---
title: "AudioFileGetUserDataSize(_:_:_:_:)"
framework: audiotoolbox
role: symbol
role_heading: Function
path: "audiotoolbox/audiofilegetuserdatasize(_:_:_:_:)"
---

# AudioFileGetUserDataSize(_:_:_:_:)

Gets the size of a user data item in an audio file.

## Declaration

```swift
func AudioFileGetUserDataSize(_ inAudioFile: AudioFileID, _ inUserDataID: UInt32, _ inIndex: UInt32, _ outUserDataSize: UnsafeMutablePointer<UInt32>) -> OSStatus
```

## Parameters

- `inAudioFile`: The audio file whose user data item size you want.
- `inUserDataID`: The four-character code of the designated user data item.
- `inIndex`: An index of the user data item with the four-character code specified in inUserDataID that you want to query.
- `outUserDataSize`: On output, if successful, the size of the user data item.

## Return Value

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

## Discussion

Discussion In this function, user data refers to: Chunks in AIFF, CAF, and WAVE files Resources in Sound Designer II files Other types of information in other files

## See Also

### Working with User Data

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