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.

Revision history [back]

ROS doesn't have any concept of calling a callback only when the data changes; callbacks are called whenever a new message is published, and the publisher is responsible for the semantics of when new messages are published.

If you want to detect when the data changes, you'll have to implement that yourself.

ROS Answers is licensed under Creative Commons Attribution 3.0 Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.