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# AudioFile_GetSizeProc

Gets file data size.

```
typealias AudioFile_GetSizeProc = (UnsafeMutableRawPointer) -> Int64
```

## Parameters

`inClientData`

A pointer to the client data as set in the `inClientData` parameter to the [`AudioFileOpenWithCallbacks(_:_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioFileOpenWithCallbacks(_:_:_:_:_:_:_:)) or [`AudioFileInitializeWithCallbacks(_:_:_:_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioFileInitializeWithCallbacks(_:_:_:_:_:_:_:_:_:)) functions.

## Return Value

The callback should return the size of the data.

## Discussion

If you named your function `MyAudioFile_GetSizeProc`, you would declare it like this:

### Discussion

This callback gets invoked by an audio file object when it needs to get audio file data size. You pass this callback as a parameter when calling the [`AudioFileOpenWithCallbacks(_:_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioFileOpenWithCallbacks(_:_:_:_:_:_:_:)) and [`AudioFileInitializeWithCallbacks(_:_:_:_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioFileInitializeWithCallbacks(_:_:_:_:_:_:_:_:_:)) functions.

---

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