Berkely unix (4.2) tty ioctl question

[Chris Torek]

If you do a TIOCSETP, that will wait for the output to drain; you
can then do TIOCSETC and SLTC and whatever else.  So you might do
something like this:

/* Change the terminal characters (start, stop, etc) after the output
   has drained.  Since 4.2 doesn't provide a set-after-wait ioctl for
   struct tchars, we have to use TIOCSETP to allow the output to drain.
   To do this we need a TIOCGETP so that we don't actually change
   anything.  Furthermore, someone should ensure that all this is done
   only in the foreground so that we don't get stopped and maybe have
   the tty characteristics change between the GETP and the SETP. */
SetCharsAfterWait (fd, t)
int fd;
struct tchars *t;
{
	struct sgttyb sg;

	(void) ioctl (fd, TIOCGETP, &sg);
	(void) ioctl (fd, TIOCSETP, &sg);
	(void) ioctl (fd, TIOCSETC, t);
}
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In-Real-Life: Chris Torek, Univ of MD Comp Sci (301) 454-7690
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