generic
      type Data_Type (<>) is private;
   package Timeout is

type Data_Type (<>) is private;

type Callback is access function (D : Data_Type) return Boolean;

type Destroy_Callback is access procedure (D : in out Data_Type);

function Add 
(
Interval
: Guint32;
Func
: Callback;
D
: Data_Type;
Destroy
: Destroy_Callback := null) return Timeout_Handler_Id;