diff --git a/test/algorithm/segmented_fold.cpp b/test/algorithm/segmented_fold.cpp
index d023cac8..cf3c6c16 100644
--- a/test/algorithm/segmented_fold.cpp
+++ b/test/algorithm/segmented_fold.cpp
@@ -5,6 +5,7 @@
     Distributed under the Boost Software License, Version 1.0. (See accompanying 
     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 ==============================================================================*/
+#include <string>
 #include <sstream>
 #include <iostream>
 #include <boost/detail/lightweight_test.hpp>