Overlay component instrumentation can be difficult to debug because of its transitory nature. To facilitate this kind of debugging, you can use a debug option when running the service layer.

Before you use this option, you must stop the service layer, if it's already running. If you start the service layer automatically when your system starts, do the following:

• Comment out the RUN= line in your CONFIG.SYS file that starts the DMISL.EXE program.

• Restart your system.

To start the service layer with the debug option, enter the following command from an OS/2 command prompt:

DMISL DEBUG

If the subdirectory containing the service layer executable file is not in your PATH statement, enter the appropriate drive and path as part of the command.

When the service layer is loaded, a debug address is displayed. When you set a breakpoint at this address, execution stops just before the DmiCiInvoke() function call is issued. At this point the overlay component DLL is already loaded, and you can specify breakpoints in the instrumentation wherever you need them.