Oops, I skipped the volatile keyword while reading the code snippet. Sorry :)
Luc P. > No, it means exactly the same thing as volatile in Java (and is implemented > in the Volatile Java class which holds a single volatile field). Basically > a "volatile box" since a field must exist inside a class. The semantics are > the same as Java - writes are guaranteed to be seen by subsequent reads on > any thread (that property is not guaranteed by a non-volatile field). > > vswap! on a volatile is syntactically similar to swap! on an atom but > without the atomicity guarantees. That is, vswap! consists of a read > followed by a write but this is non-transactional so another thread could > change the value in between. In other words: don't use this unless you can > enforce thread isolation or safety through other means. Thus, volatiles are > dangerous *by default*, unlike every other stateful thing in Clojure. > > Some stateful transducers use volatiles for performance and provide thread > isolation via how they are constructed and used. > > > > On Tuesday, September 9, 2014 12:06:36 PM UTC-5, Luc wrote: > > > > The keyword has different meaning > > depending on the language and > > context. > > > > Most of the time to prevent optimizations by the compiler to insure write > > ordering > > and some consistent view (Java use). > > > > Not here. It's meant to warn that > > nothing is guaranteed, no synchronization, no consistent view. > > > > It should be kept local (no leak > > outside of a narrow scope) and > > certainly not shared > > by multiple threads. > > > > Luc P. > > > > > > > Excuse my ignorance but does "volatile!" have anything to do with Java's > > > "volatile" keyword? Is there any relation at all? I'm not suggesting a > > name > > > change, but it can be confusing coming from that angle. Maybe a blurb in > > > the doc string? > > > > > > -- > > > You received this message because you are subscribed to the Google > > > Groups "Clojure" group. > > > To post to this group, send email to clo...@googlegroups.com > > <javascript:> > > > Note that posts from new members are moderated - please be patient with > > your first post. > > > To unsubscribe from this group, send email to > > > clojure+u...@googlegroups.com <javascript:> > > > 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+u...@googlegroups.com <javascript:>. > > > For more options, visit https://groups.google.com/d/optout. > > > > > -- > > Luc Prefontaine<lprefo...@softaddicts.ca <javascript:>> sent by ibisMail! > > > > -- > 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. > -- Softaddicts<lprefonta...@softaddicts.ca> sent by ibisMail from my ipad! -- 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.
