Perl doesn't talk about "pointers", it uses "references". It doesn't have multi-dimensional arrays, Perl has arrays of references (each of which may be to an array). Perl always passes parameters to subs by reference.

If you want a temporary copy of a complicated data structure (that is really pretty much anything using references) you need to make a "deep copy". Perl doesn't have an inbuilt way to do that, but there are a number of modules that do the trick. Most common is Storable. Consider:

use strict;
use warnings;
use Storable;
use Data::Dump::Streamer;

my $ref = [
    {a => 1, b => 2, c => 3},
    [1, 2, 3],
    {x => [4, 5, 6], y => [7, 8, 9]},
    ];

my $org = Dump ($ref)->Out ();

mangle ($ref);

my $after = Dump ($ref)->Out ();

print "Structure unmangled" if "$org" eq "$after";


sub mangle {
    my $cloned = Storable::dclone ($_[0]);
    
    $cloned->[0]{a} = 6;
    $cloned->[1][0] = 23;
    
    Dump $cloned;
}
[download]

Prints:

$ARRAY1 = [
            {
              a => 6,
              b => 2,
              c => 3
            },
            [
              23,
              2,
              3
            ],
            {
              x => [
                     4,
                     5,
                     6
                   ],
              y => [
                     7,
                     8,
                     9
                   ]
            }
          ];
Structure unmangled
[download]