status.i4.v = dio_db_extrema_c(device_indices.i4a.r, properties.i2a.r,
				       min_values.r8a.r, max_values.r8a.r,
				       errors.i2a.r [,num_devices.i4.v])

	This routine returns the maximum and minimum scaled values for
	a device or a list of devices.
	device_indices	device index or array of device indices
	properties	property index or array of property indices
			(PRREAD -> reading property,
			 PRSET -> setting property)
			(If the first value is less than zero, all devices
			 use a property index which is equal to the absolute
			 value of this argument.)
	min_values	returned minimum scaled value or array of
			minimum values (a value of NULL will result
			in no minimum values being returned)
	max_values	returned maximum scaled value or array of
			maximum values (a value of NULL will result
			in no maximum values being returned)
	errors		returned ACNET status value or array of returned
			status values (A status of DBM_NOREC indicates that
			the requested PDB does not exist even though the
			requested property does exist.  If the property
			itself doesn't exist, a status of DBM_NOPROP is
	[num_devices]	number of devices in the list (default is 1)

	This function returns status values as follows:

	OK			success
	DIO_BADARG		invalid property index passed
	DIO_MEMFAIL		memory allocation failure
	negative value		other ACNET format error
	positive value		number of devices in error

	This function requires the following include files:

	dbprops_h, diolib_h, acnet_errors_h

	Related functions:

	dio_extrema(_c), dio_manage_extended_pdbs_c, dio_extended_pdb_c,
	dio_get_pdb, dio_delete_pdb, dio_insert_pdb_lst, dio_delete_pdb_lst,
	dio_pdb_to_scaling_info_c, dio_pdb_sts, dio_pdb_ctl, dio_scaling,
	dio_get_historic_scaling_c, dio_data_type_info_c, error_in_list(_c)

	C/C++ usage:

	short	errors[NUM_DEVICES];
	short	properties = -PRSET;
	int	status;
	static const int	device_indices[NUM_DEVICES] = {14430, 14431};
	int	num_devices = NUM_DEVICES;
	double	min_values[NUM_DEVICES];
	double	max_values[NUM_DEVICES];

	status = dio_db_extrema_c(device_indices,&properties,min_values,