Newsgroups: comp.lang.c
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Union type conversions
Message-ID: <1988Jul23.220609.22105@utzoo.uucp>
Organization: U of Toronto Zoology
References: <5754@bloom-beacon.MIT.EDU> <1180@mcgill-vision.UUCP> <3717@ece-csc.UUCP> <12628@mimsy.UUCP>
Date: Sat, 23 Jul 88 22:06:09 GMT

In article <12628@mimsy.UUCP> chris@mimsy.UUCP (Chris Torek) writes:
>Write some correct code that produces a wrong answer if a union of a
>set of elements were implemented as a structure containing all the
>elements, and you will have a proof...

Easy, given (3.5.2.1):  "A pointer to a union object, suitably cast,
points to each of its members... and vice versa."  If two members have
the same type, they have to be in the same place.
-- 
Anyone who buys Wisconsin cheese is|  Henry Spencer at U of Toronto Zoology
a traitor to mankind.  --Pournelle |uunet!mnetor!utzoo! henry @zoo.toronto.edu