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+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<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 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>
-
- <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 <varname>va_list</varname> (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 <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><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 project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>. If
- the message string is passed as <constant>NULL</constant> 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 <constant>LOG_ERR</constant> (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());
+ <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 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>
+
+ <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
+ <varname>va_list</varname> (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 <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><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 project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+ If the message string is passed as <constant>NULL</constant> 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
+ <constant>LOG_ERR</constant> (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 project='man-pages'><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, filenames, and
- functions as metadata 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 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>
- is not running (the socket is not present), those
- functions do nothing, and also return 0.</para>
- </refsect1>
-
- <refsect1>
- <title>Async signal safety</title>
- <para><function>sd_journal_sendv()</function> is "async signal
- safe" in the meaning of <citerefentry><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
- </para>
-
- <para><function>sd_journal_print</function>,
- <function>sd_journal_printv</function>,
- <function>sd_journal_send</function>, and
- <function>sd_journal_perror</function> are
- not async signal safe.</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 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>
- <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 project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>perror</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- </para>
- </refsect1>
+ "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 project='man-pages'><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, filenames, and
+ functions as metadata 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 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>
+ is not running (the socket is not present), those functions do
+ nothing, and also return 0.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Async signal safety</title>
+ <para><function>sd_journal_sendv()</function> is "async signal
+ safe" in the meaning of
+ <citerefentry><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
+ </para>
+
+ <para><function>sd_journal_print</function>,
+ <function>sd_journal_printv</function>,
+ <function>sd_journal_send</function>, and
+ <function>sd_journal_perror</function> are
+ not async signal safe.</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 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>
+ <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 project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>perror</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ </para>
+ </refsect1>
</refentry>
projects / thirdparty / systemd.git / blobdiff