Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!rutgers!cmcl2!phri!marob!daveh
From: daveh@marob.masa.com (Dave Hammond)
Newsgroups: comp.lang.c
Subject: Re: Abandon NULL for (0)
Message-ID: <252B5E41.1244@marob.masa.com>
Date: 5 Oct 89 13:59:27 GMT
Reply-To: daveh@marob.masa.com (Dave Hammond)
Organization: ESCC,  New York City
Lines: 26

In article <10839@dasys1.UUCP> jpr@dasys1.UUCP (Jean-Pierre Radley) writes:
>I have found my code to more readable if I use these two defines:
>
>#define	NULLC (char *)0
>#define NULLF (FILE *)0
>

For the vast majority of data types, a single macro can produce
a properly cast null pointer:

#define NIL(t)	(t *)0

This produces fairly readable and maintainable code, as in:

fp = fopen("foo","r");
if (fp == NIL(FILE))
	{ ... }

The only pathological case which I define a separate macro for is
null pointer-to-function:

#define NILFUNC(t)	(t (*)())0

--
Dave Hammond
daveh@marob.masa.com