On 07/01/2013 03:20 PM, Jim Fehlig wrote:
> What I'm really not sure about is patch 03, which is
something I need
> if I want
> patch 04 to function properly. Basically it is about advertising that
> the libxl
> driver supports VIR_TYPED_PARAM_STRING. I looked at how that is done
> in the
> qemu driver, but I'm not entirely sure I completely understood the
> logic behind
> it, so, please, tell me if I missed or misinterpreted anything!
I think we'll need another libvirt dev more familiar with this to
verify, but afaict advertising that the driver supports
VIR_TYPED_PARAM_STRING is required when returning a string in
virTypedParam, for compatibility with older libvirt clients. Without it,
strings wouldn't be returned to newer clients that support
VIR_TYPED_PARAM_STRING.
Any new API added after VIR_TYPED_PARAM_STRING was added can
unconditionally assume that all callers are prepared to handle the
string. But for APIs that were created before string support was added,
even if your driver doesn't implement the API until now, you are correct
that you must advertise support for strings before returning any
strings. About the only API I know of off-hand that uses typed
parameters but was added after string support is the latest incantation
of migration via parameters.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library
http://libvirt.org