diff --git a/src/converter/registry.cpp b/src/converter/registry.cpp
index 88d96637..d247353c 100644
--- a/src/converter/registry.cpp
+++ b/src/converter/registry.cpp
@@ -39,35 +39,6 @@ namespace registry
   {
   }
 
-  namespace // <unnamed>
-  {
-    // A UnaryFunction type which deletes its argument
-    struct delete_item
-    {
-        template <class T>
-        void operator()(T* x) const
-        {
-            delete x;
-        }
-    };
-
-    // A UnaryFunction type which returns true iff its argument is a
-    // unwrapper which can convert the given Python object.
-    struct convertible
-    {
-        convertible(PyObject* p)
-            : m_p(p)
-        {}
-        
-        bool operator()(unwrapper_base* converter) const
-        {
-            return converter->convertible(m_p);
-        }
-        
-        PyObject* m_p;
-    };
-  }
-
   entry::~entry()
   {
       if (m_wrapper != 0)
@@ -79,12 +50,25 @@ namespace registry
       }
   }
 
-  unwrapper_base* entry::unwrapper(PyObject* p) const
+  std::pair<unwrapper_base*,void*>
+  entry::unwrapper(PyObject* p) const
   {
-      unwrappers::const_iterator q =
-          std::find_if(m_unwrappers.begin(), m_unwrappers.end(), convertible(p));
+      unwrapper_base* body = 0;
+      void* data = 0;
       
-      return q == m_unwrappers.end() ? 0 : *q;
+      for (unwrappers::const_iterator q = m_unwrappers.begin(),
+               finish = m_unwrappers.end();
+           q != finish;
+           ++q)
+      {
+          data = (*q)->can_convert(p);
+          if (data != 0)
+          {
+              body = *q;
+              break;
+          }
+      }
+      return std::make_pair(body,data);
   }
   
   wrapper_base* entry::wrapper() const
diff --git a/src/converter/unwrap.cpp b/src/converter/unwrap.cpp
index e0c09db6..33a7d7ae 100644
--- a/src/converter/unwrap.cpp
+++ b/src/converter/unwrap.cpp
@@ -13,7 +13,7 @@ namespace
   struct pyobject_unwrapper : unwrapper_base
   {
       pyobject_unwrapper();
-      bool convertible(PyObject*) const;
+      void* can_convert(PyObject*) const;
   };
   
   pyobject_unwrapper static_unwrapper;
@@ -23,13 +23,13 @@ namespace
   {
   }
       
-  bool pyobject_unwrapper::convertible(PyObject*) const
+  void* pyobject_unwrapper::can_convert(PyObject*) const
   {
-      return true;
+      return non_null;
   }
 }
 
-BOOST_PYTHON_EXPORT unwrapper_base*
-unwrap_more_<PyObject*>::m_unwrapper = &static_unwrapper;
+BOOST_PYTHON_DECL std::pair<unwrapper_base*,void*>
+unwrap_more_<PyObject*>::m_unwrapper(&static_unwrapper,&static_unwrapper);
 
 }}} // namespace boost::python::converter
diff --git a/src/converter/unwrapper.cpp b/src/converter/unwrapper.cpp
index 2b0adbd0..6279febf 100644
--- a/src/converter/unwrapper.cpp
+++ b/src/converter/unwrapper.cpp
@@ -21,4 +21,11 @@ unwrapper_base::~unwrapper_base()
         registry::remove(*this);
 }
 
+namespace
+{
+  int arbitrary;
+}
+
+void* const unwrapper_base::non_null = &arbitrary;
+
 }}} // namespace boost::python::converter