SD_JOURNAL_SEEK_HEAD(3)      sd_journal_seek_head      SD_JOURNAL_SEEK_HEAD(3)

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)

systemd 257.1                                          SD_JOURNAL_SEEK_HEAD(3)