Re: A problem involving threads and http streams

Hi Anne,

Thanks for testing! I suspect that the buggy servers hangs for the
same reason on your machine as on mine, but that the error message
just isn't produced.

I don't understand this bug, and I don't understand how the error
message relates to the behaviour. There may be something about threads
and the http libs in SWI Prolog that I still haven't understood (which
sure is possible), but at this point I tend to think that the
erroneous behaviour is caused by a bug in one of the libraries.

Best regards,
Torbjörn


On Sat, Sep 14, 2013 at 9:38 PM, Anne Ogborn <[email protected]> wrote:
> The mystery deepens.
>
> On 6.4.1 on 64 bit windows 7 on my machine the test client and working version work
>
> while the buggy version hangs with no error message.
>
>
>
>
> ----- Original Message -----
> From: Torbjörn Lager <[email protected]>
> To: "[email protected]" <[email protected]>
> Cc:
> Sent: Saturday, September 14, 2013 3:39 AM
> Subject: [SWIPL] A problem involving threads and http streams
>
> Dear all,
>
> In connection with my work on Pengine I have run into an issue I don't
> understand.
>
> The help you see the problem I have attached a zip archive with three
> small files, two servers and one client:
>
> test_server_buggy.pl
> test_server_working.pl
> test_client.pl
>
> The difference between test_server_working.pl and test_server_buggy.pl
> is very small. In test_server_working.pl I use a message queue with a
> hard coded name 'out'. This works but isn't good enough since my
> application requires that the name of the message queue is unique. In
> test_server_buggy.pl I use http_session_assert/1 and
> http_session_data/1 to remember the unique message queue name as given
> by message_queue_create/1. This doesn't work, since an error
>
> error(existence_error(stream,<stream>(0x7fb2d9201fb0)),context(http_stream:is_cgi_stream/1,_G132))
>
> is thrown. I don't understand why this happens and how to work around it.
>
> I use the latest SWI Prolog developer version on a Mac.
>
> Best regards,
> Torbjörn
>
> --
> Torbjörn Lager
> Professor of General and Computational Linguistics
> Department of Philosophy, Linguistics and Theory of Science
> University of Gothenburg
> Box 200, SE-405 30 Gothenburg, Sweden
> Phone: +46317864962
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-- 
Torbjörn Lager
Professor of General and Computational Linguistics
Department of Philosophy, Linguistics and Theory of Science
University of Gothenburg
Box 200, SE-405 30 Gothenburg, Sweden
Phone: +46317864962