diff --git a/winsup/cygwin/timer.cc b/winsup/cygwin/timer.cc
index 93e4714e2..657407fe4 100644
--- a/winsup/cygwin/timer.cc
+++ b/winsup/cygwin/timer.cc
@@ -692,7 +692,7 @@ ualarm (useconds_t value, useconds_t interval)
  return ret;
 }
 
-extern "C"
+extern "C" int
 timerfd_create (clockid_t clock_id, int flags)
 {
   int ret = -1;