[AFS3-std] Callback Extended Information Draft 4

[Derrick Brashear]

On Wed, May 14, 2008 at 5:46 PM, Jeffrey Hutzelman <jhutz@cmu.edu> wrote:
> --On Wednesday, May 14, 2008 05:36:42 PM -0400 Matt Benjamin
> <matt@linuxbox.com> wrote:
>
>
> > Create AFSExtendedCallbackV2, which aggregates an AFSExtendedCallbackV1,
> > and then adds new members.  Create ExtendedCallbackV2 taking
> > AFSExtendedCallbackV2 as argument.
> >
>
>  Oh, you don't need to do that.  You _can_ gracefully extend the union, as
> long as you are willing to accept that calls made using a discriminator not
> known to the server you are calling will abort with RXGEN_SS_UNMARSHALL.
> This is the moral equivalent of a call to an RPC not supported by the server
> aborting with RXGEN_OPCODE, and is perfectly acceptable, given that you
> shouldn't be sending notifications with unknown types anyway.
>

one presumes new operation types would be the cause of new callback
types, and there'd be a capability bit anyway.