NAME

IPC::SysV::Msg - wrapper functions for the msg* functions

SYNOPSIS

use IPC::SysV::Msg qw(msg_create_queue ...);

$key = 55;
$qid = msg_get_queue_id($key);
$qid = msg_create_queue($key,'rw-rw--w-');
msg_add_to_queue($qid,$type,$string,$nowait);
$ds = msg_get_queue_status($qid);
$ds->set_uid_gid_mode_qbytes($uid, $gid, $mode, $qbytes);
msg_set_queue_status($qid,$ds);
($type,$str) = msg_remove_from_queue($qid,$size,$type,$nowait,$noerror);
msg_remove_queue_id($qid);

DESCRIPTION

This module provides wrappers to msgctl, msgrcv, msgsnd and msgget. Where undef is returned, you can check the $! status for the various error types.

msg_get_queue_id KEY

Wraps the msgget function for accessing message queue ids. Returns the msgqid (a number) of the queue data structure to which KEY is already associated. Returns undef if that queue does not exist.

msg_create_queue KEY, MODE

Wraps the msgget function for creating message queues. It takes a KEY which should be a positive integer, and a MODE which should be 9 bit mode or a string in the format: 'RW-RW-RW-' where R is 'r' or '-', W is 'w' or '-' .

It returns the msgqid (a number) of the queue data structure created, or undef if the queue could not be created. Specifically, this will return undef if you try to create a queue on a key which is already associated to an existing queue.

msg_add_to_queue QID, TYPE, STRING [,NOWAIT]

Wraps msgsnd. Adds a message to the queue specified by QID. The message added contains the type TYPE and the string STRING. If NOWAIT is true, then the msgsnd will not block, otherwise it will until the message could be added to the queue.

msg_remove_from_queue QID, SIZE, TYPE, [,NOWAIT [,NOERROR] ]

Wraps msgrcv. Tries to remove a message from the queue specified by QID. If TYPE is 0, then the first message is removed; if TYPE is greater than 0, the first message of type TYPE is removed; If TYPE is less than 0, the first message of the lowest type that is less than or equal to the absolute value of TYPE is removed. The call is blocked until a message is available unless NOWAIT is true. The removed message string is truncated to size SIZE if it is larger than SIZE and NOERROR is true, otherwise the call fails (empty array returned, error status in $!). On success, returns an array with two values, the type of the message removed, and the string it contained.

msg_get_queue_status QID

Wraps msgctl. Returns an IPC::SysV::Msg::DS object holding the current status of the of the queue.

msg_set_queue_status QID, DS

Wraps msgctl. Sets the queue status using the IPC::SysV::Msg::DS object DS.

msg_remove_queue_id QID

Wraps msgctl. Removes the given by queue id QID from the system.

Jack Shirazi

This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

Version 1.0

Base version.