use strict;

##</code><code>##

    print " ", Hello, ", ", World::ALL, "!\n";
    # prints " Hello, World::ALL!"

##</code><code>##

    print " ", Hello(), ", ", $World::ALL, "!\n";

##</code><code>##

    use Fcntl qw( LOCK_EX LOCK_NB );
    flock FILE, LOCK_EX|LOCK_NB or die "File already locked"
    
##</code><code>##

    sub Log {
        warn localtime(), ": ", @_, "\n";
    }
    Log "Ready.";
    
##</code><code>##

    sub Log;
    Log "Ready.";
    sub Log {
        warn localtime(), ": ", @_, "\n";
    }
    
##</code><code>##

    $o= My::Package->new();
    
##</code><code>##

    $o= My::Package()->new();
    
##</code><code>##

    $o= My::Package::->new();
    
##</code><code>##

    use vars qw( $this $that );
    my $varname= @ARGV ? "this" : "that";
    ${$varname}= "In use"; # This line uses a symbolic reference.