A device that can be focused returns information for input Class Focus when an XOpenDevice request is made. XGetDeviceFocus can generate BadDevice, and BadMatch errors. An invalid device was specified. The speci fied device does not exist or has not been opened by this client via XOpenInputDevice. This error may also occur if the specified device is the X keyboard or X pointer device.
Some numeric value falls outside the range of values accepted by the request.
Unless a spe cific range is specified for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can generate this error. BadWindow A value for a Window argument does not name a defined Window. This error may occur if an XGetDeviceFocus or XSetDeviceFocus request was made specifying a device that the server implementation does not allow to be focused.