Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site harvard.ARPA
Path: utzoo!linus!philabs!cmcl2!seismo!harvard!stew
From: stew@harvard.ARPA (Stew Rubenstein)
Newsgroups: net.lang.c
Subject: Re: How does one construct a mask for the MS bit?
Message-ID: <455@harvard.ARPA>
Date: Sun, 10-Mar-85 07:35:10 EST
Article-I.D.: harvard.455
Posted: Sun Mar 10 07:35:10 1985
Date-Received: Tue, 12-Mar-85 20:30:50 EST
References: <8849@brl-tgr.ARPA> <169@dmsd.UUCP>
Organization: Aiken Computation Laboratory, Harvard
Lines: 19

> seems that this should work:
> 
> #define MSB(a)		(1<<((sizeof a) * 8 - 1))
> 
> for most unix machines.
> -- 
> John Bass
> DMS Design (System Performance and Arch Consultants)
> {dual,fortune,idi,hpda}!dmsd!bass     (408) 996-0557

Is it portable to assume 8 bit bytes?  Answer:  no, but since there is no
bitsizeof operator, sometimes we must.  There are unix machines which do
not use 8 bit bytes (the BBN C-30 and C-70 come to mind, maybe also some
honeywell machines).  There is also the PDP-10 which, to the best of my
knowledge, does not run unix, but does have C.
-- 
-----------------------
Stew Rubenstein     UUCP: ihnp4!harvard!stew
Harvard Chemistry   ARPA: stew@harvard