Index: ./VC/boost_1_42_0/boost/iterator/counting_iterator.hpp
===================================================================
--- ./VC/boost_1_42_0/boost/iterator/counting_iterator.hpp	(old)
+++ ./VC/boost_1_42_0/boost/iterator/counting_iterator.hpp	(new)
@@ -108,7 +107,13 @@
                  // criterion (see boost/iterator/detail/facade_iterator_category.hpp)
 # endif 
         , traversal
-        , Incrementable const&                                    // reference
+        , Incrementable											// reference
+		// boost ticket #2640: counting_iterator::reference lifetime tied to iterator
+		// Counting_iterators must return copies because they only keep their current value in memory
+		// Otherwise the following doesn't work:
+		//		counting_iterator a;
+		//		counting_iterator b=a;
+		//		return *(--b);
+		// This will return a reference to the Incrementable member of local variable b. reverse_iterator does just that.
         , difference
       > type;
   };