Die you dirty DLL!

Ok so I'm trying to load a function from a DLL using GetProcAddress. I've got this DLL:

Code:

extern "C" __declspec(dllexport) HWND WINAPI WWNewWindow(WNDPROC lpfnWndProc, LPSTR lpszClassName,
                                                  LPSTR lpszWindowName, int x, int y,
                                                  int width, int height, DWORD dwStyle)
{
    WNDCLASSEX wc;
    HWND hWnd;

    wc.cbClsExtra = 0;
    wc.cbSize = sizeof(wc);
    wc.cbWndExtra = 0;
    wc.hbrBackground = static_cast<HBRUSH> (GetStockObject(GRAY_BRUSH));
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
    wc.hInstance = NULL;
    wc.lpfnWndProc = lpfnWndProc;
    wc.lpszClassName = lpszClassName;
    wc.lpszMenuName = NULL;
    wc.style = CS_VREDRAW | CS_HREDRAW;

    if (! RegisterClassEx(&wc)) return NULL;
    hWnd = CreateWindow(NULL, lpszWindowName, dwStyle, x, y, width, height, NULL, NULL, NULL, NULL);

    return hWnd;
}

With this trying to load it:

Code:

typedef HWND (WINAPI *lpfnWWNewWindow)(WNDPROC lpfnWndProc, LPSTR lpszClassName, LPSTR lpszWindowName,
                                       int x, int y, int width, int height, DWORD dwStyle);

lpfnWWNewWindow WWNewWindow;

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

HRESULT LoadWindowWrapper()
{
    HMODULE hmWindowWrapperDLL;

    hmWindowWrapperDLL = LoadLibrary("WindowWrapper.dll");
    if (! hmWindowWrapperDLL) return E_FAIL;

    WWNewWindow = (lpfnWWNewWindow) GetProcAddress(hmWindowWrapperDLL, "WWNewWindow");
    if (! WWNewWindow) return E_FAIL;
    return S_OK;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    HWND hWnd;

    if (SUCCEEDED(LoadWindowWrapper()))
    {
        hWnd = WWNewWindow(WndProc, "D3DApp", "Hello Ace!", 0, 0, 300, 300, WS_OVERLAPPEDWINDOW);
        if (! hWnd)
        {
            MessageBox(0, "Error creating window", "Error", MB_OK | MB_ICONERROR);
            return 1;
        }
    }
    else
    {
        MessageBox(0, "Error loading DLL", "Error", MB_OK | MB_ICONERROR);
        return 1;
    }

    return 0;
}

But it doesn't retrieve the function address. I've stepped though it and get an Access Violation *something* at address 0x00000000 when it gets to the call in WinMain (if I remove the error checking in LoadWindowWrapper, obviously).

I can't see what's wrong with this. I hate this platform sometimes.

You need to use a .def file to export the functions from your DLL. A sample .def file will look like this and needs to be added to the project:

Code:

LIBRARY    "MyDllName"
EXPORTS
    WWNewWindow

See 'Why can't I GetProcAddress a function I dllexport'ed?'.

Ah I thought that's what __declspec(dllexport) did. Thanks.