*BSD News Article 10630


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From: caadams@polaris.unm.edu (Clifford A Adams)
Newsgroups: comp.unix.programmer,comp.unix.bsd
Subject: TERMIO/TERMIOS reliability on BSD-like systems.
Date: 1 Feb 1993 02:42:09 GMT
Organization: University of New Mexico, Albuquerque
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Distribution: world
Message-ID: <1ki2m1INNeea@lynx.unm.edu>
NNTP-Posting-Host: polaris.unm.edu
Summary: The trn newsreader prefers sgtty routines for BSD
Keywords: termio, termios, POSIX, terminal handling, BSD


	I am working on extensions to the trn newsreader, and found an
interesting configuration assumption.  Trn looks for (and uses) termio
or termios functionality before trying to use sgtty.h.  That is,
*unless* the system is a BSD type, in which case sgtty.h is looked for
first.  In trn 2.4, BSD-type means a Sun, ULTRIX, or Pyramid(?) system.
In trn 3.0 (still in testing), sgtty is looked for first for any
BSD-like system (that the new Configure knows about).

	My problem is that I would like to use the VMIN and VTIME
variables specified in the termio/termios behavior.  (I use them to
wait a short time for input before doing background processing, which
makes the program much more responsive to user input.)

	I contacted the author of trn, and he said sgtty was used
first because of concerns that the termio(s) handling on BSD systems
didn't always work properly, although he didn't know specifics.  I
found that both termio and termios worked properly on my (ULTRIX 4.2)
system, and I'm wondering if other systems still have problems.

	In other words: is it safe to rely on termio/termios with
BSD-like systems?  Since trn is used on a wide variety of systems I
want to be very safe.  Were there problems with termio/termios, and if
so, are there many installations out there with these problems?
(If, for instance, SunOs 3.x.y was still used by many people and it
had a problem, I'd like to know.)

				--Cliff