I am a bit confused over @ISA. My understanding was that if a function is not declared in a package, Perl will look in other packages listed in @ISA. But when I ran this simple test, it failed: 
#!perl -w
use strict;

package Top;
use Carp;
carp( __PACKAGE__ ." has been loaded" );

package Top::level;
use vars qw( @ISA );
@ISA = ( 'Top' );
carp( __PACKAGE__ ." has been loaded" );

__END__
Output:
Top has been loaded at test.pl line 6
Undefined subroutine &Top::level::carp called at test.pl line 11.

[download]
What am I doing wrong? Or am I just mis-using @ISA?

In reply to A question of inheritance by Adam

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.