Hi Kangjin- Looking at your code, everything is correct. You just forgot to create and run the gen_number.py script as described in the third part of the tutorial series. http://www.ros.org/wiki/actionlib_tutorials/Tutorials/RunningServerAndClientWithNodes The server is waiting for data from the random number generator before it can compute the average requested by the goal from the action client. Thanks for the question. In the future please send your questions to ros-users@code.ros.org so that everyone can benefit from your questions :) The ROS community is very helpful and quick to answer questions. -Melonee On Fri, Dec 3, 2010 at 6:47 PM, Kangjin Kim wrote: > Dear MeloneeWise > > Hello, I am a student in computer science, Arizona State University. I > am learning ROS through your tutorial. I have a question on the > tutorial > actionlib_tutorial/Tutorials/SimpleActionServer(GoalCallbackMethod). > When I executed the client and the server, the server didn't give the > client the answer after getting the goal, in the goalCB routine. > > Adding debuging code, I could get that it didn't continue after goalCB. > > I, also, tried to change the duration to 60.0 of the client > code(averaging_client.cpp), and the result was same. > > Please, let me know what I was wrong. I am attaching my > learning_actionlib codes. > > Sincerely yours, > Kangjin Kim > -- Senior Engineer Intern Program Director Willow Garage 68 Willow Rd. Menlo Park, Ca 94025