There is a length limit to Windows file extensions?

If I want to create a new file extension for a binary/text data file that will open on my own application (extension ".mylongfileextensionname" for example), will Windows list it with my aplication (considering that I already listed it on Windows Registry before)? There is a length limit, I mean, on my example should I use ".mylong" or any specific layout?

Answer

I always thought 255 total as in Breakthrough's answer but I found this to be contradictory as I started to double-check my thoughts:

Windows 2000 has a 254 character limit.
Windows XP has a 255 character limit.
Windows Vista and Windows 7 has a 260 character limit.

Path+Filename limit is 260 characters.

http://www.wincert.net/tips/microsoft-windows/windows-7/2427-windows-7-file-transfer-issue-destination-path-too-long.html

Confirmed on this Microsoft site:

http://windows.microsoft.com/en-US/windows-vista/File-names-and-file-name-extensions-frequently-asked-questions (expand "What is the maximum length of a file name?")

http://msdn.microsoft.com/en-us/library/aa365247(v=vs.85).aspx