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Re: 1.3.2: Cygwin && UDP && O_NONBLOCK
On Tue, Aug 14, 2001 at 01:54:27PM -0600, Troy Noble wrote:
> Roderick,
>
> Unless I misunderstood entirely, I think you've found a bug.
>
> I got the same blocking behavior you described when testing
> (after fixing many of the same things that Keith
> described in his mail). And it does appear to be inconsistent
> with behavior on Linux for the same program as you noted.
>
> Looks like there was a fix for some code related to setting up the
> non-blocking behavior in fhandler_socket.cc:fctl on Aug 13, 2001
> so the flags are set properly now, but the recvfrom appears not
> to be checking for the non-blocking flag. I updated my src tree
> from CVS today and tested, and it still exhibits the blocking
> behavior you describe.
>
> The problem appears to be the wait for an event at net.cc:93
> which looks like:
>
> switch (WSAWaitForMultipleEvents(2, ev, FALSE, WSA_INFINITE, FALSE))
>
> There seem to be at least two ways to fix it, otherwise I'd just
> submit a patch. But I don't know that I understand the philosopy
> entirely, so it'd be best to defer to Corinna's better judgement.
>
> It seems to me in net.cc:recvfrom one of the following
> needs to happen:
>
> 1. if ((h->get_flags() & O_NONBLOCK_MASK)
> || !(ovr = wsock_evt.prepare ()))
> {
> ...
>
> which would cause behavior to revert to Winsock 1.1's
> recvfrom which appears to do the right thing, at least in
> my minimal testing.
Thanks for tracking that down. I changed the code to use your
version 1 (fallback to winsock1) in case of nonblocking sockets.
Corinna
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Corinna Vinschen Please, send mails regarding Cygwin to
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