Blog: GC

[Dukc]

On Saturday, 6 March 2021 at 20:21:41 UTC, Rumbu wrote:
>
> I took the article with a grain of salt when I saw the author 
> claiming that finalisation of classes is a problem in all 
> garbage collected languages. It seems that the author failed to 
> update himself or - what's worse - wants to justify D failure 
> in having deterministic class destruction by pointing to others.
>
> C# has IDisposable/using and Java has AutoCloseable as 
> mechanisms for deterministic destruction.

Those C#/Java mechanisms are for deterministic destruction, akin 
to https://dlang.org/phobos/std_typecons.html#scoped. Mike warned 
only about indeterministic destructors -those that are only 
invoked when/if the object gets collected.

To be precise, class destructors are not any more problematic 
than struct desturctors if they are always called 
deterministically -see 
https://dlang.org/phobos/object.html#.destroy. But if the 
destructor needs to be called manually anyway, why should it be a 
destructor at all? It's probably better to put the finalizing in 
a normal function, or better yet to a destructor of a RAII struct.

Problems with GC-called destructors are not unique to D -see 
https://theartofmachinery.com/2018/12/05/gc_not_enough.html for a 
Ruby example.

> I remember when D had built-in allocator support and delete for 
> deterministic destructors. Now they are deprecated and we have 
> a library solution :)

I don't see why library solutions would be inherently inferior. 
What do we lose in case of deterministic destruction?