Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!sdd.hp.com!uakari.primate.wisc.edu!aplcen!haven!ncifcrf!lhc!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.std.c
Subject: Re: Structure Member Padding
Message-ID: <13345@smoke.BRL.MIL>
Date: 12 Jul 90 21:00:24 GMT
References: <1990Jul7.225141.12002@sq.sq.com> <13321@smoke.BRL.MIL> <17069@haddock.ima.isc.com>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 9

In article <17069@haddock.ima.isc.com> karl@kelp.ima.isc.com (Karl Heuer) writes:
>I don't get it.  Why should a half-word of internal padding be necessary or
>desirable?  Looks to me like the obvious implementation is to make it a
>two-word struct, with the first word containing s and a and b, and the second
>word containing c and three pad bytes.  What's the problem?

On many, perhaps most, word-addressed architectures there are speed advantages
to not trying to pack different small data types within the same word, unless
bit fields are explicitly requested.