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1 | <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> |
2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
4 | ||
5 | <!-- | |
572eb058 ZJS |
6 | SPDX-License-Identifier: LGPL-2.1+ |
7 | ||
dc83f27a LP |
8 | This file is part of systemd. |
9 | ||
10 | Copyright 2014 Zbigniew Jędrzejewski-Szmek | |
dc83f27a LP |
11 | --> |
12 | ||
13 | <refentry id="sd_event_source_set_description" xmlns:xi="http://www.w3.org/2001/XInclude"> | |
14 | ||
15 | <refentryinfo> | |
16 | <title>sd_event_source_set_description</title> | |
17 | <productname>systemd</productname> | |
18 | ||
19 | <authorgroup> | |
20 | <author> | |
21 | <contrib>More text</contrib> | |
22 | <firstname>Zbigniew</firstname> | |
23 | <surname>Jędrzejewski-Szmek</surname> | |
24 | <email>zbyszek@in.waw.pl</email> | |
25 | </author> | |
26 | </authorgroup> | |
27 | </refentryinfo> | |
28 | ||
29 | <refmeta> | |
30 | <refentrytitle>sd_event_source_set_description</refentrytitle> | |
31 | <manvolnum>3</manvolnum> | |
32 | </refmeta> | |
33 | ||
34 | <refnamediv> | |
35 | <refname>sd_event_source_set_description</refname> | |
36 | <refname>sd_event_source_get_description</refname> | |
37 | ||
38 | <refpurpose>Set or retrieve descriptive names of event sources</refpurpose> | |
39 | </refnamediv> | |
40 | ||
41 | <refsynopsisdiv> | |
42 | <funcsynopsis> | |
43 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
44 | ||
45 | <funcprototype> | |
46 | <funcdef>int <function>sd_event_source_set_description</function></funcdef> | |
47 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
48 | <paramdef>const char *<parameter>description</parameter></paramdef> | |
49 | </funcprototype> | |
50 | ||
51 | <funcprototype> | |
52 | <funcdef>int <function>sd_event_source_get_description</function></funcdef> | |
53 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
54 | <paramdef>const char **<parameter>description</parameter></paramdef> | |
55 | </funcprototype> | |
56 | ||
57 | </funcsynopsis> | |
58 | </refsynopsisdiv> | |
59 | ||
60 | <refsect1> | |
61 | <title>Description</title> | |
62 | ||
63 | <para><function>sd_event_source_set_description()</function> may | |
64 | be used to set an arbitrary descriptive name for the event source | |
65 | object specified as <parameter>source</parameter>. This name will | |
66 | be used in debugging messages generated by | |
67 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
68 | for this event source, and may be queried using | |
69 | <function>sd_event_source_get_description()</function> for | |
70 | debugging purposes. The <parameter>description</parameter> parameter shall | |
71 | point to a <constant>NUL</constant>-terminated string or be | |
72 | <constant>NULL</constant>. In the latter case, the descriptive | |
73 | name will be unset. The string is copied internally, hence the | |
74 | <parameter>description</parameter> argument is not referenced | |
75 | after the function returns.</para> | |
76 | ||
77 | <para><function>sd_event_source_get_description()</function> may | |
78 | be used to query the current descriptive name assigned to the | |
79 | event source object <parameter>source</parameter>. It returns a | |
80 | pointer to the current name in <parameter>description</parameter>, | |
81 | stored in memory internal to the event source. The memory is | |
82 | invalidated when the event source is destroyed or the descriptive | |
83 | name is changed.</para> | |
84 | ||
85 | <para>Event source objects generally have no description set when | |
86 | they are created, except for UNIX signal event sources created | |
87 | with | |
88 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
89 | whose descriptive name is initialized to the signal's C constant | |
90 | name (e.g. <literal>SIGINT</literal> or | |
91 | <literal>SIGTERM</literal>).</para> | |
92 | </refsect1> | |
93 | ||
94 | <refsect1> | |
95 | <title>Return Value</title> | |
96 | ||
97 | <para>On success, <function>sd_event_source_set_description()</function> and | |
98 | <function>sd_event_source_get_description()</function> return a | |
99 | non-negative integer. On failure, they return a negative | |
100 | errno-style error code.</para> | |
101 | </refsect1> | |
102 | ||
103 | <refsect1> | |
104 | <title>Errors</title> | |
105 | ||
106 | <para>Returned errors may indicate the following problems:</para> | |
107 | ||
108 | <variablelist> | |
109 | <varlistentry> | |
110 | <term><constant>-EINVAL</constant></term> | |
111 | ||
112 | <listitem><para><parameter>source</parameter> is not a valid | |
113 | pointer to an <structname>sd_event_source</structname> | |
114 | object or the <parameter>description</parameter> argument for | |
115 | <function>sd_event_source_get_description()</function> is | |
116 | <constant>NULL</constant>.</para></listitem> | |
117 | </varlistentry> | |
118 | ||
119 | <varlistentry> | |
120 | <term><constant>-ENOMEM</constant></term> | |
121 | ||
122 | <listitem><para>Not enough memory to copy the | |
123 | name.</para></listitem> | |
124 | </varlistentry> | |
125 | ||
126 | <varlistentry> | |
127 | <term><constant>-ECHILD</constant></term> | |
128 | ||
129 | <listitem><para>The event loop has been created in a different process.</para></listitem> | |
130 | ||
131 | </varlistentry> | |
132 | ||
133 | <varlistentry> | |
134 | <term><constant>-ENXIO</constant></term> | |
135 | ||
136 | <listitem><para>No name was set for the event | |
137 | source.</para></listitem> | |
138 | </varlistentry> | |
139 | ||
140 | </variablelist> | |
141 | </refsect1> | |
142 | ||
143 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
144 | ||
145 | <refsect1> | |
146 | <title>See Also</title> | |
147 | ||
148 | <para> | |
149 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
150 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
151 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
152 | <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
153 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
154 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
155 | <citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
156 | </para> | |
157 | </refsect1> | |
158 | ||
159 | </refentry> |