picard:~ [14:15:22]$ cat inc.pl
#!/usr/bin/perl

use strict;
use warnings;
use Devel::Peek 'Dump';

sub inc { $_++ for @_; Dump $_[0] }

my @array;
$array[1]=666;
inc @array;
Dump $array[0];

__END__
picard:~ [14:15:35]$ ./inc.pl
SV = PVNV(0x8152908) at 0x819ab20
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 1
  NV = 0
  PV = 0
SV = NULL(0x0) at 0x819ab20
  REFCNT = 1
  FLAGS = ()