struct d {cl_uint x;};
template <class T> struct Writer {
  virtual ~Writer() {}
  virtual void enqueue_write(T &data) = 0;
  virtual void close() = 0;
};
struct ParallelWriter : public Writer<std::unique_ptr<struct d>> {
  void enqueue_write(std::unique_ptr<struct d> &data) override {
    std::cout << "move into internal buffer, gets written somewhen. "
                 "Calculation can continuen";
  }
  void close() override { /* ... */ }
};
struct Calc {
  Calc(Writer<std::unique_ptr<struct d>> *writer) { m_writer = writer; }
  void run(int param) {
    std::cout << "allocate struct s, work on it w/ param, send to writern";
    auto data = std::make_unique<struct d>();
    data->x = static_cast<cl_uint>(2 * param);
    m_writer->enqueue_write(data);
  }
  void stop() {}
  Writer<std::unique_ptr<struct d>> *m_writer = nullptr;
};
int main() {
  auto writer = ParallelWriter{/*filename*/};
  auto calculation_object = Calc{&writer /*, options */};
  calculation_object.run(42);
  calculation_object.stop();
  writer.close();
}