This function flushes the output queue of a connection. Messages in the output queue of a connection are sent by the MX manager, in a scheduled manner. If an application wants to close a connection it uses this function to send all messages still pending.  Notice that an application that works in an asynchronous mode uses MXPutMessage which only puts the message in the output queue. The messages in the output are sent by MXDispatchEvents 

  ...

if (STORE)
{
  char FileType = 't';

  FileCom = MXOpenFile (&mx, "FTP.sto", "w", IOPROTO_STORE, 'D', 63);
  if (!FileCom) return 0; 

  pmessage = MXPutMessage (FileCom, FTP_SYS, "Command");
  MXSetValue (pmessage, "Value", 1, "USER");
  MXSetValue (pmessage, "Par", 1, "bartocci");

  pmessage = MXPutMessage (FileCom, FTP_SYS, "Command");
  MXSetValue (pmessage, "Value", 1, "PASS");
  MXSetValue (pmessage, "Par", 1, "pass");

  pmessage = MXPutMessage (FileCom, FTP_SYS, "dir");
  MXSetValue (pmessage, "Value", 1, "LIST");
  MXSetValue (pmessage, "Par", 1, "");

  pmessage = MXPutMessage (FileCom, FTP_SYS, "get") ;
  MXSetValue(pmessage, "FileName", 1, "t.c") ;
  MXSetValue(pmessage, "DestName", 1, "t.c") ;
  MXSetValue(pmessage, "FileType", 1, &FileType) ;
  MXSetValue(pmessage, "Command", 1, "get") ;

  MXFlushCom (&mx, FileCom);

  MXCloseCom (&mx, FileCom);

  FTPCom = MXOpenTCP (&mx, "194.214.100.8", 21, IPPROTO_FTP, NULL, NULL, TRUE);
  if (!FTPCom) return 0;

  MXAddComCallBack (&mx, FTPCom, FTP_SYS, "Command", MXONSEND, Command, NULL);
  MXAddComCallBack (&mx, FTPCom, FTP_SYS, "Command_Reply", MXONRECV, CommandReply, NULL);
  MXAddComCallBack (&mx, FTPCom, FTP_SYS, "dir_reply", MXONRECV, DirReply, NULL);
  MXAddComCallBack (&mx, FTPCom, FTP_SYS, "get_reply", MXONRECV, GetReply, NULL);

  FileCom = MXOpenFile (&mx, "FTP.sto", "r", IOPROTO_STORE, 'D', 63);
  if (!FileCom) return 0;

  while (pmessage = MXRecv (&mx, FileCom))
  {
    MXPutThisMessage (FTPCom, pmessage);   
  }
  MXCloseCom (&mx, FileCom);
}

  ...

  MXDispatchEvents (&mx, 0);
  MXEnd (&mx);
  return 0;