Re: C structure padding

        I have been wondering [....] Given


                struct bigger { struct tag a; char b; };


        can b be placed in the padding for a, so that sizeof(struct bigger)
        is the same as sizeof(struct tag)?


No. Consider that `sizeof(struct a)' must give the total size,
including padding, if address math is to work correctly.


`bzero( &some_bigger.a, sizeof (struct a) )' should effect only the field
`a' and its possible aliases. The field `b' is not a possible alias since
it is a different field in the same structure.




There is probably a lot of code which assumes this won't happen,
but I can't find anything in the Standard which prohibits it.


If the standard gave a formal (mathematical) model of how the store was
used we could derive this. It could never just enumerate all the
interesting cases that such a model would speak to. So, I think we're
stuck deriving things from informal arguments.
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