On Thu, Mar 15, 2012 at 16:36, Bjorn <[email protected]> wrote: > Hi! > > First off, Node is great. I'm used to writing enterprise C++ servers using > the same evented paradigm - and Node is a really compelling and fun > alternative. However, the language barrier is a tough one. > I have a question, that while it's not directly Node related, it's been > brought up by my interest in Node, and I've searched *everywhere* for an > answer. Maybe you can help? > > Basically, the scenario I have that caused me to wonder was like this > (pseudocode) ; > > var outputBuffer = ""; > > SetInterval(function() { > outputBuffer += "asdf"; > }, 100); > > websocket.onMessage(function() { > // reply with outputbuffer > send(outputBuffer); // Race condition? > outputBuffer = ""; // What if SetInterval happened? > }); > > And the question is; what if SetInterval updates the outputBuffer between > the two red lines above? (which would cause me to loose one or more updates > since the variable is cleared after the send). In my C++ servers this is a > clear racecondition that needs to be protected by any number of means. > However, I suspect the Javascript event-model sucessfully prohibits the > racecondition (as I've seen lots and lots of javascript that potentially has > this issue). > > How can this code be safe and not have a race condition?
Because your JS code runs in a single thread. It's inconsequential when exactly the timer expires because its callback runs before or after the onMessage callback, never simultaneously. Callbacks don't interrupt one another either. -- Job Board: http://jobs.nodejs.org/ Posting guidelines: https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines You received this message because you are subscribed to the Google Groups "nodejs" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/nodejs?hl=en?hl=en
