📄 mq_notify.html
字号:
<!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>mq_notify</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="mq_notify"></a> <a name="tag_03_384"></a><!-- mq_notify --> <!--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_384_01"></a>NAME</h4><blockquote>mq_notify - notify process that a message is available (<b>REALTIME</b>)</blockquote><h4><a name="tag_03_384_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><div class="box"><code><tt><sup>[<a href="javascript:open_code('MSG')">MSG</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> #include <<a href="../basedefs/mqueue.h.html">mqueue.h</a>><br><br> int mq_notify(mqd_t</tt> <i>mqdes</i><tt>, const struct sigevent *</tt><i>notification</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_384_03"></a>DESCRIPTION</h4><blockquote><p>If the argument <i>notification</i> is not NULL, this function shall register the calling process to be notified of messagearrival at an empty message queue associated with the specified message queue descriptor, <i>mqdes</i>. The notification specifiedby the <i>notification</i> argument shall be sent to the process when the message queue transitions from empty to non-empty. At anytime, only one process may be registered for notification by a message queue. If the calling process or any other process hasalready registered for notification of message arrival at the specified message queue, subsequent attempts to register for thatmessage queue shall fail.</p><p>If <i>notification</i> is NULL and the process is currently registered for notification by the specified message queue, theexisting registration shall be removed.</p><p>When the notification is sent to the registered process, its registration shall be removed. The message queue shall then beavailable for registration.</p><p>If a process has registered for notification of message arrival at a message queue and some thread is blocked in <a href="../functions/mq_receive.html"><i>mq_receive</i>()</a> waiting to receive a message when a message arrives at the queue, thearriving message shall satisfy the appropriate <a href="../functions/mq_receive.html"><i>mq_receive</i>()</a>. The resultingbehavior is as if the message queue remains empty, and no notification shall be sent.</p></blockquote><h4><a name="tag_03_384_04"></a>RETURN VALUE</h4><blockquote><p>Upon successful completion, the <i>mq_notify</i>() function shall return a value of zero; otherwise, the function shall return avalue of -1 and set <i>errno</i> to indicate the error.</p></blockquote><h4><a name="tag_03_384_05"></a>ERRORS</h4><blockquote><p>The <i>mq_notify</i>() function shall fail if:</p><dl compact><dt>[EBADF]</dt><dd>The <i>mqdes</i> argument is not a valid message queue descriptor.</dd><dt>[EBUSY]</dt><dd>A process is already registered for notification by the message queue.</dd></dl></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_384_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_384_07"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_384_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_384_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_384_10"></a>SEE ALSO</h4><blockquote><p><a href="mq_open.html"><i>mq_open</i>()</a>, <a href="mq_send.html"><i>mq_send</i>()</a>, <a href="mq_timedsend.html"><i>mq_timedsend</i>()</a>, <a href="msgctl.html"><i>msgctl</i>()</a>, <a href="msgget.html"><i>msgget</i>()</a>, <a href="msgrcv.html"><i>msgrcv</i>()</a>, <a href="msgsnd.html"><i>msgsnd</i>()</a>, theBase Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/mqueue.h.html"><i><mqueue.h></i></a></p></blockquote><h4><a name="tag_03_384_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 5. Included for alignment with the POSIX Realtime Extension.</p></blockquote><h4><a name="tag_03_384_12"></a>Issue 6</h4><blockquote><p>The <i>mq_notify</i>() function is marked as part of the Message Passing option.</p><p>The [ENOSYS] error condition has been removed as stubs need not be provided if an implementation does not support the MessagePassing option.</p><p>The <a href="../functions/mq_timedsend.html"><i>mq_timedsend</i>()</a> function is added to the SEE ALSO section for alignmentwith IEEE Std 1003.1d-1999.</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
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -