Function tcpclient

examples/network/tcpclient.c:45–185

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

* @brief  This function is for creating a tcp client on RT-Thread
*/
static void tcpclient(void *arg)
{
    int ret;
    char *recv_data;
    int bytes_received;
    int sock = -1;
    struct hostent *host = RT_NULL;
    struct sockaddr_in server_addr;

    struct timeval timeout;
    fd_set readset;
    /* 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 = gethostbyname(url);
    if (host == RT_NULL)
    {
        LOG_E("Get host by name failed!");
        return;
    }
    /* Allocate space for recv_data */
    /* 分配用于存放接收数据的缓冲 */
    recv_data = rt_malloc(BUFSZ);
    if (recv_data == RT_NULL)
    {
        LOG_E("No memory");
        return;
    }
    /* Create a socket and set it to SOCK_STREAM(TCP) */
    /* 创建一个socket，类型是SOCKET_STREAM，TCP类型 */
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    {
        /* Failed on creating socket */
        /* 创建socket失败 */
        LOG_E("Create socket error");
        goto __exit;
    }
    /* 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));
    /* Connect to server */
    /* 连接到服务端 */
    if (connect(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1)
    {
        /* Failed on connecting to server */
        /* 连接失败 */
        LOG_E("Connect fail!");
        goto __exit;
    }

    started = 1;
    is_running = 1;

    timeout.tv_sec = 3;
    timeout.tv_usec = 0;