Unresolved External Symbol

[kutuup]

Hello,

I'm working on a simple winsock2 messaging program with a client and a server.

The server, which uses the same code as the client, save for some preprocessor directives, compiles fine, but the client throws up 3 unresovled external symbol errors:

Error 1 error LNK2019: unresolved external symbol "public: __thiscall Client::~Client(void)" (??1Client@@QAE@XZ) referenced in function _wmain Assignment 3 AIP 2 Client.obj

Error 2 error LNK2019: unresolved external symbol "public: int __thiscall Client::Connect(void)" (?Connect@Client@@QAEHXZ) referenced in function _wmain Assignment 3 AIP 2 Client.obj

Error 3 error LNK2019: unresolved external symbol "public: __thiscall Client::Client(void)" (??0Client@@QAE@XZ) referenced in function _wmain Assignment 3 AIP 2 Client.obj

I have linked the winsock2 library in both of the projects, but the client still throws up the errors. (Project->Properties->Configuration Properties->Linker->Input->Additional Dependencies->ws2_32.lib).

Any ideas as to why this might be?

Here is the code for the main function of the client:

#include "stdafx.h"
#include <winsock2.h>
#include <ws2tcpip.h>
#include <iostream>
#include "windows.h"
#include "Client.h"
#include "Comms.h"
#include "Server.h"
#include <exception>
#include "Server.h"


#define CLIENT
//#define SERVER

char mutexName[] = "MUTEX1";

//*******************************************************
int _tmain(int argc, _TCHAR* argv[]){

#ifdef CLIENT

	try{
		Client myClient;
		myClient.Connect();
	}

	catch( NoDllException& e){
		cout << "Error 1 : " << e.what() << endl;
	}
	catch( ClientConnectException& e){
		cout << "Error 2 : " << e.what() << endl;
	}
	catch( ClientSocketException& e){
		cout << "Error 3 : " << e.what() << endl;
	}
	catch( ClientException& e){
		cout << "Error 4 : " << e.what() << endl;
	}
#endif

#ifdef SERVER

	try{
		Server myServer;
		myServer.Listen();
	}

	catch( ServerSocketException& e){
		cout << "Error 1 : " << e.what() << endl;
	}
	catch( BindFailedtException& e){
		cout << "Error 2 : " << e.what() << endl;
	}
	catch( ListenErrorException& e){
		cout << "Error 3 : " << e.what() << endl;
	}
	catch( SocketFailedException& e){
		cout << "Error 4 : " << e.what() << endl;
	}
	catch( GameNameException& e){
		cout << "Error 5 : " << e.what() << endl;
	}
	catch( RecieveClientException& e){
		cout << "Error 6 : " << e.what() << endl;
	}
	catch( ServerSendException& e){
		cout << "Error 7 : " << e.what() << endl;
	}

#endif

	
	system("pause");
	return 0;
}
//*******************************************************

[template<>]

It appears linker is not seeing the definitions for Client. Is Client.cpp compiled and linked with application?

[kutuup]

It appears linker is not seeing the definitions for Client. Is Client.cpp compiled and linked with application?

Yes as far as I can see it is.

[template<>]

Can we see the client.h and client.cpp code?

[kutuup]

Can we see the client.h and client.cpp code?

Here you go:

Client.h:

//===================================
//==== Assignment 3 =================
//==== Damien Parsons - 20830730 ====
//==== Date - 25/03/2011 ============
//==== Client.h =====================
//===================================

#pragma once
#include "stdafx.h"
#include <winsock2.h>
#include <ws2tcpip.h>
#include "iostream"
#include "windows.h"
#include "Comms.h"

//======================================================
class ClientConnectException: public exception {
public:
  virtual const char* what() const throw() {
    return "Client: connect() - Failed to connect.";
  }
};
//======================================================
class ClientSocketException: public exception {
public:
  virtual const char* what() const throw() {
    return "Error at socket()";
  }
};
//======================================================
class ClientException: public exception {
public:
  virtual const char* what() const throw() {
    return "Client: error %ld. ";
  }
};
//======================================================
class Client:
		public Comms
{
public:
	Client(void);
	~Client(void);
	char Enter();
	int Connect();

	char receiveBuffer[200];

	SOCKET clientSocket;
	
	ClientConnectException noConnection;
	ClientSocketException noSocket;
	ClientException cException;
};
//======================================================

and client.cpp:

//===================================
//==== Assignment 3 =================
//==== Damien Parsons - 20830730 ====
//==== Date - 25/03/2011 ============
//==== Client.cpp ===================
//===================================

