Escaping the Tyranny of the GC: std.rcstring, first blood

[Dmitry Olshansky via Digitalmars-d]

27-Sep-2014 12:11, Foo пишет:
>> Consider:
>>
>> struct MyRefCounted
>>     void opInc();
>>     void opDec();
>>     int x;
>> }
>>
>> MyRefCounted a;
>> a.x = 42;
>> MyRefCounted b = a;
>> b.x = 43;
>>
>> What is a.x after this?
>>
>>
>> Andrei
>
> a.x == 42
> a.ref_count == 1 (1 for init, +1 for copy, -1 for destruction)
> b.x == 43
> b.ref_count == 1 (only init)

There is no implicit ref-count. opInc may just as well create a file on 
harddrive and count refs there. Guaranteed it would be idiotic idea, but 
the mechanism itself opens door to some cool alternatives like:

- separate tables for ref-counts (many gamedevs seem to favor this, also 
see Objective-C)
- use padding of some stuff for ref-count
- may go on and use e.g. 1 byte for ref-count on their own risk, or even 
a couple of bits here and there

I may go on, and on. But also consider:

GObject of GLib (GNOME libraries)
XPCOM (something I think Mozila did as sort-of COM)
MS COM
etc.

Refcounting is process of add(x), and sub(x), and calling destructor 
should the subtract call report zero. Everything else is in the hands of 
the creator.

-- 
Dmitry Olshansky