Adds a string to be displayed in --help output before the list of options. This is typically a summary of the program functionality. Note that the summary is translated (see set_translate_func(), set_translation_domain()). Since: 2.14 a string to be shown in --help output before the list of options Returns: the summary See set_summary() for more information the summary Since: 2.14 Adds a string to be displayed in --help output after the list of options. This text often includes a bug reporting address. Note that the summary is translated (see set_translate_func()). Since: 2.14 a string to be shown in --help output after the list of options Returns: the description See set_description() for more information the description Since: 2.14 A convenience function to use gettext() for translating user-visible strings. Since: 2.14 the domain to use Return value: the value associated with the key as a double, or a #GKeyFile a group name a key return location for a #GError the value associated with the key as a double, or 0.0 if the key was not found or could not be parsed. Since: 2.14 Associates a new double value with @key under @group_name. If @key cannot be found then it is created. Since: 2.14 a #GKeyFile a group name a key an double value Loads a key file into an empty KeyFile instance. If the file could not be loaded then a FileError or KeyFileError exception is thrown. @throw Glib::FileError @throw Glib::KeyFileError an empty #GKeyFile struct the path of a filename to load, in the GLib file name encoding flags from #GKeyFileFlags return location for a #GError, or %NULL %TRUE if a key file could be loaded, %FALSE othewise Since: 2.6 Returns the value associated with @key under @group_name. @throw Glib::FileError in the event the key cannot be found (with the Glib::KEY_FILE_ERROR_KEY_NOT_FOUND code). @throw Glib::KeyFileError in the event that the @group_name cannot be found (with the Glib::KEY_FILE_ERROR_GROUP_NOT_FOUND). a #GKeyFile a group name a key return location for a #GError, or %NULL The value as a string. Since: 2.6