sock_fd = socket(AF_INET, SOCK_STREAM, 0)) //AF_INT:ipv4, SOCK_STREAM:tcp协议
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int sendto ( socket s , const void * msg, int len, unsigned int flags,
const struct sockaddr * to , int tolen ) ;
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int recvfrom(int s, void *buf, int len, unsigned int flags, struct sockaddr *from, int *fromlen);
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static void UDPClientTask(void)
{
	/* 服务器的地址信息 */
	struct sockaddr_in send_addr;
    char recvBuf[512];

    /* 连接Wifi */
    WifiConnect("TP-LINK_65A8","0987654321");

    /* 创建socket  */
	if((sock_fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
	{
		perror("create socket failed!\r\n");
		exit(1);
	}

    /* 初始化预连接的服务端地址 */
    send_addr.sin_family = AF_INET;
    send_addr.sin_port = htons(_PROT_);
    send_addr.sin_addr.s_addr = inet_addr("192.168.0.175");

    while (1)
    {
        bzero(recvBuf,sizeof(recvBuf));
        /* 发送数据到服务端 */
        sendto(sock_fd, send_data, strlen(send_data), 0, (struct sockaddr * )&send_addr, addr_length);

        /* 线程休眠一段时间 */
        sleep(10);

        /* 接收服务端返回的字符串*/
        recvfrom(sock_fd, recvBuf, sizeof(recvBuf), 0, (struct sockaddr * )&send_addr, &addr_length);
        printf("%s:%d=>%s\n", inet_ntoa(send_addr.sin_addr), ntohs(send_addr.sin_port), recvBuf);
  
    }

    /* 关闭这个 socket */
    closesocket(sock_fd);

}
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#"D1_iot_wifi_sta:wifi_sta",
#"D2_iot_wifi_sta_connect:wifi_sta_connect",         
"D3_iot_udp_client:udp_client",
#"D4_iot_tcp_server:tcp_server",
#"D5_iot_mqtt:iot_mqtt",        
#"D6_iot_cloud_oc:oc_mqtt",
#"D7_iot_cloud_onenet:onenet_mqtt",
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192.168.0.175:8888=>Hello! BearPi-HM_nano UDP Client!
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