If I am creating an addon that uses something like PAYPAL IPN (instant payment notification) which needs to do a 'callback' into the application - is it possible to use something like
api_register_func('myaddonname/ppipn-callback','my-callback-processor',false);
either in myaddon_init() or just inline in order to have paypal callbacks routed to my-callback-processor() (assuming my-callback-processor is not in a class)?
Is this the right way to do this? Is there a different approved/correct way to do this sort of thing?