How can I update a global variable across threads as I am getting garbage value for the variable across threads.

Below is sample code which shows the problem

use strict;
use warnings;
use threads;

my $currentWrite = 10;
my $totalSize = 1000;
sub Progress {
    my $size = shift;
    $currentWrite += $size;
    my $currentProgress = $currentWrite / 100;
    print "Done ", $currentProgress, " of ", $totalSize, "\n";
}

sub test {
    my $countRef = shift;
    my $count = $$countRef;
    Progress ( 11);
    print "Current count is $count\n";
}

Progress(10);
my $numThreads = 5;
my @arrThreads;
for my $i ( 1 .. $numThreads) {
    my $t = threads->create( \&test, \$i);
    push( @arrThreads, $t);
}
foreach (@arrThreads) {
    my $num = $_->join;
}
[download]

Below is the output of above program.

# perl thrprog.pl
Done 0.2 of 1000
Done 0.31 of 1000
Current count is 2
Done 0.31 of 1000
Current count is 1
Done 0.31 of 1000
Current count is 3
Done 0.31 of 1000
Current count is 4
Done 0.31 of 1000
Current count is 5
[download]

How to share the data across threads so that the value get updated properly.

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