如何在检测服务器断开情况下重新连接程序？

回复【楼主位】yangzi6000:
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你参考的是我发的那个例程么？

楼主在吗？connect_net 这个是哪个函数的返回值？
你用哪个函数判断网络连接还在不在的？

楼主你移植到mini开发板的吗？能不能指点下

关于客户端重连的问题能发个程序共享下不？谢谢！

楼主，请问下，我也是用LWIP，发现发送一段时间就发送不出去，已经调用了tcp_write,但是发送不出去，然后我就在这里close_pcb，然后重连，再发送一段时间，重复几次后就再也连接不上服务器了！

static err_t tcp_echoclient_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err)
{
  struct echoclient *es;
  err_t ret_err;
  
  LWIP_ASSERT("arg != NULL",arg != NULL);
  
  es = (struct echoclient *)arg;
  
  /* if we receive an empty tcp frame from server => close connection */
if (p == NULL)
  {
    /* remote host closed connection */
    es->state = ES_CLOSING;
    if(es->p_tx == NULL)
    {
       /* we're done sending, close connection */
       tcp_echoclient_connection_close(tpcb, es);
    }
    else
    {   
      /* send remaining data*/
      tcp_echoclient_send(tpcb, es);
    }
    ret_err = ERR_OK;
  }   
  /* else : a non empty frame was received from echo server but for some reason err != ERR_OK */
  else if(err != ERR_OK)
  {
    /* free received pbuf*/
    if (p != NULL)
    {
      pbuf_free(p);
    }
    ret_err = err;
  }
  else if(es->state == ES_CONNECTED)
  {
    /* increment message count */
    message_count++;
         
    /* Acknowledge data reception */
    tcp_recved(tpcb, p->tot_len);  
   
    pbuf_free(p);
    tcp_echoclient_connection_close(tpcb, es);
    ret_err = ERR_OK;
  }
  /* data received when connection already closed */
  else
  {
    /* Acknowledge data reception */
    tcp_recved(tpcb, p->tot_len);
   
    /* free pbuf and do nothing */
    pbuf_free(p);
    ret_err = ERR_OK;
  }
  return ret_err;
}
标色的就是检测到连接断开。

static err_t tcp_echoclient_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err)
{
  struct echoclient *es;
  err_t ret_err;
  
  LWIP_ASSERT("arg != NULL",arg != NULL);
  
  es = (struct echoclient *)arg;
  
  /* if we receive an empty tcp frame from server => close connection */
  if (p == NULL)
  {
    /* remote host closed connection */
    es->state = ES_CLOSING;
    if(es->p_tx == NULL)
    {
       /* we're done sending, close connection */
       tcp_echoclient_connection_close(tpcb, es);
    }
    else
    {   
      /* send remaining data*/
      tcp_echoclient_send(tpcb, es);
    }
    ret_err = ERR_OK;
  }   
  /* else : a non empty frame was received from echo server but for some reason err != ERR_OK */
  else if(err != ERR_OK)
  {
    /* free received pbuf*/
    if (p != NULL)
    {
      pbuf_free(p);
    }
    ret_err = err;
  }
  else if(es->state == ES_CONNECTED)
  {
    /* increment message count */
    message_count++;
         
    /* Acknowledge data reception */
    tcp_recved(tpcb, p->tot_len);  
   
    pbuf_free(p);
    tcp_echoclient_connection_close(tpcb, es);
    ret_err = ERR_OK;
  }
  /* data received when connection already closed */
  else
  {
    /* Acknowledge data reception */
    tcp_recved(tpcb, p->tot_len);
   
    /* free pbuf and do nothing */
    pbuf_free(p);
    ret_err = ERR_OK;
  }
  return ret_err;
}
上面标错地方了。。

我检测到断开连接，前面几次可以重连上，但是之后就重连不上了！

我也是多少次断开网线后，不能重新连接上PC的服务器端。