Re: [Boost-users] Returning a shared_ptr or raw pointer from a template function

31 Mar 2009

      AMDG

Ryan McConnehey wrote:
...
I would like to have a class that has this create function and upon 
creation of the class specify if the create function returns a raw 
pointer or shared_ptr.
template <class U>  //The U specifies is the create function returns a 
raw or shared pointer
class Rdi
{
template <class S>
U create(void)
{
  U temp(new S());
  return temp;
}
};
How would I modify this class to allow the user to make the following 
calls?
Rdi<boost::shared_ptr> fun1;
This won't compile because boost::shared_ptr is a class template.
...
Tm* tm3 = fun1.create<Tm>();
Rdi<raw Pointer???> fun2;
boost::shared_ptr<Tm> tm4 = fun2.create<Tm>();
Any help would be appreciated.
Try

#include <boost/mpl/apply.hpp>
#include <boost/type_traits/add_pointer.hpp>
#include <boost/shared_ptr.hpp>

template<class U>
class Rdi {
    typedef typename boost::mpl::apply<U, Rdi>::type ptr_type;
    template<class S>
    ptr_type create();
};

Rdi<boost::shared_ptr<boost::mpl::_1> > fun1;
Rdi<boost::add_pointer<boost::mpl::_1> > fun2;

In Christ,
Steven Watanabe