How to get the current cursor of a Window?

[Phillip Bushee]

I can set the cursor to be displayed on a window in a
XSetWindowAttributes(3) structure while creating a window,
or with XDefineCursor(3) after the window is created.

But how can I get the current cursor of a window?
The XWindowAttributes(3) structure does not contain a Cursor
entry, so I cannot query it with XGetWindowAttributes(3).

Thanks in advance.