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From: jsdy@hadron.UUCP (Joseph S. D. Yao)
Newsgroups: net.lang.c
Subject: Re: Context Variables
Message-ID: <116@hadron.UUCP>
Date: Tue, 3-Dec-85 00:56:01 EST
Article-I.D.: hadron.116
Posted: Tue Dec  3 00:56:01 1985
Date-Received: Thu, 5-Dec-85 08:12:03 EST
References: <230@brl-tgr.ARPA>
Reply-To: jsdy@hadron.UUCP (Joseph S. D. Yao)
Organization: Hadron, Inc., Fairfax, VA
Lines: 16
Summary: Not quite.

On most "reasonable" machine architectures, any scalar or pointer
data type should fit into a long.  However, in C, a pointer isn't
defined to fit into a long (or be in any way commensurable with
a scalar data type), so you may have problems on some of the more
different architectures.  Supposedly, sizeof(long) >= sizeof(int)
>= sizeof(short), although I have seen someone argue on this net
that it was legitimate to have an int whose size > sizeof(long).
I never saw anyone bother to refute that; but I think it's not
likely.  When they are implemented, a (void*) will hold any
pointer data type, so a union {long; void *;} should hold any
object.  But, to help preserve your own sanity and follow the
Prime Rule ("say what you mean"), you really should make a union
of all the different data types with which you'll be working.
-- 

	Joe Yao		hadron!jsdy@seismo.{CSS.GOV,ARPA,UUCP}