I am just beginning to experiment with threads. The following code works fine:

#!/usr/bin/perl -w

use strict;

my $argument=10;
my %hash = sub_returning_hash($argument);
print "a = "; print $hash{"a"}; print "\n";
print "b = "; print $hash{"b"}; print "\n";
print "c = "; print $hash{"c"}; print "\n";

sub sub_returning_hash {
my $argument=shift;
my $a=$argument+1 ; my $b=$argument+2 ; my $c=$argument+3 ; 
my %output_record = (
  "a" => "$a",
  "b" => "$b",
  "c" => "$c"
);
return %output_record;
} # sub_returning_hash
[download]

and returns:

a = 11
b = 12
c = 13
[download]

Now I want to execute the subroutine as a thread, so I try:

#!/usr/bin/perl -w

use strict;
use threads;

my $argument=10;
my $thr = threads->new(\&sub_returning_hash, $argument);
my %hash = $thr->join;
print "a = "; print $hash{"a"}; print "\n";
print "b = "; print $hash{"b"}; print "\n";
print "c = "; print $hash{"c"}; print "\n";

sub sub_returning_hash {
my $argument=shift;
my $a=$argument+1 ; my $b=$argument+2 ; my $c=$argument+3 ; 
my %output_record = (
  "a" => "$a",
  "b" => "$b",
  "c" => "$c"
);
return %output_record;
} # sub_returning_hash
[download]

but I receive:

Odd number of elements in hash assignment at test.pl line 8.
Use of uninitialized value in print at test.pl line 9.
a = 
Use of uninitialized value in print at test.pl line 10.
b = 
Use of uninitialized value in print at test.pl line 11.
c =
[download]

I tried the same returning a scalar instead of an hash, and it works fine. Any suggestion to be able to access the hash returned by the subroutine when running as a thread? Thanks!

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