IPC::Semaphore(3)

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
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.
Returns the values of the semaphore set as an array. Returns the number of processed waiting for the semaphore "SEM" to become greater than it's current value Returns the process id of the last process that performed an operation on the semaphore "SEM". Returns the current value of the semaphore "SEM". Returns the number of processed waiting for the semaphore "SEM" to become zero. Returns the system identifier for the semaphore set. "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 and destroy the semaphore set from the system. "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. Sets all values in the semaphore set to those given on the "VALUES" list. "VALUES" must contain the correct number of values. Set the "N"th value in the semaphore set to "VALUE" 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.