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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | COLOPHON |
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SD_EVENT_NOW(3) sd_event_now SD_EVENT_NOW(3)
sd_event_now - Retrieve current event loop iteration timestamp
#include <systemd/sd-event.h>
int sd_event_now(sd_event *event, clockid_t clock,
uint64_t *usec);
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.
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,
library or module instance.
Functions described here are available as a shared library, which
can be compiled against and linked to with the
libsystemd pkg-config(1) file.
The code described here uses getenv(3), which is declared to be
not multi-thread-safe. This means that the code calling the
functions described here must not call setenv(3) from a parallel
thread. It is recommended to only do calls to setenv() from an
early phase of the program when no other threads have been
started.
sd_event_now() was added in version 229.
systemd(1), sd-event(3), sd_event_new(3), sd_event_add_time(3),
clock_gettime(2)
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 2024-06-14. (At that
time, the date of the most recent commit that was found in the
repository was 2024-06-13.) 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 protected]
systemd 257~devel 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)
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HTML rendering created 2024-06-26 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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