ms-help://MS.MSDNQTR.2003FEB.1041/fileio/base/writefile.htm
＞Windows Me/98/95: For operations on files, disks, pipes, or mailslots,
＞this parameter must be NULL; a pointer to an OVERLAPPED structure causes
＞the call to fail. However, the function supports overlapped I/O on serial and parallel ports.