typedef HRESULT (WINAPI* LPD3DVALIDATECALLBACK)
(LPVOID lpUserArg, DWORD dwOffset);
Application-defined callback function supplied when an application calls the IDirect3DExecuteBuffer::Validate method. This method is a debugging routine that checks the execute buffer and returns an offset into the buffer when any errors are encountered.
lpUserArg
Address of application-defined data passed to this callback function.
dwOffset
Offset into the execute buffer at which the system found an error.
When determining the order in which to call callback functions, the system searches the objects highest in the hierarchy first, and then calls their callback functions in the order in which they were created.