already defined in main.obj error C

Question

Hi I have a simple SDL application and I'm getting error that all variables in main.h are already defined. I don't see where I'm defining them twice.

main.h :

#pragma once
#include <stdio.h>
#include <SDL.h>
#include <SDL_image.h>

const char title[] = "game";

int windowWidth = 800;
int windowHeight = 600;

int isRunning = 0;

SDL_Window* window = NULL;

Uint32 render_flags = NULL;

SDL_Renderer* renderer = NULL;

main.c:

#include "textures.h"

int main() {

if (SDL_Init(SDL_INIT_EVERYTHING) == 0)
{
printf("SDL initialized successfully\n");
}
else
{
printf("SDL INIT ERROR");
SDL_Quit();
return -1;
}

window = SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, windowWidth, windowHeight, 0);

if (window)
{
printf("SDL Window created successfully\n");
}
else
{
printf("ERROR creating window");
SDL_DestroyWindow(window);
SDL_Quit();
return -1;
}

render_flags = SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC;
renderer = SDL_CreateRenderer(window, -1, render_flags);

if (renderer != 0)
{
printf("SDL Renderer created successfully\n");
}
else
{
printf("ERROR creating renderer");
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}

isRunning = 1;

// MAIN LOOP
SDL_RenderClear(renderer);

SDL_RenderCopy(renderer, tex, NULL, NULL);
SDL_RenderPresent(renderer);

SDL_Delay(5000);

// clean up resources before exiting
SDL_DestroyTexture(tex);
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);

return 0;
}

textures.h:

#include "main.h"
SDL_Surface* surface = NULL;
SDL_Texture* tex = NULL;
void LoadTextures();

textures.c:

#include "textures.h"

void LoadTextures() {

surface = IMG_Load("test.png");
tex = SDL_CreateTextureFromSurface(renderer, surface);
SDL_FreeSurface(surface);
}

Answer 1

In your .c file it should be
int windowWidth = 800;
That's with the int keyword before.
As with the new error, did you happen to declare renderer as an int variable by accident?

Answer 2

When you write
int windowWidth = 800;
This defines a new variable. You probably include this header in multiple .c files and this defines the variable multiple times.

Instead you should define the variable in a .c file and write
extern int windowWidth;
in the header file.

Answer 3

The Man I added extern before every variable in main.h for example I have only extern int windowWidth; and main.c I have only windowWidth = 800; now I'm getting error renderer int differs in levels of indirection from SDL_Renderer

Answer 4

The Man Thanks I finally got it working with extern word.