diff --git a/include/boost/system/detail/error_condition.hpp b/include/boost/system/detail/error_condition.hpp
index a7e35ab..b2da281 100644
--- a/include/boost/system/detail/error_condition.hpp
+++ b/include/boost/system/detail/error_condition.hpp
@@ -261,6 +261,58 @@ public:
         return !( lhs == rhs );
     }
 
+    //
+
+    template<class E, class N = typename detail::enable_if<std::is_error_condition_enum<E>::value>::type>
+    BOOST_SYSTEM_CONSTEXPR inline friend bool operator==( error_condition const & lhs, E rhs ) BOOST_NOEXCEPT
+    {
+        return lhs == make_error_condition( rhs );
+    }
+
+    template<class E, class N = typename detail::enable_if<std::is_error_condition_enum<E>::value>::type>
+    BOOST_SYSTEM_CONSTEXPR inline friend bool operator==( E lhs, error_condition const & rhs ) BOOST_NOEXCEPT
+    {
+        return make_error_condition( lhs ) == rhs;
+    }
+
+    template<class E, class N = typename detail::enable_if<std::is_error_condition_enum<E>::value>::type>
+    BOOST_SYSTEM_CONSTEXPR inline friend bool operator!=( error_condition const & lhs, E rhs ) BOOST_NOEXCEPT
+    {
+        return !( lhs == rhs );
+    }
+
+    template<class E, class N = typename detail::enable_if<std::is_error_condition_enum<E>::value>::type>
+    BOOST_SYSTEM_CONSTEXPR inline friend bool operator!=( E lhs, error_condition const & rhs ) BOOST_NOEXCEPT
+    {
+        return !( lhs == rhs );
+    }
+
+    //
+
+    template<class E, class N1 = void, class N2 = typename detail::enable_if<std::is_error_code_enum<E>::value>::type>
+    inline friend bool operator==( error_condition const & lhs, E rhs ) BOOST_NOEXCEPT
+    {
+        return lhs == make_error_code( rhs );
+    }
+
+    template<class E, class N1 = void, class N2 = typename detail::enable_if<std::is_error_code_enum<E>::value>::type>
+    inline friend bool operator==( E lhs, error_condition const & rhs ) BOOST_NOEXCEPT
+    {
+        return make_error_code( lhs ) == rhs;
+    }
+
+    template<class E, class N1 = void, class N2 = typename detail::enable_if<std::is_error_code_enum<E>::value>::type>
+    inline friend bool operator!=( error_condition const & lhs, E rhs ) BOOST_NOEXCEPT
+    {
+        return !( lhs == rhs );
+    }
+
+    template<class E, class N1 = void, class N2 = typename detail::enable_if<std::is_error_code_enum<E>::value>::type>
+    inline friend bool operator!=( E lhs, error_condition const & rhs ) BOOST_NOEXCEPT
+    {
+        return !( lhs == rhs );
+    }
+
 #endif
 
     std::string to_string() const
diff --git a/test/std_interop_test15.cpp b/test/std_interop_test15.cpp
index 87f64dc..66a953b 100644
--- a/test/std_interop_test15.cpp
+++ b/test/std_interop_test15.cpp
@@ -67,11 +67,11 @@ int main()
     BOOST_TEST_EQ( ec, enomem_n );
     BOOST_TEST_EQ( enomem_n, ec );
 
-    // BOOST_TEST_EQ( en, enomem_c );
-    // BOOST_TEST_EQ( enomem_c, en );
+    BOOST_TEST_EQ( en, enomem_c );
+    BOOST_TEST_EQ( enomem_c, en );
 
-    // BOOST_TEST_EQ( en, enomem_n );
-    // BOOST_TEST_EQ( enomem_n, en );
+    BOOST_TEST_EQ( en, enomem_n );
+    BOOST_TEST_EQ( enomem_n, en );
 
     return boost::report_errors();
 }