Re: [q-lang-users] OpenBSD, threading

[<mip...@ya...>]

(OK, more agressive formatting.)

Albert Graef wrote:
> Julian Fondren wrote:
> > ;; OpenBSD [...]
> >
> > Everything compiles fine expect for
> > modules/clib/clib.c -- there I had to add an
> > "#include <unistd.h>", since something
> > apparently failed to define HAVE_UNISTD_H
>
> That's *really* strange. Could you please check the
> generated config.h (in the toplevel directory of the
> sources), to see if it defines HAVE_UNISTD_H?

It does.  With more investigation, the compilation
only falls apart when the '#include <unistd.h>' comes
*after* the '#define _XOPEN_SOURCE 500' in
modules/clib/clib.c

> Hmm, I tried to run your example, but somehow I
> can't get it to work, the accept call in the server
> always fails with EINVAL for me. Here's the call
> sequence I used for initializing the server and the
> client, I guess that's correct so far? Maybe I'm
> missing something obvious?
>
> def S = server 5001
> def C = socket AF_INET SOCK_STREAM 0
> connect C ("localhost",5001)

Huh, this seems to work with my current version.

  bwrite C (bytestr "Hello!\n")
  bstr (bread C 64)

(though I used netcat to test it, for some reason)

> Anyway, the problem with your code is that you don't
> keep the handle for the echo_loop thread. You see,
> the thread will be canceled automatically as soon as
> the thread handle T is garbage collected. Here this
> happens when server_loop FD tail-reduces to itself
> (the local T variable is not used anymore and its
> value is therefore thrown away). The solution is to
> keep track of the thread handles, either in the
> server_loop function or in echo_loop itself. The
> latter solution would be something like the
> following:

Ah, OK.  I'd actually thought of doing that, but
didn't
want to change my design until I understood why what I
had failed.  Thanks.

[snip]

> (As you'll notice I changed the second server_loop
> rule to track down the cause of the mysterious
> accept failures I encountered. Also note that you
> don't have to explicitly cancel this_thread on exit
> from echo_loop, in the second rule for echo_loop, as
> the thread will be terminated anyway when the loop
> ends.)
>
> Can you try whether this works for you?

It did =)  I ended up with a more nicely formatted
version of the following:

 server P = thread (server_loop FD)
   where FD:Int = socket AF_INET SOCK_STREAM 0,
     () = bind FD ("localhost",P),
     () = listen FD 4;
          = perror "server" otherwise;

 server_loop FD = server_loop FD
   where (C:Int,(H,P)) = accept FD,
     _ = thread (echo_loop this_thread C H P),
     _ printf "Got connection from: %s:%d\n" (H,P);
                = server_loop FD otherwise
   where _ = perror "server(accept)";

 echo_loop T FD H P = echo_loop T FD H P
   where MSG = recv FD 0 4096,
     () = echo FD MSG (bcmp MSG (bytestr ""));
                    = closesocket FD otherwise
   where
     _ = printf "Lost connection from: %s:%d\n" (H,P);

 echo FD MSG 0 = error;
 echo FD MSG _ = ()
   where _ = send FD 0 MSG;

> Cheers,
> Albert


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