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514094f9 | 1 | <?xml version='1.0'?> |
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2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
0307f791 | 4 | <!-- SPDX-License-Identifier: LGPL-2.1+ --> |
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5 | |
6 | <refentry id="sd_event_source_set_description" xmlns:xi="http://www.w3.org/2001/XInclude"> | |
7 | ||
8 | <refentryinfo> | |
9 | <title>sd_event_source_set_description</title> | |
10 | <productname>systemd</productname> | |
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11 | </refentryinfo> |
12 | ||
13 | <refmeta> | |
14 | <refentrytitle>sd_event_source_set_description</refentrytitle> | |
15 | <manvolnum>3</manvolnum> | |
16 | </refmeta> | |
17 | ||
18 | <refnamediv> | |
19 | <refname>sd_event_source_set_description</refname> | |
20 | <refname>sd_event_source_get_description</refname> | |
21 | ||
22 | <refpurpose>Set or retrieve descriptive names of event sources</refpurpose> | |
23 | </refnamediv> | |
24 | ||
25 | <refsynopsisdiv> | |
26 | <funcsynopsis> | |
27 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
28 | ||
29 | <funcprototype> | |
30 | <funcdef>int <function>sd_event_source_set_description</function></funcdef> | |
31 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
32 | <paramdef>const char *<parameter>description</parameter></paramdef> | |
33 | </funcprototype> | |
34 | ||
35 | <funcprototype> | |
36 | <funcdef>int <function>sd_event_source_get_description</function></funcdef> | |
37 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
38 | <paramdef>const char **<parameter>description</parameter></paramdef> | |
39 | </funcprototype> | |
40 | ||
41 | </funcsynopsis> | |
42 | </refsynopsisdiv> | |
43 | ||
44 | <refsect1> | |
45 | <title>Description</title> | |
46 | ||
47 | <para><function>sd_event_source_set_description()</function> may | |
48 | be used to set an arbitrary descriptive name for the event source | |
49 | object specified as <parameter>source</parameter>. This name will | |
50 | be used in debugging messages generated by | |
51 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
52 | for this event source, and may be queried using | |
53 | <function>sd_event_source_get_description()</function> for | |
54 | debugging purposes. The <parameter>description</parameter> parameter shall | |
55 | point to a <constant>NUL</constant>-terminated string or be | |
56 | <constant>NULL</constant>. In the latter case, the descriptive | |
57 | name will be unset. The string is copied internally, hence the | |
58 | <parameter>description</parameter> argument is not referenced | |
59 | after the function returns.</para> | |
60 | ||
61 | <para><function>sd_event_source_get_description()</function> may | |
62 | be used to query the current descriptive name assigned to the | |
63 | event source object <parameter>source</parameter>. It returns a | |
64 | pointer to the current name in <parameter>description</parameter>, | |
65 | stored in memory internal to the event source. The memory is | |
66 | invalidated when the event source is destroyed or the descriptive | |
67 | name is changed.</para> | |
68 | ||
69 | <para>Event source objects generally have no description set when | |
70 | they are created, except for UNIX signal event sources created | |
71 | with | |
72 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
73 | whose descriptive name is initialized to the signal's C constant | |
74 | name (e.g. <literal>SIGINT</literal> or | |
75 | <literal>SIGTERM</literal>).</para> | |
76 | </refsect1> | |
77 | ||
78 | <refsect1> | |
79 | <title>Return Value</title> | |
80 | ||
81 | <para>On success, <function>sd_event_source_set_description()</function> and | |
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82 | <function>sd_event_source_get_description()</function> return a non-negative integer. On failure, they |
83 | return a negative errno-style error code.</para> | |
dc83f27a | 84 | |
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85 | <refsect2> |
86 | <title>Errors</title> | |
dc83f27a | 87 | |
b1de39de | 88 | <para>Returned errors may indicate the following problems:</para> |
dc83f27a | 89 | |
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90 | <variablelist> |
91 | <varlistentry> | |
92 | <term><constant>-EINVAL</constant></term> | |
dc83f27a | 93 | |
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94 | <listitem><para><parameter>source</parameter> is not a valid pointer to an |
95 | <structname>sd_event_source</structname> object or the <parameter>description</parameter> argument | |
96 | for <function>sd_event_source_get_description()</function> is <constant>NULL</constant>. | |
97 | </para></listitem> | |
98 | </varlistentry> | |
dc83f27a | 99 | |
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100 | <varlistentry> |
101 | <term><constant>-ENOMEM</constant></term> | |
dc83f27a | 102 | |
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103 | <listitem><para>Not enough memory to copy the name.</para></listitem> |
104 | </varlistentry> | |
dc83f27a | 105 | |
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106 | <varlistentry> |
107 | <term><constant>-ECHILD</constant></term> | |
dc83f27a | 108 | |
b1de39de | 109 | <listitem><para>The event loop has been created in a different process.</para></listitem> |
dc83f27a | 110 | |
b1de39de | 111 | </varlistentry> |
dc83f27a | 112 | |
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113 | <varlistentry> |
114 | <term><constant>-ENXIO</constant></term> | |
dc83f27a | 115 | |
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116 | <listitem><para>No name was set for the event source.</para></listitem> |
117 | </varlistentry> | |
dc83f27a | 118 | |
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119 | </variablelist> |
120 | </refsect2> | |
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121 | </refsect1> |
122 | ||
123 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
124 | ||
125 | <refsect1> | |
126 | <title>See Also</title> | |
127 | ||
128 | <para> | |
129 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
130 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
131 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
dc83f27a | 132 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
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133 | <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
134 | <citerefentry><refentrytitle>sd_event_add_inotify</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
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135 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
136 | <citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
137 | </para> | |
138 | </refsect1> | |
139 | ||
140 | </refentry> |