D:\>perl -V:useperlio
$Config::AUTOLOAD: Config::fetch_string
$INC{$config_heavy}: E:/Perl817/lib/Config_heavy.pl
$Config::AUTOLOAD: Config::launcher
$INC{$config_heavy}: E:/Perl817/lib/Config_heavy.pl
$Config::AUTOLOAD: Config::launcher
$INC{$config_heavy}: E:/Perl817/lib/Config_heavy.pl
&Config::AUTOLOAD failed on Config::launcher at E:/Perl817/lib/Config.pm line 73.

##</code><code>##

    open(RD, "<", $INC{$config_heavy})
        or die "Can't open $INC{$config_heavy}: $!";
    while(<RD>) {print $_ if $_ =~ /launcher/}
    close(RD) or die "Can't close $INC{$config_heavy}: $!";

##</code><code>##

D:\>perl -V:useperlio
sub launcher {
    print "\n\nrunning launcher()\n\n";
$Config::AUTOLOAD: Config::fetch_string
$INC{$config_heavy}: E:/Perl817/lib/Config_heavy.pl
sub launcher {
    print "\n\nrunning launcher()\n\n";
$Config::AUTOLOAD: Config::launcher
$INC{$config_heavy}: E:/Perl817/lib/Config_heavy.pl
sub launcher {
    print "\n\nrunning launcher()\n\n";
$Config::AUTOLOAD: Config::launcher
$INC{$config_heavy}: E:/Perl817/lib/Config_heavy.pl
&Config::AUTOLOAD failed on Config::launcher at E:/Perl817/lib/Config.pm line 77.