diff --git a/include/boost/regex.hpp b/include/boost/regex.hpp
index 9cddec11..b07ca322 100644
--- a/include/boost/regex.hpp
+++ b/include/boost/regex.hpp
@@ -268,6 +268,7 @@ struct re_repeat : public re_jump
    int id;
    bool leading;
    bool greedy;
+   bool singleton;
 };