[Lazarus] IUnknown and reference counting

[Sven Barth]

Am 21.03.2013 11:36, schrieb Hans-Peter Diettrich:
> Michael Schnell schrieb:
>> BTW.: Re. COM / CORBA / ORB
>>
>> Is there a decent way to describe the internal *Language-concept* 
>> (Interface, Interfaced object, ....) (i.e. keywords, syntax, 
>> features, usability...) independently of paradigms dictated by the 
>> environment the executable is supposed to run in and that might 
>> provide some useful parameters to the IDE when designing the program 
>> ? Based on this, COM / CORBA / ORB might be described as 
>> specializations of the concept.
>
> Simply forget about COM/CORBA ;-)
>
> As already mentioned, Delphi interfaces are the workaround for the 
> missing multiple inheritance in OPL, as known from many languages 
> (Java...). Everything else IMO is language/implementation specific.
Delphi's interfaces are more than that. They also add reference 
counting. If you just want plain interfaces like in Java and other 
languages than you need to use what is called "CORBA" interfaces in FPC.
>
> The lifetime of interfaces and their underlying objects is managed by 
> reference counting in OPL. IMO this is essential for safe use of 
> interfaces, because no holder of an interface reference can know when 
> the underlying object can or should be destroyed.
Only when "COM" style interfaces are used.

Regards,
Sven