From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:51065)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <kraxel@redhat.com>) id 1ZVK3Z-0006SO-HN
	for qemu-devel@nongnu.org; Fri, 28 Aug 2015 09:51:02 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <kraxel@redhat.com>) id 1ZVK3V-0000y2-79
	for qemu-devel@nongnu.org; Fri, 28 Aug 2015 09:51:01 -0400
Received: from mx1.redhat.com ([209.132.183.28]:38417)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <kraxel@redhat.com>) id 1ZVK3V-0000xu-2E
	for qemu-devel@nongnu.org; Fri, 28 Aug 2015 09:50:57 -0400
Message-ID: <1440769854.20725.4.camel@redhat.com>
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Fri, 28 Aug 2015 15:50:54 +0200
In-Reply-To: <E37F6880-6876-4625-8F22-9F8A939B8F91@gmail.com>
References: <57FA8C0D-64FF-4F71-8597-E36E0D1FF7E4@gmail.com>
	<1440762638.20725.0.camel@redhat.com>
	<22A8CA8A-8690-4670-93BC-096C96FB3950@gmail.com>
	<20150828133550.GQ28526@redhat.com>
	<E37F6880-6876-4625-8F22-9F8A939B8F91@gmail.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH] hw/usb/bus.c: print device ID when 'info
 usb' used
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Programmingkid <programmingkidx@gmail.com>
Cc: qemu-devel qemu-devel <qemu-devel@nongnu.org>

On Fr, 2015-08-28 at 09:39 -0400, Programmingkid wrote:
> On Aug 28, 2015, at 9:35 AM, Daniel P. Berrange wrote:
> 
> > On Fri, Aug 28, 2015 at 09:08:12AM -0400, Programmingkid wrote:
> >> 
> >> On Aug 28, 2015, at 7:50 AM, Gerd Hoffmann wrote:
> >> 
> >>> On Mo, 2015-08-24 at 15:13 -0400, Programmingkid wrote:
> >>>> +            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s
> >>>> Mb/s,"
> >>>> +                                "Product %s, ID %s\n",
> >>>> +                           bus->busnr, dev->addr, port->path,
> >>>> +                           usb_speed(dev->speed),
> >>>> +                           dev->product_desc, dev->qdev.id);
> >>>> 
> >>> 
> >>> dev->qdev.id can be NULL.
> >>> 
> >>> cheers,
> >>> Gerd
> >> 
> >> That isn't a problem. It will just say "null" when it is printed.
> >> No crash or garbage text.
> > 
> > Handling of '%s' with NULL is undefined by the standard. Linux
> > glibc prints the string "null", but other implementations can
> > crash.
> 
> "null" is also printed on Mac OS X. 
> 
> Do you want dev->qdev.id replaced with this? (dev->qdev.id != NULL) ? dev->qdev.id : "null"

Even better: Don't print "ID: ..." in the first place in case it is not
present.

cheers,
  Gerd