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

[Eric Blake]

On 12/13/18 6:21 AM, Wainer dos Santos Moschetta wrote:
> On 12/12/2018 08:04 PM, 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).

> >           if (!QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)) {
> > -            printf("%"PRId64" is not a sector-aligned value for 
> > 'count'\n",
> > -                   count);
> > +            fprintf(stderr,
> > +                    "%"PRId64" is not a sector-aligned value for 
> > 'count'\n",
>
> Adding one space before and after PRId64 as in '"%" PRId64 " is not 
> (...)"' increases readability IMHO.

Pre-existing, but I don't mind fixing it while touching in the area.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org