title: Perl module error regarding "undefined subroutine"
body: <p>I am trying to use a module called <a href="http://search.cpan.org/perldoc/Math%3a%3aCounting">Math::Counting</a>:</p>
  
  <pre><code>#!/usr/bin/perl 
  
  use strict;
  use warnings;
  use Math::Counting;
  
  my $f = factorial(3);
  print "$f\n";
  </code></pre>
  
  <p>When I run it however,  I get the following error</p>
  
  <pre><code>$ perl UsingModules.pl
  Undefined subroutine &amp;main::factorial called at UsingModules.pl line 8.
  </code></pre>
  
  <p>It seems like the function <code>factorial</code> is not being exported, but why?</p>
  
  <p>When I used the following</p>
  
  <pre><code>my $f = Math::Counting::factorial(3);
  </code></pre>
  
  <p>instead of what was above, it works perfectly fine, but I am curious why the function cannot be exported.</p>
  
  <p>I am using <code>perl</code> v5.10.1 on Cygwin.</p>