AIO with epoll event loop

In order to use libaio with epoll event loop use eventfd(2). With eventfd you create a descriptor and add it to epoll to observe and to libaio to notify when it has some events. Excerpt from source below

if ((afd = eventfd()) == -1)
    goto err_end;
...

io_set_eventfd(&iocb, afd);
...

ev.events = EPOLLIN | EPOLLET;
ev.data.ptr = p;
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, afd, &ev) == -1) {
    log_syserr("epoll_ctl");
    goto err_end;
}

Full source is available.