library  db2dlib;

 uses 
  SysUtils,
  Classes;

 type 
  PInteger = ^Integer;

 procedure  IsDate(Value: PChar; Result: PInteger;
  Value_Null: PInteger; Result_Null: PInteger); stdcall;
 const 
  VALUE_IS_NULL = - 1 ;
 begin 
   if  Value_Null^ = VALUE_IS_NULL  then 
    Result_Null^:= VALUE_IS_NULL
     else 
     try 
      StrToDate( string (Value));
      Result^:=  1 
     except 
      on E: Exception  do 
        Result^:=  0 
       end 
 end ;

 exports 
  IsDate index  0 ;

 begin 
 end .

CREATE FUNCTION EXP.IS_DATE(VARCHAR( 10 ))
  RETURNS SMALLINT
  EXTERNAL NAME 'db2dlib!IsDate'
  LANGUAGE C
  PARAMETER STYLE DB2SQL
  DETERMINISTIC
  NO SQL
  NO EXTERNAL ACTION

VALUES(EXP.IS_DATE('01.01.2005'))