for(;;){

         socklen_t len = sizeof(client_address);

         connfd = accept(listenfd, (struct sockaddr *)&client_address, &len);

         if(connfd < ){

             printf("accept error: %s\n", strerror(errno));

         }

         printf("server get connection from %s\n", inet_ntop(AF_INET, &client_address.sin_addr, buff, sizeof(buff)));

         if((n = read(listenfd, message, )) == -){

             printf("read error: %s\n", strerror(errno));

             exit();

         }

         message[n] = '\0';

         printf("receive the message of client: %s\n", message);

         close(connfd);

     }

        if((n = read(connfd, message, )) == -){ 

int accept(int sockfd, struct sockaddr *cliaddr, socklen_t *addrlen);

int read(int handle, void *buf, int nbyte);