/* print port number */
switch( results->ai_family ) {
    case AF_INET: {
        struct sockaddr_in *v4 = (struct sockaddr_in*)results->ai_addr;
        printf("    port          : %hu\n", ntohs(v4->sin_port) );
        break;
    }
    case AF_INET6: {
        struct sockaddr_in6 *v6 = (struct sockaddr_in6*)results->ai_addr;
        printf("    port          : %hu\n", ntohs(v6->sin6_port) );
        break;
    }
}