Adding upstream version 252.22.upstream/252.22upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 142 insertions, 0 deletions

diff --git a/man/sd_event_source_set_prepare.xml b/man/sd_event_source_set_prepare.xml
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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-or-later -->
+
+<refentry id="sd_event_source_set_prepare" xmlns:xi="http://www.w3.org/2001/XInclude">
+
+  <refentryinfo>
+    <title>sd_event_source_set_prepare</title>
+    <productname>systemd</productname>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>sd_event_source_set_prepare</refentrytitle>
+    <manvolnum>3</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>sd_event_source_set_prepare</refname>
+
+    <refpurpose>Set a preparation callback for event sources</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcsynopsisinfo>#include &lt;systemd/sd-event.h&gt;</funcsynopsisinfo>
+
+      <funcprototype>
+        <funcdef>int <function>sd_event_source_set_prepare</function></funcdef>
+        <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
+        <paramdef>sd_event_handler_t <parameter>callback</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>typedef int (*<function>sd_event_handler_t</function>)</funcdef>
+        <paramdef>sd_event_source *<parameter>s</parameter></paramdef>
+        <paramdef>void *<parameter>userdata</parameter></paramdef>
+      </funcprototype>
+
+    </funcsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para><function>sd_event_source_set_prepare()</function> may be
+    used to set a preparation callback for the event source object
+    specified as <parameter>source</parameter>. The callback function
+    specified as <parameter>callback</parameter> will be invoked
+    immediately before the event loop goes to sleep to wait for
+    incoming events. It is invoked with the user data pointer passed
+    when the event source was created. The event source will be disabled
+    if the callback function returns a negative error code. The callback
+    function may be used to reconfigure the precise events to wait for.
+    If the <parameter>callback</parameter> parameter is passed as <constant>NULL</constant>
+    the callback function is reset. </para>
+
+    <para>Event source objects have no preparation callback associated
+    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>. Preparation
+    callback functions are supported for all event source types with
+    the exception of those created with
+    <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Preparation
+    callback functions are dispatched in the order indicated by the
+    event source's priority field, as set with
+    <citerefentry><refentrytitle>sd_event_source_set_priority</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Preparation
+    callbacks of disabled event sources (see
+    <citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>)
+    are not invoked.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Return Value</title>
+
+    <para>On success, <function>sd_event_source_set_prepare()</function> returns a non-negative integer. On
+    failure, it returns a negative errno-style error code.</para>
+
+    <refsect2>
+      <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>-ESTALE</constant></term>
+
+          <listitem><para>The event loop is already terminated.</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>
+
+        <varlistentry>
+          <term><constant>-EDOM</constant></term>
+
+          <listitem><para>The specified event source has been created with
+          <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
+
+        </varlistentry>
+
+      </variablelist>
+    </refsect2>
+  </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_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_source_set_priority</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+
+</refentry>