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From: chris@umcp-cs.UUCP
Newsgroups: net.unix-wizards
Subject: Re: NULL vs 0
Message-ID: <4808@umcp-cs.UUCP>
Date: Thu, 19-Jan-84 19:29:23 EST
Article-I.D.: umcp-cs.4808
Posted: Thu Jan 19 19:29:23 1984
Date-Received: Sat, 21-Jan-84 01:49:03 EST
References: <345@hocda.UUCP> <2406@rabbit.UUCP>
Organization: Univ. of Maryland, Computer Science Dept.
Lines: 29

I have one little minor thing to say here.  I don't know about those 68k
systems that have sizeof (int) == 2, sizeof (char *) == 4, but all the
stdio.h files I've seen say

	#define NULL 0

(NOT #define NULL ((char *) 0)), so it won't make a bit of difference if
you write

	f () { g (NULL, 1, 2); }

instead of

	f () { g (0, 1, 2); }

What you must do instead is write

	f () { g ((char *) NULL, 1, 2); }	/* or (char *) 0 */

(assuming g expects it's first argument to be of type "char *").

I agree that it's good practise to include type casts for function
parameters; however, as a "midnight hacker" I know how easy it is to
miss these.  (But I *do* use lint!)  (Ever run lint on a 4.1BSD kernel
after installing CMU IPC?)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci
UUCP:	{seismo,allegra,brl-bmd}!umcp-cs!chris
CSNet:	chris@umcp-cs		ARPA:	chris.umcp-cs@CSNet-Relay