Thanks for the lead. For the sub{} share stuff, I am still not sure it's necessity. But consider the following code, If I give anything try to alter the cloned structure, it give the Thread 2 terminated abnormally: Invalid value for shared scalar error. 
$| = 1;
use Data::Dumper;

use threads;;
use threads::shared;

my @r = ( map+{ map{ $_ => [ 1 .. 2 ] } 'a' .. 'b' }, 1..2 );;
my @s : shared = map shared_clone( $_ ), @r; 

sub A {
    while ( 1 ) {
        print Dumper \@s;
        sleep 3;
    }
}

sub B {
    while ( 1 ) {
        my $cmd = <STDIN>; chomp $cmd;
        push @s, { $cmd => time }         
    }
}

$th1 = threads -> new ( 'A' ) ;
$th2 = threads -> new ( 'B' ) ;

$th1->join();
$th2->join();

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This kind of assessment ( shareable R/W stuct ) would be more prior for my needs.

And for my ultimate purpose, I wish to share a struct which carrying different on-the-fly created objects, and they can cross access each other. Of cause I can change the style to share an array to indicate a "queue" and then every objects go inside the queue to look for action. However, this leads me to think, is if there's any transparent way for a complex stuct become shareable

In reply to Re^2: How to share complex data structure in threads ? by exilepanda
in thread How to share complex data structure in threads ? by exilepanda

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