Re: slow open() calls and o_nonblock

["Aaron Wiebe" <epiphani@gmail.com>]

On 6/4/07, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>
> > Now, I'm a userspace guy so I can be pretty dense, but shouldn't a
> > call with a nonblocking flag return EAGAIN if its going to take
> > anywhere near 415ms?
>
> Violation of causality. We don't know it will block for 415ms until 415ms
> have elapsed.

Understood - but what I'm getting at is more the fact that there
really doesn't appear to be any real implementation of nonblocking
open().  On the socket side of the fence, I would consider a regular
file open() to be equivalent to a connect() call - the difference
obviously being that we already have a handle for the socket.

The end result, however, is roughly the same.  We have a file
descriptor with the endpoint established.  In the socket world, we
assume that a nonblocking request will always return immediately and
the application is expected to come back around and see if the request
has completed.  Regular files have no equivalent.

-Aaron