#include <rtl.h>

BOOL tcp_check_send (
    U8 socket );    /* TCP socket to check whether it can send data. */

The tcp_check_send function determines if the TCP socket can send data. It does this by checking whether the TCP connection has been established and whether the socket has received an acknowledgement from the remote machine for the previously sent data. The argument socket specifies the handle of the socket to check.

The tcp_check_send function is in the RL-TCPnet library. The prototype is defined in rtl.h.

The tcp_check_send function returns __TRUE if the socket is ready to send data. Otherwise, the function returns __FALSE.

tcp_get_state

#include <rtl.h>

void send_data () {
  U8 remip[4] = {192,168,1,100};
  U8 *sendbuf;

  switch (tcp_get_state (socket_tcp)) {
    case TCP_STATE_FREE:
    case TCP_STATE_CLOSED:
      /* Connection idle, send Connect Request. */
      tcp_connect (socket_tcp, Rem_IP, 1001, 0);
      break;
    case TCP_STATE_CONNECT:
      /* We are connected, send command to remote peer. */
      if (tcp_check_send (socket_tcp)) {
        /* OK, socket is ready to send data. */
        sendbuf = tcp_get_buf (2);
        sendbuf[0] = BLINKLED;
        sendbuf[1] = p2;
        tcp_send (socket_tcp, sendbuf, SENDLEN);
      }
      break;
  }
}