Где определить переменные ?

bool __fastcall MyThread1::StartDataRead(BYTE BufferData1[256], DWORD BytesLength1, DWORD BytesRead1)
{
  OVERLAPPED ReadOL;
  DWORD WFSO;
  //-------------------------------------------------------------------------
  memset(&ReadOL, 0, sizeof(ReadOL));
  ReadOL.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
  if(ReadOL.hEvent == NULL)
  {
    Form1->Memo1->Lines->Add("Îøèáêà CreateEvent");
    CloseHandle(HidHandle);
    CloseHandle(ReadOL.hEvent);
    return 0;
  }
  //-------------------------------------------------------------------------
  if(!ReadFile(HidHandle, BufferData1, BytesLength1, &BytesRead1, &ReadOL))
  {
    Form1->Memo1->Lines->Add("Îøèáêà àñèíõðîííîãî ÷òåíèÿ ReadFile");
    CloseHandle(HidHandle);
    CloseHandle(ReadOL.hEvent);
    return 0;
  }
  //-------------------------------------------------------------------------
  WFSO = WaitForSingleObject(ReadOL.hEvent, INFINITE);
  if(WFSO == WAIT_OBJECT_0)
  {
    if(!GetOverlappedResult(HidHandle, &ReadOL, 0, 1))
    {
      Form1->Memo1->Lines->Add("Ðåçóëüòàò ÷òåíèÿ íå ïîëó÷åí GetOverlappedResult");
      CloseHandle(HidHandle);
      CloseHandle(ReadOL.hEvent);
      return 0;
    }
    else
    {
      Form1->Memo1->Lines->Add("Ðåçóëüòàò ÷òåíèÿ ïîëó÷åí GetOverlappedResult");
    }
  }
  else
  {
    Form1->Memo1->Lines->Add("ÎØÈÁÊÀ WaitForSingleObject");
    CloseHandle(HidHandle);
    CloseHandle(ReadOL.hEvent);
    return 0;
  }
  //-------------------------------------------------------------------------
  CloseHandle(ReadOL.hEvent);
 
  return 1;
}