You do not have to. Everything inside your dosync-block will happen atomically, meaning print-info will either see the values of source-account and dest-account before your transaction happened or after it's done his work.
-- Ph. Siegmantel 2010/2/20 Jack Fang <jack.fang1...@gmail.com> > Hi,all > > I am new to clojure. Now I hava a problem about read > transcation. > Suppose now I write some code about bank transfer. So this is > the source-account and destination-account > > //The code > (def source-account (ref 1000)) > (def dest-account (ref 0)) > > And I have a function to do the account transfer. > //The code > (defn take-money [account num] > (- account num)) > > (defn despoite [account num] > (+ account num)) > > (defn transfer-money [num] > (dosync (alter source-account take-money num) > (alter dest-account despoite num))) > > And I have a another function to print the source account and dest > acoount information. > //The code > (defn print-info [] > (do > (println @source-account) > (println @dest-account))) > > Suppose the transfer-money and print-info are run in different > thread. With the current Clojure STM, is it possible that print-info > prints the old source-account information and modified dest-account > information? Do I need to add a dosync to the print-info function? I > read the Programming Clojure. It says do not have side-effect on a > transaction. If I add dosync to the print-info, do I need to use agent > to print the info? Hope somebody can help me. > > Thank. > Jack > > > -- > 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<clojure%2bunsubscr...@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 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
