DMXGetInputCount - determine number of input devices
#include <X11/extensions/dmxext.h>
Bool DMXGetInputCount(Display *dpy,
int *input_count);
DMXGetInputCount() returns the number of input devices connected to the
Xdmx(1) server in input_count. This number is the same as that
returned by XListInputDevices(3), but is available even when the XInput
extension is not supported.
DMXGetInputCount() returns True unless there is a protocol error.
DMXGetInputAttributes(3), XListInputDevices(3), DMX(3),
Xdmx(1)