Segmentation Fault in SDL_FillRect - c

Question

I'm using the SDL2 library, in C.
I made a test program to open a white window, but I get a segmentation fault with the function SDL_FillRect even though there are no errors or warnings when I build it.
Here's the code:
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_ttf.h>
static const int window_width = 1000;
static const int window_height = 1000;
int main(int argc, char* argv[])
{
//Window
SDL_Window *window = NULL;
//Window Surface where things will be shown
SDL_Surface *surface = NULL;
//Inicializar SDL
if(SDL_Init(SDL_INIT_VIDEO) == -1)
{
printf("Failed to initialize SDL2. SDL Error: %s", SDL_GetError());
}
else
{
window = SDL_CreateWindow("Test", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, window_width, window_height, SDL_WINDOW_SHOWN );
if(window == NULL)
printf("Failed to create SDL2 window. SDL Error: %s", SDL_GetError());
else
{
//Fill window with white color
SDL_FillRect(surface, NULL, SDL_MapRGB(surface->format, 0xFF, 0xFF, 0xFF));
//Update surface with new changes
SDL_UpdateWindowSurface(window);
//Wait before closing (parameter in miliseconds)
SDL_Delay(4000);
}
}
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}

Answer 1

You get Segmentation fault because surface is still NULL
This example code taken directly from the SDL wiki (https://wiki.libsdl.org/SDL_FillRect) shows how to create a SDL_Surface before calling SDL_FillRect()
/* Declaring the surface. */
SDL_Surface *s;
/* Creating the surface. */
s = SDL_CreateRGBSurface(0, width, height, 32, 0, 0, 0, 0);
/* Filling the surface with red color. */
SDL_FillRect(s, NULL, SDL_MapRGB(s->format, 255, 0, 0));