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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
- "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
-<!ENTITY % entities SYSTEM "custom-entities.ent" >
-%entities;
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+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
+ SPDX-License-Identifier: LGPL-2.1+
+
This file is part of systemd.
Copyright 2012 Lennart Poettering
<funcdef>int <function>sd_journal_print</function></funcdef>
<paramdef>int <parameter>priority</parameter></paramdef>
<paramdef>const char *<parameter>format</parameter></paramdef>
- <paramdef>...</paramdef>
+ <paramdef>…</paramdef>
</funcprototype>
<funcprototype>
<funcprototype>
<funcdef>int <function>sd_journal_send</function></funcdef>
<paramdef>const char *<parameter>format</parameter></paramdef>
- <paramdef>...</paramdef>
+ <paramdef>…</paramdef>
</funcprototype>
<funcprototype>
<refsect1>
<title>Description</title>
- <para><function>sd_journal_print()</function> may be used to
- submit simple, plain text log entries to the system journal. The
- first argument is a priority value. This is followed by a format
- string and its parameters, similar to
- <citerefentry project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- or
+ <para><function>sd_journal_print()</function> may be used to submit simple, plain text log entries to the system
+ journal. The first argument is a priority value. This is followed by a format string and its parameters, similar to
+ <citerefentry project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry> or
<citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
- The priority value is one of
- <constant>LOG_EMERG</constant>,
- <constant>LOG_ALERT</constant>,
- <constant>LOG_CRIT</constant>,
- <constant>LOG_ERR</constant>,
- <constant>LOG_WARNING</constant>,
- <constant>LOG_NOTICE</constant>,
- <constant>LOG_INFO</constant>,
- <constant>LOG_DEBUG</constant>, as defined in
- <filename>syslog.h</filename>, see
- <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for details. It is recommended to use this call to submit log
- messages in the application locale or system locale and in UTF-8
- format, but no such restrictions are enforced.</para>
+ The priority value is one of <constant>LOG_EMERG</constant>, <constant>LOG_ALERT</constant>,
+ <constant>LOG_CRIT</constant>, <constant>LOG_ERR</constant>, <constant>LOG_WARNING</constant>,
+ <constant>LOG_NOTICE</constant>, <constant>LOG_INFO</constant>, <constant>LOG_DEBUG</constant>, as defined in
+ <filename>syslog.h</filename>, see <citerefentry
+ project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> for details. It is
+ recommended to use this call to submit log messages in the application locale or system locale and in UTF-8 format,
+ but no such restrictions are enforced. Note that log messages written using this function are generally not
+ expected to end in a new-line character. However, as all trailing whitespace (including spaces, new-lines,
+ tabulators and carriage returns) are automatically stripped from the logged string, it is acceptable to specify one
+ (or more). Empty lines (after trailing whitespace removal) are suppressed. On non-empty lines, leading whitespace
+ (as well as inner whitespace) is left unmodified. </para>
<para><function>sd_journal_printv()</function> is similar to
<function>sd_journal_print()</function> but takes a variable
for more information) instead of the format string. It is
otherwise equivalent in behavior.</para>
- <para><function>sd_journal_send()</function> may be used to submit
- structured log entries to the system journal. It takes a series of
- format strings, each immediately followed by their associated
- parameters, terminated by <constant>NULL</constant>. The strings
- passed should be of the format <literal>VARIABLE=value</literal>.
- The variable name must be in uppercase and consist only of
- characters, numbers and underscores, and may not begin with an
- underscore. (All assignments that do not follow this syntax will
- be ignored.) The value can be of any size and format. It is highly
- recommended to submit text strings formatted in the UTF-8
- character encoding only, and submit binary fields only when
- formatting in UTF-8 strings is not sensible. A number of well
- known fields are defined, see
- <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- for details, but additional application defined fields may be
- used. A variable may be assigned more than one value per
- entry.</para>
-
- <para><function>sd_journal_sendv()</function> is similar to
- <function>sd_journal_send()</function> but takes an array of
- <varname>struct iovec</varname> (as defined in
- <filename>uio.h</filename>, see
- <citerefentry project='man-pages'><refentrytitle>readv</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for details) instead of the format string. Each structure should
- reference one field of the entry to submit. The second argument
- specifies the number of structures in the array.
