Accessor of the slot parent of the gtk-widget class.
The generic function gtk-widget-parent returns the parent container of widget.
The generic function (setf gtk-widget-parent) sets the container as the parent of widget, and takes care of some details such as updating the state and style of the child to reflect its new location. The opposite function is gtk-widget-unparent.
This function is useful only when implementing subclasses of gtk-container.