cygwin 3.1 pseudo console in PTY and break/ctrl-c handling

Thomas Wolff
Thu Feb 20 09:11:00 GMT 2020

On 19.02.2020 21:21, Brian Inglis wrote:
> On 2020-02-19 13:02, Kevin Schnitzius via cygwin wrote:
>> On Tuesday, February 18, 2020, 05:54:23 PM EST, Thomas Wolff wrote:
>>>> With 3.1.2-1:
>>>> mintty -o "CA+F12:break"               =====>    ctrl-alt-F12 causes a break and kills notepad
>>>> mintty -o "c:break"                    =====>    ctrl-shift-c causes a break and kills notepad
>>>> mintty -o "C+c:break"                  =====>  FAIL -- ctrl-c kills native apps but notepad is not affected
>>>> mintty -o "CA+c:break"                 =====>  FAIL -- ctrl-alt-c kills native apps but notepad is not affected
>>> This would be mintty -o KeyFunctions='CA+F12:break' etc.
>>> The latter two are not valid mintty configuration; Ctrl is only
>>> supported as a modifier for function keys and special keys, not letters.
>>> This is unchanged with the cygwin version.
>> Ah, thank you.  That was the clue that I needed.
>> For those also having this problem:
>> mintty.exe -o "KeyFunctions=c:break" -o CtrlExchangeShift=true -
>> will propagate Ctrl-C to the non-native apps and kill them, imitating the behavior of 3.0.X Cygwin.
>> Now that I have played with this for a while, I am thinking that I like the new behavior better and I have assigned a new key to specifically kill native Windows programs instead letting the Ctrl-C do all the work (I am using Alt-F5 to do this).
> Should the above settings not be the default behaviour for backward
> compatibility and least surprise to users?
I was just taking up the requester's example. Sure ^C is an interrupt 
function on the command line. This is handled by the pty driver, not by 
the terminal.
The above configuration is a mintty feature of assigning functions (of 
which break is just one special case) to key combinations, independent 
of the stty settings.

> It used to be mintty just worked as expected with most programs, now additional
> interfaces seem to be required depending on Windows versions, editions, and
> releases. These helpers should either be included in the package, or be
> dependencies pulled in by mintty without which it will not install, with the
> appropriate interfaces installed and configured so that mintty, shells, and
> programs run under it continue to work as expected.
Some recently reported observations are related to the ConPTY project. 
There have been no changes in mintty concerning keyboard handling.

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