Perl modify arguments by reference

modifyByReference.pl

#!/usr/bin/perl -w

use strict;
use Data::Dumper;

sub t1 {
	my ($v) = @_;
	
	$$v = {hey => "you", there => 'me'};
}

my $v = {some => 'value'};

print Dumper($v);
#$VAR1 = {
#          'some' => 'value'
#        };

t1(\$v);

print Dumper($v);
#$VAR1 = {
#          'there' => 'me',
#          'hey' => 'you'
#        };