确保只有一个Perl程序实例正在运行的最佳方法是什么？

#!/usr/bin/perl

use Fcntl qw(:flock);
use File::Temp qw(tempfile);

my ($fh, $filename) = tempfile(UNLINK => 1);

if (!flock($fh, LOCK_EX|LOCK_NB)) {
    print "Another instance of this program is already running.\n";
    exit 1;
}

# Your program logic here

flock($fh, LOCK_UN);