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<title>pthread_setconcurrency()--Set Process Concurrency Level</title>
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<h2>pthread_setconcurrency()--Set Process Concurrency Level</h2>
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<br>
&nbsp;&nbsp;Syntax:
<pre>
#include &lt;pthread.h&gt;
int pthread_setconcurrency(int concurrency);
</pre>
&nbsp;&nbsp;Service Program Name: QP0WTCBH<br>
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&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_setconcurrency</strong>() function sets the current
concurrency level for the process.</p>
<p>A concurrency value of zero indicates that the threads implementation
chooses the concurrency level that best suits the application. A concurrency
level greater than zero indicates that the application wants to inform the
system of its desired concurrency level.</p>
<p>The concurrency level is not used by the i5/OS threads implementation, but
is stored for subsequent calls to <strong>pthread_getconcurrency()</strong>.
Each user thread is always bound to a kernel thread.</p>
<br>
<h3>Authorities and Locks</h3>
<p>None.</p>
<br>
<h3>Parameters</h3>
<dl>
<dt><strong>concurrency</strong></dt>
<dd>(Input) The new concurrency level for the process</dd>
</dl>
<br>
<h3>Return Value</h3>
<dl>
<dt><strong>0</strong></dt>
<dd><strong>pthread_setconcurrency</strong>() was successful.<br><br></dd>
<dt><strong>value</strong></dt>
<dd><strong>pthread_setconcurrency</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_setconcurrency</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>
<dl>
<dt><em>[EINVAL]</em></dt>
<dd><p>The value specified for the argument is not correct.</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="users19b.htm">pthread_getconcurrency()</a>--Get Process Concurrency
Level</li>
</ul>
<br>
<hr>API introduced: V4R3
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