Genezzo::Contrib::Clustered::GLock::GLockUR - Unix record locking implementation for Genezzo
my $lockid = ur_lock($name, $shared, $blocking); my $success = ur_promote($name, $lockid, $blocking); my $success = ur_unlock($lockid);
Provides Perl wrappers to basic Unix record fcntl C functions.
Locks lock with name NAME. Shared if SHARED=1, otherwise exclusive. Blocking if BLOCKING=1, otherwise returns immediately. Returns lockid,or 0 for failure.
Promotes lock with name NAME and lockid LOCKID to exclusive mode. Returns 1 for success, or 0 for failure.
Demotes lock with name NAME and lockid LOCKID to shared mode. Returns 1 for success, or 0 for failure.
Releases lock with lockid LOCKID. Returns 1 for success, 0 for failure.
ur_lock, ur_promote, ur_unlock
Relies on Perl Inline::C module. Currently terminates program when deadlock detected.
Inline code is installed in directory /Inline, so it can be used with Apache.
A file /tmp/genezzo.lock is created. It must be writeable by the accessing processes. The undo file should probably be used for locking instead.
All processes must be owned by the same user; otherwise kill SIGUSR2 signals will be blocked.
Eric Rollins, email@example.com
Copyright (c) 2005 Eric Rollins. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Address bug reports and comments to firstname.lastname@example.org
For more information, please visit the Genezzo homepage at http://www.genezzo.com