Mac Apps That Use Garbage Collection Must Move to ARC

[Paulo Pinto via Digitalmars-d]

On Tuesday, 24 February 2015 at 07:53:52 UTC, Jacob Carlborg 
wrote:
> On 2015-02-23 21:30, Walter Bright wrote:
>
>> Count me among those.
>>
>> In Java, write barriers make sense because Java uses the GC for
>> everything. Pretty much every indirection is a GC reference.
>>
>> This is not at all true with D code. But since the compiler 
>> can't know
>> that, it has to insert write barriers for all those 
>> dereferences
>> regardless.
>
> The alternative would be to have two kind of pointers, one for 
> GC allocated data and one for other kind of data. But I know 
> you don't like that either.
>
> We kind of already have this, class references and regular 
> pointers. But that would tie classes to the GC.
>
>> I suspect it would be a terrible performance hit.
>
> It would be nice to have some numbers backing this up.


This the approach taken by Active Oberon and Modula-3.

Pointers are GC by default, but can be declared as untraced 
pointers in code considered @system like in D.

--
Paulo