| SD_EVENT_NOW(3) | sd_event_now | SD_EVENT_NOW(3) |
.SH "NAME" sd_event_now - Retrieve current event loop iteration
timestamp
.SH "SYNOPSIS"
#include <systemd/sd-event.h>
.HP 408u int sd_event_now(sd_event *event,
clockid_t clock,
uint64_t *ret);
.SH "DESCRIPTION"
.PP 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 ret 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.
.SH "RETURN VALUE"
.PP If the first event loop iteration has not run yet sd_event_now()
writes current time to ret and returns a positive return value.
Otherwise, it will write the requested timestamp to ret and return 0.
On failure, the call returns a negative errno-style error code.
.SS "Errors"
.PP Returned values may indicate the following problems:
.PP -EINVAL
An invalid parameter was passed.
.RE
.PP -EOPNOTSUPP
Unsupported clock type.
.RE
.PP -ECHILD
The event loop object was created in a different process, library or module
instance.
.RE
.SH "NOTES"
.PP Functions described here are available as a shared library, which can be
compiled against and linked to with the
libsystemd pkg-config(1) file.
.PP All functions listed here are thread-agnostic and only a single thread
may operate on a given object at any given time. Different threads may
access the same object at different times. Multiple independent objects may
be used from different threads in parallel.
.PP 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.
.SH "HISTORY"
.PP sd_event_now() was added in version 229.
.SH "SEE ALSO"
.PP systemd(1), sd-event(3), sd_event_new(3),
sd_event_add_time(3), clock_gettime(2)
| systemd 262.2 |