Unresolved External Symbol- Error in guide? - c++

So I've been trying to fix a weird bug in a game engine SDK where the Windows loading cursor is used instead of the game's own cursor.
The fix for this is here: http://www.crydev.net/wiki/index.php/Use_Custom_Cursor#Step_1:_Fixing_The_Cursor_Bug.
I have followed the fix, but I keep getting these when building the game DLL:
Error 1 error LNK2019: unresolved external symbol "public: __thiscall MODCursor::MODCursor(void)" (??0MODCursor##QAE#XZ) referenced in function "public: __thiscall CGame::CGame(void)" (??0CGame##QAE#XZ) C:\Users\User\Desktop\Crytek\Mods\CryEngine2\Code\Game.obj GameDll
Error 2 error LNK2019: unresolved external symbol "public: __thiscall MODCursor::~MODCursor(void)" (??1MODCursor##QAE#XZ) referenced in function "public: virtual __thiscall CGame::~CGame(void)" (??1CGame##UAE#XZ) C:\Users\User\Desktop\Crytek\Mods\CryEngine2\Code\Game.obj GameDll
Yeah, normally I can fix this issue quite easily by defining the class properly, but it hasn't worked in this case. What can I be doing wrong?
The files are as they are in the guide for the fix, so there isn't really any point in posting the files here since they would be a waste of space on here. If the files are really needed to investigate this issue, I'll upload them if anyone requests them.
Perhaps there's an error within the fix itself? One possible difference from the fix to my build is that the fix is using Visual Studio 2008, I am using Visual Studio 2013.

Maybe try to put it all inside .h file:
#ifndef _MOD_CURSOR
#define _MOD_CURSOR
#include <windows.h>
#include "resource.h"
#undef GetUserName // This is a macro in windows.h, gives issues with GetUserName() of ISystem
class MODCursor : public ISystemEventListener
{
public:
MODCursor() {
gEnv->pSystem->GetISystemEventDispatcher()->RegisterListener(this);
m_cursor = LoadCursor((HINSTANCE)g_hInst, MAKEINTRESOURCE(IDC_CURSOR1));
SetCursor(m_cursor);
}
~MODCursor(){
gEnv->pSystem->GetISystemEventDispatcher()->RemoveListener(this);
}
private:
virtual void OnSystemEvent( ESystemEvent event,UINT_PTR wparam,UINT_PTR lparam ) {
if(event == ESYSTEM_EVENT_TOGGLE_FULLSCREEN || event == ESYSTEM_EVENT_RESIZE || event == ESYSTEM_EVENT_CHANGE_FOCUS){
if (m_cursor != GetCursor())
SetCursor(m_cursor);
}
}
HCURSOR m_cursor;
};
#endif

