Windows platform libraw bring in dng sdk has no effect or can't open dng file

I compiled dngsdk under Windows as described in dngsdk.txt and tested dng_validate and it works fine
But when I bring the entire dng sdk header file and static library into libraw to compile and set the `USE_DNGSDK ` preprocessing macro, it compiles fine but when I open the dng file with libraw, it tells me that it can't be opened for unsupported file formats. So I would like to ask if I am missing something?