229 lines
8.6 KiB
HTML
229 lines
8.6 KiB
HTML
<!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 The Open Group, All Rights Reserved -->
|
|
<title>pthread_rwlock_destroy</title>
|
|
</head>
|
|
<body bgcolor="white">
|
|
<script type="text/javascript" language="JavaScript" src="../jscript/codes.js">
|
|
</script>
|
|
|
|
<basefont size="3"> <a name="pthread_rwlock_destroy"></a> <a name="tag_03_555"></a><!-- pthread_rwlock_destroy -->
|
|
<!--header start-->
|
|
<center><font size="2">The Open Group Base Specifications Issue 6<br>
|
|
IEEE Std 1003.1-2001<br>
|
|
Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
|
|
|
|
<!--header end-->
|
|
<hr size="2" noshade>
|
|
<h4><a name="tag_03_555_01"></a>NAME</h4>
|
|
|
|
<blockquote>pthread_rwlock_destroy, pthread_rwlock_init - destroy and initialize a read-write lock object</blockquote>
|
|
|
|
<h4><a name="tag_03_555_02"></a>SYNOPSIS</h4>
|
|
|
|
<blockquote class="synopsis">
|
|
<div class="box"><code><tt><sup>[<a href="javascript:open_code('THR')">THR</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_rwlock_destroy(pthread_rwlock_t *</tt><i>rwlock</i><tt>);<br>
|
|
int pthread_rwlock_init(pthread_rwlock_t *restrict</tt> <i>rwlock</i><tt>,<br>
|
|
const pthread_rwlockattr_t *restrict</tt> <i>attr</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_555_03"></a>DESCRIPTION</h4>
|
|
|
|
<blockquote>
|
|
<p>The <i>pthread_rwlock_destroy</i>() function shall destroy the read-write lock object referenced by <i>rwlock</i> and release
|
|
any resources used by the lock. The effect of subsequent use of the lock is undefined until the lock is reinitialized by another
|
|
call to <i>pthread_rwlock_init</i>(). An implementation may cause <i>pthread_rwlock_destroy</i>() to set the object referenced by
|
|
<i>rwlock</i> to an invalid value. Results are undefined if <i>pthread_rwlock_destroy</i>() is called when any thread holds
|
|
<i>rwlock</i>. Attempting to destroy an uninitialized read-write lock results in undefined behavior.</p>
|
|
|
|
<p>The <i>pthread_rwlock_init</i>() function shall allocate any resources required to use the read-write lock referenced by
|
|
<i>rwlock</i> and initializes the lock to an unlocked state with attributes referenced by <i>attr</i>. If <i>attr</i> is NULL, the
|
|
default read-write lock attributes shall be used; the effect is the same as passing the address of a default read-write lock
|
|
attributes object. Once initialized, the lock can be used any number of times without being reinitialized. Results are undefined if
|
|
<i>pthread_rwlock_init</i>() is called specifying an already initialized read-write lock. Results are undefined if a read-write
|
|
lock is used without first being initialized.</p>
|
|
|
|
<p>If the <i>pthread_rwlock_init</i>() function fails, <i>rwlock</i> shall not be initialized and the contents of <i>rwlock</i> are
|
|
undefined.</p>
|
|
|
|
<p>Only the object referenced by <i>rwlock</i> may be used for performing synchronization. The result of referring to copies of
|
|
that object in calls to <i>pthread_rwlock_destroy</i>(), <a href=
|
|
"../functions/pthread_rwlock_rdlock.html"><i>pthread_rwlock_rdlock</i>()</a>, <a href=
|
|
"../functions/pthread_rwlock_timedrdlock.html"><i>pthread_rwlock_timedrdlock</i>()</a>, <a href=
|
|
"../functions/pthread_rwlock_timedwrlock.html"><i>pthread_rwlock_timedwrlock</i>()</a>, <a href=
|
|
"../functions/pthread_rwlock_tryrdlock.html"><i>pthread_rwlock_tryrdlock</i>()</a>, <a href=
|
|
"../functions/pthread_rwlock_trywrlock.html"><i>pthread_rwlock_trywrlock</i>()</a>, <a href=
|
|
"../functions/pthread_rwlock_unlock.html"><i>pthread_rwlock_unlock</i>()</a>, or <a href=
|
|
"../functions/pthread_rwlock_wrlock.html"><i>pthread_rwlock_wrlock</i>()</a> is undefined.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_555_04"></a>RETURN VALUE</h4>
|
|
|
|
<blockquote>
|
|
<p>If successful, the <i>pthread_rwlock_destroy</i>() and <i>pthread_rwlock_init</i>() functions shall return zero; otherwise, an
