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From: ds@sei.cmu.edu (Donald Stone)
Newsgroups: comp.emacs
Subject: Discard_Tty_Input
Message-ID: <2166@aw.sei.cmu.edu>
Date: Wed, 12-Aug-87 15:53:58 EDT
Article-I.D.: aw.2166
Posted: Wed Aug 12 15:53:58 1987
Date-Received: Sat, 15-Aug-87 01:33:38 EDT
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In emacs 18.41: 

  In sysdep.c, the routine discard_tty_input seems to flush the input
  buffer with the following two statements:

    ioctl (0, TIOCGETP, &buf);
    ioctl (0, TIOCSETP, &buf);

  I believe this gets the terminal state, and sets the terminal state
  to the same thing, with the side effect of flushing the input
  buffer.

  Unfortunately, on the Apollo (sr9.5), this also has the side effect
  of setting ^Q/^S control flow.  Oops.

  However, it seems there is an ioctl parameter, TIOCFLUSH, which
  flushes the tty input buffer.  When I replace the pair of calls with
 
    ioctl (0, TIOCFLUSH, &buf);

  everything seems to work fine.  

  Does anyone who knows the ioctl calls and this piece of emacs know
  if this is correct?  Or have I missed something?

Thanks,

   Don Stone (ds@sei.cmu.edu)
   Software Engineering Institute
   Carnegie-Mellon University
   Pittsburgh, PA
   (412) 268-7606