c++ unresolved external symbol when trying to compile program [duplicate] - c++

Question

This question already has answers here:
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 9 years ago.
When trying to compile my program this error shows up:
Error 1 error LNK2001: unresolved external symbol "public: static class sf::Texture TextureManager::texture" (?texture#TextureManager##2VTexture#sf##A)
This is my code:
main.cpp:
int main()
{
TextureManager::Initialize();
}
TextureManager.h:
#include <SFML\Graphics.hpp>
using namespace sf;
class TextureManager
{
public:
static Texture texture;
public:
static void Initialize();
};
TextureManager.cpp:
#include <SFML\Graphics.hpp>
#include <iostream>
#include "TextureManager.h"
using namespace sf;
void TextureManager::Initialize()
{
if(!texture.loadFromFile("Textures\\Blocks\\Texture.png"))
{
std::cout << "Error!";
}
else
{
std::cout << "Sucess!";
}
}
I've tried searching for any solutions (including this site) but have not found any.

Answer 1

When you have a static member in C++, you should define it in your .cpp :
static Texture Texture::texture;
This is because static members must be defined in exactly one translation unit, in order to not violate the One-Definition Rule.
You can do it at the top of your TextureManager.cpp:
#include <SFML\Graphics.hpp>
#include <iostream>
#include "TextureManager.h"
using namespace sf;
static Texture Texture::texture; // <-
void TextureManager::Initialize()
{
}