XnUserID ROS source code
While looking at the source code for openni_tracker.cpp, I came across a class called XnUserID. I cannot find the constructor for the class, and I have found nothing about it on the internet. Could someone post the constructor for XnUserID as well as its functions, or at least tell me where I can find it?
On a side note, what is Xn supposed to mean? It is in a lot of the code for ROS packages.