---
title: "ExtAudioFileWrite(_:_:_:)"
framework: audiotoolbox
role: symbol
role_heading: Function
path: "audiotoolbox/extaudiofilewrite(_:_:_:)"
---

# ExtAudioFileWrite(_:_:_:)

Performs a synchronous, sequential write operation on an audio file.

## Declaration

```swift
func ExtAudioFileWrite(_ inExtAudioFile: ExtAudioFileRef, _ inNumberFrames: UInt32, _ ioData: UnsafePointer<AudioBufferList>) -> OSStatus
```

## Parameters

- `inExtAudioFile`: The extended audio file object that represents the file to write to.
- `inNumberFrames`: The number of frames to write.
- `ioData`: The buffer(s) from which audio data is written to the file.

## Return Value

Return Value A result code.

## Discussion

Discussion If the extended audio file object has an application data format, then the object’s converter converts the data in the ioData parameter to the file data format.

## See Also

### Reading and Writing Audio Data

- [ExtAudioFileRead(_:_:_:)](audiotoolbox/extaudiofileread(_:_:_:).md)
- [ExtAudioFileSeek(_:_:)](audiotoolbox/extaudiofileseek(_:_:).md)
- [ExtAudioFileTell(_:_:)](audiotoolbox/extaudiofiletell(_:_:).md)
- [ExtAudioFileWriteAsync(_:_:_:)](audiotoolbox/extaudiofilewriteasync(_:_:_:).md)