linux-kernel - Re: tty: ctrl-c not always echoed, especially under load

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Message-ID: <489A06D9.1080600@skyrush.com>
Date:	Wed, 06 Aug 2008 14:17:29 -0600
From:	Joe Peterson <joe@...rush.com>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
CC:	linux-kernel@...r.kernel.org
Subject: Re: tty: ctrl-c not always echoed, especially under load

Alan Cox wrote:
> If the output buffer is full then echoed characters/^C etc will vanish the
> way n_tty implements its buffering internally. It's always worked that
> way.

One more observation:

In Linux, try this:

# cat > foo
hi^Sthere^Q
^D

(in other words, during the cat into "foo", type "hi", hit ^S, then type
"there", then hit ^Q, then, on the next line, ^D to end the file)

Note that the "there" does not appear after hitting ^Q, but it does
appear in the file.  So the characters were accepted, but they were not
echoed (not even saved for echo when the terminal is restarted).

This behavior differs from that of FreeBSD (just tried it for fun -
haven't tried other Unix's yet).  I have noticed other times that the
echo seems to get lost while the tty is stopped.  Not sure if all this
is related, but something seems amiss.  Thoughts?

					Thanks, Joe
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