1 files changed, 1 insertions, 1 deletions
diff --git a/thread.c b/thread.c
index a1e405cda8..7fcbf9d67b 100644
--- a/thread.c
+++ b/thread.c
@@ -5402,7 +5402,7 @@ rb_thread_backtrace_locations_m(int argc, VALUE *argv, VALUE thval)
 }
 
 void
-Init_Thread_Mutex()
+Init_Thread_Mutex(void)
 {
     rb_thread_t *th = GET_THREAD();