I was just thinking about writing a traditional music file player (such as the old FastTracker 2 file format) in SFML. I was looking for a way to trigger an event or some other type of hook when a sound finishes playing.
This would be useful because I need to implement a looping sample after a sample that is not looped is done playing in order for the instrument sound to be complete. Also, the .XM file format supports what is called "ping-pong" looping where the sound playback is reversed (negative frequency on some sound cards) at the beginning and end of a looping sample.
It may be possible to do some of this already using threads but I'm not that familiar with threading.