IPC::Semaphore - SysV Semaphore IPC object class
use IPC::SysV qw(IPC_PRIVATE S_IRWXU IPC_CREAT); use IPC::Semaphore; $sem = new IPC::Semaphore(IPC_PRIVATE, 10, S_IRWXU | IPC_CREAT); $sem->setall( (0) x 10); @sem = $sem->getall; $ncnt = $sem->getncnt; $zcnt = $sem->getzcnt; $ds = $sem->stat; $sem->remove;
Create a new semaphore set associated with KEY
. NSEMS
is the number of semaphores in the set.
A new set is created if
KEY
is equal to IPC_PRIVATE
KEY
does not already have a semaphore identifier associated with it, and <EM>FLAGS</EM> & IPC_CREAT
is true.
On creation of a new semaphore set FLAGS is used to set the permissions.
Returns the values of the semaphore set as an array.
Returns the number of processed waiting for the semaphore SEM
to become greater than it's current value
Returns the process id of the last process that performed an operation on
the semaphore SEM
.
Returns the current value of the semaphore SEM
.
Returns the number of processed waiting for the semaphore SEM
to become zero.
Returns the system identifier for the semaphore set.
OPLIST
is a list of operations to pass to semop. OPLIST
is a concatenation of smaller lists, each which has three values. The first
is the semaphore number, the second is the operation and the last is a
flags value. See the semop manpage for more details. For example
$sem->op( 0, -1, IPC_NOWAIT, 1, 1, IPC_NOWAIT );
Remove and destroy the semaphore set from the system.
set will set the following values of the stat structure associated with the semaphore set.
uid gid mode (oly the permission bits)
set accepts either a stat object, as returned by the stat method, or a list of name-value pairs.
Sets all values in the semaphore set to those given on the VALUES
list.
VALUES
must contain the correct number of values.
Set the N
th value in the semaphore set to VALUE
Returns an object of type IPC::Semaphore::stat
which is a sub-class of
Class::Struct
. It provides the following fields. For a description of these fields see
you system documentation.
uid gid cuid cgid mode ctime otime nsems
SysV Struct the semget manpage the semctl manpage the semop manpage
Graham Barr <gbarr@pobox.com>
Copyright (c) 1997 Graham Barr. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.