socklen_t alen = sizeof(a);
struct sockaddr_in * sinp = (struct sockaddr_in *)&a;
struct sockaddr_in6 * sin6p = (struct sockaddr_in6 *)&a;
socklen_t alen = sizeof(a);
struct sockaddr_in * sinp = (struct sockaddr_in *)&a;
struct sockaddr_in6 * sin6p = (struct sockaddr_in6 *)&a;