To make this discussion complete, on the other hand, most of the time, it is a better idea to return array ref, instead of array, regardless whether the program is multi-threaded: (In this way, you don't need to worry about the context any more)

use strict;
use warnings;
use Data::Dumper;
use threads;

my $thr = threads->new(\&sub1);

my $ReturnData = $thr->join;
print Dumper($ReturnData);

$ReturnData = sub1();
print Dumper($ReturnData);

sub sub1
{
    return ["Fifty-six", "foo", 23];
}
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This prints:

$VAR1 = [
          'Fifty-six',
          'foo',
          23
        ];
$VAR1 = [
          'Fifty-six',
          'foo',
          23
        ];
[download]