how to monitor topic, when a certain topic not exist?
Hello,
I want to do a such thing : To monitor a topic . When everything is OK, a certain topic is always published by node A at a rate. when something wrong ,the node A is died,and the topic does not exist .At this time ,how can i know this topic exist or not ?
Does ROS has such API to monitor a topic ,when it does not exist ,notify me and i can use this signal to do something i want.
Any suggestions will be appreciated ,thank you very much !!!