I'm having a hard time storing objects in a Thread::Queue. According to the Thread::Queue documentation (BUGS section), '"bless" is not supported on shared references', so let's not go there for now and just talk about sharing ordinary references in a Thread::Queue.

As I understand it, reference sharing is _supposed_ to work fine as long as all the referants are shared in a recursive manner. (Also, threads::shared says references must be shared using &share({}) syntax. Fine..whatever.) When my references are dequeued in another thread, however, the referants appear to be empty. It appears empty regardless of how I go about sharing the entire structure. The attached code illustrates this behavior.

Also , to work around the no-shared-blessed-references problem, I can just re-bless dequeued references as long as I can assume they were all of a certain type whey they were enqueued, right?

Perl 5.8.0 (ithreads) on Red Hat 9. Help!!!! Many thanks in advance,

Preston 

#!/usr/bin/perl -wall

use strict;

#=-=-=-=-


require Exporter;
package Foo;
our @ISA = qw(Exporter);

use threads;
use threads::shared;
use Thread::Queue;

sub new {
  my $class = shift;
  my $self = {key1 => 'value1',
          key2 => 'value2'};
  share($self);
  bless($self, $class);
  return $self;
}


#=-=-=-=-


package Bar;
use threads;
use threads::shared;
use Thread::Queue;

my $q = new Thread::Queue;
my $thr = threads->new(\&monitorQueue);


# Add a reference to an empty hash.
my $hash_ref_0 = {};
print "\$hash_ref_0 is a " . ref($hash_ref_0);
&share($hash_ref_0);
$q->enqueue($hash_ref_0);


# Add a reference to a hash with something in it.
my $hash_ref_1 = {keyM => "valueM",
          keyN => "valueN"};
print "\$hash_ref_1 is a " . ref($hash_ref_1);
&share($hash_ref_1);        # Try sharing the reference.
share(%$hash_ref_1);        # Try sharing the referant.
share($hash_ref_1->{$_}) foreach(keys %$hash_ref_1); # Try sharing all
+ elements of the referant.
$q->enqueue($hash_ref_1);


# Add a blessed reference to a hash with something in it.
my $hash_ref_2 = new Foo();
print "\$hash_ref_2 is a " . ref($hash_ref_2);
&share($hash_ref_2);
$q->enqueue($hash_ref_2);


$thr->join;


sub monitorQueue {
  while (my $elem = $q->dequeue) {
    print "Removed $elem from queue";
    printHashRef($elem);
  }
}


sub printHashRef {
  my $rhash = shift;
  print "Key: '$_'\t\tValue: '$rhash->{$_}'" foreach(sort keys %$rhash
+);
}

[download]

Edited by BazB: added readmore tag.

In reply to Sharing (blessed)? references with Thread::Queue. by preston

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