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<title>pthread_mutexattr_getpshared</title>
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<basefont size="3"> <a name="pthread_mutexattr_getpshared"></a> <a name="tag_03_547"></a><!-- pthread_mutexattr_getpshared -->
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<center><font size="2">The Open Group Base Specifications Issue 6<br>
IEEE Std 1003.1-2001<br>
Copyright &copy; 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
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<hr size="2" noshade>
<h4><a name="tag_03_547_01"></a>NAME</h4>
<blockquote>pthread_mutexattr_getpshared, pthread_mutexattr_setpshared - get and set the process-shared attribute</blockquote>
<h4><a name="tag_03_547_02"></a>SYNOPSIS</h4>
<blockquote class="synopsis">
<div class="box"><code><tt><sup>[<a href="javascript:open_code('THR TSH')">THR TSH</a>]</sup> <img src="../images/opt-start.gif" alt=
"[Option Start]" border="0"> #include &lt;<a href="../basedefs/pthread.h.html">pthread.h</a>&gt;<br>
<br>
int pthread_mutexattr_getpshared(const pthread_mutexattr_t *<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; restrict</tt> <i>attr</i><tt>, int *restrict</tt> <i>pshared</i><tt>);<br>
int pthread_mutexattr_setpshared(pthread_mutexattr_t *</tt><i>attr</i><tt>,<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; int</tt> <i>pshared</i><tt>); <img src="../images/opt-end.gif" alt="[Option End]" border=
"0"></tt></code></div>
<tt><br>
</tt></blockquote>
<h4><a name="tag_03_547_03"></a>DESCRIPTION</h4>
<blockquote>
<p>The <i>pthread_mutexattr_getpshared</i>() function shall obtain the value of the <i>process-shared</i> attribute from the
attributes object referenced by <i>attr</i>. The <i>pthread_mutexattr_setpshared</i>() function shall set the <i>process-shared</i>
attribute in an initialized attributes object referenced by <i>attr</i>.</p>
<p>The <i>process-shared</i> attribute is set to PTHREAD_PROCESS_SHARED to permit a mutex to be operated upon by any thread that
has access to the memory where the mutex is allocated, even if the mutex is allocated in memory that is shared by multiple
processes. If the <i>process-shared</i> attribute is PTHREAD_PROCESS_PRIVATE, the mutex shall only be operated upon by threads
created within the same process as the thread that initialized the mutex; if threads of differing processes attempt to operate on
such a mutex, the behavior is undefined. The default value of the attribute shall be PTHREAD_PROCESS_PRIVATE.</p>
</blockquote>
<h4><a name="tag_03_547_04"></a>RETURN VALUE</h4>
<blockquote>
<p>Upon successful completion, <i>pthread_mutexattr_setpshared</i>() shall return zero; otherwise, an error number shall be
returned to indicate the error.</p>
<p>Upon successful completion, <i>pthread_mutexattr_getpshared</i>() shall return zero and store the value of the
<i>process-shared</i> attribute of <i>attr</i> into the object referenced by the <i>pshared</i> parameter. Otherwise, an error
number shall be returned to indicate the error.</p>
</blockquote>
<h4><a name="tag_03_547_05"></a>ERRORS</h4>
<blockquote>
<p>The <i>pthread_mutexattr_getpshared</i>() and <i>pthread_mutexattr_setpshared</i>() functions may fail if:</p>
<dl compact>
<dt>[EINVAL]</dt>
<dd>The value specified by <i>attr</i> is invalid.</dd>
</dl>
<p>The <i>pthread_mutexattr_setpshared</i>() function may fail if:</p>
<dl compact>
<dt>[EINVAL]</dt>
<dd>The new value specified for the attribute is outside the range of legal values for that attribute.</dd>
</dl>
<p>These functions shall not return an error code of [EINTR].</p>
</blockquote>
<hr>
<div class="box"><em>The following sections are informative.</em></div>
<h4><a name="tag_03_547_06"></a>EXAMPLES</h4>
<blockquote>
<p>None.</p>
</blockquote>
<h4><a name="tag_03_547_07"></a>APPLICATION USAGE</h4>
<blockquote>
<p>None.</p>
</blockquote>
<h4><a name="tag_03_547_08"></a>RATIONALE</h4>
<blockquote>
<p>None.</p>
</blockquote>
<h4><a name="tag_03_547_09"></a>FUTURE DIRECTIONS</h4>
<blockquote>
<p>None.</p>
</blockquote>
<h4><a name="tag_03_547_10"></a>SEE ALSO</h4>
<blockquote>
<p><a href="pthread_cond_destroy.html"><i>pthread_cond_destroy</i>()</a> , <a href=
"pthread_create.html"><i>pthread_create</i>()</a> , <a href="pthread_mutex_destroy.html"><i>pthread_mutex_destroy</i>()</a> , <a
href="pthread_mutexattr_destroy.html"><i>pthread_mutexattr_destroy</i>()</a> , the Base Definitions volume of
IEEE&nbsp;Std&nbsp;1003.1-2001, <a href="../basedefs/pthread.h.html"><i>&lt;pthread.h&gt;</i></a></p>
</blockquote>
<h4><a name="tag_03_547_11"></a>CHANGE HISTORY</h4>
<blockquote>
<p>First released in Issue 5. Included for alignment with the POSIX Threads Extension.</p>
</blockquote>
<h4><a name="tag_03_547_12"></a>Issue 6</h4>
<blockquote>
<p>The <i>pthread_mutexattr_getpshared</i>() and <i>pthread_mutexattr_setpshared</i>() functions are marked as part of the Threads
and Thread Process-Shared Synchronization options.</p>
<p>The <b>restrict</b> keyword is added to the <i>pthread_mutexattr_getpshared</i>() prototype for alignment with the
ISO/IEC&nbsp;9899:1999 standard.</p>
</blockquote>
<div class="box"><em>End of informative text.</em></div>
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