diff --git a/ubi/watch.cpp b/ubi/watch.cpp
index 9cbed5d..1b68fd1 100644
--- a/ubi/watch.cpp
+++ b/ubi/watch.cpp
@@ -65,8 +65,7 @@
     }
 }
 
-int Watch::callback(sd_event_source* s, int fd, uint32_t revents,
-                    void* userdata)
+int Watch::callback(sd_event_source*, int fd, uint32_t revents, void* userdata)
 {
     if (!(revents & EPOLLIN))
     {