Related

Errors LNK 2019 and LNK2028 for one function in a class, other works fine

I normally work in c# and am out of my wits for this one . I used Walkthrough: Creating and Using a Dynamic Link Library (C++) to create a Dynamic Link Library.
I have defined two methods as shown below
DeveloperConsoleManager.h
#pragma once
#include "atlstr.h"
#ifdef DEVCONSOLEMANAGER_EXPORTS
#define DEVCONSOLEMANAGER_API __declspec(dllexport)
#else
#define DEVCONSOLEMANAGER_API __declspec(dllimport)
#endif
namespace DeveloperConsoleManager
{
class DeveloperConsoleLogic
{
public:
// Returns a + b
static DEVCONSOLEMANAGER_API double Add(double a, double b);
static DEVCONSOLEMANAGER_API bool CheckforValidFile(CString fileName);
};
}
DeveloperConsoleManager.cpp
// DeveloperConsoleManager.cpp : Defines the exported functions for the DLL application.
//
#include "stdafx.h"
#include "DeveloperConsoleManager.h"
namespace DeveloperConsoleManager
{
double DeveloperConsoleLogic::Add(double a, double b)
{
return a + b;
}
bool DeveloperConsoleLogic :: CheckforValidFile(CString fileName)
{
return false;
}
}
I use these methods in a .cpp file in a different project (type: Application (.exe)). When I Build the solution, there are following linker errors
Warning 1 warning C4273: 'DeveloperConsoleManager::DeveloperConsoleLogic::Add' : inconsistent dll linkage e:\md_69\developerconsolemanager\developerconsolemanager.cpp 10
Warning 2 warning C4273: 'DeveloperConsoleManager::DeveloperConsoleLogic::CheckforValidFile' : inconsistent dll linkage e:\md_69\developerconsolemanager\developerconsolemanager.cpp 16
Error 3 error LNK2028: unresolved token (0A0004F1) "public: static bool __cdecl DeveloperConsoleManager::DeveloperConsoleLogic::CheckforValidFile(class ATL::CStringT > >)" (?CheckforValidFile#DeveloperConsoleLogic#DeveloperConsoleManager##$$FSA_NV?$CStringT#_WV?$StrTraitMFC_DLL#_WV?$ChTraitsCRT#_W#ATL#####ATL###Z) referenced in function "public: void __thiscall CSaSsiConsoleUi::UploadSsiCheck(void)" (?UploadSsiCheck#CSaSsiConsoleUi##$$FQAEXXZ) E:\MD_69\DeveloperConsoleUI\SaSsiConsoleUI.obj
Error 4 error LNK2019: unresolved external symbol "public: static bool __cdecl DeveloperConsoleManager::DeveloperConsoleLogic::CheckforValidFile(class ATL::CStringT > >)" (?CheckforValidFile#DeveloperConsoleLogic#DeveloperConsoleManager##$$FSA_NV?$CStringT#_WV?$StrTraitMFC_DLL#_WV?$ChTraitsCRT#_W#ATL#####ATL###Z) referenced in function "public: void __thiscall CSaSsiConsoleUi::UploadSsiCheck(void)" (?UploadSsiCheck#CSaSsiConsoleUi##$$FQAEXXZ) E:\MD_69\DeveloperConsoleUI\SaSsiConsoleUI.obj
Error 5 error LNK1120: 2 unresolved externals E:\MD_69\Debug\DeveloperConsoleUi.exe
There is no linker error for the "Add" method.
I have already included "DeveloperConsoleManager.lib" in Linker -> Input -> Additional Dependencies. Please help me find out what exactly am I doing wrong.
I would be glad to add any additional information needed.
Thanks to #Igor Tandetnik and the awesome thing that is internet, I figured it out. I am adding it as an answer so that some one else might benefit.
The problem was with CString. The project in which the function was defined was a dynamic link library (dll) and the call was being made from an MFC application. Now, the issue was that, MFC uses for CString while the non-MFC dll uses .
CString in is defined as:
typedef ATL::CStringT< TCHAR, StrTraitMFC_DLL< TCHAR > > CString;
while in is defined as:
typedef CStringT< TCHAR, StrTraitATL< TCHAR > > CString;
This, as you can clearly see is different. The workaround I used was using CAtlString instead of CString . However, please feel free to suggest any better way if you come across.

