=== modified file 'pmt/src/lib/pmt.cc'
--- pmt/src/lib/pmt.cc	2009-01-30 14:40:12 +0000
+++ pmt/src/lib/pmt.cc	2009-01-30 14:41:35 +0000
@@ -54,6 +54,8 @@
 
 #endif
 
+void intrusive_ptr_add_ref(pmt_base* p) { ++(p->count_); }
+void intrusive_ptr_release(pmt_base* p) { if (--(p->count_) == 0 ) delete p; }
 
 pmt_base::~pmt_base()
 {

=== modified file 'pmt/src/lib/pmt.h'
--- pmt/src/lib/pmt.h	2009-01-30 14:40:12 +0000
+++ pmt/src/lib/pmt.h	2009-01-30 14:41:35 +0000
@@ -23,7 +23,7 @@
 #ifndef INCLUDED_PMT_H
 #define INCLUDED_PMT_H
 
-#include <boost/shared_ptr.hpp>
+#include <boost/intrusive_ptr.hpp>
 #include <boost/any.hpp>
 #include <complex>
 #include <string>
@@ -48,8 +48,10 @@
  * \brief typedef for shared pointer (transparent reference counting).
  * See http://www.boost.org/libs/smart_ptr/smart_ptr.htm
  */
-typedef boost::shared_ptr<pmt_base> pmt_t;
+typedef boost::intrusive_ptr<pmt_base> pmt_t;
 
+extern void intrusive_ptr_add_ref(pmt_base*);
+extern void intrusive_ptr_release(pmt_base*);
 
 class pmt_exception : public std::logic_error
 {

=== modified file 'pmt/src/lib/pmt_int.h'
--- pmt/src/lib/pmt_int.h	2009-01-30 14:40:12 +0000
+++ pmt/src/lib/pmt_int.h	2009-01-30 14:41:35 +0000
@@ -34,8 +34,10 @@
 #define PMT_LOCAL_ALLOCATOR 0		// define to 0 or 1
 
 class pmt_base : boost::noncopyable {
+  mutable boost::detail::atomic_count count_;
+
 protected:
-  pmt_base(){};
+  pmt_base() : count_(0) {};
   virtual ~pmt_base();
 
 public:
@@ -65,6 +67,9 @@
   virtual bool is_c32vector() const { return false; }
   virtual bool is_c64vector() const { return false; }
 
+  friend void intrusive_ptr_add_ref(pmt_base* p);
+  friend void intrusive_ptr_release(pmt_base* p);
+
 # if (PMT_LOCAL_ALLOCATOR)
   void *operator new(size_t);
   void operator delete(void *, size_t);