Phillip J. Eby wrote: > At 04:25 PM 2/15/2007 +1300, Greg Ewing wrote: >> Phillip J. Eby wrote: >>> peak.events, for example, lets you have multiple event loops running in >>> the same or different threads. >> Different threads is okay if you're willing to use threads, >> but you might not. The reason you're using an event loop >> may well be precisely so that you *don't* have to use >> threads. >> >> And... how do you run multiple event loops simultaneously >> in the *same* thread? > > When one is nested inside the other. This isn't a common need, but it's > occasionally useful if you need to switch back and forth between blocking > and non-blocking code. For example, suppose that you have some code that > wants to offer a synchronous interface to an asynchronous library... and > the synchronous code is being called from a FastCGI "accept" event > loop. The inner code can't use the outer event loop, because the outer > loop isn't going to proceed until the inner code is finished.
I actually have some code that works a little bit like this. I have a SelectLoop class that the application knows about and explicitly attaches transport objects to, and queues events on the loop. I have two ways to perform some actions in a "blocking" way. 1) I can create a new SelectLoop and move some transports temporarily from the main loop to the temporary loop to ignore all other events for a while. 2) I can re-enter the SelectLoop run() method and keep reacting to all events. Once the right event occurs - I exit from the nested run() and continue on. This does require a lot more mental effort though. Note that my code is nowhere near as ambitious as Twisted, but I watned to have the above flexibility. The code really only has to work on AIX and Linux, and in a limited way, Windows. - Dave _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
