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.
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
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.