例題: TCP接続するクライアント

struct addrinfo hints, *res, *res0;
int error, s;

memset(&hints, 0, sizeof(hints));
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
error = getaddrinfo("www.kame.net", "http", &hints, &res0);
if (error)
    errx(1, "%s", gai_strerror(error));
/* res0 holds addrinfo chain */
s = -1;
for (res = res0; res; res = res->ai_next) {
    s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
    if (s < 0)
        continue;
    error = connect(s, res->ai_addr, res->ai_addrlen);
    if (error) {
        close(s);
        s = -1;
        continue;
    }
    break;
}
freeaddrinfo(res0);
if (s < 0)
    die();