60 lines
3.7 KiB
HTML
60 lines
3.7 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 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="Processing lists that contain data structures" />
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<meta name="abstract" content="Some API information contains a list where each entry in the list is itself a data structure." />
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<meta name="description" content="Some API information contains a list where each entry in the list is itself a data structure." />
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<meta name="DC.Relation" scheme="URI" content="cmnCommon.htm" />
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<meta name="DC.Relation" scheme="URI" content="../apis/qwcrssts.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="cmnProcessList" />
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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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<!-- 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> Processing lists that contain data structures</title>
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</head>
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<body id="cmnProcessList"><a name="cmnProcessList"><!-- --></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"> Processing lists that contain data structures</h1>
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<div><p>Some API information contains a list where each entry in the list
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is itself a data structure.</p>
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<p>A good example is the Retrieve System Status (QWCRSSTS) API.
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It supports multiple formats for different types of information. The SSTS0300
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format contains a list where each entry in the list has the information about
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a particular storage pool. In addition to the two critical fields (the offset
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to where the list begins field and the number of entries in the list field),
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the format also supports a field that describes the length of each entry.
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In the initial library list, each entry was 11-bytes long. But in a storage
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pool, a field (length of pool information entry) describes the length and
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should be used instead of a fixed-length increment. This allows for growth,
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such as more information being available in another release for each list
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entry.</p>
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<p>For example, if another field is added to describe some additional information
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about a storage pool, it is probably added after the paging option field.
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The length of pool information entry allows your code to be upwardly compatible
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while it retains the locations (relative to the start of a list entry) of
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the current fields.</p>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="cmnCommon.htm" title="API names contain verbs that are similar to the i5/OS licensed program: change, create, remove, and retrieve.">API information format</a></div>
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</div>
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<div class="relref"><strong>Related reference</strong><br />
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<div><a href="../apis/qwcrssts.htm">Retrieve System Status (QWCRSSTS) API</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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