> (in which case you'll get an EAGAIN error instead of it blocking). You won't. O_NONBLOCK cannot be used with regular files. That part of the manpage is discu

> (in which case you'll get an EAGAIN error instead of it blocking). You won't. O_NONBLOCK cannot be used with regular files. That part of the manpage is discussing other non-socket file types. Disk i/o via write(2) is always a blocking call. Always. 100% of the time, no exceptions.