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Path: utzoo!watmath!watnot!watdaisy!dvadura
From: dvadura@watdaisy.UUCP
Newsgroups: comp.lang.c
Subject: Re: Casting NULL?
Message-ID: <8087@watdaisy.UUCP>
Date: Fri, 23-Jan-87 09:27:31 EST
Article-I.D.: watdaisy.8087
Posted: Fri Jan 23 09:27:31 1987
Date-Received: Sat, 24-Jan-87 04:50:07 EST
References: <3179@brl-adm.ARPA>
Reply-To: dvadura@watdaisy.UUCP (Dennis Vadura)
Organization: Computer Science Dept., University of Waterloo
Lines: 22

In article <3179@brl-adm.ARPA> Peter Steele - Acadia writes:
>I have a question about pointers: I just recently read
>a C text where whenever NULL was passed as a parameter
>it was casted to the proper type.
>
>He claimed that
>this is required because pointers to different types of objects
>may not be the same size.

I don't know how common it is, but a simple solution is to define:

#define NIL(a) (a *)NULL;

when you need to pass a null pointer to an int or a char then say

	NIL( int ) or NIL( char )

this works for structs and other objects as well.

     	typedef foo { .... } BAR;

then NIL( BAR ) is a NULL pointer of type BAR.