diff --git a/src/data/dv.hpp b/src/data/dv.hpp
index d6f95aa9..0eb27885 100644
--- a/src/data/dv.hpp
+++ b/src/data/dv.hpp
@@ -3,6 +3,7 @@
 #include <stdint.h>
 #include <string>
 #include <memory>
+#include <iosfwd>
 #include <vector>
 #include <cstring>
 #include <stdexcept>