[C++11] Dedukcja parametru szablonu

#include <type_traits>
#include <memory>

template < typename T >
using shared_ptr_type = std::shared_ptr < T >;

template < class T, class U >
inline shared_ptr_type < T > shared_ptr_type_static_cast( const shared_ptr_type < U >& r )
{
    return std::static_pointer_cast < T >( r );
}

class A { };
class B
    : public A
{ };

int main() {
    shared_ptr_type < A > b( new B() );
    shared_ptr_type < B > c = shared_ptr_type_static_cast < B >( b );
}

shared_ptr_type < B > c = shared_ptr_type_static_cast < B, A >( b );

shared_ptr_type < B > c = shared_ptr_type_static_cast < B, shared_ptr_type < A > >( b );