ISAI student has asked for the wisdom of the Perl Monks concerning the following question:

Hello all. I am in the process of migrating a very messy code, partially working. In my work (I have done virtually no threaded work before) I came across a code that assigns a reference to a shared hash to a value in another shared hash. I added cluck to get the address info, and The value assigned is different than the value stored, if I read the output correctly Code is: 
my %all_shary_for_subs           :shared;
my %sim_info                     :shared;     $all_shary_for_subs{'%si
+m_info'}=\%sim_info;
cluck("the sim_info glob ref is:" . \%sim_info . "\n" );
cluck("And in the hash it is:" . $all_shary_for_subs{'%sim_info'} . "\
+n"  ) ;

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The output of the code is the following (everything else is just use Carp, threads, threads::shared and comments)

the sim_info glob ref is:HASH(0x241bea8) at /edata/eng/ldagan/voodoo_from_1.1.7.b4/DesignLibs/ScriptLib/Generic/WMPerl/voodoo/voodoo_beta.pl line 81 And in the hash it is:HASH(0x2e42990) at /edata/eng/ldagan/voodoo_from_1.1.7.b4/DesignLibs/ScriptLib/Generic/WMPerl/voodoo/voodoo_beta.pl line 82

Why are the two addresses different?

Replies are listed 'Best First'.
Re: refering to 1 shared hash from another
by Random_Walk (Prior) on Apr 24, 2013 at 11:16 UTC

    This works for me

    use threads::shared;
use Carp qw(cluck);

my %all_shary_for_subs           :shared;
my %sim_info                     :shared;     

$all_shary_for_subs{'%sim_info'}=\%sim_info;

cluck("the sim_info glob ref is:" . \%sim_info . "\n" );
cluck("And in the hash it is:" . $all_shary_for_subs{'%sim_info'} . "\
+n"  )

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    Output:

    the sim_info glob ref is:HASH(0x94b194)
 at C:\Documents and Settings\1161732\Perltest\scratch.pl line 9.
And in the hash it is:HASH(0x94b194)
 at C:\Documents and Settings\1161732\Perltest\scratch.pl line 10.

    [download]

    Where is the rest of your code? This bit is missing the use so I gues it is a fragment pulled from something larger. Can you please post running code that shoes the behaviour you are seeing?

    Cheers,
    R.

    Pereant, qui ante nos nostra dixerunt!
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      Same with me (on Cygwin though). This is a bit of a "Me too!" response, but thought knowing that the problem is not repeatable would be helpful.

      If any of my proposed solutions have minor errors, it's because I don't waste my genius on trivial matters. :-P
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        Well, here is the code: 
        use strict ;
use warnings;
use Thread;
use threads::shared;
use Carp qw (cluck) ;
my %all_shary_for_subs           :shared;
my %sim_info                     :shared;     

$all_shary_for_subs{'%sim_info'}=\%sim_info;

cluck("the sim_info glob ref is:" . \%sim_info . "\n" );
cluck("And in the hash it is:" . $all_shary_for_subs{'%sim_info'} . "\
+n"  );

        [download]
        Version is: This is perl, v5.10.0 built for x86_64-linux-thread-multi However, removing the  use Thread gives the correct results...
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