diff --git a/ChangeLog b/ChangeLog
index a8def61f71..30d91a0dbe 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Jan  2 14:33:12 2009  Tanaka Akira  <akr@fsij.org>
+
+	* ext/socket/mkconstants.rb (gen_int_to_name): don't compare constants
+	  in preprocessor because the constants may be enum.
+
 Fri Jan  2 14:11:07 2009  Tanaka Akira  <akr@fsij.org>
 
 	* ext/socket/mkconstants.rb (gen_int_to_name): add lenp argument.
diff --git a/ext/socket/mkconstants.rb b/ext/socket/mkconstants.rb
index 5b5b74105e..32b99d2fe3 100644
--- a/ext/socket/mkconstants.rb
+++ b/ext/socket/mkconstants.rb
@@ -104,19 +104,15 @@ def each_alias(pat)
 end
 
 ERB.new(<<'EOS', nil, '%').def_method(Object, "gen_int_to_name(int_var, lenp_var, pat)")
-    switch (<%=int_var%>) {
-%    each_alias(pat) {|names|
-%      names.each_with_index {|n, i|
-%      cond = ["defined(#{n})"]
-%      (0...i).each {|j| cond << "(!defined(#{names[j]}) || #{n} != #{names[j]})" }
-#if <%=cond.join(" && ")%>
-      case <%=n%>: if (<%=lenp_var%>) *<%=lenp_var%> = <%=n.bytesize%>; return <%=c_str n%>;
-#endif
-%      }
-%    }
-      default:
-        return NULL;
+% each_name(pat) {|n|
+#ifdef <%=n%>
+    if (<%=int_var%> == <%=n%>) {
+        if (<%=lenp_var%>) *<%=lenp_var%> = <%=n.bytesize%>;
+        return <%=c_str n%>;
     }
+#endif
+% }
+    return NULL;
 EOS
 
 result << ERB.new(<<'EOS', nil, '%').result(binding)