---
title: "AudioFileGetUserDataAtOffset(_:_:_:_:_:_:)"
framework: audiotoolbox
role: symbol
role_heading: Function
path: "audiotoolbox/audiofilegetuserdataatoffset(_:_:_:_:_:_:)"
---

# AudioFileGetUserDataAtOffset(_:_:_:_:_:_:)

Gets part of the data from a chunk in an audio file.

## Declaration

```swift
func AudioFileGetUserDataAtOffset(_ inAudioFile: AudioFileID, _ inUserDataID: UInt32, _ inIndex: UInt32, _ inOffset: Int64, _ ioUserDataSize: UnsafeMutablePointer<UInt32>, _ outUserData: UnsafeMutableRawPointer) -> OSStatus
```

## Parameters

- `inAudioFile`: The audio file whose chunk you want to get data from.
- `inUserDataID`: The four-character code of the designated chunk.
- `inIndex`: An index that specifies which chunk with the four-character code specified in the inUserDataID parameter you want to query.
- `inOffset`: An offset from the first byte of the chunk to the first byte to get.
- `ioUserDataSize`: On input, a pointer to the size of the buffer that contains the designated chunk. On output, a pointer to the size of bytes that the system copied to the buffer.
- `outUserData`: A pointer to a buffer in which to copy the chunk data.

## Return Value

Return Value A result code if there’s an error (see Result Codes) or noErr if the operation succeeds.

## Discussion

Discussion See AudioFileGetUserDataSize64(_:_:_:_:) for an example of using this function to parse the Audio Definition Model (ADM) of a BW64 file, which is 64-bit and based on WAVE.

## See Also

### Working with User Data

- [AudioFileCountUserData(_:_:_:)](audiotoolbox/audiofilecountuserdata(_:_:_:).md)
- [AudioFileGetUserDataSize(_:_:_:_:)](audiotoolbox/audiofilegetuserdatasize(_:_:_:_:).md)
- [AudioFileGetUserDataSize64(_:_:_:_:)](audiotoolbox/audiofilegetuserdatasize64(_:_:_:_:).md)
- [AudioFileGetUserData(_:_:_:_:_:)](audiotoolbox/audiofilegetuserdata(_:_:_:_:_:).md)
- [AudioFileSetUserData(_:_:_:_:_:)](audiotoolbox/audiofilesetuserdata(_:_:_:_:_:).md)
- [AudioFileRemoveUserData(_:_:_:)](audiotoolbox/audiofileremoveuserdata(_:_:_:).md)