example_ros_msg

Example ROS (Robot Operating System) messages are structured data that communicate between different components in a ROS system. They are typically defined using message files (`.msg` or `.sdf` format), which describe the fields and types of data they contain.

To demonstrate an example, let's consider a simple `std_msgs/Int32` message, often used to send integers:

<launch>
  <node pkg="std_msgs" type="publisher" name="int_publisher">
    <topic name="int_topic" type="std_msgs/Int32">
      <message>
        <int32>42</int32> <!-- Example integer value -->
      </message>
    </topic>
  </node>
</launch>

[^4]: The above XML snippet shows how you can define a publisher node in a ROS launch file, which sends an Int32 message with the value of 42 on the "int_topic".

In code, you might publish this message like this:

import rclpy
from std_msgs.msg import Int32

def main(args=None):
rclpy.init(args=args)
node = rclpy.create_node('int_publisher')

msg = Int32(data=42)
pub = node.create_publisher(Int32, 'int_topic')

while rclpy.ok():
pub.publish(msg)
rclpy.spin_once(node)

if __name__ == '__main__':
try:
main()
except Exception as e:
rclpy.logging.error('Exception:', cause=e)
rclpy.shutdown()

This creates a publisher that sends `Int32` messages with the value 42 every time the loop runs.