mirror of
https://github.com/systemd/systemd-stable.git
synced 2024-12-24 21:34:08 +03:00
7c071fda94
The list of man pages is auto generated, based on conditonal='...' attributes in the man page itself.
184 lines
8.6 KiB
XML
184 lines
8.6 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
|
||
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
||
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
||
|
||
<!--
|
||
This file is part of systemd.
|
||
|
||
Copyright 2013 Lennart Poettering
|
||
|
||
systemd is free software; you can redistribute it and/or modify it
|
||
under the terms of the GNU Lesser General Public License as published by
|
||
the Free Software Foundation; either version 2.1 of the License, or
|
||
(at your option) any later version.
|
||
|
||
systemd is distributed in the hope that it will be useful, but
|
||
WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
Lesser General Public License for more details.
|
||
|
||
You should have received a copy of the GNU Lesser General Public License
|
||
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
||
-->
|
||
|
||
<refentry id="sd_bus_message_get_monotonic_usec" conditional="ENABLE_KDBUS">
|
||
|
||
<refentryinfo>
|
||
<title>sd_bus_message_get_monotonic_usec</title>
|
||
<productname>systemd</productname>
|
||
|
||
<authorgroup>
|
||
<author>
|
||
<contrib>Developer</contrib>
|
||
<firstname>Lennart</firstname>
|
||
<surname>Poettering</surname>
|
||
<email>lennart@poettering.net</email>
|
||
</author>
|
||
</authorgroup>
|
||
</refentryinfo>
|
||
|
||
<refmeta>
|
||
<refentrytitle>sd_bus_message_get_monotonic_usec</refentrytitle>
|
||
<manvolnum>3</manvolnum>
|
||
</refmeta>
|
||
|
||
<refnamediv>
|
||
<refname>sd_bus_message_get_monotonic_usec</refname>
|
||
<refname>sd_bus_message_get_realtime_usec</refname>
|
||
<refname>sd_bus_message_get_seqnum</refname>
|
||
<refpurpose>Retrieve the sender timestamps and sequence number of a message</refpurpose>
|
||
</refnamediv>
|
||
|
||
<refsynopsisdiv>
|
||
<funcsynopsis>
|
||
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_message_get_monotonic_usec</function></funcdef>
|
||
<paramdef>sd_bus_message *<parameter>message</parameter></paramdef>
|
||
<paramdef>uint64_t *<parameter>usec</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_message_get_realtime_usec</function></funcdef>
|
||
<paramdef>sd_bus_message *<parameter>message</parameter></paramdef>
|
||
<paramdef>uint64_t *<parameter>usec</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_message_get_seqnum</function></funcdef>
|
||
<paramdef>sd_bus_message *<parameter>message</parameter></paramdef>
|
||
<paramdef>uint64_t *<parameter>seqnum</parameter></paramdef>
|
||
</funcprototype>
|
||
</funcsynopsis>
|
||
</refsynopsisdiv>
|
||
|
||
<refsect1>
|
||
<title>Description</title>
|
||
|
||
<para><function>sd_bus_message_get_monotonic_usec()</function>
|
||
returns the monotonic timestamp of the time the
|
||
message was sent. This value is in microseconds since
|
||
the <literal>CLOCK_MONOTONIC</literal> epoch, see
|
||
<citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
||
for details.</para>
|
||
|
||
<para>Similar,
|
||
<function>sd_bus_message_get_realtime_usec()</function>
|
||
returns the realtime (wallclock) timestamp of the time
|
||
the message was sent. This value is in microseconds
|
||
since Jan 1st, 1970, i.e. in the
|
||
<literal>CLOCK_REALTIME</literal> clock.</para>
|
||
|
||
<para><function>sd_bus_message_get_seqnum()</function>
|
||
returns the kernel-assigned sequence number of the
|
||
message. The kernel assigns a global monotonically increasing
|
||
sequence number to all messages sent on the local
|
||
system. This sequence number is useful for determining
|
||
message send order, even across different busses of
|
||
the local system. The sequence number combined with
|
||
the boot ID of the system (as returned by
|
||
<citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>)
|
||
is a suitable globally unique identifier for bus
|
||
messages.</para>
|
||
|
||
<para>These timestamps and the sequence number are
|
||
attached to each message by the kernel and cannot be
|
||
manipulated by the sender.</para>
|
||
|
||
<para>Note that these timestamps are only available on
|
||
some bus transports, and only after support for them
|
||
has been negotiated with the
|
||
<citerefentry><refentrytitle>sd_bus_negotiate_timestamp</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||
call.</para>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>Return Value</title>
|
||
|
||
<para>On success, these calls return 0 or a positive
|
||
integer. On failure, these calls return a negative
|
||
errno-style error code.</para>
|
||
|
||
<para>On success, the timestamp or sequence number is
|
||
returned in the specified 64-bit unsigned integer
|
||
variable.</para>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>Errors</title>
|
||
|
||
<para>Returned errors may indicate the following problems:</para>
|
||
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term><varname>-EINVAL</varname></term>
|
||
|
||
<listitem><para>A specified parameter
|
||
is invalid.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>-ENODATA</varname></term>
|
||
|
||
<listitem><para>No timestamp or
|
||
sequence number information is
|
||
attached to the passed message. This
|
||
error is returned if the underlying
|
||
transport does not support
|
||
timestamping or assigning of sequence
|
||
numbers, or if this feature has not
|
||
been negotiated with
|
||
<citerefentry><refentrytitle>sd_bus_negotiate_timestamp</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>Notes</title>
|
||
|
||
<para>The
|
||
<function>sd_bus_message_get_monotonic_usec()</function>,
|
||
<function>sd_bus_message_get_realtime_usec()</function>,
|
||
and <function>sd_bus_message_get_seqnum()</function>
|
||
interfaces are available as a shared library, which
|
||
can be compiled and linked to with the
|
||
<constant>libsystemd</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
||
file.</para>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>See Also</title>
|
||
|
||
<para>
|
||
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd_bus_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd_bus_negotiate_timestamp</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||
</para>
|
||
</refsect1>
|
||
|
||
</refentry>
|