ros-visualization/visualization_tutorials — pull request #21 by VictorLamoine (2014-12-11 12:58:32+00:00)
Title: Check number of subscribers before publishing marker

This checks whether a node as subscribed to the marker topic and do not publish until someone subscribes.
Related [answers.ros.org](http://answers.ros.org/question/199299/why-do-i-need-to-enter-a-loop-to-display-a-marker/) topic.