sd_journal_get_realtime_usec, sd_journal_get_monotonic_usec - Read timestamps from the current journal entry
#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);
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.
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().
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.
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)
This page is part of the systemd (systemd system and service manager) project. Information about the project can be found at ⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug report for this manual page, see ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This page was obtained from the project's upstream Git repository ⟨https://github.com/systemd/systemd.git⟩ on 2021-04-01. (At that time, the date of the most recent commit that was found in the repository was 2021-04-01.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to email@example.com systemd 248 SD_JOURNAL_GET_REALTIME_USEC(3)
Pages that refer to this page: sd-journal(3), sd_journal_get_cutoff_realtime_usec(3), sd_journal_get_data(3), sd_journal_next(3), sd_journal_seek_head(3), systemd.directives(7), systemd.index(7)