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From: guy%gorodish@Sun.COM (Guy Harris)
Newsgroups: comp.unix.questions
Subject: Re: Keyboard Input (Revised Question) ...
Message-ID: <24383@sun.uucp>
Date: Wed, 29-Jul-87 01:16:54 EDT
Article-I.D.: sun.24383
Posted: Wed Jul 29 01:16:54 1987
Date-Received: Fri, 31-Jul-87 02:38:36 EDT
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> It should be noted here that VTIME takes affect *AFTER* the first character
> is received.

Unless VMIN is zero, in which case (under System V, but not under System
III), the timer is started when the "read" is done, and the "read" is
satisfied as soon as a single character arrives.  If VTIME is also
zero, the effect is the same as if you'd turned no-delay mode on; the
"read" is immediately satisfied regardless of whether there are any
characters present or not.

Of course, the person who asked the original question was using
machines that, most likely, have a 4BSD terminal driver, so none
of this is pertinent.  Furthermore, all they wanted to do was know
whether there was any input present; FIONREAD, which *is* available
under 4BSD, does this job better than either no-delay I/O or
VMIN/VTIME.
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com