C / C++ / MFC

    class PointSorter
    {
    public:
      PointSorter()
      {
        points = NULL;
      }

      // !!! copy constructor called all the time during std::sort !!!
      PointSorter(const PointSorter& other)
      {
        points = other.points;
        printf("object copied");
      }

      PointSorter(std::vector<vl::fvec3 xmlns:vl="#unknown">* pvec==NULL)
      {
        points = pvec;
      }

      bool operator()(const unsigned int&a, const unsigned int&b)
      {
         return (*points)[a].z() < (*points)[b].z();
      }

      std::vector<vl::fvec3>* points;
    };
</vl::fvec3></vl::fvec3>

    PointSorter sorter(&mypoints);
    // std::vector<int> indices;
    std::sort( indices.begin(), indices.end(), sorter );
</int>