$clipboard = Gtk::Clipboard.get('PRIMARY')... under windows

I need to be able to read text that has been selected in another
application under windows. Using $clipboard =
Gtk::Clipboard.get(‘PRIMARY’) works fantastically well under Linux, but
I’d like my application to work on both Windows and Linux. I noticed in
the documentation that the afforementioned only works with X and that it
is completely ineffective under win32, but there are no workarounds
suggested…

Does anyone have one? Is this just completely impossible to do in
Windows?