Idomatic way to guarantee to run destructor?

[Robert M. Münch]

On 2020-04-30 17:45:24 +0000, Steven Schveighoffer said:

> No, auto is declaring that there's about to be a variable here. In 
> actuality, auto does nothing in the first case, it just means local 
> variable. But without the type name, the type is inferred (i.e. your 
> second example). This does not do any automatic destruction of your 
> class, it's still left to the GC.

Ok, that was my understand too. As said, I found some older posts and 
was a bit confused...

> You can use scope instead of auto, and it will then allocate the class 
> on the stack, and destroy it as Ben Jones said. There is danger there, 
> however, as it's very easy to store a class reference elsewhere, and 
> then you have a dangling pointer.

Ok. Can't this be combined with some "don't let the refrence escape my 
function" feature of D?

> A safer thing to do is:
> 
> auto X = new MyClass();
> scope(exit) destroy(X);
> 
> This runs the destructor and makes the class instance unusable, but 
> does not free the memory (so any remaining references, if used, will 
> not corrupt memory).

How would that help, because the class instance is now unusable anyway. 
So I have it around like a zombie and others might think: "Hey you look 
normal, let's get in contact" and then you are doomed...

> If your concern is guaranteeing destructors are run, that's what I 
> would pick. If in addition you want guaranteed memory cleanup, then use 
> scope (and be careful).

Ok, thanks.

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster
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