You can only pass a list of scalars to a subroutine. Arrays will automatically get flattened into a list:

mysub(@a);
[download]

is the same thing as

mysub($a[0], $a[1], $a[2], ...);
[download]

For example,

sub sortArray {
   return sort @_;
}

my @a = ('e', 'd', 'c', 'b', 'a');
my @sorted = sortArray(@a);
print("@sorted\n");  # a b c d e

# Same thing.
my @sorted = sortArray('e', 'd', 'c', 'b', 'a');
print("@sorted\n");  # a b c d e
[download]

If you want to modify the array, you can pass a reference to the array to the subroutine.

sub sortArray {
   my ($ar) = @_;
   @$ar = sort @$ar;
}

my @a = qw( e d c b a );
sortArray(\@a);
print("@a\n");  # a b c d e
[download]

Some references on references:

• perlref
• Dereferencing Syntax
• References Quick Reference

Update: Added reference links.
Update: Converted first example to sort its arguments.

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