Best way to return list of objects in C++

void DoSomething(const std::vector<SomeType>& in, std::vector<SomeType>& out)
  {
  ...
  // no need to return anything, just modify out
  }

void DoSomething(iterator const & from, iterator const & to);

std::vector theOutput(inputVector);

template <typename InIt, typename OutIt>
void DoMagic(InIt first, InIt last, OutIt out)
{
  for(; first != last; ++first) {
    if(IsCorrectIngredient(*first)) {
      *out = DoMoreMagic(*first);
      ++out;
    }
  }
}

std::vector<MagicIngredients> ingredients;
std::vector<MagicResults> result;

DoMagic(ingredients.begin(), ingredients.end(), std::back_inserter(results));

tuple<int, int, double> add_multiply_divide(int a, int b) {
  return make_tuple(a+b, a*b, double(a)/double(b));
}

list<int> foo(void)
{
    list<int> l;
    // do something
    return l;
}

list<int> lst=foo();

list<int> lst;
// do anything you want with list
lst.swap(foo());