From: Stefan Hajnoczi <stefanha@gmail.com>
To: Ayaz Akram <aaqemu@gmail.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] printf in qemu
Date: Thu, 30 Jan 2014 10:08:50 +0100 [thread overview]
Message-ID: <20140130090850.GB7619@stefanha-thinkpad.redhat.com> (raw)
In-Reply-To: <CAC0+NVaONKuxevS33Ua6h_AUT+gkXFffP8HyZmsiJyypsMN2Sw@mail.gmail.com>
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
prev parent reply other threads:[~2014-01-30 9:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-30 7:16 [Qemu-devel] printf in qemu Ayaz Akram
2014-01-30 9:08 ` Stefan Hajnoczi [this message]
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