diff --git a/common/JackControlAPI.h b/common/JackControlAPI.h
index 520b3321..0289e11d 100644
--- a/common/JackControlAPI.h
+++ b/common/JackControlAPI.h
@@ -76,7 +76,7 @@ jackctl_wait_signals(
 
 SERVER_EXPORT void
 jackctl_finish_signals(
-    void);
+    jackctl_sigmask_t * signals);
 
 SERVER_EXPORT jackctl_server_t *
 jackctl_server_create(