How to create directories in windows with path length greater than 256

In fact the limit on path strings is 260 characters. The underlying OS, these days, can support much longer path names, up to 32,767 characters. In order to name a path with a long name you need to use the magic \\?\ prefix, and use the Unicode version of the API.

However, many tools don't support such long names. A classic example of such a tool is Explorer which won't let you create objects with names longer than 260 characters. Because of this I strongly advise you to avoid creating such long names—doing so will save you much heartache in the long run.

This should get you started: http://msdn.microsoft.com/en-us/library/aa365247%28v=vs.85%29.aspx#maxpath

Sadly it's an issue that I don't think will be going away any time soon, so you'd do well to familiarize yourself with that stuff.

As an aside, if you have access to robocopy (comes packaged with Windows Vista and 7, but is also available for XP), which supports long paths, you could create your files/subfolders in a higher-up folder and then use robocopy to move the subfolder to its desired location deeper in the folder tree.