Re: [Qemu-devel] Win32 stdio not working if SDL is enabled

[Stefan Weil <sw@weilnetz.de>]

Am 13.08.2015 um 14:06 schrieb Daniel P. Berrange:
> When debugging some patches on Windows, I discovered that nothing printed
> to stderr ever appears on the console. Eventually I discovered that if I
> build with --disable-sdl, then stderr appears just fine.
> 
> Looking at the code in vl.c I see a hack for SDL introduced in
> 
>   commit 59a36a2f6728081050afc6ec97d0018467999f79
>   Author: Stefan Weil <weil@mail.berlios.de>
>   Date:   Thu Jun 18 20:11:03 2009 +0200
> 
>     Win32: Fix compilation with SDL.
> 
> 
> If I mostly kill the hack from vl.c, and just leave a plain '#undef main'
> then I get working console stderr once again.
> 

Hi Daniel,

that's a feature of SDL 1.2: stdout and stderr are by default
redirected to files stdout.txt and stderr.txt in the executable's
directory.

This redirection can be disabled by an environment variable
(SDL_STDIO_REDIRECT="no"). On my Linux machines, I always
set this variable, so when I run QEMU for Windows with
wine32 or wine64, stdout and stderr work.

Printing to stdout / stderr on Windows can be an adventure:
depending on your shell (command.exe, cmd.exe, MinGW shell,
MinGW rxvt, Cygwin shell, ...) it works different, and I also
had application crashes when a GUI application which was
not started from a shell tried to print to stdout.

>From a user's point of view, maybe a better solution than
the current one would be a GTK console window which displays
any output to stdout / stderr.

Regards
Stefan