Thanks for your reply.
On Ubuntu 10.04, I've already have 2 cursor, each for one mouse.
My problem is that, I expect GenericEvent( in X.h file), so I can transfer them to XI2( in XI2.h file) defined event.
But now, all event type is the the ones defined in X.h, like KeyPress, ButtonRelease, but never GenericEvent.

in the simpliest command line program, I can get the XI2 event.
But for the program in Qt, only the X2 event could be received. (see my sample code of X11Event() )
but I've check XI2 ,and my Qt program tells me that
XI2 supported. Server provides version 2.0.
For everything related to event capture is the same.
So as the beginning, I thought it maybe the link file problem.(but now, it seems not.)

For your second question, all my event is native, from X11 Event, for sure. [just they are not the extention case(XI2)]