#!/usr/bin/perl

    use threads;
    use threads::shared;

      my $foo : shared;

    $thr = threads->new(\&sub1, "THREAD1 :");
    $thr2 = threads->new(\&sub2, "THREAD2 :");
    @ReturnData = $thr->join; 
    print @ReturnData;
    @ReturnData = $thr2->join; 
    print @ReturnData;

    sub sub1{
        my $i;
          {
            lock $foo;
            $foo=0;
          }

        for ($i=0;$i<10000;$i++) {
      print $_[0].$i."\n";
        }
          {
            lock $foo;
            $foo=1;
          }

    print " Final value :$foo\n";
      }
    
    
    sub sub2{
        my $i;
        for ($i=0;$i<5000;$i++) {
            print $_[0].$i."\n";
        }
        $out = 1;
        while ($out) {
            {
                lock $foo;
                if ($foo == 1) {
                    $out = 0;
                }
            }
        }
        for ($i=5000;$i<10000;$i++) {
            print $_[0].$i."\n";
        }
    }

[download]

Hi Mates, can you please tell me , how the locks are been used in this programme.

i am unable to get what is happening here and how threads are working. Any Help is appreciated.

In reply to Help on Understanding Locks in Multithreading by koti688

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