Greetings Monks,

I have recently started experimenting with threads and have the following problem. Whenever I try and share a scalar ref using a queue I can't access that reference in other parts of my code by storing it in a global variable. The problem is illustrated by the code below.

P.S There is a reason I am not passing the reference directly to the function instead (even though this does seem to work) 
#!/usr/bin/env perl

use strict;
use threads;
use Thread::Queue;

my $q=Thread::Queue->new;

my $thr=async {
    my $progref;
    sub ch {
        print "In ch \$progref=$progref\n"; #progref is still undefine
+d (why?)
        $$progref=90;
    }
    $progref=$q->dequeue; #This seems to create a local $progref, but 
+it shouldn't!
    print "In main part of thread \$progref=$progref\n";
    $$progref=30; #This is applied
    ch(); #This is ignored 
};


my $prog :shared;
$q->enqueue(\$prog);
sleep 2;
print "$prog\n"; #Prints 30, not 90
$q->end;
$thr->join;

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In reply to Threads and Shared Variables by hermes1908

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