---
title: "AudioFileOpenWithCallbacks(_:_:_:_:_:_:_:)"
framework: audiotoolbox
role: symbol
role_heading: Function
path: "audiotoolbox/audiofileopenwithcallbacks(_:_:_:_:_:_:_:)"
---

# AudioFileOpenWithCallbacks(_:_:_:_:_:_:_:)

Opens an existing file with callbacks you provide.

## Declaration

```swift
func AudioFileOpenWithCallbacks(_ inClientData: UnsafeMutableRawPointer, _ inReadFunc: AudioFile_ReadProc, _ inWriteFunc: AudioFile_WriteProc?, _ inGetSizeFunc: AudioFile_GetSizeProc, _ inSetSizeFunc: AudioFile_SetSizeProc?, _ inFileTypeHint: AudioFileTypeID, _ outAudioFile: UnsafeMutablePointer<AudioFileID?>) -> OSStatus
```

## Parameters

- `inClientData`: A pointer to a constant passed to your callbacks. The constant should contain any information you use to manage the state for reading data from the file.
- `inReadFunc`: A callback function invoked when the audio file object wants to read data.
- `inWriteFunc`: A callback function called when the audio file object wants to write data.
- `inGetSizeFunc`: A callback function called when the audio file object wants to know the file size.
- `inSetSizeFunc`: A callback function called when the audio file object wants to set the file size.
- `inFileTypeHint`: A hint about the type of the designated file. For files with no filename extension and without a type easily or uniquely determined from the data (ADTS,AC3), use this hint to indicate the file type. Otherwise, pass 0 for this parameter. The hint is only available in macOS versions 10.3.1 or greater. In versions prior to OS X 10.3.1, opening files such files fails.
- `outAudioFile`: On output, a pointer to the newly opened file.

## Return Value

Return Value A result code. See Result Codes.

## See Also

### Related Documentation

- [AudioFileInitializeWithCallbacks(_:_:_:_:_:_:_:_:_:)](audiotoolbox/audiofileinitializewithcallbacks(_:_:_:_:_:_:_:_:_:).md)

### Opening and Closing Audio Files

- [AudioFileOpenURL(_:_:_:_:)](audiotoolbox/audiofileopenurl(_:_:_:_:).md)
- [AudioFileClose(_:)](audiotoolbox/audiofileclose(_:).md)