sd_journal_add_conjunction man page on OpenMandriva

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SD_JOURNAL_ADD_MATCH(3)	     sd_journal_add_match      SD_JOURNAL_ADD_MATCH(3)

NAME
       sd_journal_add_match, sd_journal_add_disjunction,
       sd_journal_add_conjunction, sd_journal_flush_matches - Add or remove
       entry matches

SYNOPSIS
       #include <systemd/sd-journal.h>

       int sd_journal_add_match(sd_journal* j, const void* data, size_t size);

       int sd_journal_add_disjunction(sd_journal* j);

       int sd_journal_add_conjunction(sd_journal* j);

       void sd_journal_flush_matches(sd_journal* j);

DESCRIPTION
       sd_journal_add_match() 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
       sd_journal_next(3) and sd_journal_get_data(3). Matches are of the form
       "FIELD=value", 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 systemd.journal-
       fields(7). Whenever a new match is added the current entry position is
       reset, and sd_journal_next(3) (or a similar call) needs to be called
       before entries can be read again.

       sd_journal_add_disjunction() 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 sd_journal_add_disjunction()
       or sd_journal_add_conjunction() are combined in an OR with all matches
       added afterwards, until sd_journal_add_disjunction() or
       sd_journal_add_conjunction() is invoked again to begin the next OR or
       AND term.

       sd_journal_add_conjunction() 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 sd_journal_add_conjunction()
       are combined in an AND with all matches added afterwards, until
       sd_journal_add_conjunction() is invoked again to begin the next AND
       term. The combination of sd_journal_add_match(),
       sd_journal_add_disjunction() and sd_journal_add_conjunction() may be
       used to build complex search terms, even though full logical
       expressions are not available. Note that sd_journal_add_conjunction()
       operates one level 'higher' than sd_journal_add_disjunction(). 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).

       sd_journal_flush_matches() 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.

       Note that filtering via matches only applies to the way the journal is
       read, it has no effect on storage on disk.

RETURN VALUE
       sd_journal_add_match(), sd_journal_add_disjunction() and
       sd_journal_add_conjunction() return 0 on success or a negative
       errno-style error code.	sd_journal_flush_matches() returns nothing.

NOTES
       The sd_journal_add_match(), sd_journal_add_disjunction(),
       sd_journal_add_conjunction() and sd_journal_flush_matches() interfaces
       are available as a shared library, which can be compiled and linked to
       with the libsystemd-journal pkg-config(1) file.

EXAMPLES
       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):

	   ...
	   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);
	   }

SEE ALSO
       systemd(1), sd-journal(3), sd_journal_open(3), sd_journal_next(3),
       sd_journal_get_data(3), systemd.journal-fields(7)

systemd 208					       SD_JOURNAL_ADD_MATCH(3)
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