The DDSURFACEDESC2 structure is defined as :-

struct DDSURFACEDESC2 {
DWORD dwSize;
DWORD dwFlags;
DWORD dwHeight;
DWORD dwWidth;
union
{
LONG lPitch;
DWORD dwLinearSize;
} DUMMYUNIONNAMEN(1);
DWORD dwBackBufferCount;
union
{
DWORD dwMipMapCount;
DWORD dwRefreshRate;
} DUMMYUNIONNAMEN(2);
DWORD dwAlphaBitDepth;
DWORD dwReserved;
LPDIRECTDRAWSURFACE lpSurface;
union
{
DDCOLORKEY ddckCKDestOverlay;
DWORD dwEmptyFaceColor;
} DUMMYUNIONNAMEN(3);
DDCOLORKEY ddckCKDestBlt;
DDCOLORKEY ddckCKSrcOverlay;
DDCOLORKEY ddckCKSrcBlt;
DDPIXELFORMAT ddpfPixelFormat;
DDSCAPS2 ddsCaps;
DWORD dwTextureStage;
};