Cygwin doesn't handle SIGWINCH properly in Windows Terminal

[Thomas Wolff]

Am 16.02.2021 um 21:37 schrieb Takashi Yano via Cygwin:
> On Tue, 16 Feb 2021 09:26:52 -0700
> Brian Inglis wrote:
>> On 2021-02-16 04:31, Takashi Yano via Cygwin wrote:
>>> On Tue, 16 Feb 2021 19:31:54 +0900
>>> Takashi Yano wrote:
>>>> On Sun, 14 Feb 2021 17:43:58 +0900
>>>> Takashi Yano wrote:
>>>>> On Sat, 13 Feb 2021 20:39:39 +1000
>>>>> Alvin Seville wrote:
>>>>>> Windows build number: Win32NT 10.0.19042.0 Microsoft Windows NT 10.0.19042.0
>>>>>> Windows Terminal version (if applicable): 1.5.10271.0
>>>>>> Script to reproduce this issue:
>>>>>> #!/usr/bin/env bashfunction outputText()
>>>>>> {
>>>>>>     local text=$1
>>>>>>     local -i textLength=${#text}
>>>>>>
>>>>>>     local -i line="$(tput lines) / 2"
>>>>>>     local -i col="$(tput cols) / 2 - $textLength / 2"
>>>>>>
>>>>>>     clear
>>>>>>     echo -en "\e[$line;${col}H$text"
>>>>>> }
>>>>>> trap "outputText 'Hello world!'" SIGWINCH
>>>>>> outputText 'Hello world!'while truedo
>>>>>>       :done
>>>>> This is because cygwin console handles SIGWINCH when the input
>>>>> messages is processed. If the process does not call either read()
>>>>> or select(), SIGWINCH will not be sent. This is the long standing
>>>>> problem of the implementation and hard to fix.
>>>> I came up with a solution for this issue and implemented that.
>>>> It seems working as expected as far as I tested while I did not
>>>> have to change the code much contrary to my concern.
>>>>
>>>> The point of the idea is to keep the basic structure of the
>>>> console code unchanged and introduce a new thread which handle
>>>> the only signals derived from input records. Handling of Ctrl-S
>>>> and Ctrl-Q also added.
>>>>
>>>> I would like to submit the patch to cygwin-patches mailing list.
>>>>
>>>> Corinna, could you please have a look?
>>> v2: Problems when input echo is stopped by Ctrl-S is fixed.
>> Do these changes (still?) honour stty flags like isig, ixany, noflsh and handle
>> interrupt character settings for e.g.:
>> 	intr = ^C; quit = ^\; swtch = ^Z; start = ^Q; stop = ^S; susp = ^Z;
>> 	discard = ^O;
>> ?
> Basically yes. However, stty noflsh, flusho and Ctrl-O
> does not take effect in the current code with/without
> the patch.
Output flushing doesn't work in the pty either, and neither in Linux. 
The setting seems to be a relic from Unix systems.