69 lines
4.3 KiB
HTML
69 lines
4.3 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="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="Program storage" />
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<meta name="abstract" content="Two steps are needed to run a program: program activation and program invocation." />
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<meta name="description" content="Two steps are needed to run a program: program activation and program invocation." />
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<meta name="DC.Relation" scheme="URI" content="MIpgmg.htm" />
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<meta name="DC.Relation" scheme="URI" content="MIenhver.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="MIprosto" />
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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>Program storage</title>
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</head>
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<body id="MIprosto"><a name="MIprosto"><!-- --></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">Program storage</h1>
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<div><p>Two steps are needed to run a program: program activation and program
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invocation.</p>
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<p><span class="uicontrol">Program activation</span> is the process of allocating
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and initializing static storage for the program. <span class="uicontrol">Program invocation</span> is
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the process of allocating and initializing automatic storage.</p>
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<div class="section"><h4 class="sectiontitle">Program activation and static storage</h4><p>Program activation
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can be done explicitly through the Activate Program (ACTPG) instruction or
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implicitly by using a call external (CALLX) instruction when the called program
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has not been previously activated. Program activation typically occurs only
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once within a job or process. Program activation is not reset by an RTX instruction
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within the called program (the program is still considered to be in an activated
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state). This means that all static storage on subsequent calls (CALLXs) to
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the program are found in a last-used state, not in a reinitialized state.
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If a programmer wants to reinitialize the static storage associated with a
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program activation, this can be accomplished through the deactivate program
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(DEACTPG) instruction so that the next call (CALLX or ACTPG) causes a new
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activation of the program.</p>
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</div>
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<div class="section"><h4 class="sectiontitle">Program invocation and automatic storage</h4><p>Program
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invocation, on the other hand, occurs every time a program is called with
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a CALLX instruction. Automatic storage is reinitialized if a discrete INIT
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value was specified on the declare (DCL) statement. (If the INIT was allowed
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to be the default, then whether or not initialization occurs for the field
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is determined by an option of the QPRCRTPG API when the program was created.)
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If you have not already done so, review all of the option template values
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available on the QPRCRTPG API before developing your MI applications.</p>
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</div>
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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="MIpgmg.htm" title="Provides information about creating machine interface (MI) programs.">Machine interface programming</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="MIenhver.htm" title="A new version of MICRTPG (named MICRTPG2) incorporateS the functions of the CL03 program and the CL05 program.">Enhanced version of the MICRTPG program</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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