AnyEvent::Impl::EventLib(3) User Contributed Perl Documentation AnyEvent::Impl::EventLib(3)

AnyEvent::Impl::EventLib - AnyEvent adaptor for Event::Lib

use AnyEvent;
use Event::Lib;

# this module gets loaded automatically as required

This module provides transparent support for AnyEvent. You don't have to do anything to make Event work with AnyEvent except by loading Event::Lib before creating the first AnyEvent watcher.

Note: the AnyEvent author has not found recent releases of Event::Lib to be even remotely working (not even the examples from the manpage or the testsuite work), so this event backend should be avoided (or somebody should step up and maintain it, hint, hint).

The Event::Lib module suffers from the same limitations and bugs as libevent, most notably it kills already-installed watchers on a file descriptor and it is unable to support fork. These are not fatal issues, and are worked-around by this module, but the Event::Lib perl module itself has many additional bugs such as taking references to file handles and callbacks instead of making a copy or freeing still-allocated scalars, causing memory corruption and random crashes. Only Tk rivals it in its brokenness.

This adaptor module employs the same workaround around the watcher problems as Tk and should therefore be avoided. (This was done for simplicity, one could in theory work around the problems with lower overhead by managing our own watchers).

Event::Lib also leaks file handles and memory and tends to just exit on problems.

It also doesn't work around the Windows bug of not signalling TCP connection failures.

It also doesn't work with many special devices on Linux (/dev/random works, /dev/urandom fails, /dev/tty works, /dev/null fails and so on).

Event::Lib does not support idle watchers. They could be emulated using low-priority timers but as the priority range (and availability) is not queryable nor guaranteed, and the default priority is likely the lowest one, this module cannot use them.

Avoid Event::Lib if you can.

AnyEvent, Event::Lib.

Marc Lehmann <>
2023-07-25 perl v5.38.0