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man: document that sd_journal_print() strips trailing whitespace
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Lennart Poettering
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@ -93,27 +93,20 @@
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<refsect1>
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<title>Description</title>
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<para><function>sd_journal_print()</function> may be used to
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submit simple, plain text log entries to the system journal. The
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first argument is a priority value. This is followed by a format
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string and its parameters, similar to
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<citerefentry project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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or
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<para><function>sd_journal_print()</function> may be used to submit simple, plain text log entries to the system
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journal. The first argument is a priority value. This is followed by a format string and its parameters, similar to
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<citerefentry project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry> or
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<citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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The priority value is one of
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<constant>LOG_EMERG</constant>,
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<constant>LOG_ALERT</constant>,
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<constant>LOG_CRIT</constant>,
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<constant>LOG_ERR</constant>,
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<constant>LOG_WARNING</constant>,
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<constant>LOG_NOTICE</constant>,
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<constant>LOG_INFO</constant>,
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<constant>LOG_DEBUG</constant>, as defined in
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<filename>syslog.h</filename>, see
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<citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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for details. It is recommended to use this call to submit log
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messages in the application locale or system locale and in UTF-8
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format, but no such restrictions are enforced.</para>
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The priority value is one of <constant>LOG_EMERG</constant>, <constant>LOG_ALERT</constant>,
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<constant>LOG_CRIT</constant>, <constant>LOG_ERR</constant>, <constant>LOG_WARNING</constant>,
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<constant>LOG_NOTICE</constant>, <constant>LOG_INFO</constant>, <constant>LOG_DEBUG</constant>, as defined in
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<filename>syslog.h</filename>, see <citerefentry
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project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> for details. It is
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recommended to use this call to submit log messages in the application locale or system locale and in UTF-8 format,
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but no such restrictions are enforced. Note that log messages written using this function are generally not
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expected to end in a new-line character. However, as all trailing whitespace (including spaces, new-lines,
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tabulators and carriage returns) are automatically stripped from the logged string, it is acceptable to specify one
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(or more). Leading whitespace (as well as inner whitespace) is left unmodified however.</para>
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<para><function>sd_journal_printv()</function> is similar to
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<function>sd_journal_print()</function> but takes a variable
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@ -123,35 +116,26 @@
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for more information) instead of the format string. It is
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otherwise equivalent in behavior.</para>
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<para><function>sd_journal_send()</function> may be used to submit
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structured log entries to the system journal. It takes a series of
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format strings, each immediately followed by their associated
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parameters, terminated by <constant>NULL</constant>. The strings
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passed should be of the format <literal>VARIABLE=value</literal>.
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The variable name must be in uppercase and consist only of
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characters, numbers and underscores, and may not begin with an
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underscore. (All assignments that do not follow this syntax will
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be ignored.) The value can be of any size and format. It is highly
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recommended to submit text strings formatted in the UTF-8
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character encoding only, and submit binary fields only when
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formatting in UTF-8 strings is not sensible. A number of
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well-known fields are defined, see
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<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
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for details, but additional application defined fields may be
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used. A variable may be assigned more than one value per
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entry.</para>
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<para><function>sd_journal_send()</function> may be used to submit structured log entries to the system journal. It
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takes a series of format strings, each immediately followed by their associated parameters, terminated by
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<constant>NULL</constant>. The strings passed should be of the format <literal>VARIABLE=value</literal>. The
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variable name must be in uppercase and consist only of characters, numbers and underscores, and may not begin with
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an underscore. (All assignments that do not follow this syntax will be ignored.) The value can be of any size and
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format. It is highly recommended to submit text strings formatted in the UTF-8 character encoding only, and submit
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binary fields only when formatting in UTF-8 strings is not sensible. A number of well-known fields are defined, see
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<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
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details, but additional application defined fields may be used. A variable may be assigned more than one value per
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entry. If this function is used, trailing whitespace is automatically removed from each formatted field.</para>
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<para><function>sd_journal_sendv()</function> is similar to
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<function>sd_journal_send()</function> but takes an array of
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<varname>struct iovec</varname> (as defined in
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<filename>uio.h</filename>, see
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<citerefentry project='man-pages'><refentrytitle>readv</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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for details) instead of the format string. Each structure should
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reference one field of the entry to submit. The second argument
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specifies the number of structures in the array.
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<function>sd_journal_sendv()</function> is particularly useful to
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submit binary objects to the journal where that is
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necessary.</para>
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<para><function>sd_journal_sendv()</function> is similar to <function>sd_journal_send()</function> but takes an
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array of <varname>struct iovec</varname> (as defined in <filename>uio.h</filename>, see <citerefentry
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project='man-pages'><refentrytitle>readv</refentrytitle><manvolnum>3</manvolnum></citerefentry> for details)
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instead of the format string. Each structure should reference one field of the entry to submit. The second argument
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specifies the number of structures in the array. <function>sd_journal_sendv()</function> is particularly useful to
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submit binary objects to the journal where that is necessary. Note that this function wil not strip trailing
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whitespace of the passed fields, but passes the specified data along unmodified. This is different from both
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<function>sd_journal_print()</function> and <function>sd_journal_send()</function> described above, which are based
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on format strings, and do strip trailing whitespace.</para>
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<para><function>sd_journal_perror()</function> is a similar to
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<citerefentry project='die-net'><refentrytitle>perror</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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@ -174,8 +158,8 @@
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<programlisting>sd_journal_print(LOG_INFO, "Hello World, this is PID %lu!", (unsigned long) getpid());
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sd_journal_send("MESSAGE=Hello World, this is PID %lu!", (unsigned long) getpid(),
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"PRIORITY=%i", LOG_INFO,
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NULL);</programlisting>
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"PRIORITY=%i", LOG_INFO,
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NULL);</programlisting>
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<para>Note that these calls implicitly add fields for the source
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file, function name and code line where invoked. This is
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