A GTypeInterface structure. [type GObject.TypeInterface]
The corresponding GTypeInterface structure of the parent type of the instance type to which g_iface belongs, or NULL if the parent type doesn't conform to the interface. [transfer none][type GObject.TypeInterface]
Returns the corresponding GTypeInterface structure of the parent type of the instance type to which g_iface belongs. This is useful when deriving the implementation of an interface from the parent type and then possibly overriding some methods.