| **Navigation:**  [[introduction.htm|Language Reference]] > 2 - Program Source Code Format > Compiler Directives >====== ONCE (prevent duplicate included data) ====== | [[omit specify source not to be compiled .htm|{{btn_prev_n.gif|Previous page}}]][[introduction.htm|{{btn_home_n.gif|Return to chapter overview}}]][[section specify source code section .htm|{{btn_next_n.gif|Next page}}]] | | || **ONCE** {{blk2blue.jpg|blk2blue.jpg}} The **ONCE** attribute precludes any data contained in the INCLUDE from being compiled more than once resulting in compile warnings or errors. **Example:** **INCLUDE('KEYCODES.CLW'),****ONCE** **See Also:** [[include compile code in another file .htm|INCLUDE]]