x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
SD_EVENT_NOW(3) sd_event_now SD_EVENT_NOW(3)
NAME
sd_event_now - Retrieve current event loop iteration timestamp
SYNOPSIS
#include <systemd/sd-event.h>
int sd_event_now(sd_event *event, clockid_t clock, uint64_t *usec);
DESCRIPTION
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 <mu>s 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
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.
NOTES
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.
SEE ALSO
systemd(1), sd-event(3), sd_event_new(3), sd_event_add_time(3),
clock_gettime(2)
systemd 254 SD_EVENT_NOW(3)
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