We have to edit the CMakeLists.txt file in the package to compile and build the source code. Navigate to mastering_ros_demo_pkg to view the existing CMakeLists.txt file. The following code snippet in this file is responsible for building these two nodes:
include_directories( include ${catkin_INCLUDE_DIRS} ${Boost_INCLUDE_DIRS} ) #This will create executables of the nodes add_executable(demo_topic_publisher src/demo_topic_publisher.cpp) add_executable(demo_topic_subscriber src/demo_topic_subscriber.cpp) #This will generate message header file before building the target add_dependencies(demo_topic_publisher mastering_ros_demo_pkg_generate_messages_cpp) add_dependencies(demo_topic_subscriber mastering_ros_demo_pkg_generate_messages_cpp) ...