| Note: This tutorial assumes that you have completed the previous tutorials: ROS tutorials. |
 Please ask about problems and questions regarding this tutorial on answers.ros.org. Don't forget to include in your question the link to this page, the versions of your OS & ROS, and also add appropriate tags. |
Defining Custom Messages
Description: This tutorial will show you how to define your own custom message data types using the ROS Message Description Language.Tutorial Level:
Next Tutorial: Using a C++ class in Python
Generating Messages
Generating a message is easy. Simply place a .msg file inside the msg directory in a package. Please follow previous tutorial about creating .msg files (don't forget to choose build system type at the top of the page there).
Including or Importing Messages
C++
Messages are put into a namespace that matches the name of the package. ie.
Python
Dependencies
If you are using the new custom message defined in a different package, remember to add:
to manifest.xml:
<depend package="name_of_package_containing_custom_msg"/>
to package.xml:
<build_depend>name_of_package_containing_custom_msg</build_depend> <run_depend>name_of_package_containing_custom_msg</run_depend>
<build_depend>message_generation</build_depend> <run_depend>message_runtime</run_depend>
and you will need to add this to your CMakeList.txt:
find_package(message_generation) catkin_package(CATKIN_DEPENDS message_runtime) add_message_files(FILES your_msg_file.msg)
If you are building C++ nodes which use your new messages, you will also need to declare a dependency between your node and your message, as described in the catkin msg/srv build documentation
The ROSNodeTutorialPython tutorial shows an example of the previously described talker and listener tutorials using a custom message, with implementations in C++ and Python.
