A look at Win32::MediaPlayer's reveals it's a thin wrapper for mciSendString. mciSendString has limited capability for feedback. (It can be polled, but that's it.) It seems to work a lot like a remote control. A remote control doesn't know if a CD player is still playing the track the remote asked it to play or not. The CD player provides the feedback directly to the user.

I suggest you copy the contents of Win32::MediaPlayer — It doesn't have a C component — and play around. The status command might be useful.