use tahash;
my %hash = (
              "Jan" => 1,
              "Feb" => 2,
              "Mar" => 3,
           );
my $val = tie(%hash,"tahash") or die "Can't tie : $!";

##</code><code>##

package tahash;
sub TIEHASH {
   print "<@_ \n>";
   my $class = shift;
   my %hash = @_;
   print "In TIEHASH .... \n";
   return bless(\%hash);
}

##</code><code>##

<tahash
>In TIEHASH ....
The object is destroyed...

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use tahash;
use Data::Dumper (); # just for debugging, remove from production code

my %hash = (
              "Jan" => 1,
              "Feb" => 2,
              "Mar" => 3,
           );

my $val = tie(%hash,"tahash") or die "Can't tie : $!";
print Data::Dumper->new([$val],['val'])->Dump(),"\n";
print Data::Dumper->new([\%hash],['*hash'])->Dump(),"\n";

##</code><code>##

package tahash;

use strict;
use warnings;
use Data::Dumper (); # just for debugging, remove from production code

sub TIEHASH {
	print Data::Dumper->new([\@_],['*_'])->Dump(),"\n";
	my $class = shift;
	my %hash = @_;
	print "In TIEHASH .... \n";
	return bless(\%hash);
}


sub DESTROY {
	print "The object is destroyed...\n";
}

1;

##</code><code>##

X:\>perl 1221948.pl
@_ = (
       'tahash'
     );

In TIEHASH ....
$val = bless( {}, 'tahash' );

Can't locate object method "FIRSTKEY" via package "tahash" at C:/strawberry/perl
/lib/Data/Dumper.pm line 190.
The object is destroyed...

X:\>

##</code><code>##

package tahash;

use strict;
use warnings;
use Data::Dumper (); # just for debugging, remove from production code

# For historic reasons, the Tie::StdHash class is hidden in Tie::Hash.
# So you have to load Tie::Hash instead of Tie::StdHash and set @INC manually.
# Otherwise, you could simply do this:
#use parent 'Tie::StdHash';

use Tie::Hash ();
our @ISA=qw(Tie::StdHash); 

sub FIRSTKEY {
	my $self=shift;
	print "Hey, someone scans my keys!\n";
	return $self->SUPER::FIRSTKEY(@_);
}

sub DESTROY {
	my $self=shift;
	print "The object is destroyed...\n";
	$self->SUPER::DESTROY();
}

1;

##</code><code>##

X:\>perl 1221949.pl
$val = bless( {}, 'tahash' );

Hey, someone scans my keys!
%hash = ();

The object is destroyed...

X:\>