status.i4.v = dio_controlling_device_c(device_indices.i4a.r,
					       errors.i2a.r, num_devices.i4.v)

	This routine returns the device (if any) which controls a device.
	If no controlling device exists, a value of zero will be returned
	for that entry.

	device_indices	device index or array of device indices
	controlling_dis	returned controlling device index or array of
			device indices
			(A value of NULL may be passed if no controlling devices
			 are needed.)
	errors		returned ACNET status value or array of status values
	num_devices	number of devices

	This function returns status values as follows:

	OK			success
	DIO_BADARG		invalid number of devices passed
	DIO_MEMFAIL		memory allocation failure
	negative value		ACNET format error indicating overall failure
	positive value		number of devices in error indicating partial

	This function requires the following include files:

	diolib_h, acnet_errors_h

	Related functions:

	dio_siblings, dio_family, dio_expand_family_c, dio_family_info(_c),

	C/C++ usage:

	short	errors[NUM_DEVICES];
	int	status;
	static const int	device_indices[NUM_DEVICES] = {14430, 14431};
	int	controlling_dis[NUM_DEVICES];
	int	num_devices = NUM_DEVICES;

	status = dio_controlling_device_c(device_indices,controlling_dis,