CODEWITHSUNDEEP
windowsfilenamesmaxlength
Alex
Alex

Reputation: 245

On Windows, what is the maximum file name length considered acceptable for an app to output? (Updated and clarified)

Many Windows applications (e.g., almost all .NET apps) cannot open paths more than 260 characters in length. I am batch renaming a list of podcast files. I want to name each file after the title of the episode, but the titles are up to 100 characters long. This means that if a user saves the file in a deep directory with a very long path, they may hit the limit and be unable to open the file in those other applications.

Is it acceptable for my program to put out file names this long, and leave it to the user to deal with very long paths when it comes up? iTunes crops at 40 chars, but that seems very conservative.

Thanks to Ben Voigt for clarifying that this only applies to certain apps.

Upvotes: 7

Views: 8581

Answers (2)

Ben Voigt
Ben Voigt

Reputation: 283634

Windows does NOT have a limit of 255 characters for file paths.

CreateFileA has a limit of 260 characters. CreateFileW supports names up to about 32760 characters (64kB).

Some filesystems impose additional limits on the maximum directory nesting level, or the maximum length of each part.

You're probably thinking of certain popular Windows programs that have a 255 character limit, but accommodating those with a warning or user-configurable setting is probably more appropriate than adding your own hard limit.

Upvotes: 4

Tixz
Tixz

Reputation: 135

Well I remember having an USB that didn't support more than 32 characters in the filename (can't remember which FS it had). I also just found this link on Google: http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx

Character count limitations can also be different and can vary depending on the file system and path name prefix format used. This is further complicated by support for backward compatibility mechanisms. For example, the older MS-DOS FAT file system supports a maximum of 8 characters for the base file name and 3 characters for the extension, for a total of 12 characters including the dot separator. This is commonly known as an 8.3 file name. The Windows FAT and NTFS file systems are not limited to 8.3 file names, because they have long file name support, but they still support the 8.3 version of long file names.

Upvotes: 0

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