From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,cef1e23795181e0c
X-Google-Attributes: gid103376,public
From: Matthew Heaney <matthew_heaney@acm.org>
Subject: Re: Alternate to Unchecked_Conversion - Portable?
Date: 1999/02/21
Message-ID: <m3d833e5vr.fsf@mheaney.ni.net>#1/1
X-Deja-AN: 446852901
Sender: matt@mheaney.ni.net
References: <36d05e39.0@news.pacifier.com>
NNTP-Posting-Date: Sun, 21 Feb 1999 14:39:03 PDT
Newsgroups: comp.lang.ada
Date: 1999-02-21T00:00:00+00:00
List-Id: <comp.lang.ada>

"Steve Doiel" <nospam_steved@pacifier.com> writes:

> I discovered a technique for performing a similar function to
> Unchecked_Conversion.  Locating two data structures at the same address by
> defining the first normally and then using an address clause to locate the
> second at the same address as the first (as shown in the following sample):

<example snipped>

> My question is: is this portable?
> 
> I expect that record layouts will be dependent on different endian machines,
> and I know that this technique is inherently unsafe, but it makes things
> very simple.

Don't use address overlays unless you have a compelling reason to do
so.  Use Unchecked_Conversion, which is also "very simple."