diff --git a/include/boost/type_traits/function_traits.hpp b/include/boost/type_traits/function_traits.hpp
index 2112ce7..bfc3f7e 100644
--- a/include/boost/type_traits/function_traits.hpp
+++ b/include/boost/type_traits/function_traits.hpp
@@ -23,14 +23,14 @@ template<typename Function> struct function_traits_helper;
 template<typename R>
 struct function_traits_helper<R (*)(void)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 0);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 0);
   typedef R result_type;
 };
 
 template<typename R, typename T1>
 struct function_traits_helper<R (*)(T1)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 1);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 1);
   typedef R result_type;
   typedef T1 arg1_type;
   typedef T1 argument_type;
@@ -39,7 +39,7 @@ struct function_traits_helper<R (*)(T1)>
 template<typename R, typename T1, typename T2>
 struct function_traits_helper<R (*)(T1, T2)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 2);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 2);
   typedef R result_type;
   typedef T1 arg1_type;
   typedef T2 arg2_type;
@@ -50,7 +50,7 @@ struct function_traits_helper<R (*)(T1, T2)>
 template<typename R, typename T1, typename T2, typename T3>
 struct function_traits_helper<R (*)(T1, T2, T3)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 3);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 3);
   typedef R result_type;
   typedef T1 arg1_type;
   typedef T2 arg2_type;
@@ -60,7 +60,7 @@ struct function_traits_helper<R (*)(T1, T2, T3)>
 template<typename R, typename T1, typename T2, typename T3, typename T4>
 struct function_traits_helper<R (*)(T1, T2, T3, T4)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 4);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 4);
   typedef R result_type;
   typedef T1 arg1_type;
   typedef T2 arg2_type;
@@ -72,7 +72,7 @@ template<typename R, typename T1, typename T2, typename T3, typename T4,
          typename T5>
 struct function_traits_helper<R (*)(T1, T2, T3, T4, T5)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 5);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 5);
   typedef R result_type;
   typedef T1 arg1_type;
   typedef T2 arg2_type;
@@ -85,7 +85,7 @@ template<typename R, typename T1, typename T2, typename T3, typename T4,
          typename T5, typename T6>
 struct function_traits_helper<R (*)(T1, T2, T3, T4, T5, T6)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 6);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 6);
   typedef R result_type;
   typedef T1 arg1_type;
   typedef T2 arg2_type;
@@ -99,7 +99,7 @@ template<typename R, typename T1, typename T2, typename T3, typename T4,
          typename T5, typename T6, typename T7>
 struct function_traits_helper<R (*)(T1, T2, T3, T4, T5, T6, T7)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 7);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 7);
   typedef R result_type;
   typedef T1 arg1_type;
   typedef T2 arg2_type;
@@ -114,7 +114,7 @@ template<typename R, typename T1, typename T2, typename T3, typename T4,
          typename T5, typename T6, typename T7, typename T8>
 struct function_traits_helper<R (*)(T1, T2, T3, T4, T5, T6, T7, T8)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 8);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 8);
   typedef R result_type;
   typedef T1 arg1_type;
   typedef T2 arg2_type;
@@ -130,7 +130,7 @@ template<typename R, typename T1, typename T2, typename T3, typename T4,
          typename T5, typename T6, typename T7, typename T8, typename T9>
 struct function_traits_helper<R (*)(T1, T2, T3, T4, T5, T6, T7, T8, T9)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 9);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 9);
   typedef R result_type;
   typedef T1 arg1_type;
   typedef T2 arg2_type;
@@ -148,7 +148,7 @@ template<typename R, typename T1, typename T2, typename T3, typename T4,
          typename T10>
 struct function_traits_helper<R (*)(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10)>
 {
-  BOOST_STATIC_CONSTANT(int, arity = 10);
+  BOOST_STATIC_CONSTANT(unsigned, arity = 10);
   typedef R result_type;
   typedef T1 arg1_type;
   typedef T2 arg2_type;
@@ -174,7 +174,7 @@ struct function_traits :
 
 namespace detail {
 
-template<int N> 
+template<unsigned N> 
 struct type_of_size
 {
   char elements[N];
@@ -227,7 +227,7 @@ type_of_size<11> function_arity_helper(R (*f)(T1, T2, T3, T4, T5, T6, T7, T8,
 template<typename Function>
 struct function_traits
 {
-  BOOST_STATIC_CONSTANT(int, arity = (sizeof(detail::function_arity_helper((Function*)0))-1));
+  BOOST_STATIC_CONSTANT(unsigned, arity = (sizeof(detail::function_arity_helper((Function*)0))-1));
 };
 
 #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION