const char* gtk_expander_get_label ( GtkExpander* expander )
Fetches the text from a label widget.
This is including any embedded underlines indicating mnemonics and
Pango markup, as set by
gtk_expander_set_label(). If the label
text has not been set the return value will be
NULL. This will be the
case if you create an empty button with
gtk_button_new() to use as a container.