[This is preliminary documentation and subject to change.]
The LPDDIPARAMS type defines a variable that contains the address of one of the DDI parameter structures. The DDI parameters structures are included in the winddi.h header file, which defines LPDDIPARAMS as follows:
typedef LPVOID LPDDIPARAMS;
This data type is used with CallNextDDI function and the DDIHookProc callback function.