gtk:tool-button-icon-name (object)

object -- a gtk:tool-button widget
name -- a string for the name of the themed icon

The accessor for the icon-name slot gets or sets the name of the themed icon for the tool button. See the docs for the gtk:icon-theme implementation for more details. The icon-name property only has an effect if not overridden by non-nil label, icon-widget and stock-id properties.