208 lines
6.0 KiB
HTML
208 lines
6.0 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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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="Copyright" content="Copyright (c) 2006 by IBM Corporation">
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<title>fork400()--Create a New Process With i5/OS PASE Options</title>
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<!-- Begin Header Records -->
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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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<!-- Change History: -->
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<!-- YYMMDD USERID Change description -->
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<!-- Created by wrmadden on 04 Apr 2003 --><!--End Header Records -->
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<link rel="stylesheet" type="text/css" href="../rzahg/ic.css">
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</head>
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<body>
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<!-- Java sync-link -->
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<script type="text/javascript" language="Javascript" src="../rzahg/synch.js">
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</script>
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<a name="Top_Of_Page"></a>
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<h2>fork400()and f_fork400()--Create A New Process with i5/OS PASE Options</h2>
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<div class="box" style="width: 70%;">
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<br>
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<br>
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Syntax
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<pre>
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#include <as400_protos.h>
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pid_t fork400(const char *<em>jobname</em>,
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unsigned int <em>resourceID</em>);
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pid_t f_fork400(const char *<em>jobname</em>,
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unsigned int <em>resourceID</em>);
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</pre>
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<br>
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Default Public Authority: *USE<br>
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<!-- iddvc RMBR -->
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<br>
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Library: Standard C Library (libc.a)<br>
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<!-- iddvc RMBR -->
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<br>
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Threadsafe: Yes<br>
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<!-- iddvc RMBR -->
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<br>
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</div>
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<br>
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<p><strong>Note:</strong> These functions can only be used in an i5/OS PASE
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program. See <a href="../rzalf/rzalfintro.htm">i5/OS PASE</a> for more
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information about creating i5/OS PASE programs.</p>
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<p>The <strong>fork400()</strong> function creates a new process.
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The new process (the child process) is an almost exact copy of the
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calling process (the parent process).
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<strong>fork400()</strong>
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is called once (by the parent process), but returns
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twice (once in the parent process and once in the child process).
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<strong>fork400()</strong> is the same as
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the <strong>fork()</strong> function plus it allows additional i5/OS
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PASE unique options to be specified.
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</p>
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<p><strong>f_fork400()</strong> function is a similarly enhanced
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version of the <strong>f_fork()</strong> function.
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When <strong>f_fork400()</strong> (or <strong>f_fork()</strong>)
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is used, one of the <strong>exec</strong> functions must be
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called in the child process immediately after
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it is created.
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<strong>f_fork400()</strong> does not call the fork handlers so
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the application data, mutexes and the locks are all undefined
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in the child process.
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</p>
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<br>
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<h3>Parameters</h3>
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<dl>
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<dt><strong>jobname</strong></dt>
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<dd>(Input)
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Pointer to a null-terminated string in the i5/OS PASE CCSID that specifies the
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i5/OS job name of the new process.
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<p>The job name specified must begin with an alphabetic character [A-Z] or the characters [$#@].
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The remaining characters must be alphanumeric [A-Z] or [0-9] or [$#@_.].
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The string should not be longer than 10 characters (not including the terminating null character).
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If the specified jobname is invalid, the jobname parameter value is ignored.
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</p>
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</dd>
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<dt><strong>resourceID</strong></dt>
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<dd>(Input)
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A positive integer value specifying the resources affinity identifier
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for the new process.
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<p>
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Use the value of 0 to
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let the operating system select the resources affinity identifier value automatically.
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</p>
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</dd>
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</dl>
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<br>
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<h3>Authorities</h3>
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<p><strong>fork400()</strong> and <strong>f_fork400()</strong> require no authority.</p>
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<br>
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<h3>Return Value</h3>
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<p>Upon successful completion, the <strong>fork400()</strong>
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or <strong>f_fork400()</strong> function returns a value of 0
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to the child process and the process ID of the child process
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to the parent process. Otherwise, a value of -1 is returned
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to the parent process, no child process is created,
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and the errno global variable is set to indicate the error.
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</p>
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<br>
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<h3>Error Conditions</h3>
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<p>At least these errno values can be returned, with other values also possible
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(such as i5/OS-unique ILE errno EAPAR):</p>
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<table cellpadding="5">
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<!-- cols="25 75" -->
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<tr>
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<td align="left" valign="top"><em>[EAGAIN]</em></td>
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<td align="left" valign="top">Exceeds the limit on the total number of processes
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running or the system does not have the resources necessary to create
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another process.
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[ENOMEM]</em></td>
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<td align="left" valign="top">Not enough space exists for this process.
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EINVAL]</em></td>
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<td align="left" valign="top">An invalid argument value was specified.
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</td>
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</tr>
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</table>
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<br>
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<br>
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<h3>Usage Notes</h3>
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<ol>
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<li>Consult the AIX documentation for <strong>fork()</strong>
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and <strong>f_fork()</strong> for additional details regarding
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attributes of the parent process inherited by the
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child process and differences between <strong>fork()</strong> and <strong>f_fork()</strong>.
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<br>
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</li>
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<li>The i5/OS PASE environment specification <em>QIBM_PASE_USE_PRESTART_JOBS=Y</em>
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will be ignored when the fork400() or f_fork400() functions are used with a non-null jobname
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or a non-zero resourceID value.
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</li>
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</ol>
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<br>
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<h3>Related Information</h3>
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<ul>
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<li>See the <a href="pase_environ.htm">i5/OS PASE Environment Variables</a>
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documentation for information about the <em>PASE_FORK_JOBNAME</em>
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environment variable that can be used to specify the
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i5/OS job name for new processes created using
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the <strong>fork()</strong> or <strong>f_fork()</strong> functions.
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</li>
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</ul>
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<br>
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<p></p>
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<hr>
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API introduced: V5R3
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<hr>
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<center>
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<table cellpadding="2" cellspacing="2">
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<tr align="center">
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<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> | <a href=
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"pase1.htm">i5/OS PASE APIs</a> | <a href="aplist.htm">APIs by category</a>
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</td>
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</tr>
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</table>
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</center>
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</body>
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</html>
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