int set_nonblocking(int fd);
int get_max_fds(void);
int lookup_ip(const char *host_name, struct in_addr *address);
+int lookup_ipv6(const char *host_name, struct in6_addr *address);
int get_socket_error(int sock);
int check_connection_completion(int fd);
int drain_rcvbuf(int fd);