Sets our main struct and passes it to the parent class.
Get the main Gtk struct
the main Gtk struct as a void*
the main Gtk struct
the main Gtk struct
Get the main Gtk struct
the main Gtk struct as a void*
Retrieves the GtkWidget associated to the given @layout_child.
Retrieves the GtkLayoutManager instance that created the given @layout_child.
GtkLayoutChild subclass for children in a GtkConstraintLayout.