SDL2 confusion with pointers c - c

Question

I'm trying to program a basic game with SDL2 library and I am getting a little bit confused with a basic concept.
Basically I would like to make a function:
void quit_clean (SDL_Window *window, SDL_Renderer *renderer)
{
if (renderer != NULL)
SDL_DestroyRenderer(renderer);
if (window != NULL)
SDL_DestroyWindow(window);
exit(EXIT_FAILURE);
}
I would call this function each time there is an error so I can free the renderer and the window properly before to quit the program
e.g.
texture = SDL_CreateTextureFromSurface(renderer, tmp);
if(texture==NULL){
printf ("SDL_CreateTextureFromSurface Error: : %s\n", SDL_GetError());
quit_clean (&window, &renderer);
}
Where I am getting confused is if I need to call this function from another function how does it work ?
To be precise I would have:
My main() function where I create my *window and my *renderer
a new my_function() called from main() in which I would among other stuffs create a texture from a surface and test errors
and finally my quit_clean() function called from my_function() in case of error.
The way I see it, in order to pass my window and my renderer from main() to quit_clean() using my_function() the prototypes would be then:
void my_function (SDL_Window **window, SDL_Renderer **renderer);
void quit_clean (SDL_Window ***window, SDL_Renderer ***renderer);
Am I correct or not?
If yes then how could I call this function from main() if needed.
If I call "quit_clean (&window, &renderer);" from my main() the types are not correct anymore then.
Or maybe I could create pointers from window and renderer and pass those pointers to quit_clean(). I don't know I'm confused, I'm not sure if my thought process is correct.
Do you have any tips for this kind of situation?

Answer 1

You don't need the double pointer as arguments to your functions:
int my_function (SDL_Window *window, SDL_Renderer *renderer);
int quit_clean (SDL_Window *window, SDL_Renderer *renderer);
As you might have noticed, i've added a return type (int), because every function should return a result, indicating success or failure.
Secondly, it would be better not to call the quit_clean function from other functions, instead, if you encounter an error in for e.g. my_function, return an error and call the quit_clean function in the main function.
Like this:
int main()
{
SDL_Window *window = NULL;
SDL_Renderer *renderer = NULL;
window = SDL_CreateWindow(...);
if (window) {
renderer = SDL_CreateRenderer(window, ...);
if (renderer) {
int err = my_function(window, renderer);
if (!err) { //success: 0, error: -1
//do what is needed to be done
}
}
}
//finally clean up,
//no matter the case (either due to error or program termination)
quit_clean(window, renderer);
return 0;
}
In the quit_clean function you have to check the passed arguments (although i think that SDL checks them too, but better than sorry):
int quit_clean (SDL_Window *window, SDL_Renderer *renderer)
{
//other cleanup first
//finally
if (renderer != NULL)
SDL_DestroyRenderer(renderer);
if (window != NULL)
SDL_DestroyWindow(window);
SDL_Quit();
}
And for clarity an example of my_function:
int my_function (SDL_Window *window, SDL_Renderer *renderer)
{
if (some_condition_does_not_hold)
return -1;
//do your stuff
//never call quit_clean if something goes wrong, return either -1 or
//some other (previously defined) negative error number
//finally
return 0; //success
}