How to run SDL application in full screen mode 2 monitor

Question

C++ / C#

Hello.
I got someone else's project written in c++ SDL for revision. I have no experience with him. Therefore, I ask knowledgeable people to help. There is a machine with 2 monitors, ie. extended desktop. I need to make it so that the application opens on 2 monitors in full screen at startup.
Thank you for your time.

Answer 1

As it turned out, everything is outrageously simple. It is enough to create a window outside the current screen.

//Сначала получим параметры основного экрана.
SDL_DisplayMode current;
  for (int i = 0; i < SDL_GetNumVideoDisplays(); ++i){

    int should_be_zero = SDL_GetCurrentDisplayMode(i, &current);

    if (should_be_zero != 0)
      // In case of error...
      printf("Could not get display mode for video display #%d: %s", i, SDL_GetError());

    else
      // On success, print the current display mode.
      printf("Display #%d: current display mode is %dx%dpx @ %dhz. \n", i, current.w, current.h, current.refresh_rate);

  }

//Создадим окно со следующими параметрами левого верхнего угла  current.w + 1, current.h + 1
  m_window = SDL_CreateWindow("SDL Window",
    current.w + 1,
    current.h + 1,
    1152, 648,
#ifdef NDEBUG
    SDL_WINDOW_FULLSCREEN_DESKTOP |
#endif
    SDL_WINDOW_OPENGL);