Structure pointer question

[Robert Firth]

In article <4606 at haddock.ISC.COM> karl at haddock.ima.isc.com (Karl Heuer) writes:

>It's not a pointer to a completely unspecified type.  It's a pointer to a
>struct with unknown contents.  (This matters.  Although pointer-to-char and
>pointer-to-int might have different internal representations, pointer-to-
>-struct-foo and pointer-to-struct-bar cannot%.)

This makes no sense to me.  Surely a pointer to a struct whose only
component is of type X will use the same representation as a pointer
to a plain X.  Hence if *X and *Y differ, so will *struct{X} and
*struct{Y}.