NAME

       sd_journal_seek_head, sd_journal_seek_tail, sd_journal_seek_monotonic_usec,
       sd_journal_seek_realtime_usec, sd_journal_seek_cursor - Seek to a position in the journal

SYNOPSIS

       #include <systemd/sd-journal.h>

       int sd_journal_seek_head(sd_journal *j);

       int sd_journal_seek_tail(sd_journal *j);

       int sd_journal_seek_monotonic_usec(sd_journal *j, sd_id128_t boot_id, uint64_t usec);

       int sd_journal_seek_realtime_usec(sd_journal *j, uint64_t usec);

       int sd_journal_seek_cursor(sd_journal *j, const char *cursor);

DESCRIPTION

       sd_journal_seek_head() seeks to the beginning of the journal, i.e. to the position before
       the oldest available entry.

       Similarly, sd_journal_seek_tail() may be used to seek to the end of the journal, i.e. the
       position after the most recent available entry.

       sd_journal_seek_monotonic_usec() seeks to a position with the specified monotonic
       timestamp, i.e.  CLOCK_MONOTONIC. Since monotonic time restarts on every reboot a boot ID
       needs to be specified as well.

       sd_journal_seek_realtime_usec() seeks to a position with the specified realtime
       (wallclock) timestamp, i.e.  CLOCK_REALTIME. Note that the realtime clock is not
       necessarily monotonic. If a realtime timestamp is ambiguous, it is not defined which
       position is sought to.

       sd_journal_seek_cursor() seeks to the position at the specified cursor string. For details
       on cursors, see sd_journal_get_cursor(3). If no entry matching the specified cursor is
       found the call will seek to the next closest entry (in terms of time) instead.

       Note that these calls do not actually make any entry the new current entry, this needs to
       be done in a separate step with a subsequent sd_journal_next(3) invocation (or a similar
       call). Only then, entry data may be retrieved via sd_journal_get_data(3) or an entry
       cursor be retrieved via sd_journal_get_cursor(3). If no entry exists that matches exactly
       the specified seek address, the next closest is sought to. If sd_journal_next(3) is used,
       the closest following entry will be sought to, if sd_journal_previous(3) is used the
       closest preceding entry is sought to.

       After the seek is done, and sd_journal_next(3) or a similar call has been made,
       sd_journal_test_cursor(3) may be used to verify whether the newly selected entry actually
       matches the cursor.

RETURN VALUE

       The functions return 0 on success or a negative errno-style error code.

NOTES

       All functions listed here are thread-agnostic and only a single specific thread may
       operate on a given object during its entire lifetime. It's safe to allocate multiple
       independent objects and use each from a specific thread in parallel. However, it's not
       safe to allocate such an object in one thread, and operate or free it from any other, even
       if locking is used to ensure these threads don't operate on it at the very same time.

       Functions described here are available as a shared library, which can be compiled against
       and linked to with the libsystemd pkg-config(1) file.

HISTORY

       sd_journal_seek_head(), sd_journal_seek_tail(), sd_journal_seek_monotonic_usec(),
       sd_journal_seek_realtime_usec(), and sd_journal_seek_cursor() were added in version 187.

SEE ALSO

       systemd(1), sd-journal(3), sd_journal_open(3), sd_journal_next(3), sd_journal_get_data(3),
       sd_journal_get_cursor(3), sd_journal_get_realtime_usec(3)