Using FND_REQUEST.ADD_LAYOUT to pick template without Hardcoding And

Using $$PLSQL_LINE and $$PLSQL_UNIT to find out exact line of Error and Program Unit

Sample Code to use $$PLSQL_LINE and $$PLSQL_UNIT for debugging.
It will provide the exact line of error and the Program Unit.

CREATE OR REPLACE PROCEDURE XX_TEST_DEBUG AS

  v_debug_line PLS_INTEGER := $$PLSQL_LINE;

  v_debug_proc VARCHAR2(240)  := $$PLSQL_UNIT;

  v_po_num VARCHAR2(240);

BEGIN

SELECT SEGMENT1  INTO v_po_num FROM PO_HEADERS_ALL;

EXCEPTION WHEN OTHERS THEN

DBMS_OUTPUT.PUT_LINE(SQLERRM || v_debug_line ||'-'|| v_debug_proc);

END;