DDK_INC_PATH
Use the DDK_INC_PATH macro to specify the path to the Windows Driver Kit (WDK) header files.
In the WDK, the default value is:
WDKROOT\inc\ddk
For this default value, WDKROOT is the root installation directory of the WDK.
Send comments about this topic to Microsoft
Build date: 5/3/2011