From: Eric Wong <normalperson@...>
Date: 2011-04-14T04:32:06+09:00
Subject: [ruby-core:35746] Re: [Ruby 1.9 - Bug #4558]	TestSocket#test_closed_read fails after r31230

KOSAKI Motohiro <kosaki.motohiro@gmail.com> wrote:
> > Issue #4558 has been updated by Eric Wong.
> >
> > I consider either Errno::EBADF or IOError to be acceptable.
> 
> Hmm...
> I can't agree this. If EBADF can be observed, we can observe completely
> unrelated file when a fd number was recycled just after close.

Actually, I expect EBADF make any read/write-retry loop stop
immediately, but yes, exposing IOError to user is better.

> Hmm...
> If windows can't implement close() case, I doubt r30852 is correct fix.
> Is this really worth that *nix and windows have different spec?

If r30852 is reverted, Linux (and maybe other *nix) will still break
threads out of blocking read/write with EBADF and
rb_io_wait_*able(fptr->fd) will raise IOError as long as we
assign fptr->fd = -1 before the actual close() call in IO#close.

Maybe Windows (and possibly other OS) will be forced to call do_select()
to implement behavior consistent with Linux.

On a related note, r30852 also has the problem with making IO#close an
O(n) operation since it needs to scan through all threads (and I'd like
to run thousands of threads :>).

-- 
Eric Wong