# AudioFileWriteBytes(_:_:_:_:_:) Writes bytes of audio data to an audio file. ``` func AudioFileWriteBytes(_ inAudioFile: AudioFileID, _ inUseCache: Bool, _ inStartingByte: Int64, _ ioNumBytes: UnsafeMutablePointer, _ inBuffer: UnsafeRawPointer) -> OSStatus ``` ## Parameters `inAudioFile` The audio file to which you want to write bytes of data. `inUseCache` Set to `true` if you want to cache the data. Otherwise, set to `false`. `inStartingByte` The byte offset where the audio data should be written. `ioNumBytes` On input, a pointer the number of bytes to write. On output, a pointer to the number of bytes actually written. `inBuffer` A pointer to a buffer containing the bytes to be written. ## Return Value A result code. See Result Codes. ## Discussion In most cases, you should use [`AudioFileWritePackets(_:_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioFileWritePackets(_:_:_:_:_:_:_:)) instead of this function. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)