Why can't I see elements in a shared queue from my Perl thread?

Question

I will listen on a port (simple server) when a request is passed parse the URL and start a thread.

The thread will insert an element in a queue which is shared, and it is locked while inserting.

I am not able to get element when I call peek on queue.

use Thread qw(async); 
use Thread::Queue;

 my $DataQueue:shared = new Thread::Queue; 

 $newElement = init($user,$param,$reqest);  # init is method in ElementStructure.pm
 #after creating the element it is passes to subroutine where thread is started

sub updateData
{
    my $iElement=shift;

    $thr = async 
    { 

        {
            lock($DQueue);

            print "---->locked\n";
                    $DQueue->enqueue($iElement);
            insertdata();

        }

        print "lock released\n";

    };
}

sub insertdata
{
     my $count=0;
     while ($DataElement = $DQueue->peek($count) )
     {
    print "-- position $count\n";
    $count++;
     }
}

Answer 1

Perhaps the problem is that you use $DataQueue one place but $DQueue elsewhere? Make sure you are using strict and warnings.

If $iElement may be false (e.g. 0), you will need to say

while ( defined ( my $DataElement = $DQueue->peek($count) ) )

Correcting the variable name and putting in some code to call updateData, everything seemed to work for me.

Answer 2

Here Is the answer

use Thread qw(async); 
use Thread::Queue;

 my $DataQueue:shared = new Thread::Queue; 

 $newElement = init($user,$param,$reqest);  # init is method in ElementStructure.pm
 #after creating the element it is passes to subroutine where thread is started

 my $th=new Thread(\&updateData);
 $th->join();

sub updateData
{

        {
            lock($DQueue);

            print "---->locked\n";
                    $DQueue->enqueue($newElement);
            insertdata();

        }

        print "lock released\n";

}

sub insertdata
{
     my $count=0;
     while ($DataElement = $DQueue->peek($count) )
     {
    print "-- position $count\n";
    $count++;
     }
}