Poll()是起什么用的？

FatTony

BOOL ReadDevice(IDirectInputDevice8 *pDIDevice,                               void *DataBuffer, long BufferSize)
{
  HRESULT hr;

  while(1) {
    // Poll device
    g_pDIDevice-&gtoll();

    // Read in state
    if(SUCCEEDED(hr = g_pDIDevice->GetDeviceState(BufferSize,(LPVOID)DataBuffer)))
      break;

    // Return on an unknown error  
    if(hr != DIERR_INPUTLOST && hr != DIERR_NOTACQUIRED)
      return FALSE;

    // Reacquire and try again
    if(FAILED(g_pDIDevice->Acquire()))
      return FALSE;
  }

  // Return a success
  return TRUE;
}
如题，谢谢了！