From: utzoo!decvax!cca!lwa%MIT-CSR@MIT-Multics@sri-unix
Newsgroups: net.unix-wizards
Title: Re: (char *)1
Article-I.D.: sri-unix.3270
Posted: Tue Sep 14 15:18:49 1982
Received: Thu Sep 16 01:07:40 1982

Date: 10 Sep 1982 1913-EDT (Friday)
Actually, (char *)1 or something similar is useful in certain very
restricted circumstances: namely, accessing device control registers,
or other hardware locations, on machines like pdp-11's in which I/O
devices live in the same address space as memory.  I have written
several standalone programs (eg. for hardware diagnostics) in C;
all of them use this kind of cast.  Also, if you'll look at UNIX
device drivers in the more recent systems (Version 7 and up)
you'll find that they do the same thing.
					-Larry Allen
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