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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2004 IEEE and The Open Group, All Rights Reserved --><title>pthread_spin_destroy</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="pthread_spin_destroy"></a> <a name="tag_03_574"></a><!-- pthread_spin_destroy --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2004 Edition<br>Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_03_574_01"></a>NAME</h4><blockquote>pthread_spin_destroy, pthread_spin_init - destroy or initialize a spin lock object (<b>ADVANCED REALTIMETHREADS</b>)</blockquote><h4><a name="tag_03_574_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><div class="box"><code><tt><sup>[<a href="javascript:open_code('THR SPI')">THR SPI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> #include <<a href="../basedefs/pthread.h.html">pthread.h</a>><br><br> int pthread_spin_destroy(pthread_spinlock_t *</tt><i>lock</i><tt>);<br> int pthread_spin_init(pthread_spinlock_t *</tt><i>lock</i><tt>, 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_574_03"></a>DESCRIPTION</h4><blockquote><p>The <i>pthread_spin_destroy</i>() function shall destroy the spin lock referenced by <i>lock</i> and release any resources usedby the lock. The effect of subsequent use of the lock is undefined until the lock is reinitialized by another call to<i>pthread_spin_init</i>(). The results are undefined if <i>pthread_spin_destroy</i>() is called when a thread holds the lock, orif this function is called with an uninitialized thread spin lock.</p><p>The <i>pthread_spin_init</i>() function shall allocate any resources required to use the spin lock referenced by <i>lock</i> andinitialize the lock to an unlocked state.</p><p><sup>[<a href="javascript:open_code('TSH')">TSH</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">If the Thread Process-Shared Synchronization option is supported and the value of <i>pshared</i> is PTHREAD_PROCESS_SHARED, theimplementation shall permit the spin lock to be operated upon by any thread that has access to the memory where the spin lock isallocated, even if it is allocated in memory that is shared by multiple processes.</p><p>If the Thread Process-Shared Synchronization option is supported and the value of <i>pshared</i> is PTHREAD_PROCESS_PRIVATE,<img src="../images/opt-end.gif" alt="[Option End]" border="0"> or if the option is not supported, the spin lock shall only beoperated upon by threads created within the same process as the thread that initialized the spin lock. If threads of differingprocesses attempt to operate on such a spin lock, the behavior is undefined.</p><p>The results are undefined if <i>pthread_spin_init</i>() is called specifying an already initialized spin lock. The results areundefined if a spin lock is used without first being initialized.</p><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><p>Only the object referenced by <i>lock</i> may be used for performing synchronization.</p><p>The result of referring to copies of that object in calls to <i>pthread_spin_destroy</i>(), <a href="../functions/pthread_spin_lock.html"><i>pthread_spin_lock</i>()</a>, <a href="../functions/pthread_spin_trylock.html"><i>pthread_spin_trylock</i>()</a>, or <a href="../functions/pthread_spin_unlock.html"><i>pthread_spin_unlock</i>()</a> is undefined.</p></blockquote><h4><a name="tag_03_574_04"></a>RETURN VALUE</h4><blockquote><p>Upon successful completion, these functions shall return zero; otherwise, an error number shall be returned to indicate theerror.</p></blockquote><h4><a name="tag_03_574_05"></a>ERRORS</h4><blockquote><p>These functions may fail if:</p><dl compact><dt>[EBUSY]</dt><dd>The implementation has detected an attempt to initialize or destroy a spin lock while it is in use (for example, while beingused in a <a href="../functions/pthread_spin_lock.html"><i>pthread_spin_lock</i>()</a> call) by another thread.</dd><dt>[EINVAL]</dt><dd>The value specified by <i>lock</i> is invalid.</dd></dl><p>The <i>pthread_spin_init</i>() function shall fail if:</p><dl compact><dt>[EAGAIN]</dt><dd>The system lacks the necessary resources to initialize another spin lock.</dd><dt>[ENOMEM]</dt><dd>Insufficient memory exists to initialize the lock.</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_574_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_574_07"></a>APPLICATION USAGE</h4><blockquote><p>The <i>pthread_spin_destroy</i>() and <i>pthread_spin_init</i>() functions are part of the Spin Locks option and need not beprovided on all implementations.</p></blockquote><h4><a name="tag_03_574_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_574_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_574_10"></a>SEE ALSO</h4><blockquote><p><a href="pthread_spin_lock.html"><i>pthread_spin_lock</i>()</a>, <a href="pthread_spin_unlock.html"><i>pthread_spin_unlock</i>()</a>, the Base Definitions volume of IEEE Std 1003.1-2001, <ahref="../basedefs/pthread.h.html"><i><pthread.h></i></a></p></blockquote><h4><a name="tag_03_574_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 6. Derived from IEEE Std 1003.1j-2000.</p><p>In the SYNOPSIS, the inclusion of <a href="../basedefs/sys/types.h.html"><i><sys/types.h></i></a> is no longerrequired.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr size="2" noshade><center><font size="2"><!--footer start-->UNIX ® is a registered Trademark of The Open Group.<br>POSIX ® is a registered Trademark of The IEEE.<br>[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href="../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>]</font></center><!--footer end--><hr size="2" noshade></body></html>⌨️ 快捷键说明
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