HOWTO: Get and Use a Handle to a Directory

ID: Q105306

The information in this article applies to:

Microsoft Win32 Application Programming Interface (API) included with: - Microsoft Windows NT versions 3.1, 3.5, 3.51, 4.0

SUMMARY

CreateDirectory() can be used to open a new directory. An existing directory can be opened by calling CreateFile(). To open an existing directory with CreateFile(), it is necessary to specify the flag FILE_FLAG_BACKUP_SEMANTICS. The following code shows how this can be done:

   HANDLE hFile;

   hFile = CreateFile( "c:\\mstools",
              GENERIC_READ | GENERIC_WRITE,
              FILE_SHARE_READ | FILE_SHARE_WRITE,
              NULL,
              OPEN_EXISTING,
              FILE_FLAG_BACKUP_SEMANTICS,
              NULL
           );
   if( hFile == INVALID_HANDLE_VALUE )
      MessageBox( NULL, "CreateFile() failed", NULL, MB_OK );

The handle obtained can be used to obtain information about the directory or to set information about the directory. For example:

   BY_HANDLE_FILE_INFORMATION fiBuf;
   FILETIME ftBuf;
   SYSTEMTIME stBuf;
   char msg[40];

   GetFileInformationByHandle( hFile, &fiBuf );
   FileTimeToLocalFileTime( &fiBuf.ftLastWriteTime, &ftBuf );
   FileTimeToSystemTime( &ftBuf, &stBuf );
   wsprintf( msg, "Last write time is %d:%d  %d/%d/%d",
      stBuf.wHour,stBuf.wMinute,stBuf.wMonth,stBuf.wDay,stBuf.wYear );
   MessageBox( NULL, msg, NULL, MB_OK );

MORE INFORMATION

Opening directories with CreateFile is not supported on Windows 95.

This code does not work on Win32s, because MS-DOS does not support opening a directory. If you are looking for the creation time of a directory, use FindFirstFile(), because it works on all platforms.

Keywords          : kbAPI kbKernBase kbGrpKernBase 
Version           : winnt:3.1,3.5,3.51,4.0;
Platform          : winnt
Issue type        : kbhowto

Last Reviewed: November 28, 1997