diff --git a/include/boost/exception/to_string_stub.hpp b/include/boost/exception/to_string_stub.hpp
index 493a30c..bfe330d 100644
--- a/include/boost/exception/to_string_stub.hpp
+++ b/include/boost/exception/to_string_stub.hpp
@@ -9,6 +9,7 @@
 #include <boost/exception/to_string.hpp>
 #include <iomanip>
 #include <typeinfo>
+#include <ios>
 
 namespace
 boost