19     printf("Server is exiting...\n");  in signal_handler()
32     printf("TCP Server is running...\n");  in tcp_server()
34     printf("socket() ok, server_sockfd=%d\n", server_sockfd);  in tcp_server()
46     printf("TCP Server is listening...\n");  in tcp_server()
53     printf("listen() ok\n");  in tcp_server()
66     printf("Connection established.\n");  in tcp_server()
69         printf("Create connection failed, code=%d\n", conn);  in tcp_server()
79             printf("Receive data failed! len=%d\n", len);  in tcp_server()
87         printf("Received: %s\n", buffer);  in tcp_server()
96     printf("UDP Server is running...\n");  in udp_server()
98     printf("socket() ok, server_sockfd=%d\n", server_sockfd);  in udp_server()
110     printf("UDP Server is listening...\n");  in udp_server()
122             printf("Receive data failed! len=%d", len);  in udp_server()
130         printf("Received: %s", buffer);  in udp_server()
132         printf("Send: %s", buffer);  in udp_server()
140     printf("Client is running...\n");  in tcp_client()
147     printf("to connect\n");  in tcp_client()
153     printf("connected to server\n");  in tcp_client()
180             printf("recv error, retval=%d\n", x);  in tcp_client()
212     printf("to send logo\n");  in udp_client()
214     printf("send logo ok\n");  in udp_client()
219         printf("Please enter a string to send to server: \n");  in udp_client()
223         printf("to send: %d\n", len);  in udp_client()
229         printf("Receive from server: %s\n", buffer);  in udp_client()