status.i4.v = dio_siblings(device_indices.i4a.r, previous_dis.i4a.r,
				   next_dis.i4a.r, errors.i2a.r

	This routine returns previous and next siblings for a device.
	If "num_devices" is specified, siblings for a list of devices
	can be retrieved.  If a given sibling does not exist, a value
	of zero will be returned for that entry.

	device_indices	device index or array of device indices
	previous_dis	returned previous sibling device index or array of DIs
			(A value of NULL may be passed if no previous devices
			 are needed.)
	next_dis	returned next sibling device index or array of DIs
			(A value of NULL may be passed if no next devices
			 are needed.)
	errors		returned ACNET status value or array of status values
	[num_devices]	number of devices (default is 1)

	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_family, dio_family_info(_c), error_in_list(_c),
	dio_enable_obsolete_dev_info, dio_disable_obsolete_dev_info

	C/C++ usage:

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

	status = dio_siblings(device_indices,previous_dis,next_dis,