C++ DLL: unresolved external symbol

I seem to have some issues with creating new files for my project.
The issue is that in my sk_error.h file it seems to complain about unresolved external symbols (full error report below). When I place my OutOfRange class in my sk_interface.h file no one complains but when I put the class in the errors file it has issues with it.
If I was to comment out OutOfRange it works perfectly fine so I dont think that it is an issue with the DLL setup.
sk_error.h
#include <sk_platform.h>
#include <sk_interface.h>
namespace sky {
class SK_API OutOfRange : IError {
public:
OutOfRange() {
m_message = " Out Of Range";
m_value = (0 << 1);
}
std::string getMessage() override {
return m_message;
}
};
}
sk_platform.h
#if defined (SK_NONCLIENT_BUILD)
#ifndef SK_API
#define SK_API __declspec(dllexport)
#endif
#else
#ifndef SK_API
#define SK_API __declspec(dllimport)
#endif
#endif
sk_interface.h
#include <sk_platform.h>
#include <string>
namespace sky {
...
class SK_API IError {
public:
virtual std::string getMessage() = 0;
protected:
uint32_t m_value = 0;
std::string m_message = "Error not initialized";
};
}
The Client Project using the DLL
#include <sk_logmanager.h>
#include <sk_error.h>
#include <iostream>
int main() {
sky::g_LogManager.startup();
sky::OutOfRange err;
std::cout << err.getMessage() << "\n";
sky::g_LogManager.shutdown();
while (1) {}
}
Error Output
1>------ Build started: Project: SkyTest, Configuration: Debug Win32 ------
1>main.cpp
1>main.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall sky::OutOfRange::OutOfRange(void)" (__imp_??0OutOfRange#sky##QAE#XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __thiscall sky::OutOfRange::getMessage(void)" (__imp_?getMessage#OutOfRange#sky##UAE?AV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall sky::OutOfRange::~OutOfRange(void)" (__imp_??1OutOfRange#sky##QAE#XZ) referenced in function _main
1>C:\Users\Matt\Documents\Game Development\DevEnv\SkyTest\Debug\SkyTest.exe : fatal error LNK1120: 3 unresolved externals
1>Done building project "SkyTest.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
Edit:
I am using Visual Studio 2017 (could be the source of the error). The Client Project is using the .lib file.
An unresolved external is always a link error. It even has it in its name: LNK2019.
It is telling you it cannot find the implementation for sky::OutOfRange::OutOfRange()
You have it in a header somewhere and you've called it, but you have not linked to the library that implements it.
We have no way of telling you what library implements it or where it lives on your hard drive. You will have to consult the documentation for OutOfRange, the author of it, or yourself.
I can tell you that you will want to check:
right click the executable project->
properties->linker->general->additional library directories
properties->linker->input->additional dependencies
and make sure the path to the library that defines OutOfRange is in the former and the library name is in the latter.
EDIT: If the library itself has a header that imports it, as it appears from the code you posted, you just need to set up the additional directories part.
In the end, you have to consult the documentation for whatever library you are using or hit up their forums.
I am not sure but this may be related to your solution configuration and solution platform. It wasn't working for me, when I set my solution configuration to "Debug" and platform to "x64"; it started working after setting it to Release - x86

