diff --git a/include/boost/shared_ptr.hpp b/include/boost/shared_ptr.hpp
index bab848d..b1868fe 100644
--- a/include/boost/shared_ptr.hpp
+++ b/include/boost/shared_ptr.hpp
@@ -330,6 +330,19 @@ public:
         return px != 0;
     }
 
+#elif defined( _MANAGED )
+
+    static void unspecified_bool( this_type*** )
+    {
+    }
+
+    typedef void (*unspecified_bool_type)( this_type*** );
+
+    operator unspecified_bool_type() const // never throws
+    {
+        return px == 0? 0: unspecified_bool;
+    }
+
 #elif \
     ( defined(__MWERKS__) && BOOST_WORKAROUND(__MWERKS__, < 0x3200) ) || \
     ( defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ < 304) )