Correct Use of SDL_UpdateWindowSurface()

1#include <SDL.h>
2
3int main(int argc, char** argv) {
4  SDL_Init(SDL_INIT_VIDEO);
5  SDL_Window* window = SDL_CreateWindow(
6    "Update Example",
7    SDL_WINDOWPOS_UNDEFINED,
8    SDL_WINDOWPOS_UNDEFINED,
9    640, 480, 0);
10
11  SDL_Surface* surface = SDL_GetWindowSurface(
12    window);
13
14  while (true) {
15    // Render graphics to the surface here
16    SDL_FillRect(surface, NULL,
17      SDL_MapRGB(surface->format,
18        0x00, 0xFF, 0x00));  // Fill green
19
20    // Update the front buffer with what has
21    // been drawn on the back buffer
22    SDL_UpdateWindowSurface(window);
23  }
24
25  SDL_DestroyWindow(window);
26  SDL_Quit();
27  return 0;
28}