static extern int ioctl32(int fd, int request, ref Crypt crypt);
static extern int ioctl64(int fd, ulong request, ref Crypt crypt);
internal static int CryptOp(ref Crypt crypt) { if (IntPtr.Size == 4) return ioctl32 (fildes, (int) CIOCCRYPT, ref crypt); else return ioctl64 (fildes, CIOCCRYPT, ref crypt); }