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From: laser-lovers@uw-beaver
Newsgroups: fa.laser-lovers
Subject: Re: 8 bit output (only) in 4BSD for (eg) LaserJet
Message-ID: <782@uw-beaver>
Date: Wed, 6-Feb-85 14:47:53 EST
Article-I.D.: uw-beave.782
Posted: Wed Feb  6 14:47:53 1985
Date-Received: Thu, 7-Feb-85 03:48:15 EST
Sender: daemon@uw-beaver
Organization: U of Washington Computer Science
Lines: 28

From: Chris Torek <chris@maryland>

If you need only 8 bits of output (that is, if you can stand 7 bit input)
then all you need to do to an ordinary tty line is:

#include <sgtty.h>

seteightbits(ttyfd)
int ttyfd;
{
	int bits;
	struct sgttyb sg;

	bits = LLITOUT;
	if (ioctl(ttyfd, TIOCLBIS, &bits))
		return (-1);	/* something went wrong */
	/* theoretically we're done now, but most 4BSD drivers have a
	   small bug, which we get around as follows: */
	if (ioctl(ttyfd, TIOCGETP, &sg) || ioctl(ttyfd, TIOCSETN, &sg))
		return (-1);
	return (0);		/* success */
}

You can eliminate the bug-workaround if your driver calls its param()
routine on TIOCLBIS ioctl()s.  (Most of them only do it for TIOCSETN
and TIOCSETP; you should add TIOCLBIS, TIOCLBIC, and TIOCLSET to fix.)

Chris