--- /usr/include/boost/any.hpp	2009-02-26 05:16:09.000000000 -0700
+++ any.hpp	2009-04-04 14:27:10.034162766 -0700
@@ -34,16 +34,18 @@
         any(const ValueType & value)
           : content(new holder<ValueType>(value))
         {
+            content->add_ref();
         }
 
         any(const any & other)
-          : content(other.content ? other.content->clone() : 0)
+          : content(other.content)
         {
+            if (content) content->add_ref();
         }
 
         ~any()
         {
-            delete content;
+            if (content) content->rem_ref();
         }
 
     public: // modifiers
@@ -99,6 +101,20 @@
 
             virtual placeholder * clone() const = 0;
 
+        public: // reference counting
+
+            long references;
+
+            void add_ref()
+            {
+                ++references;
+            }
+
+            void rem_ref()
+            {
+                if (--references == 0) delete this;
+            }
+
         };
 
         template<typename ValueType>
@@ -139,6 +155,18 @@
         template<typename ValueType>
         friend ValueType * unsafe_any_cast(any *);
 
+    private: // reference counting
+
+        void make_unique() const
+        {
+            if (content && content->references != 1) {
+                any* unconst = const_cast<any*>(this);
+                unconst->content->rem_ref();
+                unconst->content = unconst->content->clone();
+                unconst->content->add_ref();
+            }
+        }
+
 #else
 
     public: // representation (public so any_cast can be non-friend)
@@ -162,6 +190,7 @@
     template<typename ValueType>
     ValueType * any_cast(any * operand)
     {
+        operand->make_unique();
         return operand && operand->type() == typeid(ValueType)
                     ? &static_cast<any::holder<ValueType> *>(operand->content)->held
                     : 0;
@@ -170,6 +199,7 @@
     template<typename ValueType>
     const ValueType * any_cast(const any * operand)
     {
+        operand->make_unique();
         return any_cast<ValueType>(const_cast<any *>(operand));
     }
 
@@ -219,6 +249,7 @@
     template<typename ValueType>
     inline ValueType * unsafe_any_cast(any * operand)
     {
+        operand->make_unique();
         return &static_cast<any::holder<ValueType> *>(operand->content)->held;
     }