CREATE OR REPLACE PROCEDURE proc3  
IS  
BEGIN  
   DBMS_OUTPUT.put_line ('calling proc2');  
   proc2;  
EXCEPTION  
   WHEN OTHERS  
   THEN  
      DBMS_OUTPUT.put_line ('Error backtrace at top level:');  
      DBMS_OUTPUT.put_line (DBMS_UTILITY.format_error_backtrace);  
END;