ищите позицию в журнале (seek to a position in the journal)
Имя (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
Синопсис (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);
Описание (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_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.
Возвращаемое значение (Return value)
The functions return 0 on success or a negative errno-style error
code.
Примечание (Note)
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.
Смотри также (See also)
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)
