mirror of
https://github.com/systemd/systemd.git
synced 2024-10-30 14:55:37 +03:00
115 lines
4.2 KiB
XML
115 lines
4.2 KiB
XML
<?xml version='1.0'?>
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
|
|
|
|
<refentry id="sd_event_now" xmlns:xi="http://www.w3.org/2001/XInclude">
|
|
|
|
<refentryinfo>
|
|
<title>sd_event_now</title>
|
|
<productname>systemd</productname>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>sd_event_now</refentrytitle>
|
|
<manvolnum>3</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>sd_event_now</refname>
|
|
|
|
<refpurpose>Retrieve current event loop iteration timestamp</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<funcsynopsis>
|
|
<funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo>
|
|
|
|
<funcprototype>
|
|
<funcdef>int <function>sd_event_now</function></funcdef>
|
|
<paramdef>sd_event *<parameter>event</parameter></paramdef>
|
|
<paramdef>clockid_t <parameter>clock</parameter></paramdef>
|
|
<paramdef>uint64_t *<parameter>usec</parameter></paramdef>
|
|
</funcprototype>
|
|
|
|
</funcsynopsis>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para><function>sd_event_now()</function> returns the time when
|
|
the most recent event loop iteration began. A timestamp
|
|
is taken right after returning from the event sleep, and before
|
|
dispatching any event sources. The <parameter>event</parameter>
|
|
parameter specifies the event loop object to retrieve the timestamp
|
|
from. The <parameter>clock</parameter> parameter specifies the clock to
|
|
retrieve the timestamp for, and is one of
|
|
<constant>CLOCK_REALTIME</constant> (or equivalently
|
|
<constant>CLOCK_REALTIME_ALARM</constant>),
|
|
<constant>CLOCK_MONOTONIC</constant>, or
|
|
<constant>CLOCK_BOOTTIME</constant> (or equivalently
|
|
<constant>CLOCK_BOOTTIME_ALARM</constant>), see
|
|
<citerefentry project='man-pages'><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
for more information on the various clocks. The retrieved
|
|
timestamp is stored in the <parameter>usec</parameter> parameter,
|
|
in µs since the clock's epoch. If this function is invoked before
|
|
the first event loop iteration, the current time is returned, as
|
|
reported by <function>clock_gettime()</function>. To distinguish
|
|
this case from a regular invocation the return value will be
|
|
positive, and zero when the returned timestamp refers to an actual
|
|
event loop iteration.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Return Value</title>
|
|
|
|
<para>If the first event loop iteration has not run yet <function>sd_event_now()</function> writes
|
|
current time to <parameter>usec</parameter> and returns a positive return value. Otherwise, it will
|
|
write the requested timestamp to <parameter>usec</parameter> and return 0. On failure, the call returns a
|
|
negative errno-style error code.</para>
|
|
|
|
<refsect2>
|
|
<title>Errors</title>
|
|
|
|
<para>Returned values may indicate the following problems:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><constant>-EINVAL</constant></term>
|
|
|
|
<listitem><para>An invalid parameter was passed.</para></listitem>
|
|
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><constant>-EOPNOTSUPP</constant></term>
|
|
|
|
<listitem><para>Unsupported clock type.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><constant>-ECHILD</constant></term>
|
|
|
|
<listitem><para>The event loop object was created in a different process.</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect2>
|
|
</refsect1>
|
|
|
|
<xi:include href="libsystemd-pkgconfig.xml" />
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
|
|
<para>
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry project='man-pages'><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|