03. Create a Workspace

Create a Catkin Workspace

Step 1: mkdir -p ~/catkin_ws/src

All of the ROS related code you develop throughout this course will reside in your catkin workspace. You only need to create and initialize the workspace once.

First, create the top level catkin workspace directory and a sub-directory named src (pronounced source). The top level directory’s name is arbitrary, but is often called catkin_ws (an abbreviation of catkin_workspace), so we will follow this convention. You can create these two directories with a single command: 

$ mkdir -p ~/catkin_ws/src

Step 2: cd ~/catkin_ws/src

Next, navigate to the src directory with the cd command: 

$ cd ~/catkin_ws/src

Step 3: catkin_init_workspace

Now you can initialize the catkin workspace: 

$ catkin_init_workspace

Let’s list the contents of the current directory to see what changed. 

$ ls -l

Notice that a symbolic link ( CMakeLists.txt ) has been created to /opt/ros/kinetic/share/catkin/cmake/toplevel.cmake

Step 4: cd ~/catkin_ws

Return to the top level directory, 

$ cd ~/catkin_ws

Step 5: catkin_make

and build the workspace.

Note : you must issue this command from within the top level directory (i.e., within catkin_ws NOT catkin_ws/src ) 

$ catkin_make

While it is not essential that you have a deep understanding of what the catkin build system is, particularly if you are doing most of your development work in Python, it is helpful to learn about it. The curious reader is encouraged to read the ROS wiki .

After the command is executed you will notice the output of the build processes being echoed to your display. When it has finished you should see the following lines at the end of the output: 

-- BUILD_SHARED_LIBS is on
-- Configuring done
-- Generating done
-- Build files have been written to: /home/robo/catkin_ws/build
####
#### Running command: "make -j2 -l2" in "/home/robo/catkin_ws/build"
####
robo@robo-virtual-machine:~/catkin_ws$

But what else has changed? Use the ls command again to see what is new. 

$ ls

You now have two new directories: build and devel . The aptly named build directory is the build space for C++ packages and, for the most part, you will not interact with it. The devel directory does contain something of interest, a file named setup.bash . This setup.bash script must be sourced before using the catkin workspace.

Step 6: Commentary

Congratulations! You just created your first catkin workspace.

Before you begin to work with and develop your own ROS package, you should take a moment to get acquainted with catkin workspace conventional directory structure as described in the ROS Enhancement Proposal (REP) 128: http://www.ros.org/reps/rep-0128.html

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