Rieccomi: come si crea un bottone? Cosa c'è di sbagliato in questo:
codice:
#include <stdio.h>
#include <windows.h>

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
int RegisterDefaultClass(HINSTANCE hInstance);

HWND window;
HWND button;

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    MSG Msg;

    if (!(RegisterDefaultClass(hInstance)))
    {
        return 1;
    }

    window = CreateWindow (
                                "defaultClass",
                                "Window!!",
                                WS_OVERLAPPEDWINDOW,
                                CW_USEDEFAULT,
                                CW_USEDEFAULT,
                                250,
                                250,
                                (HWND) NULL,
                                (HMENU) NULL,
                                hInstance,
                                NULL
                             );

    if (!window)
    {
        return 1;
    }

    button = CreateWindow (
                            "Button",
                            "Button!!",
                            0,
                            2,
                            2,
                            50,
                            50,
                            window,
                            (HMENU) NULL,
                            hInstance,
                            NULL
                        );

    if (!button)
    {
        return 2;
    }

    ShowWindow(window, SW_SHOW);
    UpdateWindow(window);

    while(GetMessage(&Msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return Msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch(msg)
    {
        case WM_CLOSE:
            DestroyWindow(hwnd);
        break;
        case WM_DESTROY:
            PostQuitMessage(0);
        break;
        default:
            return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

int RegisterDefaultClass(HINSTANCE hInstance)
{
    const char g_szClassName[] = "defaultClass";
    WNDCLASSEX wc;

    wc.cbSize        = sizeof(WNDCLASSEX);
    wc.style         = 0;
    wc.lpfnWndProc   = WndProc;
    wc.cbClsExtra    = 0;
    wc.cbWndExtra    = 0;
    wc.hInstance     = hInstance;
    wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH) (COLOR_WINDOW);
    wc.lpszMenuName  = NULL;
    wc.lpszClassName = g_szClassName;
    wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);

    if(!(RegisterClassEx(&wc)))
    {
        return 0;
    }
}
?

Si vede solo la finestra ma non il bottone o.O