error LNK2019: unresolved external symbol error

I'm getting these error messages
2>main.obj : error LNK2019: unresolved external symbol "public: __thiscall CEngine::CEngine(void)" (??0CEngine##QAE#XZ) referenced in function _WinMain#16
2>main.obj : error LNK2019: unresolved external symbol "public: void __thiscall CEngine::SetWindowSize(int,int,char const *,int)" (?SetWindowSize#CEngine##QAEXHHPBDH#Z) referenced in function _WinMain#16
2>main.obj : error LNK2019: unresolved external symbol "public: void __thiscall CEngine::Begin(void)" (?Begin#CEngine##QAEXXZ) referenced in function _WinMain#16
2>main.obj : error LNK2019: unresolved external symbol "public: int __thiscall CEngine::GetDisplayWidth(void)" (?GetDisplayWidth#CEngine##QAEHXZ) referenced in function _WinMain#16
2>main.obj : error LNK2019: unresolved external symbol "public: int __thiscall CEngine::GetDisplayHeight(void)" (?GetDisplayHeight#CEngine##QAEHXZ) referenced in function _WinMain#16
2>C:\Users\ethan\Desktop\C++ Projects\delveenginetest\Debug\delveenginetest.exe : fatal error LNK1120: 5 unresolved externals
This is my solution:
Solution 'delveenginetest' (2 projects)
DelveEngine
Include
delve.h
Engine.h
SetupSDL.h
stdafx.h
Engine.cpp
Main.cpp
SetupSDL.cpp
This is the code for Engine.h
#pragma once
#include "SetupSDL.h"
class CEngine
{
public:
CEngine(void);
~CEngine(void);
void SetWindowSize(int winW, int winH, const char* GameName, int windowMode);
void Begin(void);
int GetDisplayWidth(void);
int GetDisplayHeight(void);
private:
int deskW;
int deskH;
bool playing;
CSetupSDL* sdl_setup;
};
Code for Engine.cpp
#include "Include/stdafx.h"
#include "Include/Engine.h"
CEngine::CEngine(void)
{
playing = true;
deskW = GetSystemMetrics(SM_CXSCREEN);
deskH = GetSystemMetrics(SM_CYSCREEN);
}
CEngine::~CEngine(void)
{
}
void CEngine::SetWindowSize(int winW, int winH, const char* GameName, int windowMode)
{
// set up SDL for use
sdl_setup = new CSetupSDL(winW, winH, GameName, windowMode);
}
void CEngine::Begin(void)
{
while (playing && sdl_setup->GetMainEvent()->type != SDL_QUIT)
{
sdl_setup->Begin();
sdl_setup->End();
}
playing = false;
}
int CEngine::GetDisplayWidth(void){ return deskW; }
int CEngine::GetDisplayHeight(void){ return deskH; }
The DelveEngine project builds successfully, whereas the delveenginetest project fails.
What's wrong? I've looked everywhere for a reason, can't find one that suits me.
Despite the fact you're not providing all the sufficient information for a correct diagnosis of your problems, I'll try to share what I could imagine that might be the reasons for the linker errors:
I suppose the project delveenginetest you mention is meant to set up unit tests for the classes from the DelveEngine project.
Since you have a Main.cpp in your DelveEngine project, I'd guess it's simply build as an executable (successfully).
Your delveenginetest needs to link to the classes provided from the DelveEngine project, but that's actually not possible, since the .exe from DelveEngine can't be used for linking, you'll need a library to import it to another executable (the unit testing framework).
I'd recommend to separate out your classes/source files from DelveEngine project to make up a static or shared library, that can be linked from an application and the test framework simultaneously from within a single VS solution:
Solution 'DelveEngine' (3 projects)
DelveEngineLib (project [.lib/.dll])
Include
delve.h
Engine.h
SetupSDL.h
Engine.cpp
SetupSDL.cpp
DelveEngine (project [.exe])
Main.cpp
delveenginetest (project [.exe])
Main.cpp (TestFramework main definition)
Since I'm not very versed with it I don't know actually, if VS 2013 supports to setup projects consuming virtual resources (think of links to sources in the actual build environment), but this could be an alternative how to setup application and unit tests without need of an extra library.

Wrapping a C++ DLL with a managed class

I'm trying to wrap a unmanaged C++ DLL with managed C++ and I keep getting linking errors.
even though I include my library.lib in the project and include the correct header file.
This is the managed class:
#pragma once
#include "..\Terminal\Terminal.h"
public ref class ManagedTerminal
{
private:
Terminal * m_unTerminal;
public:
ManagedTerminal(void)
{
m_unTerminal = new Terminal();
}
};
and this is the unmanaged class:
#include "..\Core1.h"
#include "..\Core2.h"
__declspec(dllexport) class Terminal
{
private:
CoreObj m_core;
public:
Terminal();
void Init(char* path, char* filename);
void Start();
void Stop();
void Run();
Array<Report> GetSnapshot();
~Terminal(void);
};
and the errors I get are:
Error 5 error LNK2028: unresolved token (0A0000B3) "public: __thiscall Terminal::Terminal(void)" (??0Terminal##$$FQAE#XZ) referenced in function "public: __clrcall ManagedTerminal::ManagedTerminal(void)" (??0ManagedTerminal##$$FQ$AAM#XZ) ManagedTerminal.obj TerminalWrapper
Error 6 error LNK2019: unresolved external symbol "public: __thiscall Terminal::Terminal(void)" (??0Terminal##$$FQAE#XZ) referenced in function "public: __clrcall ManagedTerminal::ManagedTerminal(void)" (??0ManagedTerminal##$$FQ$AAM#XZ) ManagedTerminal.obj TerminalWrapper
can anybody tell me what's wrong?
thanks :)
You have to match all of the build settings -- specifically the calling conventions (CDECL vs. STDCALL) -- in order to have a successful link.
Since .NET 2.0, you have also had to link to the c-runtime dynamically, so make sure that both the .dll and the managed C++ project do this.
Basically, go into the properties dialog for both projects and make sure that things that affect the call are the same.

