-<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
-"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
-
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- Copyright 2014 Lennart Poettering
-
- systemd is free software; you can redistribute it and/or modify it
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--->
+<?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+ -->
<refentry id="sd_event_add_time" xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_event_add_time</title>
<productname>systemd</productname>
-
- <authorgroup>
- <author>
- <contrib>Developer</contrib>
- <firstname>Lennart</firstname>
- <surname>Poettering</surname>
- <email>lennart@poettering.net</email>
- </author>
- </authorgroup>
</refentryinfo>
<refmeta>
<refsect1>
<title>Description</title>
- <para><function>sd_event_add_time()</function> adds a new timer
- event source to an event loop. The event loop object is specified
- in the <parameter>event</parameter> parameter, the event source
- object is returned in the <parameter>source</parameter>
- parameter. The <parameter>clock</parameter> parameter takes a
- clock identifier, one of <constant>CLOCK_REALTIME</constant>,
- <constant>CLOCK_MONOTONIC</constant>,
- <constant>CLOCK_BOOTTIME</constant>,
- <constant>CLOCK_REALTIME_ALARM</constant>, or
- <constant>CLOCK_BOOTTIME_ALARM</constant>. See
- <citerefentry><refentrytitle>timerfd_create</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details regarding the various types of clocks. The
- <parameter>usec</parameter> parameter specifies the earliest time,
- in microseconds (µs), relative to the clock's epoch, when
- the timer shall be triggered. If a time already in the past is
- specified (including <constant>0</constant>), this timer source
- "fires" immediately and is ready to be dispatched. The
- <parameter>accuracy</parameter> parameter specifies an additional
- accuracy value in µs specifying how much the timer event may be
- delayed. Use <constant>0</constant> to select the default accuracy
- (250ms). Use 1µs for maximum accuracy. Consider specifying
- 60000000µs (1min) or larger for long-running events that may be
- delayed substantially. Picking higher accuracy values allows the
- system to coalesce timer events more aggressively, improving
- power efficiency. The <parameter>handler</parameter> parameter
- shall reference a function to call when the timer elapses. The
- handler function will be passed the
- <parameter>userdata</parameter> pointer, which may be chosen
- freely by the caller. The handler is also passed the configured
- trigger time, even if it is actually called
- slightly later, subject to the specified accuracy value,
- the kernel timer slack (see
- <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>),
- and additional scheduling latencies. To query the actual time the
- handler was called use
+ <para><function>sd_event_add_time()</function> adds a new timer event source to an event loop. The event loop
+ object is specified in the <parameter>event</parameter> parameter, the event source object is returned in the
+ <parameter>source</parameter> parameter. The <parameter>clock</parameter> parameter takes a clock identifier, one
+ of <constant>CLOCK_REALTIME</constant>, <constant>CLOCK_MONOTONIC</constant>, <constant>CLOCK_BOOTTIME</constant>,
+ <constant>CLOCK_REALTIME_ALARM</constant>, or <constant>CLOCK_BOOTTIME_ALARM</constant>. See
+ <citerefentry><refentrytitle>timerfd_create</refentrytitle><manvolnum>2</manvolnum></citerefentry> for details
+ regarding the various types of clocks. The <parameter>usec</parameter> parameter specifies the earliest time, in
+ microseconds (µs), relative to the clock's epoch, when the timer shall be triggered. If a time already in the past
+ is specified (including <constant>0</constant>), this timer source "fires" immediately and is ready to be
+ dispatched. If the parameter is specified as <constant>UINT64_MAX</constant> the timer event will never elapse,
+ which may be used as an alternative to explicitly disabling a timer event source with
+ <citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>. The
+ <parameter>accuracy</parameter> parameter specifies an additional accuracy value in µs specifying how much the
+ timer event may be delayed. Use <constant>0</constant> to select the default accuracy (250ms). Use 1µs for maximum
