Italian letter given to to Glib::ustring causes Glib::ConvertError

[Giuseppe Penone <giuspen gmail com>]

Hi,
I receive a terminate called after throwing an instance of 'Glib::ConvertError'
after assigning a string containing an italian character to Glib::ustring.
Can anybody help me to understand what I'm doing wrong?

//-----------------------------------------------------------------------------------------------------------
// g++ centro.cc -o centro `pkg-config --cflags --libs glibmm-2.4 giomm-2.4`

#include <iostream>
#include <glibmm.h>

using namespace std;

int  main(int argc, char *argv[])
{
    Glib::ustring  test = "funzionalità";
    cout << test << endl;
    return 0;
}
//----------------------------------------------------------------------------------------------------------

Thanks in advance,
Giuseppe.