use CGI::Carp qw(fatalsToBrowser set_message);
BEGIN {
    sub handle_errors {
        my $msg = shift;
        print "<h1>Oh gosh</h1>";
        print "<p>Got an error: $msg</p>";
    }
    set_message(\&handle_errors);
}

##</code><code>##

use CGI;
use CGI::Carp qw(fatalsToBrowser);
BEGIN {
    sub carp_error {
        my $error_message = shift;
        my $q = new CGI;
        print $q->start_html( "Error" ),
              $q->h1( "Error" ),
              $q->p( "Sorry, the following error occurred: " ),
              $q->p( $q->i( $error_message ) ),
              $q->end_html;
    }
    CGI::Carp::set_message( \&carp_error );
}

##</code><code>##

#!/usr/bin/perl -T
use strict;
use warnings;
use CGI qw( -headers_once );
use CGI::Carp qw( fatalsToBrowser );
my $q;               # The CGI object will get file scope.
BEGIN {
    $q = new CGI;    # Construct the CGI object
                     # within the BEGIN block.
    sub carp_error {
        my $error_message = shift;
        print $q->header( "text/html" ),
              $q->start_html( "Error" ),
              $q->h1( "Error" ),
              $q->p( "Sorry, the following error occurred: " ),
              $q->p( $q->i( $error_message ) ),
              $q->end_html;
    }
    CGI::Carp::set_message( \&carp_error );
}