glibmm: New API in glibmm 2.56

glibmm 2.76.0

New API in glibmm 2.56

Member Gio::Application::set_option_context_description (const Glib::ustring & description)
Member Gio::Application::set_option_context_parameter_string (const Glib::ustring & parameter_string)
Member Gio::Application::set_option_context_summary (const Glib::ustring & summary)
Member Gio::DesktopAppInfo::get_locale_string (const Glib::ustring & key)
Member Glib::ConvertError::EMBEDDED_NUL
Member Glib::DateTime::create_from_iso8601 (const Glib::ustring & text, const TimeZone & default_tz)
Member Glib::DateTime::format (const Glib::ustring & format_str) const