+ if (ret >= 0)
+ return 0;
+fail:
+ assert(ret < 0);
+ if (powd && powd->callback_btrn) {
+ AudioOutputUnitStop(powd->audio_unit);
+ AudioUnitUninitialize(powd->audio_unit);
+ CloseComponent(powd->audio_unit);
+ btr_remove_node(&powd->callback_btrn);
+ }