one_event

one_event($timeout): run one callback, waiting for an event if none is queued - at most $timeout seconds, 60 by default. Returns true if a callback ran. loop is built on it, but unlike loop it does not trap exceptions: a callback’s die propagates out of one_event.

One round: turn counted signals into events; if an event of priority better than 5 is queued, run it and return; otherwise wait for descriptors and timers (no longer than the next timer and $timeout), queue what happened, turn signals into events again, run the best queued event if there is one, and otherwise run an idle watcher.