status.i4.v = dio_extrema(device_indices.i4a.r, properties.i2a.r,
				  min_values.g.v, max_values.g.v,
				  errors.i2a.r [,num_devices.i4.r]
				  [,units_text.i1a.r] [,convert_type.i4.r])

	status.i4.v = dio_extrema_c(device_indices.i4a.r, properties.i2a.r,
				    min_values.g.v, max_values.g.v,
				    errors.i2a.r [,num_devices.i4.v]
				    [,units_text.i1a.r] [,convert_type.i4.v])

	This routine returns the maximum and minimum scaled values for
	a device or a list of devices.  Please, note that the data type
	for the returned minima/maxima is dependent upon the conversion
	type selected.
	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
	[num_devices]	number of devices in list (default is 1)
	[units_text]	returned units text (default is NULL)
			(LEN_DEV_UNITS characters per device)
	[convert_type]	type of scaling conversion for extrema
			(DIO_COMMON -> return extrema in common engineering
				       units as single precision floats
			 DIO_COMMON_DOUBLE -> return extrema in common
					      engineering units as double
					      precision floats,
			 DIO_PRIMARY -> return extrema in primary units as
					single precision floats,
			 DIO_PRIMARY_DOUBLE -> return extrema in primary units
					       as double precision floats)

	This function returns status values as follows:

	OK			success
	DIO_BADARG		invalid property index passed
	DIO_MEMFAIL		memory allocation failure
	DIO_NOTYET		unsupported raw data type
	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_pdb_c, dio_extrema_pdb_ext_c, dio_scaling, dio_get_pdb,
	dio_data_len(_c), error_in_list(_c)

	C/C++ usage:

	char	units_text[NUM_DEVICES][LEN_DEV_UNITS];
	short	errors[NUM_DEVICES];
	short	properties = -PRSET;
	int	status;
	static const int	device_indices[NUM_DEVICES] = {14430, 14431};
	int	num_devices = NUM_DEVICES;
	int	convert_type = DIO_COMMON;
	float	min_values[NUM_DEVICES];
	float	max_values[NUM_DEVICES];

	status = dio_extrema_c(device_indices,&properties,(void *) min_values,
			       (void *) max_values,errors,num_devices,
			       (char *) units_text,convert_type);