sd_journal_seek_tail(3)

1SD_JOURNAL_SEEK_HEAD(3)      sd_journal_seek_head      SD_JOURNAL_SEEK_HEAD(3)
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3
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NAME

6       sd_journal_seek_head, sd_journal_seek_tail,
7       sd_journal_seek_monotonic_usec, sd_journal_seek_realtime_usec,
8       sd_journal_seek_cursor - Seek to a position in the journal
9

SYNOPSIS

11       #include <systemd/sd-journal.h>
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13       int sd_journal_seek_head(sd_journal *j);
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15       int sd_journal_seek_tail(sd_journal *j);
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17       int sd_journal_seek_monotonic_usec(sd_journal *j, sd_id128_t boot_id,
18                                          uint64_t usec);
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20       int sd_journal_seek_realtime_usec(sd_journal *j, uint64_t usec);
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22       int sd_journal_seek_cursor(sd_journal *j, const char *cursor);
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DESCRIPTION

25       sd_journal_seek_head() seeks to the beginning of the journal, i.e. to
26       the position before the oldest available entry.
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28       Similarly, sd_journal_seek_tail() may be used to seek to the end of the
29       journal, i.e. the position after the most recent available entry.
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31       sd_journal_seek_monotonic_usec() seeks to a position with the specified
32       monotonic timestamp, i.e.  CLOCK_MONOTONIC. Since monotonic time
33       restarts on every reboot a boot ID needs to be specified as well.
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35       sd_journal_seek_realtime_usec() seeks to a position with the specified
36       realtime (wallclock) timestamp, i.e.  CLOCK_REALTIME. Note that the
37       realtime clock is not necessarily monotonic. If a realtime timestamp is
38       ambiguous, it is not defined which position is sought to.
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40       sd_journal_seek_cursor() seeks to the position at the specified cursor
41       string. For details on cursors, see sd_journal_get_cursor(3). If no
42       entry matching the specified cursor is found the call will seek to the
43       next closest entry (in terms of time) instead. To verify whether the
44       newly selected entry actually matches the cursor, use
45       sd_journal_test_cursor(3).
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47       Note that these calls do not actually make any entry the new current
48       entry, this needs to be done in a separate step with a subsequent
49       sd_journal_next(3) invocation (or a similar call). Only then, entry
50       data may be retrieved via sd_journal_get_data(3) or an entry cursor be
51       retrieved via sd_journal_get_cursor(3). If no entry exists that matches
52       exactly the specified seek address, the next closest is sought to. If
53       sd_journal_next(3) is used, the closest following entry will be sought
54       to, if sd_journal_previous(3) is used the closest preceding entry is
55       sought to.
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RETURN VALUE

58       The functions return 0 on success or a negative errno-style error code.
59

NOTES

61       All functions listed here are thread-agnostic and only a single
62       specific thread may operate on a given object during its entire
63       lifetime. It's safe to allocate multiple independent objects and use
64       each from a specific thread in parallel. However, it's not safe to
65       allocate such an object in one thread, and operate or free it from any
66       other, even if locking is used to ensure these threads don't operate on
67       it at the very same time.
68
69       These APIs are implemented as a shared library, which can be compiled
70       and linked to with the libsystemd pkg-config(1) file.
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NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

NOTES

SEE ALSO