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diff --git a/man/sd_journal_print.xml b/man/sd_journal_print.xml new file mode 100644 index 0000000000..7742268f5d --- /dev/null +++ b/man/sd_journal_print.xml @@ -0,0 +1,251 @@ +<?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"> + +<!-- + This file is part of systemd. + + Copyright 2012 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +--> + +<refentry id="sd_journal_print"> + + <refentryinfo> + <title>sd_journal_print</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_journal_print</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_journal_print</refname> + <refname>sd_journal_printv</refname> + <refname>sd_journal_send</refname> + <refname>sd_journal_sendv</refname> + <refname>sd_journal_perror</refname> + <refname>SD_JOURNAL_SUPPRESS_LOCATION</refname> + <refpurpose>Submit log entries to the journal</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_journal_print</function></funcdef> + <paramdef>int <parameter>priority</parameter></paramdef> + <paramdef>const char* <parameter>format</parameter></paramdef> + <paramdef>...</paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_printv</function></funcdef> + <paramdef>int <parameter>priority</parameter></paramdef> + <paramdef>const char* <parameter>format</parameter></paramdef> + <paramdef>va_list <parameter>ap</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_send</function></funcdef> + <paramdef>const char* <parameter>format</parameter></paramdef> + <paramdef>...</paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_sendv</function></funcdef> + <paramdef>const struct iovec *<parameter>iov</parameter></paramdef> + <paramdef>int <parameter>n</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_perror</function></funcdef> + <paramdef>const char* <parameter>message</parameter></paramdef> + </funcprototype> + + </funcsynopsis> + </refsynopsisdiv> + + <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><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry> + or + <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>. The + priority value is one of + <literal>LOG_EMERG</literal>, + <literal>LOG_ALERT</literal>, + <literal>LOG_CRIT</literal>, + <literal>LOG_ERR</literal>, + <literal>LOG_WARNING</literal>, + <literal>LOG_NOTICE</literal>, + <literal>LOG_INFO</literal>, + <literal>LOG_DEBUG</literal>, as defined in + <filename>syslog.h</filename>, see + <citerefentry><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> + + <para><function>sd_journal_printv()</function> is + similar to <function>sd_journal_print()</function> but + takes a variable argument list encapsulated in an + object of type <literal>va_list</literal> (see + <citerefentry><refentrytitle>stdarg</refentrytitle><manvolnum>3</manvolnum></citerefentry> + 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 NULL. 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 <literal>struct iovec</literal> (as + defined in <filename>uio.h</filename>, see + <citerefentry><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_perror()</function> is a + similar to + <citerefentry><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 the current error code + stored in + <citerefentry><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>. If + the message string is passed as NULL or empty string + only the error string representation will be written, + prefixed with nothing. An additional journal field + ERRNO= is included in the entry containing the numeric + error code formatted as decimal string. The log + priority used is <literal>LOG_ERR</literal> (3).</para> + + <para>Note that <function>sd_journal_send()</function> + is a wrapper around + <function>sd_journal_sendv()</function> to make it + easier to use when only text strings shall be + submitted. Also, the following two calls are + mostly equivalent:</para> + + <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> + + <para>Note that these calls implicitly add fields for + the source file, function name and code line where + invoked. This is implemented with macros. If this is + not desired it can be turned off by defining + SD_JOURNAL_SUPPRESS_LOCATION before including + <filename>sd-journal.h</filename>.</para> + + <para><citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> + and <function>sd_journal_print()</function> may + largely be used interchangeably + functionality-wise. However, note that log messages + logged via the former take a different path to the + journal server than the later, and hence global + chronological ordering between the two streams cannot + be guaranteed. Using + <function>sd_journal_print()</function> has the + benefit of logging source code line, file names, and + functions as meta data along all entries, and + guaranteeing chronological ordering with structured + log entries that are generated via + <function>sd_journal_send()</function>. Using + <function>syslog()</function> has the benefit of being + more portable.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>The four calls return 0 on success or a negative + errno-style error code. The + <citerefentry><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry> + variable itself is not altered.</para> + </refsect1> + + <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 shared library, which can be compiled + and linked to with the + <literal>libsystemd-journal</literal> + <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> + file.</para> + </refsect1> + + <refsect1> + <title>See Also</title> + + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_stream_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>perror</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |