use strict;
use threads;
use threads::shared;
my $i :shared;
$i = 1;

# Time and code passes.
for my $id (@article_id) {
    lock($i);
    print "$i\n";
    $i++;
}
# More code.

##</code><code>##

use strict;
use threads;
use threads::shared;

{
    my $i :shared;
    sub get_i {
        lock($i);
        return ++$i;
    }
}

# Time and code passes.
for my $id (@article_id) {
    my $i = get_i();
    print "$i\n";
    # Do lengthy processing.
}
# More code.