audio-play! returns the file id.

The file id is now a randomized number

audio-player.rkt

@@ -143,6 +143,8 @@
                               (set-audio-play-state! handle (evt-data e))
                               (cb-state* (evt-data e)))
                              ((is-event? e 'audio-done) (cb-eof*))
+                             ((is-event? e 'exception)
+                              (err-sound "audio-player: exception event: ~a" e))
                              (else (warn-sound "audio-player: unknown event ~a" e))
                              )
                        (loop))
@@ -175,8 +177,11 @@
   )
 
 (define/contract (audio-play! handle audio-file)
-  (->  audio-play? path-string? symbol?)
-  ((audio-play-rpc handle) 'open audio-file))
+  (->  audio-play? path-string? number?)
+  (let ((result ((audio-play-rpc handle) 'open audio-file)))
+    (when (eq? result 'error)
+        (error "Got an error from the placed audio player"))
+    (cadr result)))
 
 (define/contract (audio-pause! handle paused)
   (-> audio-play? boolean? symbol?)