What's the best Perl practice for returning hashes from functions?

Question

I am mulling over a best practice for passing hash references for return data to/from functions.

On the one hand, it seems intuitive to pass only input values to a fun

Answer 1

Just return the reference. There is no need to dereference the whole hash like you are doing in your examples:

my $result = some_function_that_returns_a_hashref;
say "Foo is ", $result->{foo};
say $_, " => ", $result->{$_} for keys %$result;

etc.

I have never seen anyone pass in empty references to hold the result. This is Perl, not C.