pointers, tests, casts

[Guy Harris]

 >Isn't the latter [(void *)0] generally preferable, given its possible
 >use as a parameter for a function with no prototype in scope?  Further,
 >isn't the former dangerous in this case, given that there is no
 >guarantee for NULL and (int)0 to have the same representation?

There's no guarantee that "(void *)0" and "(type *)0" have the same
representation, either, unless "type" is either "char" or "void", as far
as I know, so "(void *)0" doesn't guarantee success, either.