use strict;
use vars qw(%h1 %h2);

sub get_statm_info {
  my $error = '';
  my $ref = {};

  if( ! open(_INFO,"</proc/$_[0]/statm") ){
    $error = "Couldn't open /proc/$_[0]/statm [$!]";
    return $ref;
  }
  my @info = split(/\s+/,<_INFO>);
  close(_INFO);

  ### these are all the props (skip some)
  # size resident shared trs lrs drs dt
  ###

  ### get the important ones
  $ref = {size     => $info[0] * 4,
          resident => $info[1] * 4,
          shared   => $info[2] * 4};

  return $ref;
}

# Double hash case.
%h1 = map { $_, 16 } 1..10000;
%h2 = map { $_, 20 } 1..10000;
# Single hash of arrays.
#%h1 = map { $_, [16,20] } 1..10000;
my $ref = get_statm_info($$);
print $ref->{size},"\n";
print $ref->{resident},"\n";
print $ref->{shared},"\n";