GNU/Linux |
CentOS 5.4 |
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IPC::Semaphore(3pm) |
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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;
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 "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
IPC::SysV Class::Struct semget semctl semop
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.
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IPC::Semaphore(3pm) | ![]() |