Questions about CMUCL...
Andrea Beber
I am a beginner.
I use CMU Common Lisp and have any questioins:
is it multithreaded (multiprocess) ?
How can I specify a timeout (I use the function accept-tcp-connection) ?
Where can I find documentations about these extensions ?
THANKS !!!
Andrea Beber: be...@irst.itc.it
Thorsten Schnier
Andrea Beber <be...@irst.itc.it> writes:
> I am a beginner.
> I use CMU Common Lisp and have any questioins:
>
> is it multithreaded (multiprocess) ?
No, it doesn't have a scheduler. You can use some event-driven functions,
but that is not the same.
>
> How can I specify a timeout (I use the function accept-tcp-connection) ?
You would have to rewrite 'accept-tcp-connection', unfortunately, and I am
not even sure if that has success (see below).
>
> Where can I find documentations about these extensions ?
>
Only in the source. Here is the definition for accept-tcp-connection
(defun accept-tcp-connection (unconnected)
(declare (fixnum unconnected))
(with-alien ((sockaddr inet-sockaddr))
(let ((connected (unix:unix-accept unconnected
(alien-sap sockaddr)
(alien-size inet-sockaddr :bytes))))
(when (minusp connected)
(error "Error accepting a connection: ~A" (unix:get-unix-error-msg)))
(values connected (slot sockaddr 'addr)))))
unix-accept is just a call to the unix function 'accept'. What this function
does depends on the way the socket was created. If it was created with a
non-blocking flag, it returns immediately, with an appropriate message (check
the unix man-page on 'accept). Now how you mark a socket nonblocking I
couldn't find out, it also depends on what hardware you are using.
(in other words, if possible at all, only with some low-level hacking)
If you are desperate, write a function in C that does the accept, possibly
setting up a timer first to interrupt itself after a certain time...
BTW: read-char-no-hang doesn't work correctly with socket-streams, it
sometimes misses new incoming data.
>
> THANKS !!!
>
>
> Andrea Beber: be...@irst.itc.it
thorsten
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\ k
\ e Thorsten Schnier
\ y
/\ \ Key Centre of Design Computing
/ / c University of Sydney
\ / e NSW 2006
\ / n
\/ t thor...@arch.usyd.edu.au
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