How to port applications to IPv6

struct sockaddr_in6 {
  sa_family_t sin6_family; /* AF_INET6 */
  in_port_t sin6_port; /* Transport layer port # */
  uint32_t sin6_flowinfo; /* IPv6 flow information */
  struct in6_addr sin6_addr; /* IPv6 address */
  uint32_t sin6_scope_id; /* IPv6 scope-id */
};

Eva M. Castro has done a wonferful job with her porting  to IPv6 article.

Read and Enjoy.