xsetpointer is used to change the device controlling the core pointer and to list available extended devices.
xsetmode is used to change the mode (absolute or relative) of an extended device. The device has to support relative and absolute modes and the device must not control the core pointer.
Consult the man pages for details.
$XFree86: xc/programs/Xserver/hw/xfree86/doc/sgml/xinput.sgml,v 3.6.2.1 1998/11/04 15:19:07 hohndel Exp $ $XConsortium: xinput.sgml /main/3 1996/10/27 11:06:13 kaleb $