diff --git a/include/boost/iostreams/copy.hpp b/include/boost/iostreams/copy.hpp
index 3579a9cd7..2284f7c44 100644
--- a/include/boost/iostreams/copy.hpp
+++ b/include/boost/iostreams/copy.hpp
@@ -159,7 +159,7 @@ class copy_operation {
                           is_direct<Source>(), is_direct<Sink>() );
     }
 private:
-    copy_operation& operator=(const copy_operation&);
+    BOOST_DELETED_FUNCTION(copy_operation& operator=(const copy_operation&));
     Source&          src_;
     Sink&            snk_;
     std::streamsize  buffer_size_;