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diff --git a/src/stlplus/persistence/persistent_smart_ptr.tpp b/src/stlplus/persistence/persistent_smart_ptr.tpp
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+////////////////////////////////////////////////////////////////////////////////
+
+//   Author:    Andy Rushton
+//   Copyright: (c) Southampton University 1999-2004
+//              (c) Andy Rushton           2004-2009
+//   License:   BSD License, see ../docs/license.html
+
+////////////////////////////////////////////////////////////////////////////////
+#include "persistent_int.hpp"
+#include "persistent_pointer.hpp"
+#include "persistent_callback.hpp"
+#include "persistent_interface.hpp"
+
+namespace stlplus
+{
+
+  ////////////////////////////////////////////////////////////////////////////////
+
+  template<typename  T, typename DE>
+  void dump_smart_ptr(dump_context& context, const smart_ptr<T>& data,
+                      DE dump_element)
+    throw(persistent_dump_failed)
+  {
+    // similar to the simple pointer routines, but use the address of the holder to tell which objects are aliases
+    // Many smart pointers can point to the same object.
+    // I could have used the address of the object to differentiate, 
+    // but that would not have differentiated between different null smart pointers
+    // so I use the address of the substructure to differentiate between different objects.
+    // get a magic key for the substructure - this also returns a flag saying whether its been seen before
+    std::pair<bool,unsigned> mapping = context.pointer_map(data._handle());
+    // dump the magic key
+    dump_unsigned(context,mapping.second);
+    // dump the contents but only if this is the first time this object has been seen
+    // use the existing routines for ordinary pointers to dump the contents
+    if (!mapping.first)
+      dump_pointer(context,data.pointer(),dump_element);
+  }
+
+  template<typename T, typename RE>
+  void restore_smart_ptr(restore_context& context, smart_ptr<T>& data,
+                         RE restore_element)
+    throw(persistent_restore_failed)
+  {
+    // get the old substructure magic key
+    unsigned magic = 0;
+    restore_unsigned(context,magic);
+    // lookup this magic number to see if we have seen this already
+    std::pair<bool,void*> mapping = context.pointer_map(magic);
+    if (mapping.first)
+    {
+      // this holder has already been restored
+      // dealias the existing holder and replace it with the seen-before holder to make this object an alias of it
+      data._make_alias((smart_ptr_holder<T>*)mapping.second);
+    }
+    else
+    {
+      // this is the first contact with this holder
+      // make sure this smart pointer is unique to prevent side-effects
+      data.clear_unique();
+      // map the magic key onto this structure's holder
+      // do this before restoring the object so that self-referential structures restore correctly
+      context.pointer_add(magic,data._handle());
+      // now restore the object
+      T* value = 0;
+      restore_pointer(context,value,restore_element);
+      data.set(value);
+    }
+  }
+
+  ////////////////////////////////////////////////////////////////////////////////
+  // smart_ptr_clone using callbacks
+
+  template<typename T>
+  void dump_smart_ptr_clone_callback(dump_context& context, const smart_ptr_clone<T>& data)
+    throw(persistent_dump_failed)
+  {
+    // similar to the simple pointer routines, but use the address of the holder to tell which objects are aliases
+    // Many smart pointers can point to the same object.
+    // I could have used the address of the object to differentiate, 
+    // but that would not have differentiated between different null smart pointers
+    // so I use the address of the substructure to differentiate between different objects.
+    // get a magic key for the substructure - this also returns a flag saying whether its been seen before
+    std::pair<bool,unsigned> mapping = context.pointer_map(data._handle());
+    // dump the magic key
+    dump_unsigned(context,mapping.second);
+    // dump the contents but only if this is the first time this object has been seen
+    // use the existing routines for ordinary pointers to dump the contents
+    if (!mapping.first)
+      dump_callback(context,data.pointer());
+  }
+
+  template<typename T>
+  void restore_smart_ptr_clone_callback(restore_context& context, smart_ptr_clone<T>& data)
+    throw(persistent_restore_failed)
+  {
+    // get the old substructure magic key
+    unsigned magic = 0;
+    restore_unsigned(context,magic);
+    // lookup this magic number to see if we have seen this already
+    std::pair<bool,void*> mapping = context.pointer_map(magic);
+    if (mapping.first)
+    {
+      // this holder has already been restored
+      // dealias the existing holder and replace it with the seen-before holder to make this object an alias of it
+      data._make_alias((smart_ptr_holder<T>*)mapping.second);
+    }
+    else
+    {
+      // this is the first contact with this holder
+      // make sure this smart pointer is unique to prevent side-effects
+      data.clear_unique();
+      // map the magic key onto this structure's holder
+      // do this before restoring the object so that self-referential structures restore correctly
+      context.pointer_add(magic,data._handle());
+      // now restore the object
+      T* value = 0;
+      restore_callback(context,value);
+      data.set(value);
+    }
+  }
+
+  ////////////////////////////////////////////////////////////////////////////////
+  // smart_ptr_clone using interface
+
+  template<typename T>
+  void dump_smart_ptr_clone_interface(dump_context& context, const smart_ptr_clone<T>& data)
+    throw(persistent_dump_failed)
+  {
+    // similar to the simple pointer routines, but use the address of the holder to tell which objects are aliases
+    // Many smart pointers can point to the same object.
+    // I could have used the address of the object to differentiate, 
+    // but that would not have differentiated between different null smart pointers
+    // so I use the address of the substructure to differentiate between different objects.
+    // get a magic key for the substructure - this also returns a flag saying whether its been seen before
+    std::pair<bool,unsigned> mapping = context.pointer_map(data._handle());
+    // dump the magic key
+    dump_unsigned(context,mapping.second);
+    // dump the contents but only if this is the first time this object has been seen
+    // use the existing routines for ordinary pointers to dump the contents
+    if (!mapping.first)
+      dump_interface(context,data.pointer());
+  }
+
+  template<typename T>
+  void restore_smart_ptr_clone_interface(restore_context& context, smart_ptr_clone<T>& data)
+    throw(persistent_restore_failed)
+  {
+    // get the old substructure magic key
+    unsigned magic = 0;
+    restore_unsigned(context,magic);
+    // lookup this magic number to see if we have seen this already
+    std::pair<bool,void*> mapping = context.pointer_map(magic);
+    if (mapping.first)
+    {
+      // this holder has already been restored
+      // dealias the existing holder and replace it with the seen-before holder to make this object an alias of it
+      data._make_alias((smart_ptr_holder<T>*)mapping.second);
+    }
+    else
+    {
+      // this is the first contact with this holder
+      // make sure this smart pointer is unique to prevent side-effects
+      data.clear_unique();
+      // map the magic key onto this structure's holder
+      // do this before restoring the object so that self-referential structures restore correctly
+      context.pointer_add(magic,data._handle());
+      // now restore the object
+      T* value = 0;
+      restore_interface(context,value);
+      data.set(value);
+    }
+  }
+
+  ////////////////////////////////////////////////////////////////////////////////
+
+} // end namespace stlplus