
Dear List, Is it possible to render things in the XServer with multiple threads? For example: dpy <- asks display myWin <- createSimpleWindow dpy (defaultRootWindow dpy) 0 0 10 10 black white _ <- forkOS $ do -- doStuff with myWin using dpy When I attempt doing things like that, I usually get a deadlock. Is there any way to do this (I know, X is old :( but no harm in asking). Thank you and best regards, Ernesto Rodriguez -- Ernesto Rodriguez Masters Student Computer Science Utrecht University www.netowork.me github.com/netogallo

On Sat, Nov 21, 2015 at 4:59 PM, Ernesto Rodriguez
When I attempt doing things like that, I usually get a deadlock. Is there any way to do this (I know, X is old :( but no harm in asking).
You can't, no, X11 is essentially incapable of it. (To the extent that gtk2/3 has hacks to forward stuff to the main thread.) Individual threads can open their own connections, a trick you'll see in various contribs, but you can't share stuff between them; the best you could do is send clientMessages from one thread to the other. (X11 has a call to "enable" multithreading. This wraps a Big Global Lock around all of X11. Even if you're using xcb, apparently, since if xcb could do it properly gtk wouldn't go to such lengths to avoid it.) -- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net

Oh well, thank you for the reply :) I am trying to do some networking stuff
in the X Monad. Do you think there is some workaround such that I do the
networking in an additional thread and then when it is done I fire some X11
event that XMonad can be programed to handle and then it can read the data
recovered from the network and display it?
Thanks
On Sat, Nov 21, 2015 at 10:07 PM, Brandon Allbery
On Sat, Nov 21, 2015 at 4:59 PM, Ernesto Rodriguez
wrote: When I attempt doing things like that, I usually get a deadlock. Is there any way to do this (I know, X is old :( but no harm in asking).
You can't, no, X11 is essentially incapable of it. (To the extent that gtk2/3 has hacks to forward stuff to the main thread.) Individual threads can open their own connections, a trick you'll see in various contribs, but you can't share stuff between them; the best you could do is send clientMessages from one thread to the other.
(X11 has a call to "enable" multithreading. This wraps a Big Global Lock around all of X11. Even if you're using xcb, apparently, since if xcb could do it properly gtk wouldn't go to such lengths to avoid it.)
-- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
-- Ernesto Rodriguez Masters Student Computer Science Utrecht University www.netowork.me github.com/netogallo

On Sat, Nov 21, 2015 at 5:29 PM, Ernesto Rodriguez
Oh well, thank you for the reply :) I am trying to do some networking stuff in the X Monad. Do you think there is some workaround such that I do the networking in an additional thread and then when it is done I fire some X11 event that XMonad can be programed to handle and then it can read the data recovered from the network and display it?
That would be the ClientMessage I mentioned. You would have your thread openDisplay for itself, do whatever, and then use sendMessage to send a ClientMessage event to the main thread; you then use handleEventHook to catch that event. -- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net

Sounds like an interesting Sunday project :) Thank you for the advice!
On Sat, Nov 21, 2015 at 10:31 PM, Brandon Allbery
On Sat, Nov 21, 2015 at 5:29 PM, Ernesto Rodriguez
wrote: Oh well, thank you for the reply :) I am trying to do some networking stuff in the X Monad. Do you think there is some workaround such that I do the networking in an additional thread and then when it is done I fire some X11 event that XMonad can be programed to handle and then it can read the data recovered from the network and display it?
That would be the ClientMessage I mentioned. You would have your thread openDisplay for itself, do whatever, and then use sendMessage to send a ClientMessage event to the main thread; you then use handleEventHook to catch that event.
-- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
-- Ernesto Rodriguez Masters Student Computer Science Utrecht University www.netowork.me github.com/netogallo
participants (2)
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Brandon Allbery
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Ernesto Rodriguez