int (*open) (int num);
void (*close) (int handle);
int (*transfer) (WD_TRANSFER *tr, int fd, unsigned int request, int ppbase, int ecpbase, int num);
int (*open) (int num);
void (*close) (int handle);
int (*transfer) (WD_TRANSFER *tr, int fd, unsigned int request, int ppbase, int ecpbase, int num);