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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | COLOPHON |
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SD_JOURN...IME_USEC(3) sd_journal_get_realtime_usecSD_JOURN...IME_USEC(3)
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 is safe to allocate multiple independent objects and
use each from a specific thread in parallel. However, it is 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
do not operate on it at the very same time.
Functions described here are available as a shared library, which
can be compiled against and linked to with the
libsystemd pkg-config(1) file.
sd_journal_get_realtime_usec() and sd_journal_get_monotonic_usec()
were added in version 187.
systemd(1), sd-journal(3), sd_journal_open(3), sd_journal_next(3),
sd_journal_get_data(3), sd_journal_get_seqnum(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 2025-02-02. (At that
time, the date of the most recent commit that was found in the
repository was 2025-02-02.) 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
man-pages@man7.org
systemd 258~devel SD_JOURN...IME_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_get_seqnum(3), sd_journal_next(3), sd_journal_seek_head(3), systemd.directives(7), systemd.index(7)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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