diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 410f4fc4817c..c752c222fc26 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,11 @@
+2007-04-10  Paolo Carlini  <pcarlini@suse.de>
+
+	* include/tr1/type_traits (__is_function_helper): New, uses
+	variadic templates.
+	(is_function): Forward to the latter.
+	* testsuite/tr1/4_metaprogramming/primary_type_categories/
+	is_function/is_function.cc: Add test.
+
 2007-04-10  Paolo Carlini  <pcarlini@suse.de>
 
 	PR libstdc++/28277 (partial: vstring bits)
diff --git a/libstdc++-v3/include/tr1/type_traits b/libstdc++-v3/include/tr1/type_traits
index c29701c8de0b..8645427c63ac 100644
--- a/libstdc++-v3/include/tr1/type_traits
+++ b/libstdc++-v3/include/tr1/type_traits
@@ -34,6 +34,8 @@
 #ifndef _TR1_TYPE_TRAITS
 #define _TR1_TYPE_TRAITS 1
 
+#pragma GCC system_header
+
 #include <bits/c++config.h>
 #include <tr1/type_traits_fwd.h>
 
@@ -171,14 +173,22 @@ _GLIBCXX_BEGIN_NAMESPACE(_GLIBCXX_TR1)
     : public integral_constant<bool, __is_class(_Tp)>
     { };
 
+  template<typename>
+    struct __is_function_helper
+    : public false_type { };
+
+  template<typename _Res, typename... _ArgTypes>
+    struct __is_function_helper<_Res(_ArgTypes...)>
+    : public true_type { };
+
+  template<typename _Res, typename... _ArgTypes>
+    struct __is_function_helper<_Res(_ArgTypes......)>
+    : public true_type { };
+
   template<typename _Tp>
     struct is_function
-    : public integral_constant<bool, !(is_void<_Tp>::value
-				       || is_scalar<_Tp>::value
-				       || is_array<_Tp>::value				       
-				       || is_reference<_Tp>::value
-				       || is_union<_Tp>::value
-				       || is_class<_Tp>::value)>
+    : public integral_constant<bool, (__is_function_helper<typename
+				      remove_cv<_Tp>::type>::value)>
     { };
 
   /// @brief  composite type traits [4.5.2].
diff --git a/libstdc++-v3/testsuite/tr1/4_metaprogramming/primary_type_categories/is_function/is_function.cc b/libstdc++-v3/testsuite/tr1/4_metaprogramming/primary_type_categories/is_function/is_function.cc
index a1e2317106ee..1ada9120b225 100644
--- a/libstdc++-v3/testsuite/tr1/4_metaprogramming/primary_type_categories/is_function/is_function.cc
+++ b/libstdc++-v3/testsuite/tr1/4_metaprogramming/primary_type_categories/is_function/is_function.cc
@@ -1,6 +1,6 @@
 // 2004-12-16  Paolo Carlini  <pcarlini@suse.de>
 //
-// Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+// Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
@@ -34,6 +34,7 @@ void test01()
   VERIFY( (test_category<is_function, int (int)>(true)) );
   VERIFY( (test_category<is_function, ClassType (ClassType)>(true)) );
   VERIFY( (test_category<is_function, float (int, float, int[], int&)>(true)) );
+  VERIFY( (test_category<is_function, int (int, ...)>(true)) );
 
   // Negative tests.
   VERIFY( (test_category<is_function, int&>(false)) );