<funcprototype>
<funcdef>int <function>sd_journal_print</function></funcdef>
<paramdef>int <parameter>priority</parameter></paramdef>
- <paramdef>const char
* <parameter>format</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>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>const char
*<parameter>format</parameter></paramdef>
<paramdef>...</paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_journal_perror</function></funcdef>
- <paramdef>const char
* <parameter>message</parameter></paramdef>
+ <paramdef>const char
*<parameter>message</parameter></paramdef>
</funcprototype>
</funcsynopsis>
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>
+ <citerefentry project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>
or
- <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>. The
+ <citerefentry project='man-pages'><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
+ <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><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ <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
<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
+ 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>
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
+ 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
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
+ 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
<para><function>sd_journal_sendv()</function> is
similar to <function>sd_journal_send()</function> but
- takes an array of <literal>struct iovec</literal> (as
+ 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
+ structures in the array.
+ <function>sd_journal_sendv()</function> is
particularly useful to submit binary objects to the
journal where that is necessary.</para>
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
+ <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 <literal>LOG_ERR</literal> (3).</para>
+ priority used is <constant>LOG_ERR</constant> (3).</para>
<para>Note that <function>sd_journal_send()</function>
is a wrapper around
<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
+ 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>
+ <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
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
+ 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
<para>The four calls return 0 on success or a negative
errno-style error code. The
- <citerefentry><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ <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>
<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
+ are available as a shared library, which can be compiled
and linked to with the
- <literal>libsystemd-journal</literal>
- <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
</refsect1>
<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 project='man-pages'><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>
+ <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>
~ianmdlvl / elogind.git / blobdiff