]>
Commit | Line | Data |
---|---|---|
514094f9 | 1 | <?xml version='1.0'?> |
3a54a157 ZJS |
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+ --> |
dc83f27a LP |
5 | |
6 | <refentry id="sd_event_now" xmlns:xi="http://www.w3.org/2001/XInclude"> | |
7 | ||
8 | <refentryinfo> | |
9 | <title>sd_event_now</title> | |
10 | <productname>systemd</productname> | |
dc83f27a LP |
11 | </refentryinfo> |
12 | ||
13 | <refmeta> | |
14 | <refentrytitle>sd_event_now</refentrytitle> | |
15 | <manvolnum>3</manvolnum> | |
16 | </refmeta> | |
17 | ||
18 | <refnamediv> | |
19 | <refname>sd_event_now</refname> | |
20 | ||
21 | <refpurpose>Retrieve current event loop iteration timestamp</refpurpose> | |
22 | </refnamediv> | |
23 | ||
24 | <refsynopsisdiv> | |
25 | <funcsynopsis> | |
26 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
27 | ||
28 | <funcprototype> | |
29 | <funcdef>int <function>sd_event_now</function></funcdef> | |
30 | <paramdef>sd_event *<parameter>event</parameter></paramdef> | |
31 | <paramdef>clockid_t <parameter>clock</parameter></paramdef> | |
32 | <paramdef>uint64_t *<parameter>usec</parameter></paramdef> | |
33 | </funcprototype> | |
34 | ||
35 | </funcsynopsis> | |
36 | </refsynopsisdiv> | |
37 | ||
38 | <refsect1> | |
39 | <title>Description</title> | |
40 | ||
f23e83b1 ZJS |
41 | <para><function>sd_event_now()</function> returns the time when |
42 | the most recent event loop iteration began. A timestamp | |
43 | is taken right after returning from the event sleep, and before | |
dc83f27a | 44 | dispatching any event sources. The <parameter>event</parameter> |
f23e83b1 | 45 | parameter specifies the event loop object to retrieve the timestamp |
dc83f27a LP |
46 | from. The <parameter>clock</parameter> parameter specifies the clock to |
47 | retrieve the timestamp for, and is one of | |
f23e83b1 | 48 | <constant>CLOCK_REALTIME</constant> (or equivalently |
dc83f27a | 49 | <constant>CLOCK_REALTIME_ALARM</constant>), |
f23e83b1 ZJS |
50 | <constant>CLOCK_MONOTONIC</constant>, or |
51 | <constant>CLOCK_BOOTTIME</constant> (or equivalently | |
52 | <constant>CLOCK_BOOTTIME_ALARM</constant>), see | |
53 | <citerefentry project='man-pages'><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
dc83f27a LP |
54 | for more information on the various clocks. The retrieved |
55 | timestamp is stored in the <parameter>usec</parameter> parameter, | |
56 | in µs since the clock's epoch. If this function is invoked before | |
f23e83b1 | 57 | the first event loop iteration, the current time is returned, as |
dc83f27a LP |
58 | reported by <function>clock_gettime()</function>. To distinguish |
59 | this case from a regular invocation the return value will be | |
f23e83b1 ZJS |
60 | positive, and zero when the returned timestamp refers to an actual |
61 | event loop iteration.</para> | |
dc83f27a LP |
62 | </refsect1> |
63 | ||
64 | <refsect1> | |
65 | <title>Return Value</title> | |
66 | ||
b1de39de ZJS |
67 | <para>If the first event loop iteration has not run yet <function>sd_event_now()</function> writes |
68 | current time to <parameter>usec</parameter> and returns a positive return value. Otherwise, it will | |
69 | write the requested timestamp to <parameter>usec</parameter> and return 0. On failure, the call returns a | |
70 | negative errno-style error code.</para> | |
dc83f27a | 71 | |
b1de39de ZJS |
72 | <refsect2> |
73 | <title>Errors</title> | |
dc83f27a | 74 | |
b1de39de | 75 | <para>Returned values may indicate the following problems:</para> |
dc83f27a | 76 | |
b1de39de ZJS |
77 | <variablelist> |
78 | <varlistentry> | |
79 | <term><constant>-EINVAL</constant></term> | |
dc83f27a | 80 | |
b1de39de | 81 | <listitem><para>An invalid parameter was passed.</para></listitem> |
dc83f27a | 82 | |
b1de39de | 83 | </varlistentry> |
dc83f27a | 84 | |
b1de39de ZJS |
85 | <varlistentry> |
86 | <term><constant>-EOPNOTSUPP</constant></term> | |
2c86ba5a | 87 | |
b1de39de ZJS |
88 | <listitem><para>Unsupported clock type.</para></listitem> |
89 | </varlistentry> | |
2c86ba5a | 90 | |
b1de39de ZJS |
91 | <varlistentry> |
92 | <term><constant>-ECHILD</constant></term> | |
dc83f27a | 93 | |
b1de39de ZJS |
94 | <listitem><para>The event loop object was created in a different process.</para></listitem> |
95 | </varlistentry> | |
96 | </variablelist> | |
97 | </refsect2> | |
dc83f27a LP |
98 | </refsect1> |
99 | ||
100 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
101 | ||
102 | <refsect1> | |
103 | <title>See Also</title> | |
104 | ||
105 | <para> | |
106 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
107 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
108 | <citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
109 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
110 | <citerefentry project='man-pages'><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
111 | </para> | |
112 | </refsect1> | |
113 | ||
114 | </refentry> |