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From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] handling SIGWINCH with qemu -nographic
Date: Tue, 16 Oct 2007 22:21:54 +0100
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To: qemu-devel@nongnu.org

> I think your question is quite reasonable. Imagine a Linux host
> running X Windows and a terminal like xterm or kconsole.
> Then run a program like "top" or "less" in this terminal.
> When a user changes the size of the console window, top, less
> and other console applications get notified of this change by SIGWINCH.
>
> Now run a similar program using QEMU's user mode emulation.
> Why should it not be possible to get SIGWINCH in QEMU and
> pass it on to the program in user mode emulation, so it can
> behave like a native Linux application and change its appearance?
>
> I don't think that implementing this is very difficult, so it will be
> done.

Try doing the same thing with a real machine connected via a serial port.
It won't work.

The difference is that for local applications (and remote terminals via telnet 
or ssh) you have OOB mechanisms to transmit event data (e.g. terminal size). 
A UART only gives you a simple serial connection. If you want things like 
terminal resizing to work you need to run some more complicated protocol over 
the serial link, with appropriate tty emulation on either end.

Paul