Question

Possible Duplicate:
What is an undefined reference/unresolved external symbol error and how do I fix it?

I’m learning C++ and I have a compiling problem in my project.
I have read tons of post with this error on the title but I cant find where the problem is.

I have a method call in my Main function that is responsible for the error. Whenever I comment the line the project compiles perfect.

The code is the following:

Main.cpp

#pragma once 
#include "stdafx.h"
#include <iostream>
#include <sstream>
#include <WinSock.h>
#include <Windows.h>
#include <string.h>
#include "NetUtils.h"
#include "Utils.h"
#include "FileUtils.h"
#include "SendMail.h"
using namespace std;



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

    SendMail *mail = new SendMail("[e-mail]","Envio de C++","Cuerpo del mail");    
    char* msg="";   
    mail->SendNow();
    ...

This method mail->SendNow is the one I comment to solve the problem, so I guess
I have some kind of header declaration problem inside of SendMail.cpp or SendMail.h

Now the rest of the classes and headers:

SendMail.h

#pragma once
#ifndef SENDMAIL_H
#define SENDMAIL_H


class SendMail

{
public:
    SendMail(char* c_to, char* c_subject, char* c_body);
    void Check(int iStatus, char *szFunction);
    void SendNow();
    char * to;
    char * subject;
    char * body;    
};


#endif

SendMail.cpp

#define WIN32_LEAN_AND_MEAN

#pragma once
#include "SendMail.h"
#include <stdio.h>
#include <stdlib.h>
#include <fstream>
#include <iostream>
#include <windows.h>
#include <winsock2.h>



#pragma comment(lib, "ws2_32.lib")
using namespace std;

// Insist on at least Winsock v1.1
const int VERSION_MAJOR = 1;
const int VERSION_MINOR = 1;

#define CRLF "\r\n"                 // carriage-return/line feed pair



SendMail::SendMail(char* c_to, char* c_subject, char* c_body)
{
    to = c_to;
    subject= c_subject;
    body = c_body;

}

// Basic error checking for send() and recv() functions
void Check(int iStatus, char *szFunction)
{
  if((iStatus != SOCKET_ERROR) && (iStatus))
    return;

  cerr << "Error during call to " << szFunction << ": " << iStatus << " - " << GetLastError() << endl;
}

void SendNow()
{
    // WSADATA     WSData;  

    ///* Attempt to intialize WinSock (1.1 or later)*/
    //  if(WSAStartup(MAKEWORD(VERSION_MAJOR, VERSION_MINOR), &WSData))
    //  {
    //  cout << "Cannot find Winsock v" << VERSION_MAJOR << "." << VERSION_MINOR << " or later!" << endl;
    //  ErrMsg="Cannot find Winsock v";
    //  return;     
    //  }
}

AS you can see the method Send is commented out so I cant figure out what the problem is.

The compiler output is:

Error   6   error LNK1120: 1 unresolved externals   C:\Users\clanderasm\Documents\Visual Studio 2010\Projects\LandeTestConsole\Debug\LandeCplusConsole.exe  LandeCplusConsole
Error   5   error LNK2019: unresolved external symbol "public: void __thiscall SendMail::SendNow(void)" (?SendNow@SendMail@@QAEXXZ) referenced in function _main    C:\Users\clanderasm\Documents\Visual Studio 2010\Projects\LandeTestConsole\LandeCplusConsole\LandeCplusConsole.obj  LandeCplusConsole

Answer 1

Did you mean

void SendMail::Check(int iStatus, char *szFunction)
void SendMail::SendNow()

instead of

void Check(int iStatus, char *szFunction)
void SendNow()