dio_get_pdb

	status.i4.v = dio_get_pdb(device_indices.i4a.r, properties.i2a.r,
				  pdbs.g.v, errors.i2a.r [,num_devices.i4.r]
				  [,pdb_lengths.i4a.r])

	This routine returns PDBs for specified devices and properties.
	There are three types of PDBs.  Each type must be accessed in distinct
	function calls.  Only reading and setting PDBs may be requested in
	the same call.
	
	device_indices	device index or array of device indices
	properties	property index or array of property indices
			(PRREAD -> reading property,
			 PRSET -> setting property,
			 PRBSTS -> basic status property,
			 PRBCTL -> basic control 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.)
	pdbs		array of "num_devices" PDB structures returned in
			the caller's data space of type:
			(reading (PRREAD) -> PDB_RS structure,
			 setting (PRSET) -> PDB_RS structure,
			 basic status (PRBSTS) -> PDB_STS structure,
			 basic control (PRBCTL)	-> PDB_CON structure)
			(types are in cns_data_structs include file)
			(If a value of NULL is passed for this argument, no
			 PDBs will be returned to the caller, but they will
			 be cached in the program's memory for later use.)
	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
			returned.)
	[num_devices]	number of devices in the list (default is 1)
	[pdb_lengths]	returned number of bytes actually used in each PDB
			(default is NULL)

	This function returns status values as follows:

	OK			success
	DIO_BADARG		invalid property index or combination of
				property indices was 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, cns_data_structs_h, diolib_h, acnet_errors_h

	Related functions:

	mng_diopool, dio_get_extended_pdb_c, 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;
	int	pdb_lengths[NUM_DEVICES];
	PDB_RS	pdbs[NUM_DEVICES];

	status = dio_get_pdb(device_indices,&properties,(void *) pdbs,
			     errors,&num_devices,pdb_lengths);