Чтение отметок времени из текущей записи журнала (Read timestamps from the current journal entry)
Имя (Name)
sd_journal_get_realtime_usec, sd_journal_get_monotonic_usec -
Read timestamps from the current journal entry
Синопсис (Synopsis)
#include <systemd/sd-journal.h>
int sd_journal_get_realtime_usec(sd_journal *j, uint64_t *usec);
int sd_journal_get_monotonic_usec(sd_journal *j, uint64_t *usec,
sd_id128_t *boot_id);
Описание (Description)
sd_journal_get_realtime_usec() gets the realtime (wallclock)
timestamp of the current journal entry. It takes two arguments:
the journal context object and a pointer to a 64-bit unsigned
integer to store the timestamp in. The timestamp is in
microseconds since the epoch, i.e. CLOCK_REALTIME.
sd_journal_get_monotonic_usec() gets the monotonic timestamp of
the current journal entry. It takes three arguments: the journal
context object, a pointer to a 64-bit unsigned integer to store
the timestamp in, as well as a 128-bit ID buffer to store the
boot ID of the monotonic timestamp. The timestamp is in
microseconds since boot-up of the specific boot, i.e.
CLOCK_MONOTONIC. Since the monotonic clock begins new with every
reboot, it only defines a well-defined point in time when used
together with an identifier identifying the boot. See
sd_id128_get_boot(3) for more information. If the boot ID
parameter is passed NULL, the function will fail if the monotonic
timestamp of the current entry is not of the current system boot.
Note that these functions will not work before sd_journal_next(3)
(or related call) has been called at least once, in order to
position the read pointer at a valid entry.
Возвращаемое значение (Return value)
sd_journal_get_realtime_usec() and
sd_journal_get_monotonic_usec() returns 0 on success or a
negative errno-style error code. If the boot ID parameter was
passed NULL and the monotonic timestamp of the current journal
entry is not of the current system boot, -ESTALE is returned by
sd_journal_get_monotonic_usec().
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_id128_get_boot(3),
clock_gettime(2), sd_journal_get_cutoff_realtime_usec(3)
