dvd_struct
struct dvd_struct *dvdstruct;
dvdstruct = (struct dvd_struct *)addr;
struct dvd_struct *dvdstruct);
cdreaddvdstructure(struct cam_periph *periph, struct dvd_struct *dvdstruct)
acd_read_structure(device_t dev, struct dvd_struct *s)
error = acd_read_structure(dev, (struct dvd_struct *)ap->a_data);
static int acd_read_structure(device_t, struct dvd_struct *);
#define DVDIOCREADSTRUCTURE _IOWR('c', 202, struct dvd_struct)