LongPath and UNC paths

A colleague of mine started using the LongPath package provided as part of the Base Class Libraries project in CodePlex. This package seemed to be working just fine when trying to access local folders, both long and short. However, the provided code does not work with UNC paths – paths that are in the format of \\server\\share\\

A quick Bing search brought me to the MSDN page named Naming Files, Paths, and Namespaces that gives a lot of background on filenames, paths, and limitations, which includes the following section:

The \\? prefix can also be used with paths constructed according to the universal naming convention (UNC).
To specify such a path using UNC, use the \\?\\UNC prefix. For example, \\?\\UNC\\server\\share, where server is the name of the computer and share is the name of the shared folder. These prefixes are not used as part of the path itself. They indicate that the path should be passed to the system with minimal modification, which means that you cannot use forward slashes to represent path separators, or a period to represent the current directory, or double dots to represent the parent directory. Because you cannot use the \\? prefix with a relative path, relative paths are always limited to a total of MAX_PATH characters.

Usually, handling long paths is done by adding a prefix – \\? – to the path. Meaning, the path D:\LongFolderName will become \\?\\D:\LongFolderName

Handling UNC paths is a little different – you need to add a different prefix – \\?\\UNC which means that \\server\\share becomes \\?\\UNC\server\share