Concurrency models (was: Timer)

Alex Martelli aleax at aleax.it
Tue Oct 28 15:44:39 CET 2003


Anthony Briggs wrote:
   ...
> I'll take your word for it. It sounds like a recipe for a lot of hair
> pulling to me. What happens if there's some part of your code that
> you don't want interrupted? eg. database commits, file access, any
> sort of time critical stuff, that sort of thing. Is there a way to
> switch it off?

Event-driven processing, AKA asynchronous processing, is not
pre-emptive: on the contrary, it relies on each event handler
(callback) terminating reasonably promptly and thus returning
to the main loop.  Hmmm -- ever programmed a GUI...?


>>I thought you were arguing AGAINST the 'after' functionality,
>>and therefore against event-driven programming...?!
> 
> Perhaps I was taking his words a little too literally. As far as I
> can tell with threads, etc, they're little better than voodoo. So the

Threads are best kept in their place by keeping them well separated
with Queue instances, although I wouldn't be surprised to hear that
the blood of a black roster strangled at midnight is also effective.

> after statement is at least as robust, even if it's a complete
> horror...

Nope -- the callback is done in the same thread that requested
it, so "thread separation" is not at issue.


Alex





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