- <function>sd_journal_sendv()</function> is particularly useful to
- submit binary objects to the journal where that is
- necessary.</para>
+ <para><function>sd_journal_send()</function> may be used to submit structured log entries to the system journal. It
+ takes a series of format strings, each immediately followed by their associated parameters, terminated by
+ <constant>NULL</constant>. The strings passed should be of the format <literal>VARIABLE=value</literal>. The
+ variable name must be in uppercase and consist only of characters, numbers and underscores, and may not begin with
+ an underscore. (All assignments that do not follow this syntax will be ignored.) The value can be of any size and
+ format. It is highly recommended to submit text strings formatted in the UTF-8 character encoding only, and submit
+ binary fields only when formatting in UTF-8 strings is not sensible. A number of well-known fields are defined, see
+ <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
+ details, but additional application defined fields may be used. A variable may be assigned more than one value per
+ entry. If this function is used, trailing whitespace is automatically removed from each formatted field.</para>
+
+ <para><function>sd_journal_sendv()</function> is similar to <function>sd_journal_send()</function> but takes an
+ array of <varname>struct iovec</varname> (as defined in <filename>uio.h</filename>, see <citerefentry
+ project='man-pages'><refentrytitle>readv</refentrytitle><manvolnum>3</manvolnum></citerefentry> for details)
+ instead of the format string. Each structure should reference one field of the entry to submit. The second argument
+ specifies the number of structures in the array. <function>sd_journal_sendv()</function> is particularly useful to
+ submit binary objects to the journal where that is necessary. Note that this function will not strip trailing
+ whitespace of the passed fields, but passes the specified data along unmodified. This is different from both
+ <function>sd_journal_print()</function> and <function>sd_journal_send()</function> described above, which are based
+ on format strings, and do strip trailing whitespace.</para>
<para><function>sd_journal_perror()</function> is a similar to
<citerefentry project='die-net'><refentrytitle>perror</refentrytitle><manvolnum>3</manvolnum></citerefentry>
and writes a message to the journal that consists of the passed
- string, suffixed with ": " and a human readable representation of
+ string, suffixed with ": " and a human-readable representation of
the current error code stored in
<citerefentry project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
If the message string is passed as <constant>NULL</constant> or
<programlisting>sd_journal_print(LOG_INFO, "Hello World, this is PID %lu!", (unsigned long) getpid());
sd_journal_send("MESSAGE=Hello World, this is PID %lu!", (unsigned long) getpid(),
- "PRIORITY=%i", LOG_INFO,
- NULL);</programlisting>
+ "PRIORITY=%i", LOG_INFO,
+ NULL);</programlisting>
<para>Note that these calls implicitly add fields for the source
file, function name and code line where invoked. This is
<refsect1>
<title>Return Value</title>
- <para>The four calls return 0 on success or a negative errno-style
- error code. The
- <citerefentry project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- variable itself is not altered.</para>
+ <para>The five calls return 0 on success or a negative errno-style error code. The <citerefentry
+ project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry> variable itself is
+ not altered.</para>
<para>If
<citerefentry><refentrytitle>systemd-journald</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</refsect1>
<refsect1>
- <title>Async signal safety</title>
- <para><function>sd_journal_sendv()</function> is "async signal
- safe" in the meaning of
- <citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
+ <title>Thread safety</title>
+ <para>All functions listed here are thread-safe and may be called in parallel from multiple threads.</para>
+
+ <para><function>sd_journal_sendv()</function> is "async signal safe" in the meaning of <citerefentry
+ project='man-pages'><refentrytitle>signal-safety</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
</para>
<para><function>sd_journal_print</function>,
<refsect1>
<title>Notes</title>
- <para>The <function>sd_journal_print()</function>,
- <function>sd_journal_printv()</function>,
- <function>sd_journal_send()</function> and
- <function>sd_journal_sendv()</function> interfaces are available
- as a shared library, which can be compiled and linked to with the
- <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- file.</para>
+ <para>The <function>sd_journal_print()</function>, <function>sd_journal_printv()</function>,
+ <function>sd_journal_send()</function>, <function>sd_journal_sendv()</function> and
+ <function>sd_journal_perror()</function> interfaces are available as a shared library, which can be compiled and
+ linked to with the <constant>libsystemd</constant> <citerefentry
+ project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> file.</para>
</refsect1>
<refsect1>
projects / thirdparty / systemd.git / blobdiff