Access variable from one file from multiple files without copy-CodePudding

I'm trying to declare a variable in a header file Declarations.h which will be accessed from multiple files... like in C# it's a public static uint variableXXX then you can access it from everywhere.

Declarations.h:

#pragma once
#ifndef CLIENT_CONST_H
#define CLIENT_CONST_H

static DWORD LocalPlayerPointer, LocalPlayerAddress, battle_list = 0;

So the variables LocalPlayerPointer, LocalPlayerAddress are those who I want to be accessible from everywhere.

dllmain.cpp:

#include "Includes.h"

LocalPlayerPointer = (DWORD)((moduleBase   dwLocalPlayer));
LocalPlayerAddress = *(DWORD*)LocalPlayerPointer;
if (LocalPlayerAddress == 0) return;

Includes.h:

#include <Windows.h>
#include <iostream>
#include <cassert>
#include <vector>
#include <list>
#include <string>
#include <cstdint>
#include "Utils.h"
#include "Hook/Minhook/include/MinHook.h"
#include "ImGui/imgui.h"
#include "ImGui/imgui_impl_opengl3.h"
#include "ImGui/imgui_impl_win32.h"
#include "functions/functions.h"
#include "../Declarations.h"
#include "../Constants.h"
#include "../Offsets.h"
#include <chrono>
#include <sstream>
#include "../hooks.h"
#include "../targeting.h"

#pragma region OpenGL
#ifdef _WIN64
#define GWL_WNDPROC GWLP_WNDPROC
#endif

#define GLEW_STATIC
#if defined _M_X64
#include "Hook/GLx64/glew.h"
#pragma comment(lib, "Source/Hook/GLx64/glew32s.lib")
#elif defined _M_IX86
#include "Hook/GLx86/glew.h"
#pragma comment(lib, "Source/Hook/GLx86/glew32s.lib")
#endif
#include <gl/gl.h> 
#pragma comment(lib,"opengl32.lib")
#pragma endregion
extern LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
typedef BOOL(__stdcall* twglSwapBuffers) (_In_ HDC hDc);
typedef LRESULT(CALLBACK* WNDPROC)(HWND, UINT, WPARAM, LPARAM);

So, until here everything is fine. From dllmain.cpp I can access the variables LocalPlayerPointer, LocalPlayerAddress, battle_list and if I write to them, the values are reflected correctly.

The problem is when I try to read/write those variables from another file.

Let's put as example a new file called targeting.cpp.

targeting.h

#pragma once
#include "Source/Includes.h"

void Targeting();

targeting.cpp

#include "Source/Includes.h"

void Targeting(){
    std::cout << LocalPlayerPointer << std::endl;
    std::cout << LocalPlayerAddress << std::endl;
}

From targeting.cpp the std::cout displays 0.

What I'm doing wrong to access that variable like a public static var?

I want to access the same variable doesn't matters from which file I access to it.

EDIT:

After changing static DWORD LocalPlayerPointer, LocalPlayerAddress, battle_list = 0; to extern DWORD LocalPlayerPointer, LocalPlayerAddress, battle_list = 0; I'm getting this errors:

Error   LNK2001 unresolved external symbol "unsigned long LocalPlayerPointer" (?LocalPlayerPointer@@3KA)    Tibia OpenGL Imgui  C:\Users\Adrian\Documents\Tibia OpenGL Imgui\OpenGLTemplate\dllmain.obj 1   

Error   LNK2005 "unsigned long battle_list" (?battle_list@@3KA) already defined in hooks.obj    Tibia OpenGL Imgui  C:\Users\Adrian\Documents\Tibia OpenGL Imgui\OpenGLTemplate\dllmain.obj 1

Here is my hooks.h:

#pragma once
#include "Source/Includes.h"

void InitHooks();
extern DWORD BattleHookGateway;
extern DWORD __fastcall BattleHook(DWORD* pThis, DWORD battleList, DWORD localplayer);

My hooks.cpp:

#include "Source/Includes.h"

DWORD BattleHookGateway;

#pragma region InitHooks
void InitHooks() {
    // get battle list hook
    BattleHookGateway = (DWORD)TrampHook32((char*)BattleListHook, (char*)BattleHook, 5);
}
#pragma endregion

#pragma region Target
DWORD __fastcall BattleHook(DWORD* pThis, DWORD battleList, DWORD localplayer) {
    WriteLine("Hooked :D");
    DWORD battle_list = *(DWORD*)battleList;
    Targeting(battle_list);    
    return ((_BattleListHook)BattleHookGateway)(battleList, localplayer);
}
#pragma endregion

EDIT 2:

My problem now was that I was trying to declare them with = 0;

So after removing the inizialization in header file and init in another cpp file it worked.

CodePudding user response：

In the header file put

  extern DWORD battle_int;

in one C file put the definition

  DWORD battle_int = 0;

dont put 'static' thats specifically means 'private to this file'