chiark / gitweb /
man: fully document sd-event interfaces
[elogind.git] / man / sd_event_source_set_description.xml
diff --git a/man/sd_event_source_set_description.xml b/man/sd_event_source_set_description.xml
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+<?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">
+
+<!--
+  This file is part of elogind.
+
+  Copyright 2014 Zbigniew JÄ™drzejewski-Szmek
+
+  elogind 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.
+
+  elogind 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 elogind; If not, see <http://www.gnu.org/licenses/>.
+-->
+
+<refentry id="sd_event_source_set_description" xmlns:xi="http://www.w3.org/2001/XInclude">
+
+  <refentryinfo>
+    <title>sd_event_source_set_description</title>
+    <productname>elogind</productname>
+
+    <authorgroup>
+      <author>
+        <contrib>More text</contrib>
+        <firstname>Zbigniew</firstname>
+        <surname>JÄ™drzejewski-Szmek</surname>
+        <email>zbyszek@in.waw.pl</email>
+      </author>
+    </authorgroup>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>sd_event_source_set_description</refentrytitle>
+    <manvolnum>3</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>sd_event_source_set_description</refname>
+    <refname>sd_event_source_get_description</refname>
+
+    <refpurpose>Set or retrieve descriptive names of event sources</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcsynopsisinfo>#include &lt;elogind/sd-event.h&gt;</funcsynopsisinfo>
+
+      <funcprototype>
+        <funcdef>int <function>sd_event_source_set_description</function></funcdef>
+        <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
+        <paramdef>const char *<parameter>description</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_event_source_get_description</function></funcdef>
+        <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
+        <paramdef>const char **<parameter>description</parameter></paramdef>
+      </funcprototype>
+
+    </funcsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para><function>sd_event_source_set_description()</function> may
+    be used to set an arbitrary descriptive name for the event source
+    object specified as <parameter>source</parameter>. This name will
+    be used in debugging messages generated by
+    <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    for this event source, and may be queried using
+    <function>sd_event_source_get_description()</function> for
+    debugging purposes. The <parameter>description</parameter> parameter shall
+    point to a <constant>NUL</constant>-terminated string or be
+    <constant>NULL</constant>. In the latter case, the descriptive
+    name will be unset. The string is copied internally, hence the
+    <parameter>description</parameter> argument is not referenced
+    after the function returns.</para>
+
+    <para><function>sd_event_source_get_description()</function> may
+    be used to query the current descriptive name assigned to the
+    event source object <parameter>source</parameter>. It returns a
+    pointer to the current name in <parameter>description</parameter>,
+    stored in memory internal to the event source. The memory is
+    invalidated when the event source is destroyed or the descriptive
+    name is changed.</para>
+
+    <para>Event source objects generally have no description set when
+    they are created, except for UNIX signal event sources created
+    with
+    <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+    whose descriptive name is initialized to the signal's C constant
+    name (e.g. <literal>SIGINT</literal> or
+    <literal>SIGTERM</literal>).</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Return Value</title>
+
+    <para>On success, <function>sd_event_source_set_description()</function> and
+    <function>sd_event_source_get_description()</function> return a
+    non-negative integer. 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 or the <parameter>description</parameter> argument for
+        <function>sd_event_source_get_description()</function> is
+        <constant>NULL</constant>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><constant>-ENOMEM</constant></term>
+
+        <listitem><para>Not enough memory to copy the
+        name.</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>-ENXIO</constant></term>
+
+        <listitem><para>No name was set for the event
+        source.</para></listitem>
+      </varlistentry>
+
+    </variablelist>
+  </refsect1>
+
+  <xi:include href="libelogind-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_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+
+</refentry>