Question: How to check with WINAPI file path is disk or file or directory?

Answer: 
Use [GetFileAttributes](http://msdn.microsoft.com/en-us/library/aa364944(v=VS.85).aspx).

**Edit:** You can also check [SHGetFileInfo](http://msdn.microsoft.com/en-us/library/bb762179(v=VS.85).aspx)
See if the path has a drive letter in front of it? All UNC's take the form "\\server\share\file\_path" No drive letter.

Out of curiousity I looked this up. Based on this MSDN article [**Naming Files, Paths, and Namespaces**](http://msdn.microsoft.com/en-us/library/aa365247%28v=VS.85%29.aspx), it seems my advice is exactly how it says it should be done.