hi in some cases i do assign values to variables just for the life of my function: void foo() { bool oldfoorunning = foorunning; foorunning = true; dojobs(); dofoooo(); foorunning = oldfoorunning; } now the problem arises when dojobs throws an exception. in order to be safe i have to do: void foo() { bool oldfoorunning = foorunning; foorunning = true; try { dojobs(); dofoooo(); } catch (...) { foorunning = oldfoorunning; throw; } foorunning = oldfoorunning; } this is ugly and it can get more ugly by having more than one such variable. then you stack try/catch into each other and code gets really ugly and error prone. for that reason i created a class as follows: template<class X> class protassign : public boost::non_copyable { public: inline protassign (X &var_, const X &newvalue) : var(var_) { oldvalue = var; var = newvalue; } inline ~protassign () { try { var = oldvalue; } CATCHDESTRUCTOR; //<-- my special destructor error catching macro, //forget it. (is there an alternative in boost?) } private: X &var; X oldvalue; }; now i can do: void foo() { protassign<bool> foorunning_assigner(foorunning, true); dojobs(); dofoooo(); } and that's all. is there one such thing in boost already??? cu erik -- Erik Thiele