90 lines
5.6 KiB
HTML
90 lines
5.6 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html lang="en-us" xml:lang="en-us">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="security" content="public" />
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<meta name="Robots" content="index,follow" />
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<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
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<meta name="DC.Type" content="concept" />
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<meta name="DC.Title" content="Messages" />
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<meta name="abstract" content="A message is a communication sent from one user, program, or procedure to another." />
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<meta name="description" content="A message is a communication sent from one user, program, or procedure to another." />
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<meta name="DC.subject" content="message description, definition, message, predefined, description, predefined message, message, immediate, immediate" />
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<meta name="keywords" content="message description, definition, message, predefined, description, predefined message, message, immediate, immediate" />
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<meta name="DC.Relation" scheme="URI" content="intro.htm" />
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<meta name="DC.Relation" scheme="URI" content="intmsgd.htm" />
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<meta name="DC.Relation" scheme="URI" content="intmsgq.htm" />
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<meta name="DC.Relation" scheme="URI" content="wmsgs.htm" />
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<meta name="DC.Relation" scheme="URI" content="../nls/rbagsglobalmain.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="intmsg" />
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<meta name="DC.Language" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Messages</title>
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</head>
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<body id="intmsg"><a name="intmsg"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Messages</h1>
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<div><p>A message is a communication sent from one user, program, or procedure
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to another.</p>
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<p>System messages can report both status information and error conditions.
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Most data processing systems provide communications between the system and
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the operator to handle errors and other conditions that occur during processing. i5/OS™ also
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provides message handling functions that support two-way communications between
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programs and system users, between programs, between procedures within a program,
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and between system users. Two types of messages are supported: </p>
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<ul><li>Immediate messages, which are created by the program or system user when
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they are sent and are not permanently stored in the system.</li>
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<li>Predefined messages, which are created before they are used. These messages
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are placed in a message file when they are created, and retrieved from that
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file when they are used.</li>
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</ul>
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<p>Because messages can be used to provide communications between programs,
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between procedures in a program, and between programs and users, using the i5/OS message
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handling functions should be considered when developing applications. The
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following concepts of message handling are important to application development:
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</p>
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<ul><li>Messages can be defined in messages files, which are outside the programs
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that use them, and variable information can be provided in the message text
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when a message is sent. Because messages are defined outside the programs,
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the programs do not have to be changed when the messages are changed. This
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approach also allows the same program to be used with message files containing
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translations of the messages into different languages.</li>
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<li>Messages are sent to and received from message queues, which are separate
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objects on the system. A message sent to a queue can remain on the queue
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until it is explicitly received by a program or workstation user.</li>
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<li>A program can send messages to a user who requested the program regardless
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of what workstation that user has signed on to. Messages do not have to be
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sent to a specific device; one program can be used from different workstations
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without change.</li>
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</ul>
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</div>
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<div>
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<ul class="ullinks">
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<li class="ulchildlink"><strong><a href="intmsgd.htm">Message descriptions</a></strong><br />
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A message description defines a message to i5/OS.</li>
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<li class="ulchildlink"><strong><a href="intmsgq.htm">Message queues</a></strong><br />
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When a message is sent to a procedure, a program, or a system user, it is placed on a message queue associated with that procedure, program, or user. The procedure, program, or user sees the message by receiving it from the queue.</li>
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</ul>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="intro.htm" title="This describes how you can control the operation of the system using control language (CL), menu options, and system messages.">System operation control</a></div>
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</div>
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<div class="reltasks"><strong>Related tasks</strong><br />
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<div><a href="wmsgs.htm" title="This discusses some of the ways that messages can be used to communicate between users and programs.">Messages</a></div>
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</div>
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<div class="relinfo"><strong>Related information</strong><br />
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<div><a href="../nls/rbagsglobalmain.htm">Globalization</a></div>
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</div>
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</div>
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</body>
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</html>
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