Up until now, we have worked with standard type messages (e.g. strings). Let’s see how we can create our own custom messages in ROS.
Open a new terminal window, and type the following command to go to the noetic_basics_part_1 package:
Create a msg folder inside that package.
Move inside that folder.
Create a new .msg file
Add the following lines.
int32 A int32 B int32 C
Click Save and close out the window.
In the code above, we have written three message descriptions. Specifically, we have declared three signed 32-bit integers. The syntax for a message description is:
Now, go back to the package.
Open the package.xml file.
Uncomment these two lines by deleting the arrows on each side:
Click Save, and then close the editor.
Now open CMakeList.txt.
Add message_generation inside the find_package(catkin REQUIRED COMPONENTS…) scope.
Also uncomment the add_message_files (…) lines and add the name of the message you just created.
Now uncomment the generate_messages(…) lines.
Since we made all these changes, we now need to build the package.
Check to see if everything built properly by typing the following command:
rosmsg show noetic_basics_part_1/noetic_basics_part_1_msg
Here is what you should see:
You can also see the custom message you just created by typing this command:
The message types are listed in alphabetic order by package name.
You can also just see a list of message types for just the noetic_basics_part_1 package.
rosmsg package noetic_basics_part_1