sd_event_now(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | COLOPHON

SD_EVENT_NOW(3)               sd_event_now               SD_EVENT_NOW(3)

NAME         top

       sd_event_now - Retrieve current event loop iteration timestamp

SYNOPSIS         top

       #include <systemd/sd-event.h>

       int sd_event_now(sd_event *event, clockid_t clock,
                        uint64_t *usec);

DESCRIPTION         top

       sd_event_now() returns the time when the most recent event loop
       iteration began. A timestamp is taken right after returning from
       the event sleep, and before dispatching any event sources. The
       event parameter specifies the event loop object to retrieve the
       timestamp from. The clock parameter specifies the clock to
       retrieve the timestamp for, and is one of CLOCK_REALTIME (or
       equivalently CLOCK_REALTIME_ALARM), CLOCK_MONOTONIC, or
       CLOCK_BOOTTIME (or equivalently CLOCK_BOOTTIME_ALARM), see
       clock_gettime(2) for more information on the various clocks. The
       retrieved timestamp is stored in the usec parameter, in µs since
       the clock's epoch. If this function is invoked before the first
       event loop iteration, the current time is returned, as reported
       by clock_gettime(). To distinguish this case from a regular
       invocation the return value will be positive, and zero when the
       returned timestamp refers to an actual event loop iteration.

RETURN VALUE         top

       If the first event loop iteration has not run yet sd_event_now()
       writes current time to usec and returns a positive return value.
       Otherwise, it will write the requested timestamp to usec and
       return 0. On failure, the call returns a negative errno-style
       error code.

   Errors
       Returned values may indicate the following problems:

       -EINVAL
           An invalid parameter was passed.

       -EOPNOTSUPP
           Unsupported clock type.

       -ECHILD
           The event loop object was created in a different process.

NOTES         top

       These APIs are implemented as a shared library, which can be
       compiled and linked to with the libsystemd pkg-config(1) file.

SEE ALSO         top

       systemd(1), sd-event(3), sd_event_new(3), sd_event_add_time(3),
       clock_gettime(2)

COLOPHON         top

       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
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       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 248                                              SD_EVENT_NOW(3)

Pages that refer to this page: sd-event(3)sd_event_add_child(3)sd_event_add_defer(3)sd_event_add_inotify(3)sd_event_add_io(3)sd_event_add_signal(3)sd_event_add_time(3)systemd.directives(7)systemd.index(7)