📄 mq_getattr.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><!-- Copyright 1997 The Open Group, All Rights Reserved --><title>mq_getattr</title></head><body bgcolor=white><center><font size=2>The Single UNIX ® Specification, Version 2<br>Copyright © 1997 The Open Group</font></center><hr size=2 noshade><h4><a name = "tag_000_007_734"> </a>NAME</h4><blockquote>mq_getattr - get message queue attributes(<b>REALTIME</b>)</blockquote><h4><a name = "tag_000_007_735"> </a>SYNOPSIS</h4><blockquote><pre><code>#include <<a href="mqueue.h.html">mqueue.h</a>>int mq_getattr(mqd_t <i>mqdes</i>, struct mq_attr *<i>mqstat</i>);</code></pre></blockquote><h4><a name = "tag_000_007_736"> </a>DESCRIPTION</h4><blockquote>The<i>mqdes</i>argument specifies a message queue descriptor.The<i>mq_getattr()</i>function is used to get status information and attributes of the messagequeue and the open message queue description associated with the messagequeue descriptor.The results are returned in the <i>mq_attr</i>structure referenced by the<i>mqstat</i>argument.<p>Upon return, the following members will have the values associated with theopen message queue description as set when the message queue was opened and asmodified by subsequent<i><a href="mq_setattr.html">mq_setattr()</a></i>calls:<dl compact><dt>mq_flags<dd></dl><p>The following attributes of the message queue are returnedas set at message queue creation.<dl compact><dt>mq_maxmsg<dd><dt>mq_msgsize<dd><dt>mq_curmsgs<dd>The number of messages currently on the queue.</dl></blockquote><h4><a name = "tag_000_007_737"> </a>RETURN VALUE</h4><blockquote>Upon successful completion, the<i>mq_getattr()</i>function returns zero.Otherwise, the function returns -1 and sets<i>errno</i>to indicate the error.</blockquote><h4><a name = "tag_000_007_738"> </a>ERRORS</h4><blockquote>The <i>mq_getattr()</i>function will fail if:<dl compact><dt>[EBADF]<dd>The<i>mqdes</i>argument is not a valid message queue descriptor.<dt>[ENOSYS]<dd>The function<i>mq_getattr()</i>is not supported by this implementation.</dl></blockquote><h4><a name = "tag_000_007_739"> </a>EXAMPLES</h4><blockquote>None.</blockquote><h4><a name = "tag_000_007_740"> </a>APPLICATION USAGE</h4><blockquote>None.</blockquote><h4><a name = "tag_000_007_741"> </a>SEE ALSO</h4><blockquote><i><a href="mq_open.html">mq_open()</a></i>,<i><a href="mq_send.html">mq_send()</a></i>,<i><a href="mq_setattr.html">mq_setattr()</a></i><i><a href="mqueue.h.html"><mqueue.h></a></i>,<i><a href="msgctl.html">msgctl()</a></i>,<i><a href="msgget.html">msgget()</a></i>,<i><a href="msgrcv.html">msgrcv()</a></i>,<i><a href="msgsnd.html">msgsnd()</a></i>.</blockquote><h4>DERIVATION</h4><blockquote>Derived from the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995)</blockquote><hr size=2 noshade><center><font size=2>UNIX ® is a registered Trademark of The Open Group.<br>Copyright © 1997 The Open Group<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]</font></center><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 + -