generic
      type User_Data_Type (<>) is private;
      with procedure Destroy (Data : in out User_Data_Type) is null;
   package Set_Destroy_Count_Func_User_Data is

type User_Data_Type (<>) is private;

type Gtk_Tree_Destroy_Count_Func is access procedure
        (Tree_View : not null access Gtk.Tree_View.Gtk_Tree_View_Record'Class;
         Path      : Gtk.Tree_Model.Gtk_Tree_Path;
         Children  : Gint;
         User_Data : User_Data_Type);

procedure Destroy 
(
Data
: in out User_Data_Type) is null;

procedure Set_Destroy_Count_Func 
(
Tree_View
: not null access Gtk.Tree_View.Gtk_Tree_View_Record'Class;
Func
: Gtk_Tree_Destroy_Count_Func;
Data
: User_Data_Type);