Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!rutgers!ucla-cs!heather
From: heather@SEAS.UCLA.EDU
Newsgroups: comp.lang.c
Subject: Re: use of NULL
Keywords: NULL zero 0 C Microsoft
Message-ID: <20928@shemp.CS.UCLA.EDU>
Date: 23 Feb 89 17:29:06 GMT
References: <1167@unisec.usi.com. <5312@turnkey.TCC.COM. <9582@smoke.BRL.MIL. <399@twwells.uucp: <973@optilink.UUCP> <9684@smoke.BRL.MIL>
Sender: news@CS.UCLA.EDU
Reply-To: heather@SEAS.UCLA.EDU (Heather Burris)
Organization: UCLA School Of Engineering &  Applied Science
Lines: 20


In article <9684@smoke.BRL.MIL> gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
>In article <973@optilink.UUCP> cramer@optilink.UUCP (Clayton Cramer) writes:
>>Never pass bare 0 as a pointer argument -- but use the stdio.h
>>definition of NULL, and the segmented architecture will NOT screw
>>you.
>
>Wrong.  Use of uncast NULL as an argument to a function is never correct
>usage; although you can get away with it sometimes, it only "works" by
>accident and may quit working suddenly if the implementation changes.
>It is definitely not portable.  Always cast 0 or NULL to the correct
>pointer type when used as a function argument.

Excuse me for a probably naive question that I've had since following the
discussion of passing NULL to functions: Why doesn't the C standard
treat NULL or 0 (a static/constant NULL or 0, i.e. indicated at compile time)
passed to a function that has a pointer value in the function prototype 
as a special case and do the cast implicitly?

Heather Burris, UCLA