]>
Commit | Line | Data |
---|---|---|
dc83f27a LP |
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 2015 Lennart Poettering | |
dc83f27a LP |
11 | --> |
12 | ||
13 | <refentry id="sd_event_source_get_pending" xmlns:xi="http://www.w3.org/2001/XInclude"> | |
14 | ||
15 | <refentryinfo> | |
16 | <title>sd_event_source_get_pending</title> | |
17 | <productname>systemd</productname> | |
18 | ||
19 | <authorgroup> | |
20 | <author> | |
21 | <contrib>Developer</contrib> | |
22 | <firstname>Lennart</firstname> | |
23 | <surname>Poettering</surname> | |
24 | <email>lennart@poettering.net</email> | |
25 | </author> | |
26 | </authorgroup> | |
27 | </refentryinfo> | |
28 | ||
29 | <refmeta> | |
30 | <refentrytitle>sd_event_source_get_pending</refentrytitle> | |
31 | <manvolnum>3</manvolnum> | |
32 | </refmeta> | |
33 | ||
34 | <refnamediv> | |
35 | <refname>sd_event_source_get_pending</refname> | |
36 | ||
37 | <refpurpose>Determine pending state of event sources</refpurpose> | |
38 | </refnamediv> | |
39 | ||
40 | <refsynopsisdiv> | |
41 | <funcsynopsis> | |
42 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
43 | ||
44 | <funcprototype> | |
45 | <funcdef>int <function>sd_event_source_get_pending</function></funcdef> | |
46 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
47 | </funcprototype> | |
48 | ||
49 | </funcsynopsis> | |
50 | </refsynopsisdiv> | |
51 | ||
52 | <refsect1> | |
53 | <title>Description</title> | |
54 | ||
55 | <para><function>sd_event_source_get_pending()</function> may be | |
56 | used to determine whether the event source object specified as | |
57 | <parameter>source</parameter> has seen events but has not been | |
58 | dispatched yet (and thus is marked "pending").</para> | |
59 | ||
60 | <para>Event source objects initially are not marked pending, when | |
61 | they are created with calls such as | |
62 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
63 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
64 | with the exception of those created with | |
65 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
66 | which are immediately marked pending, and | |
67 | <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
68 | for which the "pending" concept is not defined. For details see | |
69 | the respective manual pages.</para> | |
70 | ||
71 | <para>In each event loop iteration one event source of those | |
72 | marked pending is dispatched, in the order defined by the event | |
73 | source priority, as set with | |
74 | <citerefentry><refentrytitle>sd_event_source_set_priority</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> | |
75 | ||
76 | <para>For I/O event sources, as created with | |
77 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
78 | the call | |
a3972469 | 79 | <citerefentry><refentrytitle>sd_event_source_get_io_revents</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
dc83f27a LP |
80 | may be used to query the type of event pending in more |
81 | detail.</para> | |
82 | ||
83 | </refsect1> | |
84 | ||
85 | <refsect1> | |
86 | <title>Return Value</title> | |
87 | ||
88 | <para>On success, | |
89 | <function>sd_event_source_get_pending()</function> returns an | |
90 | integer greater than zero when the event source is marked pending, | |
91 | and zero when the event source is not marked pending. On failure, | |
92 | it returns a negative errno-style error code.</para> | |
93 | </refsect1> | |
94 | ||
95 | <refsect1> | |
96 | <title>Errors</title> | |
97 | ||
98 | <para>Returned errors may indicate the following problems:</para> | |
99 | ||
100 | <variablelist> | |
101 | <varlistentry> | |
102 | <term><constant>-EINVAL</constant></term> | |
103 | ||
104 | <listitem><para><parameter>source</parameter> is not a valid | |
105 | pointer to an <structname>sd_event_source</structname> | |
106 | object.</para></listitem> | |
107 | </varlistentry> | |
108 | ||
109 | <varlistentry> | |
110 | <term><constant>-EDOM</constant></term> | |
111 | ||
112 | <listitem><para><parameter>source</parameter> refers to an | |
113 | event source object created with | |
114 | <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem> | |
115 | </varlistentry> | |
116 | ||
117 | <varlistentry> | |
118 | <term><constant>-ENOMEM</constant></term> | |
119 | ||
120 | <listitem><para>Not enough memory.</para></listitem> | |
121 | </varlistentry> | |
122 | ||
123 | <varlistentry> | |
124 | <term><constant>-ESTALE</constant></term> | |
125 | ||
126 | <listitem><para>The event loop is already terminated.</para></listitem> | |
127 | ||
128 | </varlistentry> | |
129 | ||
130 | <varlistentry> | |
131 | <term><constant>-ECHILD</constant></term> | |
132 | ||
133 | <listitem><para>The event loop has been created in a different process.</para></listitem> | |
134 | ||
135 | </varlistentry> | |
136 | ||
137 | </variablelist> | |
138 | </refsect1> | |
139 | ||
140 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
141 | ||
142 | <refsect1> | |
143 | <title>See Also</title> | |
144 | ||
145 | <para> | |
146 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
147 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
148 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
149 | <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
150 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
151 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
152 | <citerefentry><refentrytitle>sd_event_source_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
153 | </para> | |
154 | </refsect1> | |
155 | ||
156 | </refentry> |