### - u -

- UNKNOWN_ATTRIBUTE : Glib::MarkupError
- UNKNOWN_ELEMENT : Glib::MarkupError
- UNKNOWN_ENCODING : Glib::KeyFileError
- UNKNOWN_OPTION : Glib::OptionError
- UNKNOWN_POSIX_CLASS_NAME : Glib::RegexError
- UNKNOWN_PROPERTY : Glib::RegexError
- UNMATCHED_PARENTHESIS : Glib::RegexError
- UNRECOGNIZED_CHARACTER : Glib::RegexError
- UNRECOGNIZED_ESCAPE : Glib::RegexError
- UNTERMINATED_CHARACTER_CLASS : Glib::RegexError
- UNTERMINATED_COMMENT : Glib::RegexError