gtkmm and Win32
One of the major advantages of gtkmm is that it is crossplatform. gtkmm programs written on other platforms such as GNU/Linux can generally be transferred to Windows (and vice versa) with few modifications to the source.
gtkmm currently works with the MingW/GCC3.4 compiler and Microsoft Visual C++ 2005 or later (including the freely available express editions) on the Windows platform. There is an installer available for gtkmm on Microsoft Windows. Refer to https://wiki.gnome.org/Projects/gtkmm/MSWindows for instructions how to use it.

Building gtkmm on Win32
Please see https://wiki.gnome.org/Projects/gtkmm/MSWindows/BuildingGtkmm for instructions on how to build gtkmm on Windows.