From fe7222913a6e42b65bfd92bc38479714316cfaf3 Mon Sep 17 00:00:00 2001
From: root ev_prepare
/ev_check
watchers is
usually a better approach for this kind of thing.
Here are the gory details of what ev_loop
does:
* If there are no active watchers (reference count is zero), return. - - Queue prepare watchers and then call all outstanding watchers. +- Before the first iteration, call any pending watchers. + * If there are no active watchers (reference count is zero), return. + - Queue all prepare watchers and then call all outstanding watchers. - If we have been forked, recreate the kernel state. - Update the kernel state with all outstanding changes. - Update the "event loop time". @@ -1485,6 +1486,15 @@ with priority higher than or equal to the event loop and one coroutine of lower priority, but only once, using idle watchers to keep the event loop from blocking if lower-priority coroutines are active, thus mapping low-priority coroutines to idle/background tasks). +It is recommended to give
ev_check
watchers highest (EV_MAXPRI
) +priority, to ensure that they are being run before any other watchers +after the poll. Also,ev_check
watchers (andev_prepare
watchers, +too) should not activate ("feed") events into libev. While libev fully +supports this, they will be called before otherev_check
watchers did +their job. Asev_check
watchers are often used to embed other event +loops those other event loops might be in an unusable state until their +ev_check
watcher ran (always remind yourself to coexist peacefully with +others).