Disable alt-space menu on windows

winAltSpace.cpp

// disables alt-space for the whole system. To turn it off, kill its process.
// copy to C:\Users\<User>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup to run on startup
// to compile with visual studio:
// run
//   "c:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Auxiliary/Build/vcvarsall.bat" x64
// cl hookMainMini.cpp user32.lib

#include <windows.h>

LRESULT CALLBACK LowLevelKeyboardProc(int code, WPARAM wParam, LPARAM lParam) {
    if (code < 0) {
        return CallNextHookEx(0, code, wParam, lParam);
    }
    KBDLLHOOKSTRUCT *info = (KBDLLHOOKSTRUCT *) lParam;
    if (wParam == WM_SYSKEYDOWN && info->vkCode == VK_SPACE) {
        HWND foregroundWindow = GetForegroundWindow();
        if (foregroundWindow) {
            // looks like we cannot fill lparam completly, e.g. we don't get repeatCount,
            // at least set the altdown bit.
            LPARAM appLParam = KF_ALTDOWN;
            if (!PostMessageA(foregroundWindow, WM_SYSKEYDOWN, VK_SPACE, appLParam) == 0) {
                return 1;
            }
        }
    }
    return CallNextHookEx(0, code, wParam, lParam);
}

INT WinMain(HINSTANCE application, HINSTANCE hPrevInstance, PSTR lpCmdLine, INT nCmdShow) {
    WNDCLASS windowClass = {};
    windowClass.lpfnWndProc = DefWindowProc;
    windowClass.hInstance = application;
    windowClass.lpszClassName = "Hooks";

    RegisterClassA(&windowClass);

    HWND window = CreateWindowExA(0,
                                  windowClass.lpszClassName,
                                  "Hooks",
                                  0,
                                  CW_USEDEFAULT,
                                  CW_USEDEFAULT,
                                  CW_USEDEFAULT,
                                  CW_USEDEFAULT,
                                  HWND_MESSAGE, // hidden window which only dispatches messages
                                  0,
                                  application,
                                  0);

    if (!window) {
        return 1;
    }

    HHOOK llkbHook = SetWindowsHookExA(WH_KEYBOARD_LL, LowLevelKeyboardProc, 0, 0);
    if (!llkbHook) {
        return 1;
    }

    MSG msg = {};
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
  
cleanup:
    if (llkbHook) {
        UnhookWindowsHookEx(llkbHook);
    }
    return 0;
}