202 lines
6.0 KiB
HTML
202 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>pthread_mutex_destroy()--Destroy Mutex</title>
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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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<!-- Begin Header Records ========================================== -->
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<!-- NETMG2 SCRIPT A converted by B2H R4.1 (346) (CMS) by HOLTJM at -->
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<!-- RCHVMW2 on 29 Jan 1999 at 10:01:37 -->
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<!--File Edited November 2001 -->
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<!--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 language="Javascript" src="../rzahg/synch.js" type="text/javascript">
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</script>
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<a name="Top_Of_Page"></a>
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<h2>pthread_mutex_destroy()--Destroy Mutex</h2>
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<div class="box" style="width: 60%;">
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<br>
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Syntax:
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<pre>
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#include <pthread.h>
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int pthread_mutex_destroy(pthread_mutex_t *mutex);
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</pre>
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Service Program Name: QP0WPTHR<br>
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<!-- iddvc RMBR -->
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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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Threadsafe: Yes<br>
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<!-- iddvc RMBR -->
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<br>
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Signal Safe: Yes<br>
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<!-- iddvc RMBR -->
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<br>
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</div>
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<p>The <strong>pthread_mutex_destroy</strong>() function destroys the named
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mutex. The destroyed mutex can no longer be used.</p>
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<p>If <strong>pthread_mutex_destroy</strong>() is called on a mutex that is
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locked by another thread, the request fails with an <strong>EBUSY</strong>
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error. If the calling thread has the mutex locked, any other threads waiting
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for the mutex using a call to <strong>pthread_mutex_lock</strong>() at the time
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of the call to <strong>pthread_mutex_destroy</strong>() fails with the <strong>
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EDESTROYED</strong> error.</p>
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<p>Mutex initialization using the <strong>PTHREAD_MUTEX_INITIALIZER</strong>
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does not immediately initialize the mutex. Instead, on first use, <strong>
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pthread_mutex_lock</strong>() or <strong>pthread_mutex_trylock</strong>()
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branches into a slow path and causes the initialization of the mutex. Because a
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mutex is not just a simple memory object and requires that some resources be
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allocated by the system, an attempt to call <strong>
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pthread_mutex_destroy</strong>() or <strong>pthread_mutex_unlock</strong>() on
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a mutex that has statically initialized using <strong>
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PTHREAD_MUTEX_INITIALER</strong> and was not yet locked causes an <strong>
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EINVAL</strong> error.</p>
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<p>Every mutex must eventually be destroyed with <strong>
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pthread_mutex_destroy</strong>(). The machine eventually detects the error if a
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mutex is not destroyed, but the storage is deallocated or corrupted. The
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machine then creates LIC log synchronization entries that indicate the failure
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to help debug the problem. Large numbers of these entries can affect system
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performance and hinder debug capabilities for other system problems. Always use
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<strong>pthread_mutex_destroy</strong>() before freeing mutex storage to
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prevent these debug LIC log entries.</p>
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<p><strong>Note:</strong> Once a mutex is created, it cannot be validly copied
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or moved to a new location.</p>
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<br>
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<h3>Authorities and Locks</h3>
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<p>None.</p>
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<br>
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<h3>Parameters</h3>
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<dl>
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<dt><strong>mutex</strong></dt>
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<dd>(Input) Address of the mutex to be destroyed</dd>
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</dl>
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<br>
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<h3>Return Value</h3>
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<dl>
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<dt><strong>0</strong></dt>
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<dd><strong>pthread_mutex_destroy</strong>() was successful.</dd>
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<dt><strong>value</strong></dt>
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<dd><strong>pthread_mutex_destroy</strong>() was not successful. <em>value</em>
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is set to indicate the error condition.</dd>
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</dl>
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<br>
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<h3>Error Conditions</h3>
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<p>If <strong>pthread_mutex_destroy</strong>() was not successful, the error
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condition returned usually indicates one of the following errors. Under some
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conditions, the value returned could indicate an error other than those listed
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here.</p>
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<dl>
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<dt><em>[EBUSY]</em></dt>
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<dd><p>The mutex is currently owned by another thread.</p></dd>
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<dt><em>[EINVAL]</em></dt>
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<dd><p>The value specified for the argument is not correct.</p></dd>
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</dl>
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<br>
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<h3>Related Information</h3>
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<ul>
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<li>The <<strong>pthread.h</strong>> header file. See <a href=
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"rzah4hed.htm">Header files for Pthread functions</a>.<br><br></li>
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<li><a href="users_61.htm">pthread_mutex_init()</a>--Initialize Mutex<br><br></li>
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<li><a href="users_62.htm">pthread_mutex_lock()</a>--Lock Mutex<br><br></li>
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<li><a href="users_64.htm">pthread_mutex_trylock()</a>--Lock Mutex with No
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Wait<br><br></li>
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<li><a href="users_65.htm">pthread_mutex_unlock()</a>--Unlock Mutex</li>
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</ul>
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<br>
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<h3>Example</h3>
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<p>See <a href="../apiref/aboutapis.htm#codedisclaimer">Code disclaimer information</a>
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for information pertaining to code examples.</p>
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<pre>
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#include <pthread.h>
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#include <stdio.h>
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#include "check.h"
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pthread_mutex_t mutex;
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int main(int argc, char **argv)
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{
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int rc=0;
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pthread_mutexattr_t mta;
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printf("Entering testcase\n");
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printf("Create the mutex using the NULL attributes (default)\n");
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rc = pthread_mutex_init(&mutex, NULL);
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checkResults("pthread_mutex_init(NULL)\n", rc);
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printf("Destroy all mutexes\n");
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pthread_mutex_destroy(&mutex);
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checkResults("pthread_mutex_destroy()\n", rc);
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printf("Main completed\n");
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return 0;
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}
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</pre>
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<p><strong>Output:</strong></p>
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<pre>
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Entering testcase
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Create the mutex using the NULL attributes (default)
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Destroy all mutexes
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Main completed
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</pre>
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<hr>
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API introduced: V4R3
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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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"rzah4mst.htm">Pthread APIs</a> | <a href="aplist.htm">APIs by
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category</a></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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