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   sd_journal_get_realtime_usec    ( 3 )

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)