Initializing the Pen Driver

After installing the virtual pen driver, Windows next reads the pen installable driver component from the installable driver line of the SYSTEM.INI file. It loads the specified pen driver by calling the OpenDriver function, using the PENC.DRV filename. When the driver successfully loads, Windows sends it three messages in the following order: DRV_LOAD, DRV_ENABLE, and DRV_OPEN. The PENC.DRV driver handles these messages in its DriverProc function.