POSIX AIO uses `struct sigevent` to notify completion. On FreeBSD you can set ->sigev_notify to SIGEV_KEVENT, and ->sigev_notify_kqueue to a kqueue descriptor.

POSIX AIO uses `struct sigevent` to notify completion. On FreeBSD you can set ->sigev_notify to SIGEV_KEVENT, and ->sigev_notify_kqueue to a kqueue descriptor. As for your "performance benefit" question and nobody using it over readiness based approaches: Well yes. No idea how it compares with a traditional readiness based socket program. But it's kind of not the point either. AFAIK the scenario where POSIX AIO makes most sense is files on disk.