# AudioFileCountUserData(_:_:_:) Gets the number of user data items with a specified ID in a file. ``` func AudioFileCountUserData(_ inAudioFile: AudioFileID, _ inUserDataID: UInt32, _ outNumberItems: UnsafeMutablePointer) -> OSStatus ``` ## Parameters `inAudioFile` The audio file whose user data items are to be counted. `inUserDataID` The four-character code (such as `COMM`) of the user data item. `outNumberItems` On output, a pointer to the number of user data items of this type in the file. ## Return Value A result code if there’s an error (see Result Codes) or `noErr` if the operation succeeds. ## 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 --- 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)