pointer to incomplete type?

[James Jones]

On computers for which pointers to different types don't have the same format
(the canonical examples, I think, are non-byte-addressable processors),
how can one safely declare a pointer to an incomplete structure, union, or
enumerated type?  (For that last case, the interpretation of "each enumerated
type shall be compatible with an integer type" may make a difference--is that
intended to be

	"for all enumerated types, there exists an integer type such that..."
or	"there exists an integer type such that for all enumerated types,..."?)

	James Jones