Re: bin/47877 (tip(1) does not disable flow control)

[David Holland <dholland-bugs%netbsd.org@localhost>]

The following reply was made to PR bin/47877; it has been noted by GNATS.

From: David Holland <dholland-bugs%netbsd.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: bin/47877 (tip(1) does not disable flow control)
Date: Tue, 8 Oct 2013 06:04:00 +0000

 On Mon, Oct 07, 2013 at 07:15:01PM +0000, Michael van Elst wrote:
  >  On Mon, Oct 07, 2013 at 07:50:00AM +0000, David Holland wrote:
  > > >  The problem is fixed. The change however also modifies the IXANY flag
  > > >  which is questionable.
  > >  
  > >  That seems reasonable to me... it seems unlikely that anyone's going
  > >  to be using tip(1) over a vintage modem where IXANY allows line noise
  > >  to mess things up.
  >  
  >  It's not about line noise. When xon/xoff is used for flow control,
  >  any bidirectional protocol may prevent it from functioning and you
  >  have to rely on that protocol to recover from loss of input characters.
 
 I'm not sure I follow - most such protocols will also trigger xoff
 inadvertently and therefore you'd better disable xon/xoff before using
 them.
 
 also I'd hope in this day and age anyone doing stuff where this
 matters would be using a 7-wire cable.
 
 Anyway, if you think it's wrong or you have an application where it
 breaks, I'd just go ahead and change it, or maybe if feeling ambitious
 hack it so it switches off IXANY when spawning kermit/rz/whatever.
 Otherwise I'd leave it alone -- the biggest problem with xon/xoff in
 practice is that users trigger it by accident and don't know how to
 recover.
 
 -- 
 David A. Holland
 dholland%netbsd.org@localhost