Indeed, so your example fails and it also proves that you should not use / in Windows.
I found a little quote in the doc:
So / works for paths with API, but not outside. So it's highly recommended not to use / for paths.Note Functions in the Windows API convert "/" to "\" as part of converting the name to an NT style name.
I don't know if WINE emulates this behavior, as well.
Using / for paths has always annoyed me anyway for some reason.