Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!elroy!cit-vax!andy
From: andy@cit-vax.Caltech.Edu (Andy Fyfe)
Newsgroups: comp.lang.c
Subject: Re: const void *
Message-ID: <6268@cit-vax.Caltech.Edu>
Date: 26 Apr 88 06:05:01 GMT
References: <6214@cit-vax.Caltech.Edu>
Reply-To: andy@csvax.caltech.edu (Andy Fyfe)
Distribution: na
Organization: California Institute of Technology
Lines: 25

In article <6214@cit-vax.Caltech.Edu> andy@cit-vax.UUCP (Andy Fyfe) writes:
>What does (or should?) the ANSI standard say about const void *?

The reason I wondered about this:  Gnu C wants to be follow the rules
according to ANSI.  The current interpretation says that "void *"
is the generic pointer, so it allows
	any *		<-->	void *
	const any *	<-->	void *
and gives warnings for
	const any *	<-->	const void *
	any *		<-->	const void *
("any" here means any type other than "void".)  RMS seems quite willing
to make gcc conform to the rules.

This has so far given me errors under 2 circumstances.  The first occured
when trying to compile Henry Spencer's string functions.  The second occurs
when using function prototypes that use "const void *" (like fwrite, etc.).

As an aside, K&R 2 (section 7.8.5) makes it clear that the pointer returned
by malloc must explicitly be cast to the correct pointer type.  Why is this
required, given that malloc returns a "void *"?
-- 
Andy Fyfe
            andy@csvax.caltech.edu
            wjafyfe@caltech.bitnet
            andy@cit-vax.UUCP	(...!ames!elroy!cit-vax!andy)