Positions a music event iterator at the previous event on a music track.
- iOS 5.0+
- macOS 10.0+
- UIKit for Mac 13.0+Beta
- tvOS 9.0+
The music event iterator to reposition.
A result code.
Use this function to decrement a music event iterator, moving it backward through a music track’s events.
If an iterator is at the first event of a track when you call this function, the iterator position remains unchanged and this function returns an error.
The following code snippet illustrates how to use a music event iterator to proceed backward along a music track, from the end: