sbd_ioctl
int (*sbd_ioctl) (dev_t, int, intptr_t, int, char *);
sbd_ioctl = (int (*) (dev_t, int, intptr_t, int, char *))
if (sbd_ioctl)
rv = (*sbd_ioctl) (dev, cmd, arg, mode, &event);
extern int sbd_ioctl(dev_t dev, int cmd, intptr_t arg, int mode,