I believe the problem here is the multiple calls to tie() within the same file. I, too, have been struggling to use IPC::Shareable with fork(), but I thought I'd revisit it since it came up here.

This code, refactored from a very old version of the Perl Cookbook, does what you want (I believe). Notice that there's only one call to tie(). The only places I can find that there are multiple calls is when each process is created within a different file. I'm not entirely certain yet.

Also note that I tested this with hashes, arrays and scalars along with the hash reference I've left in, and it also works with subroutines, which I left out. One last thing... the 'glue' appears to require undef when using it in this way. When I try a named glue, it fails (without the 'create' param set to true, which technically isn't needed unless an external process is using the var... again, at least from what I can tell.

use warnings;
use strict;

use IPC::Shareable;

$SIG{INT} = sub { exit; };

my $href = {count => 0};

my $ipc = tie 
            $href, 
            'IPC::Shareable', 
            undef, 
            { destroy => 1 };

for (1 .. 3) { 
    unless (fork()){
        while (1){
            $ipc->shlock();
            $href->{count}++;
            $href->{pid} = $$;
            $ipc->shunlock();
        }
        exit;
    } 
}

while (1) {
    next if ! defined $href->{pid};
    print "pid: $href->{pid}, count: $href->{count}\n";
    sleep 1;
}

[download]

Output:

pid: 19062, count: 1
pid: 19062, count: 1472
pid: 19063, count: 3070
pid: 19063, count: 4771
pid: 19062, count: 6548
pid: 19062, count: 8179
pid: 19062, count: 10070
pid: 19064, count: 11817
^C

[download]

In reply to Re: IPC:Shareable: Sharing an object between parallel processes by stevieb
in thread IPC:Shareable: Sharing an object between parallel processes by Bloehdian

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