Yeah, I didn't use evthread_use_pthreads. It works as expected now. Thanks :)
2011/5/2 Nick Mathewson <ni...@freehaven.net> > On Mon, May 2, 2011 at 7:18 PM, D.P. <piz...@gmail.com> wrote: > > Hi, I have a question regarding adding an event from a different thread > > (different from the one event_base_dispatch was called). > > Initially I create an event_base, add a listener socket to it, and do > > event_base_dispatch. When a listener socket gets an incoming connection, > it > > will add the new client socket (from inside the callback) to event_base. > > Everything works as expected up to this point (i.e. client socket > callback > > is invoked whenever there is data > > to read, and listener socket is invoked whenever there is another client > > trying to connect.) Now I add another socket using event_add, but from a > > different > > thread. Now let's say some data arrives at this socket that I have just > > added. It seems that a callback for this socket will only get invoked > > *after* there > > is some activity on the other two sockets (listener or client from > before). > > So if there is no activity at all on the two sockets that were added > before, > > the callback > > for this new socket will never get called. I tested the same code on OS X > > with kqueue and poll backends, and on Linux with epoll and poll. This > does > > not happen > > with epoll (the new socket callback will be fired even if there is no > > activity on the other two), but does happen with kqueue and poll. Is > there > > anything I can do > > to "force" an immediate refresh (while the event loop is running) of the > set > > of watched sockets for systems that use kqueue or poll? > > This sounds a lot like what would happen if you didn't enable > threading support. Check out the "Locks and Threading" part of > http://www.wangafu.net/~nickm/libevent-book/Ref1_libsetup.html . > > Basically, before you create any event_base that you're going to > access from more than one thread, you need to tell Libevent about your > threading library. On Windows, just call > int evthread_use_windows_threads(void); > On Linux or OS X or any place with pthreads, call > int evthread_use_pthreads(void); > If you're using some weird threading library, you'll need to teach > Libevent how to use it. > > Setting up threading performs two functions: it tells Libevent how to > do locking in order to protect data structures that are accessed from > multiple threads, and it also tells Libevent how to alert an > event_base whose dispatch function is running in one thread that it > needs to wake up and change the set of events that it's listening to. > > These functions are new in Libevent 2.0; in earlier versions there was > no realistic safe way to use an event_base from multiple threads > simultaneously. > > I'm starting to think that we need a FAQ. ;) > > -- > Nick > *********************************************************************** > To unsubscribe, send an e-mail to majord...@freehaven.net with > unsubscribe libevent-users in the body. >
