diff --git a/include/boost/function/function_base.hpp b/include/boost/function/function_base.hpp
index 9f4bd32..22f379f 100644
--- a/include/boost/function/function_base.hpp
+++ b/include/boost/function/function_base.hpp
@@ -295,44 +295,33 @@ namespace boost {
       };
 
 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
-
-#  if BOOST_WORKAROUND(__HP_aCC, <= 33900)
     template<bool cond, typename T> struct enable_if;
-#  else
-    template<bool, typename> struct enable_if;
-#  endif
-
     template<typename T> struct enable_if<true, T>  { typedef T type; };
     template<typename T> struct enable_if<false, T> {};
-#else
 
-#  if BOOST_WORKAROUND(__HP_aCC, <= 33900)
-      template<bool x>
-#  else
-      template<bool>
-#  endif
-      struct enabled
+    template<bool x>
+    struct enabled
+    {
+      template<typename T>
+      struct base
       {
-        template<typename T>
-        struct base
-        {
-          typedef T type;
-        };
+        typedef T type;
       };
+    };
 
-      template<>
-      struct enabled<false>
-      {
-        template<typename T>
-        struct base
-        {
-        };
-      };
-
-      template<bool Enabled, typename T>
-      struct enable_if : public enabled<Enabled>::template base<T>
+    template<>
+    struct enabled<false>
+    {
+      template<typename T>
+      struct base
       {
       };
+    };
+
+    template<bool Enabled, typename T>
+    struct enable_if : public enabled<Enabled>::template base<T>
+    {
+    };
 #endif
 
       // A type that is only used for comparisons against zero