Function udpclient

examples/network/udpclient.c:36–95

* @brief This function is for creating a udp client on RT-Thread */

* @brief  This function is for creating a udp client on RT-Thread
*/
static void udpclient(void *arg)
{
    int sock;
    struct hostent *host;
    struct sockaddr_in server_addr;
    /* Get host address by parameter URL (domain name resolution if input domain) */
    /* 通过函数入口参数url获得host地址（如果是域名，会做域名解析） */
    host = (struct hostent *) gethostbyname(url);
    if (host == RT_NULL)
    {
        LOG_E("Get host by name failed!");
        return;
    }
    /* Create a socket and set it to SOCK_DGRAM(UDP) */
    /* 创建一个socket，类型是SOCK_DGRAM，UDP类型 */
    if ((sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
    {
        /* Failed on creating socket */
        LOG_E("Create socket error");
        return;
    }
    /* Initialize server side address */
    /* 初始化预连接的服务端地址 */
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(port);
    server_addr.sin_addr = *((struct in_addr *)host->h_addr);
    rt_memset(&(server_addr.sin_zero), 0, sizeof(server_addr.sin_zero));

    started = 1;
    is_running = 1;
    /* The total sending number(count)  */
    /* 总计发送count次数据 */
    while (count && is_running)
    {
        /* Send message to server side */
        /* 发送数据到服务远端 */
        sendto(sock, send_data, rt_strlen(send_data), 0,
               (struct sockaddr *)&server_addr, sizeof(struct sockaddr));
        /* Thread sleep for 1 second */
        /* 线程休眠一段时间 */
        rt_thread_mdelay(1000);
        /* count decrease 1 */
        /* 计数值减一 */
        count --;
    }

    if (count == 0)
    {
        LOG_I("UDP client send data finished!");
    }
    /* Close the socket */
    /* 关闭这个socket */
    if (sock >= 0)
    {
        closesocket(sock);
        sock = -1;
    }
    started = 0;