sd_journal_seek_head
systemd
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. 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_cursor3.
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_next3
invocation (or a similar call). Only then, entry data may be retrieved via
sd_journal_get_data3
or an entry cursor be retrieved via
sd_journal_get_cursor3.
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.
After the seek is done, and
sd_journal_next3
or a similar call has been made,
sd_journal_test_cursor3
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
See Also
systemd1,
sd-journal3,
sd_journal_open3,
sd_journal_next3,
sd_journal_get_data3,
sd_journal_get_cursor3,
sd_journal_get_realtime_usec3