Part1: Developing a ROS C++ package

Introduction

This introduces the various stages of developing a simple Robot Operating System (ROS) package in Linux. The main aim is to focus on some good practices that are required to make a ROS compatible package. Open up the terminal and type the following

• mkdir -p ~/catkin_ws/src ## This will simply create two folders src inside catkin_ws
• cd ~/catkin_ws/src
• catkin_create_pkg my_test_package roscpp std_msgs moveit_core

The catkin_create_pkg has to be understood careflly. The first argument is the name of the package (my_test_package) and the rest are dependencies roscpp, std_msgs and moveit. Each package would have its own dependencies and could be different. After executing the above three lines, the src folder would have two other important files viz., CMakeLists.txt and package.xml. For the time being, lets leave both these as it is but it would be interesting to take a look at both these files and how ROS has organized our dependencies (roscpp, std_msgs, moveit_core) in it. The final step is to do the following

• cd ~/catkin_ws
• catkin_make

The catkin_make is equivalent to

• cd ~/catkin_ws
• mkdir build
• cd build
• cmake ../src -DCMAKE_INSTALL_PREFIX=../install -DCATKIN_DEVEL_PREFIX=../devel
• make

At this stage the folder structure would be

catkin_ws
    |_ build/
    |_ deve/l
    |_ src/
        |_ CMakeLists.txt
        |_ my_test_pkg/
                |_ CMakeLists.txt
                |_ package.xml
                |_ src/
                |_ include/
                      |_ my_test_pkg/

We will organize and add our c++ header files in include/my_test_package and all c++ source files in src. Go to Part 2 for more exciting stuffs.