Re: [libvirt] [PATCH 01/13] Introduce a new public API for domain events

On 03/19/2010 09:38 AM, Daniel P. Berrange wrote: > Since different event types can received different data in the callback, > the API is defined with a generic callback. Specific events will each > have a custom signature for their callback. Thus when registering an > event it is neccessary to cast the callback to the generic signature > > > +/* A generic callback definition. Specific events usually have a customization > + * with extra parameters */ > +typedef void (*virConnectDomainEventGenericCallback)(virConnectPtr conn, > + virDomainPtr dom, > + void *opaque); Should the callback be allowed to return anything, as void*? For example, I've seen some programming paradigms where you can write a generic iterator that marches through callbacks for each item in a set, allowing an early abort of the iteration if any of the callbacks return a non-NULL value (useful for both finding the first element that matches a given criteria, and for gracefully aborting operations on first failure).