• Ingmar Schuster <ingmar.schuster web.de> Dec 08 2005
• David Friedman <d3rdclsmail_a_ _t_earthlink_d_._t_net> Dec 10 2005

Hi,

A quick-and-easy question on the implementation of interfaces in gdc: 
hows it done, with multiple inheritance, interface dispatch tables like 
in gcj or some third method?

Greetings
Ingmar Schuster

Ingmar Schuster wrote:
 Hi,
 
 A quick-and-easy question on the implementation of interfaces in gdc: 
 hows it done, with multiple inheritance, interface dispatch tables like 
 in gcj or some third method?
 
 Greetings
 Ingmar Schuster


Basically, it's multiple inheritance.

When a class is declared to implement an interface, a field is added to 
the class that points to a virtual method table for that interface.  If 
an interface is reimplemented in a descendant class, another field is 
added instead of using the one from the ancestor class.  Both fields 
will have the same value.

Except for COM interfaces, the first entry of the interface virtual 
method table points to some information that can be used to cast the 
interface reference back to its object reference.

David