Menu
Why can not I create a deep path whose characters in path is more than 255 in NTFS File System? It seems a limits of FAT32, but also exist in NTFS? Can anyone provide some documents?
Many Thanks!
401
The maximum filename length on a NTFS partition is 256 characters, and 11 characters on FAT (8 character name, . , 3 character extension). NTFS filenames keep their case, whereas FAT filenames have no concept of case (however the case is ignored when performing a search etc on NTFS).
When you try to access file I/O on a specific path, the Windows API always checks if the path is longer than the MAX_PATH limit. Most standard applications, including Windows Explorer (File Explorer), do not work correctly with long path files exceeding 256 characters.
By default, Windows uses a path length limitation (MAX_PATH) of 256 characters: Naming Files, Paths, and Namespaces.
The Windows API imposes a maximum filename length such that a filename, including the file path to get to the file, can't exceed 255-260 characters.
The 260 character limitation is not a limitation of the file system, but of the Win32 API. Win32 defines MAX_PATH as 260 which is what the API is using to check the length of the path passed into functions like FileCreate, FileOpen, etc. (which are used by .NET in the BCL).
However, you can bypass the Win32 rules and create paths up to 32K characters. Basically you need to use the "\\?\C:\MyReallyLongPath\File.txt" syntax which you may not have seen before. Last I checked, the File and FileInfo classes in .NET prevented you from using this type of path, but you can definitely do it from C/C++. Here's a link for more info.
http://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx
120
Quoted from wikipedia
File names are limited to 255 UTF-16 code words. Certain names are reserved in the volume root directory and cannot be used for files. These are: $MFT, $MFTMirr, $LogFile, $Volume, $AttrDef, . (dot), $Bitmap, $Boot, $BadClus, $Secure, $Upcase, and $Extend;[3] . (dot) and $Extend are both directories; the others are files. The NT kernel limits full paths to 32,767 UTF-16 code words.
http://en.wikipedia.org/wiki/NTFS
32
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
