Maximum number of characters in file name extension

Does Vista (& XP) set a limit on the maximum number of characters in a file
name extension? I know that XP will open files with 4 characters (for
example, .html). So, is there a maximum number of characters in a file name
extension? Does Vista (& XP) allow numeric characters or punctuation marks or
other typable characters? Does Vista (& XP) allow a combination of alphabetic
& numeric & alphanumeric characters in a file name extension?

Thank you.

"pc nerd" <> wrote ...
> Does Vista (& XP) set a limit on the maximum number of characters in a
> file
> name extension? I know that XP will open files with 4 characters (for

These limits are defined by the NTFS file system. Windows XP, Server 2003
and Vista all use version 3.1 of the NTFS file system.

NTFS naming convensions are described here:

Naming a File
http://msdn2.microsoft.com/en-us/library/aa365247.aspx

The total length of the filename (basename plus extension) is 255 chars.
There is not specific limit on the extension length (eg you could have say,
200 char basename and 55 char extension, or even 1 char basename and 254
char extension).

All pathnames must generally fit within MAX_PATH, which is 260 chars
includng the final NUL char.

Some other handy references:

How NTFS Works
http://technet2.microsoft.com/window....mspx?mfr=true

Making Room for Long Filenames
http://msdn2.microsoft.com/en-us/library/ms810456.aspx

Different conventions apply for FAT and FAT32 file systems, obviously. These
are pretty much in the legacy class, except for removable media like USB
drives. Vista SP1 will introduce support for the exFAT file system, for
flash drives and similar scenarios.

Hope it helps,

--
Andrew McLaren
amclar at optusnet dot com dot au

Does Windows set a limit on file extension length?

Not as such. Filename extensions are just the bit after the dot and
Windows just uses it as a guide as to what program to pass the file to
to open it. The whole thing counts as the file name. As long as the
filename (INCLUDING the directory path) doesn't exceed 255 characters
then you can have whatever you want).


> Does Vista (& XP) allow numeric characters or punctuation marks or
> other typable characters?

The operators like * / \ ? " <> aren't allowed because they are wild
cards (used by programs / command prompts to perform actions e.g. - *
means all - *.mp3 is all files ending with .mp3)

> Does Vista (& XP) allow a combination of alphabetic
> & numeric & alphanumeric characters in a file name extension?
>

What about .mp3? Last time I checked, XP could open my music files