How would you handle such a TCP/IP process that, once you query it for data, sends it and immediately disconnects.

With threads :)

Using this multithreaded server as a stand in for your 'send 32 bytes and shutdown the connection' server: 

#! perl -slw
use strict;
use threads;
use IO::Socket::INET;

my $s = IO::Socket::INET->new( LocalPort => 9999, Listen => 255, reuse
+=>1 );
while( my $c = $s->accept ){
    threads->create( sub {
        printf "Server$$: Got %s", scalar <$c>;
        print $c chr( 65 + rand(26) ) x 32;
        $c->shutdown(2);
    } )->join;
}

[download]

And this client that starts 5 threads that each make five requests to the server, whilst the main thread retrieves the output and 'processes it': 

#! perl -slw
use strict;
use threads;
use Thread::Queue;

sub getIt {
    require IO::Socket::INET;
    my $tid = threads->self->tid;
    my( $Q ) = @_;
    my $data;
    for( 1 .. 5 ) {
        my $c = IO::Socket::INET->new( 'localhost:9999' ); ## Connect
        print $c 'Give me 32 bytes please';                ## Ask
        chomp( $data = <$c> );                             ## get
        $c->close;                                         ## close
        $Q->enqueue( "$tid:$data" );                       ## Queue
        sleep int rand( 5 );
     }
     $Q->enqueue( undef );  ## Signal thread done
}

my $Q = new Thread::Queue;
my @threads = map{ threads->create( \&getIt, $Q ) } 1 .. 5;

for( 1 .. 5 ) {                           ## Handle 5 threads dying
    while( my $in = $Q->dequeue() ) {                     ## Get data
        my( $tid, $data ) = split ':', $in; ## Separate who from what
        print "Client: Got '$data' from thread:$tid";
    }
}

$_->join for @threads; ## Wait for threads to die

[download]

A test run looks like this

[12:20:32.79] C:\test>start /b tserver

[12:20:35.60] C:\test>tclient
Server: Got Give me 32 bytes please
Client: Got 'JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ' from thread:4
Server: Got Give me 32 bytes please
Client: Got 'VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV' from thread:1
Server: Got Give me 32 bytes please
Client: Got 'EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE' from thread:3
Server: Got Give me 32 bytes please
Server: Got Give me 32 bytes please
Client: Got 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA' from thread:2
Client: Got 'YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY' from thread:5
Server: Got Give me 32 bytes please
Client: Got 'WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW' from thread:4
Server: Got Give me 32 bytes please
Client: Got 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA' from thread:4
Server: Got Give me 32 bytes please
Client: Got 'LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL' from thread:4
Server: Got Give me 32 bytes please
Client: Got 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX' from thread:5
Server: Got Give me 32 bytes please
Client: Got 'CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC' from thread:2
Server: Got Give me 32 bytes please
Client: Got 'PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP' from thread:4
Server: Got Give me 32 bytes please
Client: Got 'BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB' from thread:1
Server: Got Give me 32 bytes please
Client: Got 'JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ' from thread:3
Server: Got Give me 32 bytes please
Client: Got 'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF' from thread:1
Server: Got Give me 32 bytes please
Client: Got 'HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH' from thread:5
Server: Got Give me 32 bytes please
Client: Got 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA' from thread:2
Server: Got Give me 32 bytes please
Client: Got 'DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD' from thread:1
Server: Got Give me 32 bytes please
Client: Got 'WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW' from thread:3
Server: Got Give me 32 bytes please
Client: Got 'BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB' from thread:2
Server: Got Give me 32 bytes please
Client: Got 'WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW' from thread:5
Server: Got Give me 32 bytes please
Client: Got 'NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN' from thread:3
Server: Got Give me 32 bytes please
Client: Got 'IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII' from thread:1
Server: Got Give me 32 bytes please
Client: Got 'UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU' from thread:3
Server: Got Give me 32 bytes please
Client: Got 'TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT' from thread:2
Server: Got Give me 32 bytes please
Client: Got 'RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR' from thread:5

[download]
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re: Unexpected TCP/IP disconnect by BrowserUk
in thread Unexpected TCP/IP disconnect by carcassonne

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