gtk:header-bar-has-subtitle (object)

object -- a gtk:header-bar widget
setting -- true to reserve space for a subtitle

Accessor of the has-subtitle slot of the gtk:header-bar class. The gtk:header-bar-has-subtitle function retrieves whether the header bar reserves space for a subtitle, regardless if one is currently set or not. The (setf gtk:header-bar-has-subtitle) function sets whether the header bar should reserve space for a subtitle.