This post isn’t Chess related but it is still very nerdy. I have made 3 different SDL programs that all do the exact same thing. However they are written using different SDL versions over time as the API has changed. Therefore, SDL version 1,2, and 3 source code is provided as well as the commands to compile them!

SDL Version 1

#include <stdio.h>
#include <SDL.h>
int width=1280,height=720;
int loop=1;
SDL_Surface *surface;
SDL_Event e;
int main(int argc, char **argv)
{
 if(SDL_Init(SDL_INIT_EVERYTHING)){return 1;}

 SDL_putenv("SDL_VIDEO_WINDOW_POS=center");
 SDL_WM_SetCaption("SDL1 Program",NULL);
 surface=SDL_SetVideoMode(width,height,32,SDL_SWSURFACE);
 if(surface==NULL){return 1;}

 SDL_FillRect(surface,NULL,0xFF00FF);

 while(loop)
 {
  while(SDL_PollEvent(&e))
  {
   if(e.type==SDL_QUIT){loop=0;}
   if(e.type==SDL_KEYUP){if(e.key.keysym.sym==SDLK_ESCAPE){loop=0;}}
  }
  SDL_Flip(surface);
 }

 SDL_Quit();
 return 0;    
}

/*
SDL1 program that creates a window but nothing else.
Closes when user presses Esc or clicks the X of the window.
This is to test whether SDL1 programs can be compiled.

 With the sdl-config script:
 gcc -Wall -ansi -pedantic sdl1-test.c -o sdl1-test `sdl-config --cflags --libs` && ./sdl1-test

 Without the sdl-config script:
 gcc -Wall -ansi -pedantic sdl1-test.c -o sdl1-test -I/usr/include/SDL -D_GNU_SOURCE=1 -L/usr/lib/x86_64-linux-gnu -lSDL && ./sdl1-test
*/

SDL Version 2

#include <stdio.h>
#include <SDL.h>
int width=1280,height=720;
int loop=1;
SDL_Window *window;
SDL_Surface *surface;
SDL_Event e;
int main(int argc, char **argv)
{
 if(SDL_Init(SDL_INIT_VIDEO))
 {
  printf( "SDL could not initialize! SDL_Error: %s\n",SDL_GetError());return -1;
 }
 window=SDL_CreateWindow("SDL2 Program",SDL_WINDOWPOS_CENTERED,SDL_WINDOWPOS_CENTERED,width,height,SDL_WINDOW_SHOWN );
 if(window==NULL){printf( "Window could not be created! SDL_Error: %s\n", SDL_GetError() );return -1;}
 surface = SDL_GetWindowSurface( window ); /*get surface for this window*/
 SDL_FillRect(surface,NULL,0xFF00FF);
 SDL_UpdateWindowSurface(window);
 printf("SDL Program Compiled Correctly\n");
 while(loop)
 {
  while(SDL_PollEvent(&e))
  {
   if(e.type == SDL_QUIT){loop=0;}
   if(e.type == SDL_KEYUP)
   {
    if(e.key.keysym.sym==SDLK_ESCAPE){loop=0;}
   }
  }
 }
 SDL_DestroyWindow(window);
 SDL_Quit();
 return 0;
}

/*
 This source file is an example to be included in Chastity's Code Cookbook. This example follows the SDL version 2 which works differently than the most up to date version (version 3 at this time). There is also an updated version in the same repository that works with version 3.

 Linux Compile Command:

 With the sdl2-config script:
 gcc -Wall -ansi -pedantic sdl2-test.c -o sdl2-test `sdl2-config --cflags --libs` && ./sdl2-test

 Without the sdl2-config script:
 gcc -Wall -ansi -pedantic sdl2-test.c -o sdl2-test -I/usr/include/SDL2 -lSDL2 && ./sdl2-test
*/

SDL Version 3

#include <stdio.h>
#include <SDL.h>
int width=1280,height=720;
int loop=1;
SDL_Window *window;
SDL_Surface *surface;
SDL_Event e;
int main(int argc, char **argv)
{
 if(!SDL_Init(SDL_INIT_VIDEO))
 {
  printf( "SDL could not initialize! SDL_Error: %s\n",SDL_GetError());return -1;
 }
 window=SDL_CreateWindow("SDL3 Program",width,height,0);
 if(window==NULL){printf( "Window could not be created! SDL_Error: %s\n", SDL_GetError() );return -1;}
 surface = SDL_GetWindowSurface( window ); /*get surface for this window*/
 SDL_FillSurfaceRect(surface,NULL,0xFF00FF);
 SDL_UpdateWindowSurface(window);
 printf("SDL Program Compiled Correctly\n");
 while(loop)
 {
  while(SDL_PollEvent(&e))
  {
   if(e.type == SDL_EVENT_QUIT){loop=0;}
   if(e.type == SDL_EVENT_KEY_UP)
   {
    if(e.key.key==SDLK_ESCAPE){loop=0;}
   }
  }
 }
 SDL_DestroyWindow(window);
 SDL_Quit();
 return 0;
}

/*
 This source file is an example to be included in Chastity's Code Cookbook. By following the migration guide, I converted the SDL2-test program to the changes in SDL3.

 https://wiki.libsdl.org/SDL3/README-migration

 Windows Compile Command:

 gcc -Wall -ansi -pedantic sdl3-test.c -o sdl3-test -IC:/w64devkit/include/SDL3 -lSDL3 && sdl3-test

 Linux Compile Command:

 gcc -Wall -ansi -pedantic sdl3-test.c -o sdl3-test -I/usr/include/SDL3 -lSDL3 && ./sdl3-test

*/