Should I bother calling dispose on objects which share lifetime of process?

Question

I am aware that all objects which implement IDisposable should be disposed of as soon as they are no longer needed in order to free the memory used by their unmanaged resources.

My question relates to objects which I know for a fact will live until the host process itself is terminated. Would it make any difference if I dispose of them or not? Is there any chance of memory not being freed when the process dies? What about GDI objects? Would the GDI handles be freed when the process dies even if they were not disposed?

I fully understand that it is good practice to dispose of all objects anyways. I ask purely out of curiosity.

Answer 1

It depends on the object (resource) in question.

When a process terminates all unmanaged memory, filehandles and other OS resources will be released, even if the associated finalizers failed to run.

But I'm not so sure about db handles, named-mutexes etc.

So before you could consider it safe to not call Dispose, you would have to know about the resource type and how it relates to the process. Much easier to just call Dispose() out of general principle.

But it is a theoretical argument, most classes will use SafeHandle : CriticalFinalizerObject . So I don't think it ever is a real practical problem.

Answer 2

No. By design, IDisposable is available to allow a program to release an unmanaged resource early, earlier than it could be done by the finalizer. Which runs at a fairly unpredictable time, usually later whenever a garbage collection is performed. You cannot predict when that happens.

There's no point in disposing at program exit, the finalizer is guaranteed to run just before the AppDomain is unloaded and the process shuts down.

That's said, there is some IDisposable abuse about, code that actually expects you to call it. But that's typically based on the using statement, so not so likely you'll run into that.