#! /usr/bin/perl

use strict;
use warnings;
use vars qw(@ISA @EXPORT $VERSION);

# include MODUL in module search path
BEGIN { push(@INC,"Z:/test"); }

use test::log;



my @XLOGVALUES001;
my $XLOGVALUES001;

while(@XLOGVALUES001)
{
shift(@XLOGVALUES001);
}

$XLOGVALUES001[0] = "1";        #logfile schreiben: ja = 1     nein = 2
$XLOGVALUES001[1] = "logfile";  #name des logfiles:  "logfile.txt"
$XLOGVALUES001[2] = 'C:\WINNT\system32\config'; #pfad des logfiles:   


&test::log::logfilename(\@XLOGVALUES001);


$log2 = test::log->logfilename();
print "Zurueckgegebener Wert von der subroutine: ".$log2;

package test::log;

use strict;
use warnings;
$test::log::VERSION = "0.0.1";

#============================================================================
## @cmethod
# The default constructor of class test::log
#============================================================================
sub new {
        my $this=shift;
        my $class=ref($this) || $this;
        my $self= {};

        #class attributes
        $self->{attr1}=undef;

        #bless the object
        bless($self,$class);

        #return the reference to the blesses object
        return($self);
}


sub logfilename {
        my $self = shift;
                        
        my $logfilename;
        
        if (ref $self eq 'ARRAY' and $self->[1]) {
                $logfilename = ($self->[1]); 
                 }
        else {
                $logfilename = "DEFAULT_logfile_name";
                }
                
        return $logfilename;
        
}

1;

#! /usr/bin/perl
use strict;
use warnings;

use lib qw(
  Z:/test
);
use test::log;

my $log = test::log->new(
  {
    write_logfile => 0, # 0 => nein, 1 => ja
    logfile_name  => 'logfile',
    logfile_path  => 'C:/WINNT/system32/config',
  }
);

printf "Name des Logfiles: %s\n", $log->logfilename;

__END__

package test::log;
use strict;
use warnings;

$test::log::VERSION = "0.0.2";

my %defaults = (
    write_logfile => 0,  # 0 => nein, 1 => ja
    logfile_name  => 'DEFAULT_logfile_name',
    logfile_path  => 'C:/WINNT/system32/config',
);


sub new {
  my ( $class, $ref ) = @_;
  my $self;

  if ( ref( $ref ) ne 'HASH' ) {
    die "Please provide a hash reference as argument!\n";
  }

  # uebernehme die definierten Defaults und die Inhalte der übergebenen 
  # Hash-Referenz; diese Inhalte ueberlagern ggfs. die Defaults, sodass in 
  # $self die Defaults für Parameter gelten, die nicht mitgegeben wurden
  $self = { %defaults, %$ref };

  bless $self, ref( $class ) || $class;

  return $self;
}

sub logfilename {
  my ( $self, @args ) = @_;

  return $self->{logfile_name} if exists $self->{logfile_name};

  return undef;
}

1;

Use of uninitialized value in printf at test_log2.pl line 18.
Name des Logfiles:

sub new {
        my $this=shift;
        my $class=ref($this) || $this;
        my $self= {};

        #class attributes
        $self->{attr1}=undef;

        #bless the object
        bless($self,$class);

        #return the reference to the blesses object
        return($self);
}