### - o -

- OBJECT_PATH_IN_USE : Gio::DBus::Error
- OCTOBER : Glib::Date
- OPTIMIZE : Glib::RegexError
- OPTION_TYPE_BOOL : Gio::Application
- OPTION_TYPE_DOUBLE : Gio::Application
- OPTION_TYPE_FILENAME : Gio::Application
- OPTION_TYPE_FILENAME_VECTOR : Gio::Application
- OPTION_TYPE_INT : Gio::Application
- OPTION_TYPE_INT64 : Gio::Application
- OPTION_TYPE_STRING : Gio::Application
- OPTION_TYPE_STRING_VECTOR : Gio::Application
- OVERFLOWN : Glib::IOChannelError