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;
A class providing an object based interface to SysV IPC semaphores.
new ( KEY , NSEMS , FLAGS ) 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 FLAGS & IPC_CREAT is true.
On creation of a new semaphore set FLAGS is used to set the permissions.
getall Returns the values of the semaphore set as an array. getncnt ( SEM ) Returns the number of processes waiting for the semaphore SEM to become greater than its current value getpid ( SEM ) Returns the process id of the last process that performed an operation on the semaphore SEM. getval ( SEM ) Returns the current value of the semaphore SEM. getzcnt ( SEM ) Returns the number of processes waiting for the semaphore SEM to become zero. id Returns the system identifier for the semaphore set. op ( OPLIST ) 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 semop for more details. For example
$sem->op( 0, -1, IPC_NOWAIT, 1, 1, IPC_NOWAIT );
remove Remove and destroy the semaphore set from the system. set ( STAT ) set ( NAME => VALUE [, NAME => VALUE ...] ) set will set the following values of the stat structure associated with the semaphore set.
uid gid mode (only the permission bits)
set accepts either a stat object, as returned by the stat method, or a list of name-value pairs.
setall ( VALUES ) Sets all values in the semaphore set to those given on the VALUES list. VALUES must contain the correct number of values. setval ( N , VALUE ) Set the Nth value in the semaphore set to VALUE stat 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 your system documentation.
uid gid cuid cgid mode ctime otime nsems
IPC::SysV Class::Struct semget semctl semop
Graham Barr <firstname.lastname@example.org>
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.
|perl v5.8.8||IPC::Semaphore (3pm)||2001-09-21|