anchor.diff:    
   (defcunion can_address
     (tp (:struct TP)))
  -  
  +
  +;; struct sockaddr_can {
  +;;     sa_family_t can_family;
  +;;     int         can_ifindex;
  +;;     union {
  +;; 	/* transport protocol class address info (e.g. ISOTP) */
  +;; 	struct { canid_t rx_id, tx_id; } tp;
  +
  +;; 	/* reserved for future CAN protocols address information */
  +;;     } can_addr;
  +;; };
  +
   (defcstruct sockaddr-can
     (can_family sa_family_t)
     (can_ifindex :int)
  
positive.code:   (option :int32)
    (val :pointer)
    (vlen :int32))
  
  
  
  ;; int fcntl(int fd, int cmd, ... /* arg */ );
  (defcfun (%fcntl "fcntl") :int32
  
negative.code: ;; void freeifaddrs(struct ifaddrs *ifa);
  (defcfun (%freeifaddrs "freeifaddrs") :void
    (ifaddrs :pointer))
          
  ;; struct ifreq
  ;;   {
  