NAME

       sd_journal_get_realtime_usec, sd_journal_get_monotonic_usec - Read timestamps from the
       current journal entry

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);

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.

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().

NOTES

       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.

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)