dvinay has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks, Need an help here, i am using multi-threaded perl script, where i am calling an subroutine in which its accessing global variable defined in main function, now problem is that all threads are accessing this variable at same time, and i want this variable to be incremented each time this subrountine is called from main script, how can i do this below is the code for this 

use threads;
my @arr = (1,2,3,4);
my $outnumber=1;

print "\n variable outside thread that is in main program $outnumber\n
+";
my @threads;
foreach (@arr) {
   push @threads, threads->new(\&doSomething, $_, $outnumber);
}
foreach (@threads) {
   $_->join();
}

sub doSomething ()
{
  my ($thread)=@_;

  lock $outnumber;
  my $intervariable=$outnumber;
    print "\n Before increment is $intervariable\n";
    ++$intervariable;
    
    print "\n After increment is $intervariable\n";
    print "thread $thread\n";

}

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Re: Multi-threaded script
by roboticus (Chancellor) on Sep 13, 2013 at 05:05 UTC

    dvinay:

    If you'd look at the docs for threads, it would tell you the answer. You need to share your variable(s). For a description of how, see threads::shared.

    By the way, if you'd use code tags around your code, it would be easy to read your code.

    ...roboticus

    When your only tool is a hammer, all problems look like your thumb.

[reply]
      Hi, You mean to say i need to make that global variable as shared , if yes let me know how to do it. your help is much appreciated. Thanks, Vinay
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