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<title>pthread_key_delete()--Delete Thread Local Storage Key</title>
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<h2>pthread_key_delete()--Delete Thread Local Storage Key</h2>
<div class="box" style="width: 50%;">
<br>
&nbsp;&nbsp;Syntax:
<pre>
#include &lt;pthread.h&gt;
int pthread_key_delete(pthread_key_t key);
</pre>
&nbsp;&nbsp;Service Program Name: QP0WPTHR<br>
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<br>
&nbsp;&nbsp;Default Public Authority: *USE<br>
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&nbsp;&nbsp;Threadsafe: Yes<br>
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&nbsp;&nbsp;Signal Safe: No<br>
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<p>The <strong>pthread_key_delete</strong>() function deletes a process-wide
thread local storage <em>key</em>. The <strong>pthread_key_delete</strong>()
function does not run any destructors for the values associated with
<em>key</em> in any threads. After a key is deleted, it may be returned by a
subsequent call to <strong>pthread_key_create</strong>().</p>
<p>An attempt to delete a key that is out of range or not valid fails with
EINVAL. An attempt to delete a valid key that has already been deleted or has
not been returned from <strong>pthread_key_create</strong>() fails with
ENOENT.</p>
<br>
<h3>Authorities and Locks</h3>
<p>None.</p>
<br>
<h3>Parameters</h3>
<dl>
<dt><strong>key</strong></dt>
<dd>(Input) The thread local storage key returned from
<strong>pthread_key_create</strong>()</dd>
</dl>
<br>
<h3>Return Value</h3>
<dl>
<dt><strong>0</strong></dt>
<dd><strong>pthread_key_delete</strong>() was successful.<br><br></dd>
<dt><strong>value</strong></dt>
<dd><strong>pthread_key_delete(</strong>) was not successful. <em>value</em> is
set to indicate the error condition.</dd>
</dl>
<br>
<h3>Error Conditions</h3>
<p>If <strong>pthread_key_delete</strong>() was not successful, the error
condition returned usually indicates one of the following errors. Under some
conditions, the value returned could indicate an error other than those listed
here.</p>
<p>A destructor function is not called as a result of the application calling
<strong>pthread_key_delete</strong>().</p>
<dl>
<dt><em>[EINVAL]</em></dt>
<dd><p>The value specified for the argument is not correct.</p></dd>
<dt><em>[ENOENT]</em></dt>
<dd><p>An entry for the key is not currently allocated.</p></dd>
</dl>
<br>
<h3>Related Information</h3>
<ul>
<li>The &lt;<strong>pthread.h</strong>&gt; header file. See <a href=
"rzah4hed.htm">Header files for Pthread functions</a>.<br><br></li>
<li><a href="users_34.htm">pthread_getspecific()</a>--Get Thread Local Storage
Value by Key<br><br></li>
<li><a href="users_35.htm">pthread_key_create()</a>--Create Thread Local Storage
Key<br><br></li>
<li><a href="users_37.htm">pthread_setspecific()</a>--Set Thread Local Storage by
Key</li>
</ul>
<br>
<h3>Example</h3>
<p>See <a href="../apiref/aboutapis.htm#codedisclaimer">Code disclaimer information</a>
for information pertaining to code examples.</p>
<pre>
#define _MULTI_THREADED
#include &lt;pthread.h&gt;
#include &lt;stdio.h&gt;
#include "check.h"
pthread_key_t tlsKey = 0;
void globalDestructor(void *value)
{
printf("In global data destructor\n");
free(value);
pthread_setspecific(tlsKey, NULL);
}
int main(int argc, char **argv)
{
int rc=0;
int i=0;
printf("Enter Testcase - %s\n", argv[0]);
printf("Create a thread local storage key\n");
rc = pthread_key_create(&amp;tlsKey, globalDestructor);
checkResults("pthread_key_create()\n", rc);
/* The key can now be used from all threads */
printf("Delete a thread local storage key\n");
rc = pthread_key_delete(tlsKey);
checkResults("pthread_key_delete()\n", rc);
printf("- The key should not be used from any thread\n");
printf("- after destruction.\n");
/* The key and any remaining values are now gone. */
printf("Main completed\n");
return 0;
}
</pre>
<p><strong>Output:</strong></p>
<pre>
Enter Testcase - QP0WTEST/TPKEYD0
Create a thread local storage key
Delete a thread local storage key
- The key should not be used from any thread
- after destruction.
Main completed
</pre>
<br>
<hr>API introduced: V4R3
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