Hi, Nikodemus
Thanks very much, your code give me a very good "template".
I think maybe such code should live outside of USOCKET library itself, because
the connection logic various among different applications. For example, suppose
there's a hostname which can be resolved into more than 10 different addresses,
but the network application want to try at most 3 of those addresses before
signal a error. (the theory may be this: if 3 of 10 was down, all was down, no
time waste to try the other 7)
So, my job (as a USOCKET maintainer) is to make sure SOCKET-CONNECT on all
supported CL platforms could report the same USOCKET-defined error type (i.e.
USOCKET:CONNECTION-REFUSED-ERROR), so that something like following code could
be written in user code:
(defun socket-connect-2 (host port)
(let ((addresses (usocket::get-hosts-by-name host)))
(tagbody
:connect
(let ((address (pop addresses)))
(handler-bind ((usocket:connection-refused-error
#'(lambda (c)
(declare (ignore c))
(when addresses (go :connect)))))
(usocket:socket-connect address port))))))
Regards,
Chun Tian (binghe)
在 2011-3-17，16:02， Nikodemus Siivola 写道：
> Here's what I would consider one idiomatic way to try all addresses on
> using SB-BSD-SOCKETS.
>
> (defun connect-to-host (socket host port)
> (let ((addresses (host-ent-addresses (get-host-by-name host))))
> (tagbody
> :connect
> (let ((addr (pop addresses)))
> (handler-bind ((socket-error
> (lambda (e) (when addresses (go :connect)))))
> (socket-connect socket addr port))))))
>
> Cheers,
>
> -- Nikodemus
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