NAME
	GPD_READEVENT -- Return the next game port event.

   FUNCTION
	Read game port events from the game port and put them in the
	data area of the iORequest.  If there are no pending game port
	events, this command will not be satisfied, but if there are
	some events, but not as many as can fill IO_LENGTH, the
	request will be satisfied with those currently available.

   IO REQUEST
	io_Message	mn_ReplyPort set if quick I/O is not possible
	io_Device	preset by the call to OpenDevice
	io_Unit		preset by the call to OpenDevice
	io_Command	GPD_READEVENT
	io_Flags	IOB_QUICK set if quick I/O is possible
	io_Length	the size of the io_Data area in bytes: there
			are sizeof(inputEvent) bytes per input event.
	io_Data		a buffer area to fill with input events.  The
			fields of the input event are:
	    ie_NextEvent
			links the events returned
	    ie_Class
			is IECLASS_RAWMOUSE
	    ie_SubClass
			is 0 for the left, 1 for the right game port
	    ie_Code
			contains any gameport button reports.  No
			report is indicated by the value 0xff.
	    ie_Qualifier
			only the relative and button bits are set
	    ie_X, ie_Y
			the x and y values for this report, in either
			relative or absolute device dependent units.
	    ie_TimeStamp
			the delta time since the last report, given
			not as a standard timestamp, but as the frame
			count in the TV_SECS field.

   RESULTS
	This function sets the error field in the iORequest, and fills
	the iORequest with the next game port events (but not partial
	events).

   SEE ALSO
	gameport.device/GPD_SETCTYPE, gameport.device/GPD_SETTRIGGER