c++ windows 生成 guid

std::string getNewGuid()
{
    GUID guid;
    ::CoCreateGuid(&guid);

    const int len = 36;
    char dst[len];
    memset(dst, 0, len);
    snprintf(dst, len,
        "%08x%04x%04x%02x%02x%02x%02x%02x%02x%02x%02x",
        guid.Data1, guid.Data2, guid.Data3,
        guid.Data4[0], guid.Data4[1], guid.Data4[2],
        guid.Data4[3], guid.Data4[4], guid.Data4[5],
        guid.Data4[6], guid.Data4[7]);
    std::string out(dst);
    return std::move(out);
}