IPC::Semaphore
Section: Perl Programmers Reference Guide (3)
Updated: perl 5.005, patch 02
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NAME
IPC::Semaphore - SysV Semaphore IPC object class
SYNOPSIS
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;
DESCRIPTION
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
- *
-
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 processed waiting for the semaphore SEM to
become greater than it's 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 processed 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 the semop manpage 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 (oly 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 you system documentation.
uid
gid
cuid
cgid
mode
ctime
otime
nsems
SEE ALSO
the IPC::SysV manpage the Class::Struct manpage the semget manpage the semctl manpage the semop manpage
AUTHOR
Graham Barr <gbarr@pobox.com>
COPYRIGHT
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.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- METHODS
-
- SEE ALSO
-
- AUTHOR
-
- COPYRIGHT
-
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