The reason for the behavior you are observing is a race condition. The effects of close! on the pub aren't synchronous. Even though the channel is immediately closed before return, consumers need time to determine that it has been closed. At the point in time the pub determines that the source channel has been closed, it does indeed close all subscribed channels, as your last form demonstrates. However, in your second last form, all subscribed channels may have already been unsubscribed, due to unsub-all.
Thus, the solution is to not call unsubs-all if you want all subscribed channels to be closed as a consequence of closing the source channel. On Sunday, March 1, 2015 at 2:17:20 PM UTC+1, Jonas wrote: > > Hi all! > > I’m working with core.async pub/sub and ran into an issue which I don’t > quite understand. According to the clojure.core.async/sub docstring: > > > By default the channel will be closed when the source closes > > This is not the behaviour I’m seeing when I call > clojure.core.async/unsub-all immediately after I close the source channel. > > Example: > > (def source (async/chan)) > (def sub-chan (async/chan)) > (def pub (async/pub source (constantly "foo"))) > > ;; by default sub-chan should close when source closes > (async/sub pub "foo" sub-chan) > > ;; This will not close sub-chan > (async/thread > (async/close! source) > (async/unsub-all pub)) > > ;; This will close sub-chan > (async/thread > (async/close! source)) > > What is the reason for this behaviour? Is it unnecessary to call unsub-all > if I close the publications source channel? > > Thanks, > Jonas > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
