Draw a window example in C. Tested in arch with dwm and sdl2.

compile.sh

#!/bin/bash

# Check if sdl2 is installed
if [[ $(command -v sdl2-config) == "" ]]; then
	echo "Cant' find sdl2. Exiting..."
	exit 1;
fi

SDL_FLAGS=$(sdl2-config --cflags --libs)

if [[ $1 == "" ]]; then
	echo "No arguments. Please enter a file. Exiting..."
	exit 1;
fi

gcc -o output.o $1 $SDL_FLAGS

if [[ $2 == "comp" ]]; then
	echo "Compiled! Running..."
	./output.o
fi

sdl-window-test.c

#include <stdio.h>
#include "SDL.h"

#define WINDOW_W 300
#define WINDOW_H 300
#define RECT_SIZE 5

#define BACKGROUND_COLOR 20		// Will be used as rgb. Yes, only gray because I like it that way.

#define FPS 60
#define DELAY 0		// Add a custom delay in ms BETWEEN FRAMES

int main(int argc, char* argv[]) {
	int grid[WINDOW_H/RECT_SIZE][WINDOW_W/RECT_SIZE];
	
	// Clear the array
	for (int y = 0; y < WINDOW_H/RECT_SIZE; y++) {
		for (int x = 0; x < WINDOW_W/RECT_SIZE; x++) {
			grid[y][x] = 0;
		}
	}

	// Start SDL
	if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO) != 0) {
		SDL_Log("Unable to start: %s\n", SDL_GetError());
		return 1;
	}
	printf("SLD started!\n");
	
	// Create window
	SDL_Window* fuckwindows = SDL_CreateWindow("I am a test!", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, WINDOW_W, WINDOW_H, 0);  // Don't know the meaning of the 0
	if (!fuckwindows) {
		printf("Error creating a window: %s\n", SDL_GetError());
		SDL_Quit();
		return 1;
	}
	printf("Window created!\n");

	// Create renderer
	Uint32 render_flags = SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC;
	SDL_Renderer* fuckrenderers = SDL_CreateRenderer(fuckwindows, -1, render_flags);
	if (!fuckrenderers) {
		printf("Error creating a renderer: %s\n", SDL_GetError());
		SDL_DestroyWindow(fuckwindows);
		SDL_Quit();
		return 1;
	}
	printf("Renderer created!\n");

	// Main loop
	int running = 0, esc_pressed = 1;
	SDL_Event fuckevents;	// Create an event for the keys and shit
	while (running == 0) {
		// Events
		while (SDL_PollEvent(&fuckevents)) {
			switch (fuckevents.type) {
				// Window is closed?
				case SDL_QUIT:
					running = 1;
					break;
				case SDL_KEYDOWN:
					// Check the pressed key
					switch (fuckevents.key.keysym.scancode) {
						case SDL_SCANCODE_ESCAPE:
							esc_pressed = 0;
							printf("Esc key pressed!\n");
							break;
						default:
							break;
					}
					break;
				case SDL_KEYUP:
					// Check the released key
					switch (fuckevents.key.keysym.scancode) {
						case SDL_SCANCODE_ESCAPE:
							printf("Esc key released!\n");
							esc_pressed = 1;
							break;
						default:
							break;
					}
					break;
				default:
					break;
			}
		}
		
		if (esc_pressed == 0) {
			running = 1;	// Exit with esc
		}
		
		// Clear window
		SDL_SetRenderDrawColor(fuckrenderers, BACKGROUND_COLOR, BACKGROUND_COLOR, BACKGROUND_COLOR, 255);
		SDL_RenderClear(fuckrenderers);
		// Send to window
		SDL_RenderPresent(fuckrenderers);
		SDL_Delay(1000/FPS+DELAY);  // Divide 1000ms to the frames in one seccond to know the wait time + delay
	}

	// End of the program	
	printf("Reached end of the program!\n");
	SDL_DestroyRenderer(fuckrenderers);
	SDL_DestroyWindow(fuckwindows);
	SDL_Quit();

	return 0;
}