Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: how do I initialize a function pointer to be NULL ?
Message-ID: <6440@brl-smoke.ARPA>
Date: Sun, 20-Sep-87 20:28:59 EDT
Article-I.D.: brl-smok.6440
Posted: Sun Sep 20 20:28:59 1987
Date-Received: Mon, 21-Sep-87 00:38:33 EDT
References: <197@tiger.Princeton.EDU> <27742@sun.uucp> <2236@emory.uucp>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 15
Keywords: NULLFUNC NULL

#define	NULL	0	/* universally correct */

Just don't attempt to pass this as a parameter to a function without
supplying the proper cast.
	func( stuff, (int (*)())NULL );	/* for example */

If you make extensive usage of such parameters, then it might save
some typing to define shorthand such as

#define	NULL_DIRENTP	((struct dirent *)0)

This would be particularly useful if the type involved might change
in a future revision of the code.

Ignore all babble about defining NULL as 0L etc.