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# IPC::Msg.pm
#
# Copyright (c) 1997 Graham Barr <gbarr@pobox.com>. All rights reserved.
# This program is free software; you can redistribute it and/or
# modify it under the same terms as Perl itself.
package IPC::Msg;
use IPC::SysV qw(IPC_STAT IPC_SET IPC_RMID);
use strict;
use vars qw($VERSION);
use Carp;
$VERSION = "1.00";
{
    package IPC::Msg::stat;
    use Class::Struct qw(struct);
    struct 'IPC::Msg::stat' => [
        uid     => '$',
        gid     => '$',
        cuid    => '$',
        cgid    => '$',
        mode    => '$',
        qnum    => '$',
        qbytes  => '$',
        lspid   => '$',
        lrpid   => '$',
        stime   => '$',
        rtime   => '$',
        ctime   => '$',
    ];
}
sub new {
    @_ == 3 || croak 'new IPC::Msg ( KEY , FLAGS )';
    my $class = shift;
    my $id = msgget($_[0],$_[1]);
    defined($id)
        ? bless \$id, $class
        : undef;
}
sub id {
    my $self = shift;
    $$self;
}
sub stat {
    my $self = shift;
    my $data = "";
    msgctl($$self,IPC_STAT,$data) or
        return undef;
    IPC::Msg::stat->new->unpack($data);
}
sub set {
    my $self = shift;
    my $ds;
    if(@_ == 1) {
        $ds = shift;
    }
    else {
        croak 'Bad arg count' if @_ % 2;
        my %arg = @_;
        my $ds = $self->stat
                or return undef;
        my($key,$val);
        $ds->$key($val)
            while(($key,$val) = each %arg);
    }
    msgctl($$self,IPC_SET,$ds->pack);
}
sub remove {
    my $self = shift;
    (msgctl($$self,IPC_RMID,0), undef $$self)[0];
}
sub rcv {
    @_ <= 5 && @_ >= 3 or croak '$msg->rcv( BUF, LEN, TYPE, FLAGS )';
    my $self = shift;
    my $buf = "";
    msgrcv($$self,$buf,$_[1],$_[2] || 0, $_[3] || 0) or
        return;
    my $type;
    ($type,$_[0]) = unpack("L a*",$buf);
    $type;
}
sub snd {
    @_ <= 4 && @_ >= 3 or  croak '$msg->snd( TYPE, BUF, FLAGS )';
    my $self = shift;
    msgsnd($$self,pack("L a*",$_[0],$_[1]), $_[2] || 0);
}
1;
__END__
HideShow 116 lines of Pod
=head1 NAME
IPC::Msg - SysV Msg IPC object class
=head1 SYNOPSIS
    use IPC::SysV qw(IPC_PRIVATE S_IRWXU S_IRWXG S_IRWXO);
    use IPC::Msg;
     
    $msg = new IPC::Msg(IPC_PRIVATE, S_IRWXU | S_IRWXG | S_IRWXO);
     
    $msg->snd(pack("L a*",$msgtype,$msg));
     
    $msg->rcv($buf,256);
     
    $ds = $msg->stat;
     
    $msg->remove;
=head1 DESCRIPTION
=head1 METHODS
=over 4
=item new ( KEY , FLAGS )
Creates a new message queue associated with C<KEY>. A new queue is
created if
=over 4
=item *
C<KEY> is equal to C<IPC_PRIVATE>
=item *
C<KEY> does not already  have  a  message queue
associated with it, and C<I<FLAGS> & IPC_CREAT> is true.
=back
On creation of a new message queue C<FLAGS> is used to set the
permissions.
=item id
Returns the system message queue identifier.
=item rcv ( BUF, LEN [, TYPE [, FLAGS ]] )
Read a message from the queue. Returns the type of the message read. See
L<msgrcv>
=item remove
Remove and destroy the message queue from the system.
=item set ( STAT )
=item set ( NAME => VALUE [, NAME => VALUE ...] )
C<set> will set the following values of the C<stat> structure associated
with the message queue.
    uid
    gid
    mode (oly the permission bits)
    qbytes
C<set> accepts either a stat object, as returned by the C<stat> method,
or a list of I<name>-I<value> pairs.
=item snd ( TYPE, MSG [, FLAGS ] )
Place a message on the queue with the data from C<MSG> and with type C<TYPE>.
See L<msgsnd>.
=item stat
Returns an object of type C<IPC::Msg::stat> which is a sub-class of
C<Class::Struct>. It provides the following fields. For a description
of these fields see you system documentation.
    uid
    gid
    cuid
    cgid
    mode
    qnum
    qbytes
    lspid
    lrpid
    stime
    rtime
    ctime
=back
=head1 SEE ALSO
L<IPC::SysV> L<Class::Struct>
=head1 AUTHOR
Graham Barr <gbarr@pobox.com>
=head1 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.
=cut