sub print_variable {
    local *print_variable = $_[0];
    my $name = $print_variable;
    for (keys %::){
        next if /^print_variable$/;
        print "$_ = $name\n" 
            if *{$::{$_}}{SCALAR} eq  *{$::{print_variable}}{SCALAR};
    }
}
$firstname = "Edward";
$var = 1;
print_variable( *firstname );
print_variable( *var );
__END__
firstname = Edward
var = 1

##</code><code>##

$firstname = "Edward";
*surname = *firstname;
print_variable( *firstname );
__END__
firstname = Edward
surname = Edward