winsamp.d and -O

[Andrej Mitrovic]

To make the example compile with optimizations, you have to trick the
compiler so it can't determine whether it's a null dereference at
compile-time. Change the code to this:

int* p;
extern (Windows)
int WindowProc(HWND hWnd, uint uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
        case WM_COMMAND:
        {
            switch (LOWORD(wParam))
            {
                case IDC_BTNCLICK:

                    if (HIWORD(wParam) == BN_CLICKED)
                        MessageBoxA(hWnd, "Hello, world!", "Greeting",
                                    MB_OK | MB_ICONINFORMATION);

                    break;

                case IDC_BTNDONTCLICK:

                    if (HIWORD(wParam) == BN_CLICKED)
                    {
                        MessageBoxA(hWnd, "You've been warned...",
"Prepare to GP fault",
                                    MB_OK | MB_ICONEXCLAMATION);
                        *p = 1;
                    }

... more code ...

And then it will compile and throw at runtime when u press the dontclick button.