// Minimal Win32 window — the irreducible message-pump sequence GLFW/SDL/winit wrap
// on Windows: RegisterClassExW -> CreateWindowExW -> ShowWindow -> GetMessage /
// DispatchMessage, with a WndProc handling WM_PAINT/WM_DESTROY. Uses druntime's
// built-in `core.sys.windows` bindings (the windows.h projection that ships with
// LDC/DMD) — no third-party. For full SDK coverage the windows-d package is the
// upgrade; see ../index.md (the Win32 OS-API survey).
//
// Bounded: paints once then PostQuitMessage so CI never blocks. Windows always has
// a window station (even on a headless CI runner), so no SKIP gate is needed.
module 
(module) appapp;

import 
(package) corecore.
(package) core.syssys.
(package) core.sys.windowswindows.
(module) core.sys.windows.windows
Windows API header module
Translated from MinGW API for MS-Windows 4.0
Source
core/sys/windows/windows.d
@licenseBoost License 1.0windows;
import 
(package) corecore.
(package) core.stdcstdc.
(module) core.stdc.stdio
D header file for C99 <stdio.h>
pubs.opengroup.org/onlinepubs/009695399/basedefs/stdio.h.html, stdio.h
Source
core/stdc/stdio.d
@copyrightCopyright Sean Kelly 2005 - 2009.@licenseDistributed under the
Boost Software License 1.0.
(See accompanying file LICENSE)@authorsSean Kelly,
Alex Rønne Petersen@standardsISO/IEC 9899:1999 (E)stdio : 
(alias) app.printf = int core.stdc.stdio.printf(scope const(char*) format, scope const ...) nothrow @nogcprintf;

extern (Windows) LRESULT 
app.wndProcwndProc(HWND 
(parameter) HWND hwndhwnd, UINT 
(parameter) UINT msgmsg, WPARAM wParam, LPARAM lParam) nothrow
undefined identifier `LRESULT`
undefined identifier `HWND`
undefined identifier `UINT`
undefined identifier `WPARAM`
undefined identifier `LPARAM`
{
    switch (msg)
    {
    case WM_PAINT:
        PAINTSTRUCT 
_error_ psps;
        HDC 
_error_ hdchdc = BeginPaint(hwnd, &ps);
        RECT 
_error_ rcrc;
        GetClientRect(hwnd, &rc);
        FillRect(hdc, &rc, cast(HBRUSH)(COLOR_WINDOW + 1));
        EndPaint(hwnd, &ps);
        PostQuitMessage(0); // bounded: exit after the first paint
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    default:
        return DefWindowProcW(hwnd, msg, wParam, lParam);
    }
}

int 
int D main()main()
{
    HINSTANCE 
(local variable) _error_ hInsthInst = GetModuleHandleW(null);
undefined identifier `HINSTANCE`
undefined identifier `GetModuleHandleW`
    auto 
(local variable) wstring clsNameclsName = "SparklesWin32"w;

    // 1. Register the window class (WndProc + class name).
    WNDCLASSEXW 
(local variable) _error_ wcwc;
undefined identifier `WNDCLASSEXW`
    wc.cbSize = WNDCLASSEXW.sizeof;
    wc.lpfnWndProc = &wndProc;
    wc.hInstance = hInst;
    wc.lpszClassName = clsName.ptr;
    wc.hCursor = LoadCursorW(null, IDC_ARROW);
    if (!RegisterClassExW(&wc))
undefined identifier `RegisterClassExW`
    {
        
int core.stdc.stdio.printf(scope const(char*) format, scope const ...) nothrow @nogcprintf("RegisterClassExW failed (%lu)\n", GetLastError());
undefined identifier `GetLastError`
        return 1;
    }

    // 2. Create a standard overlapped (titled, resizable) top-level window.
    HWND 
(local variable) _error_ hwndhwnd = CreateWindowExW(0, clsName.ptr, "Sparkles · Win32"w.ptr,
undefined identifier `HWND`
undefined identifier `CreateWindowExW`
        WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 480, 320,
        null, null, hInst, null);
    if (hwnd is null)
    {
        
int core.stdc.stdio.printf(scope const(char*) format, scope const ...) nothrow @nogcprintf("CreateWindowExW failed (%lu)\n", GetLastError());
undefined identifier `GetLastError`
        return 1;
    }

    // 3. Show it and run the message pump until WM_QUIT.
    ShowWindow(hwnd, SW_SHOW);
undefined identifier `ShowWindow`
    UpdateWindow(hwnd);
undefined identifier `UpdateWindow`

    MSG 
(local variable) _error_ msgmsg;
undefined identifier `MSG`
    while (GetMessageW(&msg, null, 0, 0) > 0)
undefined identifier `GetMessageW`
    {
        TranslateMessage(&msg);
undefined identifier `TranslateMessage`
        DispatchMessageW(&msg);
undefined identifier `DispatchMessageW`
    }
    
int core.stdc.stdio.printf(scope const(char*) format, scope const ...) nothrow @nogcprintf("ok: created a Win32 window and pumped messages to WM_QUIT\n");
    return cast(int) msg.wParam;
}