posted on Thursday, October 14, 2010 - 06:14 pm
I'm very interested in developping DDS-based applications. However, I have difficulties to understand how we can send periodic data. Is it possible to define a QoS and the middleware takes in charge the periodic data sending? If yes, can you give a small example?
DDS can notify you that it is time to send an update for a particular periodic instance (you can use the deadlineQosPolicy on the DataWriter for that), but it can not send that update for you because it doesn't know what value to update the instance with.
However, you could use the callback from the on_offered_deadline_missed() operation of your listener to obtain the latest state for the instance in question and write it into the system.
Can you provide sort of a Use-Case why you want the DDS to update your instances automatically? How do you think the DDS should determine what value to update an instance with?