int main()
{
    int sockfd, connfd;
    struct sockaddr_in servaddr;
    socklen_t len;
    struct linger linger;
    
    if (bind(sockfd, (struct sockaddr*)&servaddr, sizeof servaddr) < 0)
        err_sys("bind error");
    if (listen(sockfd, LISTENQ) < 0)
        err_sys("listen error");
    linger.l_onoff = 1;
    linger.l_linger = 0;
    if (setsockopt(sockfd, SOL_SOCKET, SO_LINGER, &linger, len) < 0)
        err_sys("error setlinger\n");
    connfd = accept(sockfd, (struct sockaddr*)&servaddr, &len);
    close(connfd);
    close(sockfd);
    return 0;
}