On 28/09/2009, Stephen Colebourne <scolebou...@btopenworld.com> wrote: > sebb wrote: > > > Where is that described? The first reference I found says that the > > local variable is a performance optimisation; it's the volatile > > keyword that makes it thread-safe: > > > > > http://technology.amis.nl/blog/4384/the-double-checked-locking-confusion > > also > > > http://jeremymanson.blogspot.com/2008/05/double-checked-locking.html > > > > But of course these could be wrong... > > > > http://java.sun.com/developer/technicalArticles/Interviews/bloch_effective_08_qa.html > > "The idiom is very fast but also complicated and delicate, so don't be > tempted to modify it in any way" >
That does not necessarily mean that the version without the temporary variable is wrong. As I see it, the fact that the variable is volatile is enough to ensure as-sequential operation, because the write of the volatile variable happens-before the read. > Stephen > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > For additional commands, e-mail: dev-h...@commons.apache.org > > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
