Hi Monks

I try to handle the multithread program.
I find that perl have a core module call threads, and it is seen to be solving the problem.
Then try to use threads, then the question arises.
I tried this use threads::shared's funciotn,
lock().
Complete code looks like:

#!/usr/bin/perl 
use utf8;
use feature qw( say );
use threads;
use threads::shared;
use Data::Dumper;
use Storable qw ( freeze thaw );

my $LockVar :shared;
$LockVar = "default";
my $LockArray :shared;

$Lock3Sec = threads->new(
    {'void' => 'void'},
    sub {
        {
            say "the lock var default value is {$LockVar}";
            lock($LockVar) or warn "cannot lock the var because {$!}\n
+";
            sleep 3;
            say $LockVar;
        }
    },
);

$Lock3Sec->detach();

$TryToReadLockVar = threads->new(
    {'void' => 'void'},
    sub {
        my $count = 1;
        while( $LockVar eq 'default'){
            say "try to modify the Lock var {$count} time";
            $count += 1;
            $LockVar = 'this lock var has been change' or redo;
        }
    },
);

$TryToReadLockVar->join();
[download]

the out put is :

the lock var default value is {default}
try to modify the Lock var {1} time
[download]

Feel it hasn't locked, and where it went wrong?

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