ReadFile( __in HANDLE hFile, 
          __out_bcount_part(nNumberOfBytesToRead, *lpNumberOfBytesRead) LPVOID lpBuffer,
          __in DWORD nNumberOfBytesToRead, 
          __out_opt LPDWORD lpNumberOfBytesRead, 
          __inout_opt LPOVERLAPPED lpOverlapped );
这个函数中的nNumberOfBytesToRead的范围有限制吗?我在编程中怎么发现它<=8呢?