diff --git a/ChangeLog b/ChangeLog
index 5368a48e4b..6dc259ff7f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Apr  9 00:28:40 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/socket/constants.c (rsock_cmsg_type_arg): fix macro name.
+
 Mon Apr  8 23:57:21 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* object.c (id_for_setter): extract common code from const, class
diff --git a/ext/socket/constants.c b/ext/socket/constants.c
index 39f985b316..bab27b23bb 100644
--- a/ext/socket/constants.c
+++ b/ext/socket/constants.c
@@ -105,7 +105,7 @@ rsock_cmsg_type_arg(int family, int level, VALUE type)
             return constant_arg(type, rsock_scm_optname_to_int, "unknown UNIX control message");
           case IPPROTO_IP:
             return constant_arg(type, rsock_ip_optname_to_int, "unknown IP control message");
-#ifdef INET6
+#ifdef IPPROTO_IPV6
           case IPPROTO_IPV6:
             return constant_arg(type, rsock_ipv6_optname_to_int, "unknown IPv6 control message");
 #endif