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# CFRunLoopStop(_:)

Forces a CFRunLoop object to stop running.

```
func CFRunLoopStop(_ rl: CFRunLoop!)
```

## Parameters

`rl`

The run loop to stop.

## Discussion

This function forces `rl` to stop running and return control to the function that called [`CFRunLoopRun()`](/documentation/CoreFoundation/CFRunLoopRun()) or [`CFRunLoopRunInMode(_:_:_:)`](/documentation/CoreFoundation/CFRunLoopRunInMode(_:_:_:)) for the current run loop activation. If the run loop is nested with a callout from one activation starting another activation running, only the innermost activation is exited.

---

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