How to stop a thread running a blocking method

Question

I'm making a server application and I'm using a thread running in a while(true) a blocking listening function.

How can I stop the thread? I can't use this kind of code:

while(true)
{
    BlockingMethod();
    if(shouldStop)
        return;
}

Because it will be executed till BlockingMethod "unblocks"...

So you want to stop the thread even if it's busy doing something inside the BlockingMethod()? — Saverio Terracciano, Jun 17 '14 at 19:19
Yes, because when the user stops the application (made with WPF), the process is still running... — Adrien Neveu, Jun 17 '14 at 19:20
possible duplicate of [C# How to kill a blocked thread?](http://stackoverflow.com/questions/5560817/c-sharp-how-to-kill-a-blocked-thread) — Yuval Itzchakov, Jun 17 '14 at 19:26
@ApocKalipsS duration between your comments is 7 mins. So this shows, it is not much harder then answering. — L.B, Jun 17 '14 at 19:42
Can you 'artificially' satisfy the blocking conditiion from another thread? What does the blocking call do - what does it wait on? — Martin James, Jun 18 '14 at 10:08

Saverio Terracciano · Accepted Answer · 2014-06-17T19:35:40.607

2

It's not a good practice, and you should avoid it if possible, but you can call the Thread.Abort() method if you have no way to stop the BlockingMethod().

Info on it here: http://msdn.microsoft.com/en-us/library/cyayh29d(v=vs.110).aspx

I'd advise you to try to change your BlockingMethod() in a way you can pass a Cancellation Token and abort it in a graceful way.

As Yuval Itzchakov specified, "if he passes a CancellationToken he has to actively check on it from time to time. It wont work if the method blocks. If you choose to use Thread.Abort() make sure you catch (ThreadAbortException) and set Thread.ResetAbort" and "Task.Run with a cancellation token can take care of it, if the Task is cancelled prior to the blocking call" (Pete Garofano).

edited Jun 17 '14 at 19:35

answered Jun 17 '14 at 19:22

Saverio Terracciano

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Even if he passes a `CancellationToken` he has to actively check on it from time to time. It wont work if the method blocks. If you choose to use `Thread.Abort()` make sure you `catch (ThreadAbortException)` and set `Thread.ResetAbort` – Yuval Itzchakov Jun 17 '14 at 19:26
Task.Run with a cancellation token will handle it. – Pete Garafano Jun 17 '14 at 19:26
Only if the `Task` was cancelled prior to the blocking call – Yuval Itzchakov Jun 17 '14 at 19:27
Expanded the answer with your suggestions. – Saverio Terracciano Jun 17 '14 at 19:35

score 0 · Answer 2 · answered Jun 17 '14 at 19:42

0

Use Thread.Join(TimeSpan) to give the thread a chance to end gracefully, followed by Thread.Abort()

answered Jun 17 '14 at 19:42

O.O

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How to stop a thread running a blocking method

2 Answers2