sd_event_now — Retrieve current event loop iteration timestamp
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
parameter specifies the event loop object to retrieve the timestamp
clock parameter specifies the clock to
retrieve the timestamp for, and is one of
CLOCK_REALTIME (or equivalently
CLOCK_BOOTTIME (or equivalently
for more information on the various clocks. The retrieved
timestamp is stored in the
in μs since the clock's epoch. If this function is invoked before
the first event loop iteration, the current time is returned, as
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
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.
Functions described here are available as a shared
library, which can be compiled against and linked to with the
The code described here uses
which is declared to be not multi-thread-safe. This means that the code calling the functions described
here must not call
from a parallel thread. It is recommended to only do calls to
from an early phase of the program when no other threads have been started.
sd_event_now() was added in version 229.