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authorLennart Poettering <lennart@poettering.net>2016-07-01 17:10:26 -0700
committerLennart Poettering <lennart@poettering.net>2016-07-19 14:21:49 +0200
commit4c5db93f8a3fe5f332f07af0cf5d17260cb0e861 (patch)
tree8357ebaf454073cf16b0259dcdff4bc8c297688d /man/sd_journal_print.xml
parent8980058a3715f2dc96f38373b9550ef4e5b83662 (diff)
man: document that sd_journal_print() strips trailing whitespace
Diffstat (limited to 'man/sd_journal_print.xml')
-rw-r--r--man/sd_journal_print.xml86
1 files changed, 35 insertions, 51 deletions
diff --git a/man/sd_journal_print.xml b/man/sd_journal_print.xml
index 17fdc9c1f2..6fe078d88e 100644
--- a/man/sd_journal_print.xml
+++ b/man/sd_journal_print.xml
@@ -93,27 +93,20 @@
<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
+ <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>
+ 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. Note that log messages written using this function are generally not
+ expected to end in a new-line character. However, as all trailing whitespace (including spaces, new-lines,
+ tabulators and carriage returns) are automatically stripped from the logged string, it is acceptable to specify one
+ (or more). Leading whitespace (as well as inner whitespace) is left unmodified however.</para>
<para><function>sd_journal_printv()</function> is similar to
<function>sd_journal_print()</function> but takes a variable
@@ -123,35 +116,26 @@
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 project='man-pages'><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_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. If this function is used, trailing whitespace is automatically removed from each formatted field.</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
+ project='man-pages'><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. Note that this function wil not strip trailing
+ whitespace of the passed fields, but passes the specified data along unmodified. This is different from both
+ <function>sd_journal_print()</function> and <function>sd_journal_send()</function> described above, which are based
+ on format strings, and do strip trailing whitespace.</para>
<para><function>sd_journal_perror()</function> is a similar to
<citerefentry project='die-net'><refentrytitle>perror</refentrytitle><manvolnum>3</manvolnum></citerefentry>
@@ -174,8 +158,8 @@
<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>
+ "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