A properly internationalized application will not make assumptions about the
number of bytes in a character. That means that you shouldn't use pointer
arithmetic to step through the characters in a string, and it means you
shouldn't use std::string
or standard C functions such
as strlen()
because they make the same assumption.
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
.
Unfortunately, the integration with the standard iostreams is not completely
foolproof. gtkmm converts Glib::ustring
s to a
locale-specific encoding (which usually is not UTF-8) if you output them to an
ostream
with operator<<
.
Likewise, retrieving Glib::ustring
s 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()));