Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: Help me cast this!
Message-ID: <7845@brl-smoke.ARPA>
Date: 6 May 88 18:20:33 GMT
References: <294@fedeva.UUCP> <7822@brl-smoke.ARPA> <3802@diku.dk>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 14

In article <3802@diku.dk> njk@diku.dk (Niels J|rgen Kruse) writes:
>... I gather that malloc has been redefined as void *malloc().
>Is a (void *) guaranteed to satisfy all alignment requirements?

No.  There are two distinct properties of the pointer returned by
malloc(): one is that it is a "generic" pointer, capable of being
safely converted to a pointer to any object type; the other is that
it is guaranteed to be properly aligned so that this conversion is
meaningful.  These two properties are NOT the same and should not
be bundled into a single language element.  The "super-aligned"
property is only true of pointers returned by malloc() and
therefore didn't seem to need a specific notion in the C language.
The "generic" property is essentially what ANSI C "void *" is
intended for.