1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="sd_event_source_set_description" xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_event_source_set_description</title>
<productname>systemd</productname>
</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 <systemd/sd-event.h></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>ret</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>ret</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>
<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 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, library or module instance.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENXIO</constant></term>
<listitem><para>No name was set for the event source.</para></listitem>
</varlistentry>
</variablelist>
</refsect2>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<refsect1>
<title>History</title>
<para><function>sd_event_source_set_description()</function> and
<function>sd_event_source_get_description()</function> were added in version 229.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para><simplelist type="inline">
<member><citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_inotify</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
</simplelist></para>
</refsect1>
</refentry>
|
