diff --git a/ChangeLog b/ChangeLog
index 0f4ab10d62..9bbf8c489d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Dec  5 14:33:41 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* signal.c (reserved_signal_p): static.
+
 Mon Dec  5 14:27:23 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* include/ruby/{subst.h,win32.h}, ext/socket/rubysocket.h: revert
diff --git a/signal.c b/signal.c
index 9b4e15eec0..09a77696a2 100644
--- a/signal.c
+++ b/signal.c
@@ -863,7 +863,8 @@ trap_ensure(struct trap_arg *arg)
 }
 #endif
 
-int reserved_signal_p(int signo)
+static int
+reserved_signal_p(int signo)
 {
 /* Synchronous signal can't deliver to main thread */
 #ifdef SIGSEGV