#include "StdAfx.h"
#include "Client.h"
//*************************************************
Client::Client(void){
	char receiveBuffer[200] = "";
}
//*************************************************
Client::~Client(void){
}
//*************************************************
int Client::Connect() throw(ClientConnectException,ClientSocketException){
	
	cout<<"\n\n"<<endl;
	cout<<"\t\t=================="<<endl;
	cout<<"\t\t------CLIENT------"<<endl;
	cout<<"\t\t=================="<<endl;
	cout<<"\n\n"<<endl;

	this->createMySocket();

	clientSocket = INVALID_SOCKET;
	clientSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (clientSocket== INVALID_SOCKET){
		throw noSocket;
		cout <<  WSAGetLastError() << endl;
		WSACleanup();
		return 0;
	}
	else{
		cout << "socket() is OK!" << endl;
	}
	sockaddr_in clientService;
	clientService.sin_family = AF_INET;
	clientService.sin_addr.s_addr = inet_addr("127.0.0.1");
	clientService.sin_port = htons(port);
	
	if (connect(clientSocket, (SOCKADDR*)&clientService, sizeof(clientService)) == SOCKET_ERROR) {
		throw noConnection;
        WSACleanup();
        return 0;
	}
	else{
       cout << "Client: connect() is OK." << endl;
       cout << "Client: Can start sending and receiving data..." << endl;
	}
	
	Enter();
	return 0;
}
//*******************************************************
char Client::Enter(){

	char buffer[200]="";

	do{	
		printf("Enter your message ");
		cin.getline(buffer,200);

		int byteCount = send(clientSocket, buffer, 200, 0);

		if(byteCount == SOCKET_ERROR){
			printf("Server send error %ld.\n", WSAGetLastError());
			return -1;
		}
		char receiveBuffer[200] = "";
		int byteCount2 = recv(clientSocket, receiveBuffer, 200, 0);
		if (byteCount2 < 0){
			throw cException;
			WSAGetLastError();
			return 0;
		}
		else { 
		    printf("Received data :  %s  \n", receiveBuffer);
		}
		char buffer[200]="";
	}while(strcmp(buffer,"QUIT")!= 0);

	WSACleanup(); 
	return 0;	
}

[template<>]

The simple sample below creates a similar error, if the definition of ~Client is missing. In your case althought the definition exists, the linker seems to not see it. When I get into this type of problem, I strip the code to its bare essentials and usually the problem becomes obvious.

class Client
{
public:
Client();
~Client();
};

Client::Client()
{
}

#ifdef MISSING
Client::~Client()
{
}
#endif
 
int main()
{
   Client c;
   return 0;
}
 
test2.obj : error LNK2019: unresolved external symbol "public: __thiscall Client::~Client(void)" (??1Client@@QAE@XZ) referenced in function _main

[kutuup]

The simple sample below creates a similar error, if the definition of ~Client is missing. In your case althought the definition exists, the linker seems to not see it. When I get into this type of problem, I strip the code to its bare essentials and usually the problem becomes obvious.

class Client
{
public:
Client();
~Client();
};

Client::Client()
{
}

#ifdef MISSING
Client::~Client()
{
}
#endif
 
int main()
{
   Client c;
   return 0;
}
 
test2.obj : error LNK2019: unresolved external symbol "public: __thiscall Client::~Client(void)" (??1Client@@QAE@XZ) referenced in function _main

I don't understand, so the definition is there in my code? So what is the problem?

[template<>]

The code looks right but the linker is not seeing the definition, therefore the error. Another possible reason may be that client.cpp is not included in the visual studio project.

[mytich]

Compiler (C/C++) advanced setting -> Calling convention should be the same for all files in your VS project. __fastcall (/Gr) is preferable for "Release" builds.

[kutuup]

Compiler (C/C++) advanced setting -> Calling convention should be the same for all files in your VS project. __fastcall (/Gr) is preferable for "Release" builds.

Sorry, what does that mean? lol I don't see any options like that in VS2008.

[mytich]

Check http://msdn.microsoft.com/en-us/library/fwkeyyhe(v=VS.90).aspx and look for /Gr /Gz or /Gd compiler options.

[kutuup]

Check http://msdn.microsoft.com/en-us/library/fwkeyyhe(v=VS.90).aspx and look for /Gr /Gz or /Gd compiler options.

Thanks, it did turn out to be a compiler issue. I couldn't find out how to fix it so I reverted to a backup and added my code back in, which solved the problem.