Greetings. I'm preparing a talk on event-driven programming in perl.
I'll talk about some of the guts of event-driven programming, since most
of my experiences were before any modules were available. But I've
learned just enough about the Event module to demonstrate its use as
well.
Is Event the best choice to recommend for event-driven programming? I
see that there's also the EventServer module - but given that it hasn't
changed in a few years, can we assume that it's obsolete? I also see
that POE looks like a viable choice. It seems to be more complex than
Event, but perhaps a more powerful option? POE's revision is less than
1, though, so is it still beta quality?
Also, I've tripped over some big signal concurrency issues looking at
writing an event loop using a blocking select call. I'm used to only
looking for signals, but adding IO and select makes it much more of a
mess. I looked at the Event source to see how it deals with it. It
appears that Event tries to be fail-safe by regularly polling the file
descriptors rather than pausing in the poll or select call waiting for
IO or a signal to happen. I can't tell how often it's called though
(seems to be happening in the null_loops_per_second function).
Can anyone confirm this analysis - does Event poll the file descriptors
that it's watching? How efficient is the implementation?
--
Danny Faught
Tejas Software Consulting
http://www.tejasconsulting.com