C++ LNK2019 error with constructors and destructors in derived classes

I have two classes, one inherited from the other. When I compile, I get the following errors:
Entity.obj : error LNK2019: unresolved external symbol "public: __thiscall Utility::Parsables::Base::Base(void)" (??0Base#Parsables#Utility##QAE#XZ) referenced in function "public: __thiscall Utility::Parsables::Entity::Entity(void)" (??0Entity#Parsables#Utility##QAE#XZ)
Entity.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall Utility::Parsables::Base::~Base(void)" (??1Base#Parsables#Utility##UAE#XZ) referenced in function "public: virtual __thiscall Utility::Parsables::Entity::~Entity(void)" (??1Entity#Parsables#Utility##UAE#XZ)
D:\Programming\Projects\Caffeine\Debug\Caffeine.exe : fatal error LNK1120: 2 unresolved externals
I really can't figure out what's going on.. can anyone see what I'm doing wrong? I'm using Visual C++ Express 2008. Here are the files..
"include/Utility/Parsables/Base.hpp"
#ifndef CAFFEINE_UTILITY_PARSABLES_BASE_HPP
#define CAFFEINE_UTILITY_PARSABLES_BASE_HPP
namespace Utility
{
namespace Parsables
{
class Base
{
public:
Base( void );
virtual ~Base( void );
};
}
}
#endif //CAFFEINE_UTILITY_PARSABLES_BASE_HPP
"src/Utility/Parsables/Base.cpp"
#include "Utility/Parsables/Base.hpp"
namespace Utility
{
namespace Parsables
{
Base::Base( void )
{
}
Base::~Base( void )
{
}
}
}
"include/Utility/Parsables/Entity.hpp"
#ifndef CAFFEINE_UTILITY_PARSABLES_ENTITY_HPP
#define CAFFEINE_UTILITY_PARSABLES_ENTITY_HPP
#include "Utility/Parsables/Base.hpp"
namespace Utility
{
namespace Parsables
{
class Entity : public Base
{
public:
Entity( void );
virtual ~Entity( void );
};
}
}
#endif //CAFFEINE_UTILITY_PARSABLES_ENTITY_HPP
"src/Utility/Parsables/Entity.cpp"
#include "Utility/Parsables/Entity.hpp"
namespace Utility
{
namespace Parsables
{
Entity::Entity( void )
{
}
Entity::~Entity( void )
{
}
}
}
The relevant bit is this:
unresolved external symbol "public: __thiscall Utility::Parsables::Base::Base(void)"
You need to provide a definition for Base::Base and Base::~Base. A declaration is not good enough. Even if you have nothing to do in either function, you need to leave an empty function body, because C++ actually requires the function to exist. C++ puts things like virtual table maintenance inside your constructors and destructors, so they must be defined even if you don't need to do anything there -- C++ has to do things in there.
Are you sure Base.cpp is being included in the build?
Just encountered this exact same error today in Visual Studio 2015. Unfortunately the accepted answer didn't worked (as well as answers from many same questions). The thing that worked for me was right click on the base class cpp file, exclude and then include it again. I think somehow VS got confused while moving file around and renames and it just silently refused to compile it even though it was marked as "Included In project" = true in property editor as well as listed in vcproj file in group. This is horrible error and ended up spending good hour on it.
Either your base.cpp is not being compiled/linked or you have a misspelling in it