PL SQL function to get the ADR HOME PATH

CREATE OR REPLACE FUNCTION getAdrHome
   RETURN VARCHAR
IS
   base   VARCHAR (10);
   home   VARCHAR (255);
BEGIN
   SELECT VALUE
     INTO base
     FROM v$diag_info
    WHERE name = 'ADR Base';

   SELECT SUBSTR (VALUE, LENGTH (base) + 2)
     INTO home
     FROM v$diag_info
    WHERE name = 'ADR Home';

   RETURN home;
END;
/

To use this function

select getAdrHome from dual;