1 files changed, 11 insertions, 2 deletions
diff --git a/boost/program_options/variables_map.hpp b/boost/program_options/variables_map.hpp
index 9621e05245..be0a4b64e3 100644
--- a/boost/program_options/variables_map.hpp
+++ b/boost/program_options/variables_map.hpp
@@ -153,6 +153,9 @@ namespace boost { namespace program_options {
         // Resolve conflict between inherited operators.
         const variable_value& operator[](const std::string& name) const
         { return abstract_variables_map::operator[](name); }
+
+        // Override to clear some extra fields.
+        void clear(); 
         
         void notify();
 
@@ -171,8 +174,10 @@ namespace boost { namespace program_options {
                           bool utf8);
         
         /** Names of required options, filled by parser which has
-            access to options_description. */
-        std::set<std::string> m_required;
+            access to options_description.
+            The map values are the "canonical" names for each corresponding option.
+            This is useful in creating diagnostic messages when the option is absent. */
+        std::map<std::string, std::string> m_required;
     };
 
 
@@ -208,4 +213,8 @@ namespace boost { namespace program_options {
 
 }}
 
+#if defined(BOOST_MSVC)
+#   pragma warning (pop)
+#endif
+
 #endif