I would create a module creating the cgi object and then <it>use</it> it in all modules requiring the cgi object. For instance something along the lines of:

package CGI::Instance;

use strict;
use CGI;
use Exporter   ();
use vars       qw(@ISA @EXPORT $cgi);
@ISA         = qw(Exporter);
@EXPORT      = qw( $cgi );

$cgi = new CGI;

1;
[download]

And then in A.pm and B.pm put a use CGI::Instance. This way, $cgi is only created once and is available both in A and in B.

Best regards

Antonio Bellezza