I like that one too!

error: request for member ‘c_str’ in ‘iter. __gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = Heliostat**, _Container = std::vector<Heliostat*, std::allocator<Heliostat*> >]()->Heliostat::name()’, which is of non-class type ‘const char*’