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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_rwlockattr_getpshared</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="pthread_rwlockattr_getpshared"></a> <a name="tag_03_564"></a><!-- pthread_rwlockattr_getpshared --> <!--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_564_01"></a>NAME</h4><blockquote>pthread_rwlockattr_getpshared, pthread_rwlockattr_setpshared - get and set the process-shared attribute of theread-write lock attributes object</blockquote><h4><a name="tag_03_564_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 <<a href="../basedefs/pthread.h.html">pthread.h</a>><br><br> int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *<br> restrict</tt> <i>attr</i><tt>, int *restrict</tt> <i>pshared</i><tt>);<br> int pthread_rwlockattr_setpshared(pthread_rwlockattr_t</tt> <i>*attr</i><tt>,<br> 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_564_03"></a>DESCRIPTION</h4><blockquote><p>The <i>pthread_rwlockattr_getpshared</i>() function shall obtain the value of the <i>process-shared</i> attribute from theinitialized attributes object referenced by <i>attr</i>. The <i>pthread_rwlockattr_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 shall be set to PTHREAD_PROCESS_SHARED to permit a read-write lock to be operated upon byany thread that has access to the memory where the read-write lock is allocated, even if the read-write lock is allocated in memorythat is shared by multiple processes. If the <i>process-shared</i> attribute is PTHREAD_PROCESS_PRIVATE, the read-write lock shallonly be operated upon by threads created within the same process as the thread that initialized the read-write lock; if threads ofdiffering processes attempt to operate on such a read-write lock, the behavior is undefined. The default value of the<i>process-shared</i> attribute shall be PTHREAD_PROCESS_PRIVATE.</p><p>Additional attributes, their default values, and the names of the associated functions to get and set those attribute values areimplementation-defined.</p></blockquote><h4><a name="tag_03_564_04"></a>RETURN VALUE</h4><blockquote><p>Upon successful completion, the <i>pthread_rwlockattr_getpshared</i>() function 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 errornumber shall be returned to indicate the error.</p><p>If successful, the <i>pthread_rwlockattr_setpshared</i>() function shall return zero; otherwise, an error number shall bereturned to indicate the error.</p></blockquote><h4><a name="tag_03_564_05"></a>ERRORS</h4><blockquote><p>The <i>pthread_rwlockattr_getpshared</i>() and <i>pthread_rwlockattr_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_rwlockattr_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_564_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_564_07"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_564_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_564_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_564_10"></a>SEE ALSO</h4><blockquote><p><a href="pthread_rwlock_destroy.html"><i>pthread_rwlock_destroy</i>()</a>, <a href="pthread_rwlockattr_destroy.html"><i>pthread_rwlockattr_destroy</i>()</a>, <a href="pthread_rwlockattr_init.html"><i>pthread_rwlockattr_init</i>()</a>, the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/pthread.h.html"><i><pthread.h></i></a></p></blockquote><h4><a name="tag_03_564_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 5.</p></blockquote><h4><a name="tag_03_564_12"></a>Issue 6</h4><blockquote><p>The following changes are made for alignment with IEEE Std 1003.1j-2000:</p><ul><li><p>The margin code in the SYNOPSIS is changed to THR TSH to indicate that the functionality is now part of the Threads option(previously it was part of the Read-Write Locks option in IEEE Std 1003.1j-2000 and also part of the XSI extension).</p></li><li><p>The DESCRIPTION notes that additional attributes are implementation-defined.</p></li><li><p>The SEE ALSO section is updated.</p></li></ul><p>The <b>restrict</b> keyword is added to the <i>pthread_rwlockattr_getpshared</i>() prototype for alignment with theISO/IEC 9899:1999 standard.</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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