structure element offsets

[Henry Spencer]

> ...In other words a cast such as (type1 *)(type2 *)x
> will not always give a meaningful answer...

True.

> According to K&R all
> that is required is that (type *)(long *)x == x.

False.  Please cite chapter and verse.  I believe what you are thinking
of is (type *)(char *)x == x, which is (by K&R) valid.  Your example falls
down if, for example, "type" is "char" and the format of "long *" is not
precise enough to point to an individual char within a long.

Or perhaps you were thinking of (type *)(long)x == x ?  That would make me
nervous but it is technically valid.

> ... for good or ill,
> C has been defined such that all members-of-structures share the
> same name-space...

Not modern C, which puts each structure's members in a separate name space.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,decvax,pyramid}!utzoo!henry