173 lines
6.8 KiB
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173 lines
6.8 KiB
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<title>pthread_spin_destroy</title>
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<basefont size="3"> <a name="pthread_spin_destroy"></a> <a name="tag_03_574"></a><!-- pthread_spin_destroy -->
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<!--header start-->
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<center><font size="2">The Open Group Base Specifications Issue 6<br>
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IEEE Std 1003.1-2001<br>
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Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
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<!--header end-->
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<hr size="2" noshade>
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<h4><a name="tag_03_574_01"></a>NAME</h4>
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<blockquote>pthread_spin_destroy, pthread_spin_init - destroy or initialize a spin lock object (<b>ADVANCED REALTIME
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THREADS</b>)</blockquote>
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<h4><a name="tag_03_574_02"></a>SYNOPSIS</h4>
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<blockquote class="synopsis">
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<div class="box"><code><tt><sup>[<a href="javascript:open_code('THR SPI')">THR SPI</a>]</sup> <img src="../images/opt-start.gif" alt=
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"[Option Start]" border="0"> #include <<a href="../basedefs/pthread.h.html">pthread.h</a>><br>
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<br>
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int pthread_spin_destroy(pthread_spinlock_t *</tt><i>lock</i><tt>);<br>
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int pthread_spin_init(pthread_spinlock_t *</tt><i>lock</i><tt>, int</tt> <i>pshared</i><tt>); <img src="../images/opt-end.gif"
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alt="[Option End]" border="0"></tt></code></div>
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<tt><br>
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</tt></blockquote>
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<h4><a name="tag_03_574_03"></a>DESCRIPTION</h4>
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<blockquote>
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<p>The <i>pthread_spin_destroy</i>() function shall destroy the spin lock referenced by <i>lock</i> and release any resources used
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by the lock. The effect of subsequent use of the lock is undefined until the lock is reinitialized by another call to
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<i>pthread_spin_init</i>(). The results are undefined if <i>pthread_spin_destroy</i>() is called when a thread holds the lock, or
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if this function is called with an uninitialized thread spin lock.</p>
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<p>The <i>pthread_spin_init</i>() function shall allocate any resources required to use the spin lock referenced by <i>lock</i> and
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initialize the lock to an unlocked state.</p>
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<p><sup>[<a href="javascript:open_code('TSH')">TSH</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
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If the Thread Process-Shared Synchronization option is supported and the value of <i>pshared</i> is PTHREAD_PROCESS_SHARED, the
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implementation shall permit the spin lock to be operated upon by any thread that has access to the memory where the spin lock is
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allocated, even if it is allocated in memory that is shared by multiple processes.</p>
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<p>If the Thread Process-Shared Synchronization option is supported and the value of <i>pshared</i> is PTHREAD_PROCESS_PRIVATE,
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<img src="../images/opt-end.gif" alt="[Option End]" border="0"> or if the option is not supported, the spin lock shall only be
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operated upon by threads created within the same process as the thread that initialized the spin lock. If threads of differing
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processes attempt to operate on such a spin lock, the behavior is undefined.</p>
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<p>The results are undefined if <i>pthread_spin_init</i>() is called specifying an already initialized spin lock. The results are
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undefined if a spin lock is used without first being initialized.</p>
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<p>If the <i>pthread_spin_init</i>() function fails, the lock is not initialized and the contents of <i>lock</i> are undefined.</p>
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<p>Only the object referenced by <i>lock</i> may be used for performing synchronization.</p>
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<p>The result of referring to copies of that object in calls to <i>pthread_spin_destroy</i>(), <a href=
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"../functions/pthread_spin_lock.html"><i>pthread_spin_lock</i>()</a>, <a href=
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"../functions/pthread_spin_trylock.html"><i>pthread_spin_trylock</i>()</a>, or <a href=
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"../functions/pthread_spin_unlock.html"><i>pthread_spin_unlock</i>()</a> is undefined.</p>
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</blockquote>
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<h4><a name="tag_03_574_04"></a>RETURN VALUE</h4>
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<blockquote>
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<p>Upon successful completion, these functions shall return zero; otherwise, an error number shall be returned to indicate the
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error.</p>
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</blockquote>
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<h4><a name="tag_03_574_05"></a>ERRORS</h4>
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<blockquote>
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<p>These functions may fail if:</p>
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<dl compact>
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<dt>[EBUSY]</dt>
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<dd>The implementation has detected an attempt to initialize or destroy a spin lock while it is in use (for example, while being
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used in a <a href="../functions/pthread_spin_lock.html"><i>pthread_spin_lock</i>()</a> call) by another thread.</dd>
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<dt>[EINVAL]</dt>
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<dd>The value specified by <i>lock</i> is invalid.</dd>
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</dl>
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<p>The <i>pthread_spin_init</i>() function shall fail if:</p>
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<dl compact>
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<dt>[EAGAIN]</dt>
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<dd>The system lacks the necessary resources to initialize another spin lock.</dd>
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<dt>[ENOMEM]</dt>
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<dd>Insufficient memory exists to initialize the lock.</dd>
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</dl>
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<p>These functions shall not return an error code of [EINTR].</p>
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</blockquote>
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<hr>
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<div class="box"><em>The following sections are informative.</em></div>
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<h4><a name="tag_03_574_06"></a>EXAMPLES</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_574_07"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>The <i>pthread_spin_destroy</i>() and <i>pthread_spin_init</i>() functions are part of the Spin Locks option and need not be
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provided on all implementations.</p>
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</blockquote>
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<h4><a name="tag_03_574_08"></a>RATIONALE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_574_09"></a>FUTURE DIRECTIONS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_574_10"></a>SEE ALSO</h4>
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<blockquote>
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<p><a href="pthread_spin_lock.html"><i>pthread_spin_lock</i>()</a> , <a href=
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"pthread_spin_unlock.html"><i>pthread_spin_unlock</i>()</a> , the Base Definitions volume of IEEE Std 1003.1-2001, <a
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href="../basedefs/pthread.h.html"><i><pthread.h></i></a></p>
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</blockquote>
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<h4><a name="tag_03_574_11"></a>CHANGE HISTORY</h4>
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<blockquote>
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<p>First released in Issue 6. Derived from IEEE Std 1003.1j-2000.</p>
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<p>In the SYNOPSIS, the inclusion of <a href="../basedefs/sys/types.h.html"><i><sys/types.h></i></a> is no longer
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required.</p>
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</blockquote>
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<div class="box"><em>End of informative text.</em></div>
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