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# invalidateAndCancel()

Cancels all outstanding tasks and then invalidates the session.

```
func invalidateAndCancel()
```

## Discussion

Once invalidated, references to the delegate and callback objects are broken. After invalidation, session objects cannot be reused.

To allow outstanding tasks to run until completion, call [`finishTasksAndInvalidate()`](/documentation/Foundation/URLSession/finishTasksAndInvalidate()) instead.

> Important:
> Calling this method on the session returned by the ``doc://com.apple.foundation/documentation/Foundation/URLSession/shared`` method has no effect.

---

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