Path: utzoo!attcan!uunet!ginosko!uakari.primate.wisc.edu!pikes!boulder!sunybcs!sbcs!bnlux0!adelphi!promark!mark
From: mark@promark.UUCP (Mark J. DeFilippis)
Newsgroups: comp.unix.questions
Subject: Re: Are terminal writes atomic?
Summary: I should have qualifed this...
Message-ID: <191@promark.UUCP>
Date: 7 Oct 89 19:17:44 GMT
References: <-286379999@hpcupt1.HP.COM> <1118@cs.yale.edu> <186@promark.UUCP> <19972@mimsy.UUCP>
Organization: Promark Data Concepts, Garden City, NY
Lines: 22

In article <19972@mimsy.UUCP>, chris@mimsy.UUCP (Chris Torek) writes:
> In article <186@promark.UUCP> mark@promark.UUCP (Mark J. DeFilippis) writes:
> >How about we take this further.  The answer to this question is an
> >undocumented feature of write() under Unix.  Several Authors note this
> 
> Of course, it might be undocumented because it is false.
> 
> On Berkeley systems (4BSD, at least), writes to character devices are

Indeed I should have qualified my statement, however almost everyone is
familiar with Rochkind's _Advanced Unix Programming_ book, and they are
aware it is a SYSTEM V book, not a 4BSD Unix book.
Under System V, it is a known undocumented item.  By undocumented, I mean
it was left out of the documentation and under ALL true Unix System V systems,
atomic writes at the system call level are guaranteed. Yes, 4BSD is different
and causes much grief with which I am familiar with.  That is why I am glad
that most porting I do is from 4.XBSD to System V, and not the other
way around!  I assume you don't get out from under 4.XBSD that often huh?

-- 
Adelphi University, Garden City, NY 11530                   (516) 663-1170
Department of Mathematics and Computer Science
                                 markd@adelphi.UUCP  or  mark@promark.UUCP
                      UUCP:      ...philabs!sbcs!bnlux0!adelphi!markd