<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>
<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>
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
+ <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>
for details. It is recommended to use this call to
<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 behaviour.</para>
+ 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
+ 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. 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
+ 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.</para>
+ 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
+ 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>
+ <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 <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
<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>
- and and <function>sd_journal_print()</function> may
+ 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
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
<refsect1>
<title>Return Value</title>
- <para>The four calls return 0 on success or a
- negative errno-style error code.</para>
+ <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>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><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
</refsect1>
<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>systemd.journal-fields</refentrytitle><manvolnum>7</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><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff