получить временную метку текущей итерации цикла событий (Retrieve current event loop iteration timestamp)
Имя (Name)
sd_event_now - Retrieve current event loop iteration timestamp
Синопсис (Synopsis)
#include <systemd/sd-event.h>
int sd_event_now(sd_event *event, clockid_t clock,
uint64_t *usec);
Описание (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 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.
Возвращаемое значение (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.
Примечание (Note)
These APIs are implemented as a shared library, which can be
compiled and linked to with the libsystemd pkg-config(1) file.
Смотри также (See also)
systemd(1), sd-event(3), sd_event_new(3), sd_event_add_time(3),
clock_gettime(2)
