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IPC::Semaphore(3pm) Perl Programmers Reference Guide IPC::Semaphore(3pm) NAME
IPC::Semaphore - SysV Semaphore IPC object class SYNOPSIS
use IPC::SysV qw(IPC_PRIVATE S_IRUSR S_IWUSR IPC_CREAT); use IPC::Semaphore; $sem = IPC::Semaphore->new(IPC_PRIVATE, 10, S_IRUSR | S_IWUSR | IPC_CREAT); $sem->setall( (0) x 10); @sem = $sem->getall; $ncnt = $sem->getncnt; $zcnt = $sem->getzcnt; $ds = $sem->stat; $sem->remove; DESCRIPTION
A class providing an object based interface to SysV IPC semaphores. METHODS
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 o "KEY" is equal to "IPC_PRIVATE" o "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. Be careful not to set any flags that the Sys V IPC implementation does not allow: in some systems setting execute bits makes the operations fail. 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 "N"th 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 SEE ALSO
IPC::SysV, Class::Struct, semget, semctl, semop AUTHORS
Graham Barr <gbarr@pobox.com>, Marcus Holland-Moritz <mhx@cpan.org> COPYRIGHT
Version 2.x, Copyright (C) 2007, Marcus Holland-Moritz. Version 1.x, Copyright (c) 1997, Graham Barr. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. perl v5.12.1 2010-04-26 IPC::Semaphore(3pm)
