Mensagem de retorno do código de erro no Oracle Stored Proc

CREATE OR REPLACE PROCEDURE "demo"."run_demo"(v_sql IN VARCHAR2, return_code OUT number, return_message out varchar2)
AS

i number;

BEGIN
   return_code := 0;
   execute immediate v_sql;
   i := sql%rowcount;

   IF (i<1)
     THEN return_code := 1;
   END IF;

EXCEPTION  
   WHEN OTHERS THEN
   return_message := SQLERRM;
   return_code := SQLCODE;
END;