diff --git a/io.hpp b/io.hpp
index a2126d25..1eca94e1 100644
--- a/io.hpp
+++ b/io.hpp
@@ -66,7 +66,7 @@ namespace util {
         typename IteratorB
     >
     util::view<IteratorA,IteratorB>
-    write (DstT &dst, const util::view<IteratorA, IteratorB> src)
+    write (DstT &&dst, const util::view<IteratorA, IteratorB> &src)
     {
         auto remain = src;
         while (!remain.empty ())