struct addrinfo hints, *res;
// 首先,用 getaddrinfo() 載入位址結構:
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC; // use IPv4 or IPv6, whichever
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE; // fill in my IP for me
getaddrinfo(NULL, "3490", &hints, &res);
sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
// 將 socket bind 到我們傳遞給 getaddrinfo() 的 port:
bind(sockfd, res->ai_addr, res->ai_addrlen);