IPC::Semaphore(3)Perl Programmers Reference GuidIPC::Semaphore(3)NAMEIPC::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;
DESCRIPTIONMETHODS
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 iden
tifier 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 per
formed 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 "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 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.
2001-02-22 perl v5.6.1 IPC::Semaphore(3)
