# MusicTrackGetProperty(_:_:_:_:) Gets a music track property value. ``` func MusicTrackGetProperty(_ inTrack: MusicTrack, _ inPropertyID: UInt32, _ outData: UnsafeMutableRawPointer, _ ioLength: UnsafeMutablePointer) -> OSStatus ``` ## Parameters `inTrack` The music track that you want to get a property value from. `inPropertyID` The identifier for the music track property that you want to get. See [Music Track Properties](/documentation/AudioToolbox/1515456-music-track-properties) for possible values. `outData` On output, the requested property value. `ioLength` On input, the available size for the retrieved property value. On output, the size of the valid property data that `outData` points to. ## Return Value A result code. ## Discussion Music track property values are always accessed by reference. As of OS X v10.6, all such property values are fixed length. This function’s main purpose is to retrieve a music track property value, but you also use it to obtain the size of a variable-length property. Do this, prior to retrieving a variable-length property value, to ensure that you allocate enough memory in `outData` to hold the value. To obtain a property value’s size, call this function with the `outData` parameter set to `NULL`. On output, the `ioLength` parameter contains the property size. --- 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)