AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2004.10.01 16:41 "[Tiff] Re: BigTIFF extension issue", by Ian Ameline
[...]
2004.10.04 15:23 "Re: [Tiff] Re: BigTIFF extension issue", by Joris
2004.10.04 15:43 "Re: [Tiff] Re: BigTIFF extension issue", by Bob Friesenhahn
2004.10.04 15:54 "Re: [Tiff] Re: BigTIFF extension issue", by Joris
[...]

2004.10.04 15:43 "Re: [Tiff] Re: BigTIFF extension issue", by Bob Friesenhahn

With Microsoft Windows we are blessed with an operating system which supports long file names, but only looks at the first three characters of the file extension when it decides what to do. In this case a ".bigtif" exension would be treated as the extension ".big" by Windows.

Untrue, I believe. What is your source on this?

I have encountered this problem with FindFirstFile (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/findfirstfile.asp).

The problem was encountered under Windows XP. Note that Windows still supports "short names" (8+3) which only support three character extensions. When testing for short names (support apparently can not be disabled), the existing long extension is truncated to just three characters. The legacy 8+3 support continues to permiate Windows and influence how it works.

This means that an application which requests to find files matching ".tif" will also return files with extension ".tifb" and that ".bigtiff" would be treated the same as ".big".

The upshot is that it is very wise to use an extension which does not collide with any other common/known extension in the first three characters.

Bob
======================================
Bob Friesenhahn
bfriesen@simple.dallas.tx.us
http://www.simplesystems.org/users/bfriesen