systemd Developer Lennart Poettering lennart@poettering.net 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 sd_event_now() returns the timestamp the most recent event loop iteration began. This timestamp is taken right after returning from the event sleep, and before dispatching any event sources. The event parameter takes the even 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 its equivalent CLOCK_REALTIME_ALARM), CLOCK_MONOTONIC or CLOCK_BOOTTIME (or its equivalent CLOCK_BOOTTIME_ALARM), see clock_gettime2 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 non-zero in this case, while it is zero when the returned timestamp refers to the actual event loop iteration. If the first event loop iteration has not run yet sd_event_now() returns the requested timestamp in usec and returns a positive, non-zero return value. Otherwise, on success it will return the iteration's timestamp in usec and 0 as return value. On failure, the call returns a negative errno-style error code. Returned errors 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. systemd1, sd-event3, sd_event_new3, sd_event_add_time3, clock_gettime2