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514094f9 | 1 | <?xml version='1.0'?> |
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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 | 6 | SPDX-License-Identifier: LGPL-2.1+ |
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7 | --> |
8 | ||
9 | <refentry id="sd_event_source_set_description" xmlns:xi="http://www.w3.org/2001/XInclude"> | |
10 | ||
11 | <refentryinfo> | |
12 | <title>sd_event_source_set_description</title> | |
13 | <productname>systemd</productname> | |
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14 | </refentryinfo> |
15 | ||
16 | <refmeta> | |
17 | <refentrytitle>sd_event_source_set_description</refentrytitle> | |
18 | <manvolnum>3</manvolnum> | |
19 | </refmeta> | |
20 | ||
21 | <refnamediv> | |
22 | <refname>sd_event_source_set_description</refname> | |
23 | <refname>sd_event_source_get_description</refname> | |
24 | ||
25 | <refpurpose>Set or retrieve descriptive names of event sources</refpurpose> | |
26 | </refnamediv> | |
27 | ||
28 | <refsynopsisdiv> | |
29 | <funcsynopsis> | |
30 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
31 | ||
32 | <funcprototype> | |
33 | <funcdef>int <function>sd_event_source_set_description</function></funcdef> | |
34 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
35 | <paramdef>const char *<parameter>description</parameter></paramdef> | |
36 | </funcprototype> | |
37 | ||
38 | <funcprototype> | |
39 | <funcdef>int <function>sd_event_source_get_description</function></funcdef> | |
40 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
41 | <paramdef>const char **<parameter>description</parameter></paramdef> | |
42 | </funcprototype> | |
43 | ||
44 | </funcsynopsis> | |
45 | </refsynopsisdiv> | |
46 | ||
47 | <refsect1> | |
48 | <title>Description</title> | |
49 | ||
50 | <para><function>sd_event_source_set_description()</function> may | |
51 | be used to set an arbitrary descriptive name for the event source | |
52 | object specified as <parameter>source</parameter>. This name will | |
53 | be used in debugging messages generated by | |
54 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
55 | for this event source, and may be queried using | |
56 | <function>sd_event_source_get_description()</function> for | |
57 | debugging purposes. The <parameter>description</parameter> parameter shall | |
58 | point to a <constant>NUL</constant>-terminated string or be | |
59 | <constant>NULL</constant>. In the latter case, the descriptive | |
60 | name will be unset. The string is copied internally, hence the | |
61 | <parameter>description</parameter> argument is not referenced | |
62 | after the function returns.</para> | |
63 | ||
64 | <para><function>sd_event_source_get_description()</function> may | |
65 | be used to query the current descriptive name assigned to the | |
66 | event source object <parameter>source</parameter>. It returns a | |
67 | pointer to the current name in <parameter>description</parameter>, | |
68 | stored in memory internal to the event source. The memory is | |
69 | invalidated when the event source is destroyed or the descriptive | |
70 | name is changed.</para> | |
71 | ||
72 | <para>Event source objects generally have no description set when | |
73 | they are created, except for UNIX signal event sources created | |
74 | with | |
75 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
76 | whose descriptive name is initialized to the signal's C constant | |
77 | name (e.g. <literal>SIGINT</literal> or | |
78 | <literal>SIGTERM</literal>).</para> | |
79 | </refsect1> | |
80 | ||
81 | <refsect1> | |
82 | <title>Return Value</title> | |
83 | ||
84 | <para>On success, <function>sd_event_source_set_description()</function> and | |
85 | <function>sd_event_source_get_description()</function> return a | |
86 | non-negative integer. On failure, they return a negative | |
87 | errno-style error code.</para> | |
88 | </refsect1> | |
89 | ||
90 | <refsect1> | |
91 | <title>Errors</title> | |
92 | ||
93 | <para>Returned errors may indicate the following problems:</para> | |
94 | ||
95 | <variablelist> | |
96 | <varlistentry> | |
97 | <term><constant>-EINVAL</constant></term> | |
98 | ||
99 | <listitem><para><parameter>source</parameter> is not a valid | |
100 | pointer to an <structname>sd_event_source</structname> | |
101 | object or the <parameter>description</parameter> argument for | |
102 | <function>sd_event_source_get_description()</function> is | |
103 | <constant>NULL</constant>.</para></listitem> | |
104 | </varlistentry> | |
105 | ||
106 | <varlistentry> | |
107 | <term><constant>-ENOMEM</constant></term> | |
108 | ||
109 | <listitem><para>Not enough memory to copy the | |
110 | name.</para></listitem> | |
111 | </varlistentry> | |
112 | ||
113 | <varlistentry> | |
114 | <term><constant>-ECHILD</constant></term> | |
115 | ||
116 | <listitem><para>The event loop has been created in a different process.</para></listitem> | |
117 | ||
118 | </varlistentry> | |
119 | ||
120 | <varlistentry> | |
121 | <term><constant>-ENXIO</constant></term> | |
122 | ||
123 | <listitem><para>No name was set for the event | |
124 | source.</para></listitem> | |
125 | </varlistentry> | |
126 | ||
127 | </variablelist> | |
128 | </refsect1> | |
129 | ||
130 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
131 | ||
132 | <refsect1> | |
133 | <title>See Also</title> | |
134 | ||
135 | <para> | |
136 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
137 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
138 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
139 | <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
140 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
141 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
142 | <citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
143 | </para> | |
144 | </refsect1> | |
145 | ||
146 | </refentry> |