Ticket #6126: karma_numeric_int_hpp.patch

boost/spirit/home/karma/numeric/int.hpp

@@ -207 +207 @@
         template <typename OutputIterator, typename Attribute>
         static bool insert_int(OutputIterator& sink, Attribute const& attr)
         {
-            return sign_inserter::call(sink, traits::test_zero(attr)
-                      , traits::test_negative(attr), force_sign) &&
+            // For unknown reasons, the attr value is not passed
+            // correctly to traits::get_absolute_value() if it is not
+            // previously copied into a temporary variable. Seth
+            // Heeren <bugs at sehe.nl> et Jeroen Habraken
+            // <vexocide at gmail.com> from the Boost.Spirit general
+            // mailing list suspect a compiler error (which would be
+            // surprisingly present in g++ and clang++, but is not
+            // observed in MSVC) or a subtle case of undefined
+            // behavior in C++.
+            Attribute attr_copy(attr);
+            return sign_inserter::call(sink, traits::test_zero(attr_copy)
+                      , traits::test_negative(attr_copy), force_sign) &&
                    int_inserter<Radix, CharEncoding, Tag>::call(sink
-                      , traits::get_absolute_value(attr));
+                      , traits::get_absolute_value(attr_copy));
+            // // The original code without the workaround:
+            // return sign_inserter::call(sink, traits::test_zero(attr)
+            //           , traits::test_negative(attr), force_sign) &&
+            //        int_inserter<Radix, CharEncoding, Tag>::call(sink
+            //           , traits::get_absolute_value(attr));
         }
 
     public: