# AudioFileStreamGetProperty(_:_:_:_:) Retrieves the value of the specified property. ``` func AudioFileStreamGetProperty(_ inAudioFileStream: AudioFileStreamID, _ inPropertyID: AudioFileStreamPropertyID, _ ioPropertyDataSize: UnsafeMutablePointer, _ outPropertyData: UnsafeMutableRawPointer) -> OSStatus ``` ## Parameters `inAudioFileStream` The ID of the parser from which you wish to obtain data. The parser ID is returned by the [`AudioFileStreamOpen(_:_:_:_:_:)`](/documentation/AudioToolbox/AudioFileStreamOpen(_:_:_:_:_:)) function. `inPropertyID` A four-character ID indicating the audio file stream property whose value you want to read. See [Audio File Stream Properties](/documentation/AudioToolbox/1391506-audio-file-stream-properties) for possible values. `ioPropertyDataSize` On input, the size of the buffer in the `outPropertyData` parameter. Call the [`AudioFileStreamGetPropertyInfo(_:_:_:_:)`](/documentation/AudioToolbox/AudioFileStreamGetPropertyInfo(_:_:_:_:)) function to obtain the size of the property value. On output, the number of bytes of the property value returned. `outPropertyData` On output, the value of the specified property. ## Return Value A result code. See Result Codes. ## Discussion Some Core Audio property values are C types and others are Core Foundation objects. If you call this function to retrieve a value that is a Core Foundation object, then this function—despite the use of “Get” in its name—duplicates the object. You are responsible for releasing the object, as described in [The Create Rule](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html#//apple_ref/doc/uid/20001148-103029) in [Memory Management Programming Guide for Core Foundation](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/CFMemoryMgmt.html#//apple_ref/doc/uid/10000127i). ## See Also [`AudioFileStreamOpen(_:_:_:_:_:)`](/documentation/AudioToolbox/AudioFileStreamOpen(_:_:_:_:_:)) Creates and opens a new audio file stream parser. --- 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)