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Diffstat (limited to 'man/sd_journal_add_match.xml')
| -rw-r--r-- | man/sd_journal_add_match.xml | 366 |
1 files changed, 177 insertions, 189 deletions
diff --git a/man/sd_journal_add_match.xml b/man/sd_journal_add_match.xml index 21a5ab1342..420f56356a 100644 --- a/man/sd_journal_add_match.xml +++ b/man/sd_journal_add_match.xml @@ -1,6 +1,6 @@ <?xml version='1.0'?> <!--*-nxml-*--> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" - "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> <!-- This file is part of systemd. @@ -23,198 +23,186 @@ <refentry id="sd_journal_add_match"> - <refentryinfo> - <title>sd_journal_add_match</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_add_match</refentrytitle> - <manvolnum>3</manvolnum> - </refmeta> - - <refnamediv> - <refname>sd_journal_add_match</refname> - <refname>sd_journal_add_disjunction</refname> - <refname>sd_journal_add_conjunction</refname> - <refname>sd_journal_flush_matches</refname> - <refpurpose>Add or remove entry matches</refpurpose> - </refnamediv> - - <refsynopsisdiv> - <funcsynopsis> - <funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo> - - <funcprototype> - <funcdef>int <function>sd_journal_add_match</function></funcdef> - <paramdef>sd_journal *<parameter>j</parameter></paramdef> - <paramdef>const void *<parameter>data</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>int <function>sd_journal_add_disjunction</function></funcdef> - <paramdef>sd_journal *<parameter>j</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>int <function>sd_journal_add_conjunction</function></funcdef> - <paramdef>sd_journal *<parameter>j</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>void <function>sd_journal_flush_matches</function></funcdef> - <paramdef>sd_journal *<parameter>j</parameter></paramdef> - </funcprototype> - </funcsynopsis> - </refsynopsisdiv> - - <refsect1> - <title>Description</title> - - <para><function>sd_journal_add_match()</function> adds - a match by which to filter the entries of the journal - file. Matches applied with this call will filter what - can be iterated through and read from the journal file - via calls like - <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry> - and - <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Matches - are of the form <literal>FIELD=value</literal>, where - the field part is a short uppercase string consisting - only of 0-9, A-Z and the underscore. It may not begin - with two underscores or be the empty string. The value - part may be any value, including binary. If a match is - applied, only entries with this field set will be - iterated. Multiple matches may be active at the same - time: If they apply to different fields, only entries - with both fields set like this will be iterated. If - they apply to the same fields, only entries where the - field takes one of the specified values will be - iterated. Well known fields are documented in - <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>. Whenever - a new match is added the current entry position is - reset, and - <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry> (or a similar call) - needs to be called before entries can be read - again.</para> - - <para><function>sd_journal_add_disjunction()</function> - may be used to insert a disjunction (i.e. logical OR) - in the match list. If this call is invoked, all - previously added matches since the last invocation of - <function>sd_journal_add_disjunction()</function> or - <function>sd_journal_add_conjunction()</function> are - combined in an OR with all matches added afterwards, - until - <function>sd_journal_add_disjunction()</function> or - <function>sd_journal_add_conjunction()</function> is - invoked again to begin the next OR or AND - term. </para> - - <para><function>sd_journal_add_conjunction()</function> - may be used to insert a conjunction (i.e. logical AND) - in the match list. If this call is invoked, all - previously added matches since the last invocation of - <function>sd_journal_add_conjunction()</function> are - combined in an AND with all matches added afterwards, - until - <function>sd_journal_add_conjunction()</function> is - invoked again to begin the next AND term. The - combination of - <function>sd_journal_add_match()</function>, - <function>sd_journal_add_disjunction()</function> and - <function>sd_journal_add_conjunction()</function> may - be used to build complex search terms, even though - full logical expressions are not available. Note that - <function>sd_journal_add_conjunction()</function> - operates one level 'higher' than - <function>sd_journal_add_disjunction()</function>. It - is hence possible to build an expression of AND terms, - consisting of OR terms, consisting of AND terms, - consisting of OR terms of matches (the latter OR - expression is implicitly created for matches with the - same field name, see above).</para> - - <para><function>sd_journal_flush_matches()</function> - may be used to flush all matches, disjunction and - conjunction terms again. After this call all filtering - is removed and all entries in the journal will be - iterated again.</para> - - <para>Note that filtering via matches only applies to - the way the journal is read, it has no effect on storage - on disk.</para> - </refsect1> - - <refsect1> - <title>Return Value</title> - - <para><function>sd_journal_add_match()</function>, - <function>sd_journal_add_disjunction()</function> and - <function>sd_journal_add_conjunction()</function> - return 0 on success or a negative errno-style error - code. <function>sd_journal_flush_matches()</function> - returns nothing.