Are terminal writes atomic?

[Mark J. DeFilippis]

In article <19972 at mimsy.UUCP>, chris at mimsy.UUCP (Chris Torek) writes:
> In article <186 at promark.UUCP> mark at 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
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