I'm new to boost::bind and boost::mem_fn. I've read the documentation and I think I understand what they do, but I'm not sure how to use them to accomplish my task. I have a class that contains several vectors in a map. I want to put a "foreach" method on the class that will callback an arbitrary member function, of an arbitrary class, for each item in the vector. I'm stuck on the signature of that method. A quick sketch of the structure: class VectorContent { public: void dosomething(); // there are bunches more, which is why I don't // want a foreach for every possible choice. }; class VectorHolder { std::map; std::vector<VectorContent>& rvectGet(const std::string& rksName); public: void foreach( const std::string& rksName, ); }; // the callback Caller::Bar( VectorContent& vc ) { vc.dosomething(); } I see two options for the caller: // option 1 Caller::Foo1() { VectorHolder callee; // in this case, foreach uses boost::mem_fn(), not me callee.foreach( "VectorName", &this::Bar ); } // option 2 Caller::Foo2(); { VectorHolder callee; callee.foreach( "VectorName", boost::mem_fn(&this::Bar) ); } In the case of option 1, all callers must share a common base class, which they do NOT, so that the signature of VectorHolder::foreach can be: typedef void (BaseClass::* MyCallBack)(VectorContent&); Leading to: void VectorHolder::foreach( const std::string& rsName, MyCallBack callback ) { std::vector<VectorContent>& rvect = rvectGet( rsName ); std::for_each( rvect.begin(), rvect.end(), boost::mem_fn(callback) ); } In the case of option 2, I have no idea what the signature should be. But the resulting method would be: void VectorHolder::foreach( std::string& rsName, WHAT? callback ) { std::vector<VectorContent>& rvect = rvectGet( rsName ); std::for_each( rvect.begin(), rvect.end(), callback ); } Grateful for any help, - Mark P.S. If there's an "option 3", I'm up for that, too.