298 lines
5.6 KiB
Perl
298 lines
5.6 KiB
Perl
# IPC::Semaphore
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#
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# Copyright (c) 1997 Graham Barr <gbarr@pobox.com>. All rights reserved.
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# This program is free software; you can redistribute it and/or
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# modify it under the same terms as Perl itself.
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package IPC::Semaphore;
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use IPC::SysV qw(GETNCNT GETZCNT GETVAL SETVAL GETPID GETALL SETALL
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IPC_STAT IPC_SET IPC_RMID);
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use strict;
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use vars qw($VERSION);
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use Carp;
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$VERSION = "1.00";
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{
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package IPC::Semaphore::stat;
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use Class::Struct qw(struct);
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struct 'IPC::Semaphore::stat' => [
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uid => '$',
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gid => '$',
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cuid => '$',
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cgid => '$',
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mode => '$',
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ctime => '$',
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otime => '$',
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nsems => '$',
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];
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}
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sub new {
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@_ == 4 || croak 'new ' . __PACKAGE__ . '( KEY, NSEMS, FLAGS )';
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my $class = shift;
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my $id = semget($_[0],$_[1],$_[2]);
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defined($id)
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? bless \$id, $class
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: undef;
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}
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sub id {
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my $self = shift;
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$$self;
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}
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sub remove {
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my $self = shift;
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(semctl($$self,0,IPC_RMID,0), undef $$self)[0];
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}
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sub getncnt {
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@_ == 2 || croak '$sem->getncnt( SEM )';
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my $self = shift;
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my $sem = shift;
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my $v = semctl($$self,$sem,GETNCNT,0);
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$v ? 0 + $v : undef;
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}
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sub getzcnt {
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@_ == 2 || croak '$sem->getzcnt( SEM )';
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my $self = shift;
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my $sem = shift;
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my $v = semctl($$self,$sem,GETZCNT,0);
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$v ? 0 + $v : undef;
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}
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sub getval {
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@_ == 2 || croak '$sem->getval( SEM )';
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my $self = shift;
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my $sem = shift;
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my $v = semctl($$self,$sem,GETVAL,0);
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$v ? 0 + $v : undef;
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}
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sub getpid {
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@_ == 2 || croak '$sem->getpid( SEM )';
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my $self = shift;
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my $sem = shift;
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my $v = semctl($$self,$sem,GETPID,0);
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$v ? 0 + $v : undef;
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}
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sub op {
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@_ >= 4 || croak '$sem->op( OPLIST )';
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my $self = shift;
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croak 'Bad arg count' if @_ % 3;
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my $data = pack("s*",@_);
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semop($$self,$data);
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}
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sub stat {
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my $self = shift;
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my $data = "";
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semctl($$self,0,IPC_STAT,$data)
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or return undef;
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IPC::Semaphore::stat->new->unpack($data);
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}
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sub set {
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my $self = shift;
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my $ds;
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if(@_ == 1) {
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$ds = shift;
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}
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else {
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croak 'Bad arg count' if @_ % 2;
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my %arg = @_;
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my $ds = $self->stat
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or return undef;
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my($key,$val);
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$ds->$key($val)
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while(($key,$val) = each %arg);
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}
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my $v = semctl($$self,0,IPC_SET,$ds->pack);
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$v ? 0 + $v : undef;
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}
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sub getall {
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my $self = shift;
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my $data = "";
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semctl($$self,0,GETALL,$data)
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or return ();
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(unpack("s*",$data));
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}
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sub setall {
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my $self = shift;
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my $data = pack("s*",@_);
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semctl($$self,0,SETALL,$data);
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}
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sub setval {
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@_ == 3 || croak '$sem->setval( SEM, VAL )';
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my $self = shift;
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my $sem = shift;
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my $val = shift;
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semctl($$self,$sem,SETVAL,$val);
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}
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1;
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__END__
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=head1 NAME
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IPC::Semaphore - SysV Semaphore IPC object class
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=head1 SYNOPSIS
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use IPC::SysV qw(IPC_PRIVATE S_IRWXU IPC_CREAT);
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use IPC::Semaphore;
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$sem = new IPC::Semaphore(IPC_PRIVATE, 10, S_IRWXU | IPC_CREAT);
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$sem->setall( (0) x 10);
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@sem = $sem->getall;
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$ncnt = $sem->getncnt;
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$zcnt = $sem->getzcnt;
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$ds = $sem->stat;
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$sem->remove;
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=head1 DESCRIPTION
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=head1 METHODS
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=over 4
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=item new ( KEY , NSEMS , FLAGS )
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Create a new semaphore set associated with C<KEY>. C<NSEMS> is the number
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of semaphores in the set. A new set is created if
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=over 4
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=item *
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C<KEY> is equal to C<IPC_PRIVATE>
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=item *
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C<KEY> does not already have a semaphore identifier
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associated with it, and C<I<FLAGS> & IPC_CREAT> is true.
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=back
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On creation of a new semaphore set C<FLAGS> is used to set the
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permissions.
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=item getall
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Returns the values of the semaphore set as an array.
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=item getncnt ( SEM )
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Returns the number of processed waiting for the semaphore C<SEM> to
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become greater than it's current value
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=item getpid ( SEM )
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Returns the process id of the last process that performed an operation
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on the semaphore C<SEM>.
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=item getval ( SEM )
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Returns the current value of the semaphore C<SEM>.
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=item getzcnt ( SEM )
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Returns the number of processed waiting for the semaphore C<SEM> to
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become zero.
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=item id
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Returns the system identifier for the semaphore set.
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=item op ( OPLIST )
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C<OPLIST> is a list of operations to pass to C<semop>. C<OPLIST> is
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a concatenation of smaller lists, each which has three values. The
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first is the semaphore number, the second is the operation and the last
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is a flags value. See L<semop> for more details. For example
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$sem->op(
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0, -1, IPC_NOWAIT,
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1, 1, IPC_NOWAIT
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);
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=item remove
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Remove and destroy the semaphore set from the system.
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=item set ( STAT )
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=item set ( NAME => VALUE [, NAME => VALUE ...] )
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C<set> will set the following values of the C<stat> structure associated
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with the semaphore set.
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uid
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gid
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mode (oly the permission bits)
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C<set> accepts either a stat object, as returned by the C<stat> method,
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or a list of I<name>-I<value> pairs.
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=item setall ( VALUES )
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Sets all values in the semaphore set to those given on the C<VALUES> list.
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C<VALUES> must contain the correct number of values.
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=item setval ( N , VALUE )
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Set the C<N>th value in the semaphore set to C<VALUE>
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=item stat
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Returns an object of type C<IPC::Semaphore::stat> which is a sub-class of
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C<Class::Struct>. It provides the following fields. For a description
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of these fields see you system documentation.
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uid
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gid
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cuid
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cgid
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mode
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ctime
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otime
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nsems
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=back
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=head1 SEE ALSO
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L<IPC::SysV> L<Class::Struct> L<semget> L<semctl> L<semop>
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=head1 AUTHOR
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Graham Barr <gbarr@pobox.com>
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=head1 COPYRIGHT
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Copyright (c) 1997 Graham Barr. All rights reserved.
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This program is free software; you can redistribute it and/or modify it
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under the same terms as Perl itself.
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=cut
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