diff --git a/ChangeLog b/ChangeLog
index 3b7611663b..3b6e667d66 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Oct 22 14:48:31 2006  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* signal.c (Init_signal): avoid duplicated installation of SIGCHLD
+	  handler.
+
 Sun Oct 22 16:47:56 2006  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* string.c (rb_str_substr): should be infected with only original
diff --git a/signal.c b/signal.c
index 2c0003520e..4b154b8301 100644
--- a/signal.c
+++ b/signal.c
@@ -968,10 +968,9 @@ Init_signal(void)
     install_sighandler(SIGPIPE, sigpipe);
 #endif
 
-#ifdef SIGCLD
+#if defined(SIGCLD)
     init_sigchld(SIGCLD);
-#endif
-#ifdef SIGCHLD
+#elif defined(SIGCHLD)
     init_sigchld(SIGCHLD);
 #endif