+/* Called from the main thread, from source.c only. The normal way to set the
+ * source output volume is to call pa_source_output_set_volume(), but the flat
+ * volume logic in source.c needs also a function that doesn't do all the extra
+ * stuff that pa_source_output_set_volume() does. This function simply sets
+ * o->volume and fires change notifications. */
+void pa_source_output_set_volume_direct(pa_source_output *o, const pa_cvolume *volume);
+