var loop = true,
block = setTimeout(function(){loop = false}, 1);
while(loop);
It's a deadlock, because while loop is waiting that condition is setted to false while timeout, the one who'll set that condition to false, is waiting while loop end to be executed.
THe same behaviour is expected with Ajax or every other async interaction.
This is JavaScript, have fun :-)
Huh so don't use this?
ReplyDeleteso don't believe who say JavaScript is multi threading ;)
ReplyDelete"Huh so don't use this? "
ReplyDeleteThis is an example of a typical method to itterate through a trees of data - people do it all the time.
The example is just showing how things can go wrong - but in it's simplistic display it makes it quite apparent that there is an issue. A better real-life example might make things more relevent.
Bill
I beg to differ, looks like a simple infinite loop. The while loop never looses control. What this does prove however, is that javascript is not multi-threaded since the timeout script will never get a chance to run.
ReplyDeleteWhat this does prove however, is that javascript is not multi-threaded since the timeout script will never get a chance to run.
ReplyDeleteOk Juanito, this was this post goal :-)
However, usually a deadlock is created when one operation wait another one to be executed and vice-versa.
Since JavaScript is single threading, it's really simple to create a "sort" of deadlock but your probably right, this deadlock example is not so clear (but with a single threading enviroment it's quite difficult to create a real deadlock example, isn't it?)
Yeah....thats true..but..only firefox cannot detect it and hangs...else...all browser can detect them and prompts warning...
ReplyDeletei like your style of explaining. thank you very much and keep going on such interesting topics.
ReplyDelete