Sets @icon as the widget used as icon on @button. If @icon_widget is %NULL the icon is determined by the #GtkToolButton:stock-id property. If the #GtkToolButton:stock-id property is also %NULL, @button will not have an icon.
the widget used as icon, or %NULL
2.4
See Implementation
Sets @icon as the widget used as icon on @button. If @icon_widget is %NULL the icon is determined by the #GtkToolButton:stock-id property. If the #GtkToolButton:stock-id property is also %NULL, @button will not have an icon.