No, it doesn't need clarification. Synchronous signals are always always synchronous, therefore it's obvious that they cannot be handled asynchronously with <f

No, it doesn't need clarification. Synchronous signals are always always synchronous, therefore it's obvious that they cannot be handled asynchronously with <fill-in-the-blank-async-system>. It's really clear. And if you stop to think about why synchronous signals are synchronous, it's even more clear.