minor
#define minor(x) ((int)((x)&0xffff00ff)) /* minor number */
struct minor {
# define minor(dev) ((int)((dev) & 0xff))
#define minor(x) ((int)((x)&0377))
#undef minor
#define minor(dev) (__minor(NEWDEV, dev))
#undef minor
#define minor(x) (minor_t)((x) & O_MAXMIN)
#define minor(x) (minor_t)((x) & O_MAXMIN)