Re: [Qemu-devel] [PATCH RFC] qemu-io: Prefer stderr for error messages

[Kevin Wolf]

Am 13.12.2018 um 11:11 hat Daniel P. Berrangé geschrieben:
> On Wed, Dec 12, 2018 at 04:04:10PM -0600, Eric Blake wrote:
> > When a qemu-io command fails, it's best if the failure message
> > goes to stderr rather than stdout.
> > 
> > Reported-by: Richard W.M. Jones <address@hidden>
> > Signed-off-by: Eric Blake <address@hidden>
> > ---
> > 
> > RFC because at least iotest 60 (found by -qcow2 -g quick) breaks due
> > to reordering of output lines, and I'd rather know if we like this
> > idea before bothering to revisit all affected iotests (including
> > discovering if other slower ones have similar problems).
> 
> I think the change is correct. Error messages should never go to stdout.

I'm not sure about this, to be honest. qemu-io is first and foremost an
interactive program, and spreading output across two streams, one
buffered and one unbuffered, in an interactive program feels like it has
to result in surprises.

Kevin