Why don't wide characters work with libstdc++?

The wide-character parts of the GCC Standard C++ Library (libstdc++) have not yet been fully ported to Windows, so you cannot use most of these features with MinGW. If you try to use things like

std::wcout

or

basic_string<wchar_t>

then you will probably get compiler or linker errors.

This has been discussed frequently on the mailing lists; e.g. see:
http://thread.gmane.org/gmane.comp.gnu.mingw.user/10818
http://thread.gmane.org/gmane.comp.gnu.mingw.user/12917

If you really need these features then one alternative is to use the STLPort library from http://www.stlport.org/ instead of libstdc++.