diff --git a/include/boost/iostreams/detail/config/dyn_link.hpp b/include/boost/iostreams/detail/config/dyn_link.hpp
index 8b13293..41fb5d7 100644
--- a/include/boost/iostreams/detail/config/dyn_link.hpp
+++ b/include/boost/iostreams/detail/config/dyn_link.hpp
@@ -13,22 +13,33 @@
 
 #if defined(_MSC_VER)
 # pragma once
-#endif              
+#endif
 
 #include <boost/config.hpp>
 #include <boost/detail/workaround.hpp>
 
-//------------------Enable dynamic linking on windows-------------------------// 
+//------------------Enable dynamic linking on windows-------------------------//
+
 
-#ifdef BOOST_HAS_DECLSPEC 
+# if defined(BOOST_ALL_DYN_LINK) || defined(BOOST_IOSTREAMS_DYN_LINK)
+#  ifdef BOOST_IOSTREAMS_SOURCE
+#   define BOOST_IOSTREAMS_DECL BOOST_SYMBOL_EXPORT
+#  else
+#   define BOOST_IOSTREAMS_DECL BOOST_SYMBOL_IMPORT
+#  endif
+# endif
+
+/*
+#ifdef BOOST_HAS_DECLSPEC
 # if defined(BOOST_ALL_DYN_LINK) || defined(BOOST_IOSTREAMS_DYN_LINK)
 #  ifdef BOOST_IOSTREAMS_SOURCE
 #   define BOOST_IOSTREAMS_DECL __declspec(dllexport)
 #  else
 #   define BOOST_IOSTREAMS_DECL __declspec(dllimport)
-#  endif  
-# endif  
-#endif 
+#  endif
+# endif
+#endif
+*/
 
 #ifndef BOOST_IOSTREAMS_DECL
 # define BOOST_IOSTREAMS_DECL