+ Music *m = unsmob_music (rv);
+ m->protect ();
+ return m;
+}
+
+
+MAKE_SCHEME_CALLBACK (Music, duration_length_callback, 1);
+SCM
+Music::duration_length_callback (SCM m)
+{
+ Music *me = unsmob_music (m);
+ Duration *d = unsmob_duration (me->get_property ("duration"));
+
+ Moment mom;
+ if (d)
+ {
+ mom = d->get_length ();
+ }
+ return mom.smobbed_copy ();