Hi @thomaswang, I am afraid the Tobii Pro SDK is not compatible with the Tobii Eye Tracker 5.
If you wish to develop interaction applications with this tracker, then we would forward you to both the Tobii Stream Engine API and Interaction Library which
come with support for C# & C++ bindings.
You can check out the getting started guide @ https://developer.tobii.com/consumer-eye-trackers/stream-engine/
Check it out and let us know how you get on. Best Wishes.