C#•2y ago

❔ Why deconstuctor/Finalize example not working in vs 2022. Anything missing

using System;

class GCcollection
{
    public GCcollection()
    {
        Console.WriteLine("Hey why are u creating me"); 
    }

    ~GCcollection()
    {
        Console.WriteLine("Life is over, BYe");
    }
}

class AsUsualMainClass
{
    public static void Main(string[] args)
    {
        DoStuf();
    }

    public static void DoStuf()
    {
         var create = new GCcollection();
        create = null;
        GC.Collect();
        Console.ReadKey();
    }
}

using System;

class GCcollection
{
    public GCcollection()
    {
        Console.WriteLine("Hey why are u creating me"); 
    }

    ~GCcollection()
    {
        Console.WriteLine("Life is over, BYe");
    }
}

class AsUsualMainClass
{
    public static void Main(string[] args)
    {
        DoStuf();
    }

    public static void DoStuf()
    {
         var create = new GCcollection();
        create = null;
        GC.Collect();
        Console.ReadKey();
    }
}

7 Replies

Raki•2y ago

I'm just pressing F5 to run this but Ideally the deconstructor should be called when GC.Collect executes but in my console window. I don't see it

cap5lut•2y ago

generally speaking you should not rely on finalizers, but use the dispose pattern instead https://learn.microsoft.com/en-us/dotnet/standard/garbage-collection/implementing-dispose

Implement a Dispose method

In this article, learn to implement the Dispose method, which releases unmanaged resources used by your code in .NET.

Florian Voß•2y ago

@ramji it seems you just have to move the garbage collection outside of its scope, and add a little delay to give the finalizer thread enough time to finish it's work:

class AsUsualMainClass
{
    public static void Main(string[] args)
    {
        DoStuf();
        GC.Collect();
        Thread.Sleep(1000);
    }

    public static void DoStuf()
    {
        var create = new GCcollection();
        create = null;
    }
}

class AsUsualMainClass
{
    public static void Main(string[] args)
    {
        DoStuf();
        GC.Collect();
        Thread.Sleep(1000);
    }

    public static void DoStuf()
    {
        var create = new GCcollection();
        create = null;
    }
}

this works as expected there is also GC.WaitForPendingFinalizers() to make it not as hardcoded

Chiyoko_S•2y ago

Finalizers are not run immediately after they are collected if the GC finds an object that has a finalizer & is not referenced anywhere, the object with the finalizer is put on a finalization queue to have its resource cleaned up then unallocated... eventually there is no guarantees on when the finalizer will run which is why you should avoid relying solely on finalizers, and use Dispose() patterns instead; the resource clean-ups are deterministic this way (because you do the clean-up yourself) also rarely is there a need to write finalizers yourself. You should never write your own unless you are doing the unmanaged resource management yourself

JakenVeina•2y ago

Finalizers are not guaranteed to run, ever, no matter what you do

JakenVeina•2y ago

https://ericlippert.com/2015/05/18/when-everything-you-know-is-wrong-part-one/

ericlippert

Fabulous adventures in coding

When everything you know is wrong, part one

Finalizers are interesting and dangerous because they are an environment in which everything you know is wrong. I’ve written a lot about the perils of C# finalizers / destructors (either name…

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Why deconstuctor/Finalize example not working in vs 2022. Anything missing