As it explains quite clearly, this is &quot;portable system calls&quot;. Lightweight indeed, it&#x27;s the whole point!<p>So if you ask this question, you might as well ask why system calls are not more expansive in their capabilities.<p>I think there&#x27;s a reason, system calls are much simpler. They are building bricks. If you want to layer something complex on top, you&#x27;re free to do so.<p>About your suggestions, ACE&#x27;s documentation is particularly bad. I wouldn&#x27;t recommend it to anyone.