Förvänta sig UTF8

Ett ordentligt internationaliserat program kommer inte göra antaganden om antalet byte i ett tecken. Detta betyder att du inte ska använda pekararitmetik för att stega genom tecknen i en sträng, och det betyder att du inte ska använda std::string eller C-standardfunktioner som strlen() för att de gör samma antagande.

However, you probably already avoid bare char* arrays and pointer arithmetic by using std::string, so you just need to start using Glib::ustring instead. See the Basics chapter about Glib::ustring.

Glib::ustring och std::iostreams

Unfortunately, the integration with the standard iostreams is not completely foolproof. gtkmm converts Glib::ustrings to a locale-specific encoding (which usually is not UTF-8) if you output them to an ostream with operator<<. Likewise, retrieving Glib::ustrings from istream with operator>> causes a conversion in the opposite direction. But this scheme breaks down if you go through a std::string, e.g. by inputting text from a stream to a std::string and then implicitly converting it to a Glib::ustring. If the string contained non-ASCII characters and the current locale is not UTF-8 encoded, the result is a corrupted Glib::ustring. You can work around this with a manual conversion. For instance, to retrieve the std::string from a ostringstream:

std::locale::global(std::locale("")); // Set the global locale to the user's preferred locale.
                                      // Usually unnecessary here, because Glib::init()
                                      // or Gtk::Application::create() does it for you.
std::ostringstream output;
output << percentage << " % done";
label->set_text(Glib::locale_to_utf8(output.str()));