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Diffstat (limited to 'man/sd_event_source_set_enabled.xml')
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diff --git a/man/sd_event_source_set_enabled.xml b/man/sd_event_source_set_enabled.xml new file mode 100644 index 0000000..73f0184 --- /dev/null +++ b/man/sd_event_source_set_enabled.xml @@ -0,0 +1,158 @@ +<?xml version='1.0'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" +"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + +<!-- + SPDX-License-Identifier: LGPL-2.1+ +--> + +<refentry id="sd_event_source_set_enabled" xmlns:xi="http://www.w3.org/2001/XInclude"> + + <refentryinfo> + <title>sd_event_source_set_enabled</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>sd_event_source_set_enabled</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_event_source_set_enabled</refname> + <refname>sd_event_source_get_enabled</refname> + <refname>SD_EVENT_ON</refname> + <refname>SD_EVENT_OFF</refname> + <refname>SD_EVENT_ONESHOT</refname> + + <refpurpose>Enable or disable event sources</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> + + <funcsynopsisinfo><token>enum</token> { + <constant>SD_EVENT_OFF</constant> = 0, + <constant>SD_EVENT_ON</constant> = 1, + <constant>SD_EVENT_ONESHOT</constant> = -1, +};</funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_event_source_set_enabled</function></funcdef> + <paramdef>sd_event_source *<parameter>source</parameter></paramdef> + <paramdef>int <parameter>enabled</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_event_source_get_enabled</function></funcdef> + <paramdef>sd_event_source *<parameter>source</parameter></paramdef> + <paramdef>int *<parameter>enabled</parameter></paramdef> + </funcprototype> + + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><function>sd_event_source_set_enabled()</function> may be + used to enable or disable the event source object specified as + <parameter>source</parameter>. The <parameter>enabled</parameter> + parameter takes one of <constant>SD_EVENT_ON</constant> (to + enable), <constant>SD_EVENT_OFF</constant> (to disable) or + <constant>SD_EVENT_ONESHOT</constant>. If invoked with + <constant>SD_EVENT_ONESHOT</constant> the event source will be + enabled but automatically reset to + <constant>SD_EVENT_OFF</constant> after the event source was + dispatched once.</para> + + <para>Event sources that are disabled will not result in event + loop wakeups and will not be dispatched, until they are enabled + again.</para> + + <para><function>sd_event_source_get_enabled()</function> may be + used to query whether the event source object + <parameter>source</parameter> is currently enabled or not. It + returns the enablement state (one of <constant>SD_EVENT_ON</constant>, + <constant>SD_EVENT_OFF</constant>, <constant>SD_EVENT_ONESHOT</constant>) + in <parameter>enabled</parameter>, if it is not <constant>NULL</constant>. + It also returns true if the event source is not disabled.</para> + + <para>Event source objects are enabled when they are first created + with calls such as + <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>. However, + depending on the event source type they are enabled continuously + (<constant>SD_EVENT_ON</constant>) or only for a single invocation + of the event source handler + (<constant>SD_EVENT_ONESHOT</constant>). For details see the + respective manual pages.</para> + + <para>As event source objects stay active and may be dispatched as + long as there is at least one reference to them, in many cases it + is a good idea to combine a call to + <citerefentry><refentrytitle>sd_event_source_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry> + with a prior call to + <function>sd_event_source_set_enabled()</function> with + <constant>SD_EVENT_OFF</constant>, to ensure the event source is + not dispatched again until all other remaining references are dropped.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, <function>sd_event_source_set_enabled()</function> returns a non-negative + integer. <function>sd_event_source_get_enabled()</function> returns zero if the source is + disabled (<constant>SD_EVENT_OFF</constant>) and a positive integer otherwise. On failure, they + return a negative errno-style error code.</para> + </refsect1> + + <refsect1> + <title>Errors</title> + + <para>Returned errors may indicate the following problems:</para> + + <variablelist> + <varlistentry> + <term><constant>-EINVAL</constant></term> + + <listitem><para><parameter>source</parameter> is not a valid + pointer to an <structname>sd_event_source</structname> + object.</para></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-ENOMEM</constant></term> + + <listitem><para>Not enough memory.</para></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-ECHILD</constant></term> + + <listitem><para>The event loop has been created in a different process.</para></listitem> + + </varlistentry> + + </variablelist> + </refsect1> + + <xi:include href="libsystemd-pkgconfig.xml" /> + + <refsect1> + <title>See Also</title> + + <para> + <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_add_time</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_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |