Msg Dependencies in Catkin
I'm new to writing packages in ROS and am confused about message dependencies in catkin.
If I'm going to use the turtlesim/Velocity.msg, what do I have to include in my CMakeLists.txt and my package.xml files? I am not writing my own msg - I simply want to publish turtlesim/Velocity messages to a topic.
In Section 1.3 in the http://www.ros.org/wiki/ROS/Tutorials/WritingPublisherSubscriber%28c%2B%2B%29 (Writing a Simple Publisher and Subscriber) tutorial, it says you are supposed to add this to the CMakeLists.txt file:
generate_messages(DEPENDENCIES std_msgs)
When I did that tutorial, I was able to run my talker and listener without adding that line; in fact, when I DID add that line and ran catkin_make, I got an error saying
Unknown CMake command "generate_messages"
Please let me know how I can fix my dependencies, and also if I should worry about "generate_messages" creating an error.
Thanks for your help!