diff --git a/ChangeLog b/ChangeLog
index e22739c077..447dca2056 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Jan  1 16:08:11 2009  Tanaka Akira  <akr@fsij.org>
+
+	* ext/socket/mkconstants.rb: generate init_constants function.
+
+	* ext/socket/socket.c (Init_socket): call init_constants.
+
 Thu Jan  1 16:03:04 2009  Tanaka Akira  <akr@fsij.org>
 
 	* ext/socket/mkconstants.rb (Socket::AF_INET6): moved from socket.c.
diff --git a/ext/socket/mkconstants.rb b/ext/socket/mkconstants.rb
index 02d7e17b77..257b315c19 100644
--- a/ext/socket/mkconstants.rb
+++ b/ext/socket/mkconstants.rb
@@ -53,6 +53,9 @@ def each_data
 end
 
 result << ERB.new(<<'EOS', nil, '%').result(binding)
+static void
+init_constants(VALUE mConst)
+{
 % each_data {|guard, define, name, default_value|
 %   if guard
 #if <%=guard%>
@@ -69,6 +72,7 @@ result << ERB.new(<<'EOS', nil, '%').result(binding)
 %   end
 
 % }
+}
 EOS
 
 if opt_o
diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index b91e1396cd..fe972ce5f7 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -3592,6 +3592,8 @@ sock_define_uconst(const char *name, unsigned int value, VALUE mConst)
 #define sock_define_const(name, value) sock_define_const(name, value, mConst)
 #define sock_define_uconst(name, value) sock_define_uconst(name, value, mConst)
 
+#include "constants.h"
+
 /*
  * Class +Socket+ provides access to the underlying operating system
  * socket implementations. It can be used to provide more operating system
@@ -3732,5 +3734,5 @@ Init_socket()
 
     /* constants */
     mConst = rb_define_module_under(rb_cSocket, "Constants");
-#include "constants.h"
+    init_constants(mConst);
 }