generates code that leaves the padding untouched, then > the same code works with both variants, and my suggestion would > be valid. Or did I get something wrong? As Andreas already said, structure members cannot overlap.
