#!/usr/bin/perl
use strict;
use warnings;
use Storable qw(retrieve store retrieve_fd store_fd);
use Fcntl qw(:flock);

my $file='/tmp/storable_test';
my %data = (
    item => 'Here I am',
);
store(\%data, $file);
#=====

# open & lock file
open(my $fh, '+<', $file);
flock($fh, LOCK_EX);

# get data, amend, put back
my $data = retrieve_fd(\*$fh);
print 'item: ', $data->{item},$/;

delete($data->{item});

print 'gone (error as expected): ', $data->{item},$/;

truncate $fh, 0; # <- *** WAS MISSING THIS ***
seek $fh, 0, 0;  # <- *** WAS MISSING THIS ***

store_fd($data, \*$fh);
close($fh);

#======
# now reload from the file
my $check_data = retrieve($file);
print 'why is this here? ', $check_data->{item},$/;