Question

Can anyone tell me why my SimpleTest application does not display “Test”?
The DLL loads successfully, I just don’t get any console output.

SimpleDLL.cpp

#include "stdafx.h"
#include "SimpleDLL.h"

#include "stdafx.h"
#include <iostream>

int Test()
{
    std::cout << "Test" << std::endl;
    return 0;
}

SimpleDLL.h

#ifndef _DLL_TUTORIAL_H_
#define _DLL_TUTORIAL_H_
#include <iostream>

#if defined DLL_EXPORT
#define DECLDIR __declspec(dllexport)
#else
#define DECLDIR __declspec(dllimport)
#endif

DECLDIR int Test();

#endif

SimpleTest.cpp

#include "stdafx.h"
#include <iostream>
#include <windows.h>

typedef int (*TestFunc)();

int main()
{
    TestFunc _TestFunc;
    HINSTANCE hInstLibrary = LoadLibrary( _T("SimpleDLL.dll"));

    if (hInstLibrary)
    {
        _TestFunc = (TestFunc)GetProcAddress(hInstLibrary, "Test");
    }
    else
    {
        std::cout << "DLL Failed To Load!" << std::endl;
    }

    if (_TestFunc)
    {
        _TestFunc();
    }

    FreeLibrary(hInstLibrary);

    return 0;
}

Answer 1

You need to declare extern "C" before __declspec(...). This is because C++ adds name decoration when you export a C++ function, and you need to declare it as a C function to have the function Test exported as just “Test”