# PX4_MSGS The [PX4_msgs](https://github.com/PX4/px4_msgs) package is required, because it translates [[Custom uORB Message|uORB]] messages into the ROS2 ecosystem and vice versa. The project contains a `msg` folder, which contains the msg definitions. Usually, those message definitions are autogenerated by [a script](https://github.com/PX4/PX4-Autopilot/blob/v1.13.3/msg/tools/uorb_to_ros_msgs.py) provided by the PX4-Autopilot project. A build error that has popped up several times is that the messsage definition comments contain `*/` which is misinterpreted by the compiler Error message: ``` bash /home/pi/ros2_ws/build/px4_msgs/rosidl_generator_c/px4_msgs/msg/detail/gimbal_v1_command__struct.h:356:3: error: expected identifier or ‘(’ before ‘/’ token 356 | */ | ^ /home/pi/ros2_ws/build/px4_msgs/rosidl_generator_c/px4_msgs/msg/detail/gimbal_v1_command__struct.h:365:3: error: expected identifier or ‘(’ before ‘/’ token 365 | */ ``` In order to solve this error, just delete the relevant parts of the comment. # px4_ros_com In order to successfully build the `px4_ros_com` package you need to define the following env-variable: `export FASTRTPSGEN_DIR="/usr/local/bin/"`. Without it it will not work and throw the following error: ```bash c++: error: /home/pi/ros2_ws/build/px4_ros_com/src/micrortps_agent/microRTPS_agent.cpp: No such file or directory c++: fatal error: no input files ```