> I was mainly worried about us trying to for example copy a bit-packed > substructure like > > struct A { > unsigned use_1_bit : 1; > struct B { > char large[100]; > } b; > } a, b; > > where b.large[0] is at offset 1 bit of a (I believe this is possible > with Ada, right?).
Actually no, it's not possible. Once something is BLKmode, it's at least aligned on a byte boundary. It's only possible for integral modes. -- Eric Botcazou