Creates a new closure which invokes the function found at the offset struct_offset in the class structure of the interface or classed type identified by itype.
the GType identifier of an interface or classed type
the offset of the member function of itype's class structure which is to be invoked by the new closure
a floating reference to a new gobject.CClosure
Creates a new closure which invokes the function found at the offset struct_offset in the class structure of the interface or classed type identified by itype.