How can I post to ros's callbackQueue()?
Looking at the "Callbacks and Spinning" wiki, ROS apparently is using an event queue under the hood.
I would like to post a callback to this queue from within another callback.
Is this possible, and how do I do it?
Can you point me to example?
---Background ---
I have 4 callbacks that are processed. A,B,C, and D
Assume these get posted in FIFO order [C A D B].
I would like the first (C in the example) processed, to post another event E to the callback queue. So after processing, C, the queue should be [A D B E], so that A is processed next.
If I understand the wiki, I could call ros::spin() within the C callback function to process A-D-B, and then call E directly, but for various reasons I prefer to post a separate callback.
Thoughts?