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Date: Sat, 31 Aug 2024 14:57:07 +0800
Message-ID: <CAEo=LZ8Szmr8e9MU3_CgOWjv0vYVNim-=Zjro6HEfXeTZYYbuw@mail.gmail.com>
Subject: Re: cygwin application on MsTerminal, enabling win32-raw-mode results
 in runway memory/CPU usage.
To: Takashi Yano <takashi.yano@nifty.ne.jp>
Cc: cygwin@cygwin.com
From: Adamyg Mob via Cygwin <cygwin@cygwin.com>
Reply-To: Adamyg Mob <adamyg.mob@gmail.com>
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I raised the same question under:
https://github.com/microsoft/terminal/issues/17824

*cons_master_thread() should *possibly maintain a local key cache and not
push back events.
Alternatively, from research these pseudo key events have Vk=0/Sc=0 values
(only char and down are set);  as such peek the console input queue and
don't process the input stream if detected.

Note,
WriteInputConsole is now considered as a *wrong-way verb
<https://learn.microsoft.com/en-us/windows/console/console-buffer-security-and-access-rights#wrong-way-verbs>*
for this buffer.
Applications remoting via cross-platform utilities and transports like SSH
may not work as expected if using this API
https://learn.microsoft.com/en-us/windows/console/writeconsoleinput

On Sat, Aug 31, 2024 at 1:20 PM Takashi Yano <takashi.yano@nifty.ne.jp>
wrote:

> Thanks for the pointer. Unfortunately, the document does not mention
> about the behaviour of WriteConsoleInput() in the win32-inpu-mode.
>
> I expected that ReadConsoleInput() returns the INPUT_RECORDS which
> WriteConsoleInput() sends. However, that does not seem true in this
> mode.
>
> On Sat, 31 Aug 2024 12:24:46 +0800
> Adamyg Mob wrote:
> >  *One suspect is the fhandler_console::cons_master_thread (), which
> > attempts to mine signals within the input stream; yet it may not handle a
> > single key being represented by multiple events.*; furthermore one of the
> > few uses of WriteConsoleInput
> > Is there any means of disabling the feature for testing?
>
> There is no other means than modifying the source code of cygwin1.dll
> and rebuild it. I already tried that and the problem disappeard.
>
> --
> Takashi Yano <takashi.yano@nifty.ne.jp>
>

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