Spinning up a new Thread - do I need to care about garbage collection

Question

I'm having a bit of a brain-freeze so I thought I'd throw this out there to the collective genius of SO...

I have an event that is raised (this will be on the thread of the "raiser") and I consume it.

However, once I am handling this event, I need to fire off another thread to perform the workload that the event signified. So, I'm using:

private void MyEventHandler(object sender, EventArgs e)
{
    Thread t = new Thread(new ThreadStart(MyHandler));
    t.Start();
}

private void MyHandler()
{
    DoStuff(); // takes a long time
}

My question is: Do I need to be concerned about the lifecycle of the variable t? i.e. Can t be garbage collected, thus aborting the work being performed in DoStuff()?

Maybe my answer is here? http://stackoverflow.com/questions/81730/what-prevents-a-thread-in-c-from-being-collected — , Jun 07 '11 at 16:52
And the answer to this one? http://stackoverflow.com/questions/1036403/will-net-garbage-collect-an-object-thats-not-referenced-but-has-a-thread-that — , Jun 07 '11 at 16:54
Yes, that's the answer. A thread is not garbage collected until its work is finished. — Centro, Jun 07 '11 at 16:56
See this [answer](http://stackoverflow.com/questions/81730/what-prevents-a-thread-in-c-from-being-collected) — ribram, Jun 07 '11 at 16:54

score 8 · Accepted Answer · answered Jun 07 '11 at 16:55

8

There's no particular reason that you need to keep track of the Thread variable. The GC won't kill the thread when t goes out of scope.

I don't know how long "a long time" is, but you might be better off using something like ThreadPool.QueueUserWorkItem. That is:

private void MyEventHandler(object sender, EventArgs e)
{
    ThreadPool.QueueUserWorkItem(MyHandler);
}

private void MyHandler(object state)
{
    DoStuff();
}

answered Jun 07 '11 at 16:55

Jim Mischel

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I like this answer - it is the most conclusive. – Jun 07 '11 at 17:12

score 1 · Answer 2 · answered Jun 07 '11 at 16:56

If I understand correctly you are afraind that the Thread may be Garbage Collected while it is still working. And that would happen because after the method exits there is no reference to t.

But you need not to be afraid. As long as the thread is running there will be a reference to it and the thread will not be garbage collected.

score 0 · Answer 3 · answered Jun 07 '11 at 16:55

Can the thread work and objects be GCed? Yes. Will it happen automatically? Once the thread is complete.

But if this is a really long process that does not indicate failure back to the thread, it could potentially lock up resources indefinitely.

In these cases, a callback mechanism may be a better solution to leaving a thread open for an indefinte period.

Spinning up a new Thread - do I need to care about garbage collection

3 Answers3