> -----Original Message----- > From: hans.somers@nl.abnamro.com [mailto:hans.somers@nl.abnamro.com] > > The filepath (drive + folderpath + filename) theoraticly > can take up to 32000 charaters if the filesystem in use is NTFS. > However, the way in wich Windows NT (4.0, 2000 and XP) access this > filesystem a maximum of 256 characters is in place. This isn't quite correct. If you RTFM, you find from the documentation on CreateFile: Windows NT/2000/XP: In the ANSI version of this function, the name is limited to MAX_PATH characters. To extend this limit to nearly 32,000 wide characters, call the Unicode version of the function and prepend "\\?\" to the path. For more information, see File Name Conventions. BTW, The Fine Manual can be found at http://msdn.microsoft.com/library/en-us/fileio/filesio_7wmd.asp?frame=tr ue Clicking on the link labeled 'File Name Conventions' gives: Process a path as a null-terminated string. The maximum length for a path, including a trailing backslash, is given by MAX_PATH. The Unicode versions of several functions permit paths that exceed the MAX_PATH length if the path has the "\\?\" prefix. The "\\?\" tells the function to turn off path parsing. However, each component in the path cannot be more than MAX_PATH characters long. Use the "\\?\" prefix with paths for local storage devices and the "\\?\UNC\" prefix with paths having the Universal Naming Convention (UNC) format. The "\\?\" is ignored as part of the path. So the bottom line is that you have to use the API correctly if you wish to deal correctly with long paths, either for creation or opening. This can pose some difficulties, as not all of the API calls are available if long paths are used. It also understandably gives anti-virus software some problems, as those apps probably have a primary target platform of Win9x/ME. This issue comes up every few years - it ought to be in a FAQ somewhere. Perhaps I'll give it some coverage in the next edition of 'Writing Secure Code". David LeBlanc dleblanc@mindspring.com
