Hi Meikel, On 25 Jul 2011, at 22:46, Meikel Brandmeyer wrote:
> Am 25.07.2011 um 23:12 schrieb Sam Aaron: > > Since this is callback based, you can't return a value. Do you want more > something like a polling solution? Then you'll have to roll your own with an > atom and a clojure.lang.PersistentQueue. Sorry, I should have been more specific. The callback-based watchers are cool, but I don't believe they specifically address my problem (which I don't believe I sufficiently explained from the outset). Hopefully this is a more succinct and specific description. Is there a way to write the following in a thread safe manner without using a transaction: (def a (ref 1)) (defn update-and-check-whether-modified? [update-fn] (let [changed? (dosync (let [old-a @a new-a (alter a update-fn)] (not= old-a new-a)))] changed?)) Sam --- http://sam.aaron.name -- 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