UnsatisfiedLinkError: libsensor_msgs__rosidl_generator_c.so

[tgrmev]

Describe the bug I got UnsatisfiedLinkError: libsensor_msgs__rosidl_generator_c.so. Is the problem related to ros2 or ros2-for-unity?

To Reproduce Steps to reproduce the behavior:

1. add image_pub = ros2Node.CreatePublisher<sensor_msgs.msg.CompressedImage>("image"); to talker.cs script

2. inside the lateUpdate() method `

       Texture2D snapshot = new Texture2D(resWidth, resHeight, TextureFormat.RGB24, false);
       snapCam.Render();
       RenderTexture.active = snapCam.targetTexture;
       snapshot.ReadPixels(new Rect(0,0,resWidth, resHeight), 0, 0);
       byte[] bytes = snapshot.EncodeToPNG();
   
       sensor_msgs.msg.CompressedImage ImageMsg = new sensor_msgs.msg.CompressedImage();
   
       ImageMsg.Data = bytes;
       ImageMsg.Format = "png";
       image_pub.Publish(ImageMsg);`

3. add a camera and link the render texture to camera
4. Link the talker.cs script and Unity Component.cs script to camera
5. Run the Unity simulation

Expected behavior First, I did not receive any error but after some time Unity freezed and I got the link error because of the sensor_msgs.

Desktop (please complete the following information):

• OS: [e.g. Ubuntu20.04]
• ros2 distro [foxy]
• ros2-for-unity version [latest]
• ros2cs version [latest]
• ros2 dds middleware [e.g. cyclonedds, fastdds]
• ros2 environment setup [single pc]

[pijaro]

I see that you are running the 1.1 version. Can you try the latest 1.2 release?

[tgrmev]

I also tried to ros2-for-unity-1.2.0 version. When I tried to run the unity with this version, I got this error :

NullReferenceException: Object reference not set to an instance of an object ROS2.ROS2UnityComponent.OnApplicationQuit () (at Assets/Ros2ForUnity/Scripts/ROS2UnityComponent.cs:160)

Also to give information, when I build the version 1.2.0, end of the building process I received this message :

Summary: 46 packages finished [7min 16s] 19 packages had stderr output: action_msgs actionlib_msgs builtin_interfaces diagnostic_msgs geometry_msgs lifecycle_msgs nav_msgs rcl_interfaces rosgraph_msgs sensor_msgs shape_msgs statistics_msgs std_msgs stereo_msgs test_msgs tf2_msgs trajectory_msgs unique_identifier_msgs visualization_msgs cp: cannot stat '/home/mev/UnityProjects/Unity-Ros2/ros2-for-unity-1.2.0_new/src/Ros2ForUnity/metadata_ros2cs.xml': No such file or directory cp: cannot stat '/home/mev/UnityProjects/Unity-Ros2/ros2-for-unity-1.2.0_new/src/Ros2ForUnity/metadata_ros2cs.xml': No such file or directory

[pijaro]

@tgrmev

Looks like the meta files were not generated properly.

Could you run

python3 ./src/scripts/metadata_generator.py

from the ros2-for-unity dir and see if src/Ros2ForUnity/metadata_ros2cs.xml and src/Ros2ForUnity/metadata_ros2_for_unity.xml files were generated?

[adamdbrw]

@tgrmev any luck following @pijaro advice?

[tgrmev]

hello, yes now i do not receive this error. Thanks.

[ynyBonfennil]

Since this issue is already closed, it might be pointless to write a comment, but I got a similar error UnsatisfiedLinkError: libstd_msgs__rosidl_typesupport_c.so in my personal project with ros2-for-unity v1.2.

The reason was because I instantiated std_msgs.msg.String before instantiating ROS2UnityCore (I created the message at Awake() but I instantiated ROS2UnityCore in Start()).

It seems like internal class ROS2ForUnity plays an important role for loading libraries but it won't be instantiated unless creating ROS2UnityCore first.