This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] pointers in public headers

To: Jan Beulich <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] pointers in public headers
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Fri, 25 Aug 2006 16:25:47 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Fri, 25 Aug 2006 08:26:01 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <44EF2FA2.76E4.0078.0@xxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcbIWrz9+5jEsDRNEdut6gAKle7CWA==
Thread-topic: [Xen-devel] pointers in public headers
User-agent: Microsoft-Entourage/
On 25/8/06 4:13 pm, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:

> Yes, they present a lurking problem once the converted structures get
> accessed - clearly any kind of pointer is invalid when considering
> compatibility
> mode guests. I could certainly try to make the script catch them and convert
> them (to a integer type), but then the automation of copying the respective
> fields will trigger compiler warnings about converting integrals to/from
> pointers of different size.
> So, yes, some kind of macro would help, but I can't see how you would
> want to get away with not breaking API compatibility (which requires to
> leave a pointer in there somehow) but eliminating the pointer.

I don't know enough about the scheme you are implementing to be able to
comment. I mean API compat from the p.o.v. of guests -- any macro would only
be defined as other than a plain pointer for Xen and your scripts, which
would presumably know what they're doing and avoid compile warnings.

 -- Keir

Xen-devel mailing list