man IPC::Semaphore () - SysV Semaphore IPC object class

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

A class providing an object based interface to SysV IPC semaphores.

METHODS

new ( KEY , NSEMS , FLAGS )
Create a new semaphore set associated with CWKEY. CWNSEMS is the number of semaphores in the set. A new set is created if
*
CWKEY is equal to CWIPC_PRIVATE
*
CWKEY does not already have a semaphore identifier associated with it, and CWCIFLAGSCW & IPC_CREAT is true. On creation of a new semaphore set CWFLAGS 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 CWSEM to become greater than its current value
getpid ( SEM )
Returns the process id of the last process that performed an operation on the semaphore CWSEM.
getval ( SEM )
Returns the current value of the semaphore CWSEM.
getzcnt ( SEM )
Returns the number of processes waiting for the semaphore CWSEM to become zero.
id
Returns the system identifier for the semaphore set.
op ( OPLIST )
CWOPLIST is a list of operations to pass to CWsemop. CWOPLIST 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 ...] )
CWset will set the following values of the CWstat structure associated with the semaphore set. 
    uid
    gid
    mode (only the permission bits)
CWset accepts either a stat object, as returned by the CWstat method, or a list of name-value pairs.
setall ( VALUES )
Sets all values in the semaphore set to those given on the CWVALUES list. CWVALUES must contain the correct number of values.
setval ( N , VALUE )
Set the CWNth value in the semaphore set to CWVALUE
stat
Returns an object of type CWIPC::Semaphore::stat which is a sub-class of CWClass::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

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.