ReadFile函数卡住

你在打开文件时用了FILE_FLAG_OVERLAPPED，但是ReadFile中 lpOverlapped传的是NULL。
把FILE_FLAG_OVERLAPPED改成FILE_ATTRIBUTE_NORMAL试试。 
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 打开文件时不用FILE_FLAG_OVERLAPPED，ReadFile的最后一个参数就是NULL。
如果用了FILE_FLAG_OVERLAPPED，则ReadFile的最后一个参数必须是一个OVERLAPPED结构。下面只是一个最简单的例子，一般不是多线程没有必要：
OVERLAPPED overlap;
memset(&overlap, 0, sizeof(overlap));
  rc = ReadFile(m_CID_Handle,buf,128,&dwLength  &overlap);
  if (rc)
  {
         //the data was read successfully
  }
  else
  {
         if (GetLastError() == ERROR_IO_PENDING)
         {
                WaitForSingleObject(m_CID_Handle,INFINITE);
                rc = GetOverlappedResult(m_CID_Handle, &overlap, &dwLength,  FALSE);
         }
         else
         {
         }
  }