+ accuracy. Consider specifying 60000000µs (1min) or larger for long-running events that may be delayed
+ substantially. Picking higher accuracy values allows the system to coalesce timer events more aggressively,
+ improving power efficiency. The <parameter>handler</parameter> parameter shall reference a function to call when
+ the timer elapses. The handler function will be passed the <parameter>userdata</parameter> pointer, which may be
+ chosen freely by the caller. The handler is also passed the configured trigger time, even if it is actually called
+ slightly later, subject to the specified accuracy value, the kernel timer slack (see
+ <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>), and additional
+ scheduling latencies. To query the actual time the handler was called use
<citerefentry><refentrytitle>sd_event_now</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
<para>By default, the timer will elapse once
in µs.</para>
<para><function>sd_event_source_get_time_accuracy()</function>
- retrieves the configured accuracy value of a event source
+ retrieves the configured accuracy value of an event source
created previously with <function>sd_event_add_time()</function>. It
takes the event source object and a pointer to a variable to store
the accuracy in. The accuracy is specified in µs.</para>
the event source object and accuracy, in µs.</para>
<para><function>sd_event_source_get_time_clock()</function>
- retrieves the configured clock of a event source created
+ retrieves the configured clock of an event source created
previously with <function>sd_event_add_time()</function>. It takes
the event source object and a pointer to a variable to store the
clock identifier in.</para>
<para>On success, these functions return 0 or a positive
integer. On failure, they return a negative errno-style error
code. </para>
- </refsect1>
- <refsect1>
- <title>Errors</title>
+ <refsect2>
+ <title>Errors</title>
- <para>Returned values may indicate the following problems:</para>
+ <para>Returned values may indicate the following problems:</para>
- <variablelist>
- <varlistentry>
- <term><constant>-ENOMEM</constant></term>
+ <variablelist>
+ <varlistentry>
+ <term><constant>-ENOMEM</constant></term>
- <listitem><para>Not enough memory to allocate an object.</para></listitem>
- </varlistentry>
+ <listitem><para>Not enough memory to allocate an object.</para></listitem>
+ </varlistentry>
- <varlistentry>
- <term><constant>-EINVAL</constant></term>
+ <varlistentry>
+ <term><constant>-EINVAL</constant></term>
- <listitem><para>An invalid argument has been passed.</para></listitem>
+ <listitem><para>An invalid argument has been passed.</para></listitem>
- </varlistentry>
+ </varlistentry>
- <varlistentry>
- <term><constant>-ESTALE</constant></term>
+ <varlistentry>
+ <term><constant>-ESTALE</constant></term>
- <listitem><para>The event loop is already terminated.</para></listitem>
+ <listitem><para>The event loop is already terminated.</para></listitem>
- </varlistentry>
+ </varlistentry>
- <varlistentry>
- <term><constant>-ECHILD</constant></term>
+ <varlistentry>
+ <term><constant>-ECHILD</constant></term>
- <listitem><para>The event loop has been created in a different process.</para></listitem>
+ <listitem><para>The event loop has been created in a different process.</para></listitem>
- </varlistentry>
+ </varlistentry>
- <varlistentry>
- <term><constant>-EOPNOTSUPP</constant></term>
+ <varlistentry>
+ <term><constant>-EOPNOTSUPP</constant></term>
- <listitem><para>The selected clock is not supported by the event loop implementation.</para></listitem>
+ <listitem><para>The selected clock is not supported by the event loop implementation.</para></listitem>
- </varlistentry>
+ </varlistentry>
- <varlistentry>
- <term><constant>-EDOM</constant></term>
+ <varlistentry>
+ <term><constant>-EDOM</constant></term>
- <listitem><para>The passed event source is not a timer event source.</para></listitem>
- </varlistentry>
- </variablelist>
+ <listitem><para>The passed event source is not a timer event source.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect2>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_event_add_inotify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_source_set_priority</refentrytitle><manvolnum>3</manvolnum></citerefentry>,