Hello, I'm just a Windows programmer and now learning *nix APIs. I want to know how people use aio and socket kqueue together.
Recently I'm learning I/O APIs and noticed that aio_* functions seeem to be the only way to perform asynchronism I/O on disk files. The interface is just like overlapped I/O on Windows. But the only usable way I found, to wait for the operation's completion or to notice me that it finished, which is usable on NetBSD, is the API aio_suspend. I searched the Internet and found 4 ways to implement this: realtime signal, kqueue, callback function and aio_suspend/aio_waitcomplete. Unluckily, according to this ( http://ftp.netbsd.org/pub/NetBSD/NetBSD-current/src/doc/TODO.kqueue ) document I know that currently NetBSD's kqueue doesn't support aio events. Sigevent manual ( http://netbsd.gw.com/cgi-bin/man-cgi?sigevent ) shows that neither realtime signal nor SIGEV_THREAD flag (by which callback notification implement) is supported on NetBSD. The existing practise to handle sockets in a network server prefers I/O completion port on Windows, kqueue on *BSD and epoll on Linux. I/O completion port handles file read/write operation as well, while kqueue on FreeBSD seems (I have not yet tried) to work with aio operations. Through fdevent/fdsignal API Linux handles signals via epoll. By this way there won't be situation that a process or thread is "waiting for a single operation" (synchronism I/O). So how could I use kqueue (to handle sockets) and aio (to handle regular files on disk) on NetBSD to achieve the same goal? By the way, since the realtime signal feature is not usable on NetBSD and timer_create sends notice by realtime signal, does it mean that timer_create will not work on NetBSD? So generally how a time-out feature is implement in a network server on NetBSD? Sorry for poor English. Thanks in advance. Regards, LeiMing
