Perl "scalar" function returning "1" on an empty array

Question

The following Perl code will print a "1", however the function test2 really has no legitimate input value. Why does Perl act this way?

test();

sub test {
    my ($var) = @_;

    test2($var);
}

sub test2 {
    my (@array) = @_;
    print scalar @array;
}

Answer 1

test2($var) passes one scalar to test2 ( $var ), so one scalar is assigned to @array by my (@array) = @_; .

The value of the scalar in question ( $var ) is undef , since you assigned "nothing" to $var in my ($var) = @_; .

Maybe you want test2(@_) (passes the zero scalars in @_ ) instead of test2($var) (passes the one scalar $var )?

Answer 2

Inside test , $var is set to undef by the assignment. So your call to test2 passes a list with one element, undef .