--- skip.hpp.orig	2007-03-20 16:20:55.253000000 -0400
+++ skip.hpp	2007-03-20 16:11:51.096750000 -0400
@@ -67,7 +67,17 @@
 void skip(Device& dev, stream_offset off)
 { 
     typedef typename mode_of<Device>::type mode;
-    detail::skip(dev, off, is_convertible<mode, seekable>());
+    typedef mpl::or_<
+        mpl::and_<
+            is_convertible<mode, input>,
+            is_convertible<mode, input_seekable>
+        >,
+        mpl::and_<
+            is_convertible<mode, output>,
+            is_convertible<mode, output_seekable>
+        >
+    > can_seek;
+    detail::skip(dev, off, can_seek());
 }
 
 template<typename Filter, typename Device>