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#include <memory>
#include <string>
#include <map>
 
template <typename> class manager;
 
template <typename T>
class managed_resource
{
        typedef std::shared_ptr<manager<T>> manager_ptr;
    public:
        managed_resource(manager_ptr const & parent)
            : parent_(parent)
        {
        }
 
        /* ... */
 
    private:
        manager_ptr parent_;
};
 
template <typename Policy>
class manager
    : Policy
    , std::enable_shared_from_this<manager<Policy>>
{
        typedef managed_resource<Policy> resource;
        typedef std::shared_ptr<resource> resource_ptr;
    public:
        resource_ptr get_resource(std::string const & name)
        {
            Policy & p = *this;
            if(p.find(name))
            {
                return p.get(name);
            }
            resource_ptr res = std::make_shared<resource>(this->shared_from_this());
            p.store(name, res);
            return res;
        }
};
 
class map_policy
{
        typedef std::shared_ptr<managed_resource<map_policy>> resource_ptr;
        typedef std::map<std::string, resource_ptr> resources;
 
    public:
        bool find(std::string const & name)
        {
            resources::iterator res_it = resources_.find(name);
            return res_it != resources_.end();
        }
 
        resource_ptr get(std::string const & name)
        {
            resources::iterator res_it = resources_.find(name);
            return res_it->second;
        }
 
        void store(std::string const & name, resource_ptr const & res)
        {
            resources_[name] = res;
        }
 
    private:
        resources resources_;
};
 
typedef manager<map_policy> my_manager;
 
int main()
{
    auto m = std::make_shared<my_manager>();
    auto res = m->get_resource("test");
    return 0;
}

In file included from /usr/include/c++/4.7/bits/shared_ptr.h:52:0,
                 from /usr/include/c++/4.7/memory:87,
                 from prog.cpp:1:
/usr/include/c++/4.7/bits/shared_ptr_base.h: In instantiation of ‘std::__shared_ptr<_Tp, _Lp>::__shared_ptr(std::_Sp_make_shared_tag, const _Alloc&, _Args&& ...) [with _Alloc = std::allocator<manager<map_policy> >; _Args = {}; _Tp = manager<map_policy>; __gnu_cxx::_Lock_policy _Lp = (__gnu_cxx::_Lock_policy)2u]’:
/usr/include/c++/4.7/bits/shared_ptr.h:317:64:   required from ‘std::shared_ptr<_Tp>::shared_ptr(std::_Sp_make_shared_tag, const _Alloc&, _Args&& ...) [with _Alloc = std::allocator<manager<map_policy> >; _Args = {}; _Tp = manager<map_policy>]’
/usr/include/c++/4.7/bits/shared_ptr.h:599:39:   required from ‘std::shared_ptr<_Tp> std::allocate_shared(const _Alloc&, _Args&& ...) [with _Tp = manager<map_policy>; _Alloc = std::allocator<manager<map_policy> >; _Args = {}]’
/usr/include/c++/4.7/bits/shared_ptr.h:615:42:   required from ‘std::shared_ptr<_Tp1> std::make_shared(_Args&& ...) [with _Tp = manager<map_policy>; _Args = {}]’
prog.cpp:75:43:   required from here
/usr/include/c++/4.7/bits/shared_ptr_base.h:1003:4: error: ‘std::enable_shared_from_this<manager<map_policy> >’ is an inaccessible base of ‘manager<map_policy>’

Standard output is empty