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Re: [Qemu-devel] printf in qemu
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] printf in qemu |
Date: |
Thu, 30 Jan 2014 10:08:50 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Jan 30, 2014 at 12:16:26PM +0500, Ayaz Akram wrote:
> I observed that if i place printf in qemu at certain places like in
> hw./serial.c file, I can see the printing when my guest OS is running on
> qemu, while there are some other places like in pckbd.c (emulation of
> keyboard), where if printf is used, I am not able to see any printing while
> guest OS is running, but when I press ctrl+A and x i can see that
> printing...... Any idea why this different behavior ??
Usually the problem is stdout buffering. See fflush(3) and use
fprintf(stderr) instead for debugging. stderr is unbuffered by default
on POSIX systems. I think on Windows you need to explicitly disable
buffering for stderr.
Stefan