Path: utzoo!attcan!utgpu!watmath!att!tut.cis.ohio-state.edu!gem.mps.ohio-state.edu!apple!ames!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: Abandon NULL for (0)
Message-ID: <11127@smoke.BRL.MIL>
Date: 21 Sep 89 21:06:56 GMT
References: <6502@ux.cs.man.ac.uk> <14718@bfmny0.UU.NET>
Reply-To: gwyn@brl.arpa (Doug Gwyn)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 16

In article <14718@bfmny0.UU.NET> tneff@bfmny0.UU.NET (Tom Neff) writes:
>However (0) is not explicitly cast to a pointer type, as NULL may be
>presumed to be when appropriate.

No, it may NOT be so presumed.

>For instance if I refer to, but do not declare or define, an external
>routine that accepts a single pointer as its argument, by saying
>myproc((0)), the compiler will Miranda it into a regular int, rather
>that ((void *) 0), which might have a different size and representation.

And also a different representation from the (struct foo *) that was
expected.

Passing NULL to a function (assuming no prototype in scope) without
casting it to the correct pointer type is a BUG.