std::wstring GetUniqueTempDirectoryPrefix()
{
    wchar_t tmpdir[MAX_PATH + 1];
    if (GetTempPath(MAX_PATH + 1, tmpdir) == 0)
        throw Win32Exception("Cannot create temporary directory");

    std::wstring dir(tmpdir);
    dir += L"Update-";
    return dir;
}
std::wstring GetUniqueTempDirectoryPrefix()
{
    wchar_t tmpdir[MAX_PATH + 1];
    if (GetTempPath(MAX_PATH + 1, tmpdir) == 0)
        throw Win32Exception("Cannot create temporary directory");

    std::wstring dir(tmpdir);
    dir += L"Update-";
    return dir;
}