sd_event_now(3) — Linux manual page


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
       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.

       Returned values may indicate the following problems:

           An invalid parameter was passed.

           Unsupported clock type.

           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),

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug
       report for this manual page, see
       ⟨⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨⟩ on 2020-08-13.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-08-11.)  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

systemd 246                                                  SD_EVENT_NOW(3)

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