Re: [Pysdl-devel] Threads and events

[Jan E. <ch...@in...>]

On Fri, 6 Oct 2000, Pete Shinners wrote:

>hi jan. most of the things you're asking about largely depend
>on how the SDL library handles things. on many platforms (perhaps
>all) the event handling is thread safe. in fact on some (like X11)
>the event handling is already handled in a separate thread.

Ok, sounds fine.

>as far as handling threads, you'll find pysdl does not support
>the SDL threading routines. this is because python already 
>comes with great crossplatform threading. (also with it's own
>semaphores/mutexes/locks). your best bet is to peek at the
>'Threading' module

...which was exactly the page I had in front of me. I have no problems
using threads, just the general thread-safeness of the system is
interesting. And problems with that tend to be hard to spot, very hard to
debug and otherwise just a PITA.

>because the event objects are written as C extensions, it is
>not easy to modify them much from the python side. your idea
>for a global user-data queue sounds like the best idea for now.

Yep, it should also be quite simple, as there are ready synchronized
queues etc.

>just a note here, you might have good results with the 'select'
>module. this works on windows and unix. it allows you to do
>asynchronous networking on a single thread. it even works well
>with multiple sockets. i've never looked into it too far, but
>i've heard good things about it. anyways if the threading gets
>too tricky, it might be a good alternative.

I don't want to use that one. I'm more confident with splitting up my game
in as many logical modules as possible, and threads are a good idea of a
logical module in my world. Sure, they add complexity and reduce speed
(maybe), but will end up making my main event loop simpler. I can then
just sit an wait for some event to occur (user does something, packet
arrives etc).

>good luck with everything

It will be needed. I'll return and cry when all fails... :-) Btw, anyone
here interested in strategic games with too much time on their hands and
an urge to help with some design issues (or coding too, of course)?

--------------------+--------------------------------------------------------
Jan 'Chakie' Ekholm |     Balrog New Media    http://www.balrog.fi/
   Linux Inside     | I'm the blue screen of death, nobody hears your screams