ReRegisterForFinalize SuppressFinalize real life example

Question

I was just reading this article, “Garbage Collection: Automatic Memory Management in the Microsoft .NET Framework”, by Jeffrey Richter, and I couldn't think of any real life sample for using ReRegisterForFinalize or SuppressFinalize.

Could anyone provide me with some examples?

`SuppressFinalize` is common, but no idea when I'd want to use `ReRegisterForFinalize`. — CodesInChaos, Oct 22 '11 at 17:26

score 11 · Accepted Answer · answered Oct 22 '11 at 19:26

A handful of places it gets used in the .NET framework, always a good place to look. Basic patterns are:

a disposed object gets reused. The Dispose() method has called SuppressFinalize so it needs to be re-registered (NativeWindow, RequestContextBase, TaskExceptionHolder class)
the finalizer failed and caught an exception. Little to do but to retry later. That code is wrapped with if (!Environment.HasShutdownStarted && !AppDomain.CurrentDomain.IsFinalizingForUnload()) to make sure that doing this makes sense (DynamicResolver and LoaderAllocatorScout class)
the object participates in a caching scheme and gets re-cached (OverlappedData class)

score 3 · Answer 2 · answered Oct 22 '11 at 17:31

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The implementation of IDisposable often requires SuppressFinalize: look here or here for the code.

I don't have a good example on ReRegisterForFinalize now.

answered Oct 22 '11 at 17:31

Vlad

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OK 'SuppressFinalize' looks pretty strait-forward, after reading those samples. prevent the costly finalize method to be called if I dipspoed the object by myself. – Nahum Oct 22 '11 at 17:43

score 1 · Answer 3 · edited May 23 '17 at 11:59

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You need ReRegisterForFinalize when resurrecting an instance. Resurrection (mentioned in the linked article) is the action of re-rooting an object from its destructor (finalizer).

That only moves the question to "when would you resurrect an object". In my answer to this question I speculated that a connectionpool or similar construct might use it.

edited May 23 '17 at 11:59

Community

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answered Oct 22 '11 at 18:03

H H

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I still have no idea when would I want to use `ReRegisterForFinalize ` – Nahum Oct 22 '11 at 18:16
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In 'normal' application or library code you wouldn't. A ConnectionPool is a highly specialized piece of software. – H H Oct 22 '11 at 18:19

ReRegisterForFinalize SuppressFinalize real life example

3 Answers3