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What are cancellation tokens used for?
A CancellationToken enables cooperative cancellation between threads, thread pool work items, or Task objects. You create a cancellation token by instantiating a CancellationTokenSource object, which manages cancellation tokens retrieved from its CancellationTokenSource.
What is a cancellation token?
A cancellation token ( CancellationToken ) which provides each operation with a way to register for cancellation notifications. A cancellation token source ( CancellationTokenSource ) which manages tokens and sends cancellation notifications to each of the cancellation tokens.
What is thread cancellation and its types?
Cancellation of a target thread may occur in two different cases − Asynchronous cancellation − One thread terminates immediately the target thread. Deferred cancellation − The target thread checks periodically whether it should terminate, allowing it an opportunity to terminate itself in an orderly fashion.
Do you have to pass cancellation token to task?
You have to pass the CancellationToken to the Task, which will periodically monitors the token to see whether cancellation is requested. In this case, the operation will end when cancellation is requested and the Task will have a RanToCompletion state.
What happens when the associated cancellationtoken is cancelled?
An aggregate exception containing all the exceptions thrown by the registered callbacks on the associated CancellationToken. The associated CancellationToken will be notified of the cancellation and will transition to a state where IsCancellationRequested returns true.
What does it mean to cancel a task in MSDN?
Task Cancellation. If you are waiting on a Task that transitions to the Canceled state, a System.Threading.Tasks.TaskCanceledException exception (wrapped in an AggregateException exception) is thrown. Note that this exception indicates successful cancellation instead of a faulty situation.
What’s the best way to not check cancellationtoken?
Consider not checking the token at all if your work is very quick, or you propagate it to the methods you call. That said, calling CancellationToken.ThrowIfCancellationRequested () is pretty lightweight so don’t think too hard about this one unless you see it on perf traces.