public class wae_auslesen
    { 
        public static String wae_huf(Int16 v_mon, Int16 v_year)
        {
             ...

fhandle := ORA_FFI.REGISTER_FUNCTION(get_huf_lhandle, 'wae_auslesen.wae_huf', ORA_FFI.C_STD);

PACKAGE BODY GET_HUF IS
  get_huf_lhandle ORA_FFI.LIBHANDLETYPE;
  to_power_fhandle ORA_FFI.FUNCHANDLETYPE;
  
  test NUMBER;
  
  FUNCTION FF_TO_POWER(fhandle ORA_FFI.FUNCHANDLETYPE, v_month NUMBER, v_year NUMBER) RETURN VARCHAR2;
  PRAGMA interface(C, ff_to_power, 11265);
  
  FUNCTION GET(v_month NUMBER, v_year NUMBER) RETURN VARCHAR2 IS
  BEGIN
  	RETURN(FF_TO_POWER(to_power_fhandle, v_month, v_year));
  END GET;
    
BEGIN
	get_huf_lhandle := ORA_FFI.LOAD_LIBRARY('','gethuf.dll');
	test := 1;
	
	to_power_fhandle := ORA_FFI.REGISTER_FUNCTION(get_huf_lhandle, 'wae_auslesen.wae_huf', ORA_FFI.C_STD);
	test := 2;
	ORA_FFI.REGISTER_PARAMETER(to_power_fhandle, ORA_FFI.C_DOUBLE);
	test := 3;
	ORA_FFI.REGISTER_PARAMETER(to_power_fhandle, ORA_FFI.C_DOUBLE);
	test := 4;
	
	ORA_FFI.REGISTER_RETURN (to_power_fhandle, ORA_FFI.C_CHAR_PTR);
	test := 5;
EXCEPTION
	WHEN Ora_FFI.FFI_ERROR THEN
		DEV_MSG(tool_err.message,1);
		tool_err.pop;
	WHEN others THEN
		DEV_MSG('PRZ: GET_HUF.GET - ' || test || '#' ||SQLERRM,1);  	
END;