Pointers as keys in map C++ STL

Question

I have a question on how pointers to a custom object are handled when used as Keys in an map. More specifically if I define

std::map< CustomClass*, int &         


        

Answer 1

Pointers will be handled but compared as pointers (memory order). You have to pass custom less functor if you wish to compare the objects:

template struct ptr_less {
    bool operator()(T* lhs, T* rhs) {
        return *lhs < *rhs; }};
map> mymap;