NAME
        ModeNotAvailable -- check to see if a DisplayID isn't available. (V36)

   SYNOPSIS
        error =  ModeNotAvailable( modeID )
        d0                         d0

        ULONG   ModeNotAvailable( ULONG);

   FUNCTION
        returns an error code, indicating why this modeID is not available,
        or NULL if there is no reason known why this mode should not be there.

   INPUTS
        modeID -- a 32 bit DisplayInfoRecord identifier.

   RESULT
        error -- a general indication of why this modeID is not available,
                 or NULL if there is no reason why it shouldn't be available.

   NOTE
        ULONG return values from this function are a proper superset of the
        DisplayInfo.NotAvailable field (defined in graphics/displayinfo.h).

        ModeNotAvailable() will return INVALID_ID when given a non-existant
        moe ID.

   BUGS

   SEE ALSO
        graphics/displayinfo.h, getvpmodeid()