WSAEvent2

 DWORD WINAPI WorkerThread(LPVOID lpParam)
{
 int ret, index;
 WSANETWORKEVENTS NetworkEvents;
 char szMessage[MSGSIZE];
 while (TRUE)
 {
  ret = WSAWaitForMultipleEvents(g_iTotalConn, g_CliEventArr, FALSE, 1000, FALSE);
  if (ret == WSA_WAIT_FAILED || ret == WSA_WAIT_TIMEOUT)
  {
   continue;
  }
  index = ret - WSA_WAIT_EVENT_0;
  WSAEnumNetworkEvents(g_CliSocketArr[index], g_CliEventArr[index], &NetworkEvents);
  if (NetworkEvents.lNetworkEvents & FD_READ)
  {
   // Receive message from client
   ret = recv(g_CliSocketArr[index], szMessage, MSGSIZE, 0);
   if (ret == 0 || (ret == SOCKET_ERROR && WSAGetLastError() == WSAECONNRESET))
   {
    Cleanup(index);
   }
   else
   {
    szMessage[ret] = '\0';
    send(g_CliSocketArr[index], szMessage, strlen(szMessage), 0);
   }
  }
  if (NetworkEvents.lNetworkEvents & FD_CLOSE)
  {
   Cleanup(index);
  }
 }
 return 0;
}
void Cleanup(int index)
{
 closesocket(g_CliSocketArr[index]);
 WSACloseEvent(g_CliEventArr[index]);
 if (index < g_iTotalConn-1)
 {
  g_CliSocketArr[index] = g_CliSocketArr[g_iTotalConn-1];
  g_CliEventArr[index] = g_CliEventArr[g_iTotalConn-1];
 }
 g_iTotalConn--;
}