Re: Newbie: redundant connection

[carlos calderon]

----- Original Message -----
From: "Detlef Sax" <address@hidden>
To: "carlos calderon" <address@hidden>
Cc: <address@hidden>
Sent: Sunday, June 17, 2001 3:18 PM
Subject: RE: Newbie: redundant connection



> On 17-Jun-01 carlos calderon wrote:
> [...]
>  I wrote the following piece of code:
> > /*Solution is a list*/
> > sendlist(Solution) :-
> >
> > /*create sockets*/
> > socket('AF_INET',Socket),
> > /*connect to server*/
> > socket_connect(Socket,'AF_INET'('152.xxx.xxx.xxx', 1936),
> > StreamInput,StreamOuput),
>
> Try to insert:
> add_stream_alias(Socket, socket),
> add_stream_alias(StreamInput, aliI),
> add_stream_alias(StreamInput, aliO),
>
> >/*where xxx is my server's IP address*/
> > set_stream_buffering(StreamOutput,none),
>
> set_stream_buffering(aliO,none),
>
> Comment out next 2 lines:
> > '$stream'(I) = StreamOutput,
> > write2server(Solution,'$stream'(I)),
>
> write2server(Solution,aliO),
>
> > /*close socket*/
> > socket_close(Socket).
>
> GNU Prolog (1.2.6) Documentation 6.28.2:
> socket_close(Socket)
> [...]This predicate should not be used if Socket has given rise to a
stream,
> e.g. by socket_connect/2 (section 6.28.5). In that case simply use close/2
> (section 6.10.7) on the associated stream.
>
> add_somewhere_in_your_code_to_close_after_testing_all_finished :-
> % close all streams and sockets
>         close(aliI),
>         close(aliO),
>         close(socket).
>
> Whenever possible I use aliases for streams, because my hair get more grey
> by trying operations with '$streams'. I don't care the additional space
> wasted.
>
> HTH & greetings
> Detlef
>
Thanks Detlef...

I agree with about using aliases whenever possible ..I didn't know about
add_stream_alias

However, when I do
add_stream_alias(Socket,socket)
[..]
close(Socket)
it gives me an error:
uncaught exception: error(domain_error(stream_or_alias,6),
add_stream_alias/2).
according to the manual this happens because SorA is neither a variable nor
a stream-term or alias.

I knew about socket-close(Socket). The manual recommends to use close/2 but,
it seems to me, that that only closes the stream. It doesn't destroy the
socket (so when it tries to send a new list it gives you a redundant
connection error -because of the socket_connect predicate).
I have found that both SICStus adn Quintus Prolog have a socket library
module with  socket_destroy(Socket) as a built-in predicate. Then a typical
client code would be:
client(Host,Port) :-
        socket_create(....),
        socket_connect(...),
        communicate_with_server(..) /*to implement the communication
protocol with the server*/
        socket_destroy(Socket) /*the socket is destroyed*/

I guess my question is:
how do u destroy a socket in GNU Prolog?
close(Socket) doesn't work.

Thanks..




> _______________________________________________
> Users-prolog mailing list
> address@hidden
> http://mail.gnu.org/mailman/listinfo/users-prolog
>