There is an Xlib routine called
XWarpPointer() that does this, but GDK does not
wrap it. It is almost certainly a bad idea to use this
feature (in fact it is intended for window managers
only); you might consider writing to one of the GTK+ or
Gnome mailing lists to ask for another way to achieve
whatever you are trying to achieve. However, you can
always use Xlib routines (such as
XWarpPointer()) by including
gdk/gdkx.h and
gdk/gdkprivate.h, then manipulating the private
parts of the GDK data structures. If that sounds
unsavory, it probably should.
