package printname;

use strict;
use warnings;

my $name = ();

printname($name);

sub printname { 
     ($name) = @_;
    print "Hello, $name\n";
}


1;

##</code><code>##

#!/usr/bin/perl

use strict;
use warnings;
use lib "C:/Perl64/lib/printname";
use printname;

printname("John");

##</code><code>##

C:\Scripts>perl  testmodule.pl
Use of uninitialized value $name in concatenation (.) or string at C:/Perl64/lib/printname/printname.pm line 12.

Hello,
Undefined subroutine &main::printname called at testmodule.pl line 8.