Some misunderstandings:

my $ar = qw/ foo bar baz /;

In the line above, you're assigning a list in scalar context. You're going to get the last element of that list (baz) assigned to $ar.

func(\@ar);

That will throw a warning under strict because you declared a scalar ($ar), not an array (@ar).

my $ar = @_;

Now you're accessing an array in scalar context. This will result in $ar being set the the number of elements in @_. Here's a quick demonstration:

$ perl -e 'sub aa {my $a = @_;print $a}; aa(qw(foo bar baz))'
3
[download]

I realie those seem tricky and frankly, it's often a matter of memorizing how those things behave.

Cheers,
Ovid

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