[libvirt] Raising events for testing

[Daniel P. Berrange]

On Fri, Jan 28, 2011 at 04:17:21PM +0100, arnaud.champion at devatom.fr wrote:
> I suffer with the new callback API :)
> 
> Does the new callback API need the EventRegisterImpl call ?

Yes, virEventRegisterImpl is required in order to be able to
receive events.

> Can anyone explain me the steps to install these callbacks ? I have
> a lot of difficulties to understand the polling process in the
> sample, does this polling is mandatory ?

Events can arrive at the client socket from libvirtd at
any time. The poll() is used to watch for events arriving
and ensure immediate dispatch. If we didn't do this no
events would be seen until the next API call was made
which is sub-optimal.

The file daemon/events.c shows a complete C implementation
of the event callbacks.

The file examples/domain-events/events-python/domain-events.py
shows a pure Python implementation

The C example program is a very *bad* demo of poll() so ignore
that and look at daemon/events.c instead.

Daniel