use strict;
use GDBM_File;
use Carp qw(confess);
use Fcntl qw(:flock);

my %term_doc_count;
my $db = tie(%term_doc_count, 'GDBM_File', "resources/term_docCount", GDBM_READER, 0666)
    or confess("Unable to tie GDBM db : $!");

my $fd = $db->fd();
open(DB_FH, "<&=$fd") or confess "Could not open file: $!";
unless (flock (DB_FH, LOCK_SH | LOCK_NB)) {
       print "$$: CONTENTION; can't read during write update!
                  Waiting for read lock ($!) ....        \n";
       unless (flock (DB_FH, LOCK_SH)) { die "flock: $!" }
   }
print "$$: Read lock granted\n";
untie %term_doc_count;
close(DB_FH);
flock(DB_FH, LOCK_UN);