Writing a Simple Service and Client

 

srv structure

Server

 

bool add(); == This function provides the service for adding two ints, it takes in the request and response type defined in the srv file and returns a boolean.

res.sum = req.a + req.b; == two ints are added and stored in the response.

 

Client

srv.request.a = atoll(argv[1]);  == we instantiate an autogernerated service calss, and assign values into its request members.

if (client.call (srv)) == This actually calls the service. Since service call are blocking it will return once the call is done. If the service call succeeded, call() will return true an d the value in srv.response will be valid. if the call didn't succeed , call() will return false and the value in srv.response will be invalid.

add these 6 lines to make executables. by default they will go to directory of your devel space.  ~/catkin_ws/devel/lib/<package name>/

adding 10 20 with service and client module