IPv4 datagramIPv6 datagram AF_INET SOCK_STREAM sockaddr_in AF_INET SOCK_DGRAM sockaddr_in AF_INET6 SOCK_DGRAM sockaddr_in6 AF_INET6 SOCK_DGRAM sockaddr_in6 TCP IPv4 IPv6 UDP IPv4 sockets IPv6 sockets Address for connect or sendto IPv6 IPv4 IPv4 mapped IPv6