How do you determine the number of messages left in your subcriber buffer queue?

asked 2016-12-06 16:45:33 -0500

Grim
31 ●2 ●3 ●5

updated 2016-12-07 06:57:38 -0500

If I have a subscriber with a buffer size of 10, and my callback has dealt with 3 messages, is there a way to access the number of messages left in the queue ( retrieve the value of 7 )?

Basically I want my subscriber to deal with a batch of messages, and then do some task once they have all come through, then deal with the next batch of messages, and then do the task again. I do not know the size of the batch of messages.

Ideally I just need an indication that the buffer is empty.

answered 2016-12-06 17:03:59 -0500

paulbovbel

4518 ●12 ●49 ●80 http://www.bovbel.com/

updated 2016-12-06 17:04:52 -0500

Push your messages shared_ptr to another data structure as they come in (such as std::queue), and do your batch processing there instead.

The inner workings of the ROS subscriber's message buffer are not exposed through the roscpp API.

edit flag offensive delete link

Comments

While I think this may be a solution, I don't know how to do it. I have not dealt with std::shared_ptr or std::queue. And I am not sure if learning it right now would be worth my time for this project. This also needs to be memory efficient since the messages themselves are quite large.