I am working on a unix system (FreeBSD), and thanks for the semaphore pointer (further explained
here).
I guess I'm just surprised that the above doesn't work. As I test and test and re-test I am completely duped that even this simple code doesn't work...
#!/usr/bin/perl -w
# start with no existing giant.db file
use strict;
use Fcntl qw(:DEFAULT :flock);
use Storable qw(store_fd fd_retrieve retrieve);
use Data::Dumper;
$Data::Dumper::Deepcopy=1;
$Data::Dumper::Purity=1;
$Data::Dumper::Sortkeys=1;
my %data = ( 1 => 'FEE', 2 => 'FYE',
3 => 'FOH', 4 => 'FUM', );
sysopen(*DB, "giant.db", O_RDWR|O_CREAT, 0666) or die("sysopen: $!\n")
+;
flock(*DB, LOCK_EX) or die("flock: $!\n");
my $hashref = fd_retrieve(*DB);
# modify the data, do work, etc..
$hashref->{$_} = $data{$_} for sort keys %data;
store_fd($hashref, *DB) or die("store_fd: $!\n");
truncate(*DB, tell(*DB));
close(*DB);
I'm totally spent and frustrated. Does anyone have any idea why this doesn't work? I must be missing something. I'm just trying to block access to a file while I change it. The above SHOULD work, shouldn't it?....shouldn't it?....please?
Thanks