http://www.perlmonks.org?node_id=155866


in reply to Passing references to a sub.

The other use of references is when you need to pass two arrays (or a hash and an array) into a sub.
Consider: 
my @array1 = ("foo", "foo1", "foo2");
my @array2 = ("bar", "bar1", "bar2");

print_data(@array1, @array2);

sub print_data {
    @array1 = @_; #array1 gets all of @_
    @array2 = @_; #array2 also gets all of @_
}

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vs 
print_data(\@array1, \@array2);

sub print_data {
    my @data1 = @{$_[0]}; #dereferences first array into @data1
    my @data2 = @{$_[1]}; #dereferences second array into @data2
}

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The second version is more often than not what you actually want.

In Section Seekers of Perl Wisdom