Index: state_machine.hpp
===================================================================
--- state_machine.hpp	(revision 84739)
+++ state_machine.hpp	(working copy)
@@ -1732,15 +1732,21 @@
     template <class StateType,class EventType>
     HandledEnum do_process_helper(EventType const& evt, ::boost::mpl::false_ const &, bool is_direct_call)
     {
-        try
+        // when compiling without exception support there is no formal parameter "e" in the catch handler.
+        //  Declaring a local variable here does not hurt and will be "used" to make the code in the handler
+        // compilable although the code will never be executed.
+        std::exception e;
+        BOOST_TRY
         {
             return this->do_process_event(evt,is_direct_call);
         }
-        catch (std::exception& e)
+        BOOST_CATCH (std::exception& e)
         {
             // give a chance to the concrete state machine to handle
             this->exception_caught(evt,*this,e);
-        } 
+        }
+        BOOST_CATCH_END
+
         return HANDLED_FALSE;
     }
     // handling of deferred events