in reply to Config::Std requirements question

You're looking at different documentation than I am, then:

use Scalar::Util qw(blessed dualvar isweak readonly refaddr reftype ta
+inted
                        weaken isvstring looks_like_number set_prototy
+pe);

[download]
refaddr EXPR

If EXPR evaluates to a reference the internal memory address of the referenced value is returned. Otherwise undef is returned.

    $addr = refaddr "string";           # undef
    $addr = refaddr \$var;              # eg 12345678
    $addr = refaddr [];                 # eg 23456784

    $obj  = bless {}, "Foo";
    $addr = refaddr $obj;               # eg 88123488

[download]

I'd say, install a version of Scalar::Util after version 1.09 or so.

In Section Seekers of Perl Wisdom