From: "Duane Murphy"

I am trying to make a member function call to all objects returned by an iterator. mem_fn is giving me an error when trying to call get_pointer() for a reference object. There is no overload for get_pointer of a reference object. Is there some reason or should I be doing this differently.

[...]

Here is some pseudo code to get things in the right orientation.

class obj { public: void method(); };

class obj_iterator { public: obj& iterator::operator*() const { return obj_; } };

class obj_container { public: obj_iterator begin(); obj_iterator end(); }

{ ... obj_container c; foreach( c.begin(), c.end(), mem_fn( method ) ); }

Your code works, when modified appropriately. mem_fn recognizes obj& references. The following modification, however, does not work (which might be your problem): #include #include <algorithm> class obj_base { public: void method(); }; class obj: public obj_base { }; class obj_iterator { public: obj& operator*() const; obj_iterator & operator++(); }; bool operator==(obj_iterator, obj_iterator); bool operator!=(obj_iterator, obj_iterator); class obj_container { public: obj_iterator begin(); obj_iterator end(); }; int main() { obj_container c; std::for_each( c.begin(), c.end(), boost::mem_fn( &obj::method ) ); } &obj::method is actually of type void (obj_base::*) (), and while mem_fn recognizes references to the 'base' type (obj_base&), it cannot tell whether obj& is a smart pointer or an object reference. I can probably fix this by using boost::is_convertible but unfortunately it's known to break some compilers. Food for thought. Thanks for the bug report. :-) -- Peter Dimov Multi Media Ltd.