diff --git a/pipewire-pulseaudio/src/mainloop.c b/pipewire-pulseaudio/src/mainloop.c
index 6198bd8c5..b363882e3 100644
--- a/pipewire-pulseaudio/src/mainloop.c
+++ b/pipewire-pulseaudio/src/mainloop.c
@@ -414,6 +414,7 @@ static void free_callback(pa_mainloop_api *m, pa_defer_event *e, void *userdata)
 }
 
 
+SPA_EXPORT
 void pa_mainloop_api_once(pa_mainloop_api* m, void (*callback)(pa_mainloop_api *m, void *userdata), void *userdata) {
 	struct once_info *i;
 	pa_defer_event *e;