static/freebsd/man3/pthread_rwlock_init.3 3.html


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<table class="head">
  <tr>
    <td class="head-ltitle">PTHREAD_RWLOCK_INIT(3)</td>
    <td class="head-vol">Library Functions Manual</td>
    <td class="head-rtitle">PTHREAD_RWLOCK_INIT(3)</td>
  </tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">pthread_rwlock_init</code> &#x2014;
    <span class="Nd">initialize a read/write lock</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="LIBRARY"><a class="permalink" href="#LIBRARY">LIBRARY</a></h1>
<p class="Pp"><span class="Lb">POSIX Threads Library (libpthread,
    -lpthread)</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="In">#include
    &lt;<a class="In">pthread.h</a>&gt;</code></p>
<p class="Pp"><var class="Ft">int</var>
  <br/>
  <code class="Fn">pthread_rwlock_init</code>(<var class="Fa" style="white-space: nowrap;">pthread_rwlock_t
    *restrict lock</var>, <var class="Fa" style="white-space: nowrap;">const
    pthread_rwlockattr_t *restrict attr</var>);</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The
    <a class="permalink" href="#pthread_rwlock_init"><code class="Fn" id="pthread_rwlock_init">pthread_rwlock_init</code></a>()
    function is used to initialize a read/write lock, with attributes specified
    by <var class="Fa">attr</var>. If <var class="Fa">attr</var> is NULL, the
    default read/write lock attributes are used.</p>
<p class="Pp" id="pthread_rwlock_init~2">The results of calling
    <a class="permalink" href="#pthread_rwlock_init~2"><code class="Fn">pthread_rwlock_init</code></a>()
    with an already initialized lock are undefined.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="RETURN_VALUES"><a class="permalink" href="#RETURN_VALUES">RETURN
  VALUES</a></h1>
<p class="Pp">If successful, the <code class="Fn">pthread_rwlock_init</code>()
    function will return zero. Otherwise an error number will be returned to
    indicate the error.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="ERRORS"><a class="permalink" href="#ERRORS">ERRORS</a></h1>
<p class="Pp">The <code class="Fn">pthread_rwlock_init</code>() function will
    fail if:</p>
<dl class="Bl-tag">
  <dt id="EAGAIN">[<a class="permalink" href="#EAGAIN"><code class="Er">EAGAIN</code></a>]</dt>
  <dd>The system lacked the necessary resources (other than memory) to
      initialize the lock.</dd>
  <dt id="ENOMEM">[<a class="permalink" href="#ENOMEM"><code class="Er">ENOMEM</code></a>]</dt>
  <dd>Insufficient memory exists to initialize the lock.</dd>
  <dt id="EPERM">[<a class="permalink" href="#EPERM"><code class="Er">EPERM</code></a>]</dt>
  <dd>The caller does not have sufficient privilege to perform the
    operation.</dd>
</dl>
<p class="Pp">The <code class="Fn">pthread_rwlock_init</code>() function may
    fail if:</p>
<dl class="Bl-tag">
  <dt id="EBUSY">[<a class="permalink" href="#EBUSY"><code class="Er">EBUSY</code></a>]</dt>
  <dd>The system has detected an attempt to re-initialize the object referenced
      by <var class="Fa">lock</var>, a previously initialized but not yet
      destroyed read/write lock.</dd>
  <dt id="EINVAL">[<a class="permalink" href="#EINVAL"><code class="Er">EINVAL</code></a>]</dt>
  <dd>The value specified by <var class="Fa">attr</var> is invalid.</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
  ALSO</a></h1>
<p class="Pp"><a class="Xr">pthread_rwlock_destroy(3)</a>,
    <a class="Xr">pthread_rwlockattr_init(3)</a>,
    <a class="Xr">pthread_rwlockattr_setpshared(3)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="STANDARDS"><a class="permalink" href="#STANDARDS">STANDARDS</a></h1>
<p class="Pp">The <code class="Fn">pthread_rwlock_init</code>() function is
    expected to conform to <span class="St">Version&#x00A0;2 of the Single UNIX
    Specification (&#x201C;SUSv2&#x201D;)</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">The <code class="Fn">pthread_rwlock_init</code>() function first
    appeared in <span class="Ux">FreeBSD 3.0</span>.</p>
</section>
</div>
<table class="foot">
  <tr>
    <td class="foot-date">August 17, 2018</td>
    <td class="foot-os">FreeBSD 15.0</td>
  </tr>
</table>