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);
DESCRIPTIONsd_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_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). 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
The functions return 0 on success or a negative errno-style error code.
NOTES
The sd_journal_seek_head(), sd_journal_seek_tail(),
sd_journal_seek_monotonic_usec(), sd_journal_seek_realtime_usec(), and
sd_journal_seek_cursor() interfaces are available as a shared library,
which can be compiled and linked to with the libsystemd pkg-config(1)
file.
SEE ALSOsystemd(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 212SD_JOURNAL_SEEK_HEAD(3)
