private static extern void UploadImg(structs.RawImg img, out structs.UploadImgResult result);
private static extern void Search(structs.ImgQuery query, out structs.SearchResult result);
private static extern void Search1(structs.ImgQuery query);
private static extern void IndexDirectory([MarshalAs(UnmanagedType.LPWStr)]string dirPath, out structs.IndexDirectoryResult result);