NULL pointer

[Henry Spencer]

> But..... for a machine with non-zero null pointer representations
> >		lo_func( ..., (int *)NULL, ... );
> still doesn't work. What the callee routine gets is a pointer with an all-zero
> representation.... which isn't a null pointer. The ONLY thing that does work is
> 		lo_func( ..., p=0, ....);
> where p is a pointer of the requisite type!...

Where on Earth did you get that idea?  (Actually, I know:  from an obsolete
writeup and/or compiler.)  The semantics of casts were somewhat obscure when
they were first introduced, but the eventual rigorous definition was "a cast
acts just like an assignment to a variable of that type".
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry