Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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Display-driver initialization occurs when Windows creates the
original-device context for the Windows desktop. To create the device
context, Windows loads the display driver and calls the driver's
initialization routine.
 
Although the initialization routine can carry out any task, many drivers do
the following:
 
♦  Determine whether 386 enhanced-mode Windows screen switching is required
 
♦  Initialize display hardware
 
♦  Determine whether mouse trails support is required
 
♦  Install any modal functions
 
Modal functions have implementations based on CPU type, hardware
configuration, or Windows mode of operation. For example, the ExtTextOut
function for a 80386 CPU may use 32-bit registers but the same function for
a 80826 uses 16-bit registers. In another example, a driver may install
cursor functions for a hardware cursor in one hardware configuration and
install functions for a software cursor in another.
 
Although a display driver may carry out some hardware initialization in its
initialization routine, it should wait until GDI calls the driver's Enable
function for a second time before fully initializing the video hardware.
 
The initialization routine returns to Windows if the initialization was
successful. Otherwise, it returns zero and Windows immediately terminates.
 
 
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