</para> - </refsect1> - - <refsect1> - <title>Notes</title> - - <para>The <function>sd_journal_add_match()</function>, - <function>sd_journal_add_disjunction()</function>, - <function>sd_journal_add_conjunction()</function> and - <function>sd_journal_flush_matches()</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>Examples</title> - - <para>The following example adds matches to a journal - context object to iterate only through messages - generated by the Avahi service at the four error log - levels, plus all messages of the message ID - 03bb1dab98ab4ecfbf6fff2738bdd964 coming from any - service (this example lacks the necessary error - checking):</para> - - <programlisting>... + <refentryinfo> + <title>sd_journal_add_match</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_add_match</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_journal_add_match</refname> + <refname>sd_journal_add_disjunction</refname> + <refname>sd_journal_add_conjunction</refname> + <refname>sd_journal_flush_matches</refname> + <refpurpose>Add or remove entry matches</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_journal_add_match</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + <paramdef>const void *<parameter>data</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_add_disjunction</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_add_conjunction</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>void <function>sd_journal_flush_matches</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><function>sd_journal_add_match()</function> adds a match by + which to filter the entries of the journal file. Matches applied + with this call will filter what can be iterated through and read + from the journal file via calls like + <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry> + and + <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + Matches are of the form <literal>FIELD=value</literal>, where the + field part is a short uppercase string consisting only of 0-9, A-Z + and the underscore. It may not begin with two underscores or be + the empty string. The value part may be any value, including + binary. If a match is applied, only entries with this field set + will be iterated. Multiple matches may be active at the same time: + If they apply to different fields, only entries with both fields + set like this will be iterated. If they apply to the same fields, + only entries where the field takes one of the specified values + will be iterated. Well known fields are documented in + <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>. + Whenever a new match is added the current entry position is reset, + and + <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry> + (or a similar call) needs to be called before entries can be read + again.</para> + + <para><function>sd_journal_add_disjunction()</function> may be + used to insert a disjunction (i.e. logical OR) in the match list. + If this call is invoked, all previously added matches since the + last invocation of + <function>sd_journal_add_disjunction()</function> or + <function>sd_journal_add_conjunction()</function> are combined in + an OR with all matches added afterwards, until + <function>sd_journal_add_disjunction()</function> or + <function>sd_journal_add_conjunction()</function> is invoked again + to begin the next OR or AND term. </para> + + <para><function>sd_journal_add_conjunction()</function> may be + used to insert a conjunction (i.e. logical AND) in the match list. + If this call is invoked, all previously added matches since the + last invocation of + <function>sd_journal_add_conjunction()</function> are combined in + an AND with all matches added afterwards, until + <function>sd_journal_add_conjunction()</function> is invoked again + to begin the next AND term. The combination of + <function>sd_journal_add_match()</function>, + <function>sd_journal_add_disjunction()</function> and + <function>sd_journal_add_conjunction()</function> may be used to + build complex search terms, even though full logical expressions + are not available. Note that + <function>sd_journal_add_conjunction()</function> operates one + level 'higher' than + <function>sd_journal_add_disjunction()</function>. It is hence + possible to build an expression of AND terms, consisting of OR + terms, consisting of AND terms, consisting of OR terms of matches + (the latter OR expression is implicitly created for matches with + the same field name, see above).</para> + + <para><function>sd_journal_flush_matches()</function> may be used + to flush all matches, disjunction and conjunction terms again. + After this call all filtering is removed and all entries in the + journal will be iterated again.</para> + + <para>Note that filtering via matches only applies to the way the + journal is read, it has no effect on storage on disk.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para><function>sd_journal_add_match()</function>, + <function>sd_journal_add_disjunction()</function> and + <function>sd_journal_add_conjunction()</function> + return 0 on success or a negative errno-style error + code. <function>sd_journal_flush_matches()</function> + returns nothing.</para> + </refsect1> + + <refsect1> + <title>Notes</title> + + <para>The <function>sd_journal_add_match()</function>, + <function>sd_journal_add_disjunction()</function>, + <function>sd_journal_add_conjunction()</function> and + <function>sd_journal_flush_matches()</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>Examples</title> + + <para>The following example adds matches to a journal context + object to iterate only through messages generated by the Avahi + service at the four error log levels, plus all messages of the + message ID 03bb1dab98ab4ecfbf6fff2738bdd964 coming from any + service (this example lacks the necessary error checking):</para> + + <programlisting>... int add_matches(sd_journal *j) { - sd_journal_add_match(j, "_SYSTEMD_UNIT=avahi-daemon.service", 0); - sd_journal_add_match(j, "PRIORITY=0", 0); - sd_journal_add_match(j, "PRIORITY=1", 0); - sd_journal_add_match(j, "PRIORITY=2", 0); - sd_journal_add_match(j, "PRIORITY=3", 0); - sd_journal_add_disjunction(j); - sd_journal_add_match(j, "MESSAGE_ID=03bb1dab98ab4ecfbf6fff2738bdd964", 0); + sd_journal_add_match(j, "_SYSTEMD_UNIT=avahi-daemon.service", 0); + sd_journal_add_match(j, "PRIORITY=0", 0); + sd_journal_add_match(j, "PRIORITY=1", 0); + sd_journal_add_match(j, "PRIORITY=2", 0); + sd_journal_add_match(j, "PRIORITY=3", 0); + sd_journal_add_disjunction(j); + sd_journal_add_match(j, "MESSAGE_ID=03bb1dab98ab4ecfbf6fff2738bdd964", 0); }</programlisting> - </refsect1> + </refsect1> - <refsect1> - <title>See Also</title> + <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_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry> - </para> - </refsect1> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry> + </para> + </refsect1> </refentry> |