self_elevation.cpp

class ScopeGuard
{
public:
    ScopeGuard( std::function< void() > onScopeExit ) { m_onScopeExit = onScopeExit; }
    ~ScopeGuard() { m_onScopeExit(); }
private:
    std::function< void() > m_onScopeExit;
};

#define SCOPEGUARD_LINENAME_CAT(name, line) name##line
#define SCOPEGUARD_LINENAME(name, line) SCOPEGUARD_LINENAME_CAT(name, line)

#define OnScopeExit( callback ) ScopeGuard SCOPEGUARD_LINENAME( myScopeGuard, __LINE__ ) ( [&] { callback; } );

BOOL IsProcessElevated()
{
    BOOL isElevated = FALSE;
    HANDLE hToken = NULL;
    DWORD errCode = 0;

    BOOL ret = OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &hToken);
    errCode = GetLastError();
    OnScopeExit(
    
        if (hToken)
        {
            CloseHandle(hToken);
            hToken = NULL;
        }
    );

    if (!ret)
    {
        throw errCode;
    }

    TOKEN_ELEVATION elevationInfo;
    DWORD retSize = 0;
    if (!GetTokenInformation(hToken, TokenElevation, &elevationInfo,
                             sizeof(elevationInfo), &retSize))
    {
        errCode = GetLastError();
        throw errCode;
    }

    isElevated = elevationInfo.TokenIsElevated;

    return isElevated;
}



void OnCommand(HWND hWnd, int id, HWND hwndCtl, UINT codeNotify)
{
    switch (id)
    {
        case IDC_BTNELEVATION:
            BOOL isElevated = IsProcessElevated();
            if (isElevated)
            {
                MessageBox(hWnd, L"Arealdy run at full administrator token",
                           L"warning", MB_OK | MB_ICONEXCLAMATION);
                return;
            } 
            else
            {
                wchar_t path[MAX_PATH];
                if (GetModuleFileName(NULL, path, MAX_PATH))
                {
                    SHELLEXECUTEINFO sei = {sizeof(SHELLEXECUTEINFO)};
                    sei.lpVerb = L"runas";
                    sei.lpFile = path;
                    sei.hwnd = hWnd;
                    sei.nShow = SW_NORMAL;

                    if (!ShellExecuteEx(&sei))
                    {
                        DWORD errCode = GetLastError();
                        if (errCode == ERROR_CANCELLED)
                        {
                            // cancelled elevation
                        }
                    }
                    else
                    {
                        
                    }
                }
            }

            break;
    }
}