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
|
<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
SPDX-License-Identifier: LGPL-2.1+
Copyright 2010 Lennart Poettering
-->
<refentry id="sd-daemon"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd-daemon</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd-daemon</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd-daemon</refname>
<refname>SD_EMERG</refname>
<refname>SD_ALERT</refname>
<refname>SD_CRIT</refname>
<refname>SD_ERR</refname>
<refname>SD_WARNING</refname>
<refname>SD_NOTICE</refname>
<refname>SD_INFO</refname>
<refname>SD_DEBUG</refname>
<refpurpose>APIs for
new-style daemons</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <systemd/sd-daemon.h></funcsynopsisinfo>
</funcsynopsis>
<cmdsynopsis>
<command>pkg-config --cflags --libs libsystemd</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><filename>sd-daemon.h</filename> provides APIs for new-style
daemons, as implemented by the
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
service manager.</para>
<para>See
<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_is_fifo</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for more information about the functions implemented. In addition
to these functions, a couple of logging prefixes are defined as
macros:</para>
<programlisting>#define SD_EMERG "<0>" /* system is unusable */
#define SD_ALERT "<1>" /* action must be taken immediately */
#define SD_CRIT "<2>" /* critical conditions */
#define SD_ERR "<3>" /* error conditions */
#define SD_WARNING "<4>" /* warning conditions */
#define SD_NOTICE "<5>" /* normal but significant condition */
#define SD_INFO "<6>" /* informational */
#define SD_DEBUG "<7>" /* debug-level messages */</programlisting>
<para>These prefixes are intended to be used in conjunction with
stderr-based logging as implemented by systemd. If a systemd
service definition file is configured with
<varname>StandardError=journal</varname>,
<varname>StandardError=syslog</varname> or
<varname>StandardError=kmsg</varname>, these prefixes can be used
to encode a log level in lines printed. This is similar to the
kernel <function>printk()</function>-style logging. See
<citerefentry><refentrytitle>klogctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
for more information.</para>
<para>The log levels are identical to
<citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>'s
log level system. To use these prefixes simply prefix every line
with one of these strings. A line that is not prefixed will be
logged at the default log level SD_INFO.</para>
<example>
<title>Hello World</title>
<para>A daemon may log with the log level NOTICE by issuing this
call:</para>
<programlisting>fprintf(stderr, SD_NOTICE "Hello World!\n");</programlisting>
</example>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_is_fifo</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>fprintf</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|
