Integer Pointers in SDL

SDL requires integer pointers in functions like SDL_GetWindowSize() to allow it to directly write the requested data back to your variables.

This is a common C-style approach for returning multiple values in functions that can’t use a direct return value due to limitations in C.

How It Works

When you call SDL_GetWindowSize(window, &width, &height), SDL writes the current window width and height into the memory locations pointed to by &width and &height.

This avoids the need for dynamic memory allocation or returning a struct. Here’s an example:

1#include <SDL.h>
2#include <iostream>
3
4int main() {
5  SDL_Init(SDL_INIT_VIDEO);
6
7  SDL_Window* window =
8    SDL_CreateWindow("Window Size Example",
9                     SDL_WINDOWPOS_CENTERED,
10                     SDL_WINDOWPOS_CENTERED,
11                     400, 400,
12                     SDL_WINDOW_RESIZABLE);
13
14  int width, height;
15  SDL_GetWindowSize(window, &width, &height);
16  std::cout << "Window size: " << width << "x"
17    << height << "\n";
18
19  SDL_DestroyWindow(window);
20  SDL_Quit();
21
22  return 0;
23}

1Window size: 400x400

Advantages

• Efficient: No temporary variables or heap allocations.
• Simple: Pointers allow multiple outputs in a single function call.

Caveats

Always ensure the pointers are valid. Passing nullptr for either dimension skips updating that value, which can lead to bugs if misused.

Using pointers keeps SDL lightweight and efficient, consistent with its design philosophy.