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1 <?xml version='1.0'?> <!--*-nxml-*-->
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 <!--
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8   Copyright 2010 Lennart Poettering
9
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22 -->
23
24 <refentry id="sd-daemon"
25   xmlns:xi="http://www.w3.org/2001/XInclude">
26
27   <refentryinfo>
28     <title>sd-daemon</title>
29     <productname>systemd</productname>
30
31     <authorgroup>
32       <author>
33         <contrib>Developer</contrib>
34         <firstname>Lennart</firstname>
35         <surname>Poettering</surname>
36         <email>lennart@poettering.net</email>
37       </author>
38     </authorgroup>
39   </refentryinfo>
40
41   <refmeta>
42     <refentrytitle>sd-daemon</refentrytitle>
43     <manvolnum>3</manvolnum>
44   </refmeta>
45
46   <refnamediv>
47     <refname>sd-daemon</refname>
48     <refname>SD_EMERG</refname>
49     <refname>SD_ALERT</refname>
50     <refname>SD_CRIT</refname>
51     <refname>SD_ERR</refname>
52     <refname>SD_WARNING</refname>
53     <refname>SD_NOTICE</refname>
54     <refname>SD_INFO</refname>
55     <refname>SD_DEBUG</refname>
56     <refpurpose>APIs for
57     new-style daemons</refpurpose>
58   </refnamediv>
59
60   <refsynopsisdiv>
61     <funcsynopsis>
62       <funcsynopsisinfo>#include &lt;systemd/sd-daemon.h&gt;</funcsynopsisinfo>
63     </funcsynopsis>
64
65     <cmdsynopsis>
66       <command>pkg-config --cflags --libs libsystemd</command>
67     </cmdsynopsis>
68
69   </refsynopsisdiv>
70
71   <refsect1>
72     <title>Description</title>
73
74     <para><filename>sd-daemon.h</filename> provide APIs for new-style
75     daemons, as implemented by the
76     <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
77     init system.</para>
78
79     <para>See
80     <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
81     <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
82     <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
83     <citerefentry><refentrytitle>sd_is_fifo</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
84     <citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
85     for more information about the functions implemented. In addition
86     to these functions, a couple of logging prefixes are defined as
87     macros:</para>
88
89     <programlisting>#define SD_EMERG   "&lt;0&gt;"  /* system is unusable */
90 #define SD_ALERT   "&lt;1&gt;"  /* action must be taken immediately */
91 #define SD_CRIT    "&lt;2&gt;"  /* critical conditions */
92 #define SD_ERR     "&lt;3&gt;"  /* error conditions */
93 #define SD_WARNING "&lt;4&gt;"  /* warning conditions */
94 #define SD_NOTICE  "&lt;5&gt;"  /* normal but significant condition */
95 #define SD_INFO    "&lt;6&gt;"  /* informational */
96 #define SD_DEBUG   "&lt;7&gt;"  /* debug-level messages */</programlisting>
97
98     <para>These prefixes are intended to be used in conjunction with
99     stderr-based logging as implemented by systemd. If a systemd
100     service definition file is configured with
101     <varname>StandardError=journal</varname>,
102     <varname>StandardError=syslog</varname> or
103     <varname>StandardError=kmsg</varname>, these prefixes can be used
104     to encode a log level in lines printed. This is similar to the
105     kernel <function>printk()</function>-style logging. See
106     <citerefentry><refentrytitle>klogctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
107     for more information.</para>
108
109     <para>The log levels are identical to
110     <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>'s
111     log level system. To use these prefixes simply prefix every line
112     with one of these strings. A line that is not prefixed will be
113     logged at the default log level SD_INFO.</para>
114
115     <example>
116       <title>Hello World</title>
117
118       <para>A daemon may log with the log level NOTICE by issuing this
119       call:</para>
120
121       <programlisting>fprintf(stderr, SD_NOTICE "Hello World!\n");</programlisting>
122     </example>
123   </refsect1>
124
125   <xi:include href="libsystemd-pkgconfig.xml" />
126
127   <refsect1>
128     <title>See Also</title>
129     <para>
130       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
131       <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
132       <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
133       <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
134       <citerefentry><refentrytitle>sd_is_fifo</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
135       <citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
136       <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
137       <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
138       <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
139       <citerefentry project='man-pages'><refentrytitle>fprintf</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
140       <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
141     </para>
142   </refsect1>
143
144 </refentry>