sub write_array_1{
  my $file = shift;
  
  my $r_array = \@_;
  
  open FILE, ">$file" or die "failed to open $file ($!)";
  print FILE @$r_array;
  close FILE;
}

##</code><code>##

use strict;
use warnings;
use Benchmark;

sub write_array_1{
  my $file = shift;
  
  my $r_array = \@_;
  
  $_++ foreach @$r_array;
}

sub write_array_2{
  my $file = shift;
  
  my $r_array = shift;
  
  $_++ foreach @$r_array;
}

sub write_array_31{
  my $file = shift;
  
  my @array = @_;
  
  $_++ foreach @array;
}


my @array = ( 1..100000 );

my $filename = 'C:\users\jake\testing\arrayref.dat';

timethese(30, {
        'Pass by ref transparently' => sub {write_array_1( $filename . 1, @array );},
        'Pass by ref explicitly'    => sub {write_array_2( $filename . 2, \@array );},
        'Pass by value'             => sub {write_array_3( $filename . 3, @array );},
    });


Benchmark: timing 30 iterations of Pass by ref explicitly, Pass by ref transparently, Pass by value...
Pass by ref explicitly:  2 wallclock secs ( 1.84 usr +  0.00 sys =  1.84 CPU) @ 16.27/s (n=30)
Pass by ref transparently:  3 wallclock secs ( 2.94 usr +  0.00 sys =  2.94 CPU) @ 10.21/s (n=30)
Pass by value:  4 wallclock secs ( 4.42 usr +  0.02 sys =  4.44 CPU) @  6.76/s (n=30)