What happens is Storable can not convert Perl code, which is what this MLDBM::Sync lock object is, into something it can store on disk. I haven't resolved the issue yet. I'm trying to use Data::Dumper, since it can work with Perl code, or, more precisely, it stores objects by converting them to Perl code.

You're trying to store the MLDBM::Sync object inside of MLDBM::Sync? Don't do that! Here's the sort of thing I had in mind:

package Calendar;

# constructor
sub new {
    my $class = shift;
    my %args = @_;
    
    my $calendar = {};
    my %data;

    my $sync_dbm_obj = tie(%data, 'MLDBM::Sync', "$args{DIR}\\$arg
+s{year}.db", O_CREAT|O_RDWR, 0640) 
                        or die "can't open tie to $args{year}.db: $!";
    
    $calendar->{'data'} = \%data;

    # if just created, initialize hash with default values
    if( !$calendar->{data}{months} ) {

        $sync_dbm_obj->Lock;

        $calendar->{data}{year} = $args{year};
        $calendar->{data}{months} = {};
        my $aref = $calendar->{data}{months};
        foreach my $month (1..12) {
            $aref->{$month} = _init_days($calendar->{data}{year}, $mon
+th);
        }
        $calendar->{data}{months} = $aref;

        $sync_dbm_obj->UnLock;
    }
    
    return bless $calendar, $class;
}
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When you need access to the MLDBM::Sync object you just say my $sync_dbm_obj = tied $calendar->{data} to get it.

Of course this is not an OO approach. If you really want to use OO, you should make accessor methods for $calendar->months(), $calendar->year(), etc. instead of just using a tied hash.

Perhaps you're running into the same issue that was being addressed over here. (or related anyway). The jist is you should see about upgrading your Storable and maybe perl itself.

__SIG__
printf "You are here %08x\n", unpack "L!", unpack "P4", pack "L!", B::
+svref_2object(sub{})->OUTSIDE
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