|
|
error number shall be returned to indicate the error.</p>
|
|
|
|
<p>The [EBUSY] and [EINVAL] error checks, if implemented, act as if they were performed immediately at the beginning of processing
|
|
for the function and caused an error return prior to modifying the state of the read-write lock specified by <i>rwlock</i>.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_555_05"></a>ERRORS</h4>
|
|
|
|
<blockquote>
|
|
<p>The <i>pthread_rwlock_destroy</i>() function may fail if:</p>
|
|
|
|
<dl compact>
|
|
<dt>[EBUSY]</dt>
|
|
|
|
<dd>The implementation has detected an attempt to destroy the object referenced by <i>rwlock</i> while it is locked.</dd>
|
|
|
|
<dt>[EINVAL]</dt>
|
|
|
|
<dd>The value specified by <i>rwlock</i> is invalid.</dd>
|
|
</dl>
|
|
|
|
<p>The <i>pthread_rwlock_init</i>() function shall fail if:</p>
|
|
|
|
<dl compact>
|
|
<dt>[EAGAIN]</dt>
|
|
|
|
<dd>The system lacked the necessary resources (other than memory) to initialize another read-write lock.</dd>
|
|
|
|
<dt>[ENOMEM]</dt>
|
|
|
|
<dd>Insufficient memory exists to initialize the read-write lock.</dd>
|
|
|
|
<dt>[EPERM]</dt>
|
|
|
|
<dd>The caller does not have the privilege to perform the operation.</dd>
|
|
</dl>
|
|
|
|
<p>The <i>pthread_rwlock_init</i>() function may fail if:</p>
|
|
|
|
<dl compact>
|
|
<dt>[EBUSY]</dt>
|
|
|
|
<dd>The implementation has detected an attempt to reinitialize the object referenced by <i>rwlock</i>, a previously initialized but
|
|
not yet destroyed read-write lock.</dd>
|
|
|
|
<dt>[EINVAL]</dt>
|
|
|
|
<dd>The value specified by <i>attr</i> is invalid.</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_555_06"></a>EXAMPLES</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_555_07"></a>APPLICATION USAGE</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_555_08"></a>RATIONALE</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_555_09"></a>FUTURE DIRECTIONS</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_555_10"></a>SEE ALSO</h4>
|
|
|
|
<blockquote>
|
|
<p><a href="pthread_rwlock_rdlock.html"><i>pthread_rwlock_rdlock</i>()</a> , <a href=
|
|
"pthread_rwlock_timedrdlock.html"><i>pthread_rwlock_timedrdlock</i>()</a> , <a href=
|
|
"pthread_rwlock_timedwrlock.html"><i>pthread_rwlock_timedwrlock</i>()</a> , <a href=
|
|
"pthread_rwlock_tryrdlock.html"><i>pthread_rwlock_tryrdlock</i>()</a> , <a href=
|
|
"pthread_rwlock_trywrlock.html"><i>pthread_rwlock_trywrlock</i>()</a> , <a href=
|
|
"pthread_rwlock_unlock.html"><i>pthread_rwlock_unlock</i>()</a> , <a href=
|
|
"pthread_rwlock_wrlock.html"><i>pthread_rwlock_wrlock</i>()</a> , the Base Definitions volume of IEEE Std 1003.1-2001, <a
|
|
href="../basedefs/pthread.h.html"><i><pthread.h></i></a></p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_555_11"></a>CHANGE HISTORY</h4>
|
|
|
|
<blockquote>
|
|
<p>First released in Issue 5.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_555_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 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). The
|
|
initializer macro is also deleted from the SYNOPSIS.</p>
|
|
</li>
|
|
|
|
<li>
|
|
<p>The DESCRIPTION is updated as follows:</p>
|
|
|
|
<ul>
|
|
<li>
|
|
<p>It explicitly notes allocation of resources upon initialization of a read-write lock object.</p>
|
|
</li>
|
|
|
|
<li>
|
|
<p>A paragraph is added specifying that copies of read-write lock objects may not be used.</p>
|
|
</li>
|
|
</ul>
|
|
</li>
|
|
|
|
<li>
|
|
<p>An [EINVAL] error is added to the ERRORS section for <i>pthread_rwlock_init</i>(), indicating that the <i>rwlock</i> value is
|
|
invalid.</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_rwlock_init</i>() prototype for alignment with the ISO/IEC 9899:1999
|
|
standard.</p>
|
|
</blockquote>
|
|
|
|
<div class="box"><em>End of informative text.</em></div>
|
|
|
|
<hr>
|
|
<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>
|
|
|