sd_journal_seek_head
systemd
Developer
Lennart
Poettering
lennart@poettering.net
sd_journal_seek_head
3
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
#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. the oldest available entry.
Similarly, sd_journal_seek_tail() may
be used to seek to the end of the journal, i.e. the most recent
available entry.
sd_journal_seek_monotonic_usec() seeks
to the entry 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 the entry 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
entry located at the specified cursor string. For details on
cursors, see
sd_journal_get_cursor3.
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_cursor3.
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_next3
invocation (or a similar call). Only then, entry data may be
retrieved via
sd_journal_get_data3.
If no entry exists that matches exactly the specified seek
address, the next closest is sought to. If
sd_journal_next3
is used, the closest following entry will be sought to, if
sd_journal_previous3
is used the closest preceding entry is sought to.
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 thread may operate
on a given sd_journal object.
See Also
systemd1,
sd-journal3,
sd_journal_open3,
sd_journal_next3,
sd_journal_get_data3,
sd_journal_get_cursor3,
sd_journal_get_realtime_usec3