UDP Tx partial fail when using Lwip within uC/OS

[Altera_Forum]

hi all! 

 I was trying to send a UDP packet using conn_send(). However, I find that when I use netbuf_ref() to send data which the ptr points to, what I got in the reciever side was not the data ptr point to. But is was OK if I&#39;m using netbuf_alloc() to send some immediate data.  Another thing that I can&#39;t understand is whichever buffer or data structure the ptr points to, when using netbuf_ref(), the data sent on the physical wire is always the same!  Here&#39;s my code:  void udp_task() { struct netconn *conn; struct netbuf* buf; struct ip_addr udpDestIpAddr,udpLocalIpAddr; u8_t test[10]; int i; u8_t *data; void *ptr;  for(i=0;i<10;i++){  test=i;  } ptr = test;  conn = netconn_new(netconn_udp); ip4_addr(&udpdestipaddr, 10, 1, 1, 15); ip4_addr(&udplocalipaddr, 10, 1,1, 19);  printf("udp_init\n"); netconn_bind(conn,&udplocalipaddr,38); netconn_connect(conn,&udpdestipaddr,10);  while(1) { buf = netbuf_new(); data = netbuf_alloc(buf,10); for(i=0;i<10;i++) data=i; netconn_send(conn, buf); //""this command function just the way it is, and I recieve exactly what I sent ""   netbuf_ref(buf,&test[0],10); netconn_send(conn, buf); //""here is where everything goes wrong, I recieved the wrong data""  netbuf_ref(buf,&test[0]+10,10); netconn_send(conn, buf); /*""I recieved exactly the same fault data just like above, it seems the pointer has *no effect of determining which data should be sent"" */  OSTimeDlyHMSM(0, 0, 3, 0); printf("udp sent ");  netbuf_delete(buf); } }  Thanks in advance!