Attention: Answers.ros.org is deprecated as of August the 11th, 2023. Please visit robotics.stackexchange.com to ask a new question. This site will remain online in read-only mode during the transition and into the foreseeable future. Selected questions and answers have been migrated, and redirects have been put in place to direct users to the corresponding questions on Robotics Stack Exchange. Additional details are available here.

roscpp message callback threading?

asked 2011-04-17 14:10:38 -0600

Bart
856 ●15 ●18 ●36

updated 2011-04-17 15:52:50 -0600

tfoote

58457 ●128 ●550 ●526 http://www.ros.org/

If a simple node with ros::spin() in the main loop subscribes to two messages, will the message callbacks be called sequentially or be potentially processed in parallel?

Is the GlobalCallbackQueue global to all nodes/ROS, or just the node making the call?

I reviewed roscpp/Overview/Callbacks, and it indicates that there is a callback queue(s), but it doesn't confirm that one callback completes before the next callback is initiated.

edit retag flag offensive close merge delete

add a comment

1 Answer

Sort by » oldest newest most voted

answered 2011-04-17 16:15:06 -0600

tfoote

58457 ●128 ●550 ●526 http://www.ros.org/

All threading is local to processes.

All callbacks can be associated with a specific callback queue. All callbacks go into the default queue if not specified. A NodeHandle can have a custom callback queue associated with it, or specific callback registrations.

If you have a single thread servicing a callback queue. All will be serial.

Any specific callback will only be called after the last instance has finished, regardless of how many threads there are in the queue.

edit flag offensive delete link

add a comment

Question Tools

Stats

Asked: 2011-04-17 14:10:38 -0600

Seen: 1,284 times

Last updated: Apr 17 '11

roscpp message callback threading? edit

1 Answer

Question Tools

Stats

Related questions

roscpp message callback threading?