sd_journal_seek_tail(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | COLOPHON

SD_JOURNAL_SEEK_HEAD(3)     sd_journal_seek_head     SD_JOURNAL_SEEK_HEAD(3)

NAME         top

       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         top

       #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         top

       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. To verify
       whether the newly selected entry actually matches the cursor, use
       sd_journal_test_cursor(3).

       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.

RETURN VALUE         top

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

NOTES         top

       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.

       These APIs are implemented as a shared library, which can be compiled
       and linked to with the libsystemd pkg-config(1) file.

SEE ALSO         top

       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)

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have a bug
       report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2020-08-13.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-08-11.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to man-pages@man7.org

systemd 246                                          SD_JOURNAL_SEEK_HEAD(3)

Pages that refer to this page: 30-systemd-environment-d-generator(7)systemd.index(7)