diff --git a/src/pugixml.hpp b/src/pugixml.hpp
index ddfa4ad..b892db5 100644
--- a/src/pugixml.hpp
+++ b/src/pugixml.hpp
@@ -284,8 +284,8 @@ namespace pugi {
 		bool value;
 		operator bool() const { return value; }
 	};
-	static const boolean true_value{ true };
-	static const boolean false_value{ false };
+	static const boolean true_value(true);
+	static const boolean false_value(false);
 } // namespace pugi
 
 namespace pugi