diff --git a/src/or/main.c b/src/or/main.c
index 3ccb6e9fc1..1c1c4774b4 100644
--- a/src/or/main.c
+++ b/src/or/main.c
@@ -2253,7 +2253,7 @@ run_main_loop_until_done(void)
 /** Libevent callback: invoked when we get a signal.
  */
 static void
-signal_callback(int fd, short events, void *arg)
+signal_callback(evutil_socket_t fd, short events, void *arg)
 {
   const int *sigptr = arg;
   const int sig = *sigptr;