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My problem is to write a server script which processes incoming queries and responds to them in the usual way ... but also runs a periodic "report" function where it talks back at the client of its own accord. The report code is therefore a seperate thread.

The problem is that I don't find a way to allow the main and reporting threads to both talk back at the client. What seems to happen is that when I hasve the "write to socket" happening in both threads, they block each other in odd ways. (The report lines seem to appear after the first char of a client line is entered.)

This may be only a win32 problem, haven't tried on linux yet.

Here's my first attempt:

use strict;
use warnings;

use threads;
use IO::Socket qw(:DEFAULT :crlf);
use Time::HiRes qw( usleep );

my $sock = new IO::Socket::INET (LocalAddr => "localhost",
                                 LocalPort => 1000,
                                 Proto => 'tcp',
                                 Listen => 1,
                                 Reuse => 1);
my $SOCK;
sub sockout{
    my $r = shift;
    print $SOCK "$r\r\n";
}

sub chatter{
    while (1){
        usleep(1000 * 1000);
        sockout "talkin to myself ...";
    }
}

$SOCK = $sock->accept();
my $thread = threads->create(\&chatter);
sockout("CONNECTED!");
while (my $line = <$SOCK>){
    sockout("You said ".$line);
}
[download]

One suggestion that has been made is to use a queue. I tried, same problem. Here it is:

use strict;
use warnings;

use threads;
use Thread::Queue;
use IO::Socket qw(:DEFAULT :crlf);
use Time::HiRes qw( usleep );

my $sock = new IO::Socket::INET (LocalAddr => "localhost",
                                 LocalPort => 1000,
                                 Proto => 'tcp',
                                 Listen => 1,
                                 Reuse => 1);
my $SOCK;
my $rq;

sub sockout{
    my $r = shift;
    print $SOCK "$r\r\n";
}

sub chatter{
    while (1){
        usleep(1000 * 1000);
        sockout "talkin to myself ...";
    }
}

sub reply_thread{
    while (1){
        while ($rq->pending){
            print "rt pr\n";
            print $SOCK $rq->dequeue;
        };
        usleep(1000 * 100);
    }
}

$SOCK = $sock->accept();

$rq = new Thread::Queue;
my $reply_thread = threads->create(\&reply_thread);
my $chatter_thread = threads->create(\&chatter);

sockout("CONNECTED!");
while (my $line = <$SOCK>){
    sockout("You said ".$line);
}
[download]

Any ideas?

In reply to sharing a socket between two threads (win32) by danmcb

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