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<title>pthread_rwlockattr_init()--Initialize Read/Write Lock Attribute</title>
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<h2>pthread_rwlockattr_init()--Initialize Read/Write Lock Attribute</h2>
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&nbsp;&nbsp;Syntax:
<pre> #include &lt;pthread.h&gt;
int pthread_rwlockattr_init(pthread_rwlockattr_t *attr); </pre>
&nbsp;&nbsp;Service Program Name: QP0WPTHR<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: Yes<br>
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<p>The <strong>pthread_rwlockattr_init</strong>() function initializes the read/write lock attributes
object referred to by <em>attr</em> to the default attributes. The read/write lock attributes object
can be used in a call to <strong>pthread_rwlock_init</strong>() to create a read/write lock.</p>
<br>
<h3>Authorities and Locks</h3>
<p>None.</p>
<br>
<h3>
Parameters</h3>
<dl>
<dt><strong>attr</strong></dt>
<dd>(Output) Address of the variable to contain the read/write lock attributes object</dd>
</dl>
<br>
<h3>Return Value</h3>
<dl>
<dt><strong>0</strong></dt>
<dd><strong>pthread_rwlockattr_init</strong>() was successful.</dd>
<dt><strong>value</strong></dt>
<dd><strong>pthread_rwlockattr_init</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_rwlockattr_init</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>
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<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_81.htm">pthread_rwlockattr_destroy()</a>--Destroy Read/Write Lock Attribute<br><br></li>
<li><a href="users_86.htm">pthread_rwlock_init()</a>--Initialize Read/Write Lock</li>
</ul>
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<h3>Example</h3>
<p>See <a href="../apiref/aboutapis.htm#codedisclaimer">Code disclaimer information</a>
for information pertaining to code examples.</p>
<p>See the <a href="users_81.htm#371610"><strong>pthread_rwlockattr_destroy</strong>() example</a>.</p>
<hr>
API introduced: V4R3
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