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mq_timedsend.html
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<!-- Creator : groff version 1.22.4 -->
<!-- CreationDate: Wed Jan 29 11:25:43 2020 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta name="generator" content="groff -Thtml, see www.gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<meta name="Content-Style" content="text/css">
<style type="text/css">
p { margin-top: 0; margin-bottom: 0; vertical-align: top }
pre { margin-top: 0; margin-bottom: 0; vertical-align: top }
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h1 { text-align: center }
</style>
<title>MQ_SEND</title>
</head>
<body>
<h1 align="center">MQ_SEND</h1>
<a href="#NAME">NAME</a><br>
<a href="#SYNOPSIS">SYNOPSIS</a><br>
<a href="#DESCRIPTION">DESCRIPTION</a><br>
<a href="#RETURN VALUE">RETURN VALUE</a><br>
<a href="#ERRORS">ERRORS</a><br>
<a href="#ATTRIBUTES">ATTRIBUTES</a><br>
<a href="#CONFORMING TO">CONFORMING TO</a><br>
<a href="#NOTES">NOTES</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>
<a href="#COLOPHON">COLOPHON</a><br>
<hr>
<h2>NAME
<a name="NAME"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">mq_send,
mq_timedsend - send a message to a message queue</p>
<h2>SYNOPSIS
<a name="SYNOPSIS"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>#include
<mqueue.h></b></p>
<p style="margin-left:11%; margin-top: 1em"><b>int
mq_send(mqd_t</b> <i>mqdes</i><b>, const char
*</b><i>msg_ptr</i><b>, <br>
size_t</b> <i>msg_len</i><b>, unsigned int</b>
<i>msg_prio</i><b>);</b></p>
<p style="margin-left:11%; margin-top: 1em"><b>#include
<time.h> <br>
#include <mqueue.h></b></p>
<p style="margin-left:11%; margin-top: 1em"><b>int
mq_timedsend(mqd_t</b> <i>mqdes</i><b>, const char
*</b><i>msg_ptr</i><b>, <br>
size_t</b> <i>msg_len</i><b>, unsigned int</b>
<i>msg_prio</i><b>, <br>
const struct timespec *</b><i>abs_timeout</i><b>);</b></p>
<p style="margin-left:11%; margin-top: 1em">Link with
<i>-lrt</i>.</p>
<p style="margin-left:5%; margin-top: 1em">Feature Test
Macro Requirements for glibc (see
<b>feature_test_macros</b>(7)):</p>
<p style="margin-left:11%; margin-top: 1em"><b>mq_timedsend</b>():</p>
<p style="margin-left:17%;">_POSIX_C_SOURCE >= 200112L</p>
<h2>DESCRIPTION
<a name="DESCRIPTION"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>mq_send</b>()
adds the message pointed to by <i>msg_ptr</i> to the message
queue referred to by the message queue descriptor
<i>mqdes</i>. The <i>msg_len</i> argument specifies the
length of the message pointed to by <i>msg_ptr</i>; this
length must be less than or equal to the queue’s
<i>mq_msgsize</i> attribute. Zero-length messages are
allowed.</p>
<p style="margin-left:11%; margin-top: 1em">The
<i>msg_prio</i> argument is a nonnegative integer that
specifies the priority of this message. Messages are placed
on the queue in decreasing order of priority, with newer
messages of the same priority being placed after older
messages with the same priority. See <b>mq_overview</b>(7)
for details on the range for the message priority.</p>
<p style="margin-left:11%; margin-top: 1em">If the message
queue is already full (i.e., the number of messages on the
queue equals the queue’s <i>mq_maxmsg</i> attribute),
then, by default, <b>mq_send</b>() blocks until sufficient
space becomes available to allow the message to be queued,
or until the call is interrupted by a signal handler. If the
<b>O_NONBLOCK</b> flag is enabled for the message queue
description, then the call instead fails immediately with
the error <b>EAGAIN</b>.</p>
<p style="margin-left:11%; margin-top: 1em"><b>mq_timedsend</b>()
behaves just like <b>mq_send</b>(), except that if the queue
is full and the <b>O_NONBLOCK</b> flag is not enabled for
the message queue description, then <i>abs_timeout</i>
points to a structure which specifies how long the call will
block. This value is an absolute timeout in seconds and
nanoseconds since the Epoch, 1970-01-01 00:00:00 +0000
(UTC), specified in the following structure:</p>
<p style="margin-left:17%; margin-top: 1em">struct timespec
{ <br>
time_t tv_sec; /* seconds */ <br>
long tv_nsec; /* nanoseconds */ <br>
};</p>
<p style="margin-left:11%; margin-top: 1em">If the message
queue is full, and the timeout has already expired by the
time of the call, <b>mq_timedsend</b>() returns
immediately.</p>
<h2>RETURN VALUE
<a name="RETURN VALUE"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">On success,
<b>mq_send</b>() and <b>mq_timedsend</b>() return zero; on
error, -1 is returned, with <i>errno</i> set to indicate the
error.</p>
<h2>ERRORS
<a name="ERRORS"></a>
</h2>
<table width="100%" border="0" rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p style="margin-top: 1em"><b>EAGAIN</b></p></td>
<td width="2%"></td>
<td width="78%">
<p style="margin-top: 1em">The queue was full, and the
<b>O_NONBLOCK</b> flag was set for the message queue
description referred to by <i>mqdes</i>.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>EBADF</b></p></td>
<td width="2%"></td>
<td width="78%">
<p>The descriptor specified in <i>mqdes</i> was invalid or
not opened for writing.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>EINTR</b></p></td>
<td width="2%"></td>
<td width="78%">
<p>The call was interrupted by a signal handler; see
<b>signal</b>(7).</p> </td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>EINVAL</b></p></td>
<td width="2%"></td>
<td width="78%">
<p>The call would have blocked, and <i>abs_timeout</i> was
invalid, either because <i>tv_sec</i> was less than zero, or
because <i>tv_nsec</i> was less than zero or greater than
1000 million.</p></td></tr>
</table>
<p style="margin-left:11%;"><b>EMSGSIZE</b></p>
<p style="margin-left:22%;"><i>msg_len</i> was greater than
the <i>mq_msgsize</i> attribute of the message queue.</p>
<p style="margin-left:11%;"><b>ETIMEDOUT</b></p>
<p style="margin-left:22%;">The call timed out before a
message could be transferred.</p>
<h2>ATTRIBUTES
<a name="ATTRIBUTES"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">For an
explanation of the terms used in this section, see
<b>attributes</b>(7).</p>
<p align="center" style="margin-top: 1em"><img src="grohtml-489791.png" alt="Image grohtml-489791.png"></p>
<h2>CONFORMING TO
<a name="CONFORMING TO"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">POSIX.1-2001,
POSIX.1-2008.</p>
<h2>NOTES
<a name="NOTES"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">On Linux,
<b>mq_timedsend</b>() is a system call, and <b>mq_send</b>()
is a library function layered on top of that system
call.</p>
<h2>SEE ALSO
<a name="SEE ALSO"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>mq_close</b>(3),
<b>mq_getattr</b>(3), <b>mq_notify</b>(3),
<b>mq_open</b>(3), <b>mq_receive</b>(3),
<b>mq_unlink</b>(3), <b>mq_overview</b>(7),
<b>time</b>(7)</p>
<h2>COLOPHON
<a name="COLOPHON"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">This page is
part of release 5.02 of the Linux <i>man-pages</i> project.
A description of the project, information about reporting
bugs, and the latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.</p>
<hr>
</body>
</html>