[Questions]Events

Ned Konz ned at bike-nomad.com
Fri Jul 28 18:54:00 UTC 2000


Tim Rowledge wrote:

> IF (big if) one could rely on asynchronous event notification from the
> OS, maybe through threads, signals, service calls, traps, boojums or
> whatever they call'em, then we could sensibly do interrupt driven events
> to the image. I just realised that a possible reason the interrupt-key
> problem exists in Squeak and didn't ever seem to in ST-80 is that ST-80
> handled the interrupt-key in the event loop, not with a special separate
> Process/VM handler. Maybe changing that would help? Don't forget that
> not all OSs provide threads - certainly a lot of interesting ones for
> small and embedded systems don't (my main interests).

Does anyone know whether it's possible to signal an external
Semaphore asynchronously? I looked at doing just this (including using SIGIO)
for the Serial stuff, but didn't know how it would work.

Otherwise, you'd have to set a flag and then signal the Semaphore from
the regular poll loop. Not a big gain for Serial and Socket communications
under Unix, as you can already use select() to check readiness.

I was also going to generalize the polling (at least under Unix) to make it
possible for any module that needs to be called for polling and/or needs
to have file handles checked to do so.

Is this work still useful?

-- 
Ned Konz
currently: Stanwood, WA
email:     ned at bike-nomad.com
homepage:  http://bike-nomad.com





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