use threads;
use threads::shared;
my $sharedTestVar :shared;

##</code><code>##

...
if(! GetOptions ('plugin=s' => \$plugin,'config=s' => \$instanceName,'debug' => \$debug, 'interface=s' => \$interface, 'mcastAddress=s' => \$mcastAddress, 'mcastPort=s' => \$mcastPort, 'file=s' => \$snoopf, 'remotePcapForwarder=s' => \$remotePCF, 'netprobe=s' => \$netprobe))
{
    usage();
    xit("incorrect options specification", 99);
}

if($debug)
{
    msg("info : turning on debug");
    $ENV{TRACE}=1;
    $DEBUG=1;
}

if(! $plugin)
{
    usage();
    xit("you must supply a plugin name", 98);
}

msg("info : plugin \"$plugin\" will be connected");
eval (require "$PALIBDIR/$plugin.pm");

##</code><code>##

$sharedTestVar=6;
$DEBUG && msg("init : set sharedTestVar == $sharedTestVar");

##</code><code>##

$mcastReaderThread=threads->new(\&doMcastSubscription, $interface,$mcastAddress,$mcastPort); 
$mcastReaderThread->detach;

##</code><code>##

sub doMcastSubscription
{
...
    while(1)
    {
	my($message,$peer);

	$drop=1 unless $peer=recv($sock,$message,1400,0);
	
	if($drop == 1)
	{
	    $DEBUG && msg("recv failed");
	    #sleep(2);
	}
	else
	{
	    $actualPlugin->processMessage("$message");
	}
        $sharedTestVar++;
        msg("in doMcastSubscription set sharedTestVar == $sharedTestVar");  	
	$drop=0;	
    }    
    
    $DEBUG && msg("leaving doMcastSubscription()");
} 

##</code><code>##

while(1)
{
...
msg("in main while loop, sharedTestVar == $sharedTestVar");
...
sleep(5);
}

##</code><code>##

sub doMcastSubscription
{
...
    while(1)
    {
	my($message,$peer);

	$drop=1 unless $peer=recv($sock,$message,1400,0);
	
	if($drop == 1)
	{
	    $DEBUG && msg("recv failed");
	    #sleep(2);
	}
	else
	{
	    $actualPlugin->processMessage("$message");
	}
	
	$drop=0;	
    }    
}

##</code><code>##

sub processMessage
{
...
     if($FeedAgent::sendRateStats)
     {
        $sharedTestVar++;
	msg("in processMessage set sharedTestVar == $sharedTestVar");             
     }     
...
}