Function tcp_poll

components/net/lwip/lwip-2.1.2/src/core/tcp.c:2104–2118

* @ingroup tcp_raw * Specifies the polling interval and the callback function that should * be called to poll the application. The interval is specified in * number of TCP coarse grained timer shots, which typically occurs * twice a second. An interval of 10 means that the application would * be polled every 5 seconds. * * When a connection is idle (i.e., no data is either transmitted or

 * again when the connection has been idle for a while.
 */
void
tcp_poll(struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval)
{
  LWIP_ASSERT_CORE_LOCKED();

  LWIP_ERROR("tcp_poll: invalid pcb", pcb != NULL, return);
  LWIP_ASSERT("invalid socket state for poll", pcb->state != LISTEN);

#if LWIP_CALLBACK_API
  pcb->poll = poll;
#else /* LWIP_CALLBACK_API */
  LWIP_UNUSED_ARG(poll);
#endif /* LWIP_CALLBACK_API */
  pcb->pollinterval = interval;
}

/**
 * Purges a TCP PCB. Removes any buffered data and frees the buffer memory