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Re: 1.7.9-1: typeahead queue not flushed when Ctrl+C pressed


On Mon, Apr 04, 2011 at 01:39:23PM -0500, Edward McGuire wrote:
>When I type ahead in an uncustomized terminal window, I expect my
>keyboard input to be queued until it is called for. When I press
>Ctrl+C, I expect the queue to be flushed. Any keyboard input still
>in the queue should be lost.
>
>The trouble I am having is that my keyboard input is preserved when
>I press Ctrl+C. I can easily reproduce the problem with the
>following keyboard input at a bash prompt:
>
>	$ tail -f /dev/null [Enter]
>	[Enter]
>	[Enter]
>	[Enter]
>	[Ctrl+C]
>
>If the typeahead queue is flushed by the Ctrl+C, then a bash prompt
>will appear. But if the queue is not flushed, then four bash prompts
>will appear. In my case, four bash prompts appear.
>
>I have reproduced the problem in a Cygwin (cmd.exe) window, in a
>mintty window, and in an xterm window.
>
>There is a termio mode bit, NOFLSH, which disables flush after
>interrupt. If this bit were set, it would explain why I am having
>the problem. But "stty -a" shows that this mode bit is not set. I
>checked this bit before and after reproducing the problem.
>
>I was still able to reproduce the problem after setting and clearing
>the NOFLSH bit with "stty noflsh; stty -noflsh".
>
>I have attached the output of "stty -a" below, along with the output
>of "cygcheck -s -v -r" and of "cat /var/log/xwin/XWin.0.log".
>
>I have not found this problem mentioned on the Cygwin list.
>
>Where might I be going wrong? Is this a limitation of the Cygwin
>termio?

Thanks for the testcase.  This was a limitation of the Cygwin DLL
but it should now be fixed in the latest snapshot:

http://cygwin.com/snapshots/

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