Forcing packing of a struct isn't possible in standard C, only through compiler extensions. Presumably that's the reason: you have the strange situation where i

Forcing packing of a struct isn't possible in standard C, only through compiler extensions. Presumably that's the reason: you have the strange situation where it's legal (and well-defined) to read the member, or to write it, but to take its address and perform a read through that pointer, causes undefined behaviour. I believe that situation is impossible in standard C.