use strict;
use warnings;

use Fcntl ':flock';

open my $fh1, '>>', 'moo'
or die "Cannot open moo for appending (1): $!\n";

print(flock($fh1, LOCK_EX | LOCK_NB) ? 1 :0, "\n");

open my $fh2, '>>', 'moo'
or die "Cannot open moo for appending (2): $!\n";

print(flock($fh2, LOCK_EX | LOCK_NB) ? 1 :0, "\n");