use strict;
use warnings;

package Config::Once;

use Config::Auto;

sub init {
        my ($class, $config_path) = @_;
        ...
}

sub cfg {
        my ($class, $param) = @_;
        my $config_varname = $class . '::Config';
        no strict 'refs';
        return $$config_varname->{$param} if (defined $param);
        return $$config_varname;
}

1;

##</code><code>##

Config::Auto->init($config_path);

##</code><code>##

Config::Auto->cfg('varname');