이 프로그램이 non-blocking으로 작동이 되는지 궁금합니다.

int oldopts;
oldopts = fcntl(sockfd, F_GETFL, 0);
fcntl(sockfd, F_SETFL, oldopts | O_NONBLOCK);

 
 int     i;
    int     opt = 1;
    long    sockArgs;
    int     sock;
    struct sockaddr_in serv_addr;
    struct epoll_event  ev;
 
    memset ((char *) &serv_addr, 0x00, sizeof(serv_addr));
    serv_addr.sin_family        = AF_INET;
    serv_addr.sin_addr.s_addr   = htonl(INADDR_ANY);
    serv_addr.sin_port          = (unsigned short)htons (port);
    /* open tcp socket */
    if ((sock = socket (AF_INET, SOCK_STREAM, 0)) < 0)
         return -1;
 
    setsockopt( sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(int));
 
    if (bind(sock, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
          return -1;
 
    if (listen(sock, 1) < 0)
        return -1;
    sockArgs = fcntl(sock, F_GETFL);
    fcntl(sock, F_SETFL, sockArgs | FNDELAY);
 
    ev.events = EPOLLIN;
    ev.data.fd = sock;
    epoll_ctl(epollFd, EPOLL_CTL_ADD, sock, &ev);

 sockArgs = fcntl(sock, F_GETFL);
 fcntl(sock, F_SETFL, sockArgs | FNDELAY);