#define void int vs. #define void char

[Chris Torek]

In article <8085 at elsie.UUCP> ado at elsie.UUCP (Arthur David Olson) writes:
>[the Rationale attached to the draft proposed C standard] contains a
>sample keyword redefinition:
>	#define void int
>along with a note that "The redefinitions of void and const could be
>useful in retrofitting more modern C code to an older implementation."
>Since the Standard requires a void * to have the same representation
>as a char *, and since a char * may not have the same representation
>as an int *, this definition seems suboptimal.

>[but ado was told that] while "#define void char" might be better when
>it comes to pointers, there were other cases where "#define void int"
>was better.  Can anyone give a concrete example?

It is certainly true that `#define void int' (or `typedef int void;')
has been used in the past; you even see this in various books on C.
Indeed, this is the root of an objection I have to the `void *' syntax
for generic pointers.  Had the standard included the line

	typedef void *pointer_t;	/* or (char *) */

in <stddef.h>, one could implement pointer_t on old compilers virtually
painlessly.

Of course, `void *' does somewhat carry the notion that the pointer
does not point to anything in particular, or at least not to anything
concrete.  It is also probably not difficult to implement (it was
certainly trivial in the 4.3-tahoe compilers), so this is just a minor
irritant.  On the other hand, too many minor irritants can keep people
from using something at all. . . .
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris at mimsy.umd.edu	Path:	uunet!mimsy!chris