---
title: AudioFile_GetSizeProc
framework: audiotoolbox
role: symbol
role_heading: Type Alias
path: audiotoolbox/audiofile_getsizeproc
---

# AudioFile_GetSizeProc

Gets file data size.

## Declaration

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

## Parameters

- `inClientData`: A pointer to the client data as set in the inClientData parameter to the doc://com.apple.audiotoolbox/documentation/AudioToolbox/AudioFileOpenWithCallbacks(_:_:_:_:_:_:_:) or doc://com.apple.audiotoolbox/documentation/AudioToolbox/AudioFileInitializeWithCallbacks(_:_:_:_:_:_:_:_:_:) functions.

## Return Value

Return Value The callback should return the size of the data.

## Discussion

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(_:_:_:_:_:_:_:) and AudioFileInitializeWithCallbacks(_:_:_:_:_:_:_:_:_:) functions.

## See Also

### Callbacks

- [AudioFile_ReadProc](audiotoolbox/audiofile_readproc.md)
- [AudioFile_WriteProc](audiotoolbox/audiofile_writeproc.md)
- [AudioFile_SetSizeProc](audiotoolbox/audiofile_setsizeproc.md)