sd_event_now

systemd
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

## 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.

## 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.

## See Also

systemd 1, sd-event 3, sd_event_new 3, sd_event_add_time 3, clock_gettime 2